WorldWideScience

Sample records for abiotic stress tolerance

  1. Improving abiotic stress tolerance of quinoa

    DEFF Research Database (Denmark)

    Yang, Aizheng

    that quinoa has the potential to grow under a range of abiotic stresses, tolerating levels regarded as stresses in other crop species. Therefore cultivation of quinoa (Chenopodium quinoa Willd.) could be an alternative option in such regions. Even though quinoa is more tolerant to abiotic stress than most...... growth promoting bacteria (PGPB) and priming seed (such as with saponin) were involved to improve drought and salinity stress and climate adaptability in quinoa. During PhD research, the effect of theses strategies on physiological and agronomic characteristics of quinoa were studied in detail....

  2. Safety aspects of genetically modified crops with abiotic stress tolerance

    NARCIS (Netherlands)

    Liang, C.; Prins, T.W.; Wiel, van de C.C.M.; Kok, E.J.

    2014-01-01

    Abiotic stress, such as drought, salinity, and temperature extremes, significantly reduce crop yields. Hence, development of abiotic stress-tolerant crops by modern biotechnology may contribute to global food security. Prior to introducing genetically modified crops with abiotic stress tolerance to

  3. Phenotyping for Abiotic Stress Tolerance in Maize

    Institute of Scientific and Technical Information of China (English)

    Benhilda Masuka; Jose Luis Araus; Biswanath Das; Kai Sonder; Jill E. Cairns

    2012-01-01

    The ability to quickly develop germplasm having tolerance to several complex polygenic inherited abiotic and biotic stresses combined is critical to the resilience of cropping systems in the face of climate change.Molecular breeding offers the tools to accelerate cereal breeding; however,suitable phenotyping protocols are essential to ensure that the much-anticipated benefits of molecular breeding can be realized.To facilitate the full potential of molecular tools,greater emphasis needs to be given to reducing the within-experimental site variability,application of stress and characterization of the environment and appropriate phenotyping tools.Yield is a function of many processes throughout the plant cycle,and thus integrative traits that encompass crop performance over time or organization level (i.e.canopy level) will provide a better alternative to instantaneous measurements which provide only a snapshot of a given plant process.Many new phenotyping tools based on remote sensing are now available including non-destructive measurements of growth-related parameters based on spectral reflectance and infrared thermometry to estimate plant water status.Here we describe key field phenotyping protocols for maize with emphasis on tolerance to drought and low nitrogen.

  4. Molecular approaches to improve rice abiotic stress tolerance.

    Science.gov (United States)

    Mizoi, Junya; Yamaguchi-Shinozaki, Kazuko

    2013-01-01

    Abiotic stress is a major factor limiting productivity of rice crops in large areas of the world. Because plants cannot avoid abiotic stress by moving, they have acquired various mechanisms for stress tolerance in the course of their evolution. Enhancing or introducing such mechanisms in rice is one effective way to develop stress-tolerant cultivars. Based on physiological studies on stress responses, recent progress in plant molecular biology has enabled discovery of many genes involved in stress tolerance. These genes include regulatory genes, which regulate stress response (e.g., transcription factors and protein kinases), and functional genes, which protect the cell (e.g., enzymes for generating protective metabolites and proteins). Both kinds of genes are used to increase stress tolerance in rice. In addition, several quantitative trait loci (QTLs) associated with higher stress tolerance have been cloned, contributing to the discovery of significantly important genes for stress tolerance.

  5. Circadian regulation of abiotic stress tolerance in plants.

    Science.gov (United States)

    Grundy, Jack; Stoker, Claire; Carré, Isabelle A

    2015-01-01

    Extremes of temperatures, drought and salinity cause widespread crop losses throughout the world and impose severe limitations on the amount of land that can be used for agricultural purposes. Hence, there is an urgent need to develop crops that perform better under such abiotic stress conditions. Here, we discuss intriguing, recent evidence that circadian clock contributes to plants' ability to tolerate different types of environmental stress, and to acclimate to them. The clock controls expression of a large fraction of abiotic stress-responsive genes, as well as biosynthesis and signaling downstream of stress response hormones. Conversely, abiotic stress results in altered expression and differential splicing of the clock genes, leading to altered oscillations of downstream stress-response pathways. We propose a range of mechanisms by which this intimate coupling between the circadian clock and environmental stress-response pathways may contribute to plant growth and survival under abiotic stress.

  6. Recent Advances in Polyamine Metabolism and Abiotic Stress Tolerance

    Directory of Open Access Journals (Sweden)

    Parimalan Rangan

    2014-01-01

    Full Text Available Global warming is an alarming problem in agriculture and its effect on yield loss has been estimated to be five per cent for every degree centigrade rise in temperature. Plants exhibit multiple mechanisms like optimizing signaling pathway, involvement of secondary messengers, production of biomolecules specifically in response to stress, modulation of various metabolic networks in accordance with stress, and so forth, in order to overcome abiotic stress factors. Many structural genes and networks of pathway were identified and reported in plant systems for abiotic stress tolerance. One such crucial metabolic pathway that is involved in normal physiological function and also gets modulated during stress to impart tolerance is polyamine metabolic pathway. Besides the role of structural genes, it is also important to know the mechanism by which these structural genes are regulated during stress. Present review highlights polyamine biosynthesis, catabolism, and its role in abiotic stress tolerance with special reference to plant systems. Additionally, a system based approach is discussed as a potential strategy to dissect the existing variation in crop species in unraveling the interacting regulatory components/genetic determinants related to PAs mediated abiotic stress tolerance.

  7. Transcriptome Analysis of Sunflower Genotypes with Contrasting Oxidative Stress Tolerance Reveals Individual- and Combined- Biotic and Abiotic Stress Tolerance Mechanisms.

    Science.gov (United States)

    Ramu, Vemanna S; Paramanantham, Anjugam; Ramegowda, Venkategowda; Mohan-Raju, Basavaiah; Udayakumar, Makarla; Senthil-Kumar, Muthappa

    2016-01-01

    In nature plants are often simultaneously challenged by different biotic and abiotic stresses. Although the mechanisms underlying plant responses against single stress have been studied considerably, plant tolerance mechanisms under combined stress is not understood. Also, the mechanism used to combat independently and sequentially occurring many number of biotic and abiotic stresses has also not systematically studied. From this context, in this study, we attempted to explore the shared response of sunflower plants to many independent stresses by using meta-analysis of publically available transcriptome data and transcript profiling by quantitative PCR. Further, we have also analyzed the possible role of the genes so identified in contributing to combined stress tolerance. Meta-analysis of transcriptomic data from many abiotic and biotic stresses indicated the common representation of oxidative stress responsive genes. Further, menadione-mediated oxidative stress in sunflower seedlings showed similar pattern of changes in the oxidative stress related genes. Based on this a large scale screening of 55 sunflower genotypes was performed under menadione stress and those contrasting in oxidative stress tolerance were identified. Further to confirm the role of genes identified in individual and combined stress tolerance the contrasting genotypes were individually and simultaneously challenged with few abiotic and biotic stresses. The tolerant hybrid showed reduced levels of stress damage both under combined stress and few independent stresses. Transcript profiling of the genes identified from meta-analysis in the tolerant hybrid also indicated that the selected genes were up-regulated under individual and combined stresses. Our results indicate that menadione-based screening can identify genotypes not only tolerant to multiple number of individual biotic and abiotic stresses, but also the combined stresses.

  8. Understanding Abiotic Stress Tolerance Mechanisms: Recent Studies on Stress Response in Rice

    Institute of Scientific and Technical Information of China (English)

    Ji-Ping Gao; Dai-Yin Chao; Hong-Xuan Lin

    2007-01-01

    Abiotic stress is the main factor negatively affecting crop growth and productivity worldwide. The advances in physiology, genetics, and molecular biology have greatly improved our understanding of plant responses to stresses. Rice plants are sensitive to various abiotic stresses. In this short review, we present recent progresses in adaptation of rice to salinity, water deficit and submergence. Many studies show that salt tolerance is tightly associated with the ability to maintain ion homeostasis under salinity. Na+ transporter SKC1 unloads NaMrom xylem, plasma membrane NaVHTantiporter SOS1 excludes sodium out of cytosol and tonoplast Na+/H+antiporter NHX1 sequesters Na+ into the vacuole. Silicon deposition in exodermis and endodermis of rice root reduces sodium transport through the apoplastic pathway. A number of transcription factors regulate stress-inducible gene expression that leads to initiating stress responses and establishing plant stress tolerance. Overexpression of some transcription factors, including DREB/CBF and MAC, enhances salt, drought, and cold tolerance in rice. A variant of one of ERF family genes, Sub1A-1, confers immersion tolerance to lowland rice. These findings and their exploitation will hold promise for engineering breeding to protect crop plants from certain abiotic stresses.

  9. Phytohormones and their metabolic engineering for abiotic stress tolerance in crop plants

    Institute of Scientific and Technical Information of China (English)

    Shabir H.Wani; Vinay Kumar; Varsha Shriram; Saroj Kumar Sah

    2016-01-01

    Abiotic stresses including drought,salinity,heat,cold,flooding,and ultraviolet radiation causes crop losses worldwide.In recent times,preventing these crop losses and producing more food and feed to meet the demands of ever-increasing human populations have gained unprecedented importance.However,the proportion of agricultural lands facing multiple abiotic stresses is expected only to rise under a changing global climate fueled by anthropogenic activities.Identifying the mechanisms developed and deployed by plants to counteract abiotic stresses and maintain their growth and survival under harsh conditions thus holds great significance.Recent investigations have shown that phytohormones,including the classical auxins,cytokinins,ethylene,and gibberellins,and newer members including brassinosteroids,jasmonates,and strigolactones may prove to be important metabolic engineering targets for producing abiotic stress-tolerant crop plants.In this review,we summarize and critically assess the roles that phytohormones play in plant growth and development and abiotic stress tolerance,besides their engineering for conferring abiotic stress tolerance in transgenic crops.We also describe recent successes in identifying the roles of phytohormones under stressful conditions.We conclude by describing the recent progress and future prospects including limitations and challenges of phytohormone engineering for inducing abiotic stress tolerance in crop plants.

  10. Phytohormones and their metabolic engineering for abiotic stress tolerance in crop plants

    Directory of Open Access Journals (Sweden)

    Shabir H. Wani

    2016-06-01

    Full Text Available Abiotic stresses including drought, salinity, heat, cold, flooding, and ultraviolet radiation causes crop losses worldwide. In recent times, preventing these crop losses and producing more food and feed to meet the demands of ever-increasing human populations have gained unprecedented importance. However, the proportion of agricultural lands facing multiple abiotic stresses is expected only to rise under a changing global climate fueled by anthropogenic activities. Identifying the mechanisms developed and deployed by plants to counteract abiotic stresses and maintain their growth and survival under harsh conditions thus holds great significance. Recent investigations have shown that phytohormones, including the classical auxins, cytokinins, ethylene, and gibberellins, and newer members including brassinosteroids, jasmonates, and strigolactones may prove to be important metabolic engineering targets for producing abiotic stress-tolerant crop plants. In this review, we summarize and critically assess the roles that phytohormones play in plant growth and development and abiotic stress tolerance, besides their engineering for conferring abiotic stress tolerance in transgenic crops. We also describe recent successes in identifying the roles of phytohormones under stressful conditions. We conclude by describing the recent progress and future prospects including limitations and challenges of phytohormone engineering for inducing abiotic stress tolerance in crop plants.

  11. Phytohormones and their metabolic engineering for abiotic stress tolerance in crop plants

    Institute of Scientific and Technical Information of China (English)

    Shabir H. Wani; Vinay Kumar; Varsha Shriram; Saroj Kumar Sah

    2016-01-01

    Abiotic stresses including drought, salinity, heat, cold, flooding, and ultraviolet radiation causes crop losses worldwide. In recent times, preventing these crop losses and producing more food and feed to meet the demands of ever-increasing human populations have gained unprecedented importance. However, the proportion of agricultural lands facing multiple abiotic stresses is expected only to rise under a changing global climate fueled by anthropogenic activities. Identifying the mechanisms developed and deployed by plants to counteract abiotic stresses and maintain their growth and survival under harsh conditions thus holds great significance. Recent investigations have shown that phytohormones, including the classical auxins, cytokinins, ethylene, and gibberellins, and newer members including brassinosteroids, jasmonates, and strigolactones may prove to be important metabolic engineering targets for producing abiotic stress-tolerant crop plants. In this review, we summarize and critically assess the roles that phytohormones play in plant growth and development and abiotic stress tolerance, besides their engineering for conferring abiotic stress tolerance in transgenic crops. We also describe recent successes in identifying the roles of phytohormones under stressful conditions. We conclude by describing the recent progress and future prospects including limitations and challenges of phytohormone engineering for inducing abiotic stress tolerance in crop plants.

  12. Hydrogen sulfide regulates abiotic stress tolerance and biotic stress resistance in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Haitao Shi; Tiantian Ye; Ning Han; Hongwu Bian; Xiaodong Liu; Zhulong Chan

    2015-01-01

    Hydrogen sulfide (H2S) is an important gaseous molecule in various plant developmental processes and plant stress responses. In this study, the transgenic Arabidopsis thaliana plants with modulated expressions of two cysteine desulfhydrases, and exogenous H2S donor (sodium hydrosulfide, NaHS) and H2S scavenger (hypotaurine, HT) pre-treated plants were used to dissect the involvement of H2S in plant stress responses. The cysteine desulfhydrases overexpressing plants and NaHS pre-treated plants exhibited higher endogenous H2S level and improved abiotic stress tolerance and biotic stress resistance, while cysteine desulfhydrases knockdown plants and HT pre-treated plants displayed lower endogenous H2S level and decreased stress resistance. Moreover, H2S upregulated the transcripts of multiple abiotic and biotic stress-related genes, and inhibited reactive oxygen species (ROS) accumulation. Interest-ingly, MIR393-mediated auxin signaling including MIR393a/b and their target genes (TIR1, AFB1, AFB2, and AFB3) was transcrip-tional y regulated by H2S, and was related with H2S-induced antibacterial resistance. Moreover, H2S regulated 50 carbon metabolites including amino acids, organic acids, sugars, sugar alcohols, and aromatic amines. Taken together, these results indicated that cysteine desulfhydrase and H2S conferred abiotic stress tolerance and biotic stress resistance, via affecting the stress-related gene expressions, ROS metabolism, metabolic homeostasis, and MIR393-targeted auxin receptors.

  13. Hydrogen sulfide regulates abiotic stress tolerance and biotic stress resistance in Arabidopsis.

    Science.gov (United States)

    Shi, Haitao; Ye, Tiantian; Han, Ning; Bian, Hongwu; Liu, Xiaodong; Chan, Zhulong

    2015-07-01

    Hydrogen sulfide (H2S) is an important gaseous molecule in various plant developmental processes and plant stress responses. In this study, the transgenic Arabidopsis thaliana plants with modulated expressions of two cysteine desulfhydrases, and exogenous H2S donor (sodium hydrosulfide, NaHS) and H2S scavenger (hypotaurine, HT) pre-treated plants were used to dissect the involvement of H2S in plant stress responses. The cysteine desulfhydrases overexpressing plants and NaHS pre-treated plants exhibited higher endogenous H2S level and improved abiotic stress tolerance and biotic stress resistance, while cysteine desulfhydrases knockdown plants and HT pre-treated plants displayed lower endogenous H2S level and decreased stress resistance. Moreover, H2S upregulated the transcripts of multiple abiotic and biotic stress-related genes, and inhibited reactive oxygen species (ROS) accumulation. Interestingly, MIR393-mediated auxin signaling including MIR393a/b and their target genes (TIR1, AFB1, AFB2, and AFB3) was transcriptionally regulated by H2S, and was related with H2S-induced antibacterial resistance. Moreover, H2S regulated 50 carbon metabolites including amino acids, organic acids, sugars, sugar alcohols, and aromatic amines. Taken together, these results indicated that cysteine desulfhydrase and H2S conferred abiotic stress tolerance and biotic stress resistance, via affecting the stress-related gene expressions, ROS metabolism, metabolic homeostasis, and MIR393-targeted auxin receptors.

  14. The effects of bacterial volatile emissions on plant abiotic stress tolerance

    Directory of Open Access Journals (Sweden)

    Xiao-Min eLiu

    2015-09-01

    Full Text Available Plant growth-promoting rhizobacteria (PGPR are beneficial plant symbionts that have been successfully used in agriculture to increase seedling emergence, plant weight, crop yield, and disease resistance. Some PGPR strains release volatile organic compounds (VOCs that can directly and/or indirectly mediate increases in plant biomass, disease resistance, and abiotic stress tolerance. This mini-review focuses on the enhancement of plant abiotic stress tolerance by bacterial VOCs. The review considers how PGPR VOCs induce tolerance to salinity and drought stress and also how they improve sulfur and iron nutrition in plants. The potential complexities in evaluating the effects of PGPR VOCs are also discussed.

  15. Regulatory roles of serotonin and melatonin in abiotic stress tolerance in plants.

    Science.gov (United States)

    Kaur, Harmeet; Mukherjee, Soumya; Baluska, Frantisek; Bhatla, Satish C

    2015-01-01

    Understanding the physiological and biochemical basis of abiotic stress tolerance in plants has always been one of the major aspects of research aiming to enhance plant productivity in arid and semi-arid cultivated lands all over the world. Growth of stress-tolerant transgenic crops and associated agricultural benefits through increased productivity, and related ethical issues, are also the major concerns of current research in various laboratories. Interesting data on the regulation of abiotic stress tolerance in plants by serotonin and melatonin has accumulated in the recent past. These two indoleamines possess antioxidative and growth-inducing properties, thus proving beneficial for stress acclimatization. Present review shall focus on the modes of serotonin and melatonin-induced regulation of abiotic stress tolerance in plants. Complex molecular interactions of serotonin and auxin-responsive genes have suggested their antagonistic nature. Data from genomic and metabolomic analyses of melatonin-induced abiotic stress signaling have lead to an understanding of the regulation of stress tolerance through the modulation of transcription factors, enzymes and various signaling molecules. Melatonin, nitric oxide (NO) and calmodulin interactions have provided new avenues for research on the molecular aspects of stress physiology in plants. Investigations on the characterization of receptors associated with serotonin and melatonin responses, are yet to be undertaken in plants. Patenting of biotechnological inventions pertaining to serotonin and melatonin formulations (through soil application or foliar spray) are expected to be some of the possible ways to regulate abiotic stress tolerance in plants. The present review, thus, summarizes the regulatory roles of serotonin and melatonin in modulating the signaling events accompanying abiotic stress in plants.

  16. Unraveling the role of fungal symbionts in plant abiotic stress tolerance.

    Science.gov (United States)

    Singh, Lamabam Peter; Gill, Sarvajeet Singh; Tuteja, Narendra

    2011-02-01

    Fungal symbionts have been found associated with every plant studied in natural ecosystem, where they colonize and reside entirely in the internal tissues of their host plant or partially. Fungal endophytes can express/form a range of different lifestyle/relationships with different host including symbiotic, mutualistic, commensalistic and parasitic in response to host genotype and environmental factors. In mutualistic association fungal endophyte can enhance growth, increase reproductive success and confer biotic and abiotic stress tolerance to its host plant. Since abiotic stress such as, drought, high soil salinity, heat, cold, oxidative stress, heavy metal toxicity is the common adverse environmental conditions that affect and limit crop productivity worldwide. It may be a promising alternative strategy to exploit fungal endophytes to overcome the limitations to crop production brought by abiotic stress. There is increasing interest in developing the potential biotechnological applications of fungal endophytes for improving plant stress tolerance and sustainable production of food crops. Here we have described the fungal symbioses, fungal symbionts and their role in abiotic stress tolerance. A putative mechanism of stress tolerance by symbionts has also been covered.

  17. Abiotic Stress Tolerance: From Gene Discovery in Model Organisms to Crop Improvement

    Institute of Scientific and Technical Information of China (English)

    Ray Bressan; Hans Bohnert; Jian-Kang Zhu

    2009-01-01

    Productive and sustainable agriculture necessitates growing plants in sub-optimal environments with less input of precious resources such as fresh water. For a better understanding and rapid improvement of abiotic stress tolerance, it is important to link physiological and biochemical work to molecular studies in genetically tractable model organisms. With the use of several technologies for the discovery of stress tolerance genes and their appropriate alleles,transgenic approaches to improving stress tolerance in crops remarkably parallels breeding principles with a greatly expanded germplasm base and will succeed eventually.

  18. A Central Role for Thiols in Plant Tolerance to Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Lyuben Zagorchev

    2013-04-01

    Full Text Available Abiotic stress poses major problems to agriculture and increasing efforts are being made to understand plant stress response and tolerance mechanisms and to develop new tools that underpin successful agriculture. However, the molecular mechanisms of plant stress tolerance are not fully understood, and the data available is incomplete and sometimes contradictory. Here, we review the significance of protein and non-protein thiol compounds in relation to plant tolerance of abiotic stress. First, the roles of the amino acids cysteine and methionine, are discussed, followed by an extensive discussion of the low-molecular-weight tripeptide, thiol glutathione, which plays a central part in plant stress response and oxidative signalling and of glutathione-related enzymes, including those involved in the biosynthesis of non-protein thiol compounds. Special attention is given to the glutathione redox state, to phytochelatins and to the role of glutathione in the regulation of the cell cycle. The protein thiol section focuses on glutaredoxins and thioredoxins, proteins with oxidoreductase activity, which are involved in protein glutathionylation. The review concludes with a brief overview of and future perspectives for the involvement of plant thiols in abiotic stress tolerance.

  19. Coordinated Actions of Glyoxalase and Antioxidant Defense Systems in Conferring Abiotic Stress Tolerance in Plants

    Directory of Open Access Journals (Sweden)

    Mirza Hasanuzzaman

    2017-01-01

    Full Text Available Being sessile organisms, plants are frequently exposed to various environmental stresses that cause several physiological disorders and even death. Oxidative stress is one of the common consequences of abiotic stress in plants, which is caused by excess generation of reactive oxygen species (ROS. Sometimes ROS production exceeds the capacity of antioxidant defense systems, which leads to oxidative stress. In line with ROS, plants also produce a high amount of methylglyoxal (MG, which is an α-oxoaldehyde compound, highly reactive, cytotoxic, and produced via different enzymatic and non-enzymatic reactions. This MG can impair cells or cell components and can even destroy DNA or cause mutation. Under stress conditions, MG concentration in plants can be increased 2- to 6-fold compared with normal conditions depending on the plant species. However, plants have a system developed to detoxify this MG consisting of two major enzymes: glyoxalase I (Gly I and glyoxalase II (Gly II, and hence known as the glyoxalase system. Recently, a novel glyoxalase enzyme, named glyoxalase III (Gly III, has been detected in plants, providing a shorter pathway for MG detoxification, which is also a signpost in the research of abiotic stress tolerance. Glutathione (GSH acts as a co-factor for this system. Therefore, this system not only detoxifies MG but also plays a role in maintaining GSH homeostasis and subsequent ROS detoxification. Upregulation of both Gly I and Gly II as well as their overexpression in plant species showed enhanced tolerance to various abiotic stresses including salinity, drought, metal toxicity, and extreme temperature. In the past few decades, a considerable amount of reports have indicated that both antioxidant defense and glyoxalase systems have strong interactions in conferring abiotic stress tolerance in plants through the detoxification of ROS and MG. In this review, we will focus on the mechanisms of these interactions and the coordinated

  20. Coordinated Actions of Glyoxalase and Antioxidant Defense Systems in Conferring Abiotic Stress Tolerance in Plants

    Science.gov (United States)

    Hasanuzzaman, Mirza; Nahar, Kamrun; Hossain, Md. Shahadat; Mahmud, Jubayer Al; Rahman, Anisur; Inafuku, Masashi; Oku, Hirosuke; Fujita, Masayuki

    2017-01-01

    Being sessile organisms, plants are frequently exposed to various environmental stresses that cause several physiological disorders and even death. Oxidative stress is one of the common consequences of abiotic stress in plants, which is caused by excess generation of reactive oxygen species (ROS). Sometimes ROS production exceeds the capacity of antioxidant defense systems, which leads to oxidative stress. In line with ROS, plants also produce a high amount of methylglyoxal (MG), which is an α-oxoaldehyde compound, highly reactive, cytotoxic, and produced via different enzymatic and non-enzymatic reactions. This MG can impair cells or cell components and can even destroy DNA or cause mutation. Under stress conditions, MG concentration in plants can be increased 2- to 6-fold compared with normal conditions depending on the plant species. However, plants have a system developed to detoxify this MG consisting of two major enzymes: glyoxalase I (Gly I) and glyoxalase II (Gly II), and hence known as the glyoxalase system. Recently, a novel glyoxalase enzyme, named glyoxalase III (Gly III), has been detected in plants, providing a shorter pathway for MG detoxification, which is also a signpost in the research of abiotic stress tolerance. Glutathione (GSH) acts as a co-factor for this system. Therefore, this system not only detoxifies MG but also plays a role in maintaining GSH homeostasis and subsequent ROS detoxification. Upregulation of both Gly I and Gly II as well as their overexpression in plant species showed enhanced tolerance to various abiotic stresses including salinity, drought, metal toxicity, and extreme temperature. In the past few decades, a considerable amount of reports have indicated that both antioxidant defense and glyoxalase systems have strong interactions in conferring abiotic stress tolerance in plants through the detoxification of ROS and MG. In this review, we will focus on the mechanisms of these interactions and the coordinated action of

  1. Transgenic alfalfa plants expressing the sweetpotato Orange gene exhibit enhanced abiotic stress tolerance.

    Directory of Open Access Journals (Sweden)

    Zhi Wang

    Full Text Available Alfalfa (Medicago sativa L., a perennial forage crop with high nutritional content, is widely distributed in various environments worldwide. We recently demonstrated that the sweetpotato Orange gene (IbOr is involved in increasing carotenoid accumulation and enhancing resistance to multiple abiotic stresses. In this study, in an effort to improve the nutritional quality and environmental stress tolerance of alfalfa, we transferred the IbOr gene into alfalfa (cv. Xinjiang Daye under the control of an oxidative stress-inducible peroxidase (SWPA2 promoter through Agrobacterium tumefaciens-mediated transformation. Among the 11 transgenic alfalfa lines (referred to as SOR plants, three lines (SOR2, SOR3, and SOR8 selected based on their IbOr transcript levels were examined for their tolerance to methyl viologen (MV-induced oxidative stress in a leaf disc assay. The SOR plants exhibited less damage in response to MV-mediated oxidative stress and salt stress than non-transgenic plants. The SOR plants also exhibited enhanced tolerance to drought stress, along with higher total carotenoid levels. The results suggest that SOR alfalfa plants would be useful as forage crops with improved nutritional value and increased tolerance to multiple abiotic stresses, which would enhance the development of sustainable agriculture on marginal lands.

  2. Abiotic stress tolerance and competition-related traits underlie phylogenetic clustering in soil bacterial communities.

    Science.gov (United States)

    Goberna, Marta; Navarro-Cano, Jose A; Valiente-Banuet, Alfonso; García, Carlos; Verdú, Miguel

    2014-10-01

    Soil bacteria typically coexist with close relatives generating widespread phylogenetic clustering. This has been ascribed to the abiotic filtering of organisms with shared ecological tolerances. Recent theoretical developments suggest that competition can also explain the phylogenetic similarity of coexisting organisms by excluding large low-competitive clades. We propose that combining the environmental patterns of traits associated with abiotic stress tolerances or competitive abilities with phylogeny and abundance data, can help discern between abiotic and biotic mechanisms underlying the coexistence of phylogenetically related bacteria. We applied this framework in a model system composed of interspersed habitats of highly contrasted productivity and comparatively dominated by biotic and abiotic processes, i.e. the plant patch-gap mosaic typical of drylands. We examined the distribution of 15 traits and 3290 bacterial taxa in 28 plots. Communities showed a marked functional response to the environment. Conserved traits related to environmental stress tolerance (e.g. desiccation, formation of resistant structures) were differentially selected in either habitat, while competition related traits (e.g. organic C consumption, formation of nutrient-scavenging structures) prevailed under high resource availability. Phylogenetic clustering was stronger in habitats dominated by biotic filtering, suggesting that competitive exclusion of large clades might underlie the ecological similarity of co-occurring soil bacteria.

  3. Metabolomics as a Tool to Investigate Abiotic Stress Tolerance in Plants

    Directory of Open Access Journals (Sweden)

    Aurelio Gómez-Cadenas

    2013-03-01

    Full Text Available Metabolites reflect the integration of gene expression, protein interaction and other different regulatory processes and are therefore closer to the phenotype than mRNA transcripts or proteins alone. Amongst all –omics technologies, metabolomics is the most transversal and can be applied to different organisms with little or no modifications. It has been successfully applied to the study of molecular phenotypes of plants in response to abiotic stress in order to find particular patterns associated to stress tolerance. These studies have highlighted the essential involvement of primary metabolites: sugars, amino acids and Krebs cycle intermediates as direct markers of photosynthetic dysfunction as well as effectors of osmotic readjustment. On the contrary, secondary metabolites are more specific of genera and species and respond to particular stress conditions as antioxidants, Reactive Oxygen Species (ROS scavengers, coenzymes, UV and excess radiation screen and also as regulatory molecules. In addition, the induction of secondary metabolites by several abiotic stress conditions could also be an effective mechanism of cross-protection against biotic threats, providing a link between abiotic and biotic stress responses. Moreover, the presence/absence and relative accumulation of certain metabolites along with gene expression data provides accurate markers (mQTL or MWAS for tolerant crop selection in breeding programs.

  4. ABA Inducible Rice Protein Phosphatase 2C Confers ABA Insensitivity and Abiotic Stress Tolerance in Arabidopsis

    Science.gov (United States)

    Singh, Amarjeet; Jha, Saroj K.; Bagri, Jayram; Pandey, Girdhar K.

    2015-01-01

    Arabidopsis PP2C belonging to group A have been extensively worked out and known to negatively regulate ABA signaling. However, rice (Oryza sativa) orthologs of Arabidopsis group A PP2C are scarcely characterized functionally. We have identified a group A PP2C from rice (OsPP108), which is highly inducible under ABA, salt and drought stresses and localized predominantly in the nucleus. Genetic analysis revealed that Arabidopsis plants overexpressing OsPP108 are highly insensitive to ABA and tolerant to high salt and mannitol stresses during seed germination, root growth and overall seedling growth. At adult stage, OsPP108 overexpression leads to high tolerance to salt, mannitol and drought stresses with far better physiological parameters such as water loss, fresh weight, chlorophyll content and photosynthetic potential (Fv/Fm) in transgenic Arabidopsis plants. Expression profile of various stress marker genes in OsPP108 overexpressing plants revealed interplay of ABA dependent and independent pathway for abiotic stress tolerance. Overall, this study has identified a potential rice group A PP2C, which regulates ABA signaling negatively and abiotic stress signaling positively. Transgenic rice plants overexpressing this gene might provide an answer to the problem of low crop yield and productivity during adverse environmental conditions. PMID:25886365

  5. DREB1/CBF transcription factors: their structure, function and role in abiotic stress tolerance in plants

    Indian Academy of Sciences (India)

    M. Akhtar; A. Jaiswal; G. Taj; J. P. Jaiswal; M. I. Qureshi; N. K. Singh

    2012-12-01

    Drought, high salinity and low temperature are major abiotic stresses that influence survival, productivity and geographical distribution of many important crops across the globe. Plants respond to these environmental challenges via physiological, cellular and molecular processes, which results in adjusted metabolic and structural alterations. The dehydration-responsive-element-binding (DREB) protein / C-repeat binding factors (CBFs) belong to APETALA2 (AP2) family transcription factors that bind to DRE/CRT cis-element and regulate the expression of stress-responsive genes. DREB1/CBF genes, therefore, play an important role in increasing stress tolerance in plants and their deployment using transgenic technology seems to be a potential alternative in management of abiotic stresses in crop plants. This review is mainly focussed on the structural characteristics as well as transcriptional regulation of gene expression in response to various abiotic stresses, with particular emphasis on the role of DREB1/CBF regulon in stress-responsive gene expression. The recent progress related to genetic engineering of DREB1/CBF transcription factors in various crops and model plants is also summarized.

  6. Increasing ascorbate levels in crops to enhance human nutrition and plant abiotic stress tolerance.

    Science.gov (United States)

    Macknight, Richard C; Laing, William A; Bulley, Sean M; Broad, Ronan C; Johnson, Alexander At; Hellens, Roger P

    2017-02-20

    Ascorbate (or vitamin C) is an essential human micronutrient predominantly obtained from plants. In addition to preventing scurvy, it is now known to have broader roles in human health, for example as a cofactor for enzymes involved in epigenetic programming and as regulator of cellular iron uptake. Furthermore, ascorbate is the major antioxidant in plants and underpins many environmentally induced abiotic stress responses. Biotechnological approaches to enhance the ascorbate content of crops therefore have potential to improve both human health and abiotic stress tolerance of crops. Identifying the genetic basis of ascorbate variation between plant varieties and discovering how some 'super fruits' accumulate extremely high levels of ascorbate should reveal new ways to more effectively manipulate the production of ascorbate in crops.

  7. ATHB17 enhances stress tolerance by coordinating photosynthesis associated nuclear gene and ATSIG5 expression in response to abiotic stress

    Science.gov (United States)

    Zhao, Ping; Cui, Rong; Xu, Ping; Wu, Jie; Mao, Jie-Li; Chen, Yu; Zhou, Cong-Zhao; Yu, Lin-Hui; Xiang, Cheng-Bin

    2017-01-01

    Photosynthesis is sensitive to environmental stress and must be efficiently modulated in response to abiotic stress. However, the underlying mechanisms are not well understood. Here we report that ARABIDOPSIS THALIANA HOMEOBOX 17 (ATHB17), an Arabidopsis HD-Zip transcription factor, regulated the expression of a number of photosynthesis associated nuclear genes (PhANGs) involved in the light reaction and ATSIG5 in response to abiotic stress. ATHB17 was responsive to ABA and multiple stress treatments. ATHB17-overexpressing plants displayed enhanced stress tolerance, whereas its knockout mutant was more sensitive compared to the wild type. Through RNA-seq and quantitative real-time reverse transcription PCR (qRT-PCR) analysis, we found that ATHB17 did not affect the expression of many known stress-responsive marker genes. Interestingly, we found that ATHB17 down-regulated many PhANGs and could directly modulate the expression of several PhANGs by binding to their promoters. Moreover, we identified ATSIG5, encoding a plastid sigma factor, as one of the target genes of ATHB17. Loss of ATSIG5 reduced salt tolerance while overexpression of ATSIG5 enhanced salt tolerance, similar to that of ATHB17. ATHB17 can positively modulate the expression of many plastid encoded genes (PEGs) through regulation of ATSIG5. Taken together, our results suggest that ATHB17 may play an important role in protecting plants by adjusting expression of PhANGs and PEGs in response to abiotic stresses. PMID:28358040

  8. Soybean NAC transcription factors promote abiotic stress tolerance and lateral root formation in transgenic plants.

    Science.gov (United States)

    Hao, Yu-Jun; Wei, Wei; Song, Qing-Xin; Chen, Hao-Wei; Zhang, Yu-Qin; Wang, Fang; Zou, Hong-Feng; Lei, Gang; Tian, Ai-Guo; Zhang, Wan-Ke; Ma, Biao; Zhang, Jin-Song; Chen, Shou-Yi

    2011-10-01

    NAC transcription factors play important roles in plant growth, development and stress responses. Previously, we identified multiple NAC genes in soybean (Glycine max). Here, we identify the roles of two genes, GmNAC11 and GmNAC20, in stress responses and other processes. The two genes were differentially induced by multiple abiotic stresses and plant hormones, and their transcripts were abundant in roots and cotyledons. Both genes encoded proteins that localized to the nucleus and bound to the core DNA sequence CGT[G/A]. In the protoplast assay system, GmNAC11 acts as a transcriptional activator, whereas GmNAC20 functions as a mild repressor; however, the C-terminal end of GmANC20 has transcriptional activation activity. Over-expression of GmNAC20 enhances salt and freezing tolerance in transgenic Arabidopsis plants; however, GmNAC11 over-expression only improves salt tolerance. Over-expression of GmNAC20 also promotes lateral root formation. GmNAC20 may regulate stress tolerance through activation of the DREB/CBF-COR pathway, and may control lateral root development by altering auxin signaling-related genes. GmNAC11 probably regulates DREB1A and other stress-related genes. The roles of the two GmNAC genes in stress tolerance were further analyzed in soybean transgenic hairy roots. These results provide a basis for genetic manipulation to improve the agronomic traits of important crops.

  9. Cross-tolerance to biotic and abiotic stresses in plants: a focus on resistance to aphid infestation.

    Science.gov (United States)

    Foyer, Christine H; Rasool, Brwa; Davey, Jack W; Hancock, Robert D

    2016-03-01

    Plants co-evolved with an enormous variety of microbial pathogens and insect herbivores under daily and seasonal variations in abiotic environmental conditions. Hence, plant cells display a high capacity to respond to diverse stresses through a flexible and finely balanced response network that involves components such as reduction-oxidation (redox) signalling pathways, stress hormones and growth regulators, as well as calcium and protein kinase cascades. Biotic and abiotic stress responses use common signals, pathways and triggers leading to cross-tolerance phenomena, whereby exposure to one type of stress can activate plant responses that facilitate tolerance to several different types of stress. While the acclimation mechanisms and adaptive responses that facilitate responses to single biotic and abiotic stresses have been extensively characterized, relatively little information is available on the dynamic aspects of combined biotic/abiotic stress response. In this review, we consider how the abiotic environment influences plant responses to attack by phloem-feeding aphids. Unravelling the signalling cascades that underpin cross-tolerance to biotic and abiotic stresses will allow the identification of new targets for increasing environmental resilience in crops.

  10. Transgenic alfalfa plants expressing AtNDPK2 exhibit increased growth and tolerance to abiotic stresses.

    Science.gov (United States)

    Wang, Zhi; Li, Hongbing; Ke, Qingbo; Jeong, Jae Cheol; Lee, Haeng-Soon; Xu, Bingcheng; Deng, Xi-Ping; Lim, Yong Pyo; Kwak, Sang-Soo

    2014-11-01

    In this study, we generated and evaluated transgenic alfalfa plants (Medicago sativa L. cv. Xinjiang Daye) expressing the Arabidopsis nucleoside diphosphate kinase 2 (AtNDPK2) gene under the control of the oxidative stress-inducible SWPA2 promoter (referred to as SN plants) to develop plants with enhanced tolerance to various abiotic stresses. We selected two SN plants (SN4 and SN7) according to the expression levels of AtNDPK2 and the enzyme activity of NDPK in response to methyl viologen (MV)-mediated oxidative stress treatment using leaf discs for further characterization. SN plants showed enhanced tolerance to high temperature, NaCl, and drought stress on the whole-plant level. When the plants were subjected to high temperature treatment (42 °C for 24 h), the non-transgenic (NT) plants were severely wilted, whereas the SN plants were not affected because they maintained high relative water and chlorophyll contents. The SN plants also showed significantly higher tolerance to 250 mM NaCl and water stress treatment than the NT plants. In addition, the SN plants exhibited better plant growth through increased expression of auxin-related indole acetic acid (IAA) genes (MsIAA3, MsIAA5, MsIAA6, MsIAA7, and MsIAA16) under normal growth conditions compared to NT plants. The results suggest that induced overexpression of AtNDPK2 in alfalfa will be useful for increasing biomass production under various abiotic stress conditions.

  11. Methylglyoxal: An Emerging Signaling Molecule in Plant Abiotic Stress Responses and Tolerance

    Science.gov (United States)

    Hoque, Tahsina S.; Hossain, Mohammad A.; Mostofa, Mohammad G.; Burritt, David J.; Fujita, Masayuki; Tran, Lam-Son P.

    2016-01-01

    The oxygenated short aldehyde methylglyoxal (MG) is produced in plants as a by-product of a number of metabolic reactions, including elimination of phosphate groups from glycolysis intermediates dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. MG is mostly detoxified by the combined actions of the enzymes glyoxalase I and glyoxalase II that together with glutathione make up the glyoxalase system. Under normal growth conditions, basal levels of MG remain low in plants; however, when plants are exposed to abiotic stress, MG can accumulate to much higher levels. Stress-induced MG functions as a toxic molecule, inhibiting different developmental processes, including seed germination, photosynthesis and root growth, whereas MG, at low levels, acts as an important signaling molecule, involved in regulating diverse events, such as cell proliferation and survival, control of the redox status of cells, and many other aspects of general metabolism and cellular homeostases. MG can modulate plant stress responses by regulating stomatal opening and closure, the production of reactive oxygen species, cytosolic calcium ion concentrations, the activation of inward rectifying potassium channels and the expression of many stress-responsive genes. MG appears to play important roles in signal transduction by transmitting and amplifying cellular signals and functions that promote adaptation of plants growing under adverse environmental conditions. Thus, MG is now considered as a potential biochemical marker for plant abiotic stress tolerance, and is receiving considerable attention by the scientific community. In this review, we will summarize recent findings regarding MG metabolism in plants under abiotic stress, and evaluate the concept of MG signaling. In addition, we will demonstrate the importance of giving consideration to MG metabolism and the glyoxalase system, when investigating plant adaptation and responses to various environmental stresses. PMID:27679640

  12. HyPRP1 Gene Suppressed by Multiple Stresses Plays a Negative Role in Abiotic Stress Tolerance in Tomato

    Science.gov (United States)

    Li, Jinhua; Ouyang, Bo; Wang, Taotao; Luo, Zhidan; Yang, Changxian; Li, Hanxia; Sima, Wei; Zhang, Junhong; Ye, Zhibiao

    2016-01-01

    Many hybrid proline-rich protein (HyPRP) genes respond to biotic and abiotic stresses in plants, but little is known about their roles other than as putative cell-wall structural proteins. A HyPRP1 gene encodes a protein with proline-rich domain, and an eight-cysteine motif was identified from our previous microarray experiments on drought-tolerant tomato. In this study, the expression of the HyPRP1 gene in tomato was suppressed under various abiotic stresses, such as drought, high salinity, cold, heat, and oxidative stress. Transgenic functional analysis showed no obvious changes in phenotypes, but enhanced tolerance to various abiotic stresses (e.g., oxidative stress, dehydration, and salinity) was observed in RNAi transgenic plants. Interestingly, several SO2 detoxification-related enzymes, including sulfite oxidase, ferredoxins (Fds), and methionine sulfoxide reductase A (Msr A), were revealed in HyPRP1-interacting proteins identified by Yeast Two-Hybrid screening. More sulfates and transcripts of Msr A and Fds were accumulated in HyPRP1 knockdown lines when wild-type plants were exposed to SO2 gas. Our findings illustrate that the tomato HyPRP1 is a negative regulator of salt and oxidative stresses and is probably involved in sulfite metabolism. PMID:27446190

  13. Sugar beet M14 glyoxalase I gene can enhance plant tolerance to abiotic stresses.

    Science.gov (United States)

    Wu, Chuan; Ma, Chunquan; Pan, Yu; Gong, Shilong; Zhao, Chenxi; Chen, Sixue; Li, Haiying

    2013-05-01

    Glyoxalase I is the first enzyme of the glyoxalase system that can detoxify methylglyoxal, a cytotoxic compound increased rapidly under stress conditions. Here we report cloning and characterization of a glyoxalase I from sugar beet M14 line (an interspecific hybrid between a wild species Beta corolliflora Zoss and a cultivated species B. vulgaris L). The full-length gene BvM14-glyoxalase I has 1,449 bp in length with an open reading frame of 1,065 bp encoding 354 amino acids. Sequence analysis shows the conserved glyoxalase I domains, metal and glutathione binding sites and secondary structure (α-helixes and β-sheets). The BvM14-glyoxalase I gene was ubiquitously expressed in different tissues of sugar beet M14 line and up-regulated in response to salt, mannitol and oxidative stresses. Heterologous expression of BvM14-glyoxalase I could increase E. coli tolerance to methylglyoxal. Transgenic tobacco plants constitutively expressing BvM14-glyoxalase I were generated. Both leaf discs and seedlings showed significant tolerance to methylglyoxal, salt, mannitol and H2O2. These results suggest an important role of BvM14-glyoxalase I in cellular detoxification and tolerance to abiotic stresses.

  14. Abiotic Stress Tolerance of Charophyte Green Algae: New Challenges for Omics Techniques.

    Science.gov (United States)

    Holzinger, Andreas; Pichrtová, Martina

    2016-01-01

    Charophyte green algae are a paraphyletic group of freshwater and terrestrial green algae, comprising the classes of Chlorokybophyceae, Coleochaetophyceae, Klebsormidiophyceae, Zygnematophyceae, Mesostigmatophyceae, and Charo- phyceae. Zygnematophyceae (Conjugating green algae) are considered to be closest algal relatives to land plants (Embryophyta). Therefore, they are ideal model organisms for studying stress tolerance mechanisms connected with transition to land, one of the most important events in plant evolution and the Earth's history. In Zygnematophyceae, but also in Coleochaetophyceae, Chlorokybophyceae, and Klebsormidiophyceae terrestrial members are found which are frequently exposed to naturally occurring abiotic stress scenarios like desiccation, freezing and high photosynthetic active (PAR) as well as ultraviolet (UV) irradiation. Here, we summarize current knowledge about various stress tolerance mechanisms including insight provided by pioneer transcriptomic and proteomic studies. While formation of dormant spores is a typical strategy of freshwater classes, true terrestrial groups are stress tolerant in vegetative state. Aggregation of cells, flexible cell walls, mucilage production and accumulation of osmotically active compounds are the most common desiccation tolerance strategies. In addition, high photophysiological plasticity and accumulation of UV-screening compounds are important protective mechanisms in conditions with high irradiation. Now a shift from classical chemical analysis to next-generation genome sequencing, gene reconstruction and annotation, genome-scale molecular analysis using omics technologies followed by computer-assisted analysis will give new insights in a systems biology approach. For example, changes in transcriptome and role of phytohormone signaling in Klebsormidium during desiccation were recently described. Application of these modern approaches will deeply enhance our understanding of stress reactions in an

  15. Building the crops of tomorrow: advantages of symbiont-based approaches to improving abiotic stress tolerance

    Directory of Open Access Journals (Sweden)

    Devin eColeman-Derr

    2014-06-01

    Full Text Available The exponential growth in world population is feeding a steadily increasing global need for arable farmland, a resource that is already in high demand. This trend has led to increased farming on subprime arid and semi-arid lands, where limited availability of water and a host of environmental stresses often severely reduce crop productivity. The conventional approach to mitigating the abiotic stresses associated with arid climes is to breed for stress-tolerant cultivars, a time and labor intensive venture that often neglects the complex ecological context of the soil environment in which the crop is grown. In recent years, studies have attempted to identify microbial symbionts capable of conferring the same stress-tolerance to their plant hosts, and new developments in genomic technologies have greatly facilitated such research. Here, we highlight many of the advantages of these symbiont-based approaches and argue in favor of the broader recognition of crop species as ecological niches for a diverse community of microorganisms that function in concert with their plant hosts and each other to thrive under fluctuating environmental conditions.

  16. Building the crops of tomorrow: advantages of symbiont-based approaches to improving abiotic stress tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Coleman-Derr, Devin [USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States); Tringe, Susannah G. [USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States)

    2014-06-06

    The exponential growth in world population is feeding a steadily increasing global need for arable farmland, a resource that is already in high demand. This trend has led to increased farming on subprime arid and semi-arid lands, where limited availability of water and a host of environmental stresses often severely reduce crop productivity. The conventional approach to mitigating the abiotic stresses associated with arid climes is to breed for stress-tolerant cultivars, a time and labor intensive venture that often neglects the complex ecological context of the soil environment in which the crop is grown. In recent years, studies have attempted to identify microbial symbionts capable of conferring the same stress-tolerance to their plant hosts, and new developments in genomic technologies have greatly facilitated such research. Here in this paper, we highlight many of the advantages of these symbiont-based approaches and argue in favor of the broader recognition of crop species as ecological niches for a diverse community of microorganisms that function in concert with their plant hosts and each other to thrive under fluctuating environmental conditions

  17. The Alfin-like homeodomain finger protein AL5 suppresses multiple negative factors to confer abiotic stress tolerance in Arabidopsis.

    Science.gov (United States)

    Wei, Wei; Zhang, Yu-Qin; Tao, Jian-Jun; Chen, Hao-Wei; Li, Qing-Tian; Zhang, Wan-Ke; Ma, Biao; Lin, Qing; Zhang, Jin-Song; Chen, Shou-Yi

    2015-03-01

    Plant homeodomain (PHD) finger proteins affect processes of growth and development by changing transcription and reading epigenetic histone modifications, but their functions in abiotic stress responses remain largely unclear. Here we characterized seven Arabidopsis thaliana Alfin1-like PHD finger proteins (ALs) in terms of the responses to abiotic stresses. ALs localized to the nucleus and repressed transcription. Except AL6, all the ALs bound to G-rich elements. Mutations of the amino acids at positions 34 and 35 in AL6 caused loss of ability to bind to G-rich elements. Expression of the AL genes responded differentially to osmotic stress, salt, cold and abscisic acid treatments. AL5-over-expressing plants showed higher tolerance to salt, drought and freezing stress than Col-0. Consistently, al5 mutants showed reduced stress tolerance. We used ChIP-Seq assays to identify eight direct targets of AL5, and found that AL5 binds to the promoter regions of these genes. Knockout mutants of five of these target genes exhibited varying tolerances to stresses. These results indicate that AL5 inhibits multiple signaling pathways to confer stress tolerance. Our study sheds light on mechanisms of AL5-mediated signaling in abiotic stress responses, and provides tools for improvement of stress tolerance in crop plants.

  18. Improved tolerance to various abiotic stresses in transgenic sweet potato (Ipomoea batatas expressing spinach betaine aldehyde dehydrogenase.

    Directory of Open Access Journals (Sweden)

    Weijuan Fan

    Full Text Available Abiotic stresses are critical delimiters for the increased productivity and cultivation expansion of sweet potato (Ipomoea batatas, a root crop with worldwide importance. The increased production of glycine betaine (GB improves plant tolerance to various abiotic stresses without strong phenotypic changes, providing a feasible approach to improve stable yield production under unfavorable conditions. The gene encoding betaine aldehyde dehydrogenase (BADH is involved in the biosynthesis of GB in plants, and the accumulation of GB by the heterologous overexpression of BADH improves abiotic stress tolerance in plants. This study is to improve sweet potato, a GB accumulator, resistant to multiple abiotic stresses by promoted GB biosynthesis. A chloroplastic BADH gene from Spinacia oleracea (SoBADH was introduced into the sweet potato cultivar Sushu-2 via Agrobacterium-mediated transformation. The overexpression of SoBADH in the transgenic sweet potato improved tolerance to various abiotic stresses, including salt, oxidative stress, and low temperature. The increased BADH activity and GB accumulation in the transgenic plant lines under normal and multiple environmental stresses resulted in increased protection against cell damage through the maintenance of cell membrane integrity, stronger photosynthetic activity, reduced reactive oxygen species (ROS production, and induction or activation of ROS scavenging by the increased activity of free radical-scavenging enzymes. The increased proline accumulation and systemic upregulation of many ROS-scavenging genes in stress-treated transgenic plants also indicated that GB accumulation might stimulate the ROS-scavenging system and proline biosynthesis via an integrative mechanism. This study demonstrates that the enhancement of GB biosynthesis in sweet potato is an effective and feasible approach to improve its tolerance to multiple abiotic stresses without causing phenotypic defects. This strategy for trait

  19. Expression of a finger millet transcription factor, EcNAC1, in tobacco confers abiotic stress-tolerance.

    Directory of Open Access Journals (Sweden)

    Venkategowda Ramegowda

    Full Text Available NAC (NAM, ATAF1-2, and CUC2 proteins constitute one of the largest families of plant-specific transcription factors and have been shown to be involved in diverse plant processes including plant growth, development, and stress-tolerance. In this study, a stress-responsive NAC gene, EcNAC1, was isolated from the subtracted stress cDNA library generated from a drought adapted crop, finger millet, and characterized for its role in stress-tolerance. The expression analysis showed that EcNAC1 was highly induced during water-deficit and salt stress. EcNAC1 shares high amino acid similarity with rice genes that have been phylogenetically classified into stress-related NAC genes. Our results demonstrated that tobacco transgenic plants expressing EcNAC1 exhibit tolerance to various abiotic stresses like simulated osmotic stress, by polyethylene glycol (PEG and mannitol, and salinity stress. The transgenic plants also showed enhanced tolerance to methyl-viologen (MV induced oxidative stress. Reduced levels of reactive oxygen species (ROS and ROS-induced damage were noticed in pot grown transgenic lines under water-deficit and natural high light conditions. Root growth under stress and recovery growth after stress alleviation was more in transgenic plants. Many stress-responsive genes were found to be up-regulated in transgenic lines expressing EcNAC1. Our results suggest that EcNAC1 overexpression confers tolerance against abiotic stress in susceptible species, tobacco.

  20. In Vitro Screening for Abiotic Stress Tolerance in Potent Biocontrol and Plant Growth Promoting Strains of Pseudomonas and Bacillus spp.

    Directory of Open Access Journals (Sweden)

    G. Praveen Kumar

    2014-01-01

    Full Text Available Plant growth promoting rhizobacteria (PGPR has been identified as a group of microbes that are used for plant growth enhancement and biocontrol for management of plant diseases. The inconsistency in performance of these bacteria from laboratory to field conditions is compounded due to the prevailing abiotic stresses in the field. Therefore, selection of bacterial strains with tolerance to abiotic stresses would benefit the end-user by successful establishment of the strain for showing desired effects. In this study we attempted to isolate and identify strains of Bacillus and Pseudomonas spp. with stress tolerance and proven ability to inhibit the growth of potential phytopathogenic fungi. Screening of bacterial strains for high temperature (50°C, salinity (7% NaCl, and drought (−1.2 MPa showed that stress tolerance was pronounced less in Pseudomonas isolates than in Bacillus strains. The reason behind this could be the formation of endospores by Bacillus isolates. Tolerance to drought was high in Pseudomonas strains than the other two stresses. Three strains, P8, P20 and P21 showed both salinity and temperature tolerance. P59 strain possessed promising antagonistic activity and drought tolerance. The magnitude of antagonism shown by Bacillus isolates was also higher when compared to Pseudomonas strains. To conclude, identification of microbial candidate strains with stress tolerance and other added characteristic features would help the end-user obtain the desired beneficial effects.

  1. In Vitro Screening for Abiotic Stress Tolerance in Potent Biocontrol and Plant Growth Promoting Strains of Pseudomonas and Bacillus spp.

    Science.gov (United States)

    Praveen Kumar, G; Mir Hassan Ahmed, S K; Desai, Suseelendra; Leo Daniel Amalraj, E; Rasul, Abdul

    2014-01-01

    Plant growth promoting rhizobacteria (PGPR) has been identified as a group of microbes that are used for plant growth enhancement and biocontrol for management of plant diseases. The inconsistency in performance of these bacteria from laboratory to field conditions is compounded due to the prevailing abiotic stresses in the field. Therefore, selection of bacterial strains with tolerance to abiotic stresses would benefit the end-user by successful establishment of the strain for showing desired effects. In this study we attempted to isolate and identify strains of Bacillus and Pseudomonas spp. with stress tolerance and proven ability to inhibit the growth of potential phytopathogenic fungi. Screening of bacterial strains for high temperature (50°C), salinity (7% NaCl), and drought (-1.2 MPa) showed that stress tolerance was pronounced less in Pseudomonas isolates than in Bacillus strains. The reason behind this could be the formation of endospores by Bacillus isolates. Tolerance to drought was high in Pseudomonas strains than the other two stresses. Three strains, P8, P20 and P21 showed both salinity and temperature tolerance. P59 strain possessed promising antagonistic activity and drought tolerance. The magnitude of antagonism shown by Bacillus isolates was also higher when compared to Pseudomonas strains. To conclude, identification of microbial candidate strains with stress tolerance and other added characteristic features would help the end-user obtain the desired beneficial effects.

  2. Metabolite profiling reveals abiotic stress tolerance in Tn5 mutant of Pseudomonas putida.

    Directory of Open Access Journals (Sweden)

    Vasvi Chaudhry

    Full Text Available Pseudomonas is an efficient plant growth-promoting rhizobacteria (PGPR; however, intolerance to drought and high temperature limit its application in agriculture as a bioinoculant. Transposon 5 (Tn5 mutagenesis was used to generate a stress tolerant mutant from a PGPR Pseudomonas putida NBRI1108 isolated from chickpea rhizosphere. A mutant NBRI1108T, selected after screening of nearly 10,000 transconjugants, exhibited significant tolerance towards high temperature and drought. Southern hybridization analysis of EcoRI and XhoI restricted genomic DNA of NBRI1108T confirmed that it had a single Tn5 insertion. The metabolic changes in the polar and non-polar extracts of NBRI1108 and NBRI1108T were examined using 1H, 31P nuclear magnetic resonance (NMR spectroscopy and gas chromatography-mass spectrometry (GC-MS. Thirty six chemically diverse metabolites consisting of amino acids, fatty acids and phospholipids were identified and quantified. Insertion of Tn5 influenced amino acid and phospholipid metabolism and resulted in significantly higher concentration of aspartic acid, glutamic acid, glycinebetaine, glycerophosphatidylcholine (GPC and putrescine in NBRI1108T as compared to that in NBRI1108. The concentration of glutamic acid, glycinebetaine and GPC increased by 34%, 95% and 100%, respectively in the NBRI1108T as compared to that in NBRI1108. High concentration of glycerophosphatidylethanolamine (GPE and undetected GPC in NBRI1108 indicates that biosynthesis of GPE may have taken place via the methylation pathway of phospholipid biosynthesis. However, high GPC and low GPE concentration in NBRI1108T suggest that methylation pathway and phosphatidylcholine synthase (PCS pathway of phospholipid biosynthesis are being followed in the NBRI1108T. Application of multivariate principal component analysis (PCA on the quantified metabolites revealed clear variations in NBRI1108 and NBRI1108T in polar and non-polar metabolites. Identification of abiotic

  3. Metabolite profiling reveals abiotic stress tolerance in Tn5 mutant of Pseudomonas putida.

    Science.gov (United States)

    Chaudhry, Vasvi; Bhatia, Anil; Bharti, Santosh Kumar; Mishra, Shashank Kumar; Chauhan, Puneet Singh; Mishra, Aradhana; Sidhu, Om Prakash; Nautiyal, Chandra Shekhar

    2015-01-01

    Pseudomonas is an efficient plant growth-promoting rhizobacteria (PGPR); however, intolerance to drought and high temperature limit its application in agriculture as a bioinoculant. Transposon 5 (Tn5) mutagenesis was used to generate a stress tolerant mutant from a PGPR Pseudomonas putida NBRI1108 isolated from chickpea rhizosphere. A mutant NBRI1108T, selected after screening of nearly 10,000 transconjugants, exhibited significant tolerance towards high temperature and drought. Southern hybridization analysis of EcoRI and XhoI restricted genomic DNA of NBRI1108T confirmed that it had a single Tn5 insertion. The metabolic changes in the polar and non-polar extracts of NBRI1108 and NBRI1108T were examined using 1H, 31P nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-mass spectrometry (GC-MS). Thirty six chemically diverse metabolites consisting of amino acids, fatty acids and phospholipids were identified and quantified. Insertion of Tn5 influenced amino acid and phospholipid metabolism and resulted in significantly higher concentration of aspartic acid, glutamic acid, glycinebetaine, glycerophosphatidylcholine (GPC) and putrescine in NBRI1108T as compared to that in NBRI1108. The concentration of glutamic acid, glycinebetaine and GPC increased by 34%, 95% and 100%, respectively in the NBRI1108T as compared to that in NBRI1108. High concentration of glycerophosphatidylethanolamine (GPE) and undetected GPC in NBRI1108 indicates that biosynthesis of GPE may have taken place via the methylation pathway of phospholipid biosynthesis. However, high GPC and low GPE concentration in NBRI1108T suggest that methylation pathway and phosphatidylcholine synthase (PCS) pathway of phospholipid biosynthesis are being followed in the NBRI1108T. Application of multivariate principal component analysis (PCA) on the quantified metabolites revealed clear variations in NBRI1108 and NBRI1108T in polar and non-polar metabolites. Identification of abiotic stress

  4. Exogenous application of hydrogen sulfide donor sodium hydrosulfide enhanced multiple abiotic stress tolerance in bermudagrass (Cynodon dactylon (L). Pers.).

    Science.gov (United States)

    Shi, Haitao; Ye, Tiantian; Chan, Zhulong

    2013-10-01

    As a gaseous molecule, hydrogen sulfide (H2S) has been recently found to be involved in plant responses to multiple abiotic stress. In this study, salt (150 and 300 mM NaCl), osmotic (15% and 30% PEG6000) and cold (4 °C) stress treatments induced accumulation of endogenous H2S level, indicating that H2S might play a role in bermudagrass responses to salt, osmotic and cold stresses. Exogenous application of H2S donor (sodium hydrosulfide, NaHS) conferred improved salt, osmotic and freezing stress tolerances in bermudagrass, which were evidenced by decreased electrolyte leakage and increased survival rate under stress conditions. Additionally, NaHS treatment alleviated the reactive oxygen species (ROS) burst and cell damage induced by abiotic stress, via modulating metabolisms of several antioxidant enzymes [catalase (CAT), peroxidase (POD) and GR (glutathione reductase)] and non-enzymatic glutathione antioxidant pool and redox state. Moreover, exogenous NaHS treatment led to accumulation of osmolytes (proline, sucrose and soluble total sugars) in stressed bermudagrass plants. Taken together, all these data indicated the protective roles of H2S in bermudagrass responses to salt, osmotic and freezing stresses, via activation of the antioxidant response and osmolyte accumulation. These findings might be applicable to grass and crop engineering to improve abiotic stress tolerance.

  5. Multiple abiotic stress tolerance of the transformants yeast cells and the transgenic Arabidopsis plants expressing a novel durum wheat catalase.

    Science.gov (United States)

    Feki, Kaouthar; Kamoun, Yosra; Ben Mahmoud, Rihem; Farhat-Khemakhem, Ameny; Gargouri, Ali; Brini, Faiçal

    2015-12-01

    Catalases are reactive oxygen species scavenging enzymes involved in response to abiotic and biotic stresses. In this study, we described the isolation and functional characterization of a novel catalase from durum wheat, designed TdCAT1. Molecular Phylogeny analyses showed that wheat TdCAT1 exhibited high amino acids sequence identity to other plant catalases. Sequence homology analysis showed that TdCAT1 protein contained the putative calmodulin binding domain and a putative conserved internal peroxisomal targeting signal PTS1 motif around its C-terminus. Predicted three-dimensional structural model revealed the presence of four putative distinct structural regions which are the N-terminal arm, the β-barrel, the wrapping and the α-helical domains. TdCAT1 protein had the heme pocket that was composed by five essential residues. TdCAT1 gene expression analysis showed that this gene was induced by various abiotic stresses in durum wheat. The expression of TdCAT1 in yeast cells and Arabidopsis plants conferred tolerance to several abiotic stresses. Compared with the non-transformed plants, the transgenic lines maintained their growth and accumulated more proline under stress treatments. Furthermore, the amount of H2O2 was lower in transgenic lines, which was due to the high CAT and POD activities. Taken together, these data provide the evidence for the involvement of durum wheat catalase TdCAT1 in tolerance to multiple abiotic stresses in crop plants.

  6. Genetics and regulation of combined abiotic and biotic stress tolerance in tomato

    NARCIS (Netherlands)

    Kissoudis, C.

    2016-01-01

    Projections on the impact of climate change on agricultural productivity foresee prolonged and/or increased stress intensities and enlargement of a significant number of pathogens habitats. This significantly raises the occurrence probability of (new) abiotic and biotic stress combinations. With str

  7. Roots Withstanding their Environment : Exploiting Root System Architecture Responses to Abiotic Stress to Improve Crop Tolerance

    NARCIS (Netherlands)

    Koevoets, Iko T; Venema, Jan Henk; Elzenga, J Theo M; Testerink, Christa

    2016-01-01

    To face future challenges in crop production dictated by global climate changes, breeders and plant researchers collaborate to develop productive crops that are able to withstand a wide range of biotic and abiotic stresses. However, crop selection is often focused on shoot performance alone, as obse

  8. A wheat salinity-induced WRKY transcription factor TaWRKY93 confers multiple abiotic stress tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Qin, Yuxiang; Tian, Yanchen; Liu, Xiuzhi

    2015-08-21

    Wheat is an important crop in the world. But most of the cultivars are salt sensitive, and often adversely affected by salt stress. WRKY transcription factors play a major role in plant responses to salt stress, but the effective salinity regulatory WRKYs identified in bread wheat are limited and the mechanism of salt stress tolerance is also not well explored. Here, we identified a salt (NaCl) induced class II WRKY transcription factor TaWRKY93. Its transcript level was strongly induced by salt (NaCl) and exogenous abscisic acid (ABA). Over-expression of TaWRKY93 in Arabidopsis thaliana enhanced salt (NaCl), drought, low temperature and osmotic (mannitol) stress tolerance, mainly demonstrated by transgenic plants forming longer primary roots or more lateral roots on MS plates supplemented with NaCl and mannitol individually, higher survival rate under drought and low temperature stress. Further, transgenic plants maintained a more proline content, higher relative water content and less electrolyte leakage than the wild type plants. The transcript abundance of a series of abiotic stress-related genes was up-regulated in the TaWRKY93 transgenic plants. In summary, TaWRKY93 is a new positive regulator of abiotic stress, it may increase salinity, drought and low temperature stress tolerance through enhancing osmotic adjustment, maintaining membrane stability and increasing transcription of stress related genes, and contribute to the superior agricultural traits of SR3 through promoting root development. It can be used as a candidate gene for wheat transgenic engineering breeding against abiotic stress.

  9. Learning from Evolution: Thellungiella Generates New Knowledge on Essential and Critical Components of Abiotic Stress Tolerance in Plants

    Institute of Scientific and Technical Information of China (English)

    Anna Amtmann

    2009-01-01

    Thellungiella salsuginea (halophila) is a close relative of Arabidopsis thaliana but, unlike A. thaliana, it grows well in extreme conditions of cold, salt, and drought as well as nitrogen limitation. Over the last decade, many laboratories have started to use Thellungiella to investigate the physiological, metabolic, and molecular mechanisms of abiotic stress tolerance in plants, and new knowledge has been gained in particular with respect to ion transport and gene expression.The advantage of Thellungiella over other extremophile model plants is that it can be directly compared with Arabidopsis,and therefore generate information on both essential and critical components of stress tolerance. Thellungiella research is supported by a growing body of technical resources comprising physiological and molecular protocols, ecotype collections,expressed sequence tags, cDNA-libraries, microarrays, and a pending genome sequence. This review summarizes the current state of knowledge on Thellungiella and re-evaluates its usefulness as a model for research into plant stress tolerance.

  10. Abscisic Acid Signaling and Abiotic Stress Tolerance in Plants: A Review on Current Knowledge and Future Prospects

    Science.gov (United States)

    Vishwakarma, Kanchan; Upadhyay, Neha; Kumar, Nitin; Yadav, Gaurav; Singh, Jaspreet; Mishra, Rohit K.; Kumar, Vivek; Verma, Rishi; Upadhyay, R. G.; Pandey, Mayank; Sharma, Shivesh

    2017-01-01

    Abiotic stress is one of the severe stresses of environment that lowers the growth and yield of any crop even on irrigated land throughout the world. A major phytohormone abscisic acid (ABA) plays an essential part in acting toward varied range of stresses like heavy metal stress, drought, thermal or heat stress, high level of salinity, low temperature, and radiation stress. Its role is also elaborated in various developmental processes including seed germination, seed dormancy, and closure of stomata. ABA acts by modifying the expression level of gene and subsequent analysis of cis- and trans-acting regulatory elements of responsive promoters. It also interacts with the signaling molecules of processes involved in stress response and development of seeds. On the whole, the stress to a plant can be susceptible or tolerant by taking into account the coordinated activities of various stress-responsive genes. Numbers of transcription factor are involved in regulating the expression of ABA responsive genes by acting together with their respective cis-acting elements. Hence, for improvement in stress-tolerance capacity of plants, it is necessary to understand the mechanism behind it. On this ground, this article enlightens the importance and role of ABA signaling with regard to various stresses as well as regulation of ABA biosynthetic pathway along with the transcription factors for stress tolerance. PMID:28265276

  11. Over-expression of the apple spermidine synthase gene in pear confers multiple abiotic stress tolerance by altering polyamine titers.

    Science.gov (United States)

    Wen, Xiao-Peng; Pang, Xiao-Ming; Matsuda, Narumi; Kita, Masayuki; Inoue, Hiromichi; Hao, Yu-Jin; Honda, Chikako; Moriguchi, Takaya

    2008-04-01

    An apple spermidine synthase (SPDS) gene (MdSPDS1) was verified to encode a functional protein by the complementation of the spe3 yeast mutant, which lacks the SPDS gene. To justify our hypothesis that apple SPDS is involved in abiotic stress responses and to obtain transgenic fruit trees tolerant to abiotic stresses as well, MdSPDS1-over-expressing transgenic European pear (Pyrus communis L. 'Ballad') plants were created by Agrobacterium-mediated transformation. A total of 21 transgenic lines showing various spermidine (Spd) titers and MdSPDS1 expression levels were obtained. Selected lines were exposed to salt (150 mM NaCl), osmosis (300 mM mannitol), and heavy metal (500 microM CuSO4) stresses for evaluating their stress tolerances. Transgenic line no. 32, which was revealed to have the highest Spd accumulation and expression level of MdSPDS1, showed the strongest tolerance to these stresses. When growth increments, electrolyte leakage (EL), and values of thiobarbituric acid reactive substances (TBARS) were monitored, line no. 32 showed the lowest growth inhibition and the least increase in EL or TBARS under stress conditions. Spd titers in wild-type and transgenic lines showed diverse changes upon stresses, and these changes were not consistent with the changes in MdSPDS1 expressions. Moreover, there were no differences in the sodium concentration in the shoots between the wild type and line no. 32, whereas the copper concentration was higher in the wild type than in line no. 32. Although the mechanism(s) underlying the involvement of polyamines in stress responses is not known, these results suggest that the over-expression of the SPDS gene substantially increased the tolerance to multiple stresses by altering the polyamine titers in pear. Thus, MdSPDS1-over-expressing transgenic pear plants could be used to improve desert land and/or to repair polluted environments.

  12. Overexpressing Arabidopsis ABF3 increases tolerance to multiple abiotic stresses and reduces leaf size in alfalfa.

    Science.gov (United States)

    Wang, Zhi; Su, Guoxia; Li, Min; Ke, Qingbo; Kim, Soo Young; Li, Hongbing; Huang, Jin; Xu, Bingcheng; Deng, Xi-Ping; Kwak, Sang-Soo

    2016-12-01

    Arabidopsis ABSCISIC ACID-RESPONSIVE ELEMENT-BINDING FACTOR 3 (ABF3), a bZIP transcription factor, plays an important role in regulating multiple stress responses in plants. Overexpressing AtABF3 increases tolerance to various stresses in several plant species. Alfalfa (Medicago sativa L.), one of the most important perennial forage crops worldwide, has high yields, high nutritional value, and good palatability and is widely distributed in irrigated and semi-arid regions throughout the world. However, drought and salt stress pose major constraints to alfalfa production. In this study, we developed transgenic alfalfa plants (cv. Xinjiang Daye) expressing AtABF3 under the control of the sweetpotato oxidative stress-inducible SWPA2 promoter (referred to as SAF plants) via Agrobacterium tumefaciens-mediated transformation. After drought stress treatment, we selected two transgenic lines with high expression of AtABF3, SAF5 and SAF6, for further characterization. Under normal conditions, SAF plants showed smaller leaf size compared to non-transgenic (NT) plants, while no other morphological changes were observed. Moreover, SAF plants exhibited enhanced drought stress tolerance and better growth under drought stress treatment, which was accompanied by a reduced transpiration rate and lower reactive oxygen species contents. In addition, SAF plants showed an increased tolerance to salt and oxidative stress. Therefore, these transgenic AtABF3 alfalfa plants might be useful for breeding forage crops with enhanced tolerance to environmental stress for use in sustainable agriculture on marginal lands.

  13. Barley Genes as Tools to Confer Abiotic Stress Tolerance in Crops.

    Science.gov (United States)

    Gürel, Filiz; Öztürk, Zahide N; Uçarlı, Cüneyt; Rosellini, Daniele

    2016-01-01

    Barley is one of the oldest cultivated crops in the world with a high adaptive capacity. The natural tolerance of barley to stress has led to increasing interest in identification of stress responsive genes through small/large-scale omics studies, comparative genomics, and overexpression of some of these genes by genetic transformation. Two major categories of proteins involved in stress tolerance are transcription factors (TFs) responsible from the re-programming of the metabolism in stress environment, and genes encoding Late Embryogenesis Abundant (LEA) proteins, antioxidant enzymes, osmolytes, and transporters. Constitutive overexpression of several barley TFs, such as C-repeat binding factors (HvCBF4), dehydration-responsive element-binding factors (HvDREB1), and WRKYs (HvWRKY38), in transgenic plants resulted in higher tolerance to drought and salinity, possibly by effectively altering the expression levels of stress tolerance genes due to their higher DNA binding affinity. Na(+)/H(+) antiporters, channel proteins, and lipid transporters can also be the strong candidates for engineering plants for tolerance to salinity and low temperatures.

  14. Barley genes as a tool to confer abiotic stress tolerance in crops

    Directory of Open Access Journals (Sweden)

    Filiz Gürel

    2016-08-01

    Full Text Available Barley is one of the oldest cultivated crops in the world with a high adaptive capacity. The natural tolerance of barley to stress has led to increasing interest in identification of stress responsive genes through small/large-scale omics studies, comparative genomics, and overexpression of some of these genes by genetic transformation. Two major categories of proteins involved in stress tolerance are transcription factors (TFs responsible from the re-programming of the metabolism in stress environment, and genes encoding Late Embryogenesis Abundant (LEA proteins, antioxidant enzymes, osmolytes and transporters. Constitutive overexpression of several barley TFs, such as C-repeat binding factors (HvCBF4, dehydration-responsive element-binding factors (HvDREB1 and WRKYs (HvWRKY38, in transgenic plants resulted in higher tolerance to drought and salinity, possibly by effectively altering the expression levels of stress tolerance genes due to their higher DNA binding affinity. Na+/H+ antiporters, channel proteins, and lipid transporters can also be the strong candidates for engineering plants for tolerance to salinity and low temperatures.

  15. Expression Profiling of Abiotic Stress-Inducible Genes in response to Multiple Stresses in Rice (Oryza sativa L. Varieties with Contrasting Level of Stress Tolerance

    Directory of Open Access Journals (Sweden)

    Supratim Basu

    2014-01-01

    Full Text Available The present study considered transcriptional profiles and protein expression analyses from shoot and/or root tissues under three abiotic stress conditions, namely, salinity, dehydration, and cold, as well as following exogenous abscisic acid treatment, at different time points of stress exposure in three indica rice varieties, IR-29 (salt sensitive, Pokkali, and Nonabokra (both salt tolerant. The candidate genes chosen for expression studies were HKT-1, SOS-3, NHX-1, SAPK5, SAPK7, NAC-1, Rab16A, OSBZ8, DREBP2, CRT/DREBP, WRKY24, and WRKY71, along with the candidate proteins OSBZ8, SAMDC, and GST. Gene expression profile revealed considerable differences between the salt-sensitive and salt-tolerant rice varieties, as the expression in the latter was higher even at the constitutive level, whereas it was inducible only by corresponding stress signals in IR-29. Whether in roots or shoots, the transcriptional responses to different stressors peaked following 24 h of stress/ABA exposure, and the transcript levels enhanced gradually with the period of exposure. The generality of stress responses at the transcriptional level was therefore time dependent. Heat map data also showed differential transcript abundance in the three varieties, correlating the observation with transcript profiling. In silico analysis of the upstream regions of all the genes represented the existence of conserved sequence motifs in single or multiple copies that are indispensable to abiotic stress response. Overall, the transcriptome and proteome analysis undertaken in the present study indicated that genes/proteins conferring tolerance, belonging to different functional classes, were overrepresented, thus providing novel insight into the functional basis of multiple stress tolerance in indica rice varieties. The present work will pave the way in future to select gene(s for overexpression, so as to generate broad spectrum resistance to multiple stresses simultaneously.

  16. A thaumatin-like protein of Ocimum basilicum confers tolerance to fungal pathogen and abiotic stress in transgenic Arabidopsis.

    Science.gov (United States)

    Misra, Rajesh Chandra; Sandeep; Kamthan, Mohan; Kumar, Santosh; Ghosh, Sumit

    2016-05-06

    Plant often responds to fungal pathogens by expressing a group of proteins known as pathogenesis-related proteins (PRs). The expression of PR is mediated through pathogen-induced signal-transduction pathways that are fine-tuned by phytohormones such as methyl jasmonate (MeJA). Here, we report functional characterization of an Ocimum basilicum PR5 family member (ObTLP1) that was identified from a MeJA-responsive expression sequence tag collection. ObTLP1 encodes a 226 amino acid polypeptide that showed sequence and structural similarities with a sweet-tasting protein thaumatin of Thaumatococcus danielli and also with a stress-responsive protein osmotin of Nicotiana tabacum. The expression of ObTLP1 in O. basilicum was found to be organ-preferential under unstressed condition, and responsive to biotic and abiotic stresses, and multiple phytohormone elicitations. Bacterially-expressed recombinant ObTLP1 inhibited mycelial growth of the phytopathogenic fungi, Scleretonia sclerotiorum and Botrytis cinerea; thereby, suggesting its antifungal activity. Ectopic expression of ObTLP1 in Arabidopsis led to enhanced tolerance to S. sclerotiorum and B. cinerea infections, and also to dehydration and salt stress. Moreover, induced expression of the defense marker genes suggested up-regulation of the defense-response pathways in ObTLP1-expressing Arabidopsis upon fungal challenge. Thus, ObTLP1 might be useful for providing tolerance to the fungal pathogens and abiotic stresses in crops.

  17. ABI-like transcription factor gene TaABL1 from wheat improves multiple abiotic stress tolerances in transgenic plants.

    Science.gov (United States)

    Xu, Dong-Bei; Gao, Shi-Qing; Ma, You-Zhi; Xu, Zhao-Shi; Zhao, Chang-Ping; Tang, Yi-Miao; Li, Xue-Yin; Li, Lian-Cheng; Chen, Yao-Feng; Chen, Ming

    2014-12-01

    The phytohormone abscisic acid (ABA) plays crucial roles in adaptive responses of plants to abiotic stresses. ABA-responsive element binding proteins (AREBs) are basic leucine zipper transcription factors that regulate the expression of downstream genes containing ABA-responsive elements (ABREs) in promoter regions. A novel ABI-like (ABA-insensitive) transcription factor gene, named TaABL1, containing a conserved basic leucine zipper (bZIP) domain was cloned from wheat. Southern blotting showed that three copies were present in the wheat genome. Phylogenetic analyses indicated that TaABL1 belonged to the AREB subfamily of the bZIP transcription factor family and was most closely related to ZmABI5 in maize and OsAREB2 in rice. Expression of TaABL1 was highly induced in wheat roots, stems, and leaves by ABA, drought, high salt, and low temperature stresses. TaABL1 was localized inside the nuclei of transformed wheat mesophyll protoplast. Overexpression of TaABL1 enhanced responses of transgenic plants to ABA and hastened stomatal closure under stress, thereby improving tolerance to multiple abiotic stresses. Furthermore, overexpression of TaABL1 upregulated or downregulated the expression of some stress-related genes controlling stomatal closure in transgenic plants under ABA and drought stress conditions, suggesting that TaABL1 might be a valuable genetic resource for transgenic molecular breeding.

  18. A single gene all3940 (Dps) overexpression in Anabaena sp. PCC 7120 confers multiple abiotic stress tolerance via proteomic alterations.

    Science.gov (United States)

    Narayan, Om Prakash; Kumari, Nidhi; Bhargava, Poonam; Rajaram, Hema; Rai, Lal Chand

    2016-01-01

    DNA-binding proteins (Dps) induced during starvation play an important role in gene regulation and maintaining homeostasis in bacteria. The nitrogen-fixing cyanobacterium, Anabaena PCC7120, has four genes annotated as coding for Dps; however, the information on their physiological roles is limiting. One of the genes coding for Dps, 'all3940' was found to be induced under different abiotic stresses in Anabaena and upon overexpression enhanced the tolerance of Anabaena to a multitude of stresses, which included salinity, heat, heavy metals, pesticide, and nutrient starvation. On the other hand, mutation in the gene resulted in decreased growth of Anabaena. The modulation in the levels of All3940 in Anabaena, achieved either by overexpression of the protein or mutation of the gene, resulted in changes in the proteome, which correlated well with the physiological changes observed. Proteins required for varied physiological activities, such as photosynthesis, carbon-metabolism, oxidative stress alleviation, exhibited change in protein profile upon modulation of All3940 levels in Anabaena. This suggested a direct or an indirect effect of All3940 on the expression of the above stress-responsive proteins, thereby enhancing tolerance in Anabaena PCC7120. Thus, All3940, though categorized as a Dps, is possibly a general stress protein having a global role in regulating tolerance to multitude of stresses in Anabaena.

  19. OsPOP5, A Prolyl Oligopeptidase Family Gene from Rice Confers Abiotic Stress Tolerance in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Ping-Rong Wang

    2013-10-01

    Full Text Available The prolyl oligopeptidase family, which is a group of serine peptidases, can hydrolyze peptides smaller than 30 residues. The prolyl oligopeptidase family in plants includes four members, which are prolyl oligopeptidase (POP, EC3.4.21.26, dipeptidyl peptidase IV (DPPIV, EC3.4.14.5, oligopeptidase B (OPB, EC3.4.21.83, and acylaminoacyl peptidase (ACPH, EC3.4.19.1. POP is found in human and rat, and plays important roles in multiple biological processes, such as protein secretion, maturation and degradation of peptide hormones, and neuropathies, signal transduction and memory and learning. However, the function of POP is unclear in plants. In order to study POP function in plants, we cloned the cDNA of the OsPOP5 gene from rice by nested-PCR. Sequence analysis showed that the cDNA encodes a protein of 596 amino acid residues with Mw ≈ 67.29 kD. In order to analyze the protein function under different abiotic stresses, OsPOP5 was expressed in Escherichia coli. OsPOP5 protein enhanced the tolerance of E. coli to high salinity, high temperature and simulated drought. The results indicate that OsPOP5 is a stress-related gene in rice and it may play an important role in plant tolerance to abiotic stress.

  20. A wheat WRKY transcription factor TaWRKY10 confers tolerance to multiple abiotic stresses in transgenic tobacco.

    Directory of Open Access Journals (Sweden)

    Chen Wang

    Full Text Available WRKY transcription factors are reported to be involved in defense regulation, stress response and plant growth and development. However, the precise role of WRKY transcription factors in abiotic stress tolerance is not completely understood, especially in crops. In this study, we identified and cloned 10 WRKY genes from genome of wheat (Triticum aestivum L.. TaWRKY10, a gene induced by multiple stresses, was selected for further investigation. TaWRKY10 was upregulated by treatment with polyethylene glycol, NaCl, cold and H2O2. Result of Southern blot indicates that the wheat genome contains three copies of TaWRKY10. The TaWRKY10 protein is localized in the nucleus and functions as a transcriptional activator. Overexpression of TaWRKY10 in tobacco (Nicotiana tabacum L. resulted in enhanced drought and salt stress tolerance, mainly demonstrated by the transgenic plants exhibiting of increased germination rate, root length, survival rate, and relative water content under these stress conditions. Further investigation showed that transgenic plants also retained higher proline and soluble sugar contents, and lower reactive oxygen species and malonaldehyde contents. Moreover, overexpression of the TaWRKY10 regulated the expression of a series of stress related genes. Taken together, our results indicate that TaWRKY10 functions as a positive factor under drought and salt stresses by regulating the osmotic balance, ROS scavenging and transcription of stress related genes.

  1. Multiple abiotic stress tolerance in Vigna mungo is altered by overexpression of ALDRXV4 gene via reactive carbonyl detoxification.

    Science.gov (United States)

    Singh, Preeti; Kumar, Deepak; Sarin, Neera Bhalla

    2016-06-01

    Vigna mungo (blackgram) is an important leguminous pulse crop, which is grown for its protein rich edible seeds. Drought and salinity are the major abiotic stresses which adversely affect the growth and productivity of crop plants including blackgram. The ALDRXV4 belongs to the aldo-keto reductase superfamily of enzymes that catalyze the reduction of carbonyl metabolites in the cells and plays an important role in the osmoprotection and detoxification of the reactive carbonyl species. In the present study, we developed transgenic plants of V. mungo using Agrobacterium mediated transformation. The transgene integration was confirmed by Southern blot analysis whereas the expression was confirmed by RT-PCR, Western blot and enzyme activity. The T1 generation transgenic plants displayed improved tolerance to various environmental stresses, including drought, salt, methyl viologen and H2O2 induced oxidative stress. The increased aldose reductase activity, higher sorbitol content and less accumulation of the toxic metabolite, methylglyoxal in the transgenic lines under non-stress and stress (drought and salinity) conditions resulted in increased protection through maintenance of better photosynthetic efficiency, higher relative water content and less photooxidative damage. The accumulation of reactive oxygen species was remarkably decreased in the transgenic lines as compared with the wild type plants. This study of engineering multiple stress tolerance in blackgram, is the first report to date and this strategy for trait improvement is proposed to provide a novel germplasm for blackgram production on marginal lands.

  2. Proteome Analysis for Understanding Abiotic Stress (Salinity and Drought Tolerance in Date Palm (Phoenix dactylifera L.

    Directory of Open Access Journals (Sweden)

    Haddad A. El Rabey

    2015-01-01

    Full Text Available This study was carried out to study the proteome of date palm under salinity and drought stress conditions to possibly identify proteins involved in stress tolerance. For this purpose, three-month-old seedlings of date palm cultivar “Sagie” were subjected to drought (27.5 g/L polyethylene glycol 6000 and salinity stress conditions (16 g/L NaCl for one month. DIGE analysis of protein extracts identified 47 differentially expressed proteins in leaves of salt- and drought-treated palm seedlings. Mass spectrometric analysis identified 12 proteins; three out of them were significantly changed under both salt and drought stress, while the other nine were significantly changed only in salt-stressed plants. The levels of ATP synthase alpha and beta subunits, an unknown protein and some of RubisCO fragments were significantly changed under both salt and drought stress conditions. Changes in abundance of superoxide dismutase, chlorophyll A-B binding protein, light-harvesting complex1 protein Lhca1, RubisCO activase, phosphoglycerate kinase, chloroplast light-harvesting chlorophyll a/b-binding protein, phosphoribulokinase, transketolase, RubisCO, and some of RubisCO fragments were significant only for salt stress.

  3. An ATL78-like RING-H2 finger protein confers abiotic stress tolerance through interacting with RAV2 and CSN5B in tomato

    Directory of Open Access Journals (Sweden)

    Jianwen Song

    2016-08-01

    Full Text Available RING finger proteins play an important role in plant adaptation to abiotic stresses. In the present study, a wild tomato (Solanum habrochaites cold-induced RING-H2 finger gene, ShATL78L, was isolated, which has been identified as an abiotic stress responsive gene in tomato. The results showed that ShATL78L was constitutively expressed in various tissues such as root, lea petiole, stem, flower, and fruit. Cold stress up-regulated ShATL78L in the cold-tolerant S. habrochaites compared to the susceptible cultivated tomato (S. lycopersicum. Furthermore, ShATL78L expression was also regulated under different stresses such as drought, salt, heat, wound, osmotic stress, and exogenous hormones. Functional characterization showed that cultivated tomato overexpressing ShATL78L had improved tolerance to cold, drought and oxidative stresses compared to the wild-type and the knockdown lines. To understand the underlying molecular mechanism of ShATL78L regulating abiotic stress responses, we performed yeast one-hybrid and two-hybrid assays and found that RAV2 could bind to the promoter of ShATL78L and activate its transcription, and CSN5B could interact with ShATL78L to regulate abiotic stress responses. Taken together, these results show that ShATL78L plays an important role in regulating plant adaptation to abiotic stresses through bound by RAV2 and interacting with CSN5B.

  4. Grapevine NAC1 transcription factor as a convergent node in developmental processes, abiotic stresses, and necrotrophic/biotrophic pathogen tolerance.

    Science.gov (United States)

    Le Hénanff, Gaëlle; Profizi, Camille; Courteaux, Barbara; Rabenoelina, Fanja; Gérard, Clémentine; Clément, Christophe; Baillieul, Fabienne; Cordelier, Sylvain; Dhondt-Cordelier, Sandrine

    2013-11-01

    Transcription factors of the NAC family are known to be involved in various developmental processes and in response to environmental stresses. Whereas NAC genes have been widely studied in response to abiotic stresses, little is known about their role in response to biotic stresses, especially in crops. Here, the first characterization of a Vitis vinifera L. NAC member, named VvNAC1, and involved in organ development and defence towards pathogens is reported. Expression profile analysis of VvNAC1 showed that its expression is closely associated with later stages of leaf, flower, and berry development, suggesting a role in plant senescence. Moreover, VvNAC1 expression is stimulated in Botrytis cinerea- or microbe-associated molecular pattern (MAMP)-infected berries or leaves. Furthermore, cold, wounding, and defence-related hormones such as salicylic acid, methyl jasmonate, ethylene, and abscisic acid are all able to induce VvNAC1 expression in grapevine leaves. VvNAC1-overexpressing Arabidopsis plants exhibit enhanced tolerance to osmotic, salt, and cold stresses and to B. cinerea and Hyaloperonospora arabidopsidis pathogens. These plants present a modified pattern of defence gene markers (AtPR-1, AtPDF1.2, and AtVSP1) after stress application, suggesting that VvNAC1 is an important regulatory component of the plant signalling defence cascade. Collectively, these results provide evidence that VvNAC1 could represent a node of convergence regulating grapevine development and stress responses, including defence against necrotrophic and biotrophic pathogens.

  5. Melatonin enhances plant growth and abiotic stress tolerance in soybean plants.

    Science.gov (United States)

    Wei, Wei; Li, Qing-Tian; Chu, Ya-Nan; Reiter, Russel J; Yu, Xiao-Min; Zhu, Dan-Hua; Zhang, Wan-Ke; Ma, Biao; Lin, Qing; Zhang, Jin-Song; Chen, Shou-Yi

    2015-02-01

    Melatonin is a well-known agent that plays multiple roles in animals. Its possible function in plants is less clear. In the present study, we tested the effect of melatonin (N-acetyl-5-methoxytryptamine) on soybean growth and development. Coating seeds with melatonin significantly promoted soybean growth as judged from leaf size and plant height. This enhancement was also observed in soybean production and their fatty acid content. Melatonin increased pod number and seed number, but not 100-seed weight. Melatonin also improved soybean tolerance to salt and drought stresses. Transcriptome analysis revealed that salt stress inhibited expressions of genes related to binding, oxidoreductase activity/process, and secondary metabolic processes. Melatonin up-regulated expressions of the genes inhibited by salt stress, and hence alleviated the inhibitory effects of salt stress on gene expressions. Further detailed analysis of the affected pathways documents that melatonin probably achieved its promotional roles in soybean through enhancement of genes involved in cell division, photosynthesis, carbohydrate metabolism, fatty acid biosynthesis, and ascorbate metabolism. Our results demonstrate that melatonin has significant potential for improvement of soybean growth and seed production. Further study should uncover more about the molecular mechanisms of melatonin's function in soybeans and other crops.

  6. Introduction of Pea DNA Helicase 45 Into Sugarcane (Saccharum spp. Hybrid) Enhances Cell Membrane Thermostability And Upregulation Of Stress-responsive Genes Leads To Abiotic Stress Tolerance.

    Science.gov (United States)

    Augustine, Sruthy Maria; Ashwin Narayan, J; Syamaladevi, Divya P; Appunu, C; Chakravarthi, M; Ravichandran, V; Tuteja, Narendra; Subramonian, N

    2015-05-01

    DNA helicases are motor proteins that play an essential role in nucleic acid metabolism, by providing a duplex-unwinding function. To improve the drought and salinity tolerance of sugarcane, a DEAD-box helicase gene isolated from pea with a constitutive promoter, Port Ubi 2.3 was transformed into the commercial sugarcane variety Co 86032 through Agrobacterium-mediated transformation, and the transgenics were screened for tolerance to soil moisture stress and salinity. The transgene integration was confirmed through polymerase chain reaction, and the V 0 transgenic events showed significantly higher cell membrane thermostability under normal irrigated conditions. The V 1 transgenic events were screened for tolerance to soil moisture stress and exhibited significantly higher cell membrane thermostability, transgene expression, relative water content, gas exchange parameters, chlorophyll content, and photosynthetic efficiency under soil moisture stress compared to wild-type (WT). The overexpression of PDH45 transgenic sugarcane also led to the upregulation of DREB2-induced downstream stress-related genes. The transgenic events demonstrated higher germination ability and better chlorophyll retention than WT under salinity stress. Our results suggest the possibility for development of increased abiotic stress tolerant sugarcane cultivars through overexpression of PDH45 gene. Perhaps this is the first report, which provides evidence for increased drought and salinity tolerance in sugarcane through overexpression of PDH45.

  7. Functional and transcriptome analysis reveals an acclimatization strategy for abiotic stress tolerance mediated by Arabidopsis NF-YA family members.

    Science.gov (United States)

    Leyva-González, Marco Antonio; Ibarra-Laclette, Enrique; Cruz-Ramírez, Alfredo; Herrera-Estrella, Luis

    2012-01-01

    Nuclear Factor Y (NF-Y) is a heterotrimeric complex formed by NF-YA/NF-YB/NF-YC subunits that binds to the CCAAT-box in eukaryotic promoters. In contrast to other organisms, in which a single gene encodes each subunit, in plants gene families of over 10 members encode each of the subunits. Here we report that five members of the Arabidopsis thaliana NF-YA family are strongly induced by several stress conditions via transcriptional and miR169-related post-transcriptional mechanisms. Overexpression of NF-YA2, 7 and 10 resulted in dwarf late-senescent plants with enhanced tolerance to several types of abiotic stress. These phenotypes are related to alterations in sucrose/starch balance and cell elongation observed in NF-YA overexpressing plants. The use of transcriptomic analysis of transgenic plants that express miR169-resistant versions of NF-YA2, 3, 7, and 10 under an estradiol inducible system, as well as a dominant-repressor version of NF-YA2 revealed a set of genes, whose promoters are enriched in NF-Y binding sites (CCAAT-box) and that may be directly regulated by the NF-Y complex. This analysis also suggests that NF-YAs could participate in modulating gene regulation through positive and negative mechanisms. We propose a model in which the increase in NF-YA transcript levels in response to abiotic stress is part of an adaptive response to adverse environmental conditions in which a reduction in plant growth rate plays a key role.

  8. In planta transformation of sorghum (Sorghum bicolor (L.) Moench) using TPS1 gene for enhancing tolerance to abiotic stresses

    Indian Academy of Sciences (India)

    Varalaxmi Yellisetty; L. A. Reddy; Maheswari Mandapaka

    2015-09-01

    An in planta transformation protocol for sorghum (Sorghum bicolor (L.) Moench) using shoot apical meristem of germinating seedlings is reported in this study. Agrobacterium tumefaciens strain, LBA4404 with pCAMBIA1303 vector and construct pCAMBIA1303TPS1 were individually used for transformation. Since, the transgene is integrated into the cells of already differentiated tissues, the T0 plants were chimeric and stable integration was observed in T1 generation. -Glucuronidase (GUS) expression in the seedlings and spikelets of emerging cob was the first indication of transformability in T0 generation which was further confirmed by PCR analysis using hpt and TPS1 gene-specific primers. Screening on 25 mg/L hygromycin combined with PCR analysis was used for selection of transformants in the T1 generation. Transformation efficiencies ranged between 34–38% and 26–34% using pCAMBIA1303 vector and construct pCAMBIA1303TPS1, respectively. Molecular characterization of the T2 transgenics using PCR, RT-PCR and Southern blot analyses further revealed the integration, expression and inheritance of the transgene. These results indicate the feasibility of the method to generate transgenics with pCAM-BIA1303 vector and construct pCAMBIA1303TPS1. The abiotic stress tolerance of TPS1 transgenics developed in the present study was evident by the ability of the transformants to tolerate 200 mM NaCl as well as higher root growth and biomass.

  9. A novel Glycine soja tonoplast intrinsic protein gene responds to abiotic stress and depresses salt and dehydration tolerance in transgenic Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Xi; Li, Yong; Ji, Wei; Bai, Xi; Cai, Hua; Zhu, Dan; Sun, Xiao-Li; Chen, Lian-Jiang; Zhu, Yan-Ming

    2011-07-15

    Tonoplast intrinsic protein (TIP) is a subfamily of the aquaporin (AQP), also known as major intrinsic protein (MIP) family, and regulates water movement across vacuolar membranes. Some reports have implied that TIP genes are associated with plant tolerance to some abiotic stresses that cause water loss, such as drought and high salinity. In our previous work, we found that an expressed sequence tag (EST) representing a TIP gene in our Glycine soja EST library was inducible by abiotic stresses. This TIP was subsequently isolated from G. soja with cDNA library screening, EST assembly and PCR, and named as GsTIP2;1. The expression patterns of GsTIP2;1 in G. soja under low temperature, salt and dehydration stress were different in leaves and roots. Though GsTIP2;1 is a stress-induced gene, overexpression of GsTIP2;1 in Arabidopsis thaliana depressed tolerance to salt and dehydration stress, but did not affect seedling growth under cold or favorable conditions. Higher dehydration speed was detected in Arabidopsis plants overexpressing GsTIP2;1, implying GsTIP2;1 might mediate stress sensitivity by enhancing water loss in the plant. Such a result is not identical to previous reports, providing some new information about the relationship between TIP and plant abiotic stress tolerance.

  10. Overexpression of small heat shock protein LimHSP16.45 in Arabidopsis enhances tolerance to abiotic stresses.

    Directory of Open Access Journals (Sweden)

    Changjun Mu

    Full Text Available Small heat shock proteins (smHSPs play important and extensive roles in plant defenses against abiotic stresses. We cloned a gene for a smHSP from the David Lily (Lilium davidii (E. H. Wilson Raffill var. Willmottiae, which we named LimHSP16.45 based on its protein molecular weight. Its expression was induced by many kinds of abiotic stresses in both the lily and transgenic plants of Arabidopsis. Heterologous expression enhanced cell viability of the latter under high temperatures, high salt, and oxidative stress, and heat shock granules (HSGs formed under heat or salinity treatment. Assays of enzymes showed that LimHSP16.45 overexpression was related to greater activity by superoxide dismutase and catalase in transgenic lines. Therefore, we conclude that heterologous expression can protect plants against abiotic stresses by preventing irreversible protein aggregation, and by scavenging cellular reactive oxygen species.

  11. The transcription factor SlAREB1 confers drought, salt stress tolerance and regulates biotic and abiotic stress-related genes in tomato.

    Science.gov (United States)

    Orellana, Sandra; Yañez, Mónica; Espinoza, Analía; Verdugo, Isabel; González, Enrique; Ruiz-Lara, Simón; Casaretto, José A

    2010-12-01

    Members of the abscisic acid-responsive element binding protein (AREB)/abscisic acid-responsive element binding factor (ABF) subfamily of basic leucine zipper (bZIP) transcription factors have been implicated in abscisic acid (ABA) and abiotic stress responses in plants. Here we describe two members identified in cultivated tomato (Solanum lycopersicum), named SlAREB1 and SlAREB2. Expression of SlAREB1 and SlAREB2 is induced by drought and salinity in both leaves and root tissues, although that of SlAREB1 was more affected. In stress assays, SlAREB1-overexpressing transgenic tomato plants showed increased tolerance to salt and water stress compared to wild-type and SlAREB1-down-regulating transgenic plants, as assessed by physiological parameters such as relative water content (RWC), chlorophyll fluorescence and damage by lipoperoxidation. In order to identify SlAREB1 target genes responsible for the enhanced tolerance, microarray and cDNA-amplified fragment length polymorphism (AFLP) analyses were performed. Genes encoding oxidative stress-related proteins, lipid transfer proteins (LTPs), transcription regulators and late embryogenesis abundant proteins were found among the up-regulated genes in SlAREB1-overexpressing lines, especially in aerial tissue. Notably, several genes encoding defence proteins associated with responses to biotic stress (e.g. pathogenesis-related proteins, protease inhibitors, and catabolic enzymes) were also up-regulated by SlAREB1 overexpression, suggesting that this bZIP transcription factor is involved in ABA signals that participate in abiotic stress and possibly in response to pathogens.

  12. PL1 fusion gene: a novel visual selectable marker gene that confers tolerance to multiple abiotic stresses in transgenic tomato.

    Science.gov (United States)

    Jin, Feng; Li, Shu; Dang, Lijie; Chai, Wenting; Li, Pengli; Wang, Ning Ning

    2012-10-01

    Visual selectable markers, including the purple color caused by the accumulation of anthocyanins, have been proposed for use as antibiotic-free alternatives. However, the excessive accumulation of anthocyanins seriously inhibits the growth and development of transgenic plants. In our study, the AtDWF4 promoter from Arabidopsis and the tomato LeANT1 gene, encoding a MYB transcription factor, were used to construct the PL1 fusion gene to test whether it could be used as a visual selectable marker gene for tomato transformation. All the PL1 transgenic shoots exhibited intense purple color on shoot induction medium. In the transgenic tomato plants, PL1 was highly expressed in the cotyledons, but expressed only slightly in the true leaves and other organs. The expression of PL1 had no significantly adverse effects on the growth or development of the transgenic tomato plants, and conferred tolerance to multiple abiotic stresses in them. With the “cut off green shoots” method, multiple independent 35S::GFP transgenic tomato lines were successfully obtained using PL1 as the selectable marker gene. These results suggest that PL1 has potential application of visual selectable marker gene for tomato transformation.

  13. Anastatica hierochuntica, an Arabidopsis Desert Relative, Is Tolerant to Multiple Abiotic Stresses and Exhibits Species-Specific and Common Stress Tolerance Strategies with Its Halophytic Relative, Eutrema (Thellungiella) salsugineum

    Science.gov (United States)

    Eshel, Gil; Shaked, Ruth; Kazachkova, Yana; Khan, Asif; Eppel, Amir; Cisneros, Aroldo; Acuna, Tania; Gutterman, Yitzhak; Tel-Zur, Noemi; Rachmilevitch, Shimon; Fait, Aaron; Barak, Simon

    2017-01-01

    The search for novel stress tolerance determinants has led to increasing interest in plants native to extreme environments – so called “extremophytes.” One successful strategy has been comparative studies between Arabidopsis thaliana and extremophyte Brassicaceae relatives such as the halophyte Eutrema salsugineum located in areas including cold, salty coastal regions of China. Here, we investigate stress tolerance in the desert species, Anastatica hierochuntica (True Rose of Jericho), a member of the poorly investigated lineage III Brassicaceae. We show that A. hierochuntica has a genome approximately 4.5-fold larger than Arabidopsis, divided into 22 diploid chromosomes, and demonstrate that A. hierochuntica exhibits tolerance to heat, low N and salt stresses that are characteristic of its habitat. Taking salt tolerance as a case study, we show that A. hierochuntica shares common salt tolerance mechanisms with E. salsugineum such as tight control of shoot Na+ accumulation and resilient photochemistry features. Furthermore, metabolic profiling of E. salsugineum and A. hierochuntica shoots demonstrates that the extremophytes exhibit both species-specific and common metabolic strategies to cope with salt stress including constitutive up-regulation (under control and salt stress conditions) of ascorbate and dehydroascorbate, two metabolites involved in ROS scavenging. Accordingly, A. hierochuntica displays tolerance to methyl viologen-induced oxidative stress suggesting that a highly active antioxidant system is essential to cope with multiple abiotic stresses. We suggest that A. hierochuntica presents an excellent extremophyte Arabidopsis relative model system for understanding plant survival in harsh desert conditions. PMID:28144244

  14. The NAC-type transcription factor OsNAC2 regulates ABA-dependent genes and abiotic stress tolerance in rice

    Science.gov (United States)

    Shen, Jiabin; Lv, Bo; Luo, Liqiong; He, Jianmei; Mao, Chanjuan; Xi, Dandan; Ming, Feng

    2017-01-01

    Plants can perceive environmental changes and respond to external stressors. Here, we show that OsNAC2, a member of the NAC transcription factor family, was strongly induced by ABA and osmotic stressors such as drought and high salt. With reduced yields under drought conditions at the flowering stage, OsNAC2 overexpression lines had lower resistance to high salt and drought conditions. RNAi plants showed enhanced tolerance to high salinity and drought stress at both the vegetative and flowering stages. Furthermore, RNAi plants had improved yields after drought stress. A microarray assay indicated that many ABA-dependent stress-related genes were down-regulated in OsNAC2 overexpression lines. We further confirmed that OsNAC2 directly binds the promoters of LATE EMBRYOGENESIS ABUNDANT 3 (OsLEA3) and Stress-Activated Protein Kinases 1 (OsSAPK1), two marker genes in the abiotic stress and ABA response pathways, respectively. Our results suggest that in rice OsNAC2 regulates both abiotic stress responses and ABA-mediated responses, and acts at the junction between the ABA and abiotic stress pathways. PMID:28074873

  15. Abiotic stressors and stress responses

    DEFF Research Database (Denmark)

    Sulmon, Cecile; Van Baaren, Joan; Cabello-Hurtado, Francisco

    2015-01-01

    Abstract Organisms are regularly subjected to abiotic stressors related to increasing anthropogenic activities, including chemicals and climatic changes that induce major stresses. Based on various key taxa involved in ecosystem functioning (photosynthetic microorganisms, plants, invertebrates), ...

  16. Molecular cloning and functional characterization of a novel apple MdCIPK6L gene reveals its involvement in multiple abiotic stress tolerance in transgenic plants.

    Science.gov (United States)

    Wang, Rong-Kai; Li, Ling-Li; Cao, Zhong-Hui; Zhao, Qiang; Li, Ming; Zhang, Ling-Yun; Hao, Yu-Jin

    2012-05-01

    CBL-interacting protein kinases (CIPKs) are involved in many aspects of plant responses to abiotic stresses. However, their functions are poorly understood in fruit trees. In this study, a salt-induced MdCIPK6L gene was isolated from apple. Its expression was positively induced by abiotic stresses, stress-related hormones and exogenous Ca(2+). MdCIPK6L was not homologous to AtSOS2, however, its ectopic expression functionally complemented Arabidopsis sos2 mutant. Furthermore, yeast two-hybrid assay showed that MdCIPK6L protein interacted with AtSOS3, indicating that it functions in salt tolerance partially like AtSOS2 through SOS pathway. As a result, the overexpression of both MdCIPK6L and MdCIPK6LT175D remarkably enhanced the tolerance to salt, osmotic/drought and chilling stresses, but did not affect root growth, in transgenic Arabidopsis and apple. Also, T-to-D mutation to MdCIPK6L at Thr175 did not affect its function. These differences between MdCIPK6L and other CIPKs, especially CIPK6s, indicate that MdCIPK6L encodes a novel CIPK in apple. Finally, MdCIPK6L overexpression also conferred tolerance to salt, drought and chilling stresses in transgenic tomatoes. Therefore, MdCIPK6L functions in stress tolerance crossing the species barriers, and is supposed to be a potential candidate gene to improve stress tolerance by genetic manipulation in apple and other crops.

  17. Chemical Priming of Plants Against Multiple Abiotic Stresses: Mission Possible?

    KAUST Repository

    Savvides, Andreas

    2015-12-15

    Crop plants are subjected to multiple abiotic stresses during their lifespan that greatly reduce productivity and threaten global food security. Recent research suggests that plants can be primed by chemical compounds to better tolerate different abiotic stresses. Chemical priming is a promising field in plant stress physiology and crop stress management. We review here promising chemical agents such as sodium nitroprusside, hydrogen peroxide, sodium hydrosulfide, melatonin, and polyamines that can potentially confer enhanced tolerance when plants are exposed to multiple abiotic stresses. The challenges and opportunities of chemical priming are addressed, with the aim to boost future research towards effective application in crop stress management.

  18. Chemical Priming of Plants Against Multiple Abiotic Stresses: Mission Possible?

    Science.gov (United States)

    Savvides, Andreas; Ali, Shawkat; Tester, Mark; Fotopoulos, Vasileios

    2016-04-01

    Crop plants are subjected to multiple abiotic stresses during their lifespan that greatly reduce productivity and threaten global food security. Recent research suggests that plants can be primed by chemical compounds to better tolerate different abiotic stresses. Chemical priming is a promising field in plant stress physiology and crop stress management. We review here promising chemical agents such as sodium nitroprusside, hydrogen peroxide, sodium hydrosulfide, melatonin, and polyamines that can potentially confer enhanced tolerance when plants are exposed to multiple abiotic stresses. The challenges and opportunities of chemical priming are addressed, with the aim to boost future research towards effective application in crop stress management.

  19. Arabidopsis Raf-Like Mitogen-Activated Protein Kinase Kinase Kinase Gene Raf43 Is Required for Tolerance to Multiple Abiotic Stresses.

    Directory of Open Access Journals (Sweden)

    Nasar Virk

    Full Text Available Mitogen-activated protein kinase (MAPK cascades are critical signaling modules that mediate the transduction of extracellular stimuli into intracellular response. A relatively large number of MAPKKKs have been identified in a variety of plant genomes but only a few of them have been studied for their biological function. In the present study, we identified an Arabidopsis Raf-like MAPKKK gene Raf43 and studied its function in biotic and abiotic stress response using a T-DNA insertion mutant raf43-1 and two Raf43-overexpressing lines Raf43-OE#1 and Raf43-OE#13. Expression of Raf43 was induced by multiple abiotic and biotic stresses including treatments with drought, mannitol and oxidative stress or defense signaling molecule salicylic acid and infection with necrotrophic fungal pathogen Botrytis cinerea. Seed germination and seedling root growth of raf43-1 were significantly inhibited on MS medium containing mannitol, NaCl, H2O2 or methyl viologen (MV while seed germination and seedling root growth of the Raf43-OE#1 and Raf43-OE#13 lines was similar to wild type Col-0 under the above stress conditions. Soil-grown raf43-1 plants exhibited reduced tolerance to MV, drought and salt stress. Abscisic acid inhibited significantly seed germination and seedling root growth of the raf43-1 line but had no effect on the two Raf43-overexpressing lines. Expression of stress-responsive RD17 and DREB2A genes was significantly down-regulated in raf43-1 plants. However, the raf43-1 and Raf43-overexpressing plants showed similar disease phenotype to the wild type plants after infection with B. cinerea or Pseudomonas syringae pv. tomato DC3000. Our results demonstrate that Raf43, encoding for a Raf-like MAPKKK, is required for tolerance to multiple abiotic stresses in Arabidopsis.

  20. OsLEA3-2, an abiotic stress induced gene of rice plays a key role in salt and drought tolerance.

    Directory of Open Access Journals (Sweden)

    Jianli Duan

    Full Text Available Late embryogenesis abundant (LEA proteins are involved in tolerance to drought, cold and high salinity in many different organisms. In this report, a LEA protein producing full-length gene OsLEA3-2 was identified in rice (Oryza sativa using the Rapid Amplification of cDNA Ends (RACE method. OsLEA3-2 was found to be only expressed in the embryo and can be induced by abiotic stresses. The coding protein localizes to the nucleus and overexpression of OsLEA3-2 in yeast improved growth performance compared with control under salt- and osmotic-stress conditions. OsLEA3-2 was also inserted into pHB vector and overexpressed in Arabidopsis and rice. The transgenic Arabidopsis seedlings showed better growth on MS media supplemented with 150 mM mannitol or 100 mM NaCl as compared with wild type plants. The transgenic rice also showed significantly stronger growth performance than control under salinity or osmotic stress conditions and were able to recover after 20 days of drought stress. In vitro analysis showed that OsLEA3-2 was able to protect LDH from aggregation on freezing and inactivation on desiccation. These results indicated that OsLEA3-2 plays an important role in tolerance to abiotic stresses.

  1. Seed priming with BABA (β-amino butyric acid): a cost-effective method of abiotic stress tolerance in Vigna radiata (L.) Wilczek.

    Science.gov (United States)

    Jisha, K C; Puthur, Jos T

    2016-03-01

    The effects of β-amino butyric acid (BABA) on abiotic stress tolerance potential of three Vigna radiata varieties were studied. The reduction in the growth of seedlings subjected to NaCl/polyethylene glycol (PEG) stress is alleviated by BABA seed priming, which also enhanced photosynthetic pigment content and photosynthetic and mitochondrial activities, and also modified the chlorophyll a fluorescence-related parameters. Moreover, BABA seed priming reduced malondialdehyde content in the seedlings and enhanced the accumulation of proline, total protein, total carbohydrate, nitrate reductase activity, and activities of antioxidant enzymes like guaiacol peroxidase and superoxide dismutase. Most of these positive features of BABA priming were predominantly exhibited when the plants were encountered with stress (NaCl/PEG). The BABA content in the BABA-treated green gram seeds and seedlings was also detected and quantified with high-performance thin layer chromatography (HPTLC), and it revealed that the priming effect of BABA initiated in seeds and further gets carried over to the seedlings. It was concluded that BABA seed priming improved the drought and salinity stress tolerance potential of all the three green gram varieties, and it was evident in the NaCl-tolerant variety Pusa Vishal as compared to Pusa Ratna (abiotic stress sensitive) and Pusa 9531(drought tolerant). Dual mode in cost effectiveness of BABA priming is evident from: (1) the positive features of priming are being exhibited more during the exposure of plants to stress, and (2) priming of seedlings can be carried out by BABA application to seeds at very low concentration and volume.

  2. A Cyclin Dependent Kinase Regulatory Subunit (CKS) Gene of Pigeonpea Imparts Abiotic Stress Tolerance and Regulates Plant Growth and Development in Arabidopsis.

    Science.gov (United States)

    Tamirisa, Srinath; Vudem, Dashavantha R; Khareedu, Venkateswara R

    2017-01-01

    Frequent climatic changes in conjunction with other extreme environmental factors are known to affect growth, development and productivity of diverse crop plants. Pigeonpea, a major grain legume of the semiarid tropics, endowed with an excellent deep-root system, is known as one of the important drought tolerant crop plants. Cyclin dependent kinases (CDKs) are core cell cycle regulators and play important role in different aspects of plant growth and development. The cyclin-dependent kinase regulatory subunit gene (CKS) was isolated from the cDNA library of pigeonpea plants subjected to drought stress. Pigeonpea CKS (CcCKS) gene expression was detected in both the root and leaf tissues of pigeonpea and was upregulated by polyethylene glycol (PEG), mannitol, NaCl and abscisic acid (ABA) treatments. The overexpression of CcCKS gene in Arabidopsis significantly enhanced tolerance of transgenics to drought and salt stresses as evidenced by different physiological parameters. Under stress conditions, transgenics showed higher biomass, decreased rate of water loss, decreased MDA levels, higher free proline contents, and glutathione levels. Moreover, under stress conditions transgenics exhibited lower stomatal conductance, lower transpiration, and higher photosynthetic rates. However, under normal conditions, CcCKS-transgenics displayed decreased plant growth rate, increased cell size and decreased stomatal number compared to those of wild-type plants. Real-time polymerase chain reaction revealed that CcCKS could regulate the expression of both ABA-dependent and ABA-independent genes associated with abiotic stress tolerance as well as plant growth and development. As such, the CcCKS seems promising and might serve as a potential candidate gene for enhancing the abiotic stress tolerance of crop plants.

  3. Overproduction of the membrane-bound receptor-like protein kinase 1, RPK1, enhances abiotic stress tolerance in Arabidopsis.

    Science.gov (United States)

    Osakabe, Yuriko; Mizuno, Shinji; Tanaka, Hidenori; Maruyama, Kyonoshin; Osakabe, Keishi; Todaka, Daisuke; Fujita, Yasunari; Kobayashi, Masatomo; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2010-03-19

    RPK1 (receptor-like protein kinase 1) localizes to the plasma membrane and functions as a regulator of abscisic acid (ABA) signaling in Arabidopsis. In our current study, we investigated the effect of RPK1 disruption and overproduction upon plant responses to drought stress. Transgenic Arabidopsis overexpressing the RPK1 protein showed increased ABA sensitivity in their root growth and stomatal closure and also displayed less transpirational water loss. In contrast, a mutant lacking RPK1 function, rpk1-1, was found to be resistant to ABA during these processes and showed increased water loss. RPK1 overproduction in these transgenic plants thus increased their tolerance to drought stress. We performed microarray analysis of RPK1 transgenic plants and observed enhanced expression of several stress-responsive genes, such as Cor15a, Cor15b, and rd29A, in addition to H(2)O(2)-responsive genes. Consistently, the expression levels of ABA/stress-responsive genes in rpk1-1 had decreased compared with wild type. The results suggest that the overproduction of RPK1 enhances both the ABA and drought stress signaling pathways. Furthermore, the leaves of the rpk1-1 plants exhibit higher sensitivity to oxidative stress upon ABA-pretreatment, whereas transgenic plants overproducing RPK1 manifest increased tolerance to this stress. Our current data suggest therefore that RPK1 overproduction controls reactive oxygen species homeostasis and enhances both water and oxidative stress tolerance in Arabidopsis.

  4. Overexpression of carnation S-adenosylmethionine decarboxylase gene generates a broad-spectrum tolerance to abiotic stresses in transgenic tobacco plants.

    Science.gov (United States)

    Wi, Soo Jin; Kim, Woo Taek; Park, Ky Young

    2006-10-01

    Polyamines (PAs), such as putrescine, spermidine, and spermine, are present in all living organism and implicate in a wide range of cellular physiological processes. We have used transgenic technology in an attempt to evaluate their potential for mitigating the adverse effects of several abiotic stresses in plants. Sense construct of full-length cDNA for S-adenosylmethionine decarboxylase (SAMDC), a key enzyme in PA biosynthesis, from carnation (Dianthus caryophyllus L.) flower was introduced into tobacco (Nicotiana tabacum L.) by Agrobacterium tumefaciens-mediated transformation. Several transgenic lines overexpressing SAMDC gene under the control of cauliflower mosaic virus 35S promoter accumulated soluble total PAs by 2.2 (S16-S-4) to 3.1 (S16-S-1) times than wild-type plants. The transgenic tobacco did not show any difference in organ phenotype compared to the wild-type. The number and weight of seeds increased, and net photosynthetic rate also increased in transgenic plants. Stress-induced damage was attenuated in these transgenic plants, in the symptom of visible yellowing and chlorophyll degradation after all experienced stresses such as salt stress, cold stress, acidic stress, and abscisic acid treatment. H2O2-induced damage was attenuated by spermidine treatment. Transcripts for antioxidant enzymes (ascorbate peroxidase, manganase superoxide dismutase, and glutathione S-transferase) in transgenic plants and GUS activity transformed with SAMDC promoter::GUS fusion were induced more significantly by stress treatment, compared to control. These results that the transgenic plants with sense SAMDC cDNA are more tolerant to abiotic stresses than wild-type plants suggest that PAs may play an important role in contributing stress tolerance in plants.

  5. TaSK5, an abiotic stress-inducible GSK3/shaggy-like kinase from wheat, confers salt and drought tolerance in transgenic Arabidopsis.

    Science.gov (United States)

    Christov, Nikolai Kirilov; Christova, Petya Koeva; Kato, Hideki; Liu, Yuelin; Sasaki, Kentaro; Imai, Ryozo

    2014-11-01

    A novel cold-inducible GSK3/shaggy-like kinase, TaSK5, was isolated from winter wheat using a macroarray-based differential screening approach. TaSK5 showed high similarity to Arabidopsis subgroup I GSK3/shaggy-like kinases ASK-alpha, AtSK-gamma and ASK-epsilon. RNA gel blot analyses revealed TaSK5 induction by cold and NaCl treatments and to a lesser extent by drought treatment. TaSK5 functionally complemented the cold- and salt-sensitive phenotypes of a yeast GSK3/shaggy-like kinase mutant, △mck1. Transgenic Arabidopsis plants overexpressing TaSK5 cDNA showed enhanced tolerance to salt and drought stresses. By contrast, the tolerance of the transgenic plants to freezing stress was not altered. Microarray analysis revealed that a number of abiotic stress-inducible genes were constitutively induced in the transgenic Arabidopsis plants, suggesting that TaSK5 may function in a novel signal transduction pathway that appears to be unrelated to DREB1/CBF regulon and may involve crosstalk between abiotic and hormonal signals.

  6. BnSIP1-1, a Trihelix Family Gene, Mediates Abiotic Stress Tolerance and ABA Signaling in Brassica napus

    Science.gov (United States)

    Luo, Junling; Tang, Shaohua; Mei, Fengling; Peng, Xiaojue; Li, Jun; Li, Xiaofei; Yan, Xiaohong; Zeng, Xinhua; Liu, Fang; Wu, Yuhua; Wu, Gang

    2017-01-01

    The trihelix family genes have important functions in light-relevant and other developmental processes, but their roles in response to adverse environment are largely unclear. In this study, we identified a new gene, BnSIP1-1, which fell in the SIP1 (6b INTERACTING PROTEIN1) clade of the trihelix family with two trihelix DNA binding domains and a fourth amphipathic α-helix. BnSIP1-1 protein specifically targeted to the nucleus, and its expression can be induced by abscisic acid (ABA) and different stresses. Overexpression of BnSIP1-1 improved seed germination under osmotic pressure, salt, and ABA treatments. Moreover, BnSIP1-1 decreased the susceptibility of transgenic seedlings to osmotic pressure and ABA treatments, whereas there was no difference under salt stress between the transgenic and wild-type seedlings. ABA level in the transgenic seedlings leaves was higher than those in the control plants under normal condition. Under exogenous ABA treatment and mannitol stress, the accumulation of ABA in the transgenic plants was higher than that in the control plants; while under salt stress, the difference of ABA content before treatment was gradually smaller with the prolongation of salt treatment time, then after 24 h of treatment the ABA level was similar in transgenic and wild-type plants. The transcription levels of several general stress marker genes (BnRD29A, BnERD15, and BnLEA1) were higher in the transgenic plants than the wild-type plants, whereas salt-responsive genes (BnSOS1, BnNHX1, and BnHKT) were not significantly different or even reduced compared with the wild-type plants, which indicated that BnSIP1-1 specifically exerted different regulatory mechanisms on the osmotic- and salt-response pathways in seedling period. Overall, these findings suggested that BnSIP1-1 played roles in ABA synthesis and signaling, salt and osmotic stress response. To date, information about the involvement of the Brassica napus trihelix gene in abiotic response is scarce

  7. Environmental Association Analyses Identify Candidates for Abiotic Stress Tolerance in Glycine soja, the Wild Progenitor of Cultivated Soybeans.

    Science.gov (United States)

    Anderson, Justin E; Kono, Thomas J Y; Stupar, Robert M; Kantar, Michael B; Morrell, Peter L

    2016-04-07

    Natural populations across a species range demonstrate population structure owing to neutral processes such as localized origins of mutations and migration limitations. Selection also acts on a subset of loci, contributing to local adaptation. An understanding of the genetic basis of adaptation to local environmental conditions is a fundamental goal in basic biological research. When applied to crop wild relatives, this same research provides the opportunity to identify adaptive genetic variation that may be used to breed for crops better adapted to novel or changing environments. The present study explores an ex situ conservation collection, the USDA germplasm collection, genotyped at 32,416 SNPs to identify population structure and test for associations with bioclimatic and biophysical variables in Glycine soja, the wild progenitor of Glycine max (soybean). Candidate loci were detected that putatively contribute to adaptation to abiotic stresses. The identification of potentially adaptive variants in this ex situ collection may permit a more targeted use of germplasm collections.

  8. Specific roles of tocopherols and tocotrienols in seed longevity and germination tolerance to abiotic stress in transgenic rice.

    Science.gov (United States)

    Chen, Defu; Li, Yanlan; Fang, Tao; Shi, Xiaoli; Chen, Xiwen

    2016-03-01

    Tocopherols and tocotrienols are lipophilic antioxidants that are abundant in plant seeds. Although their roles have been extensively studied, our understanding of their functions in rice seeds is still limited. In this study, on the basis of available RNAi rice plants constitutively silenced for homogentisate phytyltransferase (HPT) and tocopherol cyclase (TC), we developed transgenic plants that silenced homogentisate geranylgeranyl transferase (HGGT). All the RNAi plants showed significantly reduced germination percentages and a higher proportion of abnormal seedlings than the control plants, with HGGT transgenics showing the most severe phenotype. The accelerated aging phenotype corresponded well with the amount of H2O2 accumulated in the embryo, glucose level, and ion leakage, but not with the amount of O(2-) accumulated in the embryo and lipid hydroperoxides levels in these genotypes. Under abiotic stress conditions, HPT and TC transgenics showed lower germination percentage and seedling growth than HGGT transgenics, while HGGT transgenics showed almost the same status as the wild type. Therefore, we proposed that tocopherols in the germ may protect the embryo from reactive oxygen species under both accelerated aging and stress conditions, whereas tocotrienols in the pericarp may exclusively help in reducing the metabolic activity of the seed during accelerated aging.

  9. Research Progress in Tomato Responses to Abiotic Stress

    Institute of Scientific and Technical Information of China (English)

    Jianing XU; Gang LIU; Liyun ZHANG

    2016-01-01

    Tomato is a kind of vegetable with high economic benefits in protected farmland.Accounting for 30% of vegetable planting area in the entire protected farmland,tomato plays an essential role in cultivation of protected vegetable.Different abiotic stresses have different degrees of influence on growth and development,yield,and fruit quality of tomatoes.Therefore,finding out life activity rules of tomatoes under different abiotic stresses will be of great significance to breeding for stress tolerance and increasing tomato yield and income.This paper made an overview of research progress in tomato responses to abiotic stress in growth and development,physiology and biochemistry,and gene regulation.

  10. Recent Molecular Advances on Downstream Plant Responses to Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Cláudia Regina Batista de Souza

    2012-07-01

    Full Text Available Abiotic stresses such as extremes of temperature and pH, high salinity and drought, comprise some of the major factors causing extensive losses to crop production worldwide. Understanding how plants respond and adapt at cellular and molecular levels to continuous environmental changes is a pre-requisite for the generation of resistant or tolerant plants to abiotic stresses. In this review we aimed to present the recent advances on mechanisms of downstream plant responses to abiotic stresses and the use of stress-related genes in the development of genetically engineered crops.

  11. Overexpression of soybean ubiquitin-conjugating enzyme gene GmUBC2 confers enhanced drought and salt tolerance through modulating abiotic stress-responsive gene expression in Arabidopsis.

    Science.gov (United States)

    Zhou, Guo-An; Chang, Ru-Zhen; Qiu, Li-Juan

    2010-03-01

    Previous studies have shown that ubiquitination plays important roles in plant abiotic stress responses. In the present study, the ubiquitin-conjugating enzyme gene GmUBC2, a homologue of yeast RAD6, was cloned from soybean and functionally characterized. GmUBC2 was expressed in all tissues in soybean and was up-regulated by drought and salt stress. Arabidopsis plants overexpressing GmUBC2 were more tolerant to salinity and drought stresses compared with the control plants. Through expression analyses of putative downstream genes in the transgenic plants, we found that the expression levels of two ion antiporter genes AtNHX1 and AtCLCa, a key gene involved in the biosynthesis of proline, AtP5CS, and the copper chaperone for superoxide dismutase gene AtCCS, were all increased significantly in the transgenic plants. These results suggest that GmUBC2 is involved in the regulation of ion homeostasis, osmolyte synthesis, and oxidative stress responses. Our results also suggest that modulation of the ubiquitination pathway could be an effective means of improving salt and drought tolerance in plants through genetic engineering.

  12. Mechanisms of nitric oxide crosstalk with reactive oxygen species scavenging enzymes during abiotic stress tolerance in plants.

    Science.gov (United States)

    Arora, Dhara; Jain, Prachi; Singh, Neha; Kaur, Harmeet; Bhatla, Satish C

    2016-01-01

    Nitric oxide (NO) acts in a concentration and redox-dependent manner to counteract oxidative stress either by directly acting as an antioxidant through scavenging reactive oxygen species (ROS), such as superoxide anions (O(2)(-)*), to form peroxynitrite (ONOO(-)) or by acting as a signaling molecule, thereby altering gene expression. NO can interact with different metal centres in proteins, such as heme-iron, zinc-sulfur clusters, iron-sulfur clusters, and copper, resulting in the formation of a stable metal-nitrosyl complex or production of varied biochemical signals, which ultimately leads to modification of protein structure/function. The thiols (ferrous iron-thiol complex and nitrosothiols) are also involved in the metabolism and mobilization of NO. Thiols bind to NO and transport it to the site of action whereas nitrosothiols release NO after intercellular diffusion and uptake into the target cells. S-nitrosoglutathione (GSNO) also has the ability to transnitrosylate proteins. It is an NO˙ reservoir and a long-distance signaling molecule. Tyrosine nitration of proteins has been suggested as a biomarker of nitrosative stress as it can lead to either activation or inhibition of target proteins. The exact molecular mechanism(s) by which exogenous and endogenously generated NO (or reactive nitrogen species) modulate the induction of various genes affecting redox homeostasis, are being extensively investigated currently by various research groups. Present review provides an in-depth analysis of the mechanisms by which NO interacts with and modulates the activity of various ROS scavenging enzymes, particularly accompanying ROS generation in plants in response to varied abiotic stress.

  13. A novel alkyl hydroperoxidase (AhpD) of Anabaena PCC7120 confers abiotic stress tolerance in Escherichia coli.

    Science.gov (United States)

    Shrivastava, Alok Kumar; Singh, Shilpi; Singh, Prashant Kumar; Pandey, Sarita; Rai, L C

    2015-01-01

    In silico analysis together with cloning, molecular characterization and heterologous expression reports that the hypothetical protein All5371 of Anabaena sp. PCC7120 is a novel hydroperoxide scavenging protein similar to AhpD of bacteria. The presence of E(X)11CX HC(X)3H motif in All5371 confers peroxidase activity and closeness to bacterial AhpD which is also reflected by its highest 3D structure homology with Rhodospirillum rubrum AhpD. Heterologous expression of all5371 complimented for ahpC and conferred resistance in MJF178 strain (ahpCF::Km) of Escherichia coli. All5371 reduced the organic peroxide more efficiently than inorganic peroxide and the recombinant E. coli strain following exposure to H2O2, CdCl2, CuCl2, heat, UV-B and carbofuron registered increased growth over wild-type and mutant E. coli transformed with empty vector. Appreciable expression of all5371 in Anabaena sp. PCC7120 as measured by qRT-PCR under selected stresses and their tolerance against H2O2, tBOOH, CuOOH and menadione attested its role in stress tolerance. In view of the above, All5371 of Anabaena PCC7120 emerged as a new hydroperoxide detoxifying protein.

  14. Arabidopsis thaliana Contains Both Ni2+ and Zn2+ Dependent Glyoxalase I Enzymes and Ectopic Expression of the Latter Contributes More towards Abiotic Stress Tolerance in E. coli

    Science.gov (United States)

    Jain, Muskan; Batth, Rituraj; Kumari, Sumita; Mustafiz, Ananda

    2016-01-01

    The glyoxalase pathway is ubiquitously found in all the organisms ranging from prokaryotes to eukaryotes. It acts as a major pathway for detoxification of methylglyoxal (MG), which deleteriously affects the biological system in stress conditions. The first important enzyme of this system is Glyoxalase I (GLYI). It is a metalloenzyme which requires divalent metal ions for its activity. This divalent metal ion can be either Zn2+ as found in most of eukaryotes or Ni2+ as seen in prokaryotes. In the present study, we have found three active GLYI enzymes (AtGLYI2, AtGLYI3 and AtGLYI6) belonging to different metal activation classes coexisting in Arabidopsis thaliana. These enzymes have been found to efficiently complement the GLYI yeast mutants. These three enzymes have been characterized in terms of their activity, metal dependency, kinetic parameters and their role in conferring tolerance to multiple abiotic stresses in E. coli and yeast. AtGLYI2 was found to be Zn2+ dependent whereas AtGLYI3 and AtGLYI6 were Ni2+ dependent. Enzyme activity of Zn2+ dependent enzyme, AtGLYI2, was observed to be exceptionally high (~250–670 fold) as compared to Ni2+ dependent enzymes, AtGLYI3 and AtGLYI6. The activity of these GLYI enzymes correlated well to their role in stress tolerance. Heterologous expression of these enzymes in E. coli led to better tolerance against various stress conditions. This is the first report of a higher eukaryotic species having multiple active GLYI enzymes belonging to different metal activation classes. PMID:27415831

  15. Arabidopsis thaliana Contains Both Ni2+ and Zn2+ Dependent Glyoxalase I Enzymes and Ectopic Expression of the Latter Contributes More towards Abiotic Stress Tolerance in E. coli.

    Directory of Open Access Journals (Sweden)

    Muskan Jain

    Full Text Available The glyoxalase pathway is ubiquitously found in all the organisms ranging from prokaryotes to eukaryotes. It acts as a major pathway for detoxification of methylglyoxal (MG, which deleteriously affects the biological system in stress conditions. The first important enzyme of this system is Glyoxalase I (GLYI. It is a metalloenzyme which requires divalent metal ions for its activity. This divalent metal ion can be either Zn2+ as found in most of eukaryotes or Ni2+ as seen in prokaryotes. In the present study, we have found three active GLYI enzymes (AtGLYI2, AtGLYI3 and AtGLYI6 belonging to different metal activation classes coexisting in Arabidopsis thaliana. These enzymes have been found to efficiently complement the GLYI yeast mutants. These three enzymes have been characterized in terms of their activity, metal dependency, kinetic parameters and their role in conferring tolerance to multiple abiotic stresses in E. coli and yeast. AtGLYI2 was found to be Zn2+ dependent whereas AtGLYI3 and AtGLYI6 were Ni2+ dependent. Enzyme activity of Zn2+ dependent enzyme, AtGLYI2, was observed to be exceptionally high (~250-670 fold as compared to Ni2+ dependent enzymes, AtGLYI3 and AtGLYI6. The activity of these GLYI enzymes correlated well to their role in stress tolerance. Heterologous expression of these enzymes in E. coli led to better tolerance against various stress conditions. This is the first report of a higher eukaryotic species having multiple active GLYI enzymes belonging to different metal activation classes.

  16. A cold-induced myo-inositol transporter-like gene confers tolerance to multiple abiotic stresses in transgenic tobacco plants.

    Science.gov (United States)

    Sambe, Mame Abdou Nahr; He, Xueying; Tu, Qinghua; Guo, Zhenfei

    2015-03-01

    A full length cDNA encoding a myo-inositol transporter-like protein, named as MfINT-like, was cloned from Medicago sativa subsp. falcata (herein falcata), a species with greater cold tolerance than alfalfa (M. sativa subsp. sativa). MfINT-like is located on plasma membranes. MfINT-like transcript was induced 2-4 h after exogenous myo-inositol treatment, 24-96 h with cold, and 96 h by salinity. Given that myo-inositol accumulates higher in falcata after 24 h of cold treatment, myo-inositol is proposed to be involved in cold-induced expression of MfINT-like. Higher levels of myo-inositol was observed in leaves of transgenic tobacco plants overexpressing MfINT-like than the wild-type but not in the roots of plants grown on myo-inositol containing medium, suggesting that transgenic plants had higher myo-inositol transport activity than the wild-type. Transgenic plants survived better to freezing temperature, and had lower ion leakage and higher maximal photochemical efficiency of photosystem II (Fv /Fm ) after chilling treatment. In addition, greater plant fresh weight was observed in transgenic plants as compared with the wild-type when plants were grown under drought or salinity stress. The results suggest that MfINT-like mediated transport of myo-inositol is associated with plant tolerance to abiotic stresses.

  17. Application of Selected Reaction Monitoring Mass Spectrometry to Field Grown Crop Plants To Allow Dissection of the Molecular Mechanisms of Abiotic Stress Tolerance.

    Directory of Open Access Journals (Sweden)

    Richard P. Jacoby

    2013-02-01

    Full Text Available One major constraint upon the application of molecular crop breeding approaches is the small number of genes linked to agronomically desirable traits through defined biochemical mechanisms. Proteomic investigations of crop plants under abiotic stress treatments have identified many proteins that differ in control versus stress comparisons, however this broad profiling of cell physiology is poorly suited to ranking the effects and identifying the specific proteins that are causative in agronomically relevant traits. Here we will reason that insights into a protein’s function, its biochemical process and links to stress tolerance are more likely to arise through approaches that evaluate these differential abundances of proteins and include varietal comparisons, precise discrimination of protein isoforms, enrichment of functionally related proteins and integration of proteomic datasets with physiological measurements of both lab and field grown plants. We will briefly explain how applying the emerging proteomic technology of multiplexed selective reaction monitoring mass spectrometry with its accuracy and throughput can facilitate and enhance these approaches and provide a clear means to rank the growing cohort of stress responsive proteins. We will also highlight the benefit of integrating proteomic analyses with cultivar-specific genetic databases and physiological assessments of cultivar performance in relevant field environments for revealing deeper insights into molecular crop improvement.

  18. Transgenic poplar expressing Arabidopsis YUCCA6 exhibits auxin-overproduction phenotypes and increased tolerance to abiotic stress.

    Science.gov (United States)

    Ke, Qingbo; Wang, Zhi; Ji, Chang Yoon; Jeong, Jae Cheol; Lee, Haeng-Soon; Li, Hongbing; Xu, Bingcheng; Deng, Xiping; Kwak, Sang-Soo

    2015-09-01

    YUCCA6, a member of the YUCCA family of flavin monooxygenase-like proteins, is involved in the tryptophan-dependent IAA biosynthesis pathway and responses to environmental cues in Arabidopsis. However, little is known about the role of the YUCCA pathway in auxin biosynthesis in poplar. Here, we generated transgenic poplar (Populus alba × P. glandulosa) expressing the Arabidopsis YUCCA6 gene under the control of the oxidative stress-inducible SWPA2 promoter (referred to as SY plants). Three SY lines (SY7, SY12 and SY20) were selected based on the levels of AtYUCCA6 transcript. SY plants displayed auxin-overproduction morphological phenotypes, such as rapid shoot growth and retarded main root development with increased root hair formation. In addition, SY plants had higher levels of free IAA and early auxin-response gene transcripts. SY plants exhibited tolerance to drought stress, which was associated with reduced levels of reactive oxygen species. Furthermore, SY plants showed delayed hormone- and dark-induced senescence in detached leaves due to higher photosystem II efficiency and less membrane permeability. These results suggest that the conserved IAA biosynthesis pathway mediated by YUCCA family members exists in poplar.

  19. Spermidine exodus and oxidation in the apoplast induced by abiotic stress is responsible for H2O2 signatures that direct tolerance responses in tobacco.

    Science.gov (United States)

    Moschou, Panagiotis N; Paschalidis, Konstantinos A; Delis, Ioannis D; Andriopoulou, Athina H; Lagiotis, George D; Yakoumakis, Dimitrios I; Roubelakis-Angelakis, Kalliopi A

    2008-06-01

    Polyamines (PAs) exert a protective effect against stress challenges, but their molecular role in this remains speculative. In order to detect the signaling role of apoplastic PA-derived hydrogen peroxide (H2O2) under abiotic stress, we developed a series of tobacco (Nicotiana tabacum cv Xanthi) transgenic plants overexpressing or downregulating apoplastic polyamine oxidase (PAO; S-pao and A-pao plants, respectively) or downregulating S-adenosyl-l-methionine decarboxylase (samdc plants). Upon salt stress, plants secreted spermidine (Spd) into the apoplast, where it was oxidized by the apoplastic PAO, generating H2O2. A-pao plants accumulated less H2O2 and exhibited less programmed cell death (PCD) than did wild-type plants, in contrast with S-pao and samdc downregulating plants. Induction of either stress-responsive genes or PCD was dependent on the level of Spd-derived apoplastic H2O2. Thus, in wild-type and A-pao plants, stress-responsive genes were efficiently induced, although in the latter at a lower rate, while S-pao plants, with higher H2O2 levels, failed to accumulate stress-responsive mRNAs, inducing PCD instead. Furthermore, decreasing intracellular PAs, while keeping normal apoplastic Spd oxidation, as in samdc downregulating transgenic plants, caused enhanced salinity-induced PCD. These results reveal that salinity induces the exodus of Spd into the apoplast, where it is catabolized by PAO, producing H2O2. The accumulated H2O2 results in the induction of either tolerance responses or PCD, depending also on the levels of intracellular PAs.

  20. Different peroxidase activities and expression of abiotic stress-related peroxidases in apical root segments of wheat genotypes with different drought stress tolerance under osmotic stress.

    Science.gov (United States)

    Csiszár, Jolán; Gallé, Agnes; Horváth, Edit; Dancsó, Piroska; Gombos, Magdolna; Váry, Zsolt; Erdei, László; Györgyey, János; Tari, Irma

    2012-03-01

    One-week-old seedlings of Triticum aestivum L. cv. Plainsman V, a drought tolerant; and Cappelle Desprez, a drought sensitive wheat cultivar were subjected gradually to osmotic stress using polyethylene glycol (PEG 6000) reaching 400 mOsm on the 11th day. Compared to controls cv. Plainsman V maintained the root growth and relative water content of root tissues, while these parameters were decreased in the drought sensitive cv. Cappelle Desprez under PEG-mediated osmotic stress. Simultaneously, H(2)O(2) content in 1-cm-long apical segment of roots comprising the proliferation and elongation zone, showed a transient increase in cv. Plainsman V and a permanent raise in cv. Cappelle Desprez. Measurements of the transcript levels of selected class III peroxidase (TaPrx) coding sequences revealed significant differences between the two cultivars on the 9th day, two days after applying 100 mOsm PEG. The abundance of TaPrx04 transcript was enhanced transitionally in the root apex of cv. Plainsman V but decreased in cv. Cappelle Desprez under osmotic stress while the expression of TaPrx01, TaPrx03, TaPrx19, TaPrx68, TaPrx107 and TaPrx109-C decreased to different extents in both cultivars. After a transient decrease, activities of soluble peroxidase fractions of crude protein extracts rose in both cultivars on day 11, but the activities of cell wall-bound fractions increased only in cv. Cappelle Desprez under osmotic stress. Parallel with high H(2)O(2) content of the tissues, certain isoenzymes of covalently bound fraction in cv. Cappelle Desprez showed increased activity suggesting that they may limit the extension of root cell walls in this cultivar.

  1. An S-domain receptor-like kinase, OsSIK2, confers abiotic stress tolerance and delays dark-induced leaf senescence in rice.

    Science.gov (United States)

    Chen, Li-Juan; Wuriyanghan, Hada; Zhang, Yu-Qin; Duan, Kai-Xuan; Chen, Hao-Wei; Li, Qing-Tian; Lu, Xiang; He, Si-Jie; Ma, Biao; Zhang, Wan-Ke; Lin, Qing; Chen, Shou-Yi; Zhang, Jin-Song

    2013-12-01

    Receptor-like kinases play important roles in plant development and defense responses; however, their functions in other processes remain unclear. Here, we report that OsSIK2, an S-domain receptor-like kinase from rice (Oryza sativa), is involved in abiotic stress and the senescence process. OsSIK2 is a plasma membrane-localized protein with kinase activity in the presence of Mn(2+). OsSIK2 is expressed mainly in rice leaf and sheath and can be induced by NaCl, drought, cold, dark, and abscisic acid treatment. Transgenic plants overexpressing OsSIK2 and mutant sik2 exhibit enhanced and reduced tolerance to salt and drought stress, respectively, compared with the controls. Interestingly, a truncated version of OsSIK2 without most of the extracellular region confers higher salt tolerance than the full-length OsSIK2, likely through the activation of different sets of downstream genes. Moreover, seedlings of OsSIK2-overexpressing transgenic plants exhibit early leaf development and a delayed dark-induced senescence phenotype, while mutant sik2 shows the opposite phenotype. The downstream PR-related genes specifically up-regulated by full-length OsSIK2 or the DREB-like genes solely enhanced by truncated OsSIK2 are all induced by salt, drought, and dark treatments. These results indicate that OsSIK2 may integrate stress signals into a developmental program for better adaptive growth under unfavorable conditions. Manipulation of OsSIK2 should facilitate the improvement of production in rice and other crops.

  2. Polyamines and abiotic stress in plants: A complex relationship

    Directory of Open Access Journals (Sweden)

    Rakesh eMinocha

    2014-05-01

    Full Text Available The physiological relationship between abiotic stress in plants and polyamines was reported more than 40 years ago. Ever since there has been a debate as to whether increased polyamines protect plants against abiotic stress (e.g. due to their ability to deal with oxidative radicals or cause damage to them (perhaps due to hydrogen peroxide produced by their catabolism. The observation that cellular polyamines are typically elevated in plants under both short-term as well as long-term abiotic stress conditions is consistent with the possibility of their dual effects, i.e. being a protector as well as a perpetrator of stress damage to the cells. The observed increase in tolerance of plants to abiotic stress when their cellular contents are elevated by either exogenous treatment with polyamines or through genetic engineering with genes encoding polyamine biosynthetic enzymes is indicative of a protective role for them. However, through their catabolic production of hydrogen peroxide and acrolein, both strong oxidizers, they can potentially be the cause of cellular harm during stress. In fact, somewhat enigmatic but strong positive relationship between abiotic stress and foliar polyamines has been proposed as a potential biochemical marker of persistent environmental stress in forest trees in which phenotypic symptoms of stress are not yet visible. Such markers may help forewarn forest managers to undertake amelioration strategies before the appearance of visual symptoms of stress and damage at which stage it is often too late for implementing strategies for stress remediation and reversal of damage. This review provides a comprehensive and critical evaluation of the published literature on interactions between abiotic stress and polyamines in plants, and examines the experimental strategies used to understand the functional significance of this relationship with the aim of improving plant productivity, especially under conditions of abiotic stress.

  3. Simultaneous expression of abiotic stress responsive transcription factors, AtDREB2A, AtHB7 and AtABF3 improves salinity and drought tolerance in peanut (Arachis hypogaea L..

    Directory of Open Access Journals (Sweden)

    Vittal Pruthvi

    Full Text Available Drought, salinity and extreme temperatures are the most common abiotic stresses, adversely affecting plant growth and productivity. Exposure of plants to stress activates stress signalling pathways that induce biochemical and physiological changes essential for stress acclimation. Stress tolerance is governed by multiple traits, and importance of a few traits in imparting tolerance has been demonstrated. Under drought, traits linked to water mining and water conservation, water use efficiency and cellular tolerance (CT to desiccation are considered to be relevant. In this study, an attempt has been made to improve CT in drought hardy crop, peanut (Arachis hypogaea L., cv. TMV2 by co-expressing stress-responsive transcription factors (TFs, AtDREB2A, AtHB7 and AtABF3, associated with downstream gene expression. Transgenic plants simultaneously expressing these TFs showed increased tolerance to drought, salinity and oxidative stresses compared to wild type, with an increase in total plant biomass. The transgenic plants exhibited improved membrane and chlorophyll stability due to enhanced reactive oxygen species scavenging and osmotic adjustment by proline synthesis under stress. The improvement in stress tolerance in transgenic lines were associated with induced expression of various CT related genes like AhGlutaredoxin, AhAldehyde reductase, AhSerine threonine kinase like protein, AhRbx1, AhProline amino peptidase, AhHSP70, AhDIP and AhLea4. Taken together the results indicate that co-expression of stress responsive TFs can activate multiple CT pathways, and this strategy can be employed to improve abiotic stress tolerance in crop plants.

  4. The persimmon 9-lipoxygenase gene DkLOX3 plays positive roles in both promoting senescence and enhancing tolerance to abiotic stress

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    Yali eHou

    2015-12-01

    Full Text Available The lipoxygenase (LOX pathway is a key regulator for lipid peroxidation, which is crucial for plant senescence and defence pathways. In this study, the transcriptional expression patterns of three persimmon (Diospyros kaki L. ‘Fupingjianshi’ 9-lipoxygenase genes (DkLOX1, DkLOX3 and DkLOX4 were investigated. DkLOX1 was specifically expressed in fruit, particularly in young fruit, and showed little response to the postharvest environments. DkLOX4 was expressed in all tissues and slightly stimulated by mechanical damage and low temperature. DkLOX3 was expressed mainly in mature fruit, and the expression was extremely high throughout the storage period, apparently up-regulated by mechanical damage and high carbon dioxide treatments. Further functional analysis showed that overexpression of DkLOX3 in tomato (Solanum lycopersicum cv. Micro-Tom accelerated fruit ripening and softening. This was accompanied by higher MDA content and lycopene accumulation, advanced ethylene release peak and elevated expression of ethylene synthesis genes, including ACS2, ACO1 and ACO3. In addition, DkLOX3 overexpression promoted dark induced transgenic Arabidopsis leaf senescence with more chlorophyll loss, increased electrolyte leakage and MDA content. Furthermore, the functions of DkLOX3 in response to abiotic stresses, including osmotic stress, high salinity and drought were investigated. Arabidopsis DkLOX3-OX transgenic lines were found to be more tolerant to osmotic stress with higher germination rate and root growth than wild-type. Moreover, DkLOX3-OX Arabidopsis plants also exhibited enhanced resistance to high salinity and drought, with similar decreased O2- and H2O2 accumulation and upregulation of stress-responsive genes expression, including RD22, RD29A, RD29B and NCED3, except for FRY1, which plays a negative role in stress response. Overall, these results suggested that DkLOX3 plays positive roles both in promoting ripening and senescence through lipid

  5. The Persimmon 9-lipoxygenase Gene DkLOX3 Plays Positive Roles in Both Promoting Senescence and Enhancing Tolerance to Abiotic Stress.

    Science.gov (United States)

    Hou, Yali; Meng, Kun; Han, Ye; Ban, Qiuyan; Wang, Biao; Suo, Jiangtao; Lv, Jingyi; Rao, Jingping

    2015-01-01

    The lipoxygenase (LOX) pathway is a key regulator for lipid peroxidation, which is crucial for plant senescence and defense pathways. In this study, the transcriptional expression patterns of three persimmon (Diospyros kaki L. 'Fupingjianshi') 9-lipoxygenase genes (DkLOX1, DkLOX3, and DkLOX4) were investigated. DkLOX1 was specifically expressed in fruit, particularly in young fruit, and showed little response to the postharvest environments. DkLOX4 was expressed in all tissues and slightly stimulated by mechanical damage and low temperature. DkLOX3 was expressed mainly in mature fruit, and the expression was extremely high throughout the storage period, apparently up-regulated by mechanical damage and high carbon dioxide treatments. Further functional analysis showed that overexpression of DkLOX3 in tomato (Solanum lycopersicum cv. Micro-Tom) accelerated fruit ripening and softening. This was accompanied by higher malondialdehyde (MDA) content and lycopene accumulation, advanced ethylene release peak and elevated expression of ethylene synthesis genes, including ACS2, ACO1, and ACO3. In addition, DkLOX3 overexpression promoted dark induced transgenic Arabidopsis leaf senescence with more chlorophyll loss, increased electrolyte leakage and MDA content. Furthermore, the functions of DkLOX3 in response to abiotic stresses, including osmotic stress, high salinity and drought were investigated. Arabidopsis DkLOX3 overexpression (DkLOX3-OX) transgenic lines were found to be more tolerant to osmotic stress with higher germination rate and root growth than wild-type. Moreover, DkLOX3-OX Arabidopsis plants also exhibited enhanced resistance to high salinity and drought, with similar decreased O2 (-) and H2O2 accumulation and upregulation of stress-responsive genes expression, including RD22, RD29A, RD29B, and NCED3, except for FRY1, which plays a negative role in stress response. Overall, these results suggested that DkLOX3 plays positive roles both in promoting ripening

  6. Abiotic Stress Monitoring, Forecasting and Management System

    OpenAIRE

    Gutam, Sridhar; Jain, Rajni; Rao, DVKN; Pannikkar, Preetha; Sarangi, A; Narula, Sapna

    2010-01-01

    The ill effects of abiotic factors like excess or deficient water availability, increase in temperature, climatic aberrations, soil salinity, sodicity, acidity, deficiency or toxicity of soil nutrients, pollution of water and soil are causing severe stress on the living organisms on the earth. Since long famers and soil scientists including plant breeders are aware that it is often the simultaneous occurrence of several abiotic stresses, rather than a particular stress condition, that is most...

  7. Genetic mapping of abiotic stress responses in sorghum

    Science.gov (United States)

    Due to rich genetic diversity for tolerance to various abiotic stress conditions, sorghum is an ideal system for genetic mapping and elucidation of genome regions that confer such response among cereal crops. Coupled with the development of DNA marker technologies and most recently the sequencing o...

  8. Heterologous Expression of MeLEA3: A 10 kDa Late Embryogenesis Abundant Protein of Cassava, Confers Tolerance to Abiotic Stress in Escherichia coli with Recombinant Protein Showing In Vitro Chaperone Activity.

    Science.gov (United States)

    Barros, Nicolle L F; da Silva, Diehgo T; Marques, Deyvid N; de Brito, Fabiano M; dos Reis, Savio P; de Souza, Claudia R B

    2015-01-01

    Late embryogenesis abundant (LEA) proteins are small molecular weight proteins involved in acquisition of tolerance to drought, salinity, high temperature, cold, and freezing stress in many plants. Previous studies revealed a cDNA sequence coding for a 10 kDa atypical LEA protein, named MeLEA3, predicted to be located into mitochondria with potential role in salt stress response of cassava (Manihot esculenta Crantz). Here we aimed to produce the recombinant MeLEA3 protein by heterologous expression in Escherichia coli and evaluate the tolerance of bacteria expressing this protein under abiotic stress. Our result revealed that the recombinant MeLEA3 protein conferred a protective function against heat and salt stress in bacterial cells. Also, the recombinant MeLEA3 protein showed in vitro chaperone activity by protection of NdeI restriction enzyme activity under heat stress.

  9. Molecular and physiological responses to abiotic stress in forest trees and their relevance to tree improvement.

    Science.gov (United States)

    Harfouche, Antoine; Meilan, Richard; Altman, Arie

    2014-11-01

    Abiotic stresses, such as drought, salinity and cold, are the major environmental stresses that adversely affect tree growth and, thus, forest productivity, and play a major role in determining the geographic distribution of tree species. Tree responses and tolerance to abiotic stress are complex biological processes that are best analyzed at a systems level using genetic, genomic, metabolomic and phenomic approaches. This will expedite the dissection of stress-sensing and signaling networks to further support efficient genetic improvement programs. Enormous genetic diversity for stress tolerance exists within some forest-tree species, and due to advances in sequencing technologies the molecular genetic basis for this diversity has been rapidly unfolding in recent years. In addition, the use of emerging phenotyping technologies extends the suite of traits that can be measured and will provide us with a better understanding of stress tolerance. The elucidation of abiotic stress-tolerance mechanisms will allow for effective pyramiding of multiple tolerances in a single tree through genetic engineering. Here we review recent progress in the dissection of the molecular basis of abiotic stress tolerance in forest trees, with special emphasis on Populus, Pinus, Picea, Eucalyptus and Quercus spp. We also outline practices that will enable the deployment of trees engineered for abiotic stress tolerance to land owners. Finally, recommendations for future work are discussed.

  10. Crop wild relatives of pigeonpea [Cajanus cajan (L.) Millsp.]: Distributions, ex situ conservation status, and potential genetic resources for abiotic stress tolerance

    NARCIS (Netherlands)

    Khoury, C.K.; Castaneda-Alvarez, N.P.; Achicanoy, H.A.; Sosa, C.C.; Bernau, V.; Kassa, M.T.; Norton, S.L.; Maesen, L.; Upadhyaya, H.D.; Ramirez-Villegas, J.; Jarvis, A.; Struik, P.C.

    2015-01-01

    Pigeonpea [Cajanus cajan (L.) Millsp.] is a versatile, stress-tolerant, and nutritious grain legume, possessing traits of value for enhancing the sustainability of dry sub-tropical and tropical agricultural systems. The use of crop wild relatives (CWR) in pigeonpea breeding has been successful in pr

  11. Stress tolerant plants

    OpenAIRE

    2014-01-01

    [EN] The invention relates to transgenic plants and methods for modulating abscisic acid (ABA) perception and signal transduction in plants. The plants find use in increasing yield in plants, particularly under abiotic stress.

  12. Differential expression profiles of poplar MAP kinase kinases in response to abiotic stresses and plant hormones, and overexpression of PtMKK4 improves the drought tolerance of poplar.

    Science.gov (United States)

    Wang, Lei; Su, Hongyan; Han, Liya; Wang, Chuanqi; Sun, Yanlin; Liu, Fenghong

    2014-07-15

    Mitogen-activated protein kinase (MAPK) cascades are universal signal transduction modules that play essential roles in plant growth, development and stress response. MAPK kinases (MAPKKs), which link MAPKs and MAPKK kinases (MAPKKKs), are integral in mediating various stress responses in plants. However, to date few data about the roles of poplar MAPKKs in stress signal transduction are available. In this study, we performed a systemic analysis of poplar MAPKK gene family expression profiles in response to several abiotic stresses and stress-associated hormones. Furthermore, Populus trichocarpa MAPKK4 (PtMKK4) was chosen for functional characterization. Transgenic analysis showed that overexpression of the PtMKK4 gene remarkably enhanced drought stress tolerance in the transgenic poplar plants. The PtMKK4-overexpressing plants also exhibited much lower levels of H2O2 and higher antioxidant enzyme activity after exposure to drought stress compared to the wide type lines. Besides, some drought marker genes including PtP5CS, PtSUS3, PtLTP3 and PtDREB8 exhibited higher expression levels in the transgenic lines than in the wide type under drought conditions. This study provided valuable information for understanding the putative functions of poplar MAPKKs involved in important signaling pathways under different stress conditions.

  13. Identification of Abiotic Stress Responsive Genes from Indian High Altitude Lepidium latifolium L. (Short Communication

    Directory of Open Access Journals (Sweden)

    Sanjay Mohan Gupta

    2012-09-01

    Full Text Available Abiotic stresses are major environmental factors that periodically account for significant loss in crop productivity. In order to improve the abiotic stress tolerance in vegetable crops through transgenic approaches, authors isolated and cloned six up-regulated, LlaDREB1b (JN214345, LlaGPAT (JN398166, LlaNAC (FJ423495, LlaCIPK (FJ423496, LlaPR5 (GQ853409 and LlaIPK (FJ487575 and two down-regulated LlaRan (JN214347 and LlaDRT (JN214346 abiotic stress responsive genes from Indian high altitude Lepidium latifolium L. plant that that may be used for abiotic stress-tolerance engineering upon functional validation.Defence Science Journal, 2012, 62(5, pp.315-318, DOI:http://dx.doi.org/10.14429/dsj.62.1495

  14. A late embryogenesis abundant protein HVA1 regulated by an inducible promoter enhances root growth and abiotic stress tolerance in rice without yield penalty.

    Science.gov (United States)

    Chen, Yi-Shih; Lo, Shuen-Fang; Sun, Peng-Kai; Lu, Chung-An; Ho, Tuan-Hua D; Yu, Su-May

    2015-01-01

    Regulation of root architecture is essential for maintaining plant growth under adverse environment. A synthetic abscisic acid (ABA)/stress-inducible promoter was designed to control the expression of a late embryogenesis abundant protein (HVA1) in transgenic rice. The background of HVA1 is low but highly inducible by ABA, salt, dehydration and cold. HVA1 was highly accumulated in root apical meristem (RAM) and lateral root primordia (LRP) after ABA/stress treatments, leading to enhanced root system expansion. Water-use efficiency (WUE) and biomass also increased in transgenic rice, likely due to the maintenance of normal cell functions and metabolic activities conferred by HVA1 which is capable of stabilizing proteins, under osmotic stress. HVA1 promotes lateral root (LR) initiation, elongation and emergence and primary root (PR) elongation via an auxin-dependent process, particularly by intensifying asymmetrical accumulation of auxin in LRP founder cells and RAM, even under ABA/stress-suppressive conditions. We demonstrate a successful application of an inducible promoter in regulating the spatial and temporal expression of HVA1 for improving root architecture and multiple stress tolerance without yield penalty.

  15. Structure, function and networks of transcription factors involved in abiotic stress responses

    DEFF Research Database (Denmark)

    Lindemose, Søren; O'Shea, Charlotte; Jensen, Michael Krogh

    2013-01-01

    and the phytohormone ABA. Although ectopic expression of several TFs has improved abiotic stress tolerance in plants, fine-tuning of TF expression and protein levels remains a challenge to avoid crop yield loss. To further our understanding of TFs in abiotic stress responses, emerging gene regulatory networks based...... on TFs and their direct targets genes are presented. These revealed components shared between ABA-dependent and independent signaling as well as abiotic and biotic stress signaling. Protein structure analysis suggested that TFs hubs of large interactomes have extended regions with protein intrinsic...

  16. A review on possible elicitor molecules of cyanobacteria: their role in improving plant growth and providing tolerance against biotic or abiotic stress.

    Science.gov (United States)

    Singh, S

    2014-11-01

    Cyanobacteria are prominent inhabitants of many agricultural soils, where they potentially contribute towards biological nitrogen fixation, help in phosphate solubilization and mineral release to improve soil fertility and crop productivity. However, beside naturally fertilizing and balancing mineral nutrition in the soil, many cyanobacteria are known to release various kinds of biologically active substances like proteins, vitamins, carbohydrates, amino acids, polysaccharides and phytohormones that function as elicitor molecules to promote plant growth and help them to fight against biotic and abiotic stress. These metabolites produced by the cyanobacteria affect the gene expression of the host plants and thereby bring about qualitative and quantitative changes in the phytochemical composition of the plants. Experiments carried out with live inoculum or with the extracts of cyanobacterial strains on several plant species, such as rice, wheat, maize, cotton etc., have demonstrated the synthesis of signalling metabolites. Thus, in view of its beneficial effect, this paper reviews the role of cyanobacteria in triggering the growth and development of plants and hence its utilization in agriculture.

  17. Reverse engineering: a key component of systems biology to unravel global abiotic stress cross-talk.

    Science.gov (United States)

    Friedel, Swetlana; Usadel, Björn; von Wirén, Nicolaus; Sreenivasulu, Nese

    2012-01-01

    Understanding the global abiotic stress response is an important stepping stone for the development of universal stress tolerance in plants in the era of climate change. Although co-occurrence of several stress factors (abiotic and biotic) in nature is found to be frequent, current attempts are poor to understand the complex physiological processes impacting plant growth under combinatory factors. In this review article, we discuss the recent advances of reverse engineering approaches that led to seminal discoveries of key candidate regulatory genes involved in cross-talk of abiotic stress responses and summarized the available tools of reverse engineering and its relevant application. Among the universally induced regulators involved in various abiotic stress responses, we highlight the importance of (i) abscisic acid (ABA) and jasmonic acid (JA) hormonal cross-talks and (ii) the central role of WRKY transcription factors (TF), potentially mediating both abiotic and biotic stress responses. Such interactome networks help not only to derive hypotheses but also play a vital role in identifying key regulatory targets and interconnected hormonal responses. To explore the full potential of gene network inference in the area of abiotic stress tolerance, we need to validate hypotheses by implementing time-dependent gene expression data from genetically engineered plants with modulated expression of target genes. We further propose to combine information on gene-by-gene interactions with data from physical interaction platforms such as protein-protein or TF-gene networks.

  18. Regulation of Translation Initiation under Biotic and Abiotic Stresses

    Directory of Open Access Journals (Sweden)

    Ana B. Castro-Sanz

    2013-02-01

    Full Text Available Plants have developed versatile strategies to deal with the great variety of challenging conditions they are exposed to. Among them, the regulation of translation is a common target to finely modulate gene expression both under biotic and abiotic stress situations. Upon environmental challenges, translation is regulated to reduce the consumption of energy and to selectively synthesize proteins involved in the proper establishment of the tolerance response. In the case of viral infections, the situation is more complex, as viruses have evolved unconventional mechanisms to regulate translation in order to ensure the production of the viral encoded proteins using the plant machinery. Although the final purpose is different, in some cases, both plants and viruses share common mechanisms to modulate translation. In others, the mechanisms leading to the control of translation are viral- or stress-specific. In this paper, we review the different mechanisms involved in the regulation of translation initiation under virus infection and under environmental stress in plants. In addition, we describe the main features within the viral RNAs and the cellular mRNAs that promote their selective translation in plants undergoing biotic and abiotic stress situations.

  19. 苹果MdMYB121基因异位表达提高烟草的抗逆性%Ectopic Expression of MdMYB121 Gene Enhances Tolerance to Abiotic Stresses in Tobacco

    Institute of Scientific and Technical Information of China (English)

    曹忠慧; 王荣凯; 郝玉金

    2013-01-01

    苹果MdMYB121(序列号MDP0000196982)蛋白具有典型的R2R3MYB结构域,半定量RT-PCR检测发现,MdMYB1 21表达能被多种非生物胁迫和逆境相关激素不同程度地诱导.采用RT-PCR技术克隆出该基因的全长eDNA,构建其表达载体并侵染烟草,获得转基因植株.表型分析发现,与野生型对照相比,转基因烟草的种子萌发对盐胁迫不敏感,幼苗的抗盐性也得到明显提高;相对于野生型幼苗,转基因幼苗生长对水杨酸(SA)处理不敏感,根和茎较长,侧根更多.转基因烟草植株对高盐、干旱和低温的抗性比野生型对照明显提高.表明MdMYB121能够响应非生物胁迫,在植物抵抗非生物胁迫中具有重要功能.%Apple MdMYB121 (sequence ID MDP0000196982) protein has typical R2R3MYB domains.Semi-quantitative RT-PCR analysis showed that MdMYB121 gene was induced by various abiotic stresses and stress-related hormones to different extents.The full-cDNA of MdMYB121 gene was amplified with RT-PCR and inserted downstream Cauliflower mosaic virus 35S CaMV promoter into an expression vector pBI121.Subsequently,it was genetically transformed into tobacco.Three transgenic tobacco lines were used for further investigation.The result showed that the seed germination and seedling growth of transgenic lines were more insensitive to high salinity than the WT control.In addition,the growth of transgenic seedlings was also less insensitive to salicylic acid (SA) than the WT control,as indicated with longer roots,hypocotyls,and more lateral roots in transgenic lines than WT.Finally,abiotic stresses tolerance assays were conducted for transgenic plants in soil.The result showed that transgenic plants were more tolerant to high salinity,drought and cold than the WT control.Therefore,MdMYB121 is induced by multiple abiotic stresses,and is involved in the responses to and the fight against abiotic stresses.

  20. Identification of Cassava MicroRNAs under Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Carolina Ballén-Taborda

    2013-01-01

    Full Text Available The study of microRNAs (miRNAs in plants has gained significant attention in recent years due to their regulatory role during development and in response to biotic and abiotic stresses. Although cassava (Manihot esculenta Crantz is tolerant to drought and other adverse conditions, most cassava miRNAs have been predicted using bioinformatics alone or through sequencing of plants challenged by biotic stress. Here, we use high-throughput sequencing and different bioinformatics methods to identify potential cassava miRNAs expressed in different tissues subject to heat and drought conditions. We identified 60 miRNAs conserved in other plant species and 821 potential cassava-specific miRNAs. We also predicted 134 and 1002 potential target genes for these two sets of sequences. Using real time PCR, we verified the condition-specific expression of 5 cassava small RNAs relative to a non-stress control. We also found, using publicly available expression data, a significantly lower expression of the predicted target genes of conserved and nonconserved miRNAs under drought stress compared to other cassava genes. Gene Ontology enrichment analysis along with condition specific expression of predicted miRNA targets, allowed us to identify several interesting miRNAs which may play a role in stress-induced posttranscriptional regulation in cassava and other plants.

  1. STRESS ECOLOGY IN FUCUS : ABIOTIC, BIOTIC AND GENETIC INTERACTIONS

    NARCIS (Netherlands)

    Wahl, Martin; Jormalainen, Veijo; Eriksson, Britas Klemens; Coyer, James A.; Molis, Markus; Schubert, Hendrik; Dethier, Megan; Karez, Rolf; Kruse, Inken; Lenz, Mark; Pearson, Gareth; Rohde, Sven; Wikstrom, Sofia A.; Olsen, Jeanine L.; Lesser, M

    2011-01-01

    Stress regimes defined as the synchronous or sequential action of abiotic and biotic stresses determine the performance and distribution of species. The natural patterns of stress to which species are more or less well adapted have recently started to shift and alter under the influence of global ch

  2. Nitric Oxide Signaling in Plant Responses to Abiotic Stresses

    Institute of Scientific and Technical Information of China (English)

    Weihua Qiao; LiuMin Fan

    2008-01-01

    Nitric oxide (NO) plays important roles in diverse physiological processes In plants. NO can provoke both beneficial and harmful effects, which depend on the concentration and location of NO in plant cells. This review is focused on NO synthesis and the functions of NO in plant responses to abiotic environmental stresses. Abiotic stresses mostly induce NO production in plants. NO alleviates the harmfulness of reactive oxygen species, and reacts with other target molecules, and regulates the expression of stress responsive genes under various stress conditions.

  3. Enhancing crop resilience to combined abiotic and biotic stress through the dissection of physiological and molecular crosstalk.

    Science.gov (United States)

    Kissoudis, Christos; van de Wiel, Clemens; Visser, Richard G F; van der Linden, Gerard

    2014-01-01

    Plants growing in their natural habitats are often challenged simultaneously by multiple stress factors, both abiotic and biotic. Research has so far been limited to responses to individual stresses, and understanding of adaptation to combinatorial stress is limited, but indicative of non-additive interactions. Omics data analysis and functional characterization of individual genes has revealed a convergence of signaling pathways for abiotic and biotic stress adaptation. Taking into account that most data originate from imposition of individual stress factors, this review summarizes these findings in a physiological context, following the pathogenesis timeline and highlighting potential differential interactions occurring between abiotic and biotic stress signaling across the different cellular compartments and at the whole plant level. Potential effects of abiotic stress on resistance components such as extracellular receptor proteins, R-genes and systemic acquired resistance will be elaborated, as well as crosstalk at the levels of hormone, reactive oxygen species, and redox signaling. Breeding targets and strategies are proposed focusing on either manipulation and deployment of individual common regulators such as transcription factors or pyramiding of non- (negatively) interacting components such as R-genes with abiotic stress resistance genes. We propose that dissection of broad spectrum stress tolerance conferred by priming chemicals may provide an insight on stress cross regulation and additional candidate genes for improving crop performance under combined stress. Validation of the proposed strategies in lab and field experiments is a first step toward the goal of achieving tolerance to combinatorial stress in crops.

  4. Enhancing crop resilience to combined abiotic and biotic stress through the dissection of physiological and molecular crosstalk

    Directory of Open Access Journals (Sweden)

    Christos eKissoudis

    2014-05-01

    Full Text Available Plants growing in their natural habitats are often challenged simultaneously by multiple stress factors, both abiotic and biotic. Research has so far been limited to responses to individual stresses, and understanding of adaptation to combinatorial stress is limited, but indicative of non-additive interactions. Omics data analysis and functional characterization of individual genes has revealed a convergence of signalling pathways for abiotic and biotic stress adaptation. Taking into account that most data originate from imposition of individual stress factors, this review summarizes these findings in a physiological context, following the pathogenesis timeline and highlighting potential differential interactions occurring between abiotic and biotic stress signalling across the different cellular compartments and at the whole plant level. Potential effects of abiotic stress on resistance components such as extracellular receptor proteins, R-genes and systemic acquired resistance will be elaborated, as well as crosstalk at the levels of hormone, ROS and redox signalling. Breeding targets and strategies are proposed focusing on either manipulation and deployment of individual common regulators such as transcription factors or pyramiding of non- (negatively interacting components such as R-genes with abiotic stress resistance genes. We propose that dissection of broad spectrum stress tolerance conferred by priming chemicals may provide an insight on stress cross regulation and additional candidate genes for improving crop performance under combined stress. Validation of the proposed strategies in lab and field experiments is a first step towards the goal of achieving tolerance to combinatorial stress in crops.

  5. Ecogenomics of plant resistance to biotic and abiotic stresses

    NARCIS (Netherlands)

    Davila Olivas, N.H.

    2016-01-01

    Summary

    In natural and agricultural ecosystems, plants are exposed to a wide diversity of abiotic and biotic stresses such as drought, salinity, pathogens and insect herbivores. Under natural conditions, these stresses do not occur in isolation but commonly occur simultaneo

  6. Identification of plant genes for abiotic stress resistance

    OpenAIRE

    Dixit, S.A.

    2008-01-01

    As water and salt stresses occur frequently and can affect many habitats, plants have developed several strategies to cope with these challenges: either adaptation mechanisms, which allow them to survive the adverse conditions, or specific growth habits to avoid stress conditions. Stress-tolerant plants have evolved certain adaptive mechanisms to display different degrees of tolerance, which are largely determined by genetic plasticity. Differential stress tolerance could be attributed to dif...

  7. Comprehensive Analysis Suggests Overlapping Expression of Rice ONAC Transcription Factors in Abiotic and Biotic Stress Responses

    Directory of Open Access Journals (Sweden)

    Lijun Sun

    2015-02-01

    Full Text Available NAC (NAM/ATAF/CUC transcription factors comprise a large plant-specific gene family that contains more than 149 members in rice. Extensive studies have revealed that NAC transcription factors not only play important roles in plant growth and development, but also have functions in regulation of responses to biotic and abiotic stresses. However, biological functions for most of the members in the NAC family remain unknown. In this study, microarray data analyses revealed that a total of 63 ONAC genes exhibited overlapping expression patterns in rice under various abiotic (salt, drought, and cold and biotic (infection by fungal, bacterial, viral pathogens, and parasitic plants stresses. Thirty-eight ONAC genes exhibited overlapping expression in response to any two abiotic stresses, among which 16 of 30 selected ONAC genes were upregulated in response to exogenous ABA. Sixty-five ONAC genes showed overlapping expression patterns in response to any two biotic stresses. Results from the present study suggested that members of the ONAC genes with overlapping expression pattern may have pleiotropic biological functions in regulation of defense response against different abiotic and biotic stresses, which provide clues for further functional analysis of the ONAC genes in stress tolerance and pathogen resistance.

  8. Compartment specific importance of glutathione during abiotic and biotic stress

    Directory of Open Access Journals (Sweden)

    Bernd eZechmann

    2014-10-01

    Full Text Available The tripeptide thiol glutathione (γ-L-glutamyl-L-cysteinyl-glycine is the most important sulfur containing antioxidant in plants and essential for plant defense against abiotic and biotic stress conditions. It is involved in the detoxification of reactive oxygen species, redox signaling, the modulation of defense gene expression and important for the regulation of enzymatic activities. Even though changes in glutathione contents are well documented in plants and its roles in plant defense are well established, still too little is known about its compartment specific importance during abiotic and biotic stress conditions. Due to technical advances in the visualization of glutathione and the redox state of plants through microscopical methods some progress was made in the last few years in studying the importance of subcellular glutathione contents during stress conditions in plants. This review summarizes the data available on compartment specific importance of glutathione in the protection against abiotic and biotic stress conditions such as high light stress, exposure to cadmium, drought, and pathogen attack (Pseudomonas, Botrytis, Tobacco Mosaic Virus. The data will be discussed in connection with the subcellular accumulation of ROS during these conditions and glutathione synthesis which are both highly compartment specific (e.g. glutathione synthesis takes place in chloroplasts and the cytosol. Thus this review will reveal the compartment specific importance of glutathione during abiotic and biotic stress conditions.

  9. Sterility Caused by Floral Organ Degeneration and Abiotic Stresses in Arabidopsis and Cereal Grains

    Directory of Open Access Journals (Sweden)

    Ashley Rae Smith

    2016-10-01

    Full Text Available Natural floral organ degeneration or abortion results in unisexual or fully sterile flowers, while abiotic stresses lead to sterility after initiation of floral reproductive organs. Since normal flower development is essential for plant sexual reproduction and crop yield, it is imperative to have a better understanding of plant sterility under regular and stress conditions. Here, we review the functions of ABC genes together with their downstream genes in floral organ degeneration and the formation of unisexual flowers in Arabidopsis and several agriculturally significant cereal grains. We further explore the roles of hormones, including auxin, brassinosteroids, jasmonic acid, gibberellic acid, and ethylene, in floral organ formation and fertility. We show that alterations in genes affecting hormone biosynthesis, hormone transport and perception cause loss of stamens/carpels, abnormal floral organ development, poor pollen production, which consequently result in unisexual flowers and male/female sterility. Moreover, abiotic stresses, such as heat, cold, and drought, commonly affect floral organ development and fertility. Sterility is induced by abiotic stresses mostly in male floral organ development, particularly during meiosis, tapetum development, anthesis, dehiscence, and fertilization. A variety of genes including those involved in heat shock, hormone signaling, cold tolerance, metabolisms of starch and sucrose, meiosis, and tapetum development are essential for plants to maintain normal fertility under abiotic stress conditions. Further elucidation of cellular, biochemical and molecular mechanisms about regulation of fertility will improve yield and quality for many agriculturally valuable crops.

  10. Exploration of wild relatives of tomato for enhanced stress tolerance

    NARCIS (Netherlands)

    Junming Li,

    2010-01-01

    Among the different abiotic and biotic stresses, Botrytis cinerea, Phytophthora infestans and high salt concentrations are world-wide the most destructive. Several wild relatives of tomato were identified as source for tolerance to these stresses. Three introgression line (IL) populations derived fr

  11. Cell Wall Metabolism in Response to Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Hyacinthe Le Gall

    2015-02-01

    Full Text Available This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic, transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i an increased level in xyloglucan endotransglucosylase/hydrolase (XTH and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions.

  12. Genes Acting on Transcriptional Control during Abiotic Stress Responses

    Directory of Open Access Journals (Sweden)

    Glacy Jaqueline da Silva

    2014-01-01

    Full Text Available Abiotic stresses are the major cause of yield loss in crops around the world. Greater genetic gains are possible by combining the classical genetic improvement with advanced molecular biology techniques. The understanding of mechanisms triggered by plants to meet conditions of stress is of fundamental importance for the elucidation of these processes. Current genetically modified crops help to mitigate the effects of these stresses, increasing genetic gains in order to supply the agricultural market and the demand for better quality food throughout the world. To obtain safe genetic modified organisms for planting and consumption, a thorough grasp of the routes and genes that act in response to these stresses is necessary. This work was developed in order to collect important information about essential TF gene families for transcriptional control under abiotic stress responses.

  13. Involvement of Histone Modifications in Plant Abiotic Stress Responses

    Institute of Scientific and Technical Information of China (English)

    Lianyu Yuan; Xuncheng Liu; Ming Luo; Songguang Yang; Keqiang Wu

    2013-01-01

    As sessile organisms, plants encounter various environmental stimuli including abiotic stresses during their lifecycle. To survive under adverse conditions, plants have evolved intricate mechanisms to perceive external signals and respond accordingly. Responses to various stresses largely depend on the plant capacity to modulate the transcriptome rapidly and specifically. A number of studies have shown that the molecular mechanisms driving the responses of plants to environmental stresses often depend on nucleosome histone post-translational modifications including histone acetylation, methylation, ubiquitination, and phosphorylation. The combined effects of these modifications play an essential role in the regulation of stress responsive gene expression. In this review, we highlight our current understanding of the epigenetic mechanisms of histone modifications and their roles in plant abiotic stress response.

  14. Seed treatment with Trichoderma harzianum alleviates biotic, abiotic, and physiological stresses in germinating seeds and seedlings.

    Science.gov (United States)

    Mastouri, Fatemeh; Björkman, Thomas; Harman, Gary E

    2010-11-01

    Trichoderma spp. are endophytic plant symbionts that are widely used as seed treatments to control diseases and to enhance plant growth and yield. Although some recent work has been published on their abilities to alleviate abiotic stresses, specific knowledge of mechanisms, abilities to control multiple plant stress factors, their effects on seed and seedlings is lacking. We examined the effects of seed treatment with T. harzianum strain T22 on germination of seed exposed to biotic stress (seed and seedling disease caused by Pythium ultimum) and abiotic stresses (osmotic, salinity, chilling, or heat stress). We also evaluated the ability of the beneficial fungus to overcome physiological stress (poor seed quality induced by seed aging). If seed were not under any of the stresses noted above, T22 generally had little effect upon seedling performance. However, under stress, treated seed germinated consistently faster and more uniformly than untreated seeds whether the stress was osmotic, salt, or suboptimal temperatures. The consistent response to varying stresses suggests a common mechanism through which the plant-fungus association enhances tolerance to a wide range of abiotic stresses as well as biotic stress. A common factor that negatively affects plants under these stress conditions is accumulation of toxic reactive oxygen species (ROS), and we tested the hypothesis that T22 reduced damages resulting from accumulation of ROS in stressed plants. Treatment of seeds reduced accumulation of lipid peroxides in seedlings under osmotic stress or in aged seeds. In addition, we showed that the effect of exogenous application of an antioxidant, glutathione, or application of T22, resulted in a similar positive effect on seed germination under osmotic stress or in aged seed. This evidence supports the model that T. harzianum strain T22 increases seedling vigor and ameliorates stress by inducing physiological protection in plants against oxidative damage.

  15. Ecogenomics of plant resistance to biotic and abiotic stresses

    OpenAIRE

    Davila Olivas, N.H.

    2016-01-01

    Summary In natural and agricultural ecosystems, plants are exposed to a wide diversity of abiotic and biotic stresses such as drought, salinity, pathogens and insect herbivores. Under natural conditions, these stresses do not occur in isolation but commonly occur simultaneously. However, plants have developed sophisticated mechanisms to survive and reproduce under suboptimal conditions. Genetic screenings and molecular genetic assays have shed light on the molecular players that provide resis...

  16. Silicon: a duo synergy for regulating crop growth and hormonal signaling under abiotic stress conditions.

    Science.gov (United States)

    Kim, Yoon-Ha; Khan, Abdul Latif; Lee, In-Jung

    2016-12-01

    Abiotic stresses, such as salinity, heavy metals and drought, are some of the most devastating factors hindering sustainable crop production today. Plants use their own defensive strategies to cope with the adverse effects of these stresses, via the regulation of the expression of essential phytohormones, such as gibberellins (GA), salicylic acid (SA), jasmonates (JA), abscisic acid (ABA) and ethylene (ET). However, the efficacy of the endogenous defensive arsenals of plants often falls short if the stress persists over an extended period. Various strategies are developed to improve stress tolerance in plants. For example, silicon (Si) is widely considered to possess significant potential as a substance which ameliorate the negative effects of abiotic stresses, and improves plant growth and biomass accumulation. This review aims to explain how Si application influences the signaling of the endogenous hormones GA, SA, ABA, JA and ET during salinity, wounding, drought and metal stresses in crop plants. Phytohormonal cross talk plays an important role in the regulation of induced defences against stress. However, detailed molecular and proteomic research into these interactions is needed in order to identify the underlying mechanisms of stress tolerance that is imparted by Si application and uptake.

  17. The Plant Heat Stress Transcription Factors (HSFs): Structure, Regulation, and Function in Response to Abiotic Stresses.

    Science.gov (United States)

    Guo, Meng; Liu, Jin-Hong; Ma, Xiao; Luo, De-Xu; Gong, Zhen-Hui; Lu, Ming-Hui

    2016-01-01

    Abiotic stresses such as high temperature, salinity, and drought adversely affect the survival, growth, and reproduction of plants. Plants respond to such unfavorable changes through developmental, physiological, and biochemical ways, and these responses require expression of stress-responsive genes, which are regulated by a network of transcription factors (TFs), including heat stress transcription factors (HSFs). HSFs play a crucial role in plants response to several abiotic stresses by regulating the expression of stress-responsive genes, such as heat shock proteins (Hsps). In this review, we describe the conserved structure of plant HSFs, the identification of HSF gene families from various plant species, their expression profiling under abiotic stress conditions, regulation at different levels and function in abiotic stresses. Despite plant HSFs share highly conserved structure, their remarkable diversification across plants reflects their numerous functions as well as their integration into the complex stress signaling and response networks, which can be employed in crop improvement strategies via biotechnological intervention.

  18. The plant heat stress transcription factors (HSFs: structure, regulation and function in response to abiotic stresses

    Directory of Open Access Journals (Sweden)

    Meng eGuo

    2016-02-01

    Full Text Available Abiotic stresses such as high temperature, salinity and drought adversely affect the survival, growth and reproduction of plants. Plants respond to such unfavorable changes through developmental, physiological and biochemical ways, and these responses require expression of stress-responsive genes, which are regulated by a network of transcription factors (TFs, including heat stress transcription factors (HSFs. HSFs play a crucial role in plants response to several abiotic stresses by regulating the expression of stress-responsive genes, such as heat shock proteins (Hsps. In this review, we describe the conserved structure of plant HSFs, the identification of HSF gene families from various plant species, their expression profiling under abiotic stress conditions, regulation at different levels and function in abiotic stresses. Despite plant HSFs share highly conserved structure, their remarkable diversification across plants reflects their numerous functions as well as their integration into the complex stress signaling and response networks, which can be employed in crop improvement strategies via biotechnological intervention.

  19. Identification of Discriminant Factors after Exposure of Maize and Common Bean Plantlets to Abiotic Stresses

    Directory of Open Access Journals (Sweden)

    Lázaro HERNÁNDEZ

    2015-12-01

    Full Text Available Adverse environmental conditions limit crop yield and better understanding of plant response to stress will assist the development of more tolerant cultivars. Maize and common bean plantlets were evaluated under salinity, high temperature, drought and waterlogged conditions to identify biochemical markers which could be useful for rapid identification of putative stress tolerant plants. The levels of phenolics (free, cell wall-linked, total, aldehydes including malondialdehyde and chlorophylls (a, b, total were measured on stressed plantlets.  Only two indicators were statistically non-significant:  chlorophyll b in maize plantlets stressed with sodium chloride and malondialdehyde content in drought stressed maize. The most remarkable effects of abiotic stresses can be summarized as follows: (i salinity increased levels of free phenolics in maize plantlets and chlorophylls (a, b, total in common bean; (ii high temperature (40 °C elevated levels of chlorophylls (a, b, total in maize but decreased chlorophylls (a, b, total and free phenolics in common bean; (iii drought increased phenolics and decreased chlorophylls (a, b, total in maize and increased chlorophyll pigments (a, b, total in common bean; (iv waterlogging increased free phenolics and decreased chlorophylls (a, b, total in maize and increased chlorophyll (a, total in common bean. Free phenolics and chlorophylls, especially a, were the most responsive indicators to stress and can, therefore, be considered putative biochemical markers for abiotic stress tolerance in maize and common bean. The use of Fisher’s linear discriminant analysis to differentiate non-stressed and stressed plants in breeding programs is also a novel aspect of this report. Fisher’s linear discriminant functions classified correctly 100% of non-stressed or stressed originally grouped plants.

  20. Natural variation in abiotic stress responsive gene expression and local adaptation to climate in Arabidopsis thaliana.

    Science.gov (United States)

    Lasky, Jesse R; Des Marais, David L; Lowry, David B; Povolotskaya, Inna; McKay, John K; Richards, James H; Keitt, Timothy H; Juenger, Thomas E

    2014-09-01

    Gene expression varies widely in natural populations, yet the proximate and ultimate causes of this variation are poorly known. Understanding how variation in gene expression affects abiotic stress tolerance, fitness, and adaptation is central to the field of evolutionary genetics. We tested the hypothesis that genes with natural genetic variation in their expression responses to abiotic stress are likely to be involved in local adaptation to climate in Arabidopsis thaliana. Specifically, we compared genes with consistent expression responses to environmental stress (expression stress responsive, "eSR") to genes with genetically variable responses to abiotic stress (expression genotype-by-environment interaction, "eGEI"). We found that on average genes that exhibited eGEI in response to drought or cold had greater polymorphism in promoter regions and stronger associations with climate than those of eSR genes or genomic controls. We also found that transcription factor binding sites known to respond to environmental stressors, especially abscisic acid responsive elements, showed significantly higher polymorphism in drought eGEI genes in comparison to eSR genes. By contrast, eSR genes tended to exhibit relatively greater pairwise haplotype sharing, lower promoter diversity, and fewer nonsynonymous polymorphisms, suggesting purifying selection or selective sweeps. Our results indicate that cis-regulatory evolution and genetic variation in stress responsive gene expression may be important mechanisms of local adaptation to climatic selective gradients.

  1. Transcriptional networks-crops, clocks, and abiotic stress.

    Science.gov (United States)

    Gehan, Malia A; Greenham, Kathleen; Mockler, Todd C; McClung, C Robertson

    2015-04-01

    Several factors affect the yield potential and geographical range of crops including the circadian clock, water availability, and seasonal temperature changes. In order to sustain and increase plant productivity on marginal land in the face of both biotic and abiotic stresses, we need to more efficiently generate stress-resistant crops through marker-assisted breeding, genetic modification, and new genome-editing technologies. To leverage these strategies for producing the next generation of crops, future transcriptomic data acquisition should be pursued with an appropriate temporal design and analyzed with a network-centric approach. The following review focuses on recent developments in abiotic stress transcriptional networks in economically important crops and will highlight the utility of correlation-based network analysis and applications.

  2. Using Phenomic Analysis of Photosynthetic Function for Abiotic Stress Response Gene Discovery

    KAUST Repository

    Rungrat, Tepsuda

    2016-09-09

    Monitoring the photosynthetic performance of plants is a major key to understanding how plants adapt to their growth conditions. Stress tolerance traits have a high genetic complexity as plants are constantly, and unavoidably, exposed to numerous stress factors, which limits their growth rates in the natural environment. Arabidopsis thaliana, with its broad genetic diversity and wide climatic range, has been shown to successfully adapt to stressful conditions to ensure the completion of its life cycle. As a result, A. thaliana has become a robust and renowned plant model system for studying natural variation and conducting gene discovery studies. Genome wide association studies (GWAS) in restructured populations combining natural and recombinant lines is a particularly effective way to identify the genetic basis of complex traits. As most abiotic stresses affect photosynthetic activity, chlorophyll fluorescence measurements are a potential phenotyping technique for monitoring plant performance under stress conditions. This review focuses on the use of chlorophyll fluorescence as a tool to study genetic variation underlying the stress tolerance responses to abiotic stress in A. thaliana.

  3. Coordinating metabolite changes with our perception of plant abiotic stress responses: emerging views revealed by integrative-omic analyses.

    Science.gov (United States)

    Radomiljac, Jordan D; Whelan, James; van der Merwe, Margaretha

    2013-09-06

    Metabolic configuration and adaptation under a range of abiotic stresses, including drought, heat, salinity, cold, and nutrient deprivation, are subjected to an intricate span of molecular pathways that work in parallel in order to enhance plant fitness and increase stress tolerance. In recent years, unprecedented advances have been made in identifying and linking different abiotic stresses, and the current challenge in plant molecular biology is deciphering how the signaling responses are integrated and transduced throughout metabolism. Metabolomics have often played a fundamental role in elucidating the distinct and overlapping biochemical changes that occur in plants. However, a far greater understanding and appreciation of the complexity in plant metabolism under specific stress conditions have become apparent when combining metabolomics with other-omic platforms. This review focuses on recent advances made in understanding the global changes occurring in plant metabolism under abiotic stress conditions using metabolite profiling as an integrated discovery platform.

  4. Role of brassinosteroid in plant adaptation to abiotic stresses and its interplay with other hormones.

    Science.gov (United States)

    Ahammed, Golam J; Xia, Xiao-Jian; Li, Xin; Shi, Kai; Yu, Jing-Quan; Zhou, Yan-Hong

    2015-01-01

    Brassinosteroids (BRs) are ubiquitous plant steroid hormones, playing diverse roles in plant growth, development and stress responses. Defects in BRs biosynthesis or signaling result in physiologic and phenotypic abnormalities. To date, numerous studies have highlighted BRs-induced stress tolerance to various environmental extremes such as high temperature, chilling, drought, salinity and heavy metals in a range of plant species. However, the in-depth mechanisms of BRs-induced stress tolerance still remain largely unknown. It is now clear that BRs-induced stress responses are strictly concentration dependent and the optimal concentration for improving the plant adaptability may vary depending on the plant species, developmental stages and environmental conditions as well. Conflicting evidences concerning regulation of stress adaptation by BRs demand further elucidation of mechanism of BRs action in response to environmental stresses in plants. Recent advances in phytohormone research suggest that the effect of BRs on stress tolerance relies largely on its interplay with other hormones. In this review, we critically analyze the multifaceted roles of BRs in various abiotic stresses and its potential crosstalk with other hormones in stress adaptation. The discrepancy in the dose and mode of application of BRs analogues for stress management is also discussed.

  5. Stress tolerance in plants via habitat-adapted symbiosis.

    Science.gov (United States)

    Rodriguez, Rusty J; Henson, Joan; Van Volkenburgh, Elizabeth; Hoy, Marshal; Wright, Leesa; Beckwith, Fleur; Kim, Yong-Ok; Redman, Regina S

    2008-04-01

    We demonstrate that native grass species from coastal and geothermal habitats require symbiotic fungal endophytes for salt and heat tolerance, respectively. Symbiotically conferred stress tolerance is a habitat-specific phenomenon with geothermal endophytes conferring heat but not salt tolerance, and coastal endophytes conferring salt but not heat tolerance. The same fungal species isolated from plants in habitats devoid of salt or heat stress did not confer these stress tolerances. Moreover, fungal endophytes from agricultural crops conferred disease resistance and not salt or heat tolerance. We define habitat-specific, symbiotically-conferred stress tolerance as habitat-adapted symbiosis and hypothesize that it is responsible for the establishment of plants in high-stress habitats. The agricultural, coastal and geothermal plant endophytes also colonized tomato (a model eudicot) and conferred disease, salt and heat tolerance, respectively. In addition, the coastal plant endophyte colonized rice (a model monocot) and conferred salt tolerance. These endophytes have a broad host range encompassing both monocots and eudicots. Interestingly, the endophytes also conferred drought tolerance to plants regardless of the habitat of origin. Abiotic stress tolerance correlated either with a decrease in water consumption or reactive oxygen sensitivity/generation but not to increased osmolyte production. The ability of fungal endophytes to confer stress tolerance to plants may provide a novel strategy for mitigating the impacts of global climate change on agricultural and native plant communities.

  6. The influence of Plant Growth Promoting Rhizobacteria (PGPR on the reduction of abiotic stresses in crops

    Directory of Open Access Journals (Sweden)

    Omid Alizadeh

    2011-12-01

    Full Text Available Plants are always subjected to biotic and abiotic stresses in the environment which haveinfluences on the growth and development of the plants. Beneficial free-living soil bacteria are usuallyreferred as Plant-Growth Promoting Rhizobacteria or PGPR. Different plant growth-promotingRhizosphere bacteria, including associative bacteria such as: Azospirillum, Bacillus, Pseudomonas andEnterobacter group have been used for their beneficial influences on plants. Typically, PGPRs areassociated with plants root and augment plant productivity and immunity; however, recent worksshowed that PGPRs not have just induced the systemic tolerance to abiotic stress such as salt anddrought, but also they have increased the nutrient uptake from soils, and as a result the hazardousaccumulation of nitrates and phosphates in the agricultural soils can be reduced by usage of them.

  7. Regulation of abiotic and biotic stress responses by plant hormones

    DEFF Research Database (Denmark)

    Grosskinsky, Dominik Kilian; van der Graaff, Eric; Roitsch, Thomas Georg

    2016-01-01

    Plant hormones (phytohormones) are signal molecules produced within the plant, and occur in very low concentrations. In the present chapter, the current knowledge on the regulation of biotic and biotic stress responses by plant hormones is summarized with special focus on the novel insights into ...... through ubiquitination. The wide range of biotic and abiotic stresses that affect crop plants limits agricultural production.......Plant hormones (phytohormones) are signal molecules produced within the plant, and occur in very low concentrations. In the present chapter, the current knowledge on the regulation of biotic and biotic stress responses by plant hormones is summarized with special focus on the novel insights...

  8. Identification of plant genes for abiotic stress resistance

    NARCIS (Netherlands)

    Dixit, S.A.

    2008-01-01

    As water and salt stresses occur frequently and can affect many habitats, plants have developed several strategies to cope with these challenges: either adaptation mechanisms, which allow them to survive the adverse conditions, or specific growth habits to avoid stress conditions. Stress-tolerant pl

  9. Brassinosteroids make plant life easier under abiotic stresses mainly by modulating major components of antioxidant defense system

    Directory of Open Access Journals (Sweden)

    Bojjam V. Vardhini

    2015-01-01

    Full Text Available Various abiotic stress factors significantly contribute to major worldwide-losses in crop productivity by mainly impacting plant’s stress tolerance/adaptive capacity. The latter is largely governed by the efficiency of antioxidant defense system for the metabolism of elevated reactive oxygen species (ROS, caused by different abiotic stresses. Plant antioxidant defense system includes both enzymatic (such as superoxide dismutase, SOD, E.C. 1.15.1.1; catalase, CAT, E.C. 1.11.1.6; glutathione reductase, GR, E.C. 1.6.4.2; peroxidase, POD, E.C. 1.11.1.7; ascorbate peroxidase, APX, E.C. 1.11.1.11; guaiacol peroxidase, GPX, E.C. 1.11.1.7 and non-enzymatic (such as ascorbic acid, AsA; glutathione, GSH; tocopherols; phenolics, proline etc. components. Research reports on the status of various abiotic stresses and their impact on plant growth, development and productivity are extensive. However, least information is available on sustainable strategies for the mitigation of abiotic stress-mediated major consequences in plants. Brassinosteroids (BRs are a novel group of phytohormones with significant growth promoting nature. BRs are considered as growth regulators with pleiotropic effects, as they influence diverse physiological processes like growth, germination of seeds, rhizogenesis, senescence etc. and also confer abiotic stress resistance in plants. In the light of recent reports this paper: (a overviews major abiotic stresses and plant antioxidant defense system, (b introduces BRs and highlights their significance in general plant growth and development, and (c appraises recent literature available on BRs mediated modulation of various components of antioxidant defense system in plants under major abiotic stresses including metals/metalloids, drought, salinity, and temperature regimes. The outcome can be significant in devising future research in the current direction.

  10. Landrace Germplasm for Improving Yield and Abiotic Stress Adaptation.

    Science.gov (United States)

    Dwivedi, Sangam L; Ceccarelli, Salvatore; Blair, Matthew W; Upadhyaya, Hari D; Are, Ashok K; Ortiz, Rodomiro

    2016-01-01

    Plant landraces represent heterogeneous, local adaptations of domesticated species, and thereby provide genetic resources that meet current and new challenges for farming in stressful environments. These local ecotypes can show variable phenology and low-to-moderate edible yield, but are often highly nutritious. The main contributions of landraces to plant breeding have been traits for more efficient nutrient uptake and utilization, as well as useful genes for adaptation to stressful environments such as water stress, salinity, and high temperatures. We propose that a systematic landrace evaluation may define patterns of diversity, which will facilitate identifying alleles for enhancing yield and abiotic stress adaptation, thus raising the productivity and stability of staple crops in vulnerable environments.

  11. Herboxidiene triggers splicing repression and abiotic stress responses in plants

    KAUST Repository

    Alshareef, Sahar

    2017-03-27

    Background Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and stresses. Small-molecule inhibitors that perturb splicing provide invaluable tools for use as chemical probes to uncover the molecular underpinnings of splicing regulation and as potential anticancer compounds. Results Here, we show that herboxidiene (GEX1A) inhibits both constitutive and alternative splicing. Moreover, GEX1A activates genome-wide transcriptional patterns involved in abiotic stress responses in plants. GEX1A treatment -activated ABA-inducible promoters, and led to stomatal closure. Interestingly, GEX1A and pladienolide B (PB) elicited similar cellular changes, including alterations in the patterns of transcription and splicing, suggesting that these compounds might target the same spliceosome complex in plant cells. Conclusions Our study establishes GEX1A as a potent splicing inhibitor in plants that can be used to probe the assembly, dynamics, and molecular functions of the spliceosome and to study the interplay between splicing stress and abiotic stresses, as well as having potential biotechnological applications.

  12. Field evaluation of durum wheat landraces for prevailing abiotic and biotic stresses in highland rainfed regions of Iran

    Institute of Scientific and Technical Information of China (English)

    Reza; Mohammadi; Behzad; Sadeghzadeh; Hasan; Ahmadi; Nowzar; Bahrami; Ahmed; Amri

    2015-01-01

    Biotic and abiotic stresses are major limiting factors for high crop productivity worldwide. A landrace collection consisting of 380 durum wheat(Triticum turgidum L. var. durum) entries originating in several countries along with four check varieties were evaluated for biotic stresses:yellow rust(Puccinia striiformis Westendorf f. sp. tritici) and wheat stem sawfly(WSS) Cephus cinctus Norton(Hymenoptera: Cephidae), and abiotic stresses: cold and drought. The main objectives were to(i) quantify phenotypic diversity and identify variation in the durum wheat landraces for the different stresses and(ii) characterize the agronomic profiles of landraces in reaction to the stresses. Significant changes in reactions of landraces to stresses were observed.Landraces resistant to each stress were identified and agronomically characterized.Percentage reduction due to the stresses varied from 11.4%(yellow rust) to 21.6%(cold stress) for 1000-kernel weight(TKW) and from 19.9(yellow rust) to 91.9%(cold stress) for grain yield. Landraces from Asia and Europe showed enhanced genetic potential for both grain yield and cold tolerance under highland rainfed conditions of Iran. The findings showed that TKW and yield productivity could be used to assess the response of durum wheat landraces to different stresses. In conclusion, landraces showed high levels of resistance to both biotic and abiotic stresses, and selected landraces can serve in durum wheat breeding for adaptation to cold and drought-prone environments.

  13. Field evaluation of durum wheat landraces for prevailing abiotic and biotic stresses in highland rainfed regions of Iran

    Institute of Scientific and Technical Information of China (English)

    Reza Mohammadi; Behzad Sadeghzadeh; Hasan Ahmadi; Nowzar Bahrami; Ahmed Amri

    2015-01-01

    Biotic and abiotic stresses are major limiting factors for high crop productivity worldwide. A landrace collection consisting of 380 durum wheat (Triticum turgidum L. var. durum) entries originating in several countries along with four check varieties were evaluated for biotic stresses:yellow rust (Puccinia stri formis Westendorf f. sp. tritici) and wheat stem sawfly (WSS) Cephus cinctus Norton (Hymenoptera:Cephidae), and abiotic stresses:cold and drought. The main objectives were to (i) quantify phenotypic diversity and identify variation in the durum wheat landraces for the different stresses and (ii) characterize the agronomic profiles of landraces in reaction to the stresses. Significant changes in reactions of landraces to stresses were observed. Landraces resistant to each stress were identified and agronomically characterized. Percentage reduction due to the stresses varied from 11.4% (yellow rust) to 21.6% (cold stress) for 1000-kernel weight (TKW) and from 19.9 (yellow rust) to 91.9%(cold stress) for grain yield. Landraces from Asia and Europe showed enhanced genetic potential for both grain yield and cold tolerance under highland rainfed conditions of Iran. The findings showed that TKW and yield productivity could be used to assess the response of durum wheat landraces to different stresses. In conclusion, landraces showed high levels of resistance to both biotic and abiotic stresses, and selected landraces can serve in durum wheat breeding for adaptation to cold and drought-prone environments.

  14. Endophytic fungi: resource for gibberellins and crop abiotic stress resistance.

    Science.gov (United States)

    Khan, Abdul Latif; Hussain, Javid; Al-Harrasi, Ahmed; Al-Rawahi, Ahmed; Lee, In-Jung

    2015-03-01

    The beneficial effects of endophytes on plant growth are important for agricultural ecosystems because they reduce the need for fertilizers and decrease soil and water pollution while compensating for environmental perturbations. Endophytic fungi are a novel source of bioactive secondary metabolites; moreover, recently they have been found to produce physiologically active gibberellins as well. The symbiosis of gibberellins producing endophytic fungi with crops can be a promising strategy to overcome the adverse effects of abiotic stresses. The association of such endophytes has not only increased plant biomass but also ameliorated plant-growth during extreme environmental conditions. Endophytic fungi represent a trove of unexplored biodiversity and a frequently overlooked component of crop ecology. The present review describes the role of gibberellins producing endophytic fungi, suggests putative mechanisms involved in plant endophyte stress interactions and discusses future prospects in this field.

  15. Analysis of global gene expression in Brachypodium distachyon reveals extensive network plasticity in response to abiotic stress.

    Directory of Open Access Journals (Sweden)

    Henry D Priest

    Full Text Available Brachypodium distachyon is a close relative of many important cereal crops. Abiotic stress tolerance has a significant impact on productivity of agriculturally important food and feedstock crops. Analysis of the transcriptome of Brachypodium after chilling, high-salinity, drought, and heat stresses revealed diverse differential expression of many transcripts. Weighted Gene Co-Expression Network Analysis revealed 22 distinct gene modules with specific profiles of expression under each stress. Promoter analysis implicated short DNA sequences directly upstream of module members in the regulation of 21 of 22 modules. Functional analysis of module members revealed enrichment in functional terms for 10 of 22 network modules. Analysis of condition-specific correlations between differentially expressed gene pairs revealed extensive plasticity in the expression relationships of gene pairs. Photosynthesis, cell cycle, and cell wall expression modules were down-regulated by all abiotic stresses. Modules which were up-regulated by each abiotic stress fell into diverse and unique gene ontology GO categories. This study provides genomics resources and improves our understanding of abiotic stress responses of Brachypodium.

  16. Mass spectrometry-based plant metabolomics: Metabolite responses to abiotic stress.

    Science.gov (United States)

    Jorge, Tiago F; Rodrigues, João A; Caldana, Camila; Schmidt, Romy; van Dongen, Joost T; Thomas-Oates, Jane; António, Carla

    2016-09-01

    Metabolomics is one omics approach that can be used to acquire comprehensive information on the composition of a metabolite pool to provide a functional screen of the cellular state. Studies of the plant metabolome include analysis of a wide range of chemical species with diverse physical properties, from ionic inorganic compounds to biochemically derived hydrophilic carbohydrates, organic and amino acids, and a range of hydrophobic lipid-related compounds. This complexitiy brings huge challenges to the analytical technologies employed in current plant metabolomics programs, and powerful analytical tools are required for the separation and characterization of this extremely high compound diversity present in biological sample matrices. The use of mass spectrometry (MS)-based analytical platforms to profile stress-responsive metabolites that allow some plants to adapt to adverse environmental conditions is fundamental in current plant biotechnology research programs for the understanding and development of stress-tolerant plants. In this review, we describe recent applications of metabolomics and emphasize its increasing application to study plant responses to environmental (stress-) factors, including drought, salt, low oxygen caused by waterlogging or flooding of the soil, temperature, light and oxidative stress (or a combination of them). Advances in understanding the global changes occurring in plant metabolism under specific abiotic stress conditions are fundamental to enhance plant fitness and increase stress tolerance. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 35:620-649, 2016.

  17. RAP2.4a Is Transported through the Phloem to Regulate Cold and Heat Tolerance in Papaya Tree (Carica papaya cv. Maradol): Implications for Protection Against Abiotic Stress

    Science.gov (United States)

    Arroyo-Herrera, Ana; Rodriguez-Corona, Ulises; Sanchez-Teyer, Felipe; Espadas-Alcocer, Jorge; Espadas-Gil, Francisco; Barredo-Pool, Felipe; Castaño, Enrique; Rodriguez-Zapata, Luis Carlos

    2016-01-01

    Plants respond to stress through metabolic and morphological changes that increase their ability to survive and grow. To this end, several transcription factor families are responsible for transmitting the signals that are required for these changes. Here, we studied the transcription factor superfamily AP2/ERF, particularly, RAP2.4 from Carica papaya cv. Maradol. We isolated four genes (CpRap2.4a, CpRAap2.4b, CpRap2.1 and CpRap2.10), and an in silico analysis showed that the four genes encode proteins that contain a conserved APETALA2 (AP2) domain located within group I and II transcription factors of the AP2/ERF superfamily. Semiquantitative PCR experiments indicated that each CpRap2 gene is differentially expressed under stress conditions, such as extreme temperatures. Moreover, genetic transformants of tobacco plants overexpressing CpRap2.4a and CpRap2.4b genes show a high level of tolerance to cold and heat stress compared to non-transformed plants. Confocal microscopy analysis of tobacco transgenic plants showed that CpRAP2.4a and CpRAP2.4b proteins were mainly localized to the nuclei of cells from the leaves and roots and also in the sieve elements. Moreover, the movement of CpRap2.4a RNA in tobacco grafting was analyzed. Our results indicate that CpRap2.4a and CpRap2.4b RNA in the papaya tree have a functional role in the response to stress conditions such as exposure to extreme temperatures via direct translation outside the parental RNA cell. PMID:27764197

  18. Stress tolerance in plants via habitat-adapted symbiosis

    Science.gov (United States)

    Rodriguez, R.J.; Henson, J.; Van Volkenburgh, E.; Hoy, M.; Wright, L.; Beckwith, F.; Kim, Y.-O.; Redman, R.S.

    2008-01-01

    We demonstrate that native grass species from coastal and geothermal habitats require symbiotic fungal endophytes for salt and heat tolerance, respectively. Symbiotically conferred stress tolerance is a habitat-specific phenomenon with geothermal endophytes conferring heat but not salt tolerance, and coastal endophytes conferring salt but not heat tolerance. The same fungal species isolated from plants in habitats devoid of salt or heat stress did not confer these stress tolerances. Moreover, fungal endophytes from agricultural crops conferred disease resistance and not salt or heat tolerance. We define habitat-specific, symbiotically-conferred stress tolerance as habitat-adapted symbiosis and hypothesize that it is responsible for the establishment of plants in high-stress habitats. The agricultural, coastal and geothermal plant endophytes also colonized tomato (a model eudicot) and conferred disease, salt and heat tolerance, respectively. In addition, the coastal plant endophyte colonized rice (a model monocot) and conferred salt tolerance. These endophytes have a broad host range encompassing both monocots and eudicots. Interestingly, the endophytes also conferred drought tolerance to plants regardless of the habitat of origin. Abiotic stress tolerance correlated either with a decrease in water consumption or reactive oxygen sensitivity/generation but not to increased osmolyte production. The ability of fungal endophytes to confer stress tolerance to plants may provide a novel strategy for mitigating the impacts of global climate change on agricultural and native plant communities.The ISME Journal (2008) 2, 404-416; doi:10.1038/ismej.2007.106; published online 7 February 2008. ?? 2008 International Society for Microbial Ecology All rights reserved.

  19. Cowpea (Vigna unguiculata [L.] Walp.) genotypes response to multiple abiotic stresses.

    Science.gov (United States)

    Singh, Shardendu K; Kakani, Vijaya Gopal; Surabhi, Giridara-Kumar; Reddy, K Raja

    2010-09-02

    The carbon dioxide concentration [CO(2)], temperature and ultraviolet B radiation (UVB) are concomitant factors projected to change in the future environment, and their possible interactions are of significant interest to agriculture. The objectives of this study were to evaluate interactive effects of atmospheric [CO(2)], temperature, and UVB radiation on growth, physiology and reproduction of cowpea genotypes and to identify genotypic tolerance to multiple stressors. Six cowpea (Vigna unguiculata [L.] Walp.) genotypes differing in their sites of origin were grown in sunlit, controlled environment chambers. The treatments consisted of two levels each of atmospheric [CO(2)] (360 and 720 micromol mol(-1)), UVB [0 and 10 kJ m(-2)d(-1)) and temperatures [30/22 and 38/30 degrees C] from 8 days after emergence to maturity. The ameliorative effects of elevated [CO(2)] on increased UVB radiation and temperature effects were observed for most of the vegetative and photosynthetic traits but not for pollen production, pollen viability and yield attributes. The combined stress response index (C-TSRI) derived from vegetative (V-TSRI) and reproductive (R-TSRI) parameters revealed that the genotypes responded negatively with varying magnitude of responses to the stressors. Additionally, in response to multiple abiotic stresses, the vegetative traits diverged from that of reproductive traits, as deduced from the positive V-TSRI and negative R-TSRI observed in most of the genotypes and poor correlation between these two processes. The UVB in combination with increased temperature caused the greatest damage to cowpea vegetative growth and reproductive potential. The damaging effects of high temperature on seed yield was not ameliorated by elevated [CO(2)]. The identified tolerant genotypes and groups of plant attributes could be used to develop genotypes with multiple abiotic stress tolerance.

  20. Allele diversity for abiotic stress responsive candidate genes in chickpea reference set using gene based SNP markers

    Directory of Open Access Journals (Sweden)

    Manish eRoorkiwal

    2014-06-01

    Full Text Available Chickpea is an important food legume crop for the semi-arid regions, however, its productivity is adversely affected by various biotic and abiotic stresses. Identification of candidate genes associated with abiotic stress response will help breeding efforts aiming to enhance its productivity. With this objective, 10 abiotic stress responsive candidate genes were selected on the basis of prior knowledge of this complex trait. These 10 genes were subjected to allele specific sequencing across a chickpea reference set comprising 300 genotypes including 211 accessions of chickpea mini core collection. A total of 1.3 Mbp sequence data were generated. Multiple sequence alignment revealed 79 SNPs and 41 indels in nine genes while the CAP2 gene was found to be conserved across all the genotypes. Among ten candidate genes, the maximum number of SNPs (34 was observed in abscisic acid stress and ripening (ASR gene including 22 transitions, 11 transversions and one tri-allelic SNP. Nucleotide diversity varied from 0.0004 to 0.0029 while PIC values ranged from 0.01 (AKIN gene to 0.43 (CAP2 promoter. Haplotype analysis revealed that alleles were represented by more than two haplotype blocks, except alleles of the CAP2 and sucrose synthase (SuSy gene, where only one haplotype was identified. These genes can be used for association analysis and if validated, may be useful for enhancing abiotic stress, including drought tolerance, through molecular breeding.

  1. The role of transcriptional coactivator ADA2b in Arabidopsis abiotic stress responses.

    Science.gov (United States)

    Vlachonasios, Konstantinos E; Kaldis, Athanasios; Nikoloudi, Adriana; Tsementzi, Despoina

    2011-10-01

    Plant growth and crop production can be greatly affected by common environmental stresses such as drought, high salinity and low temperatures. Gene expression is affected by several abiotic stresses. Stress-inducible genes are regulated by transcription factors and epigenetic mechanisms such as histone modifications. In this Mini-Review, we have explored the role of transcriptional adaptor ADA2b in Arabidopsis responses to abiotic stress. ADA2b is required for the expression of genes involved in abiotic stress either by controlling H3 and H4 acetylation in the case of salt stress or affecting nucleosome occupancy in low temperatures response.

  2. Sugar signalling and gene expression in relation to carbohydrate metabolism under abiotic stresses in plants

    Indian Academy of Sciences (India)

    Anil K Gupta; Narinder Kaur

    2005-12-01

    Sucrose is required for plant growth and development. The sugar status of plant cells is sensed by sensor proteins. The signal generated by signal transduction cascades, which could involve mitogen-activated protein kinases, protein phosphatases, Ca2+ and calmodulins, results in appropriate gene expression. A variety of genes are either induced or repressed depending upon the status of soluble sugars. Abiotic stresses to plants result in major alterations in sugar status and hence affect the expression of various genes by down- and up-regulating their expression. Hexokinase-dependent and hexokinase-independent pathways are involved in sugar sensing. Sucrose also acts as a signal molecule as it affects the activity of a proton-sucrose symporter. The sucrose transporter acts as a sucrose sensor and is involved in phloem loading. Fructokinase may represent an additional sensor that bypasses hexokinase phosphorylation especially when sucrose synthase is dominant. Mutants isolated on the basis of response of germination and seedling growth to sugars and reporter-based screening protocols are being used to study the response of altered sugar status on gene expression. Common cis-acting elements in sugar signalling pathways have been identified. Transgenic plants with elevated levels of sugars/sugar alcohols like fructans, raffinose series oligosaccharides, trehalose and mannitol are tolerant to different stresses but have usually impaired growth. Efforts need to be made to have transgenic plants in which abiotic stress responsive genes are expressed only at the time of adverse environmental conditions instead of being constitutively synthesized.

  3. Overexpression of a cytosolic abiotic stress responsive universal stress protein (SbUSP mitigates salt and osmotic stress in transgenic tobacco plants

    Directory of Open Access Journals (Sweden)

    Pushpika eUdawat

    2016-04-01

    Full Text Available The Universal Stress Protein (USP is a ubiquitous protein and plays an indispensable role in plant abiotic stress tolerance. The genome of Salicornia brachiata contains two homologues of intron less SbUSP gene which encodes for salt and osmotic responsive universal stress protein. In vivo localization reveals that SbUSP is a membrane bound cytosolic protein. The role of the gene was functionally validated by developing transgenic tobacco and compared with control (wild type and vector control plants under different abiotic stress condition. Transgenic lines (T1 exhibited higher chlorophyll, relative water, proline, total sugar, reducing sugar, free amino acids, polyphenol contents, osmotic potential, membrane stability and lower electrolyte leakage and lipid peroxidation (malondialdehyde content under stress treatments than control (WT and VC plants. Lower accumulation of H2O2 and O2- radicals was also detected in transgenic lines compared to control plants under stress conditions. Present study confers that overexpression of the SbUSP gene enhances plant growth, alleviates ROS buildup, maintains ion homeostasis and improves the physiological status of the plant under salt and osmotic stresses. Principal component analysis (PCA exhibited a statistical distinction of plant response to salinity stress, and a significant response was observed for transgenic lines under stress, which provides stress endurance to the plant. A possible signaling role is proposed that some downstream genes may get activated by abiotic stress responsive cytosolic SbUSP, which leads to the protection of cell from oxidative damages. The study unveils that ectopic expression of the gene mitigates salt or osmotic stress by scavenging ROS and modulating the physiological process of the plant.

  4. Mechanical stress induces biotic and abiotic stress responses via a novel cis-element.

    Directory of Open Access Journals (Sweden)

    Justin W Walley

    2007-10-01

    Full Text Available Plants are continuously exposed to a myriad of abiotic and biotic stresses. However, the molecular mechanisms by which these stress signals are perceived and transduced are poorly understood. To begin to identify primary stress signal transduction components, we have focused on genes that respond rapidly (within 5 min to stress signals. Because it has been hypothesized that detection of physical stress is a mechanism common to mounting a response against a broad range of environmental stresses, we have utilized mechanical wounding as the stress stimulus and performed whole genome microarray analysis of Arabidopsis thaliana leaf tissue. This led to the identification of a number of rapid wound responsive (RWR genes. Comparison of RWR genes with published abiotic and biotic stress microarray datasets demonstrates a large overlap across a wide range of environmental stresses. Interestingly, RWR genes also exhibit a striking level and pattern of circadian regulation, with induced and repressed genes displaying antiphasic rhythms. Using bioinformatic analysis, we identified a novel motif overrepresented in the promoters of RWR genes, herein designated as the Rapid Stress Response Element (RSRE. We demonstrate in transgenic plants that multimerized RSREs are sufficient to confer a rapid response to both biotic and abiotic stresses in vivo, thereby establishing the functional involvement of this motif in primary transcriptional stress responses. Collectively, our data provide evidence for a novel cis-element that is distributed across the promoters of an array of diverse stress-responsive genes, poised to respond immediately and coordinately to stress signals. This structure suggests that plants may have a transcriptional network resembling the general stress signaling pathway in yeast and that the RSRE element may provide the key to this coordinate regulation.

  5. A Novel Aldo-Keto Reductase (AKR17A1) of Anabaena sp. PCC 7120 Degrades the Rice Field Herbicide Butachlor and Confers Tolerance to Abiotic Stresses in E. coli.

    Science.gov (United States)

    Agrawal, Chhavi; Sen, Sonia; Yadav, Shivam; Rai, Shweta; Rai, Lal Chand

    2015-01-01

    Present study deals with the identification of a novel aldo/keto reductase, AKR17A1 from Anabaena sp. PCC7120 and adds on as 17th family of AKR superfamily drawn from a wide variety of organisms. AKR17A1 shares many characteristics of a typical AKR such as- (i) conferring tolerance to multiple stresses like heat, UV-B, and cadmium, (ii) excellent activity towards known AKR substrates (isatin and 2-nitrobenzaldehyde), and (iii) obligate dependence on NADPH as a cofactor for enzyme activity. The most novel attribute of AKR17A1, first reported in this study, is its capability to metabolize butachlor, a persistent rice field herbicide that adversely affects agro-ecosystem and non-target organisms. The AKR17A1 catalyzed- degradation of butachlor resulted into formation of 1,2-benzene dicarboxylic acid and 2,6 bis (1,1, dimethylethyl) 4,-methyl phenol as the major products confirmed by GC-MS analysis.

  6. A Novel Aldo-Keto Reductase (AKR17A1 of Anabaena sp. PCC 7120 Degrades the Rice Field Herbicide Butachlor and Confers Tolerance to Abiotic Stresses in E. coli.

    Directory of Open Access Journals (Sweden)

    Chhavi Agrawal

    Full Text Available Present study deals with the identification of a novel aldo/keto reductase, AKR17A1 from Anabaena sp. PCC7120 and adds on as 17th family of AKR superfamily drawn from a wide variety of organisms. AKR17A1 shares many characteristics of a typical AKR such as- (i conferring tolerance to multiple stresses like heat, UV-B, and cadmium, (ii excellent activity towards known AKR substrates (isatin and 2-nitrobenzaldehyde, and (iii obligate dependence on NADPH as a cofactor for enzyme activity. The most novel attribute of AKR17A1, first reported in this study, is its capability to metabolize butachlor, a persistent rice field herbicide that adversely affects agro-ecosystem and non-target organisms. The AKR17A1 catalyzed- degradation of butachlor resulted into formation of 1,2-benzene dicarboxylic acid and 2,6 bis (1,1, dimethylethyl 4,-methyl phenol as the major products confirmed by GC-MS analysis.

  7. Cloning of four DREB genes from Tibetan Sophora moorcroftiana and analysis of their expression during abiotic stress

    Institute of Scientific and Technical Information of China (English)

    Weijie Yao; Yaru Fu; Yanfu Zhang; Hui-e Li

    2016-01-01

    Sophora moorcroftiana is an endemic, drought-resistant shrub that grows in Tibet and has some degree of resistance to salt, cold, heat, and drought. In the present study, four dehydration responsive element-binding (DREB) genes (SmDREB1, SmDREB2, SmDREB and SmDREB1) were isolated from S. moorcroftiana for the first time and their expression and proline content under abiotic stress were analyzed. Proline accumulated in seedlings under drought, salt, cold, and heat stress treat-ments. The four genes were variously expressed in response to the four abiotic stresses. SmDREB1 was induced by drought, cold, and heat stresses;SmDREB2 and SmDREB4 were both induced by salt, cold, and heat stresses, whereas SmDREB3 was induced by drought and heat stresses. Thus, these four genes may participate in conferring tolerance to these four abiotic stresses and are candidate genes for genetic engineering in the future.

  8. Calcium-Dependent Protein Kinase CPK21 Functions in Abiotic Stress Response in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Sandra Franz; Britta Ehlert; Anja Liese; Joachim Kurth; Anne-Claire Cazalé; Tina Romeis

    2011-01-01

    Calcium-dependent protein kinases(CDPKs)comprise a family of plant serine/threonine protein kinases in which the calcium sensing domain and the kinase effector domain are combined within one molecule.So far,a biological function in abiotic stress signaling has only been reported for few CDPK isoforms,whereas the underlying biochemical mechanism for these CDPKs is still mainly unknown.Here,we show that CPK21 from Arabidopsis thaliana is biochemically activated in vivo in response to hyperosmotic stress.Loss-of-function seedlings of cpk21 are more tolerant to hyperosmotic stress and mutant plants show increased stress responses with respect to marker gene expression and metabolite accumulation.In transgenic Arabidopsis complementation lines in the cpk21 mutant background,in which either CPK21 wildtype,or a full-length enzyme variant carrying an amino-acid substitution were stably expressed,stress responsitivity was restored by CPK21 but not with the kinase inactive variant.The biochemical characterization of in planta synthesized and purified CPK21 protein revealed that within the calcium-binding domain,N-terminal EF1- and EF2-motifs compared to C-terminal EF3- and EF4-motifs differ in their contribution to calcium-regulated kinase activity,suggesting a crucial role for the N-terminal EF-hand pair.Our data provide evidence for CPK21 contributing in abiotic stress signaling and suggest that the N-terminal EF-hand pair is a calcium-sensing determinant controlling specificity of CPK21 function.

  9. Polyamines Function in Stress Tolerance: From Synthesis to Regulation

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    Ji-Hong eLiu

    2015-10-01

    Full Text Available Plants are challenged by a variety of biotic or abiotic stresses, which can affect their growth and development, productivity and geographic distribution. In order to survive adverse environmental conditions, plants have evolved various adaptive strategies, among which is the accumulation of metabolites that play protective roles. A well-established example of the metabolites that are involved in stress responses, or stress tolerance, is the low-molecular-weight aliphatic polyamines, including putrescine,spermidine and spermine. The critical role of polyamines in stress tolerance is suggested by several lines of evidence: firstly, the transcript levels of polyamine biosynthetic genes, as well as the activities of the corresponding enzymes, are induced by stresses; secondly, elevation of endogenous polyamine levels by exogenous supply of polyamines, or overexpression of polyamine biosynthetic genes, results in enhanced stress tolerance; and thirdly, a reduction of endogenous polyamines is accompanied by compromised stress tolerance. A number of studies have demonstrated that polyamines function in stress tolerance largely by modulating the homeostasis of reactive oxygen species (ROS due to their direct, or indirect, roles in regulating antioxidant systems or suppressing ROS production. The transcriptional regulation of polyamine synthesis by transcription factors is also reviewed here. Meanwhile, future perspectives on polyamine research are also suggested.

  10. Biotic and abiotic stress can induce cystatin expression in chestnut.

    Science.gov (United States)

    Pernas, M; Sánchez-Monge, R; Salcedo, G

    2000-02-11

    A cysteine proteinase inhibitor (cystatin) from chestnut (Castanea sativa) seeds, designated CsC, has been previously characterized. Its antifungal, acaricide and inhibitory activities have allowed to involve CsC in defence mechanisms. The CsC transcription levels decreased during seed maturation and increased throughout germination, an opposite behavior to that shown by most phytocystatins. No inhibition of endogenous proteinase activity by purified CsC was found during the seed maturation or germination processes. CsC message accumulation was induced in chestnut leaves after fungal infection, as well as by wounding and jasmonic acid treatment. Induction in roots was also observed by the last two treatments. Furthermore, CsC transcript levels strongly raised, both in roots and leaves, when chestnut plantlets were subjected to cold- and saline-shocks, and also in roots by heat stress. All together, these data suggest that chestnut cystatin is not only involved in defence responses to pests and pathogen invasion, but also in those related to abiotic stress.

  11. Verification of the resistance of a LEA gene from Tamarix expression in Saccharomyces cerevisiae to abiotic stresses

    Institute of Scientific and Technical Information of China (English)

    WANG Bing-feng; WANG Yu-cheng; ZHANG Da-wei; LI Hong-yan; YANG Chuan-ping

    2008-01-01

    The role of late embryogenesis abundant (LEA) proteins in stress tolerance was examined by using a yeast expression system. LEA protein tolerance to the abotic stresses in plants involved in salt, drought and freezing stresses and additional tolerance to heat, NaHCO3 (salt-alkali) and ultraviolet radiation was also investigated. The transgenic yeast harboring the Tamarix LEA gene (DQ663481) was generated under the control of inducible GAL promoter (pYES2 vector), yeast cells transformed with pYES2 empty vector were also generated as a control. Stress tolerance tests showed that LEA yeast transformants exhibited a higher survival rates than the control transformants under high temperature, NaHCO3, ultraviolet radiation, salt (NaCl), drought and freezing, indicating that the LEA gene is tolerant to these abiotic stresses. These results suggest that the LEA gene is resistant to a wider repertoire of stresses and may play a common role in plant acclimation to the examined stress conditions.

  12. The transcriptional regulatory network in the drought response and its crosstalk in abiotic stress responses including drought, cold and heat

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    Kazuo eNakashima

    2014-05-01

    Full Text Available Drought negatively impacts plant growth and the productivity of crops around the world. Understanding the molecular mechanisms in the drought response is important for improvement of drought tolerance using molecular techniques. In plants, abscisic acid (ABA is accumulated under osmotic stress conditions caused by drought, and has a key role in stress responses and tolerance. Comprehensive molecular analyses have shown that ABA regulates the expression of many genes under osmotic stress conditions, and the ABA-responsive element (ABRE is the major cis-element for ABA-responsive gene expression. Transcription factors (TFs are master regulators of gene expression. ABRE-binding protein (AREB and ABRE-binding factor (ABF TFs control gene expression in an ABA-dependent manner. SNF1-related protein kinases 2, group A 2C-type protein phosphatases, and ABA receptors were shown to control the ABA signaling pathway. ABA-independent signaling pathways such as dehydration-responsive element-binding protein (DREB TFs and NAC TFs are also involved in stress responses including drought, heat and cold. Recent studies have suggested that there are interactions between the major ABA signaling pathway and other signaling factors in stress responses. The important roles of these transcription factors in crosstalk among abiotic stress responses will be discussed. Control of ABA or stress signaling factor expression can improve tolerance to environmental stresses. Recent studies using crops have shown that stress-specific overexpression of TFs improves drought tolerance and grain yield compared with controls in the field.

  13. Isolation and characterization of a catalase gene "HuCAT3" from pitaya (Hylocereus undatus) and its expression under abiotic stress.

    Science.gov (United States)

    Nie, Qiong; Gao, Guo-Li; Fan, Qing-jie; Qiao, Guang; Wen, Xiao-Peng; Liu, Tao; Peng, Zhi-Jun; Cai, Yong-Qiang

    2015-05-25

    Abiotic stresses usually cause H2O2 accumulation, with harmful effects, in plants. Catalase may play a key protective role in plant cells by detoxifying this excess H2O2. Pitaya (Hylocereus undatus) shows broad ecological adaptation due to its high tolerance to abiotic stresses, e.g. drought, heat and poor soil. However, involvement of the pitaya catalase gene (HuCAT) in tolerance to abiotic stresses is unknown. In the present study, a full-length HuCAT3 cDNA (1870 bp) was isolated from pitaya based on our previous microarray data and RACE method. The cDNA sequence and deduced amino acid sequence shared 73-77% and 75-80% identity with other plant catalases, respectively. HuCAT3 contains conserved catalase family domain and catalytic sites. Pairwise comparison and phylogenetic analysis indicated that HuCAT3 is most similar to Eriobotrya japonica CAT, followed by Dimocarpus longan CAT and Nicotiana tabacum CAT1. Expression profile analysis demonstrated that HuCAT3 is mainly expressed in green cotyledons and mature stems, and was regulated by H2O2, drought, cold and salt stress, whereas, its expression patterns and maximum expression levels varied with stress types. HuCAT activity increased as exposure to the tested stresses, and the fluctuation of HuCAT activity was consistent with HuCAT3 mRNA abundance (except for 0.5 days upon drought stress). HuCAT3 mRNA elevations and HuCAT activities changes under cold stress were also in conformity with the cold tolerances among the four genotypes. The obtained results confirmed a major role of HuCAT3 in abiotic stress response of pitaya. This may prove useful in understanding pitaya's high tolerance to abiotic stresses at molecular level.

  14. Speculation: Polyamines are important in abiotic stress signaling.

    Science.gov (United States)

    Pál, Magda; Szalai, Gabriella; Janda, Tibor

    2015-08-01

    The main role of polyamines was originally assumed to be as direct protective compounds important under stress conditions. Although in some cases a correlation was found between the endogenous polyamine content and stress tolerance, this relationship cannot be generalized. Polyamines should no longer be considered simply as protective molecules, but rather as compounds that are involved in a complex signaling system and have a key role in the regulation of stress tolerance. The major links in polyamine signaling may be H2O2 and NO, which are not only produced in the course of the polyamine metabolism, but also transmit signals that influence gene expression via an increase in the cytoplasmic Ca(2+) level. Polyamines can also influence Ca(2+) influx independently of the H2O2- and/or NO-mediated pathways. Furthermore, these pathways may converge. In addition, several protein kinases have been shown to be influenced at the transcriptional or post-translational level by polyamines. Individual polyamines can be converted into each other in the polyamine cycle. In addition, their metabolism is linked with other hormones or signaling molecules. However, as individual polyamines trigger different transcriptional responses, other mechanisms and the existence of polyamine-responsive elements and the corresponding transacting protein factors are also involved in polyamine-related signaling pathways.

  15. New Approaches for Crop Genetic Adaptation to the Abiotic Stresses Predicted with Climate Change

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    Robert Redden

    2013-05-01

    Full Text Available Extreme climatic variation is predicted with climate change this century. In many cropping regions, the crop environment will tend to be warmer with more irregular rainfall and spikes in stress levels will be more severe. The challenge is not only to raise agricultural production for an expanding population, but to achieve this under more adverse environmental conditions. It is now possible to systematically explore the genetic variation in historic local landraces by using GPS locators and world climate maps to describe the natural selection for local adaptation, and to identify candidate germplasm for tolerances to extreme stresses. The physiological and biochemical components of these expressions can be genomically investigated with candidate gene approaches and next generation sequencing. Wild relatives of crops have largely untapped genetic variation for abiotic and biotic stress tolerances, and could greatly expand the available domesticated gene pools to assist crops to survive in the predicted extremes of climate change, a survivalomics strategy. Genomic strategies can assist in the introgression of these valuable traits into the domesticated crop gene pools, where they can be better evaluated for crop improvement. The challenge is to increase agricultural productivity despite climate change. This calls for the integration of many disciplines from eco-geographical analyses of genetic resources to new advances in genomics, agronomy and farm management, underpinned by an understanding of how crop adaptation to climate is affected by genotype × environment interaction.

  16. Transcriptional profiling of Medicago truncatula under salt stress identified a novel CBF transcription factor MtCBF4 that plays an important role in abiotic stress responses

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    Su Zhen

    2011-07-01

    Full Text Available Abstract Background Salt stress hinders the growth of plants and reduces crop production worldwide. However, different plant species might possess different adaptive mechanisms to mitigate salt stress. We conducted a detailed pathway analysis of transcriptional dynamics in the roots of Medicago truncatula seedlings under salt stress and selected a transcription factor gene, MtCBF4, for experimental validation. Results A microarray experiment was conducted using root samples collected 6, 24, and 48 h after application of 180 mM NaCl. Analysis of 11 statistically significant expression profiles revealed different behaviors between primary and secondary metabolism pathways in response to external stress. Secondary metabolism that helps to maintain osmotic balance was induced. One of the highly induced transcription factor genes was successfully cloned, and was named MtCBF4. Phylogenetic analysis revealed that MtCBF4, which belongs to the AP2-EREBP transcription factor family, is a novel member of the CBF transcription factor in M. truncatula. MtCBF4 is shown to be a nuclear-localized protein. Expression of MtCBF4 in M. truncatula was induced by most of the abiotic stresses, including salt, drought, cold, and abscisic acid, suggesting crosstalk between these abiotic stresses. Transgenic Arabidopsis over-expressing MtCBF4 enhanced tolerance to drought and salt stress, and activated expression of downstream genes that contain DRE elements. Over-expression of MtCBF4 in M. truncatula also enhanced salt tolerance and induced expression level of corresponding downstream genes. Conclusion Comprehensive transcriptomic analysis revealed complex mechanisms exist in plants in response to salt stress. The novel transcription factor gene MtCBF4 identified here played an important role in response to abiotic stresses, indicating that it might be a good candidate gene for genetic improvement to produce stress-tolerant plants.

  17. Hydrogen peroxide and polyamines act as double edged swords in plant abiotic stress responses

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    Kamala Gupta

    2016-09-01

    Full Text Available The specific genetic changes through which plants adapt to the multitude of environmental stresses are possible because of the molecular regulations in the system. These intricate regulatory mechanisms once unveiled will surely raise interesting questions. Polyamines and hydrogen peroxide have been suggested to be important signalling molecules during biotic and abiotic stresses. Hydrogen peroxide plays a versatile role from orchestrating physiological processes to stress response. It helps to achieve acclimatization and tolerance to stress by coordinating intra-cellular and systemic signalling systems. Polyamines, on the other hand, are low molecular weight polycationic aliphatic amines, which have been implicated in various stress responses. It is quite interesting to note that both hydrogen peroxide and polyamines have a fine line of inter-relation between them since the catabolic pathways of the latter releases hydrogen peroxide. In this review we have tried to illustrate the roles and their multifaceted functions of these two important signalling molecules based on current literature. This review also highlights the fact that over accumulation of hydrogen peroxide and polyamines can be detrimental for plant cells leading to toxicity and pre-mature cell death.

  18. Impact of abiotic stress on photosynthetic efficiency and leaf temperature in sunflower

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    Antonela Markulj Kulundžić

    2016-11-01

    Full Text Available The aim of this research was to investigate the variability of photosynthetic performance index (PIABS and leaf temperature values measured in V6 development phase on 13 sunflower hybrids, grown in stressful conditions. The pot trial was made up of two treatments, one (T1 with 60% Field Water Capacity (FWC, and the other one (T2 with 80% FWC. Significant differences between T1 and T2 treatments were established for both of these parameters which prove their dependence on the water content in the soil, while the influence of hybrid was evident only in the case of PIABS. Although in T1, as opposed to T2, all sunflower hybrids reacted by increasing leaf temperature, reaction to stress conditions measured with PIABS parameter was not uniform. Some of the hybrids reacted by decreasing PIABS values, while others reacted by increasing their PIABS values. Therefore, it can be concluded that changes in parameters were independent of each other, which was confirmed by correlation analysis. Investigated parameters are suitable for determining the existence of undesirable environmental conditions that cause stress in plants and can be used in breeding of sunflower to withstand abiotic stress conditions, i.e. in selection of stress tolerant hybrids.

  19. Transcriptome-Based Analysis of Dof Family Transcription Factors and Their Responses to Abiotic Stress in Tea Plant (Camellia sinensis

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    Hui Li

    2016-01-01

    Full Text Available Tea plant (Camellia sinensis (L. O. Kuntze is affected by abiotic stress during its growth and development. DNA-binding with one finger (Dof transcription factors (TFs play important roles in abiotic stress tolerance of plants. In this study, a total of 29 putative Dof TFs were identified based on transcriptome of tea plant, and the conserved domains and common motifs of these CsDof TFs were predicted and analyzed. The 29 CsDof proteins were divided into 7 groups (A, B1, B2, C1, C2.1, C2.2, and D2, and the interaction networks of Dof proteins in C. sinensis were established according to the data in Arabidopsis. Gene expression was analyzed in “Yingshuang” and “Huangjinya” under four experimental stresses by qRT-PCR. CsDof genes were expressed differentially and related to different abiotic stress conditions. In total, our results might suggest that there is a potential relationship between CsDof factors and tea plant stress resistance.

  20. Trichoderma genes in plants for stress tolerance- status and prospects.

    Science.gov (United States)

    Nicolás, Carlos; Hermosa, Rosa; Rubio, Belén; Mukherjee, Prasun K; Monte, Enrique

    2014-11-01

    Many filamentous fungi from the genus Trichoderma are well known for their anti-microbial properties. Certain genes from Trichoderma spp. have been identified and transferred to plants for improving biotic and abiotic stress tolerance, as well for applications in bioremediation. Several Trichoderma genomes have been sequenced and many are in the pipeline, facilitating high throughput gene analysis and increasing the availability of candidate transgenes. This, coupled with improved plant transformation systems, is expected to usher in a new era in plant biotechnology where several genes from these antagonistic fungi can be transferred into plants to achieve enhanced stress tolerance, bioremediation activity, herbicide tolerance, and reduction of phytotoxins. In this review, we illustrate the major achievements made by transforming plants with Trichoderma genes as well as their possible mode of action. Moreover, examples of efficient application of genetically modified plants as biofactories to produce active Trichoderma enzymes are indicated.

  1. Association genetics and expression patterns of a CBF4 homolog in Populus under abiotic stress.

    Science.gov (United States)

    Li, Ying; Xu, Baohua; Du, Qingzhang; Zhang, Deqiang

    2015-06-01

    New strategies for prevention and treatment of abiotic stress require an improved understanding of stress responses. Here, we examined response differences of a C-repeat binding factor gene (PsCBF4) between five species in the genus Populus. We also used a candidate gene-based approach to identify single nucleotide polymorphisms (SNPs) within PsCBF4 that were associated with physiological and biochemical traits in a natural population (528 unrelated individuals) of Populus simonii. We first isolated a 1,044-bp PsCBF4 cDNA encoding a polypeptide of 256 amino acids. Expression profiling revealed that CBF4 is differentially expressed under cold, heat, drought, and salt conditions among five Populus species. Cold stress is the most significant interspecific difference, and PsCBF4 transcript levels ranged from 6.5 to 379.5 times higher than in unstressed controls. A natural population of P. simonii showed high nucleotide diversity (π T = 0.00880, θ w = 0.01192) and low linkage disequilibrium (r (2) ≥ 0.1, within 700 bp) across PsCBF4. Association analysis showed that nine SNPs (false discovery rate Q stress tolerance in P. simonii.

  2. Induction of systemic stress tolerance by brassinosteroid in Cucumis sativus.

    Science.gov (United States)

    Xia, Xiao-Jian; Zhou, Yan-Hong; Ding, Ju; Shi, Kai; Asami, Tadao; Chen, Zhixiang; Yu, Jing-Quan

    2011-08-01

    • Brassinosteroids (BRs) are a new class of plant hormones that are essential for plant growth and development. Here, the involvement of BRs in plant systemic tolerance to biotic and abiotic stresses was studied. • The effects of 24-epibrassinolide (EBR) on plant stress tolerance were studied through the assessment of symptoms of photooxidative stress by chlorophyll fluorescence imaging pulse amplitude modulation, the analysis of gene expression using quantitative real-time PCR and the measurement of hydrogen peroxide (H₂O₂) production using a spectrophotometric assay or confocal laser scanning microscopy. • Treatment of primary leaves with EBR induced systemic tolerance to photooxidative stress in untreated upper and lower leaves. This was accompanied by the systemic accumulation of H₂O₂ and the systemic induction of genes associated with stress responses. Foliar treatment of EBR also enhanced root resistance to Fusarium wilt pathogen. Pharmacological study showed that EBR-induced systemic tolerance was dependent on local and systemic H₂O₂ accumulation. The expression of BR biosynthetic genes was repressed in EBR-treated leaves, but elevated significantly in untreated systemic leaves. Further analysis indicated that EBR-induced systemic induction of BR biosynthetic genes was mediated by systemically elevated H₂O₂. • These results strongly argue that local EBR treatment can activate the continuous production of H₂O₂, and the autopropagative nature of the reactive oxygen species signal, in turn, mediates EBR-induced systemic tolerance.

  3. Ethylene is involved in brassinosteroids induced alternative respiratory pathway in cucumber (Cucumis sativus L. seedlings response to abiotic stress

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    Lijie eWei

    2015-11-01

    Full Text Available Effects of brassinosteroids (BRs on cucumber (Cucumis sativus L. abiotic stresses resistance to salt, polyethylene glycol (PEG, cold and the potential mechanisms were investigated in this work. Previous reports have indicated that BRs can induce ethylene production and enhance alternative oxidase (AOX pathway. The mechanisms whether ethylene is involved as a signal molecule which connected BR with AOX in regulating stress tolerance are still unknown. Here, we found that pretreatment with 1 µM brassinolide (BL, the most active BRs relieved stress-caused oxidative damage in cucumber seedlings and clearly enhanced the capacity of AOX and the ethylene biosynthesis. Furthermore, transcription level of ethylene signaling biosynthesis genes including ripening-related ACC synthase1 (CSACS1, ripening-related ACC synthase2 (CSACS2, ripening-related ACC synthase3 (CSACS3, 1-aminocyclopropane-1-carboxylate oxidase1 (CSACO1, 1-aminocyclopropane-1-carboxylate oxidase2 (CSACO2 and CSAOX were increased after BL treatment. Importantly, the application of the salicylhydroxamic acid (SHAM, AOX inhibitor and ethylene biosynthesis inhibitor aminooxyacetic acid (AOA decreased plant resistance to environmental stress by blocking BRs-induced alternative respiration. Taken together, our results demonstrated that ethylene was involved in BRs-induced AOX activity which played important roles in abiotic stresses tolerance in cucumber seedlings.

  4. Differential responses of three sweetpotato metallothionein genes to abiotic stress and heavy metals.

    Science.gov (United States)

    Kim, Sun Ha; Jeong, Jae Cheol; Ahn, Young Ock; Lee, Haeng-Soon; Kwak, Sang-Soo

    2014-10-01

    Metallothioneins (MTs) are cysteine-rich, low molecular weight, metal-binding proteins that are widely distributed in living organisms. Plants produce metal-chelating proteins such as MTs to overcome the toxic effects of heavy metals. We cloned three MT genes from sweetpotato leaves [Ipomoea batatas (L.) Lam.]. The three IbMT genes were classified according to their cysteine residue alignment into type 1 (IbMT1), type 2 (IbMT2), and type 3 (IbMT3). IbMT1 was the most abundantly transcribed MT. It was predominantly expressed in leaves, roots, and callus. IbMT2 transcript was detected only in stems and fibrous roots, whereas IbMT3 was strongly expressed in leaves and stems. The IbMT expression profiles were investigated in plants exposed to heavy metals and abiotic stresses. The levels of IbMT1 expression were strongly elevated in response to Cd and Fe, and moderately higher in response to Cu. The IbMT3 expression pattern in response to heavy metals was similar to that of IbMT1. Exposure to abiotic stresses such as methyl viologen (MV; paraquat), NaCl, polyethylene glycol (PEG), and H2O2 up-regulated IbMT expression; IbMT1 responded strongly to MV and NaCl, whereas IbMT3 was induced by low temperature and PEG. Transgenic Escherichia coli overexpressing IbMT1 protein exhibited results suggest that IbMT could be a useful tool for engineering plants with enhanced tolerance to environmental stresses and heavy metals.

  5. Using the Model Perennial Grass Brachypodium sylvaticum to Engineer Resistance to Multiple Abiotic Stresses

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, Sean; Reguera, Maria; Sade, Nir; Cartwright, Amy; Tobias, Christian; Thilmony, Roger; Blumwald, Eduardo; Vogel, John

    2015-03-20

    We are using the perennial model grass Brachypodium sylvaticum to identify combinations of transgenes that enhance tolerance to multiple, simultaneous abiotic stresses. The most successful transgene combinations will ultimately be used to create improved switchgrass (Panicum virgatum L.) cultivars. To further develop B. sylvaticum as a perennial model grass, and facilitate our planned transcriptional profiling, we are sequencing and annotating the genome. We have generated ~40x genome coverage using PacBio sequencing of the largest possible size selected libraries (18, 22, 25 kb). Our initial assembly using only long-read sequence contained 320 Mb of sequence with an N50 contig length of 315 kb and an N95 contig length of 40 kb. This assembly consists of 2,430 contigs, the largest of which was 1.6 Mb. The estimated genome size based on c-values is 340 Mb indicating that about 20 Mb of presumably repetitive DNA remains yet unassembled. Significantly, this assembly is far superior to an assembly created from paired-end short-read sequence, ~100x genome coverage. The short-read-only assembly contained only 226 Mb of sequence in 19k contigs. To aid the assembly of the scaffolds into chromosome-scale assemblies we produced an F2 mapping population and have genotyped 480 individuals using a genotype by sequence approach. One of the reasons for using B. sylvaticum as a model system is to determine if the transgenes adversely affect perenniality and winter hardiness. Toward this goal, we examined the freezing tolerance of wild type B. sylvaticum lines to determine the optimal conditions for testing the freezing tolerance of the transgenics. A survey of seven accessions noted significant natural variation in freezing tolerance. Seedling or adult Ain-1 plants, the line used for transformation, survived an 8 hour challenge down to -6 oC and 50% survived a challenge down to -9 oC. Thus, we will be able to easily determine if the transgenes compromise freezing tolerance. In the

  6. ANTHOCYANIN PIGMENTATION IN TRITICUM AESTIVUM L.: GENETIC BASIS AND ROLE UNDER ABIOTIC STRESS CONDITIONS

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    Tereshchenko O.Yu.

    2012-08-01

    Full Text Available Anthocyanins are secondary metabolites of plants. They have a wide range of biological activity such as antioxidant, photoprotection, osmoregulation, heavy metal ions chelation, antimicrobial and antifungal activities, which help plants to survive under different stress conditions. Bread wheat (T. aestivum L. can have purple pigmentation provided by anthocyanin compounds in different organs, such as grain pericarp, coleoptile, culm, leaf blades, leaf sheaths, glumes and anthers. However, the genetic mechanisms underlying formation of these traits as well as contribution of the pigmentation to stress tolerance have not been widely studied in wheat. The aim of the current study was to investigate molecular-genetic mechanisms underlying anthocyanin pigmentation in different wheat organs and to estimate the role of the pigmentation under different abiotic stress conditions in wheat seedlings. In the current study, near-isogenic lines (NILs: cv. ‘Saratovskaya 29’ (‘S29’ and lines i:S29Pp1Pp2PF and i:S29Pp1Pp3P developed on the ‘S29’ background but having grain pericarp coloration (genes Pp and more intense coleoptile (Rc, culm (Pc, leaf blade (Plb, leaf sheath (Pls pigmentation in comparison with ‘S29’, were used. Comparative transcriptional analysis of the five structural genes Chs, Chi, F3h, Dfr, Ans, encoding enzymes participating in the anthocyanin biosynthesis, was performed in different organs of NILs. It was shown that the presence of the Rc, Pc, Plb, Pls and Pp alleles conferring strong anthocyanin pigmentation induced more intense transcription of the structural genes, suggesting the genes Rc, Pc, Plb, Pls and Pp to play a regulatory role in anthocyanin biosynthesis network. To evaluate the role of anthocyanins in stress response at the seedling stage, growth ability of the NILs and anthocyanin content in their coleoptiles were assessed after treatments with NaCl (100 and 200 mM, CdCl2 (25 and 50 μM and 15% PEG 6000

  7. Influence of combined biotic and abiotic stress on nutritional quality parameters in tomato (Solanum lycopersicum).

    Science.gov (United States)

    Atkinson, Nicky J; Dew, Tristan P; Orfila, Caroline; Urwin, Peter E

    2011-09-14

    Induction of abiotic stress in tomato plants has been proposed as a mechanism for improving the nutritional quality of fruits. However, the occurrence of biotic stress can interfere with normal abiotic stress responses. In this study, the combined effect of water stress and infection with plant-parasitic nematodes on the nutritional quality of tomato was investigated. Plants were exposed to one or both stresses, and the levels of phenolic compounds, carotenoids, and sugars in fruits were analyzed as well as physiological responses. Levels of carotenoids lycopene and β-carotene were lower in water-stressed tomatoes but exhibited a different response pattern under combined stress. Nematode stress was associated with increased flavonoid levels, albeit with reduced yields, while chlorogenic acid was increased by nematodes, water stress, and the combined stress. Sugar levels were higher only in tomatoes exposed to both stresses. These results emphasize the importance of studying plant stress factors in combination.

  8. Identification of Arabidopsis candidate genes in response to biotic and abiotic stresses using comparative microarrays.

    Directory of Open Access Journals (Sweden)

    Arjun Sham

    Full Text Available Plants have evolved with intricate mechanisms to cope with multiple environmental stresses. To adapt with biotic and abiotic stresses, plant responses involve changes at the cellular and molecular levels. The current study was designed to investigate the effects of combinations of different environmental stresses on the transcriptome level of Arabidopsis genome using public microarray databases. We investigated the role of cyclopentenones in mediating plant responses to environmental stress through TGA (TGACG motif-binding factor transcription factor, independently from jasmonic acid. Candidate genes were identified by comparing plants inoculated with Botrytis cinerea or treated with heat, salt or osmotic stress with non-inoculated or non-treated tissues. About 2.5% heat-, 19% salinity- and 41% osmotic stress-induced genes were commonly upregulated by B. cinerea-treatment; and 7.6%, 19% and 48% of genes were commonly downregulated by B. cinerea-treatment, respectively. Our results indicate that plant responses to biotic and abiotic stresses are mediated by several common regulatory genes. Comparisons between transcriptome data from Arabidopsis stressed-plants support our hypothesis that some molecular and biological processes involved in biotic and abiotic stress response are conserved. Thirteen of the common regulated genes to abiotic and biotic stresses were studied in detail to determine their role in plant resistance to B. cinerea. Moreover, a T-DNA insertion mutant of the Responsive to Dehydration gene (rd20, encoding for a member of the caleosin (lipid surface protein family, showed an enhanced sensitivity to B. cinerea infection and drought. Overall, the overlapping of plant responses to abiotic and biotic stresses, coupled with the sensitivity of the rd20 mutant, may provide new interesting programs for increased plant resistance to multiple environmental stresses, and ultimately increases its chances to survive. Future research

  9. ABIOTIC STRESS RESISTANCE IN YOUNG APPLE TREES IS ENHANCED BY OVEREXPRESSION OF A CYTOSOLIC SUPEROXIDE DISMUTASE

    Science.gov (United States)

    Reactive oxygen species (ROS) are induced during both biotic and abiotic stress, either as signaling molecules or as a response to stress injury. ROS are highly destructive to cell components and the injury resulting from these compounds is referred to as oxidative stress. Antioxidant enzymes, suc...

  10. Genome-wide identification, expression analysis of auxin-responsive GH3 family genes in maize (Zea mays L.) under abiotic stresses.

    Science.gov (United States)

    Feng, Shangguo; Yue, Runqing; Tao, Sun; Yang, Yanjun; Zhang, Lei; Xu, Mingfeng; Wang, Huizhong; Shen, Chenjia

    2015-09-01

    Auxin is involved in different aspects of plant growth and development by regulating the expression of auxin-responsive family genes. As one of the three major auxin-responsive families, GH3 (Gretchen Hagen3) genes participate in auxin homeostasis by catalyzing auxin conjugation and bounding free indole-3-acetic acid (IAA) to amino acids. However, how GH3 genes function in responses to abiotic stresses and various hormones in maize is largely unknown. Here, the latest updated maize (Zea mays L.) reference genome sequence was used to characterize and analyze the ZmGH3 family genes from maize. The results showed that 13 ZmGH3 genes were mapped on five maize chromosomes (total 10 chromosomes). Highly diversified gene structures and tissue-specific expression patterns suggested the possibility of function diversification for these genes in response to environmental stresses and hormone stimuli. The expression patterns of ZmGH3 genes are responsive to several abiotic stresses (salt, drought and cadmium) and major stress-related hormones (abscisic acid, salicylic acid and jasmonic acid). Various environmental factors suppress auxin free IAA contents in maize roots suggesting that these abiotic stresses and hormones might alter GH3-mediated auxin levels. The responsiveness of ZmGH3 genes to a wide range of abiotic stresses and stress-related hormones suggested that ZmGH3s are involved in maize tolerance to environmental stresses.

  11. Genome-wide identification, expression analysis of auxin-responsive GH3 family genes in maize (Zea mays L.) under abiotic stresses

    Institute of Scientific and Technical Information of China (English)

    Shangguo Feng; Runqing Yue; Sun Tao Yanjun Yang; Lei Zhang; Mingfeng Xu; Huizhong Wang; Chenjia Shen

    2015-01-01

    Auxin is involved in different aspects of plant growth and development by regulating the expression of auxin-responsive family genes. As one of the three major auxin-responsive families, GH3 (Gretchen Hagen3) genes participate in auxin homeostasis by catalyzing auxin conjugation and bounding free indole-3-acetic acid (IAA) to amino acids. However, how GH3 genes function in responses to abiotic stresses and various hormones in maize is largely unknown. Here, the latest updated maize (Zea mays L.) reference genome sequence was used to characterize and analyze the ZmGH3 family genes from maize. The results showed that 13 ZmGH3 genes were mapped on five maize chromosomes (total 10 chromosomes). Highly diversified gene structures and tissue-specific expression patterns suggested the possibility of function diversification for these genes in response to environmental stresses and hormone stimuli. The expression patterns of ZmGH3 genes are responsive to several abiotic stresses (salt, drought and cadmium) and major stress-related hormones (abscisic acid, salicylic acid and jasmonic acid). Various environmental factors suppress auxin free IAA contents in maize roots suggesting that these abiotic stresses and hormones might alter GH3-mediated auxin levels. The respon-siveness of ZmGH3 genes to a wide range of abiotic stresses and stress-related hormones suggested that ZmGH3s are involved in maize tolerance to environmental stresses.

  12. The WRKY transcription factors in the diploid woodland strawberry Fragaria vesca: Identification and expression analysis under biotic and abiotic stresses.

    Science.gov (United States)

    Wei, Wei; Hu, Yang; Han, Yong-Tao; Zhang, Kai; Zhao, Feng-Li; Feng, Jia-Yue

    2016-08-01

    WRKY proteins comprise a large family of transcription factors that play important roles in response to biotic and abiotic stresses and in plant growth and development. To date, little is known about the WRKY gene family in strawberry. In this study, we identified 62 WRKY genes (FvWRKYs) in the wild diploid woodland strawberry (Fragaria vesca, 2n = 2x = 14) accession Heilongjiang-3. According to the phylogenetic analysis and structural features, these identified strawberry FvWRKY genes were classified into three main groups. In addition, eight FvWRKY-GFP fusion proteins showed distinct subcellular localizations in Arabidopsis mesophyll protoplasts. Furthermore, we examined the expression of the 62 FvWRKY genes in 'Heilongjiang-3' under various conditions, including biotic stress (Podosphaera aphanis), abiotic stresses (drought, salt, cold, and heat), and hormone treatments (abscisic acid, ethephon, methyl jasmonate, and salicylic acid). The expression levels of 33 FvWRKY genes were upregulated, while 12 FvWRKY genes were downregulated during powdery mildew infection. FvWRKY genes responded to drought and salt treatment to a greater extent than to temperature stress. Expression profiles derived from quantitative real-time PCR suggested that 11 FvWRKY genes responded dramatically to various stimuli at the transcriptional level, indicating versatile roles in responses to biotic and abiotic stresses. Interaction networks revealed that the crucial pathways controlled by WRKY proteins may be involved in the differential response to biotic stress. Taken together, the present work may provide the basis for future studies of the genetic modification of WRKY genes for pathogen resistance and stress tolerance in strawberry.

  13. Adaptation and survival of plants in high stress habitats via fungal endophyte conferred stress tolerance

    Science.gov (United States)

    Rodriguez, Rusty J.; Woodward, Claire; Redman, Regina S.

    2010-01-01

    From the Arctic to the Antarctic, plants thrive in diverse habitats that impose different levels of adaptive pressures depending on the type and degree of biotic and abiotic stresses inherent to each habitat (Stevens, 1989). At any particular location, the abundance and distribution of individual plant species vary tremendously and is theorized to be based on the ability to tolerate a wide range of edaphic conditions and habitat-specific stresses (Pianka, 1966). The ability of individual plant species to thrive in diverse habitats is commonly referred to as phenotypic plasticity and is thought to involve adaptations based on changes in the plant genome (Givnish, 2002; Pan et al., 2006; Robe and Griffiths, 2000; Schurr et al., 2006). Habitats that impose high levels of abiotic stress are typically colonized with fewer plant species compared to habitats imposing low levels of stress. Moreover, high stress habitats have decreased levels of plant abundance compared to low stress habitats even though these habitats may occur in close proximity to one another (Perelman et al., 2007). This is particularly interesting because all plants are known to perceive, transmit signals, and respond to abiotic stresses such as drought, heat, and salinity (Bartels and Sunkar, 2005; Bohnert et al., 1995). Although there has been extensive research performed to determine the genetic, molecular, and physiological bases of how plants respond to and tolerate stress, the nature of plant adaptation to high stress habitats remains unresolved (Leone et al., 2003; Maggio et al., 2003; Tuberosa et al., 2003). However, recent evidence indicates that a ubiquitous aspect of plant biology (fungal symbiosis) is involved in the adaptation and survival of at least some plants in high stress habitats (Rodriguez et al., 2008).

  14. Gene Expression Analysis: A Way to Study Tolerance to Abiotic Stresses in Crops Species Análisis de la Expresión Génica: Una Forma de Estudiar la Tolerancia a Estreses Abióticos en Cultivos

    Directory of Open Access Journals (Sweden)

    Eduardo Pérez-Torres

    2009-06-01

    Full Text Available Regions traditionally destined to agriculture report an ever increasing exposure to cold and drought conditions. This is especially important in countries like Chile where crop management options are limited. The development of new cultivars with better yields under adverse conditions is fundamental if the ever increasing demand for food is to be matched; however, improving tolerance to abiotic stresses has proved to be a complex task. In this regard, development in plant physiology and genomics in the last 20 years has led to a deeper understanding of how plants respond to stress and mechanisms responsible for different ranges of tolerance observed in nature. This review discusses the techniques currently most in use in gene expression analysis, together with some important experimental design variables, such as the developmental stage of the plant, stress intensity and duration, and how different stresses may interact when performing assays. On the other hand, it is fundamental to properly select gene expression techniques according to the available information on the genome, the crop and the final objective of the research. All these points must be considered to ease transition from genomics to practical applications to crop species in order to increase their tolerance to stress. In this regard, the rapid development of new techniques in gene expression analysis with lower costs will determine a new revolution in crop research in coming decades. Therefore, Chile needs to be prepared in this area to continue its development as a major food producer worldwide.Las regiones agrícolas están cada vez más expuestas a condiciones de frío y sequía, algo especialmente importante en países con opciones limitadas de manejo de cultivos como Chile. Si la creciente demanda por alimento ha de ser cubierta, es necesaria la compleja tarea del desarrollo de nuevos cultivares con mejores rendimientos bajo condiciones de estrés. El desarrollo de la

  15. Prerequisites, performance and profits of transcriptional profiling the abiotic stress response.

    Science.gov (United States)

    Kilian, Joachim; Peschke, Florian; Berendzen, Kenneth W; Harter, Klaus; Wanke, Dierk

    2012-02-01

    During the last decade, microarrays became a routine tool for the analysis of transcripts in the model plant Arabidopsis thaliana and the crop plant species rice, poplar or barley. The overwhelming amount of data generated by gene expression studies is a valuable resource for every scientist. Here, we summarize the most important findings about the abiotic stress responses in plants. Interestingly, conserved patterns of gene expression responses have been found that are common between different abiotic stresses or that are conserved between different plant species. However, the individual histories of each plant affect the inter-comparability between experiments already before the onset of the actual stress treatment. This review outlines multiple aspects of microarray technology and highlights some of the benefits, limitations and also pitfalls of the technique. This article is part of a Special Issue entitled: Plant gene regulation in response to abiotic stress.

  16. A comprehensive genome-wide study on tissue-specific and abiotic stress-specific miRNAs in Triticum aestivum.

    Directory of Open Access Journals (Sweden)

    Ritu Pandey

    Full Text Available Productivity of wheat crop is largely dependent on its growth and development that, in turn, is mainly regulated by environmental conditions, including abiotic stress factors. miRNAs are key regulators of gene expression networks involved in diverse aspects of development and stress responses in plants. Using high-throughput sequencing of eight small RNA libraries prepared from diverse abiotic stresses and tissues, we identified 47 known miRNAs belonging to 20 families, 49 true novel and 1030 candidate novel miRNAs. Digital gene expression analysis revealed that 257 miRNAs exhibited tissue-specific expression and 74 were associated with abiotic stresses. Putative target genes were predicted for miRNAs identified in this study and their grouping into functional categories indicated that the putative targets were involved in diverse biological processes. RLM-RACE of predicted targets of three known miRNAs (miR156, miR160 and miR164 confirmed their mRNA cleavage, thus indicating their regulation at post-transcriptional level by the corresponding miRNAs. Mapping of the sequenced data onto the wheat progenitors and closely related monocots revealed a large number of evolutionary conserved miRNAs. Additional expression profiling of some of these miRNAs in other abiotic stresses underline their involvement in multiple stresses. Our findings provide valuable resource for an improved understanding of the role of miRNAs in stress tolerance as well as plant development.

  17. Supplementary data: Responses to combined abiotic and biotic stress in tomato are governed by stress intensity and mechanism of resistance

    NARCIS (Netherlands)

    Kissoudis, C.; Sri Sunarti, Sri; Wiel, van de C.C.M.; Visser, R.G.F.; Linden, van der C.G.; Bai, Y.

    2016-01-01

    Stress conditions in agricultural ecosystems can occur in variable intensities. Different resistance mechanisms to abiotic stress and pathogens are deployed by plants. Thus, it is important to examine plant responses to stress combinations under different scenarios. Here, we evaluated the effect of

  18. Responses to combined abiotic and biotic stress in tomato are governed by stress intensity and resistance mechanism

    NARCIS (Netherlands)

    Kissoudis, Christos; Sri Sunarti, Sri; De Wiel, Van Clemens; Visser, Richard G.F.; Linden, van der Gerard; Bai, Yuling

    2016-01-01

    Stress conditions in agricultural ecosystems can occur at variable intensities. Different resistance mechanisms against abiotic stress and pathogens are deployed by plants. Thus, it is important to examine plant responses to stress combinations under different scenarios. Here, we evaluated the effec

  19. Pre-mRNA splicing repression triggers abiotic stress signaling in plants

    KAUST Repository

    Ling, Yu

    2016-09-24

    Alternative splicing (AS) of precursor RNAs enhances transcriptome plasticity and proteome diversity in response to diverse growth and stress cues. Recent work has shown that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various inhibitors of AS. Here, we show that the macrolide pladienolide B (PB) inhibits constitutive splicing and AS in plants. Also, our RNA sequencing (RNA-seq) data revealed that PB mimics abiotic stress signals including salt, drought and abscisic acid (ABA). PB activates the abiotic stress- and ABA-responsive reporters RD29A

  20. Stress-inducible GmGSTU4 shapes transgenic tobacco plants metabolome towards increased salinity tolerance

    NARCIS (Netherlands)

    Kissoudis, Christos; Kalloniati, Chrissanthi; Flemetakis, Emmanouil; Madesis, Panagiotis; Labrou, Nikolaos E.; Tsaftaris, Athanasios; Nianiou-Obeidat, Irini

    2015-01-01

    The involvement of glutathione transferases (GSTs) in plant’s tolerance to abiotic stresses has been extensively studied; however, the metabolic changes occurring in the plants with altered GSTs expression have not been studied in detail. We have previously demonstrated that GmGSTU4 overexpressio

  1. Putrescine accumulation in Arabidopsis thaliana transgenic lines enhances tolerance to dehydration and freezing stress

    OpenAIRE

    Alet, Analía I; Sanchez, Diego H; Cuevas, Juan C.; del Valle, Secundino; Altabella, Teresa; Tiburcio, Antonio F.; Marco, Francisco; Ferrando, Alejandro; Espasandín, Fabiana D; María E. González; Carrasco, Pedro; Ruiz, Oscar A.

    2011-01-01

    Polyamines have been globally associated to plant responses to abiotic stress. Particularly, putrescine has been related to a better response to cold and dehydration stresses. It is known that this polyamine is involved in cold tolerance, since Arabidopsis thaliana plants mutated in the key enzyme responsible for putrescine synthesis (arginine decarboxilase, ADC; EC 4.1.1.19) are more sensitive than the wild type to this stress. Although it is speculated that the overexpression of ADC genes m...

  2. Comparative physiological and transcriptomic analyses provide integrated insight into osmotic, cold, and salt stress tolerance mechanisms in banana

    Science.gov (United States)

    Hu, Wei; Ding, Zehong; Tie, Weiwei; Yan, Yan; Liu, Yang; Wu, Chunlai; Liu, Juhua; Wang, Jiashui; Peng, Ming; Xu, Biyu; Jin, Zhiqiang

    2017-01-01

    The growth, development, and production of banana plants are constrained by multiple abiotic stressors. However, it remains elusive for the tolerance mechanisms of banana responding to multiple abiotic stresses. In this study, we found that Fen Jiao (FJ) was more tolerant to osmotic, cold, and salt stresses than BaXi Jiao (BX) by phenotypic and physiological analyses. Comparative transcriptomic analyses highlighted stress tolerance genes that either specifically regulated in FJ or changed more than twofold in FJ relative to BX after treatments. In total, 933, 1644, and 133 stress tolerance genes were identified after osmotic, cold, and salt treatments, respectively. Further integrated analyses found that 30 tolerance genes, including transcription factor, heat shock protein, and E3 ubiquitin protein ligase, could be commonly regulated by osmotic, cold, and salt stresses. Finally, ABA and ROS signaling networks were found to be more active in FJ than in BX under osmotic, cold, and salt treatments, which may contribute to the strong stress tolerances of FJ. Together, this study provides new insights into the tolerance mechanism of banana responding to multiple stresses, thus leading to potential applications in the genetic improvement of multiple abiotic stress tolerances in banana. PMID:28223714

  3. Assessing the effects of abiotic stress and livestock grazing disturbance on an alpine grassland with CSR model

    Science.gov (United States)

    Wang, Jun; Luo, Peng; Mou, Chengxiang; Yang, Hao; Mo, Li; Luo, Chuan; Kattge, Jens

    2016-04-01

    How the abiotic factors represented by cold environment and biotic factors represented by livestock grazing will affect the vegetation structure of alpine grassland is a core issue in understanding the cause of biodiversity change on Tibetan Plateau. Past studies on changes of floristic composition, growth forms did not adequately answer question. Given the fact that the response of plant to environment change depend on its life strategy, a synthetical method that based on plant life strategy may deepen our understanding of the mechanism. Using Grime's concept of CSR plant classification, we carried out a vegetation survey along a gradient (three levels) of graze intensity on the south-east of Tibet Plateau, in order to evaluate the role and mechanism of abiotic stress and grazing disturbance in driving plant diversity change, by analyzing the plant life strategy compositions in each of the community and by comparing the characteristic of the strategy compositions along the graze gradient. When the graze intensity was relative low, the dominant plant life strategy gathered in the stress tolerance corner, which conformed the theory of environmental filter, indicating that the ideal top plant community may be dominated by the species with stress tolerant strategy. We also found that the response of strategy dominance to graze intensity increase is positively correlated with the competitive capacity (R 2=0.671; PCSR plant strategy be a useful tool to evaluate the effects of abiotic and biotic factors on plant community assembly of alpine grassland, which may contribute to predict the impacts of climate change and human activity on alpine grassland plant diversity and ecosystem service function related.

  4. Genome-wide analysis of the AP2/ERF superfamily genes and their responses to abiotic stress in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Yongjun eShu

    2016-01-01

    Full Text Available The AP2/ERF superfamily is a large, plant-specific transcription factor family that is involved in many important processes, including plant growth, development and stress responses. Using Medicago truncatula genome information, we identified and characterized 123 putative AP2/ERF genes, which were named as MtERF1–123. These genes were classified into four families based on phylogenetic analysis, which is consistent with the results of other plant species. MtERF genes are distributed throughout all chromosomes but are clustered on various chromosomes due to genomic tandem and segmental duplication. Using transcriptome, high-throughput sequencing data and qRT-PCR analysis, we assessed the expression patterns of the MtERF genes in tissues during development and under abiotic stresses. In total, 87 MtERF genes were expressed in plant tissues, most of which were expressed in specific tissues during development or under specific abiotic stress treatments. These results support the notion that MtERF genes are involved in developmental regulation and environmental responses in M. truncatula. Furthermore, a cluster of DREB subfamily members on chromosome 6 was induced by both cold and freezing stress, representing a positive gene regulatory response under low temperature stress, which suggests that these genes might contribute to freezing tolerance to M. truncatula. In summary, our genome-wide characterization, evolutionary analysis and expression pattern analysis of MtERF genes in M. truncatula provides valuable information for characterizing the molecular functions of these genes and utilizing them to improve stress tolerance in plants.

  5. Genome-Wide Analysis of the AP2/ERF Superfamily Genes and their Responses to Abiotic Stress in Medicago truncatula

    Science.gov (United States)

    Shu, Yongjun; Liu, Ying; Zhang, Jun; Song, Lili; Guo, Changhong

    2016-01-01

    The AP2/ERF superfamily is a large, plant-specific transcription factor family that is involved in many important processes, including plant growth, development, and stress responses. Using Medicago truncatula genome information, we identified and characterized 123 putative AP2/ERF genes, which were named as MtERF1–123. These genes were classified into four families based on phylogenetic analysis, which is consistent with the results of other plant species. MtERF genes are distributed throughout all chromosomes but are clustered on various chromosomes due to genomic tandem and segmental duplication. Using transcriptome, high-throughput sequencing data, and qRT-PCR analysis, we assessed the expression patterns of the MtERF genes in tissues during development and under abiotic stresses. In total, 87 MtERF genes were expressed in plant tissues, most of which were expressed in specific tissues during development or under specific abiotic stress treatments. These results support the notion that MtERF genes are involved in developmental regulation and environmental responses in M. truncatula. Furthermore, a cluster of DREB subfamily members on chromosome 6 was induced by both cold and freezing stress, representing a positive gene regulatory response under low temperature stress, which suggests that these genes might contribute to freezing tolerance to M. truncatula. In summary, our genome-wide characterization, evolutionary analysis, and expression pattern analysis of MtERF genes in M. truncatula provides valuable information for characterizing the molecular functions of these genes and utilizing them to improve stress tolerance in plants. PMID:26834762

  6. Kresoxim-methyl primes Medicago truncatula plants against abiotic stress factors via altered reactive oxygen and nitrogen species signalling leading to downstream transcriptional and metabolic readjustment.

    Science.gov (United States)

    Filippou, Panagiota; Antoniou, Chrystalla; Obata, Toshihiro; Van Der Kelen, Katrien; Harokopos, Vaggelis; Kanetis, Loukas; Aidinis, Vassilis; Van Breusegem, Frank; Fernie, Alisdair R; Fotopoulos, Vasileios

    2016-03-01

    Biotic and abiotic stresses, such as fungal infection and drought, cause major yield losses in modern agriculture. Kresoxim-methyl (KM) belongs to the strobilurins, one of the most important classes of agricultural fungicides displaying a direct effect on several plant physiological and developmental processes. However, the impact of KM treatment on salt and drought stress tolerance is unknown. In this study we demonstrate that KM pre-treatment of Medicago truncatula plants results in increased protection to drought and salt stress. Foliar application with KM prior to stress imposition resulted in improvement of physiological parameters compared with stressed-only plants. This protective effect was further supported by increased proline biosynthesis, modified reactive oxygen and nitrogen species signalling, and attenuation of cellular damage. In addition, comprehensive transcriptome analysis identified a number of transcripts that are differentially accumulating in drought- and salinity-stressed plants (646 and 57, respectively) after KM pre-treatment compared with stressed plants with no KM pre-treatment. Metabolomic analysis suggests that the priming role of KM in drought- and to a lesser extent in salinity-stressed plants can be attributed to the regulation of key metabolites (including sugars and amino acids) resulting in protection against abiotic stress factors. Overall, the present study highlights the potential use of this commonly used fungicide as a priming agent against key abiotic stress conditions.

  7. ATP-sulfurylase, sulfur-compounds and plant stress tolerance

    Directory of Open Access Journals (Sweden)

    Naser A. Anjum

    2015-04-01

    Full Text Available Sulfur (S stands fourth in the list of major plant nutrients after N, P and K. Sulfate (SO42-, a form of soil-S taken up by plant roots is metabolically inert. As the first committed step of S-assimilation, ATP-sulfurylase (ATP-S catalyzes SO42--activation and yields activated high-energy compound adenosine-5′-phosphosulfate (APS that is reduced to sulfide (S2- and incorporated into cysteine (Cys. In turn, Cys acts as a precursor or donor of reduced S for a range of S-compounds such as methionine (Met, glutathione (GSH, homo-GSH (h-GSH and phytochelatins (PCs. Among S-compounds, GSH, h-GSH and PCs are known for their involvement in plant tolerance to varied abiotic stresses, Cys is a major component of GSH, h-GSH and PCs; whereas, several key stress-metabolites such as ethylene, are controlled by Met through its first metabolite S-adenosylmethionine. With the major aim of briefly highlighting S-compound-mediated role of ATP-S in plant stress tolerance, this paper: (a overviews ATP-S structure/chemistry and occurrence, (b appraises recent literature available on ATP-S roles and regulations, and underlying mechanisms in plant abiotic and biotic stress tolerance, (c summarizes ATP-S-intrinsic regulation by major S-compounds, and (d highlights major open-questions in the present context. Future research in the current direction can be devised based on the outcomes of the discussion.

  8. Arabidopsis microRNA expression regulation in a wide range of abiotic stress responses.

    Science.gov (United States)

    Barciszewska-Pacak, Maria; Milanowska, Kaja; Knop, Katarzyna; Bielewicz, Dawid; Nuc, Przemyslaw; Plewka, Patrycja; Pacak, Andrzej M; Vazquez, Franck; Karlowski, Wojciech; Jarmolowski, Artur; Szweykowska-Kulinska, Zofia

    2015-01-01

    Arabidopsis microRNA expression regulation was studied in a wide array of abiotic stresses such as drought, heat, salinity, copper excess/deficiency, cadmium excess, and sulfur deficiency. A home-built RT-qPCR mirEX platform for the amplification of 289 Arabidopsis microRNA transcripts was used to study their response to abiotic stresses. Small RNA sequencing, Northern hybridization, and TaqMan® microRNA assays were performed to study the abundance of mature microRNAs. A broad response on the level of primary miRNAs (pri-miRNAs) was observed. However, stress response at the level of mature microRNAs was rather confined. The data presented show that in most instances, the level of a particular mature miRNA could not be predicted based on the level of its pri-miRNA. This points to an essential role of posttranscriptional regulation of microRNA expression. New Arabidopsis microRNAs responsive to abiotic stresses were discovered. Four microRNAs: miR319a/b, miR319b.2, and miR400 have been found to be responsive to several abiotic stresses and thus can be regarded as general stress-responsive microRNA species.

  9. Tomato NAC transcription factor SlSRN1 positively regulates defense response against biotic stress but negatively regulates abiotic stress response.

    Directory of Open Access Journals (Sweden)

    Bo Liu

    Full Text Available Biotic and abiotic stresses are major unfavorable factors that affect crop productivity worldwide. NAC proteins comprise a large family of transcription factors that play important roles in plant growth and development as well as in responses to biotic and abiotic stresses. In a virus-induced gene silencing-based screening to identify genes that are involved in defense response against Botrytis cinerea, we identified a tomato NAC gene SlSRN1 (Solanum lycopersicum Stress-related NAC1. SlSRN1 is a plasma membrane-localized protein with transactivation activity in yeast. Expression of SlSRN1 was significantly induced by infection with B. cinerea or Pseudomonas syringae pv. tomato (Pst DC3000, leading to 6-8 folds higher than that in the mock-inoculated plants. Expression of SlSRN1 was also induced by salicylic acid, jasmonic acid and 1-amino cyclopropane-1-carboxylic acid and by drought stress. Silencing of SlSRN1 resulted in increased severity of diseases caused by B. cinerea and Pst DC3000. However, silencing of SlSRN1 resulted in increased tolerance against oxidative and drought stresses. Furthermore, silencing of SlSRN1 accelerated accumulation of reactive oxygen species but attenuated expression of defense genes after infection by B. cinerea. Our results demonstrate that SlSRN1 is a positive regulator of defense response against B. cinerea and Pst DC3000 but is a negative regulator for oxidative and drought stress response in tomato.

  10. Identifying Differences in Abiotic Stress Gene Networks between Lowland and Upland Ecotypes of Switchgrass (DE-SC0008338)

    Energy Technology Data Exchange (ETDEWEB)

    Childs, Kevin [Michigan State Univ., East Lansing, MI (United States); Buell, Robin [Michigan State Univ., East Lansing, MI (United States); Zhao, Bingyu [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Zhang, Xunzhong [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2016-11-10

    Switchgrass (Panicum virgatum) is a warm-season C4 grass that is a target lignocellulosic biofuel species for use in the United States due to its local adaption capabilities and high biomass accumulation. Two ecotypes of switchgrass have been described. Members of the lowland ecotype are taller, have narrower leaf blades and generate more biomass compared to individuals from the upland ecotype. Additionally, lowland plants are generally found in the southern United States while upland switchgrass is more typically present in the northern United States. These differences are important as it is envisioned that switchgrass for biofuel production will typically be grown on marginal lands in the northern United States to supplement and diversify farmers' traditional crop incomes. While lowland switchgrass is more productive, it has poor winter survivability in northern latitudes where upland switchgrass is expected to be grown for biofuel use. Abiotic stresses likely to be encountered by switchgrass include drought and salinity. Despite initially being described as preferring wetter environments, members of the lowland ecotype have been characterized as being more drought tolerant than plants of the upland ecotype. Nonetheless, direct trials have indicated that variation for drought tolerance exists in both ecotypes, but prior to this project, only a relatively small number of switchgrass lines had been tested for drought responses. Similarly, switchgrass cultivars have not been widely tested for salt tolerance, but a few studies have shown that even mild salt stress can inhibit growth. The effects of drought and salt stress on plant growth are complex. Both drought and salinity affect the osmotic potential of plant cells and negatively affect plant growth due to reduced water potential and reduced photosynthesis that results from lower stomatal conductance of CO2. Plants respond to drought and salt stress by activating genes that directly attempt to

  11. Isolation of Mesophyll Protoplasts from Mediterranean Woody Plants for the Study of DNA Integrity under Abiotic Stress.

    Science.gov (United States)

    Kuzminsky, Elena; Meschini, Roberta; Terzoli, Serena; Pavani, Liliana; Silvestri, Cristian; Choury, Zineb; Scarascia-Mugnozza, Giuseppe

    2016-01-01

    Abiotic stresses have considerable negative impact on Mediterranean plant ecosystems and better comprehension of the genetic control of response and adaptation of trees to global changes is urgently needed. The single cell gel electrophoresis (SCGE) assay could be considered a good estimator of DNA damage in an individual eukaryotic cell. This method has been mainly employed in animal tissues, because the plant cell wall represents an obstacle for the extraction of nuclei; moreover, in Mediterranean woody species, especially in the sclerophyll plants, this procedure can be quite difficult because of the presence of sclerenchyma and hardened cells. On the other hand, these plants represent an interesting material to be studied because of the ability of these plants to tolerate abiotic stress. For instance, holm oak (Quercus ilex L.) has been selected as the model plant to identify critical levels of O3 for Southern European forests. Consequently, a quantitative method for the evaluation of cell injury of leaf tissues of this species is required. Optimal conditions for high-yield nuclei isolation were obtained by using protoplast technology and a detailed description of the method is provided and discussed. White poplar (Populus alba L.) was used as an internal control for protoplast isolation. Such a method has not been previously reported in newly fully developed leaves of holm oak. This method combined with SCGE assay represents a new tool for testing the DNA integrity of leaf tissues in higher plants under stress conditions.

  12. ISOLATION OF MESOPHYLL PROTOPLASTS FROM MEDITERRANEAN WOODY PLANTS FOR THE STUDY OF DNA INTEGRITY UNDER ABIOTIC STRESS

    Directory of Open Access Journals (Sweden)

    Elena Kuzminsky

    2016-08-01

    Full Text Available Abiotic stresses have considerable negative impact on Mediterranean plant ecosystems and better comprehension of the genetic control of response and adaptation of trees to global changes is urgently needed. The Single Cell Gel Electrophoresis assay could be considered a good estimator of DNA damage in an individual eukaryotic cell. This method has been mainly employed in animal tissues, because the plant cell wall represents an obstacle for the extraction of nuclei; moreover, in Mediterranean woody species, especially in the sclerophyll plants, this procedure can be quite difficult because of the presence of sclerenchyma and hardened cells. On the other hand, these plants represent an interesting material to be studied because of the ability of these plants to tolerate abiotic stress. For instance, holm oak (Quercus ilex L. has been selected as the model plant to identify critical levels of O3 for Southern European forests. Consequently, a quantitative method for the evaluation of cell injury of leaf tissues of this species is required. Optimal conditions for high-yield nuclei isolation were obtained by using protoplast technology and a detailed description of the method is provided and discussed. White poplar (Populus alba L. was used as an internal control for protoplast isolation. Such a method has not been previously reported in newly fully developed leaves of holm oak. This method combined with Single Cell Gel Electrophoresis assay represents a new tool for testing the DNA integrity of leaf tissues in higher plants under stress conditions.

  13. AhpC (alkyl hydroperoxide reductase) from Anabaena sp. PCC 7120 protects Escherichia coli from multiple abiotic stresses

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Yogesh; Chaurasia, Neha [Molecular Biology Section, Laboratory of Algal Biology, Center of Advanced Study in Botany, Banaras Hindu University, Varanasi-221005 (India); Rai, Lal Chand, E-mail: lcraibhu@gmail.com [Molecular Biology Section, Laboratory of Algal Biology, Center of Advanced Study in Botany, Banaras Hindu University, Varanasi-221005 (India)

    2009-04-17

    Alkyl hydroperoxide reductase (AhpC) is known to detoxify peroxides and reactive sulfur species (RSS). However, the relationship between its expression and combating of abiotic stresses is still not clear. To investigate this relationship, the genes encoding the alkyl hydroperoxide reductase (ahpC) from Anabaena sp. PCC 7120 were introduced into E. coli using pGEX-5X-2 vector and their possible functions against heat, salt, carbofuron, cadmium, copper and UV-B were analyzed. The transformed E. coli cells registered significantly increase in growth than the control cells under temperature (47 {sup o}C), NaCl (6% w/v), carbofuron (0.025 mg ml{sup -1}), CdCl{sub 2} (4 mM), CuCl{sub 2} (1 mM), and UV-B (10 min) exposure. Enhanced expression of ahpC gene as measured by semi-quantitative RT-PCR under aforementioned stresses at different time points demonstrated its role in offering tolerance against multiple abiotic stresses.

  14. Identification and expression of the WRKY transcription factors of Carica papaya in response to abiotic and biotic stresses.

    Science.gov (United States)

    Pan, Lin-Jie; Jiang, Ling

    2014-03-01

    The WRKY transcription factor (TF) plays a very important role in the response of plants to various abiotic and biotic stresses. A local papaya database was built according to the GenBank expressed sequence tag database using the BioEdit software. Fifty-two coding sequences of Carica papaya WRKY TFs were predicted using the tBLASTn tool. The phylogenetic tree of the WRKY proteins was classified. The expression profiles of 13 selected C. papaya WRKY TF genes under stress induction were constructed by quantitative real-time polymerase chain reaction. The expression levels of these WRKY genes in response to 3 abiotic and 2 biotic stresses were evaluated. TF807.3 and TF72.14 are upregulated by low temperature; TF807.3, TF43.76, TF12.199 and TF12.62 are involved in the response to drought stress; TF9.35, TF18.51, TF72.14 and TF12.199 is involved in response to wound; TF12.199, TF807.3, TF21.156 and TF18.51 was induced by PRSV pathogen; TF72.14 and TF43.76 are upregulated by SA. The regulated expression levels of above eight genes normalized against housekeeping gene actin were significant at probability of 0.01 levels. These WRKY TFs could be related to corresponding stress resistance and selected as the candidate genes, especially, the two genes TF807.3 and TF12.199, which were regulated notably by four stresses respectively. This study may provide useful information and candidate genes for the development of transgenic stress tolerant papaya varieties.

  15. Evaluation of corn genotypes for drought and heat stress tolerance using physiological measurements and a microcontroller-based monitoring system

    Science.gov (United States)

    Moisture deficit accompanied by high temperature are major abiotic stress factors that affect corn production in the southern United States, particularly during the reproductive stage of the plant. In evaluating plants for environmental stress tolerance, it is important to monitor changes in their ...

  16. Over-expression of a Rab family GTPase from phreatophyte Prosopis juliflora confers tolerance to salt stress on transgenic tobacco.

    Science.gov (United States)

    George, Suja; Parida, Ajay

    2011-03-01

    Plant growth and productivity are adversely affected by various abiotic and biotic stress factors. In our previous study, we used Prosopis juliflora, an abiotic stress tolerant tree species of Fabaceae, as a model plant system for isolating genes functioning in abiotic stress tolerance. Here we report the isolation and characterization of a Rab family GTPase from P. juliflora (Pj Rab7) and the ability of this gene to confer salt stress tolerance in transgenic tobacco. Northern analysis for Pj Rab7 in P. juliflora leaf tissue revealed up-regulation of this gene under salt stress under the concentrations and time points analyzed. Pj Rab7 transgenic tobacco lines survived better under conditions of 150 mM NaCl stress compared to control un-transformed plants. Pj Rab7 transgenic plants were found to accumulate more sodium than control plants during salt stress. The results of our studies could be used as a starting point for generation of crop plants tolerant to abiotic stress.

  17. Using biotechnology and genomics to improve biotic and abiotic stress in apple

    Science.gov (United States)

    Genomic sequencing, molecular biology, and transformation technologies are providing valuable tools to better understand the complexity of how plants develop, function, and respond to biotic and abiotic stress. These approaches should complement but not replace a solid understanding of whole plant ...

  18. Natural variation for gene expression responses to abiotic stress in maize.

    Science.gov (United States)

    Waters, Amanda J; Makarevitch, Irina; Noshay, Jaclyn; Burghardt, Liana T; Hirsch, Candice N; Hirsch, Cory D; Springer, Nathan M

    2017-02-01

    Plants respond to abiotic stress through a variety of physiological, biochemical, and transcriptional mechanisms. Many genes exhibit altered levels of expression in response to abiotic stress, which requires concerted action of both cis- and trans-regulatory features. In order to study the variability in transcriptome response to abiotic stress, RNA sequencing was performed using 14-day-old maize seedlings of inbreds B73, Mo17, Oh43, PH207 and B37 under control, cold and heat conditions. Large numbers of genes that responded differentially to stress between parental inbred lines were identified. RNA sequencing was also performed on similar tissues of the F1 hybrids produced by crossing B73 and each of the three other inbred lines. By evaluating allele-specific transcript abundance in the F1 hybrids, we were able to measure the abundance of cis- and trans-regulatory variation between genotypes for both steady-state and stress-responsive expression differences. Although examples of trans-regulatory variation were observed, cis-regulatory variation was more common for both steady-state and stress-responsive expression differences. The genes with cis-allelic variation for response to cold or heat stress provided an opportunity to study the basis for regulatory diversity.

  19. Evolution and Adaptation of Wild Emmer Wheat Populations to Biotic and Abiotic Stresses.

    Science.gov (United States)

    Huang, Lin; Raats, Dina; Sela, Hanan; Klymiuk, Valentina; Lidzbarsky, Gabriel; Feng, Lihua; Krugman, Tamar; Fahima, Tzion

    2016-08-04

    The genetic bottlenecks associated with plant domestication and subsequent selection in man-made agroecosystems have limited the genetic diversity of modern crops and increased their vulnerability to environmental stresses. Wild emmer wheat, the tetraploid progenitor of domesticated wheat, distributed along a wide range of ecogeographical conditions in the Fertile Crescent, has valuable "left behind" adaptive diversity to multiple diseases and environmental stresses. The biotic and abiotic stress responses are conferred by series of genes and quantitative trait loci (QTLs) that control complex resistance pathways. The study of genetic diversity, genomic organization, expression profiles, protein structure and function of biotic and abiotic stress-resistance genes, and QTLs could shed light on the evolutionary history and adaptation mechanisms of wild emmer populations for their natural habitats. The continuous evolution and adaptation of wild emmer to the changing environment provide novel solutions that can contribute to safeguarding food for the rapidly growing human population.

  20. Advances in functional genomics for investigating salinity stress tolerance mechanisms in cereals

    Directory of Open Access Journals (Sweden)

    Megan C Shelden

    2013-05-01

    Full Text Available Abiotic stresses such as low water availability and high salinity are major causes of cereal crop yield losses and significantly impact on sustainability. Wheat and barley are two of the most important cereal crops (after maize and rice and are grown in increasingly hostile environments with soil salinity and drought both expected to increase this century, reducing the availability of arable land. Barley and wheat are classified as glycophytes (salt-sensitive, yet they are more salt-tolerant than other cereal crops such as rice and so are good models for studying salt-tolerance in cereals. The exploitation of genetic variation of phenotypic traits through plant breeding could significantly improve growth of cereals in salinity-affected regions, thus leading to improved crop yields. Genetic variation in phenotypic traits for abiotic stress tolerance have been identified in land races and wild germplasm but the molecular basis of these differences is often difficult to determine due to the complex genetic nature of these species. High-throughput functional genomics technologies, such as transcriptomics, metabolomics, proteomics and ionomics are powerful tools for investigating the molecular responses of plants to abiotic stress. The advancement of these technologies has allowed for the identification and quantification of transcript /metabolites in specific cell types and/or tissues. Using these new technologies on plants will provide a powerful tool to uncovering genetic traits in more complex species such as wheat and barley and provide novel insights into the molecular mechanisms of salinity stress tolerance.

  1. Arabidopsis cysteine-rich receptor-like kinase 45 functions in the responses to abscisic acid and abiotic stresses

    KAUST Repository

    Zhang, Xiujuan

    2013-06-01

    The phytohormone abscisic acid (ABA) regulates seed germination, plant growth and development, and response to abiotic stresses such as drought and salt stresses. Receptor-like kinases are well known signaling components that mediate plant responses to developmental and environmental stimuli. Here, we characterized the biological function of an ABA and stress-inducible cysteine-rich receptor-like protein kinase, CRK45, in ABA signaling in Arabidopsis thaliana. The crk45 mutant was less sensitive to ABA than the wild type during seed germination and early seedling development, whereas CRK45 overexpression plants were more sensitive to ABA compared to the wild type. Furthermore, overexpression of CRK45 led to hypersensitivity to salt and glucose inhibition of seed germination, whereas the crk45 mutant showed the opposite phenotypes. In addition, CRK45 overexpression plants had enhanced tolerance to drought. Gene expression analyses revealed that the expression of representative stress-responsive genes was significantly enhanced in CRK45 overexpression plants in response to salt stress. ABA biosynthetic genes such as NCED3,. 22NCED3, 9-Cis-Epoxycarotenoid Dioxygenase 3.NCED5,. 33NCED5, 9-Cis-Epoxycarotenoid Dioxygenase 5.ABA2,. 44ABA2, Abscisic Acid Deficient 2. and AAO355AAO3, Abscisic Aldehyde Oxidase 3. were also constitutively elevated in the CRK45 overexpression plants. We concluded that CRK45 plays an important role in ABA signaling that regulates Arabidopsis seeds germination, early seedling development and abiotic stresses response, by positively regulating ABA responses in these processes. © 2013 Elsevier Masson SAS.

  2. Stable expression of mtlD gene imparts multiple stress tolerance in finger millet.

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    Ramanna Hema

    Full Text Available Finger millet is susceptible to abiotic stresses, especially drought and salinity stress, in the field during seed germination and early stages of seedling development. Therefore developing stress tolerant finger millet plants combating drought, salinity and associated oxidative stress in these two growth stages is important. Cellular protection through osmotic adjustment and efficient free radical scavenging ability during abiotic stress are important components of stress tolerance mechanisms in plants. Mannitol, an osmolyte, is known to scavenge hydroxyl radicals generated during various abiotic stresses and thereby minimize stress damage in several plant species. In this study transgenic finger millet plants expressing the mannitol biosynthetic pathway gene from bacteria, mannitol-1-phosphate dehydrogenase (mtlD, were developed through Agrobacterium tumefaciens-mediated genetic transformation. mtlD gene integration in the putative transgenic plants was confirmed by Southern blot. Further, performance of transgenic finger millet under drought, salinity and oxidative stress was studied at plant level in T1 generation and in T1 and T2 generation seedlings. Results from these experiments showed that transgenic finger millet had better growth under drought and salinity stress compared to wild-type. At plant level, transgenic plants showed better osmotic adjustment and chlorophyll retention under drought stress compared to the wild-type. However, the overall increase in stress tolerance of transgenics for the three stresses, especially for oxidative stress, was only marginal compared to other mtlD gene expressing plant species reported in the literature. Moreover, the Agrobacterium-mediated genetic transformation protocol developed for finger millet in this study can be used to introduce diverse traits of agronomic importance in finger millet.

  3. Abiotic Stresses: Insight into Gene Regulation and Protein Expression in Photosynthetic Pathways of Plants

    Directory of Open Access Journals (Sweden)

    Mohammad-Zaman Nouri

    2015-08-01

    Full Text Available Global warming and climate change intensified the occurrence and severity of abiotic stresses that seriously affect the growth and development of plants,especially, plant photosynthesis. The direct impact of abiotic stress on the activity of photosynthesis is disruption of all photosynthesis components such as photosystem I and II, electron transport, carbon fixation, ATP generating system and stomatal conductance. The photosynthetic system of plants reacts to the stress differently, according to the plant type, photosynthetic systems (C3 or C4, type of the stress, time and duration of the occurrence and several other factors. The plant responds to the stresses by a coordinate chloroplast and nuclear gene expression. Chloroplast, thylakoid membrane, and nucleus are the main targets of regulated proteins and metabolites associated with photosynthetic pathways. Rapid responses of plant cell metabolism and adaptation to photosynthetic machinery are key factors for survival of plants in a fluctuating environment. This review gives a comprehensive view of photosynthesis-related alterations at the gene and protein levels for plant adaptation or reaction in response to abiotic stress.

  4. Abiotic Stress Responses and Microbe-Mediated Mitigation in Plants: The Omics Strategies

    Science.gov (United States)

    Meena, Kamlesh K.; Sorty, Ajay M.; Bitla, Utkarsh M.; Choudhary, Khushboo; Gupta, Priyanka; Pareek, Ashwani; Singh, Dhananjaya P.; Prabha, Ratna; Sahu, Pramod K.; Gupta, Vijai K.; Singh, Harikesh B.; Krishanani, Kishor K.; Minhas, Paramjit S.

    2017-01-01

    Abiotic stresses are the foremost limiting factors for agricultural productivity. Crop plants need to cope up adverse external pressure created by environmental and edaphic conditions with their intrinsic biological mechanisms, failing which their growth, development, and productivity suffer. Microorganisms, the most natural inhabitants of diverse environments exhibit enormous metabolic capabilities to mitigate abiotic stresses. Since microbial interactions with plants are an integral part of the living ecosystem, they are believed to be the natural partners that modulate local and systemic mechanisms in plants to offer defense under adverse external conditions. Plant-microbe interactions comprise complex mechanisms within the plant cellular system. Biochemical, molecular and physiological studies are paving the way in understanding the complex but integrated cellular processes. Under the continuous pressure of increasing climatic alterations, it now becomes more imperative to define and interpret plant-microbe relationships in terms of protection against abiotic stresses. At the same time, it also becomes essential to generate deeper insights into the stress-mitigating mechanisms in crop plants for their translation in higher productivity. Multi-omics approaches comprising genomics, transcriptomics, proteomics, metabolomics and phenomics integrate studies on the interaction of plants with microbes and their external environment and generate multi-layered information that can answer what is happening in real-time within the cells. Integration, analysis and decipherization of the big-data can lead to a massive outcome that has significant chance for implementation in the fields. This review summarizes abiotic stresses responses in plants in-terms of biochemical and molecular mechanisms followed by the microbe-mediated stress mitigation phenomenon. We describe the role of multi-omics approaches in generating multi-pronged information to provide a better understanding

  5. Transcriptomic and proteomic response of fruit trees to abiotic stress

    Science.gov (United States)

    Together, temperature and water availability are the primary determinants of the global distribution of major vegetation biomes and as such, have a major impact on the cultivation of temperate fruit trees. The regulation of both low temperature and water deficit stress has been widely studied in he...

  6. Protein Synthesis Inhibition Activity by Strawberry Tissue Protein Extracts during Plant Life Cycle and under Biotic and Abiotic Stresses

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    Walther Faedi

    2013-07-01

    Full Text Available Ribosome-inactivating proteins (RIPs, enzymes that are widely distributed in the plant kingdom, inhibit protein synthesis by depurinating rRNA and many other polynucleotidic substrates. Although RIPs show antiviral, antifungal, and insecticidal activities, their biological and physiological roles are not completely understood. Additionally, it has been described that RIP expression is augmented under stressful conditions. In this study, we evaluated protein synthesis inhibition activity in partially purified basic proteins (hereafter referred to as RIP activity from tissue extracts of Fragaria × ananassa (strawberry cultivars with low (Dora and high (Record tolerance to root pathogens and fructification stress. Association between the presence of RIP activity and the crop management (organic or integrated soil, growth stage (quiescence, flowering, and fructification, and exogenous stress (drought were investigated. RIP activity was found in every tissue tested (roots, rhizomes, leaves, buds, flowers, and fruits and under each tested condition. However, significant differences in RIP distribution were observed depending on the soil and growth stage, and an increase in RIP activity was found in the leaves of drought-stressed plants. These results suggest that RIP expression and activity could represent a response mechanism against biotic and abiotic stresses and could be a useful tool in selecting stress-resistant strawberry genotypes.

  7. Identification of genes involved in the response of Arabidopsis to simultaneous biotic and abiotic stresses.

    Science.gov (United States)

    Atkinson, Nicky J; Lilley, Catherine J; Urwin, Peter E

    2013-08-01

    In field conditions, plants may experience numerous environmental stresses at any one time. Research suggests that the plant response to multiple stresses is different from that for individual stresses, producing nonadditive effects. In particular, the molecular signaling pathways controlling biotic and abiotic stress responses may interact and antagonize one another. The transcriptome response of Arabidopsis (Arabidopsis thaliana) to concurrent water deficit (abiotic stress) and infection with the plant-parasitic nematode Heterodera schachtii (biotic stress) was analyzed by microarray. A unique program of gene expression was activated in response to a combination of water deficit and nematode stress, with 50 specifically multiple-stress-regulated genes. Candidate genes with potential roles in controlling the response to multiple stresses were selected and functionally characterized. RAPID ALKALINIZATION FACTOR-LIKE8 (AtRALFL8) was induced in roots by joint stresses but conferred susceptibility to drought stress and nematode infection when overexpressed. Constitutively expressing plants had stunted root systems and extended root hairs. Plants may produce signal peptides such as AtRALFL8 to induce cell wall remodeling in response to multiple stresses. The methionine homeostasis gene METHIONINE GAMMA LYASE (AtMGL) was up-regulated by dual stress in leaves, conferring resistance to nematodes when overexpressed. It may regulate methionine metabolism under conditions of multiple stresses. AZELAIC ACID INDUCED1 (AZI1), involved in defense priming in systemic plant immunity, was down-regulated in leaves by joint stress and conferred drought susceptibility when overexpressed, potentially as part of abscisic acid-induced repression of pathogen response genes. The results highlight the complex nature of multiple stress responses and confirm the importance of studying plant stress factors in combination.

  8. Abiotic Stresses Downregulate Key Genes Involved in Nitrogen Uptake and Assimilation in Brassica juncea L.

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    Parul Goel

    Full Text Available Abiotic stresses such as salinity, drought and extreme temperatures affect nitrogen (N uptake and assimilation in plants. However, little is known about the regulation of N pathway genes at transcriptional level under abiotic stress conditions in Brassica juncea. In the present work, genes encoding nitrate transporters (NRT, ammonium transporters (AMT, nitrate reductase (NR, nitrite reductase (NiR, glutamine synthetase (GS, glutamate synthase (GOGAT, glutamate dehydrogenase (GDH, asparagines synthetase (ASN were cloned from Brassica juncea L. var. Varuna. The deduced protein sequences were analyzed to predict their subcellular localization, which confirmed localization of all the proteins in their respective cellular organelles. The protein sequences were also subjected to conserved domain identification, which confirmed presence of characteristic domains in all the proteins, indicating their putative functions. Moreover, expression of these genes was studied after 1h and 24h of salt (150 mM NaCl, osmotic (250 mM Mannitol, cold (4°C and heat (42°C stresses. Most of the genes encoding nitrate transporters and enzymes responsible for N assimilation and remobilization were found to be downregulated under abiotic stresses. The expression of BjAMT1.2, BjAMT2, BjGS1.1, BjGDH1 and BjASN2 was downregulated after 1hr, while expression of BjNRT1.1, BjNRT2.1, BjNiR1, BjAMT2, BjGDH1 and BjASN2 was downregulated after 24h of all the stress treatments. However, expression of BjNRT1.1, BjNRT1.5 and BjGDH2 was upregulated after 1h of all stress treatments, while no gene was found to be upregulated after 24h of stress treatments, commonly. These observations indicate that expression of most of the genes is adversely affected under abiotic stress conditions, particularly under prolonged stress exposure (24h, which may be one of the reasons of reduction in plant growth and development under abiotic stresses.

  9. Cytosine methylation alteration in natural populations of Leymus chinensis induced by multiple abiotic stresses.

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    Yingjie Yu

    Full Text Available BACKGROUND: Human activity has a profound effect on the global environment and caused frequent occurrence of climatic fluctuations. To survive, plants need to adapt to the changing environmental conditions through altering their morphological and physiological traits. One known mechanism for phenotypic innovation to be achieved is environment-induced rapid yet inheritable epigenetic changes. Therefore, the use of molecular techniques to address the epigenetic mechanisms underpinning stress adaptation in plants is an important and challenging topic in biological research. In this study, we investigated the impact of warming, nitrogen (N addition, and warming+nitrogen (N addition stresses on the cytosine methylation status of Leymus chinensis Tzvel. at the population level by using the amplified fragment length polymorphism (AFLP, methylation-sensitive amplified polymorphism (MSAP and retrotransposon based sequence-specific amplification polymorphism (SSAP techniques. METHODOLOGY/PRINCIPAL FINDINGS: Our results showed that, although the percentages of cytosine methylation changes in SSAP are significantly higher than those in MSAP, all the treatment groups showed similar alteration patterns of hypermethylation and hypomethylation. It meant that the abiotic stresses have induced the alterations in cytosine methylation patterns, and the levels of cytosine methylation changes around the transposable element are higher than the other genomic regions. In addition, the identification and analysis of differentially methylated loci (DML indicated that the abiotic stresses have also caused targeted methylation changes at specific loci and these DML might have contributed to the capability of plants in adaptation to the abiotic stresses. CONCLUSIONS/SIGNIFICANCE: Our results demonstrated that abiotic stresses related to global warming and nitrogen deposition readily evoke alterations of cytosine methylation, and which may provide a molecular basis for rapid

  10. Antioxidant activity of polyphenols of adzuki bean (Vigna angularis germinated in abiotic stress conditions

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    Urszula Złotek

    2015-03-01

    Full Text Available Background. Adzuki sprouts are one of more valuable but still underappreciated dietary supplements which may be considered as functional food. Sprouting reduces anti-nutritional factors and increases the bioavailability of macro and micronutrients and also affects phytochemical levels. Exposure of plants to abiotic stresses results in change in production of phytochemical compounds. The aim of this study was to assess the content and antioxidant properties of phenolic in adzuki bean seeds germinated in selected abiotic stress conditions. Material and methods. Adzuki bean seeds were germinated in different abiotic stress conditions: thermal, osmotic and oxidative. The content of phenolics in adzuki bean seeds coat extracts and antioxidant activity Fe2+ chelating ability and neutralization of the free radicals generated from DPPH and ABTS were determined. Results. All applied stress conditions (except for thermal stress have caused decrease the content of the analysed phenolic fractions. The lowest amounts of polyphenols in extracts of sprouts obtained in oxidative stress conditions were observed. The highest ability to neutralize free radicals generated with ABTS and DPPH have extracts from sprouts germinated under thermal stress 39.94 and 13.20 μmol TEAC/g d.w., respectively. The lowest – sprouts obtained in oxidative stress conditions (18.2 and 9.72 μmol TEAC/g d.w.. The highest ability to chelate Fe2+ has been shown by the extract from adzuki bean seeds coat subjected to thermal stress (7.06 % and the lowest control extract (3.08%. Conclusions. It can be concluded that only thermal stress contributes to the improvement of antioxidant activity of extracts obtained from adzuki bean seeds coat.

  11. Modulation of thiamine metabolism in Zea mays seedlings under conditions of abiotic stress.

    Science.gov (United States)

    Rapala-Kozik, Maria; Kowalska, Ewa; Ostrowska, Katarzyna

    2008-01-01

    The responses of plants to abiotic stress involve the up-regulation of numerous metabolic pathways, including several major routes that engage thiamine diphosphate (TDP)-dependent enzymes. This suggests that the metabolism of thiamine (vitamin B1) and its phosphate esters in plants may be modulated under various stress conditions. In the present study, Zea mays seedlings were used as a model system to analyse for any relation between the plant response to abiotic stress and the properties of thiamine biosynthesis and activation. Conditions of drought, high salt, and oxidative stress were induced by polyethylene glycol, sodium chloride, and hydrogen peroxide, respectively. The expected increases in the abscisic acid levels and in the activities of antioxidant enzymes including catalase, ascorbate peroxidase, and glutathione reductase were found under each stress condition. The total thiamine compound content in the maize seedling leaves increased under each stress condition applied, with the strongest effects on these levels observed under the oxidative stress treatment. This increase was also found to be associated with changes in the relative distribution of free thiamine, thiamine monophosphate (TMP), and TDP. Surprisingly, the activity of the thiamine synthesizing enzyme, TMP synthase, responded poorly to abiotic stress, in contrast to the significant enhancement found for the activities of the TDP synthesizing enzyme, thiamine pyrophosphokinase, and a number of the TDP/TMP phosphatases. Finally, a moderate increase in the activity of transketolase, one of the major TDP-dependent enzymes, was detectable under conditions of salt and oxidative stress. These findings suggest a role of thiamine metabolism in the plant response to environmental stress.

  12. Stress-tolerant Wild Plants: a Source of Knowledge and Biotechnological Tools for the Genetic Improvement of Stress Tolerance in Crop Plants

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    Monica BOSCAIU

    2012-11-01

    Full Text Available Over the next few decades we must boost crop productivity if we are to feed a growing world population, which will reach more than 9×109 people by 2050; and we should do it in the frame of a sustainable agriculture, with an increasing scarcity of new arable land and of water for irrigation. For all important crops, average yields are only a fraction-somewhere between 20% and 50%-of record yields; these losses are mostly due to drought and high soil salinity, environmental conditions which will worsen in many regions because of global climate change. Therefore, the simplest way to increase agricultural productivity would be to improve the abiotic stress tolerance of crops. Considering the limitations of traditional plant breeding, the most promising strategy to achieve this goal will rely on the generation of transgenic plants expressing genes conferring tolerance. However, advances using this approach have been slow, since it requires a deep understanding of the mechanisms of plant stress tolerance, which are still largely unknown. Paradoxically, most studies on the responses of plants to abiotic stress have been performed using stress-sensitive species-such as Arabidopsis thaliana-although there are plants (halophytes, gypsophytes, xerophytes adapted to extremely harsh environmental conditions in their natural habitats. We propose these wild stress-tolerant species as more suitable models to investigate these mechanisms, as well as a possible source of biotechnological tools (‘stress tolerance’ genes, stress-inducible promoters for the genetic engineering of stress tolerance in crop plants.

  13. The Role of MAPK Modules and ABA during Abiotic Stress Signaling

    KAUST Repository

    Zélicourt, Axel de

    2016-05-01

    To respond to abiotic stresses, plants have developed specific mechanisms that allow them to rapidly perceive and respond to environmental changes. The phytohormone abscisic acid (ABA) was shown to be a pivotal regulator of abiotic stress responses in plants, triggering major changes in plant physiology. The ABA core signaling pathway largely relies on the activation of SnRK2 kinases to mediate several rapid responses, including gene regulation, stomatal closure, and plant growth modulation. Mitogen-activated protein kinases (MAPKs) have also been implicated in ABA signaling, but an entire ABA-activated MAPK module was uncovered only recently. In this review, we discuss the evidence for a role of MAPK modules in the context of different plant ABA signaling pathways. Abiotic stresses impact average yield in agriculture by more than 50% globally.Since ABA is a key regulator of abiotic stress responses, an understanding of its functioning at the molecular level is essential for plant breeding. Although the ABA core signaling pathway has been unraveled, several downstream events are still unclear.MAPKs are involved in most plant developmental stages and in response to stresses. Several members of the MAPK family were shown to be directly or indirectly activated by the ABA core signaling pathway.Recent evidence shows that the complete MAP3K17/18-MKK3-MPK1/2/7/14 module is under the control of ABA, whose members are under the transcriptional and post-translational control of the ABA core signaling pathway. © 2016 Elsevier Ltd.

  14. The Calcium Sensor CBL-CIPK Is Involved in Plant’s Response to Abiotic Stresses

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    S. M. Nuruzzaman Manik

    2015-01-01

    Full Text Available Abiotic stress halts the physiological and developmental process of plant. During stress condition, CBL-CIPK complex is identified as a primary element of calcium sensor to perceive environmental signals. Recent studies established that this complex regulates downstream targets like ion channels and transporters in adverse stages conditions. Crosstalks between the CBL-CIPK complex and different abiotic stresses can extend our research area, which can improve and increase the production of genetically modified crops in response to abiotic stresses. How this complex links with environmental signals and creates adjustable circumstances under unfavorable conditions is now one of the burning issues. Diverse studies are already underway to delineate this signalling mechanism underlying different interactions. Therefore, up to date experimental results should be concisely published, thus paving the way for further research. The present review will concisely recapitulate the recent and ongoing research progress of positive ions (Mg2+, Na+, and K+, negative ions (NO3-, PO4-, and hormonal signalling, which are evolving from accumulating results of analyses of CBL and CIPK loss- or gain-of-function experiments in different species along with some progress and perspectives of our works. In a word, this review will give one step forward direction for more functional studies in this area.

  15. 植物抗坏血酸过氧化物酶的表达调控以及对非生物胁迫的耐受作用%Expression regulation of plant ascorbate peroxidase and its tolerance to abiotic stresses

    Institute of Scientific and Technical Information of China (English)

    李泽琴; 李静晓; 张根发

    2013-01-01

    Ascorbate peroxidase (APX), a type I heme peroxidase, catalyzes oxidation of ascorbic acid. It possesses a high degree of specificity to ascorbic acid. APX gene cluster consists of four sub-clusters: the gene clusters of cytosol, chloroplast, mitochondria, and peroxidase. As a key component of hydrogen peroxide detoxification system, the ascor-bate-glutathione cycle, APX plays a vital role in the metabolism of H2O2 of plant cells. Studies showed that APX is one of the most important enzymes, which modulate the cellular H2O2 level in redox signaling system. The expression mechanisms of APX isoenzymes are quite complex. Briefly, cytosolic APX is regulated by a variety of signals; two chloroplastic APX isoenzymes are tissue-dependently regulated by alternative splicing. Generated APXs could regulate redox signaling in cells, which further boosts plants tolerance to abiotic stresses. This review focuses on recent advances concerning catalytic prop- erties, physiological function, and gene expressing regulation and abio-stress responding mechanism of APX.%抗坏血酸过氧化物酶(Ascorbate peroxidase,APX)属于I 型血红素过氧化物酶,它催化H2O2 依赖的L-抗 坏血酸氧化作用,对抗坏血酸表现出高度的专一性.植物APX 基因家族由4 个亚家族组成,分别为细胞质、叶 绿体、线粒体和过氧化物酶体基因亚家族,每个亚家族中又含有不同的APX 同工酶.作为植物抗坏血酸-谷胱 甘肽循环中的一个关键组分,APX 在细胞H2O2 代谢过程中起着至关重要的作用.研究表明植物APX 是氧化还 原信号系统中调节细胞水平H2O2 非常重要的一种酶,APX 同工酶的表达机制非常复杂,细胞质APX 受多种信 号调节表达,两种叶绿体APX 通过选择性剪接进行组织特异性调节.通过调控产生的APX 可调节细胞中的氧 化还原信号,进而提高植物对非生物胁迫的耐受性.文章综述了植物APX 的催化机制、表达调控机理以及响 应

  16. Toxicity of abiotic stressors to Fusarium species: differences in hydrogen peroxide and fungicide tolerance.

    Science.gov (United States)

    Nagygyörgy, Emese D; Kovács, Barbara; Leiter, Eva; Miskei, Márton; Pócsi, István; Hornok, László; Adám, Attila L

    2014-06-01

    Stress sensitivity of three related phytopathogenic Fusarium species (Fusarium graminearum, Fusarium oxysporum and Fusarium verticillioides) to different oxidative, osmotic, cell wall, membrane, fungicide stressors and an antifungal protein (PAF) were studied in vitro. The most prominent and significant differences were found in oxidative stress tolerance: all the three F. graminearum strains showed much higher sensitivity to hydrogen peroxide and, to a lesser extent, to menadione than the other two species. High sensitivity of F. verticillioides strains was also detectable to an azole drug, Ketoconazole. Surprisingly, no or limited differences were observed in response to other oxidative, osmotic and cell wall stressors. These results indicate that fungal oxidative stress response and especially the response to hydrogen peroxide (this compound is involved in a wide range of plant-fungus interactions) might be modified on niche-specific manner in these phylogenetically related Fusarium species depending on their pathogenic strategy. Supporting the increased hydrogen peroxide sensitivity of F. graminearum, genome-wide analysis of stress signal transduction pathways revealed the absence one CatC-type catalase gene in F. graminearum in comparison to the other two species.

  17. A Non-specific Setaria italica Lipid Transfer Protein Gene Plays a Critical Role under Abiotic Stress

    Science.gov (United States)

    Pan, Yanlin; Li, Jianrui; Jiao, Licong; Li, Cong; Zhu, Dengyun; Yu, Jingjuan

    2016-01-01

    Lipid transfer proteins (LTPs) are a class of cysteine-rich soluble proteins having small molecular weights. LTPs participate in flower and seed development, cuticular wax deposition, also play important roles in pathogen and abiotic stress responses. A non-specific LTP gene (SiLTP) was isolated from a foxtail millet (Setaria italica) suppression subtractive hybridization library enriched for differentially expressed genes after abiotic stress treatments. A semi-quantitative reverse transcriptase PCR analysis showed that SiLTP was expressed in all foxtail millet tissues. Additionally, the SiLTP promoter drove GUS expression in root tips, stems, leaves, flowers, and siliques of transgenic Arabidopsis. Quantitative real-time PCR indicated that the SiLTP expression was induced by NaCl, polyethylene glycol, and abscisic acid (ABA). SiLTP was localized in the cytoplasm of tobacco leaf epidermal cells and maize protoplasts. The ectopic expression of SiLTP in tobacco resulted in higher levels of salt and drought tolerance than in the wild type (WT). To further assess the function of SiLTP, SiLTP overexpression (OE) and RNA interference (RNAi)-based transgenic foxtail millet were obtained. SiLTP-OE lines performed better under salt and drought stresses compared with WT plants. In contrast, the RNAi lines were much more sensitive to salt and drought compared than WT. Electrophoretic mobility shift assays and yeast one-hybrids indicated that the transcription factor ABA-responsive DRE-binding protein (SiARDP) could bind to the dehydration-responsive element of SiLTP promoter in vitro and in vivo, respectively. Moreover, the SiLTP expression levels were higher in SiARDP-OE plants compared than the WT. These results confirmed that SiLTP plays important roles in improving salt and drought stress tolerance of foxtail millet, and may partly be upregulated by SiARDP. SiLTP may provide an effective genetic resource for molecular breeding in crops to enhance salt and drought

  18. Silicon, the silver bullet for mitigating biotic and abiotic stress, and improving grain quality, in rice?

    OpenAIRE

    Meharg,Caroline; Andrew A Meharg

    2015-01-01

    Adequate silicon fertilization greatly boosts rice yield and mitigates biotic and abiotic stress, and improves grain quality through lowering the content of cadmium and inorganic arsenic. This review on silicon dynamics in rice considers recent advances in our understanding of the role of silicon in rice, and the challenges of maintaining adequate silicon fertility within rice paddy systems. Silicon is increasingly considered as an element required for optimal plant performance, particularly ...

  19. Proteomics: a tool for the study of plant response to abiotic stress

    OpenAIRE

    Hoyos Roveda, Gabriel; Fonseca Moreno, Liz Patricia

    2011-01-01

    Due in part to human activity, changes in global climate behavior have manifested in an increase in extreme temperature related events such as drought, salinization, contamination and flooding of vast areas of the planet. Regarding agricultural activity, these uncertain climatic scenarios are likely to cause biotic and abiotic stress increases, which must be dealt with through science and technology. Holistic approaches, also known as “omics”: proteomics, genomics, transcriptomics, and metabo...

  20. Molecular marker assisted gene stacking for biotic and abiotic stress resistance genes in an elite rice cultivar.

    Science.gov (United States)

    Das, Gitishree; Rao, G J N

    2015-01-01

    Severe yield loss due to various biotic stresses like bacterial blight (BB), gall midge (insect) and Blast (disease) and abiotic stresses like submergence and salinity are a serious constraint to the rice productivity throughout the world. The most effective and reliable method of management of the stresses is the enhancement of host resistance, through an economical and environmentally friendly approach. Through the application of marker assisted selection (MAS) technique, the present study reports a successful pyramidization of genes/QTLs to confer resistance/tolerance to blast (Pi2, Pi9), gall Midge (Gm1, Gm4), submergence (Sub1), and salinity (Saltol) in a released rice variety CRMAS2621-7-1 as Improved Lalat which had already incorporated with three BB resistance genes xa5, xa13, and Xa21 to supplement the Xa4 gene present in Improved Lalat. The molecular analysis revealed clear polymorphism between the donor and recipient parents for all the markers that are tagged to the target traits. The conventional backcross breeding approach was followed till BC3F1 generation and starting from BC1F1 onwards, marker assisted selection was employed at each step to monitor the transfer of the target alleles with molecular markers. The different BC3F1s having the target genes/QTLs were inter crossed to generate hybrids with all 10 stress resistance/tolerance genes/QTLs into a single plant/line. Homozygous plants for resistance/tolerance genes in different combinations were recovered. The BC3F3 lines were characterized for their agronomic and quality traits and promising progeny lines were selected. The SSR based background selection was done. Most of the gene pyramid lines showed a high degree of similarity to the recurrent parent for both morphological, grain quality traits and in SSR based background selection. Out of all the gene pyramids tested, two lines had all the 10 resistance/tolerance genes and showed adequate levels of resistance/tolerance against the five target

  1. Hypothesis/review: contribution of putrescine to 4-aminobutyrate (GABA) production in response to abiotic stress.

    Science.gov (United States)

    Shelp, Barry J; Bozzo, Gale G; Trobacher, Christopher P; Zarei, Adel; Deyman, Kristen L; Brikis, Carolyne J

    2012-09-01

    4-Aminobutyrate (GABA) accumulates in various plant parts, including bulky fruits such as apples, in response to abiotic stress. It is generally believed that the GABA is derived from glutamate, although a contribution from polyamines is possible. Putrescine, but not spermidine and spermine, generally accumulates in response to the genetic manipulation of polyamine biosynthetic enzymes and abiotic stress. However, the GABA levels in stressed plants are influenced by processes other than putrescine availability. It is hypothesized that the catabolism of putrescine to GABA is regulated by a combination of gene-dependent and -independent processes. The expression of several putative diamine oxidase genes is weak, but highly stress-inducible in certain tissues of Arabidopsis. In contrast, candidate genes that encode 4-aminobutyraldehyde dehydrogenase are highly constitutive, but not stress inducible. Changes in O(2) availability and cellular redox balance due to stress may directly influence the activities of diamine oxidase and 4-aminobutyraldehyde dehydrogenase, thereby restricting GABA formation. Apple fruit is known to accumulate GABA under controlled atmosphere storage and therefore could serve as a model system for investigating the relative contribution of putrescine and glutamate to GABA production.

  2. Expression of miRNAs confers enhanced tolerance to drought and salt stress in Finger millet (Eleusine coracona

    Directory of Open Access Journals (Sweden)

    Nageshbabu R.

    2013-08-01

    Full Text Available Plants respond to the environmental cues in various ways, recent knowledge of RNA interference in conferring stress tolerance had become a new hope of developing tolerant varieties. Here we attempt to unfold the molecular mechanism of stress tolerance through miRNA profiling and expression analysis in Finger millet (Eleusine coracona under salt and drought stress conditions. The expression analysis of 12 stress specific conserved miRNAs was studied using semi-quantitative real time PCR and Northern blot assay. Our studies revealed that, although most of the miRNAs responded to the stresses, the expression of particular miRNA differed with the nature of stress and the tissue. The expression analysis was correlated with the existing data of their target genes. Abiotic stress up-regulated miRNAs are expected to target negative regulators of stress responses or positive regulators of processes that are inhibited by stresses. On the other hand, stress down-regulated miRNAs may repress the expression of positive regulators and/or stress up-regulated genes. Thus the current study of miRNAs and their targets under abiotic stress conditions displays miRNAs may be good candidates to attribute the stress tolerance in plants by transgenic technology.

  3. Silencing of TaBTF3 gene impairs tolerance to freezing and drought stresses in wheat.

    Science.gov (United States)

    Kang, Guozhang; Ma, Hongzhen; Liu, Guoqin; Han, Qiaoxia; Li, Chengwei; Guo, Tiancai

    2013-11-01

    Basic transcription factor 3 (BTF3), the β-subunit of the nascent polypeptide-associated complex, is responsible for the transcriptional initiation of RNA polymerase II and is also involved in cell apoptosis, translation initiation regulation, growth, development, and other functions. Here, we report the impact of BTF3 on abiotic tolerance in higher plants. The transcription levels of the TaBTF3 gene, first isolated from wheat seedlings in our lab, were differentially regulated by diverse abiotic stresses and hormone treatments, including PEG-induced stress (20 % polyethylene glycol 6000), cold (4 °C), salt (100 mM NaCl), abscisic acid (100 μM), methyl jasmonate (50 μM), and salicylic acid (50 μM). Southern blot analysis indicated that, in the wheat genome, TaBTF3 is a multi-copy gene. Compared to BSMV-GFP-infected wheat plants (control), under freezing (-8 °C for 48 h) or drought stress (withholding water for 15 days) conditions, TaBTF3-silenced wheat plants showed lower survival rates, free proline content, and relative water content and higher relative electrical conductivity and water loss rate. These results suggest that silencing of the TaBTF3 gene may impair tolerance to freezing and drought stresses in wheat and that it may be involved in the response to abiotic stresses in higher plants.

  4. The 6-phosphogluconate Dehydrogenase Genes Are Responsive to Abiotic Stresses in Rice

    Institute of Scientific and Technical Information of China (English)

    Fu-Yun Hou; Ji Huang; Shan-Lin Yu; Hong-Sheng Zhang

    2007-01-01

    Glucose-6-phosphate dehydrogenase (G6PDH, E.C. 1.1.1.49) and 6-phosphogluconate dehydrogenase (6PGDH, EC 1.1.1.44) are both key enzymes of the pentose phosphate pathway (PPP). The OsG6PDH1 and Os6PGDH1 genes encoding cytosolic G6PDH and cytosolic 6PGDH were isoiated from rice (Oryza satlva L.). We have shown that Os6PGDH1 gene was up-regulated by salt stress. Here we reported the isolation and characterization of Os6PGDH2 from rice, which encode the plastidic counterpart of 6PGDH. Genomic organization analysis indicated that OsG6PDH1 and OsG6PDH2 genes contain multiple introns, whereas two Os6PGDH1 and Os6PGDH2 genes have no introns in their translated regions. In a step towards understanding the functions of the pentose phosphate pathway in plants in response to various abiotic stresses, the expressions of four genes in the rice seedlings treated by drought, cold, high salinity and abscisic acid (ABA) were investigated. The results show that OsG6PDH1 and OsG6PDH2 are not markedly regulated by the abiotic stresses detected. However, the transcript levels of both Os6PGDH1 and Os6PGDH2 are up-regulated in rice seedlings under drought, cold, high salinity and ABA treatments. Meanwhile,the enzyme activities of G6PDH and 6PGDH in the rice seedlings treated by various ablotlc stresses were investigated.Like the mRNA expression patterns, G6PDH activity remains constant but the 6PGDH increases steadily during the treatments. Taken together, we suggest that the pentose phosphate pathway may play an important role in rice responses to abiotlc stresses and the second key enzyme of PPP, 6PGDH, may function as a regulator controlling the efficiency of the pathway under abiotic stresses.

  5. Stress-tolerant P-solubilizing microorganisms.

    Science.gov (United States)

    Vassilev, N; Eichler-Löbermann, B; Vassileva, M

    2012-08-01

    Drought, high/low temperature, and salinity are abiotic stress factors accepted as the main reason for crop yield losses in a world with growing population and food price increases. Additional problems create nutrient limitations and particularly low P soil status. The problem of phosphate fertilizers, P plant nutrition, and existing phosphate bearing resources can also be related to the scarcity of rock phosphate. The modern agricultural systems are highly dependent on the existing fertilizer industry based exclusively of this natural, finite, non-renewable resource. Biotechnology offers a number of sustainable solutions that can mitigate these problems by using plant beneficial, including P-solubilizing, microorganisms. This short review paper summarizes the current and future trends in isolation, development, and application of P-solubilizing microorganisms in stress environmental conditions bearing also in mind the imbalanced cycling and unsustainable management of P. Special attention is devoted to the efforts on development of biotechnological strategies for formulation of P-solubilizing microorganisms in order to increase their protection against adverse abiotic factors.

  6. Foxtail millet NF-Y families: genome-wide survey and evolution analyses identified two functional genes important in abiotic stresses

    Directory of Open Access Journals (Sweden)

    Zhi-Juan eFeng

    2015-12-01

    Full Text Available It was reported that Nuclear Factor Y (NF-Y genes were involved in abiotic stress in plants. Foxtail millet (Setaria italica, an elite stress tolerant crop, provided an impetus for the investigation of the NF-Y families in abiotic responses. In the present study, a total of 39 NF-Y genes were identified in foxtail millet. Synteny analyses suggested that foxtail millet NF-Y genes had experienced rapid expansion and strong purifying selection during the process of plant evolution. De novo transcriptome assembly of foxtail millet revealed 11 drought up-regulated NF-Y genes. SiNF-YA1 and SiNF-YB8 were highly activated in leaves and/or roots by drought and salt stresses. Abscisic acid (ABA and H2O2 played positive roles in the induction of SiNF-YA1 and SiNF-YB8 under stress treatments. Transient luciferase (LUC expression assays revealed that SiNF-YA1 and SiNF-YB8 could activate the LUC gene driven by the tobacco (Nicotiana tobacam NtERD10, NtLEA5, NtCAT, NtSOD or NtPOD promoter under normal or stress conditions. Overexpression of SiNF-YA1 enhanced drought and salt tolerance by activating stress-related genes NtERD10 and NtCAT1 and by maintaining relatively stable relative water content (RWC and contents of chlorophyll, superoxide dismutase (SOD, peroxidase (POD, catalase (CAT and malondialdehyde (MDA in transgenic lines under stresses. SiNF-YB8 regulated expression of NtSOD, NtPOD, NtLEA5 and NtERD10 and conferred relatively high RWC and chlorophyll contents and low MDA content, resulting in drought and osmotic tolerance in transgenic lines under stresses. Therefore, SiNF-YA1 and SiNF-YB8 could activate stress-related genes and improve physiological traits, resulting in tolerance to abiotic stresses in plants. All these results will facilitate functional characterization of foxtail millet NF-Ys in future studies.

  7. Foxtail Millet NF-Y Families: Genome-Wide Survey and Evolution Analyses Identified Two Functional Genes Important in Abiotic Stresses.

    Science.gov (United States)

    Feng, Zhi-Juan; He, Guan-Hua; Zheng, Wei-Jun; Lu, Pan-Pan; Chen, Ming; Gong, Ya-Ming; Ma, You-Zhi; Xu, Zhao-Shi

    2015-01-01

    It was reported that Nuclear Factor Y (NF-Y) genes were involved in abiotic stress in plants. Foxtail millet (Setaria italica), an elite stress tolerant crop, provided an impetus for the investigation of the NF-Y families in abiotic responses. In the present study, a total of 39 NF-Y genes were identified in foxtail millet. Synteny analyses suggested that foxtail millet NF-Y genes had experienced rapid expansion and strong purifying selection during the process of plant evolution. De novo transcriptome assembly of foxtail millet revealed 11 drought up-regulated NF-Y genes. SiNF-YA1 and SiNF-YB8 were highly activated in leaves and/or roots by drought and salt stresses. Abscisic acid (ABA) and H2O2 played positive roles in the induction of SiNF-YA1 and SiNF-YB8 under stress treatments. Transient luciferase (LUC) expression assays revealed that SiNF-YA1 and SiNF-YB8 could activate the LUC gene driven by the tobacco (Nicotiana tobacam) NtERD10, NtLEA5, NtCAT, NtSOD, or NtPOD promoter under normal or stress conditions. Overexpression of SiNF-YA1 enhanced drought and salt tolerance by activating stress-related genes NtERD10 and NtCAT1 and by maintaining relatively stable relative water content (RWC) and contents of chlorophyll, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and malondialdehyde (MDA) in transgenic lines under stresses. SiNF-YB8 regulated expression of NtSOD, NtPOD, NtLEA5, and NtERD10 and conferred relatively high RWC and chlorophyll contents and low MDA content, resulting in drought and osmotic tolerance in transgenic lines under stresses. Therefore, SiNF-YA1 and SiNF-YB8 could activate stress-related genes and improve physiological traits, resulting in tolerance to abiotic stresses in plants. All these results will facilitate functional characterization of foxtail millet NF-Ys in future studies.

  8. Cullin-RING Ubiquitin Ligase Family in Plant Abiotic Stress Pathways

    Institute of Scientific and Technical Information of China (English)

    Liquan Guo; Cynthia D.Nezames; Lianxi Sheng; Xingwang Deng; Ning Wei

    2013-01-01

    The ubiquitin-proteasome system is a key mechanism that plants use to generate adaptive responses in coping with various environmental stresses.Cullin-RING (CRL) complexes represent a predominant group of ubiquitin E3 ligases in this system.In this review,we focus on the CRL E3s that have been implicated in abiotic stress signaling pathways in Arabidopsis.By comparing and analyzing these cases,we hope to gain a better understanding on how CRL complexes work under various settings in an attempt to decipher the clues about the regulatory mechanism of CRL E3s.

  9. Semiochemicals from ex situ abiotically stressed cactus tissue: a contributing role of fungal spores?

    Science.gov (United States)

    Beck, John J; Baig, Nausheena; Cook, Daniel; Mahoney, Noreen E; Marsico, Travis D

    2014-12-24

    Semiochemicals play a central role in communication between plants and insects, such as signaling the location of a suitable host. Fungi on host plants can also play an influential role in communicating certain plant vulnerabilities to an insect. The spiroketal conophthorin is an important semiochemical produced by developing fungal spores. Spiroketals are also used as signals for scolytid communication. Plants and fungi are known to emit varying volatile profiles under biotic and abiotic stress. This paper reports distinctive temporal-volatile profiles from three abiotic treatments, room temperature (control), -15 °C (cold), and -15 °C to room temperature (shock), of cactus tissue plugs. Volatiles from the three treatments included monoterpenes from control plugs, compounds of varying classes and origin at later stages for cold plugs, and known semiochemicals, including spiroketals, at later stages for shock plugs. The results highlight several important findings: a unique tissue source of the spiroketals; abiotic cold-shock stress is indicated as the cause of spiroketal production; and, given previous findings of spirogenesis, fungal spore involvement is a probable biosynthetic origin of the spiroketals. These findings suggest an important role of fungal volatiles as signaling plant vulnerability to insects.

  10. Transcription factors as tools to engineer enhanced drought stress tolerance in plants.

    Science.gov (United States)

    Hussain, Syed Sarfraz; Kayani, Mahmood Akhtar; Amjad, Muhammad

    2011-01-01

    Plant growth and productivity are greatly affected by abiotic stresses such as drought, salinity, and temperature. Drought stress is one of the major limitations to crop productivity worldwide due to its multigene nature, making the production of transgenic crops a challenging prospect. To develop crop plant with enhanced tolerance of drought stress, a basic understanding of physiological, biochemical, and gene regulatory networks is essential. In the signal transduction network that leads from the perception of stress signals to the expression of stress-responsive genes, transcription factors (TFs) play an essential role. Because TFs, as opposed to most structural genes, tend to control multiple pathways steps, they have emerged as powerful tools for the manipulation of complex metabolic pathways in plants. One such class of TFs is DREB/CBF that binds to drought responsive cis-acting elements. Transgenic plants have been developed with enhanced stress tolerance by manipulating the expression of DREB/CBF. Recently the functions of an increasing number of plant TFs are being elucidated and increased understanding of these factors in controlling drought stress response has lead to practical approaches for engineering stress tolerance in plants. The utility of the various TFs in plant stress research we review is illustrated by several published examples. The manipulation of native plant regularity networks therefore represents a new era for genetically modified crops. This review focuses on the recent understanding, latest advancements related to TFs and present status of their deployment in developing stress tolerant transgenic plants.

  11. Functional characterization of Arabidopsis NaCl-inducible WRKY25 and WRKY33 transcription factors in abiotic stresses.

    Science.gov (United States)

    Jiang, Yuanqing; Deyholos, Michael K

    2009-01-01

    Previous microarray analyses of Arabidopsis roots identified two closely related WRKY transcription factors (WRKY25 and WRKY33) among the transcripts that increased in abundance following treatment with NaCl. Here, we report further characterization of these genes, which we found to be inducible by a variety of abiotic stresses in an SOS-pathway independent manner, although WRKY33 induction was dependent on ABA signaling. Transcripts of both genes were detected in roots and leaves, while specific patterns of enrichment were observed in stems and floral buds for WRKY25 and WRKY33, respectively. We also identified upstream intergenic regions from each gene that were sufficient to confer stress-inducible expression on a reporter gene. However, the stress sensitivity of wrky25 null mutants did not differ from wild-type under any assay condition, while wrky33 null mutants and wrky25wrky33 double mutants showed only a moderate increase in NaCl-sensitivity, suggesting functional redundancy with other transcription factors. Nevertheless, overexpression of WRKY25 or WRKY33 was sufficient to increase Arabidopsis NaCl tolerance, while increasing sensitivity to ABA. Through microarray analyses of relevant genotypes, we identified 31 and 208 potential downstream targets of WRKY25 and WRKY33, respectively, most of which contained a W-box in their upstream regions.

  12. Tetraploid citrus rootstocks are more tolerant to salt stress than diploid.

    Science.gov (United States)

    Saleh, Basel; Allario, Thierry; Dambier, Dominique; Ollitrault, Patrick; Morillon, Raphaël

    2008-09-01

    Citrus trees are subject to several abiotic constraints such as salinity. Providing new rootstocks more tolerant is thus a requirement. In this article, we investigated salt stress tolerance of three tetraploid rootstock genotypes when compared to their respective diploid rootstocks (Poncirus trifoliata, Carrizo citrange, Cleopatra mandarin). Plant growth, leaf fall and ion contents were investigated. At the end of the experiment, leaf fall was observed only for diploid Poncirus trifoliata plants as well as chlorosis symptoms for Poncirus trifoliata and Carrizo citrange diploid plants. The diploid Cleopatra mandarin plants growth rate was not affected by salt stress and has even been increased for tetraploid Cleopatra mandarin. Ion contents investigation has shown lower accumulations of chloride ions in leaves of the tetraploid plants when compared to diploid plants. Our results suggest that citrus tetraploid rootstocks are more tolerant to salt stress than their corresponding diploid.

  13. The Native Plasmid pML21 Plays a Role in Stress Tolerance in Enterococcus faecalis ML21, as Analyzed by Plasmid Curing Using Plasmid Incompatibility.

    Science.gov (United States)

    Zuo, Fang-Lei; Chen, Li-Li; Zeng, Zhu; Feng, Xiu-Juan; Yu, Rui; Lu, Xiao-Ming; Ma, Hui-Qin; Chen, Shang-Wu

    2016-02-01

    To investigate the role of the native plasmid pML21 in Enterococcus faecalis ML21's response to abiotic stresses, the plasmid pML21 was cured based on the principle of plasmid incompatibility and segregational instability, generating E. faecalis mutant strain ML0. The mutant and the wild strains were exposed to abiotic stresses: bile salts, low pH, H2O2, ethanol, heat, and NaCl, and their survival rate was measured. We found that curing of pML21 lead to reduced tolerance to stress in E. faecalis ML0, especially oxidative and osmotic stress. Complementation analysis suggested that the genes from pML21 played different role in stress tolerance. The result indicated that pML21 plays a role in E. faecalis ML21's response to abiotic stresses.

  14. Enhancing crop resilience to combined abiotic and biotic stress through the dissection of physiological and molecular crosstalk

    NARCIS (Netherlands)

    Kissoudis, C.; Wiel, van de C.C.M.; Visser, R.G.F.; Linden, van der C.G.

    2014-01-01

    Plants growing in their natural habitats are often challenged simultaneously by multiple stress factors, both abiotic and biotic. Research has so far been limited to responses to individual stresses, and understanding of adaptation to combinatorial stress is limited, but indicative of non-additive i

  15. Responses to combined abiotic and biotic stress in tomato are governed by stress intensity and resistance mechanism.

    Science.gov (United States)

    Kissoudis, Christos; Sunarti, Sri; van de Wiel, Clemens; Visser, Richard G F; van der Linden, C Gerard; Bai, Yuling

    2016-09-01

    Stress conditions in agricultural ecosystems can occur at variable intensities. Different resistance mechanisms against abiotic stress and pathogens are deployed by plants. Thus, it is important to examine plant responses to stress combinations under different scenarios. Here, we evaluated the effect of different levels of salt stress ranging from mild to severe (50, 100, and 150mM NaCl) on powdery mildew resistance and overall performance of tomato introgression lines with contrasting levels of partial resistance, as well as near-isogenic lines (NILs) carrying the resistance gene Ol-1 (associated with a slow hypersensitivity response; HR), ol-2 (an mlo mutant associated with papilla formation), and Ol-4 (an R gene associated with a fast HR). Powdery mildew resistance was affected by salt stress in a genotype- and stress intensity-dependent manner. In susceptible and partial resistant lines, increased susceptibility was observed under mild salt stress (50mM) which was accompanied by accelerated cell death-like senescence. In contrast, severe salt stress (150mM) reduced disease symptoms. Na(+) and Cl(-) accumulation in the leaves was linearly related to the decreased pathogen symptoms under severe stress. In contrast, complete resistance mediated by ol-2 and Ol-4 was unaffected under all treatment combinations, and was associated with a decreased growth penalty. Increased susceptibility and senescence under combined stress in NIL-Ol-1 was associated with the induction of ethylene and jasmonic acid pathway genes and the cell wall invertase gene LIN6. These results highlight the significance of stress severity and resistance type on the plant's performance under the combination of abiotic and biotic stress.

  16. Molecular Analysis of Rice CIPKs Involved in Both Biotic and Abiotic Stress Responses

    Institute of Scientific and Technical Information of China (English)

    CHEN Xi-feng; Gu Zhi-min; LIU Feng; MA Bo-jun; ZHANG Hong-sheng

    2011-01-01

    Plant calcineurin B-like (CBL) proteins have been proposed as important Ca2+ sensors and specifically interact with CBL-interacting protein kinases (CIPKs) in plant-specific calcium signaling.Here,we identified and isolated 15 CIPK genes in a japonica rice variety Nipponbare based on the predicted sequences of rice CIPK gene family.Gene structure analysis showed that these 15 genes were divided into intron-less and intron-rich groups,and OsCIPK3 and OsCIPK24 exhibited alternative splicing in their mature process.The phylogenetic analyses indicated that rice CIPKs shared an ancestor with Arabidopsis and poplar CIPKs.Analyses of gene expression showed that these OsCIPK genes were differentially induced by biotic stresses such as bacterial blight and abiotic stresses (heavy metal such as Hg2+,high salinity,cold and ABA).Interestingly,five OsCIPK genes,OsCIPK1,2,10,11 and 12,were transcriptionally up-regulated after bacterial blight infection whereas four OsCIPK genes,OsCIPK2,10,11 and 14,were induced by all treatments,indicating that some of OsCIPK genes are involved in multiple stress response pathways in plants.Our finding suggests that CIPKs play a key role in both biotic and abiotic stress responses.

  17. Development of abiotic-stress resistant warm season trufgrasses by proton-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Y. W.; Kim, J. Y.; Jeong, S. H. [Korea Univ., Seoul (Korea, Republic of)

    2007-04-15

    The direct use of mutation is a valuable approach to generate genetic variation in crop species by altering agronomically useful major traits. The proton beam, as a mutagen, was applied to improve resistance traits of Zoysia grass under various abiotic stresses. Proton beam was irradiated to mature dry seeds of Zenith (Zoysia grass), which is well-adapted to Korean climate, using a proton- accelerator with seven different doses (50, 100, 150, 200, 250, 300, 400 Gy). Individual seedling of M1 plant was transplanted from the seed bed and allowed to reach appropriate plant mass. Clones that showed superior growth were chosen and transplanted to pots for further clone propagation and field evaluation. Growth characteristics of turfgrass, such as plant height, leaf length, leaf width, number of tiller were evaluated ninety days after sowing. Although large variation within each dose, noticeable differences were found among different irradiated doses. Most of the mutant clones derived from the irradiation treatment showed more vigorous growth than the control plants. RAPD (Random Amplified Polymorphic DNA) and AFLP (Amplified Fragment Length Polymorphism) methods were conducted to analyze genomic variations associated with proton beam irradiation. In order to establish selection criteria for selection of salt-stress resistance plants, an in vitro method that is able to select salt-stress resistant mutants in liquid media without ambient disturbances. Total 647 predominance clones that were considered as abiotic stress resistant mutants were transplanted to the field for further evaluation.

  18. Exophiala sp. LHL08 reprograms Cucumis sativus to higher growth under abiotic stresses.

    Science.gov (United States)

    Khan, Abdul L; Hamayun, Muhammad; Ahmad, Nadeem; Waqas, Muhammad; Kang, Sang-Mo; Kim, Yoon-Ha; Lee, In-Jung

    2011-12-01

    Endophytic fungi are potential sources of secondary metabolites; however, they are little known for phytohormones secretion and amelioration of plant growth under abiotic stresses. We isolated a novel endophyte from the roots of Cucumis sativus and identified it as a strain of Exophiala sp. by sequencing internal transcribed spacer/large subunit rDNA and phylogenetic analysis. Prior to identification, culture filtrate (CF) of Exophiala sp. has shown significant growth promotion of Waito-C [a gibberellins (GAs)-deficient mutant cultivar] and Dongjin-byeo (normal GAs biosynthesis cultivar) rice seedlings. CF analysis of Exophiala sp. showed the presence of physiologically active GAs (GA₁, GA₃, GA₄ and GA₇) and inactive GAs (GA₅, GA₈, GA₉, GA₁₂ and GA₂₀). Exophiala sp. had higher GAs in its CF than wild-type strain of Gibberella fujikuroi except GA₃. Influence of Exophiala sp. was assessed on cucumber plant's growth and endogenous abscisic acid (ABA), salicylic acid (SA) and bioactive GAs under salinity and drought stresses. Exophiala sp.-treated plants have shown significantly higher growth and rescued the host plants from stress promulgated water deficit, osmotic and cellular damage. The altered levels of stress-responsive ABA showed low level of stress confined to endophyte-applied plants than control. Elevated levels of SA and bioactive GAs (GA₃ and GA₄) in endophyte-associated plants suggest stress-modulating response toward salinity and drought. In conclusion, symbiotic relations between Exophiala and cucumber have reprogrammed the host plant growth under abiotic stresses, thus indicating a possible threshold role of endophytic fungi in stress alleviation. This study could be extended for improving agricultural productivity under extreme environmental conditions.

  19. Improved Growth and Stress Tolerance in the Arabidopsis oxt1 Mutant Triggered by Altered Adenine Metabolism

    Institute of Scientific and Technical Information of China (English)

    Suchada Sukrong; Kil-Young Yun; Patrizia Stadler; Charan Kumar; Tony Facciuolo; Barbara A.Moffatt; Deane L.Falcone

    2012-01-01

    Plants perceive and respond to environmental stresses with complex mechanisms that are often associated with the activation of antioxidant defenses.A genetic screen aimed at isolating oxidative stress-tolerant lines of Arabidopsis thaliana has identified oxt1,a line that exhibits improved tolerance to oxidative stress and elevated temperature but displays no apparent deleterious growth effects under non-stress conditions.Oxt1 harbors a mutation that arises from the altered expression of a gene encoding adenine phosphoribosyltransferase (APT1),an enzyme that converts adenine to adenosine monophosphate (AMP),indicating a link between purine metabolism,whole-plant growth responses,and stress acclimation.The oxt1 mutation results in decreased APT1 expression that leads to reduced enzymatic activity.Correspondingly,oxt1 plants possess elevated levels of adenine.Decreased APT enzyme activity directly correlates with stress resistance in transgenic lines that ectopically express APT1.The metabolic alteration in oxt1 plants also alters the expression of several antioxidant defense genes and the response of these genes to oxidative challenge.Finally,it is shown that manipulation of adenine levels can induce stress tolerance to wild-type plants.Collectively,these results show that alterations in cellular adenine levels can trigger stress tolerance and improve growth,leading to increases in plant biomass.The results also suggest that adenine might play a part in the signals that modulate responses to abiotic stress and plant growth.

  20. Putrescine, a fast-acting switch for tolerance against osmotic stress.

    Science.gov (United States)

    Kotakis, Christos; Theodoropoulou, Eleftheria; Tassis, Konstantinos; Oustamanolakis, Charalambos; Ioannidis, Nikolaos E; Kotzabasis, Kiriakos

    2014-01-15

    During the last decade we showed clearly that abiotic stress changes the cellular composition of polyamines, which in turn regulate the photochemical and non-photochemical quenching of the received light energy in the photosynthetic apparatus and that modulate substantially the level of plant tolerance. In the present contribution, we tried to change the bioenergetics of the leaf discs before the exposure to osmotic stress only by exogenously supplied putrescine, in order to enhance quickly the tolerance against the abiotic stress. Tobacco leaf discs treated with polyethylene-glycol reduced their water content about 24% within 1h. This relatively mild osmotic stress increased endogenous putrescine about 83% and decreased maximum photosystem II photochemical efficiency about 14%. In line with this, here we show that treatment with 1mM exogenous putrescine 1h before polyethylene-glycol addition protects the photochemical capacity and inhibits loss of water, confirming the key role of putrescine in the modulation of plant tolerance against osmotic stress. Furthermore, our recent works indicate that putrescine is accumulated in lumen during light reactions and may act as a permeable buffer and an osmolyte.

  1. A membrane-bound NAC transcription factor as an integrator of biotic and abiotic stress signals.

    Science.gov (United States)

    Seo, Pil Joon; Park, Chung-Mo

    2010-05-01

    Transcription factors are central components of gene regulatory networks that mediate virtually all aspects of growth and developmental processes in biological systems. The activity of transcription factors is regulated at multiple steps, such as gene transcription, posttranscriptional RNA processing, posttranslational modification, protein-protein interactions, and controlled protein turnover. Controlled activation of dormant, membrane-bound transcription factor (MTF) is an intriguing regulatory mechanism that ensures quick transcriptional responses to environmental fluctuations in plants, in which various stress hormones serve as signaling mediators. NTL6 is proteolytically activated upon exposure to cold and induces expression of the Pathogenesis-Related (PR) genes. The membrane-mediated cold signaling in inducing pathogen resistance is considered to be an adaptive strategy that protects plants against infection by hydrophilic pathogens frequently occurring during cold season. We found that NTL6 also mediates abscisic acid (ABA) regulation of abiotic stress responses in Arabidopsis. NTL6 is proteolytically activated by ABA. Transgenic plants overexpressing a nuclear NTL6 form (35S:6ΔC) exhibited a hypersensitive response to ABA and high salinity in seed germination. Taken together, these observations indicate that NTL6 plays an integrative role in plant responses to both biotic and abiotic stress conditions.

  2. Quantitative changes of secondary metabolites of Matricaria chamomilla by abiotic stress.

    Science.gov (United States)

    Eliasová, Adriana; Repcák, Miroslav; Pastírová, Andrea

    2004-01-01

    The responses of young plants of diploid and tetraploid Matricaria chamomilla cultivars to abiotic stress were studied. The course of quantitative changes of main leaf secondary metabolites was evaluated within an interval from 6 h before to 54 h after spraying the leaf rosettes with aqueous CuCl2 solution. The content of herniarin in the treated plants rose approximately 3 times, simultaneously with a decline of its precursor (Z)- and (E)-2-beta-D-glucopyranosyloxy-4-methoxycinnamic acid. The highest amounts of umbelliferone in stressed plants exceeded 9 times and 20 times those observed in control plants of the tetraploid and diploid cultivar, respectively. Due to stress the concentration of ene-yne-dicycloether in leaves decreased by more than 40%. The pattern of quantity changes of the examined compounds in tetraploid and diploid plants was similar.

  3. Transplastomic Nicotiana benthamiana plants expressing multiple defence genes encoding protease inhibitors and chitinase display broad-spectrum resistance against insects, pathogens and abiotic stresses.

    Science.gov (United States)

    Chen, Peng-Jen; Senthilkumar, Rajendran; Jane, Wann-Neng; He, Yong; Tian, Zhihong; Yeh, Kai-Wun

    2014-05-01

    Plastid engineering provides several advantages for the next generation of transgenic technology, including the convenient use of transgene stacking and the generation of high expression levels of foreign proteins. With the goal of generating transplastomic plants with multiresistance against both phytopathogens and insects, a construct containing a monocistronic patterned gene stack was transformed into Nicotiana benthamiana plastids harbouring sweet potato sporamin, taro cystatin and chitinase from Paecilomyces javanicus. Transplastomic lines were screened and characterized by Southern/Northern/Western blot analysis for the confirmation of transgene integration and respective expression level. Immunogold localization analyses confirmed the high level of accumulation proteins that were specifically expressed in leaf and root plastids. Subsequent functional bioassays confirmed that the gene stacks conferred a high level of resistance against both insects and phytopathogens. Specifically, larva of Spodoptera litura and Spodoptera exigua either died or exhibited growth retardation after ingesting transplastomic plant leaves. In addition, the inhibitory effects on both leaf spot diseases caused by Alternaria alternata and soft rot disease caused by Pectobacterium carotovorum subsp. carotovorum were markedly observed. Moreover, tolerance to abiotic stresses such as salt/osmotic stress was highly enhanced. The results confirmed that the simultaneous expression of sporamin, cystatin and chitinase conferred a broad spectrum of resistance. Conversely, the expression of single transgenes was not capable of conferring such resistance. To the best of our knowledge, this is the first study to demonstrate an efficacious stacked combination of plastid-expressed defence genes which resulted in an engineered tolerance to various abiotic and biotic stresses.

  4. Isolation of a novel peroxisomal catalase gene from sugarcane, which is responsive to biotic and abiotic stresses.

    Directory of Open Access Journals (Sweden)

    Yachun Su

    Full Text Available Catalase is an iron porphyrin enzyme, which serves as an efficient scavenger of reactive oxygen species (ROS to avoid oxidative damage. In sugarcane, the enzymatic activity of catalase in a variety (Yacheng05-179 resistant to the smut pathogen Sporisorium scitamineum was always higher than that of the susceptible variety (Liucheng03-182, suggesting that catalase activity may have a positive correlation with smut resistance in sugarcane. To understand the function of catalase at the molecular level, a cDNA sequence of ScCAT1 (GenBank Accession No. KF664183, was isolated from sugarcane infected by S. scitamineum. ScCAT1 was predicted to encode 492 amino acid residues, and its deduced amino acid sequence shared a high degree of homology with other plant catalases. Enhanced growth of ScCAT1 in recombinant Escherichia coli Rosetta cells under the stresses of CuCl2, CdCl2 and NaCl indicated its high tolerance. Q-PCR results showed that ScCAT1 was expressed at relatively high levels in the bud, whereas expression was moderate in stem epidermis and stem pith. Different kinds of stresses, including S. scitamineum challenge, plant hormones (SA, MeJA and ABA treatments, oxidative (H2O2 stress, heavy metal (CuCl2 and hyper-osmotic (PEG and NaCl stresses, triggered a significant induction of ScCAT1. The ScCAT1 protein appeared to localize in plasma membrane and cytoplasm. Furthermore, histochemical assays using DAB and trypan blue staining, as well as conductivity measurement, indicated that ScCAT1 may confer the sugarcane immunity. In conclusion, the positive response of ScCAT1 to biotic and abiotic stresses suggests that ScCAT1 is involved in protection of sugarcane against reactive oxidant-related environmental stimuli.

  5. Stress-inducible expression of barley Hva1 gene in transgenic mulberry displays enhanced tolerance against drought, salinity and cold stress.

    Science.gov (United States)

    Checker, Vibha G; Chhibbar, Anju K; Khurana, Paramjit

    2012-10-01

    Coping with different kinds of biotic and abiotic stresses is the foundation of sustainable agriculture. Although conventional breeding and marker-assisted selection are being employed in mulberry (Morus indica L.) to develop better varieties, nonetheless the longer time periods required for these approaches necessitates the use of precise biotechnological approaches for sustainable agriculture. In an attempt to improve stress tolerance of mulberry, an important plant of the sericulture industry, an encoding late embryogenesis abundant gene from barley (HVA1) was introduced into mulberry plants by Agrobacterium-mediated transformation. Transgenic mulberry with barley Hva1 under a constitutive promoter actin1 was shown to enhance drought and salinity tolerance. Here, we report that overexpression of barley Hva1 also confers cold tolerance in transgenic mulberry. Further, barley Hva1 gene under control of a stress-inducible promoter rd29A can effectively negate growth retardation under non-stress conditions and confer stress tolerance in transgenic mulberry. Transgenic lines display normal morphology to enhanced growth and an increased tolerance against drought, salt and cold conditions as measured by free proline, membrane stability index and PSII activity. Protein accumulation was detected under stress conditions confirming inductive expression of HVA1 in transgenics. Investigations to assess stress tolerance of these plants under field conditions revealed an overall better performance than the non-transgenic plants. Enhanced expression of stress responsive genes such as Mi dnaJ and Mi 2-cysperoxidin suggests that Hva1 can regulate downstream genes associated with providing abiotic stress tolerance. The investigation of transgenic lines presented here demonstrates the acquisition of tolerance against drought, salt and cold stress in plants overexpressing barley Hva1, indicating that Arabidopsis rd29A promoter can function in mulberry.

  6. Identification and Characterization of Proteins Associated with Plant Tolerance to Heat Stress

    Institute of Scientific and Technical Information of China (English)

    Bingru Huang; Chenping Xu

    2008-01-01

    Heat stress is a major abiotic stress limiting plant growth and productivity in many areas of the world. Understanding mechanisms of plant adaptation to heat stress would facilitate the development of heat-tolerant cultivars for improving productivity in warm climatic regions. Protein metabolism involving protein synthesis and degradation is one of the most sensitive processes to heat stress. Changes in the level and expression pattern of some proteins may play an important role in plant adaptation to heat stress. The identification of stress-responsive proteins and pathways has been facilitated by an increasing number of tools and resources, including two-dimensional electrophoresis and mass spectrometry, and the rapidly expanding nucleotide and amino acid sequence databases. Heat stress may induce or enhance protein expression or cause protein degradation. The induction of heat-responsive proteins, particularly heat shock proteins (HSPs), plays a key role in plant tolerance to heat stress. Protein degradation involving various proteases is also important in regulating plant responses to heat stress. This review provides an overview of recent research on proteomic profiling for the identification of heat-responsive proteins associated with heat tolerance, heat induction and characteristics of HSPs, and protein degradation in relation to plant responses to heat stress.

  7. Heterologous expression of Anabaena PCC 7120 all3940 (a Dps family gene) protects Escherichia coli from nutrient limitation and abiotic stresses

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Om Prakash; Kumari, Nidhi [Molecular Biology Section, Laboratory of Algal Biology, Center of Advanced Study in Botany, Banaras Hindu University, Varanasi-22 1005 (India); Rai, Lal Chand, E-mail: lcraibhu@gmail.com [Molecular Biology Section, Laboratory of Algal Biology, Center of Advanced Study in Botany, Banaras Hindu University, Varanasi-22 1005 (India)

    2010-03-26

    This study presents first hand data on the cloning and heterologous expression of Anabaena PCC 7120 all3940 (a dps family gene) in combating nutrients limitation and multiple abiotic stresses. The Escherichia coli transformed with pGEX-5X-2-all3940 construct when subjected to iron, carbon, nitrogen, phosphorus limitation and carbofuron, copper, UV-B, heat, salt and cadmium stress registered significant increase in growth over the cells transformed with empty vector under iron (0%), carbon (0.05%), nitrogen (3.7 mM) and phosphorus (2 mM) limitation and carbofuron (0.025 mg ml{sup -1}), CuCl{sub 2} (1 mM), UV-B (10 min), heat (47 {sup o}C), NaCl (6% w/v) and CdCl{sub 2} (4 mM) stress. Enhanced expression of all3940 gene measured by semi-quantitative RT-PCR at different time points under above mentioned treatments clearly demonstrates its role in tolerance against aforesaid abiotic stresses. This study opens the gate for developing transgenic cyanobacteria capable of growing successfully under above mentioned stresses.

  8. Comparative Expression Analysis of Two-Component System Members in Arabidopsis and Oryza sativa under Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Anupama eSingh

    2015-09-01

    Full Text Available Two component system (TCS is one of the key signal sensing machinery which enables species to sense environmental stimuli. It essentially comprises of three major components, sensory histidine kinase proteins (HKs, histidine phosphotransfer proteins (Hpts and response regulator proteins (RRs. The members of the TCS family have already been identified in Arabidopsis and rice but the knowledge about their functional indulgence during various abiotic stress conditions remains meagre. Current study is an attempt to carry out comprehensive analysis of the expression of TCS members in response to various abiotic stress conditions and in various plant tissues in Arabidopsis and rice using MPSS and publicly available microarray data. The analysis suggests that despite having almost similar number of genes, rice expresses higher number of TCS members during various abiotic stress conditions than Arabidopsis. We found that the TCS machinery is regulated by not only various abiotic stresses, but also by the tissue specificity. Analysis of expression of some representative members of TCS gene family showed their regulation by the diurnal cycle in rice seedlings, thus bringing-in another level of their transcriptional control. Thus, we report a highly complex and tight regulatory network of TCS members, as influenced by the tissue, abiotic stress signal and diurnal rhythm. The insights on the comparative expression analysis presented in this study may provide crucial leads towards dissection of diverse role(s of the various TCS family members in Arabidopsis and rice.

  9. Microarray: gateway to unravel the mystery of abiotic stresses in plants.

    Science.gov (United States)

    Gul, Ambreen; Ahad, Ammara; Akhtar, Sidra; Ahmad, Zarnab; Rashid, Bushra; Husnain, Tayyab

    2016-04-01

    Environmental factors, such as drought, salinity, extreme temperature, ozone poisoning, metal toxicity etc., significantly affect crops. To study these factors and to design a possible remedy, biological experimental data concerning these crops requires the quantification of gene expression and comparative analyses at high throughput level. Development of microarrays is the platform to study the differential expression profiling of the targeted genes. This technology can be applied to gene expression studies, ranging from individual genes to whole genome level. It is now possible to perform the quantification of the differential expression of genes on a glass slide in a single experiment. This review documents recently published reports on the use of microarrays for the identification of genes in different plant species playing their role in different cellular networks under abiotic stresses. The regulation pattern of differentially-expressed genes, individually or in group form, may help us to study different pathways and functions at the cellular and molecular level. These studies can provide us with a lot of useful information to unravel the mystery of abiotic stresses in important crop plants.

  10. The ATAF1 transcription factor: At the convergence point of ABA-dependent plant defense against biotic and abiotic stresses

    Institute of Scientific and Technical Information of China (English)

    Brigitte Mauch-Mani; Victor Flors

    2009-01-01

    @@ Because of their sessile lifestyle, plants have evolved sophisticated ways of coping with the various biotic and abiotic stresses they can encounter during their life. Their defensive reac-tions to a given stress have to be rapid and well adapted to the situation. They are the results of tightly coordinated changes at the molecular level involving the contributions of different signaling pathways.

  11. Biomass allocation and C-N-P stoichiometry in C3 and C4 crops under abiotic stress

    Science.gov (United States)

    Biomass allocation to structural, metabolic and reproductive organs as well as their carbon, nitrogen and phosphorus (C-N-P) profiles and ratios (C:N, C:P, and N:P) were estimated in C3 and C4 crop plants subjected to multiple abiotic stresses (i.e., combination of temperature and water stress level...

  12. Potentiality of Soybean Proteomics in Untying the Mechanism of Flood and Drought Stress Tolerance

    Directory of Open Access Journals (Sweden)

    Zahed Hossain

    2014-03-01

    Full Text Available Dissecting molecular pathways at protein level is essential for comprehensive understanding of plant stress response mechanism. Like other legume crops, soybean, the world’s most widely grown seed legume and an inexpensive source of protein and vegetable oil, is also extremely sensitive to abiotic stressors including flood and drought. Irrespective of the kind and severity of the water stress, soybean exhibits a tight control over the carbon metabolism to meet the cells required energy demand for alleviating stress effects. The present review summarizes the major proteomic findings related to changes in soybean proteomes in response to flood and drought stresses to get a clear insight into the complex mechanisms of stress tolerance. Furthermore, advantages and disadvantages of different protein extraction protocols and challenges and future prospects of soybean proteome study are discussed in detail to comprehend the underlying mechanism of water stress acclimation.

  13. Potentiality of Soybean Proteomics in Untying the Mechanism of Flood and Drought Stress Tolerance.

    Science.gov (United States)

    Hossain, Zahed; Komatsu, Setsuko

    2014-03-07

    Dissecting molecular pathways at protein level is essential for comprehensive understanding of plant stress response mechanism. Like other legume crops, soybean, the world's most widely grown seed legume and an inexpensive source of protein and vegetable oil, is also extremely sensitive to abiotic stressors including flood and drought. Irrespective of the kind and severity of the water stress, soybean exhibits a tight control over the carbon metabolism to meet the cells required energy demand for alleviating stress effects. The present review summarizes the major proteomic findings related to changes in soybean proteomes in response to flood and drought stresses to get a clear insight into the complex mechanisms of stress tolerance. Furthermore, advantages and disadvantages of different protein extraction protocols and challenges and future prospects of soybean proteome study are discussed in detail to comprehend the underlying mechanism of water stress acclimation.

  14. Changes in gene expression and catalase activity in Oryza sativa L. under abiotic stress.

    Science.gov (United States)

    Vighi, I L; Benitez, L C; do Amaral, M N; Auler, P A; Moraes, G P; Rodrigues, G S; da Maia, L C; Pinto, L S; Braga, E J B

    2016-11-03

    Different rice (Oryza sativa L.) genotypes were subjected to high salinity and low temperature (150 mM NaCl and 13°C, respectively) for 0, 6, 24, 48, or 72 h. We evaluated the simultaneous expression of the genes OsCATA, OsCATB, and OsCATC, correlated gene expression with enzyme activity, and verified the regulation of these genes through identification of cis-elements in the promoter region. The hydrogen peroxide content increased in a tolerant genotype and decreased in a sensitive genotype under both stress conditions. Lipid peroxidation increased in the tolerant genotype when exposed to cold, and in the sensitive genotype when exposed to high salinity. Catalase activity significantly increased in both genotypes when subjected to 13°C. In the tolerant genotype, OsCATA and OsCATB were the most responsive to high salinity and cold, while in the sensitive genotype, OsCATA and OsCATC responded positively to saline stress, as did OsCATA and OsCATB to low temperature. Cis-element analysis identified different regulatory sequences in the catalase promoter region of each genotype. The sensitive genotype maintained a better balance between hydrogen oxyacid levels, catalase activity, and lipid peroxidation under low temperature than the resistant genotype. OsCATA and OsCATB were the most responsive in the salt-tolerant genotype to cold, OsCATA and OsCATC were the most responsive to saline stress, and OsCATA and OsCATB were the most responsive to chilling stress in the sensitive genotype. There were positive correlations between catalase activity and OsCATB expression in the tolerant genotype under saline stress and in the sensitive genotype under cold stress.

  15. Influence of abiotic stress during soybean germination followed by recovery on the phenolic compounds of radicles and their antioxidant capacity

    Directory of Open Access Journals (Sweden)

    Sylwia Swigonska

    2014-09-01

    Full Text Available Abiotic stress factors are among the major causes of lower crop yields. It is known, that in response to cold and/or osmotic stress, crops activate various defense mechanisms, including morphological, physiological and metabolic adaptations. Secondary metabolism, especially phenolic compounds, seem to be an important factor of stress-induced metabolic re-engineering as their levels are alternated by abiotic stress in plants. Despite the fact, that the nature and function of phenolic compounds was already studied in various plant species, it is important to define tissue-specific changes induced by two most potent abiotic stressors – low temperature and decreased water potential. Moreover, in fields, the appearance of single stress is rather rare. Usually two or more factors are acting in parallel, which may potentially result in different effects. Therefore, the aim of this study was to analyze selected elements of secondary metabolism in roots of germinating soybean seeds under cold stress, osmotic stress and both stresses combined. In addition the effects of constant and persistent stress were compared to those induced by sudden and brief stress appearance, as well as after the post-stress recovery process. In the presented study standard methods for identification and quantification of phenolic acids and isoflavones were used and the antioxidant capacity of the radicle extracts was measured. The phenolic metabolism in plants was greatly intensified in response to cold and osmotic stress and remained at high level during the post-stress recovery. The amount and composition of both phenolic acids and identified isoflavones also changed in stress- and duration-dependent manner. This proves an important role of phenolic compounds in abiotic stress response of germinating soybean seeds and opens up new perspectives for further investigations.

  16. GmWRKY27 interacts with GmMYB174 to reduce expression of GmNAC29 for stress tolerance in soybean plants.

    Science.gov (United States)

    Wang, Fang; Chen, Hao-Wei; Li, Qing-Tian; Wei, Wei; Li, Wei; Zhang, Wan-Ke; Ma, Biao; Bi, Ying-Dong; Lai, Yong-Cai; Liu, Xin-Lei; Man, Wei-Qun; Zhang, Jin-Song; Chen, Shou-Yi

    2015-07-01

    Soybean (Glycine max) is an important crop for oil and protein resources worldwide. The molecular mechanism of the abiotic stress response in soybean is largely unclear. We previously identified multiple stress-responsive WRKY genes from soybean. Here, we further characterized the roles of one of these genes, GmWRKY27, in abiotic stress tolerance using a transgenic hairy root assay. GmWRKY27 expression was increased by various abiotic stresses. Over-expression and RNAi analysis demonstrated that GmWRKY27 improves salt and drought tolerance in transgenic soybean hairy roots. Measurement of physiological parameters, including reactive oxygen species and proline contents, supported this conclusion. GmWRKY27 inhibits expression of a downstream gene GmNAC29 by binding to the W-boxes in its promoter region. The GmNAC29 is a negative factor of stress tolerance as indicated by the performance of transgenic hairy roots under stress. GmWRKY27 interacts with GmMYB174, which also suppresses GmNAC29 expression and enhances drought stress tolerance. The GmWRKY27 and GmMYB174 may have evolved to bind to neighbouring cis elements in the GmNAC29 promoter to co-reduce promoter activity and gene expression. Our study discloses a valuable mechanism in soybean for regulation of the stress response by two associated transcription factors. Manipulation of these genes should facilitate improvements in stress tolerance in soybean and other crops.

  17. An Arabidopsis mitochondrial uncoupling protein confers tolerance to drought and salt stress in transgenic tobacco plants.

    Directory of Open Access Journals (Sweden)

    Kevin Begcy

    Full Text Available BACKGROUND: Plants are challenged by a large number of environmental stresses that reduce productivity and even cause death. Both chloroplasts and mitochondria produce reactive oxygen species under normal conditions; however, stress causes an imbalance in these species that leads to deviations from normal cellular conditions and a variety of toxic effects. Mitochondria have uncoupling proteins (UCPs that uncouple electron transport from ATP synthesis. There is evidence that UCPs play a role in alleviating stress caused by reactive oxygen species overproduction. However, direct evidence that UCPs protect plants from abiotic stress is lacking. METHODOLOGY/PRINCIPAL FINDINGS: Tolerances to salt and water deficit were analyzed in transgenic tobacco plants that overexpress a UCP (AtUCP1 from Arabidopsis thaliana. Seeds of AtUCP1 transgenic lines germinated faster, and adult plants showed better responses to drought and salt stress than wild-type (WT plants. These phenotypes correlated with increased water retention and higher gas exchange parameters in transgenic plants that overexpress AtUCP1. WT plants exhibited increased respiration under stress, while transgenic plants were only slightly affected. Furthermore, the transgenic plants showed reduced accumulation of hydrogen peroxide in stressed leaves compared with WT plants. CONCLUSIONS/SIGNIFICANCE: Higher levels of AtUCP1 improved tolerance to multiple abiotic stresses, and this protection was correlated with lower oxidative stress. Our data support previous assumptions that UCPs reduce the imbalance of reactive oxygen species. Our data also suggest that UCPs may play a role in stomatal closure, which agrees with other evidence of a direct relationship between these proteins and photosynthesis. Manipulation of the UCP protein expression in mitochondria is a new avenue for crop improvement and may lead to crops with greater tolerance for challenging environmental conditions.

  18. Analysis of Cell Wall-Related Genes in Organs of Medicago sativa L. under Different Abiotic Stresses.

    Science.gov (United States)

    Behr, Marc; Legay, Sylvain; Hausman, Jean-Francois; Guerriero, Gea

    2015-07-16

    Abiotic constraints are a source of concern in agriculture, because they can have a strong impact on plant growth and development, thereby affecting crop yield. The response of plants to abiotic constraints varies depending on the type of stress, on the species and on the organs. Although many studies have addressed different aspects of the plant response to abiotic stresses, only a handful has focused on the role of the cell wall. A targeted approach has been used here to study the expression of cell wall-related genes in different organs of alfalfa plants subjected for four days to three different abiotic stress treatments, namely salt, cold and heat stress. Genes involved in different steps of cell wall formation (cellulose biosynthesis, monolignol biosynthesis and polymerization) have been analyzed in different organs of Medicago sativa L. Prior to this analysis, an in silico classification of dirigent/dirigent-like proteins and class III peroxidases has been performed in Medicago truncatula and M. sativa. The final goal of this study is to infer and compare the expression patterns of cell wall-related genes in response to different abiotic stressors in the organs of an important legume crop.

  19. Arabidopsis LOS5 Gene Enhances Chilling and Salt Stress Tolerance in Cucumber

    Institute of Scientific and Technical Information of China (English)

    LIU Li-ying; DUAN Liu-sheng; ZHANG Jia-chang; MI Guo-quan; ZHANG Xiao-lan; ZHANG Zhen-xian; REN Hua-zhong

    2013-01-01

    Low temperature and high salinity are the major abiotic stresses that restrict cucumber growth and production, breeding materials with multiple abiotic resistance are in greatly need. Here we investigated the effect of introducing the LOS5 gene, a key regulator of ABA biosynthesis in Arabidopsis thaliana, under the stress-responsive RD29A promoter into cucumber (Cucumis sativus L. cv. S516). We found that T1 RD29A-LOS5 transgenic lines have enhanced tolerance to cold and salt stresses. Specifically, transgenic lines exhibited dwarf phenotypes with reduced leaf number, shorter internode, decreased length of the biggest leaf, fewer female flowers, shorter fruit neck and lower vitamin C (Vc). The increased cold tolerance can be reflected from the significantly decreased cold index, the reduced electrolyte leakage index and the MDA content upon cold treatment as compared to those in the control. This may result from the accumulation of internal ABA, soluble sugars and proline, and the enhanced activities of protective enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in the transgenic lines. Under salt treatment, the transgenic lines exhibited increased germination index, vigor index, more lateral roots and increased root fresh weight. Moreover, RD29A-LOS5 transgenic plants displayed quicker responses in salt stress than that in low-temperature stress.

  20. Dominant Repression by Arabidopsis Transcription Factor MYB44 Causes Oxidative Damage and Hypersensitivity to Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Helene Persak

    2014-02-01

    Full Text Available In any living species, stress adaptation is closely linked with major changes of the gene expression profile. As a substrate protein of the rapidly stress-induced mitogen-activated protein kinase MPK3, Arabidopsis transcription factor MYB44 likely acts at the front line of stress-induced re-programming. We recently characterized MYB44 as phosphorylation-dependent positive regulator of salt stress signaling. Molecular events downstream of MYB44 are largely unknown. Although MYB44 binds to the MBSII element in vitro, it has no discernible effect on MBSII-driven reporter gene expression in plant co-transfection assays. This may suggest limited abundance of a synergistic co-regulator. MYB44 carries a putative transcriptional repression (Ethylene responsive element binding factor-associated Amphiphilic Repression, EAR motif. We employed a dominant repressor strategy to gain insights into MYB44-conferred stress resistance. Overexpression of a MYB44-REP fusion markedly compromised salt and drought stress tolerance—the opposite was seen in MYB44 overexpression lines. MYB44-mediated resistance likely results from induction of tolerance-enhancing, rather than from repression of tolerance-diminishing factors. Salt stress-induced accumulation of destructive reactive oxygen species is efficiently prevented in transgenic MYB44, but accelerated in MYB44-REP lines. Furthermore, heterologous overexpression of MYB44-REP caused tissue collapse in Nicotiana. A mechanistic model of MAPK-MYB-mediated enhancement in the antioxidative capacity and stress tolerance is proposed. Genetic engineering of MYB44 variants with higher trans-activating capacity may be a means to further raise stress resistance in crops.

  1. Alfalfa Cellulose synthase gene expression under abiotic stress: a Hitchhiker's guide to RT-qPCR normalization.

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    Gea Guerriero

    Full Text Available Abiotic stress represents a serious threat affecting both plant fitness and productivity. One of the promptest responses that plants trigger following abiotic stress is the differential expression of key genes, which enable to face the adverse conditions. It is accepted and shown that the cell wall senses and broadcasts the stress signal to the interior of the cell, by triggering a cascade of reactions leading to resistance. Therefore the study of wall-related genes is particularly relevant to understand the metabolic remodeling triggered by plants in response to exogenous stresses. Despite the agricultural and economical relevance of alfalfa (Medicago sativa L., no study, to our knowledge, has addressed specifically the wall-related gene expression changes in response to exogenous stresses in this important crop, by monitoring the dynamics of wall biosynthetic gene expression. We here identify and analyze the expression profiles of nine cellulose synthases, together with other wall-related genes, in stems of alfalfa plants subjected to different abiotic stresses (cold, heat, salt stress at various time points (e.g. 0, 24, 72 and 96 h. We identify 2 main responses for specific groups of genes, i.e. a salt/heat-induced and a cold/heat-repressed group of genes. Prior to this analysis we identified appropriate reference genes for expression analyses in alfalfa, by evaluating the stability of 10 candidates across different tissues (namely leaves, stems, roots, under the different abiotic stresses and time points chosen. The results obtained confirm an active role played by the cell wall in response to exogenous stimuli and constitute a step forward in delineating the complex pathways regulating the response of plants to abiotic stresses.

  2. Isolation and Expression Analysis of a Novel Abiotic Stress-Induced Gene W89 from Wheat

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rui-yue; XU Zhao-shi; LI Lian-cheng; CHEN Ming; MA You-zhi

    2007-01-01

    Water stress and cold stress are important factors restricting plant growth. However, there is little knowledge on the function of stress-responsive genes in plants. Therefore, it is necessary to clone some important genes to study the mechanism of plant adaptation to abiotic stress for improvement of plant resistance. A putative water stress-induced gene, W89, was cloned from the cDNA library of drought-treated wheat seedlings by phage hybridization in situ, and its entire length was obtained using 5'-rapid amplification of cDNA ends (RACE) and reverse transcription-polymerase chain reaction (RT-PCR). The full-length cDNA of W89 consists of 2 392 bp and contains a 1 896 bp open reading frame (ORF) encoding a 631 amino acid protein. Southern blot analysis indicated that W89 was a single-copy gene. RT-PCR analysis revealed that the expression of W89 was upregulated by drought, cold, and abscisic acid (ABA). Amino acid sequence analysis discovered that W89 had a conserved region of DUF248 (pfam03141), which contained a methyltransferase domain with a sterile alpha motif (SAM)-binding motif. Phylogenetic analysis showed that W89 was 66% identical to Oryza sativa dehydration-responsive protein (BAD67956). It was supposed that W89 was a novel dehydration-responsive protein encoding gene. On the basis of the functions of methyltransferase and the SAM-binding motif, the SAM-binding motif of W89 was supposed to be connected with other proteins or transcription factors to transduce stress signals and finally regulate the expression of stress-responsive genes on the early stage of drought stress.

  3. The α-Crystallin Domain Containing Genes: Identification, Phylogeny and Expression Profiling in Abiotic Stress, Phytohormone Response and Development in Tomato (Solanum lycopersicum

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    Asosii ePaul

    2016-03-01

    Full Text Available The α-crystallin domain (ACD is an ancient domain conserved among all kingdoms. Plant ACD proteins have roles in abiotic stresses, transcriptional regulation, inhibiting virus movement and DNA demethylation. An exhaustive in-silico analysis using Hidden Markof Model-based conserved motif search of the tomato proteome yielded a total of 50 ACD proteins that belonged to 4 groups, sub-divided further into18 classes. One of these groups belongs to the small heat shock protein (sHSP class of proteins, molecular chaperones implicated in heat tolerance. Both tandem and segmental duplication events appear to have shaped the expansion of this gene family with purifying selection being the primary driving force for evolution. The expression profiling of the Acd genes in two different heat stress regimes suggested that their transcripts are differentially regulated with roles in acclimation and adaptive response during recovery. The co-expression of various genes in response to different abiotic stresses (heat, low temperature, dehydration, salinity and oxidative stress and phytohormones (abscisic acid and salicylic acid suggested possible cross-talk between various members to combat a myriad of stresses. Further, several genes were highly expressed in fruit, root and flower tissues as compared to leaf signifying their importance in plant development too. Evaluation of the expression of this gene family in field grown tissues highlighted the prominent role they have in providing thermo-tolerance during daily temperature variations. The function of three putative sHSPs was established as holdase chaperones as evidenced by protection to malate-dehydrogenase against heat induced protein-aggregation. This study provides insights into the characterization of the Acd genes in tomato and forms the basis for further functional validation in-planta.

  4. Divergent DNA Methylation Patterns Associated with Abiotic Stress in Hevea brasiliensis

    Institute of Scientific and Technical Information of China (English)

    Thomas K. Uthup; Mlnlmol Ravindran; K. Bini; Saha Thakurdas

    2011-01-01

    Cytosine methylation is a fundamental epigenetic mechanism for gene-expression regulation and development in plants.Here,we report for the first time the identification of DNA methylation patterns and their putative relationship with abiotic stress in the tree crop Hevea brasiliensis (source of 99% of natural rubber in the world).Regulatory sequences of four major genes involved in the mevalonate pathway (rubber biosynthesis pathway) and one general defense-related gene of three high-yielding popular rubber clones grown at two different agroclimatic conditions were analyzed for the presence of methylation.We found several significant variations in the methylation pattern at core DNA binding motifs within all the five genes.Several consistent clone-specific and location-specific methylation patterns were identified.The differences in methylation pattern observed at certain pivotal cis-regulatory sites indicate the direct impact of stress on the genome and support the hypothesis of site-specific stress-induced DNA methylation.It is assumed that some of the methylation patterns observed may be involved in the stress-responsive mechanism in plants by which they adapt to extreme conditions.The study also provide clues towards the existence of highly divergent phenotypic characters among Hevea clones despite their very similar genetic make-up.Altogether,the observations from this study prove beyond doubt that there exist epigenetic variations in Hevea and environmental factors play a significant role in the induction of site-specific epigenetic mutations in its genome.

  5. Genomic Regions Associated with Tolerance to Freezing Stress and Snow Mold in Winter Wheat

    Directory of Open Access Journals (Sweden)

    Erika B. Kruse

    2017-03-01

    Full Text Available Plants grown through the winter are subject to selective pressures that vary with each year’s unique conditions, necessitating tolerance of numerous abiotic and biotic stress factors. The objective of this study was to identify molecular markers in winter wheat (Triticum aestivum L. associated with tolerance of two of these stresses, freezing temperatures and snow mold—a fungal disease complex active under snow cover. A population of 155 F2:5 recombinant inbred lines from a cross between soft white wheat cultivars “Finch” and “Eltan” was evaluated for snow mold tolerance in the field, and for freezing tolerance under controlled conditions. A total of 663 molecular markers was used to construct a genetic linkage map and identify marker-trait associations. One quantitative trait locus (QTL associated with both freezing and snow mold tolerance was identified on chromosome 5A. A second, distinct, QTL associated with freezing tolerance also was found on 5A, and a third on 4B. A second QTL associated with snow mold tolerance was identified on chromosome 6B. The QTL on 5A associated with both traits was closely linked with the Fr-A2 (Frost-Resistance A2 locus; its significant association with both traits may have resulted from pleiotropic effects, or from greater low temperature tolerance enabling the plants to better defend against snow mold pathogens. The QTL on 4B associated with freezing tolerance, and the QTL on 6B associated with snow mold tolerance have not been reported previously, and may be useful in the identification of sources of tolerance for these traits.

  6. Leaf ontogeny strongly influences photosynthetic tolerance to drought and high temperature in Gossypium hirsutum

    Science.gov (United States)

    Temperature and drought are major abiotic limitations to crop productivity worldwide. While abiotic stress physiology research has focused primarily on fully expanded leaves, no studies have investigated photosynthetic tolerance to concurrent drought and high temperature during leaf ontogeny. To add...

  7. EXOPOLYSACCHARIDE PRODUCTION BY DROUGHT TOLERANT BACILLUS SPP. AND EFFECT ON SOIL AGGREGATION UNDER DROUGHT STRESS

    Directory of Open Access Journals (Sweden)

    Sandhya Vardharajula

    2014-08-01

    Full Text Available Exopolysaccharides (EPS of microbial origin with novel functionality, reproducible physico-chemical properties, are important class of polymeric materials. EPS are believed to protect bacterial cells from dessication, produce biofilms, thus enhancing the cells chances of bacterial colonizing special ecological niches. In rhizosphere, EPS are known to be useful to improve the moisture-holding capacity. Three Bacillus spp. strains identified by 16s rDNA sequence analysis as B. amyloliquefaciens strain HYD-B17; B. licheniformis strain HYTAPB18; B. subtilis strain RMPB44 were studied for the ability to tolerate matric stress and produce EPS under different water potentials. EPS production in all the three Bacillus spp strains increased with increasing water stress indicating correlation between drought stress tolerance and EPS production. Among the isolates, strain HYD-17 showed highest production of EPS. The exopolysaccharide composition of the three strains was further analyzed by HPLC. Drought stress influenced the ratio of sugars in EPS and glucose was found as major sugar in strains HYTAPB18 and RMPB44 whereas raffinose was major sugar found in strain HYD-B17. Inoculation of EPS producing Bacillus spp. strains in soil resulted in good soil aggregation under drought stress conditions at different incubation periods. This study shows that exposure to water stress conditions affects the composition and ratios of sugars in EPS produced by Bacillus spp. strains HYD-B17, HYTAPB18 and RMPB44 influencing abiotic stress tolerance of the microorganisms.

  8. Evaluation of suitable reference genes for quantitative RT-PCR during development and abiotic stress in Panonychus citri (McGregor) (Acari: Tetranychidae).

    Science.gov (United States)

    Niu, Jin-Zhi; Dou, Wei; Ding, Tian-Bo; Yang, Li-Hong; Shen, Guang-Mao; Wang, Jin-Jun

    2012-05-01

    Quantitative real time reverse transcriptase polymerase chain reaction (RT-qPCR) is preferred for gene expression analysis in living organisms. Currently, it is a valuable tool for biological and ecological studies as it provides a relatively straightforward way to assess the relevance of transcriptional regulation under developmental and stress tolerance conditions. However, studies have shown that some commonly used reference genes varied among different experimental treatments, thus, systematic evaluation of reference genes is critical for gene expression profiling, which is often neglected in gene expression studies of arthropods. The aim of this study is to identify the suitable reference genes for RT-qPCR experiments involving various developmental stages and/or under abiotic stresses in citrus red mite Panonychus citri, a key pest in citrus orchards worldwide. GeNorm, NormFinder, and Bestkeeper software analysis indicates that elongation factor-1 alpha (ELF1A), RNA polymerase II largest subunit, alpha tublin, and glyceraldhyde-3-phosphate dehydrogenase (GAPDH) are the most stable reference genes in various developmental stages, meanwhile, ELF1A and GAPDH were the most stable reference genes under various abiotic stresses. Furthermore, this study will serve as a resource to screen reference genes for gene expression studies in any other spider mite species.

  9. Comprehensive expression profiling of rice tetraspanin genes reveals diverse roles during development and abiotic stress

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    Balaji eM

    2015-12-01

    Full Text Available Tetraspanin family is comprised of evolutionarily conserved integral membrane proteins. The incredible ability of tetraspanins to form ‘micro domain complexes’ and their preferential targeting to membranes emphasizes their active association with signal recognition and communication with neighboring cells, thus acting as key modulators of signaling cascades. In animals, tetraspanins are associated with multitude of cellular processes. Unlike animals, the biological relevance of tetraspanins in plants has not been well investigated. In Arabidopsis tetraspanins are known to contribute in important plant development processes such as leaf morphogenesis, root and floral organ formation. In the present study we investigated the genomic organization, chromosomal distribution, phylogeny and domain structure of 15 rice tetraspanin proteins (OsTETs. OsTET proteins had similar domain structure and signature ‘GCCK/R’ motif as reported in Arabidopsis. Comprehensive expression profiling of OsTET genes suggested their possible involvement during rice development. While OsTET9 and 10 accumulated predominantly in flowers, OsTET5, 8 and 12 were preferentially expressed in root tissues. Noticeably, seven OsTETs exhibited more than 2-fold up regulation at early stages of flag leaf senescence in rice. Furthermore, several OsTETs were differentially regulated in rice seedlings exposed to abiotic stresses, exogenous treatment of hormones and nutrient deprivation. Transient subcellular localization studies of eight OsTET proteins in tobacco epidermal cells showed that these proteins localized in plasma membrane. The present study provides valuable insights into the possible roles of tetraspanins in regulating development and defining response to abiotic stresses in rice. Targeted proteomic studies would be useful in identification of their interacting partners under different conditions and ultimately their biological function in plants

  10. Systematic Identification of Rice ABC1 Gene Family and Its Response to Abiotic Stress

    Institute of Scientific and Technical Information of China (English)

    GAO Qing-song; ZHANG Dan; Xu Liang; XU Chen-wu

    2011-01-01

    Members of the activity of bc1 complex (ABC1) family are protein kinases that are widely found in prokaryotes and eukaryotes.Previous studies showed that several plant ABC1 genes participated in the abiotic stress response.Here,we present the systematic identification of rice and Arabidopsis ABC1 genes and the expression analysis of rice ABC1 genes.A total of 15 and 17 ABC1 genes from the rice and Arabidopsis genomes,respectively,were identified using a bioinformatics approach.Phylogenetic analyses of these proteins suggested that the divergence of this family had occurred and their main characteristics were established before the monocot-dicot split.Indeed,species-specific expansion contributed to the evolution of this family in rice and Arabidopsis after the monocot-dicot split.Intron/exon structure analysis indicated that most of the orthologous genes had similar exon sizes,but diverse intron sizes,and the rice genes contained larger introns,moreover,intron gain was an important event accompanying the recent evolution of the rice ABC1 family.Multiple sequence alignment revealed one conserved amino acid segment and four conserved amino acids in the ABC1 domain.Online subcellular localization predicted that nine rice ABC1 proteins were localized in chloroplasts.Real-time RT-PCR established that the rice ABC1 genes were primarily expressed in leaves and the expression could be modulated by a broad range of abiotic factors such as H2O2,abscisic acid,low temperature,drought,darkness and high salinity.These results reveal that the rice ABC1 gene family plays roles in the environmental stress response and specific biological processes of rice.

  11. Abiotic stress modifies the synthesis of alpha-tocopherol and beta-carotene in phytoplankton species.

    Science.gov (United States)

    Häubner, Norbert; Sylvander, Peter; Vuori, Kristiina; Snoeijs, Pauline

    2014-08-01

    We performed laboratory experiments to investi-gate whether the synthesis of the antioxidants α-tocopherol (vitamin E) and β-carotene in phytoplankton depends on changes in abiotic factors. Cultures of Nodularia spumigena, Phaeodactylum tricornutum, Skeletonema costatum, Dunaliella tertiolecta, Prorocentrum cordatum, and Rhodomonas salina were incubated at different tempe-ratures, photon flux densities and salinities for 48 h. We found that abiotic stress, within natural ecological ranges, affects the synthesis of the two antioxidants in different ways in different species. In most cases antioxidant production was stimulated by increased abiotic stress. In P. tricornutum KAC 37 and D. tertiolecta SCCAP K-0591, both good producers of this compound, α-tocopherol accumulation was negatively affected by environmentally induced higher photosystem II efficiency (Fv /Fm ). On the other hand, β-carotene accumulation was positively affected by higher Fv /Fm in N. spumigena KAC 7, P. tricornutum KAC 37, D. tertiolecta SCCAP K-0591 and R. salina SCCAP K-0294. These different patterns in the synthesis of the two compounds may be explained by their different locations and functions in the cell. While α-tocopherol is heavily involved in the protection of prevention of lipid peroxidation in membranes, β-carotene performs immediate photo-oxidative protection in the antennae complex of photosystem II. Overall, our results suggest a high variability in the antioxidant pool of natural aquatic ecosystems, which can be subject to short-term temperature, photon flux density and salinity fluctuations. The antioxidant levels in natural phytoplankton communities depend on species composition, the physiological condition of the species, and their respective strategies to deal with reactive oxygen species. Since α-tocopherol and β-carotene, as well as many other nonenzymatic antioxidants, are exclusively produced by photo-synthetic organisms, and are required by higher

  12. Metal resistance or tolerance? Acidophiles confront high metal loads via both abiotic and biotic mechanisms

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    Mark eDopson

    2014-04-01

    Full Text Available All metals are toxic at high concentrations and consequently their intracellular concentrations must be regulated. Acidophilic microorganisms have an optimum growth pH < 3 and proliferate in natural and anthropogenic low pH environments. Some acidophiles are involved in the catalysis of sulfide mineral dissolution, resulting in high concentrations of metals in solution. Acidophiles are often described as highly metal resistant via mechanisms such as multiple and/or more efficient active resistance systems than are present in neutrophiles. However, this is not the case for all acidophiles and we contend that their growth in high metal concentrations is partially due to an intrinsic tolerance as a consequence of the environment in which they live. In this perspective, we highlight metal tolerance via complexation of free metals by sulfate ions and passive tolerance to metal influx via an internal positive cytoplasmic transmembrane potential. These tolerance mechanisms have been largely ignored in past studies of acidophile growth in the presence of metals and should be taken into account.

  13. Overexpression of pigeonpea stress-induced cold and drought regulatory gene (CcCDR) confers drought, salt, and cold tolerance in Arabidopsis.

    Science.gov (United States)

    Tamirisa, Srinath; Vudem, Dashavantha Reddy; Khareedu, Venkateswara Rao

    2014-09-01

    A potent cold and drought regulatory protein-encoding gene (CcCDR) was isolated from the subtractive cDNA library of pigeonpea plants subjected to drought stress. CcCDR was induced by different abiotic stress conditions in pigeonpea. Overexpression of CcCDR in Arabidopsis thaliana imparted enhanced tolerance against major abiotic stresses, namely drought, salinity, and low temperature, as evidenced by increased biomass, root length, and chlorophyll content. Transgenic plants also showed increased levels of antioxidant enzymes, proline, and reducing sugars under stress conditions. Furthermore, CcCDR-transgenic plants showed enhanced relative water content, osmotic potential, and cell membrane stability, as well as hypersensitivity to abscisic acid (ABA) as compared with control plants. Localization studies confirmed that CcCDR could enter the nucleus, as revealed by intense fluorescence, indicating its possible interaction with various nuclear proteins. Microarray analysis revealed that 1780 genes were up-regulated in CcCDR-transgenics compared with wild-type plants. Real-time PCR analysis on selected stress-responsive genes, involved in ABA-dependent and -independent signalling networks, revealed higher expression levels in transgenic plants, suggesting that CcCDR acts upstream of these genes. The overall results demonstrate the explicit role of CcCDR in conferring multiple abiotic stress tolerance at the whole-plant level. The multifunctional CcCDR seems promising as a prime candidate gene for enhancing abiotic stress tolerance in diverse plants.

  14. Depletion of Key Meiotic Genes and Transcriptome-Wide Abiotic Stress Reprogramming Mark Early Preparatory Events Ahead of Apomeiotic Transition

    Science.gov (United States)

    Shah, Jubin N.; Kirioukhova, Olga; Pawar, Pallavi; Tayyab, Muhammad; Mateo, Juan L.; Johnston, Amal J.

    2016-01-01

    Molecular dissection of apomixis – an asexual reproductive mode – is anticipated to solve the enigma of loss of meiotic sex, and to help fixing elite agronomic traits. The Brassicaceae genus Boechera comprises of both sexual and apomictic species, permitting comparative analyses of meiotic circumvention (apomeiosis) and parthenogenesis. Whereas previous studies reported local transcriptome changes during these events, it remained unclear whether global changes associated with hybridization, polyploidy and environmental adaptation that arose during evolution of Boechera might serve as (epi)genetic regulators of early development prior apomictic initiation. To identify these signatures during vegetative stages, we compared seedling RNA-seq transcriptomes of an obligate triploid apomict and a diploid sexual, both isolated from a drought-prone habitat. Uncovered were several genes differentially expressed between sexual and apomictic seedlings, including homologs of meiotic genes ASYNAPTIC 1 (ASY1) and MULTIPOLAR SPINDLE 1 (MPS1) that were down-regulated in apomicts. An intriguing class of apomict-specific deregulated genes included several NAC transcription factors, homologs of which are known to be transcriptionally reprogrammed during abiotic stress in other plants. Deregulation of both meiotic and stress-response genes during seedling stages might possibly be important in preparation for meiotic circumvention, as similar transcriptional alteration was discernible in apomeiotic floral buds too. Furthermore, we noted that the apomict showed better tolerance to osmotic stress in vitro than the sexual, in conjunction with significant upregulation of a subset of NAC genes. In support of the current model that DNA methylation epigenetically regulates stress, ploidy, hybridization and apomixis, we noted that ASY1, MPS1 and NAC019 homologs were deregulated in Boechera seedlings upon DNA demethylation, and ASY1 in particular seems to be repressed by global DNA

  15. Genes for iron-sulphur cluster assembly are targets of abiotic stress in rice, Oryza sativa.

    Science.gov (United States)

    Liang, Xuejiao; Qin, Lu; Liu, Peiwei; Wang, Meihuan; Ye, Hong

    2014-03-01

    Iron-sulphur (Fe-S) cluster assembly occurs in chloroplasts, mitochondria and cytosol, involving dozens of genes in higher plants. In this study, we have identified 41 putative Fe-S cluster assembly genes in rice (Oryza sativa) genome, and the expression of all genes was verified. To investigate the role of Fe-S cluster assembly as a metabolic pathway, we applied abiotic stresses to rice seedlings and analysed Fe-S cluster assembly gene expression by qRT-PCR. Our data showed that genes for Fe-S cluster assembly in chloroplasts of leaves are particularly sensitive to heavy metal treatments, and that Fe-S cluster assembly genes in roots were up-regulated in response to iron toxicity, oxidative stress and some heavy metal assault. The effect of each stress treatment on the Fe-S cluster assembly machinery demonstrated an unexpected tissue or organelle specificity, suggesting that the physiological relevance of the Fe-S cluster assembly is more complex than thought. Furthermore, our results may reveal potential candidate genes for molecular breeding of rice.

  16. Non-destructive Phenotyping to Identify Brachiaria Hybrids Tolerant to Waterlogging Stress under Field Conditions.

    Science.gov (United States)

    Jiménez, Juan de la Cruz; Cardoso, Juan A; Leiva, Luisa F; Gil, Juanita; Forero, Manuel G; Worthington, Margaret L; Miles, John W; Rao, Idupulapati M

    2017-01-01

    Brachiaria grasses are sown in tropical regions around the world, especially in the Neotropics, to improve livestock production. Waterlogging is a major constraint to the productivity and persistence of Brachiaria grasses during the rainy season. While some Brachiaria cultivars are moderately tolerant to seasonal waterlogging, none of the commercial cultivars combines superior yield potential and nutritional quality with a high level of waterlogging tolerance. The Brachiaria breeding program at the International Center for Tropical Agriculture, has been using recurrent selection for the past two decades to combine forage yield with resistance to biotic and abiotic stress factors. The main objective of this study was to test the suitability of normalized difference vegetation index (NDVI) and image-based phenotyping as non-destructive approaches to identify Brachiaria hybrids tolerant to waterlogging stress under field conditions. Nineteen promising hybrid selections from the breeding program and three commercial checks were evaluated for their tolerance to waterlogging under field conditions. The waterlogging treatment was imposed by applying and maintaining water to 3 cm above soil surface. Plant performance was determined non-destructively using proximal sensing and image-based phenotyping and also destructively via harvesting for comparison. Image analysis of projected green and dead areas, NDVI and shoot biomass were positively correlated (r ≥ 0.8). Our results indicate that image analysis and NDVI can serve as non-destructive screening approaches for the identification of Brachiaria hybrids tolerant to waterlogging stress.

  17. Non-destructive Phenotyping to Identify Brachiaria Hybrids Tolerant to Waterlogging Stress under Field Conditions

    Science.gov (United States)

    Jiménez, Juan de la Cruz; Cardoso, Juan A.; Leiva, Luisa F.; Gil, Juanita; Forero, Manuel G.; Worthington, Margaret L.; Miles, John W.; Rao, Idupulapati M.

    2017-01-01

    Brachiaria grasses are sown in tropical regions around the world, especially in the Neotropics, to improve livestock production. Waterlogging is a major constraint to the productivity and persistence of Brachiaria grasses during the rainy season. While some Brachiaria cultivars are moderately tolerant to seasonal waterlogging, none of the commercial cultivars combines superior yield potential and nutritional quality with a high level of waterlogging tolerance. The Brachiaria breeding program at the International Center for Tropical Agriculture, has been using recurrent selection for the past two decades to combine forage yield with resistance to biotic and abiotic stress factors. The main objective of this study was to test the suitability of normalized difference vegetation index (NDVI) and image-based phenotyping as non-destructive approaches to identify Brachiaria hybrids tolerant to waterlogging stress under field conditions. Nineteen promising hybrid selections from the breeding program and three commercial checks were evaluated for their tolerance to waterlogging under field conditions. The waterlogging treatment was imposed by applying and maintaining water to 3 cm above soil surface. Plant performance was determined non-destructively using proximal sensing and image-based phenotyping and also destructively via harvesting for comparison. Image analysis of projected green and dead areas, NDVI and shoot biomass were positively correlated (r ≥ 0.8). Our results indicate that image analysis and NDVI can serve as non-destructive screening approaches for the identification of Brachiaria hybrids tolerant to waterlogging stress. PMID:28243249

  18. Characterization of reference genes for RT-qPCR in the desert moss Syntrichia caninervis in response to abiotic stress and desiccation/rehydration

    Directory of Open Access Journals (Sweden)

    Xiaoshuang eLi

    2015-02-01

    Full Text Available Syntrichia caninervis is the dominant bryophyte of the biological soil crusts found in the Gurbantunggut desert. The extreme desert environment is characterized by prolonged drought, temperature extremes, high radiation and frequent cycles of hydration and dehydration. S. caninervis is an ideal organism for the identification and characterization of genes related to abiotic stress tolerance. RT-qPCR expression analysis is a powerful analytical technique that requires the use of stable reference genes. Using available S. caninervis transcriptome data, we selected 15 candidate reference genes and analyzed their relative expression stabilities in S. caninervis gametophores exposed to a range of abiotic stresses or a hydration-desiccation-rehydration cycle. The programs geNorm, NormFinder, and RefFinder were used to assess and rank the expression stability of the 15 candidate genes. The stability ranking results of reference genes under each specific experimental condition showed high consistency using different algorithms. For abiotic stress treatments, the combination of two genes (α-TUB2 and CDPK were sufficient for accurate normalization. For the hydration-desiccation-rehydration process, the combination of two genes (α-TUB1 and CDPK were sufficient for accurate normalization. 18S was among the least stable genes in all of the experimental sets and was unsuitable as reference gene in S. caninervis. This is the first systematic investigation and comparison of reference gene selection for RT-qPCR work in S. caninervis. This research will facilitate gene expression studies in S. caninervis, related moss species from the Syntrichia complex and other mosses.

  19. Resilience of Penicillium resedanum LK6 and exogenous gibberellin in improving Capsicum annuum growth under abiotic stresses.

    Science.gov (United States)

    Khan, Abdul Latif; Waqas, Muhammad; Lee, In-Jung

    2015-03-01

    Understanding how endophytic fungi mitigate abiotic stresses in plants will be important in a changing global climate. A few endophytes can produce phytohormones, but their ability to induce physiological changes in host plants during extreme environmental conditions are largely unexplored. In the present study, we investigated the ability of Penicillium resedanum LK6 to produce gibberellins and its role in improving the growth of Capsicum annuum L. under salinity, drought, and heat stresses. These effects were compared with exogenous application of gibberellic acid (GA3). Endophyte treatment significantly increased shoot length, biomass, chlorophyll content, and the photosynthesis rate compared with the uninfected control during abiotic stresses. The endophyte and combined endophyte + GA3 treatments significantly ameliorated the negative effects of stresses compared with the control. Stress-responsive endogenous abscisic acid and its encoding genes, such as zeaxanthin epoxidase, 9-cis-epoxycarotenoid dioxygenase 3, and ABA aldehyde oxidase 3, were significantly reduced in endophyte-treated plants under stress. Conversely, salicylic acid and biosynthesis-related gene (isochorismate synthase) had constitutive expressions while pathogenesis related (PR1 and PR5) genes showed attenuated responses during endophyte treatment under abiotic stresses. The present findings suggest that endophytes have effects comparable to those of exogenous GA3; both can significantly increase plant growth and yield under changing environmental conditions by reprogramming the host plant's physiological responses.

  20. Osmotic stress represses strigolactone biosynthesis in Lotus japonicus roots: exploring the interaction between strigolactones and ABA under abiotic stress

    KAUST Repository

    Liu, Junwei

    2015-02-26

    Main conclusion: Strigolactone changes and cross talk with ABA unveil a picture of root-specific hormonal dynamics under stress.Abstract: Strigolactones (SLs) are carotenoid-derived hormones influencing diverse aspects of development and communication with (micro)organisms, and proposed as mediators of environmental stimuli in resource allocation processes; to contribute to adaptive adjustments, therefore, their pathway must be responsive to environmental cues. To investigate the relationship between SLs and abiotic stress in Lotus japonicus, we compared wild-type and SL-depleted plants, and studied SL metabolism in roots stressed osmotically and/or phosphate starved. SL-depleted plants showed increased stomatal conductance, both under normal and stress conditions, and impaired resistance to drought associated with slower stomatal closure in response to abscisic acid (ABA). This confirms that SLs contribute to drought resistance in species other than Arabidopsis. However, we also observed that osmotic stress rapidly and strongly decreased SL concentration in tissues and exudates of wild-type Lotus roots, by acting on the transcription of biosynthetic and transporter-encoding genes and independently of phosphate abundance. Pre-treatment with exogenous SLs inhibited the osmotic stress-induced ABA increase in wild-type roots and down-regulated the transcription of the ABA biosynthetic gene LjNCED2. We propose that a transcriptionally regulated, early SL decrease under osmotic stress is needed (but not sufficient) to allow the physiological increase of ABA in roots. This work shows that SL metabolism and effects on ABA are seemingly opposite in roots and shoots under stress.

  1. Oil palm EgCBF3 conferred stress tolerance in transgenic tomato plants through modulation of the ethylene signaling pathway.

    Science.gov (United States)

    Ebrahimi, Mortaza; Abdullah, Siti Nor Akmar; Abdul Aziz, Maheran; Namasivayam, Parameswari

    2016-09-01

    CBF/DREB1 is a group of transcription factors that are mainly involved in abiotic stress tolerance in plants. They belong to the AP2/ERF superfamily of plant-specific transcription factors. A gene encoding a new member of this group was isolated from ripening oil palm fruit and designated as EgCBF3. The oil palm fruit demonstrates the characteristics of a climacteric fruit like tomato, in which ethylene has a major impact on the ripening process. A transgenic approach was used for functional characterization of the EgCBF3, using tomato as the model plant. The effects of ectopic expression of EgCBF3 were analyzed based on expression profiling of the ethylene biosynthesis-related genes, anti-freeze proteins (AFPs), abiotic stress tolerance and plant growth and development. The EgCBF3 tomatoes demonstrated altered phenotypes compared to the wild type tomatoes. Delayed leaf senescence and flowering, increased chlorophyll content and abnormal flowering were the consequences of overexpression of EgCBF3 in the transgenic tomatoes. The EgCBF3 tomatoes demonstrated enhanced abiotic stress tolerance under in vitro conditions. Further, transcript levels of ethylene biosynthesis-related genes, including three SlACSs and two SlACOs, were altered in the transgenic plants' leaves and roots compared to that in the wild type tomato plant. Among the eight AFPs studied in the wounded leaves of the EgCBF3 tomato plants, transcript levels of SlOSM-L, SlNP24, SlPR5L and SlTSRF1 decreased, while expression of the other four, SlCHI3, SlPR1, SlPR-P2 and SlLAP2, were up-regulated. These findings indicate the possible functions of EgCBF3 in plant growth and development as a regulator of ethylene biosynthesis-related and AFP genes, and as a stimulator of abiotic stress tolerance.

  2. Interaction of brassinosteroids and polyamines enhances copper stress tolerance in raphanus sativus.

    Science.gov (United States)

    Choudhary, Sikander Pal; Oral, H Volkan; Bhardwaj, Renu; Yu, Jing-Quan; Tran, Lam-Son Phan

    2012-09-01

    Brassinosteroids (BRs) and polyamines (PAs) regulate various responses to abiotic stress, but their involvement in the regulation of copper (Cu) homeostasis in plants exposed to toxic levels of Cu is poorly understood. This study provides an analysis of the effects of exogenously applied BRs and PAs on radish (Raphanus sativus) plants exposed to toxic concentrations of Cu. The interaction of 24-epibrassinolide (EBR, an active BR) and spermidine (Spd, an active PA) on gene expression and the physiology of radish plants resulted in enhanced tolerance to Cu stress. Results indicated that the combined application of EBR and Spd modulated the expression of genes encoding PA enzymes and genes that impact the metabolism of indole-3-acetic acid (IAA) and abscisic acid (ABA) resulting in enhanced Cu stress tolerance. Altered expression of genes implicated in Cu homeostasis appeared to be the main effect of EBR and Spd leading to Cu stress alleviation in radish. Ion leakage, in vivo imaging of H(2)O(2), comet assay, and improved tolerance of Cu-sensitive yeast strains provided further evidence for the ability of EBR and Spd to improve Cu tolerance significantly. The study indicates that co-application of EBR and Spd is an effective approach for Cu detoxification and the maintenance of Cu homeostasis in plants. Therefore, the use of these compounds in agricultural production systems should be explored.

  3. A Nucleocytoplasmic Shuttling Protein in Oxidative Stress Tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Ow, David W.; Song, Wen

    2003-03-26

    Plants for effective extraction of toxic metals and radionuclides must tolerate oxidative stress. To identify genes that enhance oxidative stress tolerance, an S. pombe cDNA expression plasmid library was screened for the ability to yield hypertolerant colonies. Here, we report on the properties of one gene that confers hypertolerance to cadmium and oxidizing chemicals. This gene appears to be conserved in other organisms as homologous genes are found in human, mouse, fruitfly and Arabidopsis. The fruitfly and Arabidopsis genes likewise enhance oxidative stress tolerance in fission yeast. During oxidative stress, the amount of mRNA does not change, but protein fusions to GFP relocate from the cytoplasm to the nucleus. The same pattern is observed with the Arabidopsis homologue-GFP fusion protein. This behavior suggests a signaling role in oxidative stress tolerance and these conserved proteins may be targets for engineering stress tolerant plants for phytoremediation.

  4. Comprehensive analysis of trihelix genes and their expression under biotic and abiotic stresses in Populus trichocarpa

    Science.gov (United States)

    Wang, Zhanchao; Liu, Quangang; Wang, Hanzeng; Zhang, Haizhen; Xu, Xuemei; Li, Chenghao; Yang, Chuanping

    2016-01-01

    Trihelix genes play important roles in plant growth and development and responses to biotic and abiotic stresses. Here, we identified 56 full-length trihelix genes in Populus trichocarpa and classified them into five groups. Most genes within a given group had similar gene structures and conserved motifs. The trihelix genes were unequally distributed across 19 different linkage groups. Fifteen paralogous pairs were identified, 14 of which have undergone segmental duplication events. Promoter cis-element analysis indicated that most trihelix genes contain stress- or phytohormone-related cis-elements. The expression profiles of the trihelix genes suggest that they are primarily expressed in leaves and roots. Quantitative real-time reverse transcription polymerase chain reaction analysis indicated that members of the trihelix gene family are significantly induced in response to osmotic, abscisic acid, salicylic acid, methyl jasmonate and pathogen infection. PtrGT10 was identified as a target gene of miR172d, which is involved in the osmotic response. Repression of PtrGT10 could increase reactive oxygen species scavenging ability and decrease cell death. This study provides novel insights into the phylogenetic relationships and functions of the P. trichocarpa trihelix genes, which will aid future functional studies investigating the divergent roles of trihelix genes belonging to other species. PMID:27782188

  5. Transcriptomic analysis of grain amaranth (Amaranthus hypochondriacus using 454 pyrosequencing: comparison with A. tuberculatus, expression profiling in stems and in response to biotic and abiotic stress

    Directory of Open Access Journals (Sweden)

    Vargas-Ortiz Erandi

    2011-07-01

    Full Text Available Abstract Background Amaranthus hypochondriacus, a grain amaranth, is a C4 plant noted by its ability to tolerate stressful conditions and produce highly nutritious seeds. These possess an optimal amino acid balance and constitute a rich source of health-promoting peptides. Although several recent studies, mostly involving subtractive hybridization strategies, have contributed to increase the relatively low number of grain amaranth expressed sequence tags (ESTs, transcriptomic information of this species remains limited, particularly regarding tissue-specific and biotic stress-related genes. Thus, a large scale transcriptome analysis was performed to generate stem- and (abiotic stress-responsive gene expression profiles in grain amaranth. Results A total of 2,700,168 raw reads were obtained from six 454 pyrosequencing runs, which were assembled into 21,207 high quality sequences (20,408 isotigs + 799 contigs. The average sequence length was 1,064 bp and 930 bp for isotigs and contigs, respectively. Only 5,113 singletons were recovered after quality control. Contigs/isotigs were further incorporated into 15,667 isogroups. All unique sequences were queried against the nr, TAIR, UniRef100, UniRef50 and Amaranthaceae EST databases for annotation. Functional GO annotation was performed with all contigs/isotigs that produced significant hits with the TAIR database. Only 8,260 sequences were found to be homologous when the transcriptomes of A. tuberculatus and A. hypochondriacus were compared, most of which were associated with basic house-keeping processes. Digital expression analysis identified 1,971 differentially expressed genes in response to at least one of four stress treatments tested. These included several multiple-stress-inducible genes that could represent potential candidates for use in the engineering of stress-resistant plants. The transcriptomic data generated from pigmented stems shared similarity with findings reported in developing

  6. Polyamine Accumulation in Transgenic Tomato Enhances the Tolerance to High Temperature Stress

    Institute of Scientific and Technical Information of China (English)

    Lin Cheng; Yijing Zou; Shuli Ding; Jiajing Zhang; Xiaolin Yu; Jiashu Cao; Gang Lu

    2009-01-01

    Polyamines play an important role in plant response to abiotic stress. S-adenosyl-I-methionine decarboxylase (SAMDC) is one of the key regulatory enzymes in the biosynthesis of polyamines. In order to better understand the effect of regulation of polyamine biosynthesis on the tolerance of high-temperature stress in tomato, SAMDC Cdna isolated from Saccharomyces cerevisiae was introduced into tomato genome by means of Agrobacterium tumefaciens through leaf disc transformation. Transgene and expression was confirmed by Southern and Northern blot analyses, respectively. Transgenic plants expressing yeast SAMDC produced 1.7- to 2.4-fold higher levels of spermidine and spermine than wild-type plants under high temperature stress, and enhanced antioxidant enzyme activity and the protection of membrane lipid peroxidation was also observed. This subsequently improved the efficiency of CO2 assimilation and protected the plants from high temperature stress, which indicated that the transgenic tomato presented an enhanced tolerance to high temperature stress (38℃) compared with wild-type plants, Our results demonstrated clearly that increasing polyamine biosynthesis in plants may be a means of creating high temperature-tolerant germplasm.

  7. Osmotic stress tolerance in semi-terrestrial tardigrades

    DEFF Research Database (Denmark)

    Heidemann, Nanna W T; Smith, Daniel K.; Hygum, Thomas L.;

    2016-01-01

    Little is known about ionic and osmotic stress tolerance in tardigrades. Here, we examine salt stress tolerance in Ramazzottius oberhaeuseri and Echiniscus testudo from Nivå (Denmark) and address whether limno-terrestrial tardigrades can enter a state of quiescence (osmobiosis) in the face of hig...

  8. Osmotic stress tolerance in semi-terrestrial tardigrades

    DEFF Research Database (Denmark)

    Heidemann, Nanna W T; Smith, Daniel K.; Hygum, Thomas L.;

    2016-01-01

    Little is known about ionic and osmotic stress tolerance in tardigrades. Here, we examine salt stress tolerance in Ramazzottius oberhaeuseri and Echiniscus testudo from Nivå (Denmark) and address whether limno-terrestrial tardigrades can enter a state of quiescence (osmobiosis) in the face of high...

  9. The Opuntia streptacantha OpsHSP18 Gene Confers Salt and Osmotic Stress Tolerance in Arabidopsis thaliana

    Science.gov (United States)

    Salas-Muñoz, Silvia; Gómez-Anduro, Gracia; Delgado-Sánchez, Pablo; Rodríguez-Kessler, Margarita; Jiménez-Bremont, Juan Francisco

    2012-01-01

    Abiotic stress limits seed germination, plant growth, flowering and fruit quality, causing economic decrease. Small Heat Shock Proteins (sHSPs) are chaperons with roles in stress tolerance. Herein, we report the functional characterization of a cytosolic class CI sHSP (OpsHSP18) from Opuntia streptacantha during seed germination in Arabidopsis thaliana transgenic lines subjected to different stress and hormone treatments. The over-expression of the OpsHSP18 gene in A. thaliana increased the seed germination rate under salt (NaCl) and osmotic (glucose and mannitol) stress, and in ABA treatments, compared with WT. On the other hand, the over-expression of the OpsHSP18 gene enhanced tolerance to salt (150 mM NaCl) and osmotic (274 mM mannitol) stress in Arabidopsis seedlings treated during 14 and 21 days, respectively. These plants showed increased survival rates (52.00 and 73.33%, respectively) with respect to the WT (18.75 and 53.75%, respectively). Thus, our results show that OpsHSP18 gene might have an important role in abiotic stress tolerance, in particular in seed germination and survival rate of Arabidopsis plants under unfavorable conditions. PMID:22949853

  10. Putrescine accumulation in Arabidopsis thaliana transgenic lines enhances tolerance to dehydration and freezing stress.

    Science.gov (United States)

    Alet, Analía I; Sanchez, Diego H; Cuevas, Juan C; Del Valle, Secundino; Altabella, Teresa; Tiburcio, Antonio F; Marco, Francisco; Ferrando, Alejandro; Espasandín, Fabiana D; González, María E; Ruiz, Oscar A; Carrasco, Pedro

    2011-02-01

    Polyamines have been globally associated to plant responses to abiotic stress. Particularly, putrescine has been related to a better response to cold and dehydration stresses. It is known that this polyamine is involved in cold tolerance, since Arabidopsis thaliana plants mutated in the key enzyme responsible for putrescine synthesis (arginine decarboxilase, ADC; EC 4.1.1.19) are more sensitive than the wild type to this stress. Although it is speculated that the over-expression of ADC genes may confer tolerance, this is hampered by pleiotropic effects arising from the constitutive expression of enzymes from the polyamine metabolism. Here, we present our work using A. thaliana transgenic plants harboring the ADC gene from oat under the control of a stress-inducible promoter (pRD29A) instead of a constitutive promoter. The transgenic lines presented in this work were more resistant to both cold and dehydration stresses, associated with a concomitant increment in endogenous putrescine levels under stress. Furthermore, the increment in putrescine upon cold treatment correlated with the induction of known stress-responsive genes, and suggested that putrescine may be directly or indirectly involved in ABA metabolism and gene expression.

  11. A bi-functional xyloglucan galactosyltransferase is an indispensable salt stress tolerance determinant in arabidop

    KAUST Repository

    Li, Wenbo

    2013-07-01

    Salinity is an abiotic stress that substantially limits crop production worldwide. To identify salt stress tolerance determinants, we screened for Arabidopsis mutants that are hypersensitive to salt stress and designated these mutants as short root in salt medium (rsa). One of these mutants, rsa3-1, is hypersensitive to NaCl and LiCl but not to CsCl or to general osmotic stress. Reactive oxygen species (ROS) over-accumulate in rsa3-1 plants under salt stress. Gene expression profiling with Affymetrix microarray analysis revealed that RSA3 controls expression of many genes including genes encoding proteins for ROS detoxification under salt stress. Map-based cloning showed that RSA3 encodes a xyloglucan galactosyltransferase, which is allelic to a gene previously named MUR3/KAM1. The RSA3/ MUR3/KAM1-encoded xylogluscan galactosyltransferase regulates actin microfilament organization (and thereby contributes to endomembrane distribution) and is also involved in cell wall biosynthesis. In rsa3-1, actin cannot assemble and form bundles as it does in the wild-type but instead aggregates in the cytoplasm. Furthermore, addition of phalloidin, which prevents actin depolymerization, can rescue salt hypersensitivity of rsa3-1. Together, these results suggest that RSA3/MUR3/KAM1 along with other cell wall-associated proteins plays a critical role in salt stress tolerance by maintaining the proper organization of actin microfilaments in order to minimize damage caused by excessive ROS. © 2013 The Author.

  12. Functional analysis of the durum wheat gene TdPIP2;1 and its promoter region in response to abiotic stress in rice.

    Science.gov (United States)

    Ayadi, Malika; Mieulet, Delphine; Fabre, Denis; Verdeil, Jean-Luc; Vernet, Aurore; Guiderdoni, Emmanuel; Masmoudi, Khaled

    2014-06-01

    In a previous work, we demonstrated that expression of TdPIP2;1 in Xenopus oocytes resulted in an increase in Pf compared to water injected oocytes. Phenotypic analyses of transgenic tobacco plants expressing TdPIP2;1 generated a tolerance phenotype towards drought and salinity stresses. To elucidate its stress tolerance mechanism at the transcriptional level, we isolated and characterized the promoter region of the TdPIP2;1 gene. A 1060-bp genomic fragment upstream of the TdPIP2;1 translated sequence has been isolated, cloned, and designated as the proTdPIP2;1 promoter. Sequence analysis of proTdPIP2;1 revealed the presence of cis regulatory elements which could be required for abiotic stress responsiveness, for tissue-specific and vascular expression. The proTdPIP2;1 promoter was fused to the β-glucuronidase (gusA) gene and the resulting construct was transferred into rice (cv. Nipponbare). Histochemical analysis of proTdPIP2;1::Gus in rice plants revealed that the GUS activity was observed in leaves, stems and roots of stably transformed rice T3 plants. Histological sections prepared revealed accumulation of GUS products in phloem, xylem and in some cells adjacent to xylem. The transcripts were up-regulated by dehydration. Transgenic rice plants overexpressing proTdPIP2;1 in fusion with TdPIP2;1, showed enhanced drought tolerance, while wild type plants were more sensitive and exhibited symptoms of wilting and chlorosis. These findings suggest that expression of the TdPIP2;1 gene regulated by its own promoter achieves enhanced drought tolerance in rice.

  13. Expression Analysis of MYC Genes from Tamarix hispida in Response to Different Abiotic Stresses

    Directory of Open Access Journals (Sweden)

    Guifeng Liu

    2012-01-01

    Full Text Available The MYC genes are a group of transcription factors containing both bHLH and ZIP motifs that play important roles in the regulation of abscisic acid (ABA-responsive genes. In the present study, to investigate the roles of MYC genes under NaCl, osmotic and ABA stress conditions, nine MYC genes were cloned from Tamarix hispida. Real-time reverse-transcriptase (RT-PCR showed that all nine MYC genes were expressed in root, stem and leaf tissues, but that the levels of the transcripts of these genes in the various tissues differed notably. The MYC genes were highly induced in the roots in response to ABA, NaCl and osmotic stresses after 3 h; however, in the stem and leaf tissues, MYC genes were highly induced only when exposed to these stresses for 6 h. In addition, most of these MYC genes were highly expressed in roots in comparison with stems and leaves. Furthermore, the MYC genes were more highly induced in roots than in stem and leaf tissues, indicating that these genes may play roles in stress responses mainly in the roots rather than the stems and leaves. The results of this present study suggest that MYCs are involved in salt and osmotic stress tolerances and are controlled by the ABA signal transduction pathway.

  14. Expression of Cryptogein in tobacco plants exhibits enhanced disease resistance and tolerance to salt stress

    Institute of Scientific and Technical Information of China (English)

    JIANG Donghua; CHEN Xujun; WU Kunlu; GUO Zejian

    2004-01-01

    Cryptogein (Crypt), an elicitin secreted from Phytophthora cryptogea, was used for genetic engineering of biotic and abiotic resistance plants. We generated transgenic tobacco plants harboring a rice phenylalanine ammonia-lyase (PAL) promoter and Crypt fusion gene (PAL::Crypt) or the mutated Crypt (mutation of the lysine at the position 13 to valine) under the control CaMV35S promoter (CaMV35S::CryK13V). T2 progeny of the transgenic plants showed significantly enhanced disease resistance to pathogens of fungal Phytophthora parasitica var nicotiana (Ppn) and Alternaria alternata, and bacterial Pseudomonas syringae pv tabaci. The amount of mRNA accumulation of Crypt and CryK13V was quite low in the transgenic lines analyzed by Northern blot, and was detected by a reverse transcription PCR method. Plants harboring PAL::Crypt construct showed faster and stronger induction of PR-1a gene after Ppn inoculation than that in the wild-type plants. The results suggested that the inducible PAL promoter could rapidly respond to pathogen attack and efficiently suppress the pathogen infection. Furthermore, the enhanced tolerance to salt stress in both of the Crypt and CryK13V expressing tobacco plants was also observed compared with that in the control plants. The constitutive expression of PR and transcription factor genes in the transformants was probably associated with the salt tolerance. The above observations suggested that a cross-talk between biotic and abiotic stresses existed in tobacco plants.

  15. Transcript Profiling Reveals the Presence of Abiotic Stress and Developmental Stage Specific Ascorbate Oxidase Genes in Plants

    Science.gov (United States)

    Batth, Rituraj; Singh, Kapil; Kumari, Sumita; Mustafiz, Ananda

    2017-01-01

    Abiotic stress and climate change is the major concern for plant growth and crop yield. Abiotic stresses lead to enhanced accumulation of reactive oxygen species (ROS) consequently resulting in cellular damage and major losses in crop yield. One of the major scavengers of ROS is ascorbate (AA) which acts as first line of defense against external oxidants. An enzyme named ascorbate oxidase (AAO) is known to oxidize AA and deleteriously affect the plant system in response to stress. Genome-wide analysis of AAO gene family has led to the identification of five, three, seven, four, and six AAO genes in Oryza sativa, Arabidopsis, Glycine max, Zea mays, and Sorghum bicolor genomes, respectively. Expression profiling of these genes was carried out in response to various abiotic stresses and during various stages of vegetative and reproductive development using publicly available microarray database. Expression analysis in Oryza sativa revealed tissue specific expression of AAO genes wherein few members were exclusively expressed in either root or shoot. These genes were found to be regulated by both developmental cues as well as diverse stress conditions. The qRT-PCR analysis in response to salinity and drought stress in rice shoots revealed OsAAO2 to be the most stress responsive gene. On the other hand, OsAAO3 and OsAAO4 genes showed enhanced expression in roots under salinity/drought stresses. This study provides lead about important stress responsive AAO genes in various crop plants, which could be used to engineer climate resilient crop plants. PMID:28261251

  16. Calcium sensors as key hubs in plant responses to biotic and abiotic stresses

    Directory of Open Access Journals (Sweden)

    Benoît eRanty

    2016-03-01

    Full Text Available The Ca2+ ion is recognized as a crucial second messenger in signalling pathways coupling the perception of environmental stimuli to plant adaptive responses. Indeed, one of the earliest events following the perception of environmental changes (temperature, salt stress, drought, pathogen or herbivore attack is intracellular variation of free calcium concentrations. These calcium variations differ in their spatio-temporal characteristics (subcellular location, amplitude, kinetics with the nature and strength of the stimulus and, for this reason, they are considered as signatures encrypting information from the initial stimulus. This information is believed to drive a specific response by decoding via calcium-binding proteins.Based on recent examples, we illustrate how individual calcium sensors from the calcium-dependent protein kinase (CPK and calmodulin-like protein (CML families can integrate inputs from various environmental changes. Focusing on members of these two families, shown to be involved in plant responses to both abiotic and biotic stimuli, we discuss their role as key hubs and we put forward hypotheses explaining how they can drive the signalling pathways towards the appropriate plant responses.

  17. Growth, biomass production and ions accumulation in Atriplex nummularia Lindl grown under abiotic stress

    Directory of Open Access Journals (Sweden)

    Hidelblandi F. de Melo

    2016-02-01

    Full Text Available ABSTRACT Atriplex nummularia is a halophyte of great importance in the recovery of saline soils and is considered as a model plant to study biosaline scenarios. This study aimed to evaluate biometric parameters, biomass production and the accumulation of ions in A. nummularia grown under abiotic stresses. Cultivation was carried out in a Fluvic Neosol for 100 days, adopting two water regimes: 37 and 70% of field capacity. Plants were irrigated with saline solutions containing two types of salts (NaCl and a mixture of NaCl, KCl, MgCl2 and CaCl2 at six levels of electrical conductivity: 0, 5, 10, 20, 30 and 40 dS m-1, arranged in a 6 x 2 x 2 factorial with 4 replicates, forming 96 plots. At the end of the experiment, plants were divided into leaves, stem and roots, for the determination of fresh matter (FM, dry matter (DM and estimated leaf area (LA, besides the contents of Ca2+, Mg2+, Na+, K+ and Cl-. The type of salt did not influence plant growth or biomass production; however, it influenced the levels of Ca2+, Mg2+, Na+ and Cl- in the leaves and Mg2+, K+ and Cl- in the roots. Increase in salinity reduced the contents of Ca2+, Mg2+, Na+, K+ and Cl- for all treatments.

  18. ZmLEA3, a multifunctional group 3 LEA protein from maize (Zea mays L.), is involved in biotic and abiotic stresses.

    Science.gov (United States)

    Liu, Yang; Wang, Li; Xing, Xin; Sun, Liping; Pan, Jiaowen; Kong, Xiangpei; Zhang, Maoying; Li, Dequan

    2013-06-01

    Late embryogenesis abundant (LEA) proteins accumulate to high levels during the late stage of seed maturation and in response to water deficit, and are involved in protecting higher plants from damage caused by environmental stresses, especially drought. In the present study, a novel maize (Zea mays L.) group 3 LEA gene, ZmLEA3, was identified and later characterized using transgenic tobacco plants to investigate its functions in abiotic and biotic stresses. Transcript accumulation demonstrated that ZmLEA3 was induced in leaves by high salinity, low temperature, osmotic and oxidative stress as well as by signaling molecules such as ABA, salicylic acid (SA) and methyl jasmonate (MeJA). The transcript of ZmLEA3 could also be induced by pathogens [Pseudomonas syringae pv. tomato DC3000 (pst dc3000)]. ZmLEA3 is located in the cytosol and the nucles. Further study indicated that the ZmLEA3 protein could bind Mn(2+), Fe(3+), Cu(2+) and Zn(2+). Overexpression of ZmLEA3 in transgenic tobacco (Nicotiana tabacum) and yeast (GS115) conferred tolerance to osmotic and oxidative stresses. Interestingly, we also found that overexpression of ZmLEA3 in transgenic tobacco increased the hypersensitive cell death triggered by pst dc3000 and enhanced the expression of PR1a, PR2 and PR4 when compared with the wild type. Thus, we proposed that the ZmLEA3 protein plays a role in protecting plants from damage by protecting protein structure and binding metals under osmotic and oxidative stresses. In addition, ZmLEA3 may also enhance transgenic plant tolerance to biotic stress.

  19. Effects of Abiotic and Biotic Stresses on the Internalization and Dissemination of Human Norovirus Surrogates in Growing Romaine Lettuce.

    Science.gov (United States)

    DiCaprio, Erin; Purgianto, Anastasia; Li, Jianrong

    2015-07-01

    Human norovirus (NoV) is the major causative agent of fresh-produce-related outbreaks of gastroenteritis; however, the ecology and persistence of human NoV in produce systems are poorly understood. In this study, the effects of abiotic and biotic stresses on the internalization and dissemination of two human NoV surrogates (murine norovirus 1 [MNV-1] and Tulane virus [TV]) in romaine lettuce were determined. To induce abiotic stress, romaine lettuce was grown under drought and flood conditions that mimic extreme weather events, followed by inoculation of soil with MNV-1 or TV. Independently, lettuce plants were infected with lettuce mosaic virus (LMV) to induce biotic stress, followed by inoculation with TV. Plants were grown for 14 days, and viral titers in harvested tissues were determined by plaque assays. It was found that drought stress significantly decreased the rates of both MNV-1 and TV internalization and dissemination. In contrast, neither flood stress nor biotic stress significantly impacted viral internalization or dissemination. Additionally, the rates of TV internalization and dissemination in soil-grown lettuce were significantly higher than those for MNV-1. Collectively, these results demonstrated that (i) human NoV surrogates can be internalized via roots and disseminated to shoots and leaves of romaine lettuce grown in soil, (ii) abiotic stress (drought) but not biotic stress (LMV infection) affects the rates of viral internalization and dissemination, and (iii) the type of virus affects the efficiency of internalization and dissemination. This study also highlights the need to develop effective measures to eliminate internalized viruses in fresh produce.

  20. Microarray meta-analysis focused on the response of genes involved in redox homeostasis to diverse abiotic stresses in rice

    Directory of Open Access Journals (Sweden)

    Joao eBraga De Abreu Neto

    2016-01-01

    Full Text Available Plants are exposed to a wide range of abiotic stresses, which often occur in combination. Because physiological investigations typically focus on one stress, our understanding of unspecific stress responses remains limited. The plant redox homeostasis, i.e. the production and removal of reactive oxygen species (ROS, may be involved in many environmental stress conditions. Therefore, this study intended to identify genes, which are activated in diverse abiotic stresses, focusing on ROS–related pathways. We conducted a meta-analysis (MA of microarray experiments, focusing on rice. Transcriptome data were mined from public databases and fellow researchers, which represented 36 different experiments and investigated diverse abiotic stresses, including ozone stress, drought, heat, cold, salinity, and mineral deficiencies/toxicities. To overcome the inherent artefacts of different MA methods, data were processed using Fisher, rOP, REM and product of rank (GeneSelector, and genes identified by most approaches were considered as shared differentially expressed genes (DEGs. Two MA strategies were adopted: first, datasets were separated into shoot, root and seedling experiments, and these tissues were analyzed separately to identify shared DEGs. Second, shoot and seedling experiments were classed into oxidative stress (OS, i.e. ozone and hydrogen peroxide treatments directly producing ROS in plant tissue, and other abiotic stresses (AS, in which ROS production is indirect. In all tissues and stress conditions, genes a priori considered as ROS-related were overrepresented among the DEGs, as they represented 4% of all expressed genes but 7-10% of the DEGs. The combined MA approach was substantially more conservative than individual MA methods and identified 1001 shared DEGs in shoots, 837 shared DEGs in root, and 1172 shared DEGs in seedlings. Within the OS and AS groups, 990 and 1727 shared DEGs were identified, respectively. In total, 311 genes were

  1. A stress-associated NAC transcription factor (SlNAC35) from tomato plays a positive role in biotic and abiotic stresses.

    Science.gov (United States)

    Wang, Guodong; Zhang, Song; Ma, Xiaocui; Wang, Yong; Kong, Fanying; Meng, Qingwei

    2016-09-01

    The NAC transcription factor family participates in responses to various kinds of environmental stimuli in plants. Responses of NAC genes to abiotic stresses have been widely studied, but their functions in response to biotic stress are little reported in plants, especially in crops. In the present study, we examined the functions of a novel tomato (Solanum lycopersicum) NAC protein (SlNAC35) in abiotic and biotic stress resistance by using transgenic tobacco. Expression analysis found that SlNAC35 expression was induced by drought stress, salt stress, bacterial pathogen, and signaling molecules, suggesting its involvement in plant responses to biotic and abiotic stimuli. Moreover, transgenic lines exhibited a greater number of lateral roots and longer root length compared with Vec lines (empty vector lines) after drought and salt treatment. These results indicate that overexpression of SlNAC35 promoted root growth and development under drought and salt stresses. Higher expressions of NtARF1, NtARF2 and NtARF8 were observed under drought and salt stresses in transgenic lines, suggesting that overexpression of SlNAC35 promoted growth and development of roots in transgenic lines possibly by involving auxin signaling and by regulating NtARF expression. In addition, SlNAC35 overexpression improved resistance to bacterial pathogen in transgenic tobacco, and reactive oxygen species may be in the upstream of salicylic acid (SA) signaling in transgenic tobacco during defense response.

  2. Rice Mitogen-activated Protein Kinase Gene Family and Its Role in Biotic and Abiotic Stress Response

    Institute of Scientific and Technical Information of China (English)

    Jai S. Rohila; Yinong Yang

    2007-01-01

    The mitogen-activated protein kinase (MARK) cascade is an important signaling module that transduces extracellular stimuli into intracellular responses in eukaryotic organisms. An increasing body of evidence has shown that the MAPK-mediated cellular signaling is crucial to plant growth and development, as well as biotic and abiotic stress responses. To date, a total of 17 MARK genes have been identified from the rice genome. Expression profiling, biochemical characterization and/or functional analysis were carried out with many members of the rice MARK gene family, especially those associated with biotic and abiotic stress responses. In this review, the phylogenetic relationship and classification of rice MARK genes are discussed to facilitate a simple nomenclature and standard annotation of the rice MARK gene family. Functional data relating to biotic and abiotic stress responses are reviewed for each MARK group and show that despite overlapping in functionality, there is a certain level of functional specificity among different rice MAP kinases. The future challenges are to functionally characterize each MARK, to identify their downstream substrates and upstream kinases, and to genetically manipulate the MARK signaling pathway in rice crops for the improvement of agronomically important traits.

  3. Emerging Importance of Helicases in Plant Stress Tolerance: Characterization of Oryza sativa Repair Helicase XPB2 Promoter and Its Functional Validation in Tobacco under Multiple Stresses.

    Science.gov (United States)

    Raikwar, Shailendra; Srivastava, Vineet K; Gill, Sarvajeet S; Tuteja, Renu; Tuteja, Narendra

    2015-01-01

    Genetic material always remains at the risk of spontaneous or induced damage which challenges the normal functioning of DNA molecule, thus, DNA repair is vital to protect the organisms against genetic damage. Helicases, the unique molecular motors, are emerged as prospective molecules to engineer stress tolerance in plants and are involved in nucleic acid metabolism including DNA repair. The repair helicase, XPB is an evolutionary conserved protein present in different organisms, including plants. Availability of few efficient promoters for gene expression in plants provoked us to study the promoter of XPB for better understanding of gene regulation under stress conditions. Here, we report the in silico analysis of novel stress inducible promoter of Oryza sativa XPB2 (OsXPB2). The in vivo validation of functionality/activity of OsXPB2 promoter under abiotic and hormonal stress conditions was performed by Agrobacterium-mediated transient assay in tobacco leaves using OsXPB2::GUS chimeric construct. The present research revealed that OsXPB2 promoter contains cis-elements accounting for various abiotic stresses (salt, dehydration, or cold) and hormone (Auxin, ABA, or MeJA) induced GUS expression/activity in the promoter-reporter assay. The promoter region of OsXPB2 contains CACG, GTAACG, CACGTG, CGTCA CCGCCGCGCT cis acting-elements which are reported to be salt, dehydration, cold, MeJA, or ABA responsive, respectively. Functional analysis was done by Agrobacterium-mediated transient assay using agroinfiltration in tobacco leaves, followed by GUS staining and fluorescence quantitative analyses. The results revealed high induction of GUS activity under multiple abiotic stresses as compared to mock treated control. The present findings suggest that OsXPB2 promoter is a multi-stress inducible promoter and has potential applications in sustainable crop production under abiotic stresses by regulating desirable pattern of gene expression.

  4. Overexpression of osmotin gene confers tolerance to salt and drought stresses in transgenic tomato (Solanum lycopersicum L.).

    Science.gov (United States)

    Goel, D; Singh, A K; Yadav, V; Babbar, S B; Bansal, K C

    2010-09-01

    Abiotic stresses, especially salinity and drought, are major limiting factors for plant growth and crop productivity. In an attempt to develop salt and drought tolerant tomato, a DNA cassette containing tobacco osmotin gene driven by a cauliflower mosaic virus 35S promoter was transferred to tomato (Solanum lycopersicum) via Agrobacterium-mediated transformation. Putative T0 transgenic plants were screened by PCR analysis. The selected transformants were evaluated for salt and drought stress tolerance by physiological analysis at T1 and T2 generations. Integration of the osmotin gene in transgenic T1 plants was verified by Southern blot hybridization. Transgenic expression of the osmotin gene was verified by RT-PCR and northern blotting in T1 plants. T1 progenies from both transformed and untransformed plants were tested for salt and drought tolerance by subjecting them to different levels of NaCl stress and by withholding water supply, respectively. Results from different physiological tests demonstrated enhanced tolerance to salt and drought stresses in transgenic plants harboring the osmotin gene as compared to the wild-type plants. The transgenic lines showed significantly higher relative water content, chlorophyll content, proline content, and leaf expansion than the wild-type plants under stress conditions. The present investigation clearly shows that overexpression of osmotin gene enhances salt and drought stress tolerance in transgenic tomato plants.

  5. Auxin and its transport play a role in plant tolerance to arsenite-induced oxidative stress in Arabidopsis thaliana.

    Science.gov (United States)

    Krishnamurthy, Aparna; Rathinasabapathi, Bala

    2013-10-01

    The role of auxin in plant development is well known; however, its possible function in root response to abiotic stress is poorly understood. In this study, we demonstrate a novel role of auxin transport in plant tolerance to oxidative stress caused by arsenite. Plant response to arsenite [As(III)] was evaluated by measuring root growth and markers for stress on seedlings treated with control or As(III)-containing medium. Auxin transporter mutants aux1, pin1 and pin2 were significantly more sensitive to As(III) than the wild type (WT). Auxin transport inhibitors significantly reduced plant tolerance to As(III) in the WT, while exogenous supply of indole-3-acetic acid improved As(III) tolerance of aux1 and not that of WT. Uptake assays using H(3) -IAA showed As(III) affected auxin transport in WT roots. As(III) increased the levels of H2 O2 in WT but not in aux1, suggesting a positive role for auxin transport through AUX1 on plant tolerance to As(III) stress via reactive oxygen species (ROS)-mediated signalling. Compared to the WT, the mutant aux1 was significantly more sensitive to high-temperature stress and salinity, also suggesting auxin transport influences a common element shared by plant tolerance to arsenite, salinity and high-temperature stress.

  6. Ionomic profiling of Nicotiana langsdorffii wild-type and mutant genotypes exposed to abiotic stresses.

    Science.gov (United States)

    Ardini, Francisco; Soggia, Francesco; Abelmoschi, Maria Luisa; Magi, Emanuele; Grotti, Marco

    2013-01-01

    To provide a new insight into the response of plants to abiotic stresses, the ionomic profiles of Nicotiana langsdorffii specimens have been determined before and after exposure to toxic metals (chromium) or drought conditions. The plants were genetically transformed with the rat glucocorticoid receptor (GR) or the gene for Agrobacterium rhizogenes rolC, because these modifications are known to produce an imbalance in phytohormone equilibria and a significant change in the defence response of the plant. Elemental profiles were obtained by developing and applying analytical procedures based on inductively coupled plasma atomic emission and mass spectrometry (ICP-AES/MS). In particular, the removal of isobaric interferences affecting the determination of Cr and V by ICP-MS was accomplished by use of a dynamic reaction cell, after optimization of the relevant conditions. The combined use of ICP atomic emission and mass spectrometry enabled the determination of 29 major and trace elements (Ba, Bi, Ca, Cd, Co, Cr, Cu, Eu, Fe, Ga, K, Li, Mg, Mn, Mo, Na, P, Pb, Pt, Rb, S, Sb, Sn, Sr, Te, V, W, Y, and Zn) in different parts of the plants (roots, stems, and leaves), with high accuracy and precision. Multivariate data processing and study of element distribution patterns provided new information about the ionomic response of the target organism to chemical treatment or water stress. Genetic modification mainly affected the distribution of Bi, Cr, Mo, Na, and S, indicating that these elements were involved in biochemical processes controlled by the GR or rolC genes. Chemical stress strongly affected accumulation of several elements (Ba, Ca, Fe, Ga, K, Li, Mn, Mo, Na, P, Pb, Rb, S, Sn, Te, V, and Zn) in different ways; for Ca, Fe, K, Mn, Na, and P the effect was quite similar to that observed in other studies after treatment with other transition elements, for example Cu and Cd. The effect of water deficit was less evident, mainly consisting in a decrease of Ba, Cr, Na, and Sr

  7. Pea p68, a DEAD-box helicase, provides salinity stress tolerance in transgenic tobacco by reducing oxidative stress and improving photosynthesis machinery.

    Directory of Open Access Journals (Sweden)

    Narendra Tuteja

    Full Text Available BACKGROUND: The DEAD-box helicases are required mostly in all aspects of RNA and DNA metabolism and they play a significant role in various abiotic stresses, including salinity. The p68 is an important member of the DEAD-box proteins family and, in animal system, it is involved in RNA metabolism including pre-RNA processing and splicing. In plant system, it has not been well characterized. Here we report the cloning and characterization of p68 from pea (Pisum sativum and its novel function in salinity stress tolerance in plant. RESULTS: The pea p68 protein self-interacts and is localized in the cytosol as well as the surrounding of cell nucleus. The transcript of pea p68 is upregulated in response to high salinity stress in pea. Overexpression of p68 driven by constitutive cauliflower mosaic virus-35S promoter in tobacco transgenic plants confers enhanced tolerances to salinity stress by improving the growth, photosynthesis and antioxidant machinery. Under stress treatment, pea p68 overexpressing tobacco accumulated higher K+ and lower Na+ level than the wild-type plants. Reactive oxygen species (ROS accumulation was remarkably regulated by the overexpression of pea p68 under salinity stress conditions, as shown from TBARS content, electrolyte leakage, hydrogen peroxide accumulation and 8-OHdG content and antioxidant enzyme activities. CONCLUSIONS: To the best of our knowledge this is the first direct report, which provides the novel function of pea p68 helicase in salinity stress tolerance. The results suggest that p68 can also be exploited for engineering abiotic stress tolerance in crop plants of economic importance.

  8. The LysM Receptor-Like Kinase LysM RLK1 Is Required to Activate Defense and Abiotic-Stress Responses Induced by Overexpression of Fungal Chitinases in Arabidopsis Plants

    Institute of Scientific and Technical Information of China (English)

    Yariv Brotman; Ada Viterbo; Udi Landau; Smadar Pnini; Jan Lisec; Salma Balazadeh; Bernd Mueller-Roeber; Aviah Zilberstein; Lothar Willmitzer; Ilan Chet

    2012-01-01

    Application of crab shell chitin or pentamer chitin oligosaccharide to Arabidopsis seedlings increased tolerance to salinity in wild-type but not in knockout mutants of the LysM Receptor-Like Kinase1 (CERK1/LysM RLK1) gene,known to play a critical role in signaling defense responses induced by exogenous chitin.Arabidopsis plants overexpressing the endochitinase chit36 and hexoaminidase excy1 genes from the fungus Trichoderma asperelleoides T203 showed increased tolerance to salinity,heavy-metal stresses,and Botrytis cinerea infection.Resistant lines,overexpressing fungal chitinases at different levels,were outcrossed to lysm rlk1 mutants.Independent homozygous hybrids lost resistance to biotic and abiotic stresses,despite enhanced chitinase activity.Expression analysis of 270 stress-related genes,including those induced by reactive oxygen species (ROS) and chitin,revealed constant up-regulation (at least twofold) of 10 genes in the chitinase-overexpressing line and an additional 76 salt-induced genes whose expression was not elevated in the lysm rlk1 knockout mutant or the hybrids harboring the mutation.These findings elucidate that chitin-induced signaling mediated by LysM RLK1 receptor is not limited to biotic stress response but also encompasses abiotic-stress signaling and can be conveyed by ectopic expression of chitinases in plants.

  9. The tomato DWD motif-containing protein DDI1 interacts with the CUL4–DDB1-based ubiquitin ligase and plays a pivotal role in abiotic stress responses

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Min [Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064 (China); School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009 (China); Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339 (United States); Zhu, Yunye [School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009 (China); Qiao, Maiju [Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064 (China); Tang, Xiaofeng [Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064 (China); School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009 (China); Zhao, Wei [School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009 (China); Xiao, Fangming [Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339 (United States); Liu, Yongsheng, E-mail: liuyongsheng1122@hfut.edu.cn [Ministry of Education Key Laboratory for Bio-resource and Eco-environment, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064 (China); School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009 (China)

    2014-08-08

    Highlights: • We identify DDI1 as a DAMAGED DNA BINDING PROTEIN1 (DDB1)-interacting protein. • DDI1 interacts with the CUL4–DDB1-based ubiquitin ligase in the nucleus. • DDI1 plays a positive role in regulating abiotic stress response in tomato. - Abstract: CULLIN4(CUL4)–DAMAGED DNA BINDING PROTEIN1 (DDB1)-based ubiquitin ligase plays significant roles in multiple physiological processes via ubiquitination-mediated degradation of relevant target proteins. The DDB1–CUL4-associated factor (DCAF) acts as substrate receptor in the CUL4–DDB1 ubiquitin ligase complex and determines substrate specificity. In this study, we identified a tomato (Solanum lycopersicum) DDB1-interacting (DDI1) protein as a DCAF protein involved in response to abiotic stresses, including UV radiation, high salinity and osmotic stress. Co-immunoprecipitation and bimolecular fluorescence complementation assay indicated that DDI1 associates with CUL4–DDB1 in the nucleus. Quantitative RT-PCR analysis indicated the DDI1 gene is induced by salt, mannitol and UV-C treatment. Moreover, transgenic tomato plants with overexpression or knockdown of the DDI1 gene exhibited enhanced or attenuated tolerance to salt/mannitol/UV-C, respectively. Thus, our data suggest that DDI1 functions as a substrate receptor of the CUL4–DDB1 ubiquitin ligase, positively regulating abiotic stress response in tomato.

  10. Spatial metabolic fingerprinting using FT-IR spectroscopy: investigating abiotic stresses on Micrasterias hardyi.

    Science.gov (United States)

    Patel, Soyab A; Currie, Felicity; Thakker, Nalin; Goodacre, Royston

    2008-12-01

    The release of active pharmaceutical ingredients (APIs) into the environment is an ecologically important topic for study because, whilst APIs have been designed to have a wide range of biological properties for the target of interest (usually in man), little information on potential ecological risks is currently available regarding their effects on the organisms that inhabit the environment. In this study, the algae Micrasterias hardyi was exposed to propranolol, metoprolol (beta-adrenergic receptor agonist drugs) and mefenamic acid (a non steroidal anti-inflammatory drug), at concentrations ranging between 0.002-0.2 mM. Initial studies showed that Fourier transform infrared (FT-IR) spectroscopy on algal homogenates illustrated that all three APIs had a quantitative effect on the metabolism of the organisms and it was possible to estimate the level of API exposure from the FT-IR metabolic fingerprints using partial least squares (PLS) regression. From the inspection of the PLS loadings matrices it was possible to elucidate that all drugs caused effects on protein and lipid levels. Most strikingly propranolol had significant effects on the lipid components of the cell. These were dramatically reduced possibly as a consequence of loss of membrane integrity. In order to investigate this further, FT-IR microspectroscopy was used to generate detailed metabolic fingerprinting maps. These chemical maps revealed that all the drugs had a dramatic effect on the distribution of various chemical species throughout the algae, and that all drugs had an affect on protein and lipid levels. In particular, as noted in the PLS analyses for propranolol treated cells, the lipid complement found in the lipid storage areas in the processes of M. hardyi was greatly reduced. This illustrates the power of spatial metabolic fingerprinting for investigating abiotic stresses on complex biological species.

  11. Stress tolerant crops from nitrogen fixing trees

    Energy Technology Data Exchange (ETDEWEB)

    Becker, R.; Saunders, R.M.

    1983-01-01

    Notes are given on the nutritional quality and uses of: pods of Geoffroea decorticans, a species tolerant of saline and limed soils and saline water; seeds of Olneya tesota which nodulates readily and fixes nitrogen and photosynthesizes at low water potential; and pods of Prosopis chilensis and P. tamarugo which tolerate long periods without rain. 3 references.

  12. SpUSP, an annexin-interacting universal stress protein, enhances drought tolerance in tomato.

    Science.gov (United States)

    Loukehaich, Rachid; Wang, Taotao; Ouyang, Bo; Ziaf, Khurram; Li, Hanxia; Zhang, Junhong; Lu, Yongen; Ye, Zhibiao

    2012-09-01

    Universal stress protein (USP) appears to play an active role in the abiotic stress response, but their functions remain largely unknown in plants. A USP gene (SpUSP) was cloned from wild tomato (Solanum pennellii) and functionally characterized in cultivated tomato in the present study. The SpUSP transcript is abundantly accumulated in leaf stomata and its expression varied with the circadian rhythm. SpUSP was remarkably induced by dehydration, salt stress, oxidative stress, and the phytohormone abscisic acid (ABA) etc. This protein was predominantly localized in the nucleus and cell membrane. Overexpressing SpUSP increased drought tolerance of tomato in the seedling and adult stages. Under drought stress, the ABA content significantly increased in the SpUSP-overexpressing plants, which induced stomatal closure and reduced water loss, leading to the enhancement of drought tolerance. Based on the microarray data, a large number of chlorophyll a/b-binding proteins and photosystem-related genes were up-regulated in the SpUSP-overexpressing plants under drought conditions, which possibly enhanced the stomatal sensivitity to ABA and maintained the photosynthetic function. SpUSP overexpression also alleviated the oxidative damage accompanied by oxidative stress-responsive gene activation and osmolyte accumulation. Annexin (SGN-U314161) was found to interacte with SpUSP in the yeast two-hybrid method. This interaction was further confirmed by the bimolecular fluorescence complementation assay. The present study demonstrated that the annexin-interacting SpUSP plays important roles in the drought tolerance of tomato by influencing ABA-induced stomatal movement, increasing photosynthesis, and alleviating oxidative stress.

  13. Global expression profiling of rice microRNAs by one-tube stem-loop reverse transcription quantitative PCR revealed important roles of microRNAs in abiotic stress responses.

    Science.gov (United States)

    Shen, Jianqiang; Xie, Kabin; Xiong, Lizhong

    2010-12-01

    MicroRNAs are a class of endogenous small RNA molecules (20-24 nucleotides) that have pivotal roles in regulating gene expression mostly at posttranscriptional levels in plants. Plant microRNAs have been implicated in the regulation of diverse biological processes including growth and stress responses. However, the information about microRNAs in regulating abiotic stress responses in rice is limited. We optimized a one-tube stem-loop reverse transcription quantitative PCR (ST-RT qPCR) for high-throughput expression profiling analysis of microRNAs in rice under normal and stress conditions. The optimized ST-RT qPCR method was as accurate as small RNA gel blotting and was more convenient and time-saving than other methods in quantifying microRNAs. With this method, 41 rice microRNAs were quantified for their relative expression levels after drought, salt, cold, and abscisic acid (ABA) treatments. Thirty-two microRNAs showed induced or suppressed expression after stress or ABA treatment. Further analysis suggested that stress-responsive cis-elements were enriched in the promoters of stress-responsive microRNA genes. The expressions of five and seven microRNAs were significantly affected in the rice plant with defects in stress tolerance regulatory genes OsSKIPa and OsbZIP23, respectively. Some of the predicted target genes of these microRNAs were also related to abiotic stresses. We conclude that ST-RT qPCR is an efficient and reliable method for expression profiling of microRNAs and a significant portion of rice microRNAs participate in abiotic stress response and regulation.

  14. Evidence for a role of gibberellins in salicylic acid-modulated early plant responses to abiotic stress in Arabidopsis seeds.

    Science.gov (United States)

    Alonso-Ramírez, Ana; Rodríguez, Dolores; Reyes, David; Jiménez, Jesús Angel; Nicolás, Gregorio; López-Climent, María; Gómez-Cadenas, Aurelio; Nicolás, Carlos

    2009-07-01

    Exogenous application of gibberellic acid (GA(3)) was able to reverse the inhibitory effect of salt, oxidative, and heat stresses in the germination and seedling establishment of Arabidopsis (Arabidopsis thaliana), this effect being accompanied by an increase in salicylic acid (SA) levels, a hormone that in recent years has been implicated in plant responses to abiotic stress. Furthermore, this treatment induced an increase in the expression levels of the isochorismate synthase1 and nonexpressor of PR1 genes, involved in SA biosynthesis and action, respectively. In addition, we proved that transgenic plants overexpressing a gibberellin (GA)-responsive gene from beechnut (Fagus sylvatica), coding for a member of the GA(3) stimulated in Arabidopsis (GASA) family (FsGASA4), showed a reduced GA dependence for growth and improved responses to salt, oxidative, and heat stress at the level of seed germination and seedling establishment. In 35S:FsGASA4 seeds, the improved behavior under abiotic stress was accompanied by an increase in SA endogenous levels. All these data taken together suggest that this GA-responsive gene and exogenous addition of GAs are able to counteract the inhibitory effects of these adverse environmental conditions in seed germination and seedling growth through modulation of SA biosynthesis. Furthermore, this hypothesis is supported by the fact that sid2 mutants, impaired in SA biosynthesis, are more sensitive to salt stress than wild type and are not affected by exogenous application of GA(3).

  15. Role of miRNAs and siRNAs in biotic and abiotic stress responses of plants

    KAUST Repository

    Khraiwesh, Basel

    2012-02-01

    Small, non-coding RNAs are a distinct class of regulatory RNAs in plants and animals that control a variety of biological processes. In plants, several classes of small RNAs with specific sizes and dedicated functions have evolved through a series of pathways. The major classes of small RNAs include microRNAs (miRNAs) and small interfering RNAs (siRNAs), which differ in their biogenesis. miRNAs control the expression of cognate target genes by binding to reverse complementary sequences, resulting in cleavage or translational inhibition of the target RNAs. siRNAs have a similar structure, function, and biogenesis as miRNAs but are derived from long double-stranded RNAs and can often direct DNA methylation at target sequences. Besides their roles in growth and development and maintenance of genome integrity, small RNAs are also important components in plant stress responses. One way in which plants respond to environmental stress is by modifying their gene expression through the activity of small RNAs. Thus, understanding how small RNAs regulate gene expression will enable researchers to explore the role of small RNAs in biotic and abiotic stress responses. This review focuses on the regulatory roles of plant small RNAs in the adaptive response to stresses. This article is part of a Special Issue entitled: Plant gene regulation in response to abiotic stress. © 2011 Elsevier B.V.

  16. Mapping regulatory genes as candidates for cold and drought stress tolerance in barley.

    Science.gov (United States)

    Tondelli, A; Francia, E; Barabaschi, D; Aprile, A; Skinner, J S; Stockinger, E J; Stanca, A M; Pecchioni, N

    2006-02-01

    Cereal crop yield is greatly affected in many growing areas by abiotic stresses, mainly low temperature and drought. In order to find candidates for the tolerance genes for these stresses, 13 genes encoding for transcription factors and upstream regulators were screened by amplification and SSCP on six parental genotypes of three barley mapping populations ('Nure' x 'Tremois', 'Proctor' x 'Nudinka', and 'Steptoe' x 'Morex'), and mapped as newly developed STS, SNP, and SSCP markers. A new consensus function map was then drawn using the three maps above, including 16 regulatory candidate genes (CGs). The positions of barley cold and drought tolerance quantitative trait loci (QTLs) presently described in the literature were added to the consensus map to find positional candidates from among the mapped genes. A cluster of six HvCBF genes co-mapped with the Fr-H2 cold tolerance QTL, while no QTLs for the same trait were positioned on chromosome 7H, where two putative barley regulators of CBF expression, ICE1 and FRY1, found by homology search, were mapped in this work. These observations suggest that CBF gene(s) themselves, rather than their two regulators, are at present the best candidates for cold tolerance. Four out of 12 drought tolerance QTLs of the consensus map are associated with regulatory CGs, on chromosomes 2H, 5H, and 7H, and two QTLs with effector genes, on chromosomes 5H and 6H. The results obtained could be used to guide MAS applications, allowing introduction into an ideal genotype of favourable alleles of tolerance QTLs.

  17. Whole-genome identiifcation and expression analysis of K+eflfux antiporter (KEA) and Na+/H+antiporter (NHX) families under abiotic stress in soybean

    Institute of Scientific and Technical Information of China (English)

    CHEN Hua-tao; CHEN Xin; WU Bing-yue; YUAN Xing-xing; ZHANG Hong-mei; CUI Xiao-yan; LIU Xiao-qing

    2015-01-01

    Sodium toxicity and potassium insufifcient are important factors affecting the growth and development of soybean in saline soil. As the capacity of plants to maintain a high cytosolic, K+/Na+ratio is the key determinant of tolerance under salt stress. The aims of the present study were to identify and analyse expression patterns of the soybean K+eflfux antiporter (KEA) gene and Na+/H+ antiporter (NHX) gene family, and to explore their roles under abiotic stress. As a result, 12 soybean GmKEAs genes and 10 soybean GmNHXs genes were identiifed and analyzed from soybean genome. Interestingly, the novel soybean KEA gene Glyma16g32821 which encodes 11 transmembrane domains were extremely up-regulated and remained high level until 48 h in root after the excessive potassium treatment and lack of potassium treatment, respectively. The novel soybean NHX gene Glyma09g02130 which encodes 10 transmembrane domains were extremely up-regulated and remained high level until 48 h in root with NaCl stress. Imaging of subcel ular locations of the two new Glyma16g32821-GFP and Glyma09g02130-GFP fusion proteins indicated al plasma membrane localizations of the two novel soybean genes. The 3D structures indicated that the two soybean novel proteins Glyma09g02130 (NHX) and Glyma16g32821 (KEA) al belong to the cation/hydrogen antiporter family.

  18. Improvement of Salinity Stress Tolerance in Rice: Challenges and Opportunities

    Directory of Open Access Journals (Sweden)

    Thi My Linh Hoang

    2016-10-01

    Full Text Available Rice (Oryza sativa L. is an important staple crop that feeds more than one half of the world’s population and is the model system for monocotyledonous plants. However, rice is very sensitive to salinity and is the most salt sensitive cereal crop with a threshold of 3 dSm−1 for most cultivated varieties. Despite many attempts using different strategies to improve salinity tolerance in rice, the achievements so far are quite modest. This review aims to discuss challenges that hinder the improvement of salinity stress tolerance in rice as well as potential opportunities for enhancing salinity stress tolerance in this important crop.

  19. Improved Alkane Production in Nitrogen-Fixing and Halotolerant Cyanobacteria via Abiotic Stresses and Genetic Manipulation of Alkane Synthetic Genes.

    Science.gov (United States)

    Kageyama, Hakuto; Waditee-Sirisattha, Rungaroon; Sirisattha, Sophon; Tanaka, Yoshito; Mahakhant, Aparat; Takabe, Teruhiro

    2015-07-01

    Cyanobacteria possess the unique capacity to produce alkane. In this study, effects of nitrogen deficiency and salt stress on biosynthesis of alkanes were investigated in three kinds of cyanobacteria. Intracellular alkane accumulation was increased in nitrogen-fixing cyanobacterium Anabaena sp. PCC7120, but decreased in non-diazotrophic cyanobacterium Synechococcus elongatus PCC7942 and constant in a halotolerant cyanobacterium Aphanothece halophytica under nitrogen-deficient condition. We also found that salt stress increased alkane accumulation in Anabaena sp. PCC7120 and A. halophytica. The expression levels of two alkane synthetic genes were not upregulated significantly under nitrogen deficiency or salt stress in Anabaena sp. PCC7120. The transformant Anabaena sp. PCC7120 cells with additional alkane synthetic gene set from A. halophytica increased intracellular alkane accumulation level compared to control cells. These results provide a prospect to improve bioproduction of alkanes in nitrogen-fixing halotolerant cyanobacteria via abiotic stresses and genetic engineering.

  20. Selection of Reliable Reference Genes for Gene Expression Analysis under Abiotic Stresses in the Desert Biomass Willow, Salix psammophila.

    Science.gov (United States)

    Li, Jianbo; Jia, Huixia; Han, Xiaojiao; Zhang, Jin; Sun, Pei; Lu, Mengzhu; Hu, Jianjun

    2016-01-01

    Salix psammophila is a desert shrub willow that has extraordinary adaptation to abiotic stresses and plays an important role in maintaining local ecosystems. Moreover, S. psammophila is regarded as a promising biomass feedstock because of its high biomass yields and short rotation coppice cycle. However, few suitable reference genes (RGs) for quantitative real-time polymerase chain reaction (qRT-PCR) constrain the study on normalization of gene expression in S. psammophila until now. Here, we investigated the expression stabilities of 14 candidate RGs across tissue types and under four abiotic stress treatments, including heat, cold, salt, and drought treatments. After calculation of PCR efficiencies, three different software, NormFinder, geNorm, and BestKeeper were employed to analyze systematically the qRT-PCR data, and the outputs were merged by RankAggreg software. The optimal RGs selected for gene expression analysis were EF1α (Elongation factor-1 alpha) and OTU (OTU-like cysteine protease family protein) for different tissue types, UBC (Ubiquitin-conjugating enzyme E2) and LTA4H (Leukotriene A-4 hydrolase homolog) for heat treatment, HIS (Histone superfamily protein H3) and ARF2 (ADP-ribosylation factor 2) for cold treatment, OTU and ACT7 (Actin 7) for salt treatment, UBC and LTA4H for drought treatment. The expression of UBC, ARF2, and VHAC (V-type proton ATPase subunit C) varied the least across tissue types and under abiotic stresses. Furthermore, the relative genes expression profiles of one tissue-specific gene WOX1a (WUSCHEL-related homeobox 1a), and four stress-inducible genes, including Hsf-A2 (Heat shock transcription factors A2), CBF3 (C-repeat binding factor 3), HKT1 (High-Affinity K(+) Transporter 1), and GST (Glutathione S-transferase), were conducted to confirm the validity of the RGs in this study. These results provided an important RGs application guideline for gene expression characterization in S. psammophila.

  1. Abiotic stress growth conditions induce different responses in kernel iron concentration across genotypically distinct maize inbred varieties.

    Science.gov (United States)

    Kandianis, Catherine B; Michenfelder, Abigail S; Simmons, Susan J; Grusak, Michael A; Stapleton, Ann E

    2013-01-01

    The improvement of grain nutrient profiles for essential minerals and vitamins through breeding strategies is a target important for agricultural regions where nutrient poor crops like maize contribute a large proportion of the daily caloric intake. Kernel iron concentration in maize exhibits a broad range. However, the magnitude of genotype by environment (GxE) effects on this trait reduces the efficacy and predictability of selection programs, particularly when challenged with abiotic stress such as water and nitrogen limitations. Selection has also been limited by an inverse correlation between kernel iron concentration and the yield component of kernel size in target environments. Using 25 maize inbred lines for which extensive genome sequence data is publicly available, we evaluated the response of kernel iron density and kernel mass to water and nitrogen limitation in a managed field stress experiment using a factorial design. To further understand GxE interactions we used partition analysis to characterize response of kernel iron and weight to abiotic stressors among all genotypes, and observed two patterns: one characterized by higher kernel iron concentrations in control over stress conditions, and another with higher kernel iron concentration under drought and combined stress conditions. Breeding efforts for this nutritional trait could exploit these complementary responses through combinations of favorable allelic variation from these already well-characterized genetic stocks.

  2. Increased growth in sunflower correlates with reduced defences and altered gene expression in response to biotic and abiotic stress.

    Science.gov (United States)

    Mayrose, Maya; Kane, Nolan C; Mayrose, Itay; Dlugosch, Katrina M; Rieseberg, Loren H

    2011-11-01

    Cultivated plants have been selected by humans for increased yield in a relatively benign environment, where nutrient and water resources are often supplemented, and biotic enemy loads are kept artificially low. Agricultural weeds have adapted to this same benign environment as crops and often have high growth and reproductive rates, even though they have not been specifically selected for yield. Considering the competing demands for resources in any plant, a key question is whether adaptation to agricultural environments has been accompanied by life history trade-offs, in which resistance to (largely absent) stress has been lost in favour of growth and reproduction. The experiments reported here were designed to test for growth-defence trade-offs in agricultural weeds, crops and native varieties of common sunflower (Helianthus annuus L., Asteraceae) by comparing their performance in the presence or absence of abiotic (drought and crowding) or biotic (simulated herbivory, insect herbivory and fungal) stress. We found that growth, as well as viability of crops and weeds, was reduced by abiotic drought stress. The weakened defence in the agricultural genotypes was further evident as increased susceptibility to fungal infection and higher level of insect palatability. To uncover molecular mechanisms underlying these trade-offs, we monitored gene expression kinetics in drought-stressed plants. By correlating phenotypic observations with molecular analyses, we report the identification of several genes, including a protein phosphatase 2C and the HD-Zip transcription factor Athb-8, whose expression is associated with the observed phenotypic variation in common sunflower.

  3. Identification of Festuca arundinacea Schreb Cat1 Catalase Gene and Analysis of its Expression Under Abiotic Stresses

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Abiotic stresses, such as drought, high salinity, and cold/freezing, lead plants to produce excess reactive oxygen species. Catalase, a unique hydrogen peroxide-scavenging enzyme, plays a very important role in plants. To characterize the catalase involved in plant response to abiotic stresses, we constructed a cDNA library from 4 ℃-treated Festuca arundinacea Schreb seedlings and isolated a catalase gene from this library.The cDNA (FaCat1, 1 735 bp) contained an open reading frame of 1 479 bp. BLAST analysis indicated that the deduced amino acid sequence showed 96% identity with that from wheat TaCat1 and 87% identity with that from maize ZmCat2. Northern blotting analysis showed an obvious increase of FaCat1 transcripts in leaves in contrast with roots. Time-course analysis of the expression of FaCat1 in F. arundinacea leaves showed that FaCat1 expression was upregulated in cold- and salt-stressed leaves, with the FaCat1 transcripts accumulating mostly at 4 or 2 h after cold or salt stress, respectively. No significant changes in FaCat1 transcription were observed in dried leaves and inhibition of FaCat1 transcription was found in abscisic acid (ABA)-treated leaves,indicating that the FaCat1 gene is differentially expressed during cold, high salt, drought, and ABA treatment in F. arundinacea leaves.

  4. OsPEX11, a Peroxisomal Biogenesis Factor 11, Contributes to Salt Stress Tolerance in Oryza sativa

    Science.gov (United States)

    Cui, Peng; Liu, Hongbo; Islam, Faisal; Li, Lan; Farooq, Muhammad A.; Ruan, Songlin; Zhou, Weijun

    2016-01-01

    Peroxisomes are single membrane-bound organelles, whose basic enzymatic constituents are catalase and H2O2-producing flavin oxidases. Previous reports showed that peroxisome is involved in numerous processes including primary and secondary metabolism, plant development and abiotic stress responses. However, knowledge on the function of different peroxisome genes from rice and its regulatory roles in salt and other abiotic stresses is limited. Here, a novel prey protein, OsPEX11 (Os03g0302000), was screened and identified by yeast two-hybrid and GST pull-down assays. Phenotypic analysis of OsPEX11 overexpression seedlings demonstrated that they had better tolerance to salt stress than wild type (WT) and OsPEX11-RNAi seedlings. Compared with WT and OsPEX11-RNAi seedlings, overexpression of OsPEX11 had lower level of lipid peroxidation, Na+/K+ ratio, higher activities of antioxidant enzymes (SOD, POD, and CAT) and proline accumulation. Furthermore, qPCR data suggested that OsPEX11 acted as a positive regulator of salt tolerance by reinforcing the expression of several well-known rice transporters (OsHKT2;1, OsHKT1;5, OsLti6a, OsLti6b, OsSOS1, OsNHX1, and OsAKT1) involved in Na+/K+ homeostasis in transgenic plants under salinity. Ultrastructural observations of OsPEX11-RNAi seedlings showed that they were less sensitive to salt stress than WT and overexpression lines. These results provide experimental evidence that OsPEX11 is an important gene implicated in Na+ and K+ regulation, and plays a critical role in salt stress tolerance by modulating the expression of cation transporters and antioxidant defense. Thus, OsPEX11 could be considered in transgenic breeding for improvement of salt stress tolerance in rice crop. PMID:27695459

  5. OsPEX11, a peroxisomal biogenesis factor 11, contributes to salt stress tolerance in Oryza sativa

    Directory of Open Access Journals (Sweden)

    Cui Peng

    2016-09-01

    Full Text Available Peroxisomes are single membrane-bound organelles, whose basic enzymatic constituents are catalase and H2O2-producing flavin oxidases. Previous reports showed that peroxisome is involved in numerous processes including primary and secondary metabolism, plant development and abiotic stress responses. However, knowledge on the function of different peroxisome genes from rice and its regulatory roles in salt and other abiotic stresses is limited. Here, a novel prey protein, OsPEX11 (Os03g0302000, was screened and identified by yeast two-hybrid and GST pull down assays. Phenotypic analysis of OsPEX11 overexpression seedlings demonstrated that they had better tolerance to salt stress than wild type and OsPEX11-RNAi seedlings. Compared with wild type and OsPEX11-RNAi seedlings, overexpression of OsPEX11 had lower level of lipid peroxidation, Na+/K+ ratio, higher activities of antioxidant enzymes (SOD, POD and CAT and proline accumulation. Furthermore, qPCR data suggested that OsPEX11 acted as a positive regulator of salt tolerance by reinforcing the expression of several well-known rice transporters (OsHKT2;1, OsHKT1;5, OsLti6a, OsLti6b, OsSOS1, OsNHX1 and OsAKT1 involved in Na+/K+ homeostasis in transgenic plants under salinity. Ultrastructural observations of OsPEX11-RNAi seedlings showed that they were less sensitive to salt stress than wild type and overexpression lines. These results provide experimental evidence that OsPEX11 is an important gene implicated in Na+ and K+ regulation, and plays a critical role in salt stress tolerance by modulating the expression of cation transporters and antioxidant defense. Thus, OsPEX11 could be considered in transgenic breeding for improvement of salt stress tolerance in rice crop.

  6. Research Progress in Glycine Betaine Improving Plant Salty Stressful Tolerance

    Institute of Scientific and Technical Information of China (English)

    ZHU Hong; WANG Wenjie; YAN Yongqing; ZU Yuangang

    2008-01-01

    Many plants accumulate compatible solutes in response to the imposition of environmental stresses. Glycine betaine, which is one of compatible solutes in cell of plants, has been shown to have surviving ability for plant from salt stress. Effect of glycine betaine on improving plant salt resistance was discussed in plants under salt stress. The accumulation of glycine betaine protects plants against the damaging effects of stress. Strategies of glycine betaine against the damaging effects of stress were analyzed to clarify the roles of glycine betaine in salt stress tolerance of plants.

  7. Application of stress susceptibility index for drought tolerance screening of tomato populations

    Directory of Open Access Journals (Sweden)

    Zdravković Jasmina

    2013-01-01

    Full Text Available Investigation comprised 41 tomato genotypes originating from the population of domestic and domesticated genotypes collected in Serbia and belonging to the tomato collection of the Institute of Vegetable Crop Science, Smederevska Palanka. The aim of collection screening was to choose the genotypes tolerant to drought during plant intensive growth stage, whereby the process of selection would set out to obtain the recombinant genotypes for this abiotic factor. The screening criteria were established for genotype divergence in plant height and shoot-root ratio under conditions of optimal irrigation regime and drought. Divergence was estimated using cluster analysis with Euclidean distance as a measure of distance, with a complete gene attachment to grouping. Drought tolerance is expressed by the stress susceptibility index (SSI. Various results were obtained based on the screening of genotypes grown under optimal and dry conditions. As a measure of stress susceptibility, based on SSI, genotypes having different drought tolerance level were determined. On the grounds of the analyses carried out, 10 genotypes were segregated (G102, G104, G107, G109, G110, G119, G125, G126, G128 and G141 to represent a basis to obtain the recombinant genotypes and to initiate the selection for drought resistance. [Projekat Ministarstva nauke Republike Srbije, br. TR 31005 i br. TR 31059

  8. Native isolate of Trichoderma: a biocontrol agent with unique stress tolerance properties.

    Science.gov (United States)

    Mishra, N; Khan, S S; Sundari, S Krishna

    2016-08-01

    Species of Trichoderma are widely recognized for their biocontrol abilities, but seldom studied collectively, for their plant growth promotion, abiotic stress tolerance and bioremediation properties. Our study is a concentrated effort to establish the potential of native isolate Trichoderma harzianum KSNM (T103) to tolerate biotic (root pathogens) and abiotic stresses [high salt (100-1000 mM); heavy metal (chromium, nickel and zinc: 1-10 mM); pesticides: malathion (100-600 ppm), carbofuran (100-600 ppb)], along with its ability to support plant growth. In vitro growth promotion assays with T103 treated Vigna radiata, Vigna mungo and Hordeum vulgare confirmed 'non-species specific' growth promotion effects of T103. At lower metal concentration, T103 treatment was found to completely negate the impact of metal stress [60 % increase in radicle length (RL) with no significant decrease in %germination (%G)]. Even at 10 mM metal, T103 inoculation gave 80 % increase in %G and >50 % increase in RL. In vitro experiments confirmed high metal reduction capacity (47 %-Cr, 35 %-Ni and 42 %-Zn) of T103 at concentrations as high as 4 mM. At maximum residual concentrations of malathion (440 ppm) and carbofuran (100 ppb) reported in agricultural soils, T103 maintained 80 and 100 % survivability, respectively. T103 treatment has improved %G and RL in all three hosts challenged with pesticide. Isolate T103 was found to effectively suppress growth of three major root pathogens: Macrophomina phaseolina (65.83 %) followed by Sclerotium rolfsii (19.33 %) and Fusarium oxysporum (19.18 %). In the light of these observations, native T. harzianum (T103) seems to be a competent biocontrol agent for tropical agricultural soils contaminated with residual pesticides and heavy metals.

  9. The involvement of wheat F-box protein gene TaFBA1 in the oxidative stress tolerance of plants.

    Directory of Open Access Journals (Sweden)

    Shu-Mei Zhou

    Full Text Available As one of the largest gene families, F-box domain proteins have been found to play important roles in abiotic stress responses via the ubiquitin pathway. TaFBA1 encodes a homologous F-box protein contained in E3 ubiquitin ligases. In our previous study, we found that the overexpression of TaFBA1 enhanced drought tolerance in transgenic plants. To investigate the mechanisms involved, in this study, we investigated the tolerance of the transgenic plants to oxidative stress. Methyl viologen was used to induce oxidative stress conditions. Real-time PCR and western blot analysis revealed that TaFBA1 expression was up-regulated by oxidative stress treatments. Under oxidative stress conditions, the transgenic tobacco plants showed a higher germination rate, higher root length and less growth inhibition than wild type (WT. The enhanced oxidative stress tolerance of the transgenic plants was also indicated by lower reactive oxygen species (ROS accumulation, malondialdehyde (MDA content and cell membrane damage under oxidative stress compared with WT. Higher activities of antioxidant enzymes, including superoxide dismutase (SOD, catalase (CAT, ascorbate peroxidase (APX and peroxidase (POD, were observed in the transgenic plants than those in WT, which may be related to the upregulated expression of some antioxidant genes via the overexpression of TaFBA1. In others, some stress responsive elements were found in the promoter region of TaFBA1, and TaFBA1 was located in the nucleus, cytoplasm and plasma membrane. These results suggest that TaFBA1 plays an important role in the oxidative stress tolerance of plants. This is important for understanding the functions of F-box proteins in plants' tolerance to multiple stress conditions.

  10. The involvement of wheat F-box protein gene TaFBA1 in the oxidative stress tolerance of plants.

    Science.gov (United States)

    Zhou, Shu-Mei; Kong, Xiang-Zhu; Kang, Han-Han; Sun, Xiu-Dong; Wang, Wei

    2015-01-01

    As one of the largest gene families, F-box domain proteins have been found to play important roles in abiotic stress responses via the ubiquitin pathway. TaFBA1 encodes a homologous F-box protein contained in E3 ubiquitin ligases. In our previous study, we found that the overexpression of TaFBA1 enhanced drought tolerance in transgenic plants. To investigate the mechanisms involved, in this study, we investigated the tolerance of the transgenic plants to oxidative stress. Methyl viologen was used to induce oxidative stress conditions. Real-time PCR and western blot analysis revealed that TaFBA1 expression was up-regulated by oxidative stress treatments. Under oxidative stress conditions, the transgenic tobacco plants showed a higher germination rate, higher root length and less growth inhibition than wild type (WT). The enhanced oxidative stress tolerance of the transgenic plants was also indicated by lower reactive oxygen species (ROS) accumulation, malondialdehyde (MDA) content and cell membrane damage under oxidative stress compared with WT. Higher activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD), were observed in the transgenic plants than those in WT, which may be related to the upregulated expression of some antioxidant genes via the overexpression of TaFBA1. In others, some stress responsive elements were found in the promoter region of TaFBA1, and TaFBA1 was located in the nucleus, cytoplasm and plasma membrane. These results suggest that TaFBA1 plays an important role in the oxidative stress tolerance of plants. This is important for understanding the functions of F-box proteins in plants' tolerance to multiple stress conditions.

  11. A comparative study of fatty acid profile and formation of biofilm in Geobacillus gargensis exposed to variable abiotic stress.

    Science.gov (United States)

    Al-Beloshei, Noor Essa; Al-Awadhi, Husain; Al-Khalaf, Rania A; Afzal, Mohammad

    2015-01-01

    Understanding bacterial fatty acid (FA) profile has a great taxonomic significance as well as clinical importance for diagnosis issues. Both the composition and nature of membrane FAs change under different nutritional, biotic and (or) abiotic stresses, and environmental stress. Bacteria produce both odd-carbon as well as branched-chain fatty acids (BCFAs). This study was designed to examine the effect of abiotic pressure, including salinity, temperature, pH, and oxinic stress on the growth, development, and FA profile in thermophilic Geobacillus gargensis. Under these stresses, 3 parametric ratios, 2-methyl fatty acids/3-methyl fatty acids (iso-/anteiso-FAs), BCFAs/straight-chain saturated fatty acids (SCSFA), and SCSFAs/straight-chain unsaturated fatty acids (SCUFA), in addition to total lipids affected by variable stresses were measured. Our results indicate that the ratio of total iso-/anteiso-FAs increased at the acidic pH range of 4.1-5.2 and decreased with increasing pH. The reverse was true for salt stress when iso-/anteiso-FAs ratio increased with salt concentration. The BCFAs/SCSFAs and SCSFAs/SCUFAs ratios increased at neutral and alkaline pH and high salt concentration, reduced incubation time, and comparatively high temperature (55-65 °C) of the growth medium. The bacterial total lipid percentage deceased with increasing salt concentration, incubation period, but it increased with temperature. The formation of extracellular polymeric substances was observed under all stress conditions and with the addition of sodium dodecyl sulfate (2 and 5 mmol/L) to the growth medium. The membrane phospholipid composition of the bacterium was analyzed by thin-layer chromatography.

  12. Stress test: identifying crowding stress-tolerant hybrids in processing sweet corn

    Science.gov (United States)

    Improvement in tolerance to intense competition at high plant populations (i.e. crowding stress) is a major genetic driver of corn yield gain the last half-century. Recent research found differences in crowding stress tolerance among a few modern processing sweet corn hybrids; however, a larger asse...

  13. Impact of biotic and abiotic stresses on the competitive ability of multiple herbicide resistant wild oat (Avena fatua.

    Directory of Open Access Journals (Sweden)

    Erik A Lehnhoff

    Full Text Available Ecological theory predicts that fitness costs of herbicide resistance should lead to the reduced relative abundance of resistant populations upon the cessation of herbicide use. This greenhouse research investigated the potential fitness costs of two multiple herbicide resistant (MHR wild oat (Avena fatua populations, an economically important weed that affects cereal and pulse crop production in the Northern Great Plains of North America. We compared the competitive ability of two MHR and two herbicide susceptible (HS A. fatua populations along a gradient of biotic and abiotic stresses The biotic stress was imposed by three levels of wheat (Triticum aestivum competition (0, 4, and 8 individuals pot(-1 and an abiotic stress by three nitrogen (N fertilization rates (0, 50 and 100 kg N ha(-1. Data were analyzed with linear mixed-effects models and results showed that the biomass of all A. fatua populations decreased with increasing T. aestivum competition at all N rates. Similarly, A. fatua relative growth rate (RGR decreased with increasing T. aestivum competition at the medium and high N rates but there was no response with 0 N. There were no differences between the levels of biomass or RGR of HS and MHR populations in response to T. aestivum competition. Overall, the results indicate that MHR does not confer growth-related fitness costs in these A. fatua populations, and that their relative abundance will not be diminished with respect to HS populations in the absence of herbicide treatment.

  14. Impact of biotic and abiotic stresses on the competitive ability of multiple herbicide resistant wild oat (Avena fatua).

    Science.gov (United States)

    Lehnhoff, Erik A; Keith, Barbara K; Dyer, William E; Menalled, Fabian D

    2013-01-01

    Ecological theory predicts that fitness costs of herbicide resistance should lead to the reduced relative abundance of resistant populations upon the cessation of herbicide use. This greenhouse research investigated the potential fitness costs of two multiple herbicide resistant (MHR) wild oat (Avena fatua) populations, an economically important weed that affects cereal and pulse crop production in the Northern Great Plains of North America. We compared the competitive ability of two MHR and two herbicide susceptible (HS) A. fatua populations along a gradient of biotic and abiotic stresses The biotic stress was imposed by three levels of wheat (Triticum aestivum) competition (0, 4, and 8 individuals pot(-1)) and an abiotic stress by three nitrogen (N) fertilization rates (0, 50 and 100 kg N ha(-1)). Data were analyzed with linear mixed-effects models and results showed that the biomass of all A. fatua populations decreased with increasing T. aestivum competition at all N rates. Similarly, A. fatua relative growth rate (RGR) decreased with increasing T. aestivum competition at the medium and high N rates but there was no response with 0 N. There were no differences between the levels of biomass or RGR of HS and MHR populations in response to T. aestivum competition. Overall, the results indicate that MHR does not confer growth-related fitness costs in these A. fatua populations, and that their relative abundance will not be diminished with respect to HS populations in the absence of herbicide treatment.

  15. Role of peroxidases in the compensation of cytosolic ascorbate peroxidase knockdown in rice plants under abiotic stress.

    Science.gov (United States)

    Bonifacio, Aurenivia; Martins, Marcio O; Ribeiro, Carolina W; Fontenele, Adilton V; Carvalho, Fabricio E L; Margis-Pinheiro, Márcia; Silveira, Joaquim A G

    2011-10-01

    Current studies, particularly in Arabidopsis, have demonstrated that mutants deficient in cytosolic ascorbate peroxidases (APXs) are susceptible to the oxidative damage induced by abiotic stress. In contrast, we demonstrate here that rice mutants double silenced for cytosolic APXs (APx1/2s) up-regulated other peroxidases, making the mutants able to cope with abiotic stress, such as salt, heat, high light and methyl viologen, similar to non-transformed (NT) plants. The APx1/2s mutants exhibited an altered redox homeostasis, as indicated by increased levels of H₂O₂ and ascorbate and glutathione redox states. Both mutant and NT plants exhibited similar photosynthesis (CO₂) assimilation and photochemical efficiency) under both normal and stress conditions. Overall, the antioxidative compensatory mechanism displayed by the mutants was associated with increased expression of OsGpx genes, which resulted in higher glutathione peroxidase (GPX) activity in the cytosolic and chloroplastic fractions. The transcript levels of OsCatA and OsCatB and the activities of catalase (CAT) and guaiacol peroxidase (GPOD; type III peroxidases) were also up-regulated. None of the six studied isoforms of OsApx were up-regulated under normal growth conditions. Therefore, the deficiency in cytosolic APXs was effectively compensated for by up-regulation of other peroxidases. We propose that signalling mechanisms triggered in rice mutants could be distinct from those proposed for Arabidopsis.

  16. Genome-Wide Identification and Expression Analyses of Aquaporin Gene Family during Development and Abiotic Stress in Banana.

    Science.gov (United States)

    Hu, Wei; Hou, Xiaowan; Huang, Chao; Yan, Yan; Tie, Weiwei; Ding, Zehong; Wei, Yunxie; Liu, Juhua; Miao, Hongxia; Lu, Zhiwei; Li, Meiying; Xu, Biyu; Jin, Zhiqiang

    2015-08-20

    Aquaporins (AQPs) function to selectively control the flow of water and other small molecules through biological membranes, playing crucial roles in various biological processes. However, little information is available on the AQP gene family in bananas. In this study, we identified 47 banana AQP genes based on the banana genome sequence. Evolutionary analysis of AQPs from banana, Arabidopsis, poplar, and rice indicated that banana AQPs (MaAQPs) were clustered into four subfamilies. Conserved motif analysis showed that all banana AQPs contained the typical AQP-like or major intrinsic protein (MIP) domain. Gene structure analysis suggested the majority of MaAQPs had two to four introns with a highly specific number and length for each subfamily. Expression analysis of MaAQP genes during fruit development and postharvest ripening showed that some MaAQP genes exhibited high expression levels during these stages, indicating the involvement of MaAQP genes in banana fruit development and ripening. Additionally, some MaAQP genes showed strong induction after stress treatment and therefore, may represent potential candidates for improving banana resistance to abiotic stress. Taken together, this study identified some excellent tissue-specific, fruit development- and ripening-dependent, and abiotic stress-responsive candidate MaAQP genes, which could lay a solid foundation for genetic improvement of banana cultivars.

  17. Genome-Wide Identification and Expression Analyses of Aquaporin Gene Family during Development and Abiotic Stress in Banana

    Directory of Open Access Journals (Sweden)

    Wei Hu

    2015-08-01

    Full Text Available Aquaporins (AQPs function to selectively control the flow of water and other small molecules through biological membranes, playing crucial roles in various biological processes. However, little information is available on the AQP gene family in bananas. In this study, we identified 47 banana AQP genes based on the banana genome sequence. Evolutionary analysis of AQPs from banana, Arabidopsis, poplar, and rice indicated that banana AQPs (MaAQPs were clustered into four subfamilies. Conserved motif analysis showed that all banana AQPs contained the typical AQP-like or major intrinsic protein (MIP domain. Gene structure analysis suggested the majority of MaAQPs had two to four introns with a highly specific number and length for each subfamily. Expression analysis of MaAQP genes during fruit development and postharvest ripening showed that some MaAQP genes exhibited high expression levels during these stages, indicating the involvement of MaAQP genes in banana fruit development and ripening. Additionally, some MaAQP genes showed strong induction after stress treatment and therefore, may represent potential candidates for improving banana resistance to abiotic stress. Taken together, this study identified some excellent tissue-specific, fruit development- and ripening-dependent, and abiotic stress-responsive candidate MaAQP genes, which could lay a solid foundation for genetic improvement of banana cultivars.

  18. Molecular characterization of Alr1105 a novel arsenate reductase of the diazotrophic cyanobacterium Anabaena sp. PCC7120 and decoding its role in abiotic stress management in Escherichia coli.

    Science.gov (United States)

    Pandey, Sarita; Shrivastava, Alok K; Rai, Rashmi; Rai, Lal Chand

    2013-11-01

    This paper constitutes the first report on the Alr1105 of Anabaena sp. PCC7120 which functions as arsenate reductase and phosphatase and offers tolerance against oxidative and other abiotic stresses in the alr1105 transformed Escherichia coli. The bonafide of 40.8 kDa recombinant GST+Alr1105 fusion protein was confirmed by immunoblotting. The purified Alr1105 protein (mw 14.8 kDa) possessed strong arsenate reductase (Km 16.0 ± 1.2 mM and Vmax 5.6 ± 0.31 μmol min⁻¹ mg protein⁻¹) and phosphatase activity (Km 27.38 ± 3.1 mM and Vmax 0.077 ± 0.005 μmol min⁻¹ mg protein⁻¹) at an optimum temperature 37 °C and 6.5 pH. Native Alr1105 was found as a monomeric protein in contrast to its homologous Synechocystis ArsC protein. Expression of Alr1105 enhanced the arsenic tolerance in the arsenate reductase mutant E. coli WC3110 (∆arsC) and rendered better growth than the wild type W3110 up to 40 mM As (V). Notwithstanding above, the recombinant E. coli strain when exposed to CdCl₂, ZnSO₄, NiCl₂, CoCl₂, CuCl₂, heat, UV-B and carbofuron showed increase in growth over the wild type and mutant E. coli transformed with the empty vector. Furthermore, an enhanced growth of the recombinant E. coli in the presence of oxidative stress producing chemicals (MV, PMS and H₂O₂), suggested its protective role against these stresses. Appreciable expression of alr1105 gene as measured by qRT-PCR at different time points under selected stresses reconfirmed its role in stress tolerance. Thus the Alr1105 of Anabaena sp. PCC7120 functions as an arsenate reductase and possess novel properties different from the arsenate reductases known so far.

  19. Genome-Wide Characterization and Expression Analysis of Major Intrinsic Proteins during Abiotic and Biotic Stresses in Sweet Orange (Citrus sinensis L. Osb..

    Directory of Open Access Journals (Sweden)

    Cristina de Paula Santos Martins

    Full Text Available The family of aquaporins (AQPs, or major intrinsic proteins (MIPs, includes integral membrane proteins that function as transmembrane channels for water and other small molecules of physiological significance. MIPs are classified into five subfamilies in higher plants, including plasma membrane (PIPs, tonoplast (TIPs, NOD26-like (NIPs, small basic (SIPs and unclassified X (XIPs intrinsic proteins. This study reports a genome-wide survey of MIP encoding genes in sweet orange (Citrus sinensis L. Osb., the most widely cultivated Citrus spp. A total of 34 different genes encoding C. sinensis MIPs (CsMIPs were identified and assigned into five subfamilies (CsPIPs, CsTIPs, CsNIPs, CsSIPs and CsXIPs based on sequence analysis and also on their phylogenetic relationships with clearly classified MIPs of Arabidopsis thaliana. Analysis of key amino acid residues allowed the assessment of the substrate specificity of each CsMIP. Gene structure analysis revealed that the CsMIPs possess an exon-intron organization that is highly conserved within each subfamily. CsMIP loci were precisely mapped on every sweet orange chromosome, indicating a wide distribution of the gene family in the sweet orange genome. Investigation of their expression patterns in different tissues and upon drought and salt stress treatments, as well as with 'Candidatus Liberibacter asiaticus' infection, revealed a tissue-specific and coordinated regulation of the different CsMIP isoforms, consistent with the organization of the stress-responsive cis-acting regulatory elements observed in their promoter regions. A special role in regulating the flow of water and nutrients is proposed for CsTIPs and CsXIPs during drought stress, and for most CsMIPs during salt stress and the development of HLB disease. These results provide a valuable reference for further exploration of the CsMIPs functions and applications to the genetic improvement of both abiotic and biotic stress tolerance in citrus.

  20. Genome-Wide Characterization and Expression Analysis of Major Intrinsic Proteins during Abiotic and Biotic Stresses in Sweet Orange (Citrus sinensis L. Osb.).

    Science.gov (United States)

    Martins, Cristina de Paula Santos; Pedrosa, Andresa Muniz; Du, Dongliang; Gonçalves, Luana Pereira; Yu, Qibin; Gmitter, Frederick G; Costa, Marcio Gilberto Cardoso

    2015-01-01

    The family of aquaporins (AQPs), or major intrinsic proteins (MIPs), includes integral membrane proteins that function as transmembrane channels for water and other small molecules of physiological significance. MIPs are classified into five subfamilies in higher plants, including plasma membrane (PIPs), tonoplast (TIPs), NOD26-like (NIPs), small basic (SIPs) and unclassified X (XIPs) intrinsic proteins. This study reports a genome-wide survey of MIP encoding genes in sweet orange (Citrus sinensis L. Osb.), the most widely cultivated Citrus spp. A total of 34 different genes encoding C. sinensis MIPs (CsMIPs) were identified and assigned into five subfamilies (CsPIPs, CsTIPs, CsNIPs, CsSIPs and CsXIPs) based on sequence analysis and also on their phylogenetic relationships with clearly classified MIPs of Arabidopsis thaliana. Analysis of key amino acid residues allowed the assessment of the substrate specificity of each CsMIP. Gene structure analysis revealed that the CsMIPs possess an exon-intron organization that is highly conserved within each subfamily. CsMIP loci were precisely mapped on every sweet orange chromosome, indicating a wide distribution of the gene family in the sweet orange genome. Investigation of their expression patterns in different tissues and upon drought and salt stress treatments, as well as with 'Candidatus Liberibacter asiaticus' infection, revealed a tissue-specific and coordinated regulation of the different CsMIP isoforms, consistent with the organization of the stress-responsive cis-acting regulatory elements observed in their promoter regions. A special role in regulating the flow of water and nutrients is proposed for CsTIPs and CsXIPs during drought stress, and for most CsMIPs during salt stress and the development of HLB disease. These results provide a valuable reference for further exploration of the CsMIPs functions and applications to the genetic improvement of both abiotic and biotic stress tolerance in citrus.

  1. Advances in Melatonin and Its Roles in Abiotic Stress Resistance in Plants%褪黑素与植物抗逆性研究进展

    Institute of Scientific and Technical Information of China (English)

    姜超强; 祖朝龙

    2015-01-01

    Evidence has confirmed that the presence of melatonin in plants is universal. Melatonin has importance roles in many aspects of plant growth and development. The most frequently mentioned functions of melatonin are related to abiotic stresses such as drought, salt stress, extreme temperature, and oxidative stresses. Nowadays, with understanding deepening of melatonin, studies about the effect of melatonin on abiotic stresses resistance in plants have made plentiful and substantial achievements. This review mainly focuses on the biosynthesis pathway of melatonin, exogenously applied melatonin affects stress tolerance and melatonin levels in plants under stress conditions, and also proposes the potential subjects of melatonin in plant. The findings are as follows, although it has been suggested that plant melatonin is synthesized via similar biosynthetic pathways to those in animals, the exact biosynthetic pathway and the specific sites remain unclear. Evidence indicates that exogenously applied melatonin can also improve abiotic stress resistance in plants. Environmental stress can enhance the level of endogenous melatonin in plants, and overexpression of the melatonin biosynthetic genes can also increase melatonin levels.%褪黑素广泛存在于植物体内,对植物生长和发育方面有着重要的作用。其中,最为人们关注的是褪黑素在植物抵御干旱、高盐、极端温度和氧化胁迫等不良影响中所发挥的重要功能。随着人们对褪黑素研究的深入,褪黑素在植物体中发挥的作用和功能也更加明确,国内外在褪黑素与植物抗逆性关系的研究也取得了丰硕的成果。主要从植物体中褪黑素的合成途径、褪黑素在植物抗性反应中的作用以及内源褪黑素含量与逆境等方面进行了综述,并提出今后的研究方向。可以归纳为:植物体内褪黑素的合成机制与动物体内相似,但是确切的生物合成途径

  2. Differential Regulation of Genes Coding for Organelle and Cytosolic ClpATPases under Biotic and Abiotic Stresses in Wheat

    Science.gov (United States)

    Muthusamy, Senthilkumar K.; Dalal, Monika; Chinnusamy, Viswanathan; Bansal, Kailash C.

    2016-01-01

    A sub-group of class I Caseinolytic proteases (Clps) function as molecular chaperone and confer thermotolerance to plants. We identified class I Clp family consisting of five ClpB/HSP100, two ClpC, and two ClpD genes from bread wheat. Phylogenetic analysis showed that these genes were highly conserved across grass genomes. Subcellular localization prediction revealed that TaClpC and TaClpD subgroup proteins and TaClpB1 proteins are potentially targeted to chloroplast, while TaClpB5 to mitochondria, and TaClpB2, TaClpB3, and TaClpB4 to cytoplasm. Spatio-temporal expression pattern analysis revealed that four TaClpB and TaClpD2 genes are expressed in majority of all tissues and developmental stages of wheat. Real-time RT-PCR analysis of expression levels of Clp genes in seven wheat genotypes under different abiotic stresses revealed that genes coding for the cytosolic Clps namely TaClpB2 and TaClpB3 were upregulated under heat, salt and oxidative stress but were downregulated by cold stress in most genotypes. In contrast, genes coding for the chloroplastic Clps TaClpC1, TaClpC2, and TaClpD1 genes were significantly upregulated by mainly by cold stress in most genotypes, while TaClpD2 gene was upregulated >2 fold by salt stress in DBW16. The TaClpB5 gene coding for mitochondrial Clp was upregulated in all genotypes under heat, salt and oxidative stresses. In addition, we found that biotic stresses also upregulated TaClpB4 and TaClpD1. Among biotic stresses, Tilletia caries induced TaClpB2, TaClpB3, TaClpC1, and TaClpD1. Differential expression pattern under different abiotic and biotic stresses and predicted differential cellular localization of Clps suggest their non-redundant organelle and stress-specific roles. Our results also suggest the potential role of Clps in cold, salt and biotic stress responses in addition to the previously established role in thermotolerance of wheat. PMID:27446158

  3. Gene expression and functional analyses in brassinosteroid-mediated stress tolerance.

    Science.gov (United States)

    Divi, Uday K; Rahman, Tawhidur; Krishna, Priti

    2016-01-01

    The plant hormone brassinosteroid (BR) plays essential roles in plant growth and development, while also controlling plant stress responses. This dual ability of BR is intriguing from a mechanistic point of view and as a viable solution for stabilizing crop yields under the changing climatic conditions. Here we report a time course analysis of BR responses under both stress and no-stress conditions, the results of which establish that BR incorporates many stress-related features even under no-stress conditions, which are then accompanied by a dynamic stress response under unfavourable conditions. Found within the BR transcriptome were distinct molecular signatures of two stress hormones, abscisic acid and jasmonic acid, which were correlated with enhanced endogenous levels of the two hormones in BR-treated seedlings. The marked presence of genes related to protein metabolism and modification, defence responses and calcium signalling highlights the significance of their associated mechanisms and roles in BR processes. Functional analysis of loss-of-function mutants of a subset of genes selected from the BR transcriptome identified abiotic stress-related roles for ACID PHOSPHATASE5 (ACP5), WRKY33, JACALIN-RELATED LECTIN1-3 (JAC-LEC1-3) and a BR-RESPONSIVE-RECEPTOR-LIKE KINASE (BRRLK). Overall, the results of this study provide a clear link between the molecular changes impacted by BR and its ability to confer broad-range stress tolerance, emphasize the importance of post-translational modification and protein turnover as BR regulatory mechanisms and demonstrate the BR transcriptome as a repertoire of new stress-related regulatory and structural genes.

  4. Microorganisms having enhanced tolerance to inhibitors and stress

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Steven D.; Yang, Shihui

    2014-07-29

    The present invention provides genetically modified strains of microorganisms that display enhanced tolerance to stress and/or inhibitors such as sodium acetate and vanillin. The enhanced tolerance can be achieved by increasing the expression of a protein of the Sm-like superfamily such as a bacterial Hfq protein and a fungal Sm or Lsm protein. Further, the present invention provides methods of producing alcohol from biomass materials by using the genetically modified microorganisms of the present invention.

  5. Genome-wide identification and expression profiling analysis of ZmPIN, ZmPILS, ZmLAX and ZmABCB auxin transporter gene families in maize (Zea mays L. under various abiotic stresses.

    Directory of Open Access Journals (Sweden)

    Runqing Yue

    Full Text Available The auxin influx carriers auxin resistant 1/like aux 1 (AUX/LAX, efflux carriers pin-formed (PIN (together with PIN-like proteins and efflux/conditional P-glycoprotein (ABCB are major protein families involved in auxin polar transport. However, how they function in responses to exogenous auxin and abiotic stresses in maize is largely unknown. In this work, the latest updated maize (Zea mays L. reference genome sequence was used to characterize and analyze the ZmLAX, ZmPIN, ZmPILS and ZmABCB family genes from maize. The results showed that five ZmLAXs, fifteen ZmPINs, nine ZmPILSs and thirty-five ZmABCBs were mapped on all ten maize chromosomes. Highly diversified gene structures, nonconservative transmembrane helices and tissue-specific expression patterns suggested the possibility of function diversification for these genes. Quantitative real-time polymerase chain reaction (qRT-PCR was used to analyze the expression patterns of ZmLAX, ZmPIN, ZmPILS and ZmABCB genes under exogenous auxin and different environmental stresses. The expression levels of most ZmPIN, ZmPILS, ZmLAX and ZmABCB genes were induced in shoots and were reduced in roots by various abiotic stresses (drought, salt and cold stresses. The opposite expression response patterns indicated the dynamic auxin transport between shoots and roots under abiotic stresses. Analysis of the expression patterns of ZmPIN, ZmPILS, ZmLAX and ZmABCB genes under drought, salt and cold treatment may help us to understand the possible roles of maize auxin transporter genes in responses and tolerance to environmental stresses.

  6. Genome-Wide Analysis of C2H2 Zinc-Finger Family Transcription Factors and Their Responses to Abiotic Stresses in Poplar (Populus trichocarpa.

    Directory of Open Access Journals (Sweden)

    Quangang Liu

    Full Text Available C2H2 zinc-finger (C2H2-ZF proteins are a large gene family in plants that participate in various aspects of normal plant growth and development, as well as in biotic and abiotic stress responses. To date, no overall analysis incorporating evolutionary history and expression profiling of the C2H2-ZF gene family in model tree species poplar (Populus trichocarpa has been reported.Here, we identified 109 full-length C2H2-ZF genes in P. trichocarpa, and classified them into four groups, based on phylogenetic analysis. The 109 C2H2-ZF genes were distributed unequally on 19 P. trichocarpa linkage groups (LGs, with 39 segmental duplication events, indicating that segmental duplication has been important in the expansion of the C2H2-ZF gene family. Promoter cis-element analysis indicated that most of the C2H2-ZF genes contain phytohormone or abiotic stress-related cis-elements. The expression patterns of C2H2-ZF genes, based on heatmap analysis, suggested that C2H2-ZF genes are involved in tissue and organ development, especially root and floral development. Expression analysis based on quantitative real-time reverse transcription polymerase chain reaction indicated that C2H2-ZF genes are significantly involved in drought, heat and salt response, possibly via different mechanisms.This study provides a thorough overview of the P. trichocarpa C2H2-ZF gene family and presents a new perspective on the evolution of this gene family. In particular, some C2H2-ZF genes may be involved in environmental stress tolerance regulation. PtrZFP2, 19 and 95 showed high expression levels in leaves and/or roots under environmental stresses. Additionally, this study provided a solid foundation for studying the biological roles of C2H2-ZF genes in Populus growth and development. These results form the basis for further investigation of the roles of these candidate genes and for future genetic engineering and gene functional studies in Populus.

  7. Over-expression of a novel JAZ family gene from Glycine soja, increases salt and alkali stress tolerance.

    Science.gov (United States)

    Zhu, Dan; Cai, Hua; Luo, Xiao; Bai, Xi; Deyholos, Michael K; Chen, Qin; Chen, Chao; Ji, Wei; Zhu, Yanming

    2012-09-21

    Salt and alkali stress are two of the main environmental factors limiting crop production. Recent discoveries show that the JAZ family encodes plant-specific genes involved in jasmonate signaling. However, there is only limited information about this gene family in abiotic stress response, and in wild soybean (Glycine soja), which is a species noted for its tolerance to alkali and salinity. Here, we isolated and characterized a novel JAZ family gene, GsJAZ2, from G. soja. Transcript abundance of GsJAZ2 increased following exposure to salt, alkali, cold and drought. Over-expression of GsJAZ2 in Arabidopsis resulted in enhanced plant tolerance to salt and alkali stress. The expression levels of some alkali stress response and stress-inducible marker genes were significantly higher in the GsJAZ2 overexpression lines as compared to wild-type plants. Subcellular localization studies using a GFP fusion protein showed that GsJAZ2 was localized to the nucleus. These results suggest that the newly isolated wild soybean GsJAZ2 is a positive regulator of plant salt and alkali stress tolerance.

  8. Suitable reference genes for accurate gene expression analysis in parsley (Petroselinum crispum for abiotic stresses and hormone stimuli

    Directory of Open Access Journals (Sweden)

    Meng-Yao Li

    2016-09-01

    Full Text Available Parsley is one of the most important vegetable in Apiaceae family and widely used in food industry, medicinal and cosmetic. The recent studies in parsley are mainly focus on chemical composition, further research involving the analysis of the gene functions and expressions will be required. qPCR is a powerful method for detecting very low quantities of target transcript levels and widely used for gene expression studies. To ensure the accuracy of results, a suitable reference gene is necessary for expression normalization. In this study, three software geNorm, NormFinder, and BestKeeper were used to evaluate the expression stabilities of eight candidate reference genes (GAPDH, ACTIN, eIF-4α, SAND, UBC, TIP41, EF-1α, and TUB under various conditions including abiotic stresses (heat, cold, salt, and drought and hormone stimuli treatments (GA, SA, MeJA, and ABA. The results showed that EF-1α and TUB were identified as the most stable genes for abiotic stresses, while EF-1α, GAPDH, and TUB were the top three choices for hormone stimuli treatments. Moreover, EF-1α and TUB were the most stable reference genes across all the tested samples, while UBC was the least stable one. The expression analysis of PcDREB1 and PcDREB2 further verified that the selected stable reference genes were suitable for gene expression normalization. This study provides a guideline for selection the suitable reference genes in gene expression in parsley.

  9. Validation of potential reference genes for qPCR in maize across abiotic stresses, hormone treatments, and tissue types.

    Directory of Open Access Journals (Sweden)

    Yueai Lin

    Full Text Available The reverse transcription quantitative polymerase chain reaction (RT-qPCR is a powerful and widely used technique for the measurement of gene expression. Reference genes, which serve as endogenous controls ensure that the results are accurate and reproducible, are vital for data normalization. To bolster the literature on reference gene selection in maize, ten candidate reference genes, including eight traditionally used internal control genes and two potential candidate genes from our microarray datasets, were evaluated for expression level in maize across abiotic stresses (cold, heat, salinity, and PEG, phytohormone treatments (abscisic acid, salicylic acid, jasmonic acid, ethylene, and gibberellins, and different tissue types. Three analytical software packages, geNorm, NormFinder, and Bestkeeper, were used to assess the stability of reference gene expression. The results revealed that elongation factor 1 alpha (EF1α, tubulin beta (β-TUB, cyclophilin (CYP, and eukaryotic initiation factor 4A (EIF4A were the most reliable reference genes for overall gene expression normalization in maize, while GRP (Glycine-rich RNA-binding protein, GLU1(beta-glucosidase, and UBQ9 (ubiquitin 9 were the least stable and most unsuitable genes. In addition, the suitability of EF1α, β-TUB, and their combination as reference genes was confirmed by validating the expression of WRKY50 in various samples. The current study indicates the appropriate reference genes for the urgent requirement of gene expression normalization in maize across certain abiotic stresses, hormones, and tissue types.

  10. Antioxidant response resides in the shoot in reciprocal grafts of drought-tolerant and drought-sensitive cultivars in tomato under water stress.

    Science.gov (United States)

    Sánchez-Rodríguez, Eva; Rubio-Wilhelmi, María del Mar; Blasco, Begoña; Leyva, Rocío; Romero, Luis; Ruiz, Juan Manuel

    2012-06-01

    Recently grafted plants have been used to induce resistance to different abiotic stresses. In our work, grafted plants of tomato cultivars differing in water stress tolerance (Zarina and Josefina) were grown under moderate stress, to test the roles of roots and shoots in production of foliar biomass and antioxidant response. Stress indicators and activities of selected enzymes related to antioxidant response were determined. Our results showed that when shoots are of the drought tolerant genotype Zarina, the changes in antioxidant enzyme activities were large and consistent. However, when shoots are of the drought-sensitive genotype Josefina, the antioxidant enzyme activities were more limited and the oxidative stress was evident. These results reflect that the technique of grafting using Zarina as scion can be useful and effective for improving the antioxidant response in tomato under water stress.

  11. Arabidopsis thaliana glyoxalase 2-1 is required during abiotic stress but is not essential under normal plant growth.

    Directory of Open Access Journals (Sweden)

    Sriram Devanathan

    Full Text Available The glyoxalase pathway, which consists of the two enzymes, GLYOXALASE 1 (GLX 1 (E.C.: 4.4.1.5 and 2 (E.C.3.1.2.6, has a vital role in chemical detoxification. In Arabidopsis thaliana there are at least four different isoforms of glyoxalase 2, two of which, GLX2-1 and GLX2-4 have not been characterized in detail. Here, the functional role of Arabidopsis thaliana GLX2-1 is investigated. Glx2-1 loss-of-function mutants and plants that constitutively over-express GLX2-1 resemble wild-type plants under normal growth conditions. Insilico analysis of publicly available microarray datasets with ATTEDII, Mapman and Genevestigator indicate potential role(s in stress response and acclimation. Results presented here demonstrate that GLX2-1 gene expression is up-regulated in wild type Arabidopsis thaliana by salt and anoxia stress, and by excess L-Threonine. Additionally, a mutation in GLX2-1 inhibits growth and survival during abiotic stresses. Metabolic profiling studies show alterations in the levels of sugars and amino acids during threonine stress in the plants. Elevated levels of polyamines, which are known stress markers, are also observed. Overall our results suggest that Arabidopsis thaliana GLX2-1 is not essential during normal plant life, but is required during specific stress conditions.

  12. Impacts of priming with silicon on the growth and tolerance of maize plants to alkaline stress

    Directory of Open Access Journals (Sweden)

    ِArafat eAbdel Latef

    2016-03-01

    Full Text Available Silicon (Si has been known to augment plant defense against biotic and abiotic pressures. Maize (Zea maize L. is classified as a Si accumulator and is relatively susceptible to alkaline stress. In this work, grains of maize were grown in pots and exposed to various concentrations of Na2CO3 (0, 25, 50 and 75 mM with or without 1.5 mM Si in the form of sodium metasilicate Na2O3Si.5H2O for 25 days. Alkaline-stressed plants showed a decrease in growth parameters, leaf relative water content (LRWC, and the contents of photosynthetic pigments, soluble sugars, total phenols and potassium ion (K+, as well as potassium/sodium ion (K+/Na+ ratio. By contrast, alkaline stress increased the contents of soluble proteins, total free amino acids, proline, Na+ and malondialdehyde (MDA, as well as the activities of superoxide dismutase (SOD, catalase (CAT and peroxidase (POD in stressed plants. On the other hand, application of Si by grain priming improved growth of stressed plants, which was accompanied by the enhancement in LRWC, levels of photosynthetic pigments, soluble sugars, soluble proteins, total free amino acids, K+ and activities of SOD, CAT and POD enzymes. Furthermore, Si supplement resulted in a decrease in the contents of proline, MDA and Na+, which together with enhanced K+ level led to a favorable adjustment of K+/Na+ ratio, in stressed plants relative to plants treated with alkaline stress alone. Taken together, these results indicate that Si plays a pivotal role in alleviating the negative effects of alkaline stress on the maize growth by improving water status, enhancing photosynthetic pigments, accumulating osmoprotectants rather than proline, activating the antioxidant machinery, and maintaining the balance of K+/Na+. Thus, our findings demonstrate that seed priming with Si is an efficient strategy that can be used to boost tolerance of maize plants to alkaline stress.

  13. Increased fitness of rice plants to abiotic stress via habitat adapted symbiosis: A strategy for mitigating impacts of climate change

    Science.gov (United States)

    Redman, R.S.; Kim, Y.-O.; Woodward, C.J.D.A.; Greer, C.; Espino, L.; Doty, S.L.; Rodriguez, R.J.

    2011-01-01

    Climate change and catastrophic events have contributed to rice shortages in several regions due to decreased water availability and soil salinization. Although not adapted to salt or drought stress, two commercial rice varieties achieved tolerance to these stresses by colonizing them with Class 2 fungal endophytes isolated from plants growing across moisture and salinity gradients. Plant growth and development, water usage, ROS sensitivity and osmolytes were measured with and without stress under controlled conditions. The endophytes conferred salt, drought and cold tolerance to growth chamber and greenhouse grown plants. Endophytes reduced water consumption by 20–30% and increased growth rate, reproductive yield, and biomass of greenhouse grown plants. In the absence of stress, there was no apparent cost of the endophytes to plants, however, endophyte colonization decreased from 100% at planting to 65% compared to greenhouse plants grown under continual stress (maintained 100% colonization). These findings indicate that rice plants can exhibit enhanced stress tolerance via symbiosis with Class 2 endophytes, and suggest that symbiotic technology may be useful in mitigating impacts of climate change on other crops and expanding agricultural production onto marginal lands.

  14. Increased fitness of rice plants to abiotic stress via habitat adapted symbiosis: a strategy for mitigating impacts of climate change.

    Science.gov (United States)

    Redman, Regina S; Kim, Yong Ok; Woodward, Claire J D A; Greer, Chris; Espino, Luis; Doty, Sharon L; Rodriguez, Rusty J

    2011-01-01

    Climate change and catastrophic events have contributed to rice shortages in several regions due to decreased water availability and soil salinization. Although not adapted to salt or drought stress, two commercial rice varieties achieved tolerance to these stresses by colonizing them with Class 2 fungal endophytes isolated from plants growing across moisture and salinity gradients.Plant growth and development, water usage, ROS sensitivity and osmolytes were measured with and without stress under controlled conditions.The endophytes conferred salt, drought and cold tolerance to growth chamber and greenhouse grown plants. Endophytes reduced water consumption by 20-30% and increased growth rate, reproductive yield, and biomass of greenhouse grown plants. In the absence of stress, there was no apparent cost of the endophytes to plants, however, endophyte colonization decreased from 100% at planting to 65% compared to greenhouse plants grown under continual stress (maintained 100% colonization).These findings indicate that rice plants can exhibit enhanced stress tolerance via symbiosis with Class 2 endophytes, and suggest that symbiotic technology may be useful in mitigating impacts of climate change on other crops and expanding agricultural production onto marginal lands.

  15. Increased fitness of rice plants to abiotic stress via habitat adapted symbiosis: a strategy for mitigating impacts of climate change.

    Directory of Open Access Journals (Sweden)

    Regina S Redman

    Full Text Available Climate change and catastrophic events have contributed to rice shortages in several regions due to decreased water availability and soil salinization. Although not adapted to salt or drought stress, two commercial rice varieties achieved tolerance to these stresses by colonizing them with Class 2 fungal endophytes isolated from plants growing across moisture and salinity gradients.Plant growth and development, water usage, ROS sensitivity and osmolytes were measured with and without stress under controlled conditions.The endophytes conferred salt, drought and cold tolerance to growth chamber and greenhouse grown plants. Endophytes reduced water consumption by 20-30% and increased growth rate, reproductive yield, and biomass of greenhouse grown plants. In the absence of stress, there was no apparent cost of the endophytes to plants, however, endophyte colonization decreased from 100% at planting to 65% compared to greenhouse plants grown under continual stress (maintained 100% colonization.These findings indicate that rice plants can exhibit enhanced stress tolerance via symbiosis with Class 2 endophytes, and suggest that symbiotic technology may be useful in mitigating impacts of climate change on other crops and expanding agricultural production onto marginal lands.

  16. Identification of stress-induced genes from the drought-tolerant plant Prosopis juliflora (Swartz) DC. through analysis of expressed sequence tags.

    Science.gov (United States)

    George, Suja; Venkataraman, Gayatri; Parida, Ajay

    2007-05-01

    Abiotic stresses such as cold, salinity, drought, wounding, and heavy metal contamination adversely affect crop productivity throughout the world. Prosopis juliflora is a phreatophyte that can tolerate severe adverse environmental conditions such as drought, salinity, and heavy metal contamination. As a first step towards the characterization of genes that contribute to combating abiotic stress, construction and analysis of a cDNA library of P. juliflora genes is reported here. Random expressed sequence tag (EST) sequencing of 1750 clones produced 1467 high-quality reads. These clones were classified into functional categories, and BLAST comparisons revealed that 114 clones were homologous to genes implicated in stress response(s) and included heat shock proteins, metallothioneins, lipid transfer proteins, and late embryogenesis abundant proteins. Of the ESTs analyzed, 26% showed homology to previously uncharacterized genes in the databases. Fifty-two clones from this category were selected for reverse Northern analysis: 21 were shown to be upregulated and 16 downregulated. The results obtained by reverse Northern analysis were confirmed by Northern analysis. Clustering of the 1467 ESTs produced a total of 295 contigs encompassing 790 ESTs, resulting in a 54.2% redundancy. Two of the abundant genes coding for a nonspecific lipid transfer protein and late embryogenesis abundant protein were sequenced completely. Northern analysis (after polyethylene glycol stress) of the 2 genes was carried out. The implications of the analyzed genes in abiotic stress tolerance are also discussed.

  17. Housekeeping gene selection for real-time RT-PCR normalization in potato during biotic and abiotic stress.

    Science.gov (United States)

    Nicot, Nathalie; Hausman, Jean-François; Hoffmann, Lucien; Evers, Danièle

    2005-11-01

    Plant stress studies are more and more based on gene expression. The analysis of gene expression requires sensitive, precise, and reproducible measurements for specific mRNA sequences. Real-time RT-PCR is at present the most sensitive method for the detection of low abundance mRNA. To avoid bias, real-time RT-PCR is referred to one or several internal control genes, which should not fluctuate during treatments. Here, the non-regulation of seven housekeeping genes (beta-tubulin, cyclophilin, actin, elongation factor 1-alpha (ef1alpha), 18S rRNA, adenine phosphoribosyl transferase (aprt), and cytoplasmic ribosomal protein L2) during biotic (late blight) and abiotic stresses (cold and salt stress) was tested on potato plants using geNorm software. Results from the three experimental conditions indicated that ef1alpha was the most stable among the seven tested. The expression of the other housekeeping genes tested varied upon stress. In parallel, a study of the variability of expression of hsp20.2, shown to be implicated in late blight stress, was realized. The relative quantification of the hsp20.2 gene varied according to the internal control and the number of internal controls used, thus highlighting the importance of the choice of internal controls in such experiments.

  18. Identification and expression of C2H2 transcription factor genes in Carica papaya under abiotic and biotic stresses.

    Science.gov (United States)

    Jiang, Ling; Pan, Lin-jie

    2012-06-01

    C2H2 proteins belong to a group of transcription factors (TFs) existing as a superfamily that plays important roles in defense responses and various other physiological processes in plants. The present study aimed to screen for and identify C2H2 proteins associated with defense responses to abiotic and biotic stresses in Carica papaya L. Data were collected for 47,483 papaya-expressed sequence tags (ESTs). The full-length cDNA nucleotide sequences of 87 C2H2 proteins were predicated by BioEdit. All 91 C2H2 proteins were aligned, and a phylogenetic tree was constructed using DNAman. The expression levels of 42 C2H2 were analyzed under conditions of salt stress by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Methyl jasmonate treatment rapidly upregulated ZF(23.4) and ZF(30,912.1) by 18.6- and 21.7-fold, respectively. ZF(1.3), ZF(138.44), ZF(94.49), ZF(29.160), and ZF(20.206) were found to be downregulated after low temperature treatment at very significant levels (p papaya ringspot virus pathogen. ZF(30,912.1) was subcellularly localized in the nucleus by a transgenic fusion of pBS-ZF(30,912.1)-GFP into the protoplast of papaya. The results of the present study showed that ZF(30,912.1) could be an important TF that mediates responses to abiotic and biotic stresses in papaya.

  19. Evaluation of candidate reference genes for normalization of quantitative RT-PCR in soybean tissues under various abiotic stress conditions.

    Directory of Open Access Journals (Sweden)

    Dung Tien Le

    Full Text Available Quantitative RT-PCR can be a very sensitive and powerful technique for measuring differential gene expression. Changes in gene expression induced by abiotic stresses are complex and multifaceted, which make determining stably expressed genes for data normalization difficult. To identify the most suitable reference genes for abiotic stress studies in soybean, 13 candidate genes collected from literature were evaluated for stability of expression under dehydration, high salinity, cold and ABA (abscisic acid treatments using delta CT and geNorm approaches. Validation of reference genes indicated that the best reference genes are tissue- and stress-dependent. With respect to dehydration treatment, the Fbox/ABC, Fbox/60s gene pairs were found to have the highest expression stability in the root and shoot tissues of soybean seedlings, respectively. Fbox and 60s genes are the most suitable reference genes across dehydrated root and shoot tissues. Under salt stress the ELF1b/IDE and Fbox/ELF1b are the most stably expressed gene pairs in roots and shoots, respectively, while 60s/Fbox is the best gene pair in both tissues. For studying cold stress in roots or shoots, IDE/60s and Fbox/Act27 are good reference gene pairs, respectively. With regard to gene expression analysis under ABA treatment in either roots, shoots or across these tissues, 60s/ELF1b, ELF1b/Fbox and 60s/ELF1b are the most suitable reference genes, respectively. The expression of ELF1b/60s, 60s/Fbox and 60s/Fbox genes was most stable in roots, shoots and both tissues, respectively, under various stresses studied. Among the genes tested, 60s was found to be the best reference gene in different tissues and under various stress conditions. The highly ranked reference genes identified from this study were proved to be capable of detecting subtle differences in expression rates that otherwise would be missed if a less stable reference gene was used.

  20. Melatonin induces the transcripts of CBF/DREB1s and their involvement in both abiotic and biotic stresses in Arabidopsis.

    Science.gov (United States)

    Shi, Haitao; Qian, Yongqiang; Tan, Dun-Xian; Reiter, Russel J; He, Chaozu

    2015-10-01

    Melatonin (N-acetyl-5-methoxytryptamine) is a naturally occurring small molecule that acts as an important secondary messenger in plant stress responses. However, the mechanism underlying the melatonin-mediated signaling pathway in plant stress responses has not been established. C-repeat-binding factors (CBFs)/Drought response element Binding 1 factors (DREB1s) encode transcription factors that play important roles in plant stress responses. This study has determined that endogenous melatonin and transcripts level of CBFs (AtCBF1, AtCBF2, and AtCBF3) in Arabidopsis leaves were significantly induced by salt, drought, and cold stresses and by pathogen Pseudomonas syringe pv. tomato (Pst) DC3000 infection. Moreover, both exogenous melatonin treatment and overexpression of CBFs conferred enhanced resistance to both abiotic and biotic stresses in Arabidopsis. Notably, AtCBFs and exogenous melatonin treatment positively regulated the mRNA expression of several stress-responsive genes (COR15A, RD22, and KIN1) and accumulation of soluble sugars content such as sucrose in Arabidopsis under control and stress conditions. Additionally, exogenous sucrose also conferred improved resistance to both abiotic and biotic stresses in Arabidopsis. Taken together, this study indicates that AtCBFs confer enhanced resistance to both abiotic and biotic stresses, and AtCBF-mediated signaling pathway and sugar accumulation may be involved in melatonin-mediated stress response in Arabidopsis, at least partially.

  1. Over-expression of a novel JAZ family gene from Glycine soja, increases salt and alkali stress tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Dan; Cai, Hua; Luo, Xiao; Bai, Xi [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Deyholos, Michael K. [Department of Biological Sciences, University of Alberta, Edmonton, Canada T6G 2E9 (Canada); Chen, Qin [Lethbridge Research Centre, Agriculture and Agri-Food Canada, 5403-1 Ave., South P.O. Box 3000, Lethbridge, AB, Canada T1J 4B1 (Canada); Chen, Chao; Ji, Wei [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China); Zhu, Yanming, E-mail: ymzhu@neau.edu.cn [Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030 (China)

    2012-09-21

    Highlights: Black-Right-Pointing-Pointer We isolated and characterized a novel JAZ family gene, GsJAZ2, from Glycine soja. Black-Right-Pointing-Pointer Overexpression of GsJAZ2 enhanced plant tolerance to salt and alkali stress. Black-Right-Pointing-Pointer The transcriptions of stress marker genes were higher in GsJAZ2 overexpression lines. Black-Right-Pointing-Pointer GsJAZ2 was localized to nucleus. -- Abstract: Salt and alkali stress are two of the main environmental factors limiting crop production. Recent discoveries show that the JAZ family encodes plant-specific genes involved in jasmonate signaling. However, there is only limited information about this gene family in abiotic stress response, and in wild soybean (Glycine soja), which is a species noted for its tolerance to alkali and salinity. Here, we isolated and characterized a novel JAZ family gene, GsJAZ2, from G. soja. Transcript abundance of GsJAZ2 increased following exposure to salt, alkali, cold and drought. Over-expression of GsJAZ2 in Arabidopsis resulted in enhanced plant tolerance to salt and alkali stress. The expression levels of some alkali stress response and stress-inducible marker genes were significantly higher in the GsJAZ2 overexpression lines as compared to wild-type plants. Subcellular localization studies using a GFP fusion protein showed that GsJAZ2 was localized to the nucleus. These results suggest that the newly isolated wild soybean GsJAZ2 is a positive regulator of plant salt and alkali stress tolerance.

  2. Cloning and characterization of HbMT2a, a metallothionein gene from Hevea brasiliensis Muell. Arg differently responds to abiotic stress and heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yan; Chen, Yue Yi; Yang, Shu Guang; Tian, Wei Min, E-mail: wmtian9110@126.com

    2015-05-22

    Metallothioneins (MTs) are of low molecular mass, cysteine-rich proteins. They play an important role in the detoxification of heavy metals and homeostasis of intracellular metal ions, and protecting against intracellular oxidative damages. In this study a full-length cDNA of type 2 plant metallothioneins, HbMT2a, was isolated from 25 mM Polyethyleneglycol (PEG) stressed leaves of Hevea brasiliensis by RACE. The HbMT2a was 372 bp in length and had a 237 bp open reading frame (ORF) encoding for a protein of 78 amino acid residues with molecular mass of 7.772 kDa. The expression of HbMT2a in the detached leaves of rubber tree clone RY7-33-97 was up-regulated by Me-JA, ABA, PEG, H{sub 2}O{sub 2}, Cu{sup 2+} and Zn{sup 2+}, but down-regulated by water. The role of HbMT2a protein in protecting against metal toxicity was demonstrated in vitro. PET-28a-HbMT2-beared Escherichia coli. Differential expression of HbMT2a upon treatment with 10 °C was observed in the detached leaves of rubber tree clone 93-114 which is cold-resistant and Reken501 which is cold-sensitive. The expression patterns of HbMT2a in the two rubber tree clones may be ascribed to a change in the level of endogenous H{sub 2}O{sub 2}. - Highlights: • Cloning an HbMT2a gene from rubber tree. • Analyzing expression patterns of HbMT2a upon abiotic stress and heavy metal stress. • Finding different expression patterns of HbMT2a among two Hevea germplasm. • The expressed protein of HbMT2a enhances copper and zinc tolerance in Escherichia coli.

  3. Screening of tropical maize for salt stress tolerance

    Directory of Open Access Journals (Sweden)

    Carlos Daniel Giaveno

    2007-01-01

    Full Text Available Since salinity is a common stress factor in agricultural areas, the objective of this study was to evaluate thefeasibility of morphological and physiological traits as selection criteria of maize genotypes under salt stress. The experimentswere carried out in the stages of germination and early seedling growth. Root and shoot weight, leaf area, root and leaf waterpotential, photochemical efficiency and growth rate were measured during salt stress and stress recovery. Our resultsindicated the presence of genetic variability for germination, but no association between germination and early seedlinggrowth under salt stress. Traits associated with seedling vigor, such as seedling weight and growth rate, and photochemicalefficiency under stress conditions can be used as selection criteria for salt-tolerant maize in breeding programs.

  4. Evaluation of arbuscular mycorrhizal fungi capacity to alleviate abiotic stress of olive (Olea europaea L.) plants at different transplant conditions.

    Science.gov (United States)

    Bompadre, María Josefina; Pérgola, Mariana; Fernández Bidondo, Laura; Colombo, Roxana Paula; Silvani, Vanesa Analía; Pardo, Alejandro Guillermo; Ocampo, Juan Antonio; Godeas, Alicia Margarita

    2014-01-01

    The capacity of roots to sense soil physicochemical parameters plays an essential role in maintaining plant nutritional and developmental functions under abiotic stress. These conditions generate reactive oxygen species (ROS) in plant tissues causing oxidation of proteins and lipids among others. Some plants have developed adaptive mechanisms to counteract such adverse conditions such as symbiotic association with arbuscular mycorrhizal fungi (AMF). AMF enhance plant growth and improve transplant survival by protecting host plants against environmental stresses. The aim of this study was to evaluate the alleviation of transplanting stress by two strains of Rhizophagus irregularis (GC2 and GA5) in olive. Our results show that olive plants have an additional energetic expense in growth due to an adaptative response to the growing stage and to the mycorrhizal colonization at the first transplant. However, at the second transplant the coinoculation improves olive plant growth and protects against oxidative stress followed by the GA5-inoculation. In conclusion, a combination of two AMF strains at the beginning of olive propagation produces vigorous plants successfully protected in field cultivation even with an additional cost at the beginning of growth.

  5. Evaluation of Arbuscular Mycorrhizal Fungi Capacity to Alleviate Abiotic Stress of Olive (Olea europaea L. Plants at Different Transplant Conditions

    Directory of Open Access Journals (Sweden)

    María Josefina Bompadre

    2014-01-01

    Full Text Available The capacity of roots to sense soil physicochemical parameters plays an essential role in maintaining plant nutritional and developmental functions under abiotic stress. These conditions generate reactive oxygen species (ROS in plant tissues causing oxidation of proteins and lipids among others. Some plants have developed adaptive mechanisms to counteract such adverse conditions such as symbiotic association with arbuscular mycorrhizal fungi (AMF. AMF enhance plant growth and improve transplant survival by protecting host plants against environmental stresses. The aim of this study was to evaluate the alleviation of transplanting stress by two strains of Rhizophagus irregularis (GC2 and GA5 in olive. Our results show that olive plants have an additional energetic expense in growth due to an adaptative response to the growing stage and to the mycorrhizal colonization at the first transplant. However, at the second transplant the coinoculation improves olive plant growth and protects against oxidative stress followed by the GA5-inoculation. In conclusion, a combination of two AMF strains at the beginning of olive propagation produces vigorous plants successfully protected in field cultivation even with an additional cost at the beginning of growth.

  6. Evaluation of Arbuscular Mycorrhizal Fungi Capacity to Alleviate Abiotic Stress of Olive (Olea europaea L.) Plants at Different Transplant Conditions

    Science.gov (United States)

    Bompadre, María Josefina; Pérgola, Mariana; Fernández Bidondo, Laura; Colombo, Roxana Paula; Silvani, Vanesa Analía; Pardo, Alejandro Guillermo; Ocampo, Juan Antonio; Godeas, Alicia Margarita

    2014-01-01

    The capacity of roots to sense soil physicochemical parameters plays an essential role in maintaining plant nutritional and developmental functions under abiotic stress. These conditions generate reactive oxygen species (ROS) in plant tissues causing oxidation of proteins and lipids among others. Some plants have developed adaptive mechanisms to counteract such adverse conditions such as symbiotic association with arbuscular mycorrhizal fungi (AMF). AMF enhance plant growth and improve transplant survival by protecting host plants against environmental stresses. The aim of this study was to evaluate the alleviation of transplanting stress by two strains of Rhizophagus irregularis (GC2 and GA5) in olive. Our results show that olive plants have an additional energetic expense in growth due to an adaptative response to the growing stage and to the mycorrhizal colonization at the first transplant. However, at the second transplant the coinoculation improves olive plant growth and protects against oxidative stress followed by the GA5-inoculation. In conclusion, a combination of two AMF strains at the beginning of olive propagation produces vigorous plants successfully protected in field cultivation even with an additional cost at the beginning of growth. PMID:24688382

  7. The transcriptional network of WRKY53 in cereals links oxidative responses to biotic and abiotic stress inputs.

    Science.gov (United States)

    Van Eck, Leon; Davidson, Rebecca M; Wu, Shuchi; Zhao, Bingyu Y; Botha, Anna-Maria; Leach, Jan E; Lapitan, Nora L V

    2014-06-01

    The transcription factor WRKY53 is expressed during biotic and abiotic stress responses in cereals, but little is currently known about its regulation, structure and downstream targets. We sequenced the wheat ortholog TaWRKY53 and its promoter region, which revealed extensive similarity in gene architecture and cis-acting regulatory elements to the rice ortholog OsWRKY53, including the presence of stress-responsive abscisic acid-responsive elements (ABRE) motifs and GCC-boxes. Four proteins interacted with the WRKY53 promoter in yeast one-hybrid assays, suggesting that this gene can receive inputs from diverse stress-related pathways such as calcium signalling and senescence, and environmental cues such as drought and ultraviolet radiation. The Ser/Thr receptor kinase ORK10/LRK10 and the apoplastic peroxidase POC1 are two downstream targets for regulation by the WRKY53 transcription factor, predicted based on the presence of W-box motifs in their promoters and coregulation with WRKY53, and verified by electrophoretic mobility shift assay (EMSA). Both ORK10/LRK10 and POC1 are upregulated during cereal responses to pathogens and aphids and important components of the oxidative burst during the hypersensitive response. Taken with our yeast two-hybrid assay which identified a strong protein-protein interaction between microsomal glutathione S-transferase 3 and WRKY53, this implies that the WRKY53 transcriptional network regulates oxidative responses to a wide array of stresses.

  8. Reference Gene Validation for Quantitative PCR Under Various Biotic and Abiotic Stress Conditions in Toxoptera citricida (Hemiptera, Aphidiae).

    Science.gov (United States)

    Shang, Feng; Wei, Dan-Dan; Jiang, Xuan-Zhao; Wei, Dong; Shen, Guang-Mao; Feng, Ying-Cai; Li, Ting; Wang, Jin-Jun

    2015-08-01

    The regulation of mRNA expression level is critical for gene expression studies. Currently, quantitative reverse transcription polymerase chain reaction (qRT-PCR) is commonly used to investigate mRNA expression level of genes under various experimental conditions. An important factor that determines the optimal quantification of qRT-PCR data is the choice of the reference gene for normalization. To advance gene expression studies in Toxoptera citricida (Kirkaldy), an important citrus pest and a main vector of the Citrus tristeza virus, we used five tools (GeNorm, NormFinder, BestKeeper, ΔCt methods, and RefFinder) to evaluate seven candidate reference genes (elongation factor-1 alpha [EF1α], beta tubulin [β-TUB], 18S ribosomal RNA [18S], RNA polymerase II large subunit (RNAP II), beta actin (β-ACT), alpha tubulin, and glyceraldhyde-3-phosphate dehydrogenase) under different biotic (developmental stages and wing dimorphism) and abiotic stress (thermal, starvation, and UV irradiation) conditions. The results showed that EF1α and 18S were the most stable genes under various biotic states, β-ACT and β-TUB during thermal stress, EF1α and RNAP II under starvation stress, and RNAP II, β-ACT, and EF1α under UV irradiation stress conditions. This study provides useful resources for the transcriptional profiling of genes in T. citricida and closely related aphid species.

  9. Selected Abiotic and Biotic Environmental Stress Factors Affecting Two Economically Important Sugarcane Stalk Boring Pests in the United States

    Directory of Open Access Journals (Sweden)

    Allan T. Showler

    2016-02-01

    Full Text Available Sugarcane, Saccharum spp., in the United States is attacked by a number of different arthropod pests. The most serious among those pests are two stalk boring moths in the Family Crambidae: the sugarcane borer, Diatraea saccharalis (F., and the Mexican rice borer, Eoreuma loftini (Dyar. The two species are affected by abiotic and biotic environmental stress factors. Water deficit and excessive soil nitrogen alter physical and physiochemical aspects of the sugarcane plant that make the crop increasingly vulnerable to E. loftini. Weed growth can be competitive with sugarcane but it also supports enhanced abundances and diversity of natural enemies that can suppress infestations of D. saccharalis. In an instance where the stalk borer is considered a stress factor, proximity of vulnerable crops to sugarcane can influence levels of E. loftini infestation of sugarcane. The adverse effects of each stress factor, in terms of stalk borer attack, can be reduced by adopting appropriate cultural practices, such as adequate irrigation, judicious use of nitrogen fertilizer, using noncompetitive weed growth, and not planting vulnerable crops near sugarcane fields. Understanding the relationships between stress factors and crop pests can provide valuable insights for plant breeders and tools for incorporation into integrated pest management strategies.

  10. Overexpression of Rice Sphingosine-1-Phoshpate Lyase Gene OsSPL1 in Transgenic Tobacco Reduces Salt and Oxidative Stress Tolerance

    Institute of Scientific and Technical Information of China (English)

    Huijuan Zhang; Jing Zhai; Jibo Mo; Dayong Li; Fengming Song

    2012-01-01

    Sphingolipids,including sphingosine-1-phosphate (S1P),have been shown to function as signaling mediators to regulate diverse aspects of plant growth,development,and stress response.In this study,we performed functional analysis of a rice (Oryza sativa) S1P lyase gene OsSPL1 in transgenic tobacco plants and explored its possible involvement in abiotic stress response.Overexpression of OsSPL1 in transgenic tobacco resulted in enhanced sensitivity to exogenous abscisic acid (ABA),and decreased tolerance to salt and oxidative stress,when compared with the wild type.Furthermore,the expression levels of some selected stress-related genes in OsSPL1-overexpressing plants were reduced after application of salt or oxidative stress,indicating that the altered responsiveness of stress-related genes may be responsible for the reduced tolerance in OsSPL1-overexpressing tobacco plants under salt and oxidative stress.Our results suggest that rice OsSPL1 plays an important role in abiotic stress responses.

  11. Metabolomic approach for improving ethanol stress tolerance in Saccharomyces cerevisiae.

    Science.gov (United States)

    Ohta, Erika; Nakayama, Yasumune; Mukai, Yukio; Bamba, Takeshi; Fukusaki, Eiichiro

    2016-04-01

    The budding yeast Saccharomyces cerevisiae is widely used for brewing and ethanol production. The ethanol sensitivity of yeast cells is still a serious problem during ethanol fermentation, and a variety of genetic approaches (e.g., random mutant screening under selective pressure of ethanol) have been developed to improve ethanol tolerance. In this study, we developed a strategy for improving ethanol tolerance of yeast cells based on metabolomics as a high-resolution quantitative phenotypic analysis. We performed gas chromatography-mass spectrometry analysis to identify and quantify 36 compounds on 14 mutant strains including knockout strains for transcription factor and metabolic enzyme genes. A strong relation between metabolome of these mutants and their ethanol tolerance was observed. Data mining of the metabolomic analysis showed that several compounds (such as trehalose, valine, inositol and proline) contributed highly to ethanol tolerance. Our approach successfully detected well-known ethanol stress related metabolites such as trehalose and proline thus, to further prove our strategy, we focused on valine and inositol as the most promising target metabolites in our study. Our results show that simultaneous deletion of LEU4 and LEU9 (leading to accumulation of valine) or INM1 and INM2 (leading to reduction of inositol) significantly enhanced ethanol tolerance. This study shows the potential of the metabolomic approach to identify target genes for strain improvement of S. cerevisiae with higher ethanol tolerance.

  12. Global analysis of WRKY transcription factor superfamily in Setaria identifies potential candidates involved in abiotic stress signalling

    Directory of Open Access Journals (Sweden)

    Mehanathan eMuthamilarasan

    2015-10-01

    Full Text Available Transcription factors (TFs are major players in stress signalling and constitute an integral part of signalling networks. Among the major TFs, WRKY proteins play pivotal roles in regulation of transcriptional reprogramming associated with stress responses. In view of this, genome- and transcriptome-wide identification of WRKY TF family was performed in the C4 model plants, Setaria italica (SiWRKY and S. viridis (SvWRKY, respectively. The study identified 105 SiWRKY and 44 SvWRKY proteins that were computationally analysed for their physicochemical properties. Sequence alignment and phylogenetic analysis classified these proteins into three major groups, namely I, II and III with majority of WRKY proteins belonging to group II (53 SiWRKY and 23 SvWRKY, followed by group III (39 SiWRKY and 11 SvWRKY and group I (10 SiWRKY and 6 SvWRKY. Group II proteins were further classified into 5 subgroups (IIa to IIe based on their phylogeny. Domain analysis showed the presence of WRKY motif and zinc finger-like structures in these proteins along with additional domains in a few proteins. All SiWRKY genes were physically mapped on the S. italica genome and their duplication analysis revealed that 10 and 8 gene pairs underwent tandem and segmental duplications, respectively. Comparative mapping of SiWRKY and SvWRKY genes in related C4 panicoid genomes demonstrated the orthologous relationships between these genomes. In silico expression analysis of SiWRKY and SvWRKY genes showed their differential expression patterns in different tissues and stress conditions. Expression profiling of candidate SiWRKY genes in response to stress (dehydration and salinity and hormone treatments (abscisic acid, salicylic acid and methyl jasmonate suggested the putative involvement of SiWRKY066 and SiWRKY082 in stress and hormone signalling. These genes could be potential candidates for further characterization to delineate their functional roles in abiotic stress signalling.

  13. Grafting as a tool to improve tolerance of vegetables to abiotic stresses : Thermal stress, water stress and organic pollutants

    NARCIS (Netherlands)

    Schwarz, Dietmar; Rouphael, Youssef; Colla, Giuseppe; Venema, Jan Henk

    2010-01-01

    Due to limited availability of arable land and the high market demand for vegetables around the world, cucurbit (cucumber, melon, and watermelon) and solanaceous (eggplant, pepper and tomato) crops are frequently cultivated under unfavourable soil and environmental conditions. These include thermal

  14. The negative effect of starvation and the positive effect of mild thermal stress on thermal tolerance of the red flour beetle, Tribolium castaneum.

    Science.gov (United States)

    Scharf, Inon; Wexler, Yonatan; MacMillan, Heath Andrew; Presman, Shira; Simson, Eddie; Rosenstein, Shai

    2016-04-01

    The thermal tolerance of a terrestrial insect species can vary as a result of differences in population origin, developmental stage, age, and sex, as well as via phenotypic plasticity induced in response to changes in the abiotic environment. Here, we studied the effects of both starvation and mild cold and heat shocks on the thermal tolerance of the red flour beetle, Tribolium castaneum. Starvation led to impaired cold tolerance, measured as chill coma recovery time, and this effect, which was stronger in males than females, persisted for longer than 2 days but less than 7 days. Heat tolerance, measured as heat knockdown time, was not affected by starvation. Our results highlight the difficulty faced by insects when encountering multiple stressors simultaneously and indicate physiological trade-offs. Both mild cold and heat shocks led to improved heat tolerance in both sexes. It could be that both mild shocks lead to the expression of heat shock proteins, enhancing heat tolerance in the short run. Cold tolerance was not affected by previous mild cold shock, suggesting that such a cold shock, as a single event, causes little stress and hence elicits only weak physiological reaction. However, previous mild heat stress led to improved cold tolerance but only in males. Our results point to both hardening and cross-tolerance between cold and heat shocks.

  15. The negative effect of starvation and the positive effect of mild thermal stress on thermal tolerance of the red flour beetle, Tribolium castaneum

    Science.gov (United States)

    Scharf, Inon; Wexler, Yonatan; MacMillan, Heath Andrew; Presman, Shira; Simson, Eddie; Rosenstein, Shai

    2016-04-01

    The thermal tolerance of a terrestrial insect species can vary as a result of differences in population origin, developmental stage, age, and sex, as well as via phenotypic plasticity induced in response to changes in the abiotic environment. Here, we studied the effects of both starvation and mild cold and heat shocks on the thermal tolerance of the red flour beetle, Tribolium castaneum. Starvation led to impaired cold tolerance, measured as chill coma recovery time, and this effect, which was stronger in males than females, persisted for longer than 2 days but less than 7 days. Heat tolerance, measured as heat knockdown time, was not affected by starvation. Our results highlight the difficulty faced by insects when encountering multiple stressors simultaneously and indicate physiological trade-offs. Both mild cold and heat shocks led to improved heat tolerance in both sexes. It could be that both mild shocks lead to the expression of heat shock proteins, enhancing heat tolerance in the short run. Cold tolerance was not affected by previous mild cold shock, suggesting that such a cold shock, as a single event, causes little stress and hence elicits only weak physiological reaction. However, previous mild heat stress led to improved cold tolerance but only in males. Our results point to both hardening and cross-tolerance between cold and heat shocks.

  16. Impact of bacterial priming on some stress tolerance mechanisms and growth of cold stressed wheat seedlings

    Directory of Open Access Journals (Sweden)

    Mohammed E.H. Osman

    2014-01-01

    Full Text Available The potential to enhance growth of cold stressed wheat by seed treatment (priming with the beneficial bacteria Bacillus amyloliquefaciens 5113 and Azospirillum brasilense NO40 were tested. Results showed an improved ability of bacteria-treated seedlings to survive at −5°C up to 12 h. Cold stress increased transcript levels of three stress marker genes and increased activity for the ascorbate-glutathione redox enzymes. However, primed and stressed seedlings generally showed smaller effects on the stress markers correlating with better growth and improved stress tolerance. Bacterial priming to improve crop plant performance at low temperature seems a useful strategy to explore further.

  17. Expression analysis of a novel pyridoxal kinase messenger RNA splice variant, PKL, in oil rape suffering abiotic stress and phytohormones

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Pyridoxal kinase is key enzyme for the biosynthesis of pyridoxal 5'-phosphate, the biologically active form of vitamin B6, in the salvage pathway. A pyridoxal kinase gene, BnPKL (GenBank accession No. DQ463962), was isolated from oilseed rape (Brassica napus L.) following water stress through rapid amplification of complementary DNA (cDNA) ends. The results showed that the gene had two splice variants: PKL and PKL2. PKL, the long cDNA, encodes a 334 amino acid protein with a complete ATP-binding site, pyridoxai kinase-binding site and dimer interface site of a pyridoxal kinase, while PKL2, the short cDNA, lacked a partial domain. Southern blot showed that there were two copies in Brassica napus. The expression of BnPKL cDNA could rescue the mutant phenotype of Escherichia coil defective in pyridoxai kinase. Real-time reverse transcription-polymerase chain reaction revealed that the relative abundance of two transcripts are modulated by development and environmental stresses.Abscisic acid and NaCI were inclined to decrease PKL expression, but HO and cold temperatures induced the PKL expression. In addition, the PKL expression could be transiently induced by jasmonate acid at an early stage, abscisic acid, salicylic acid and jasmonate acid enhanced the PKL expression in roots. Our results demonstrated that BnPKL was a pyridoxal kinase involved in responses to biotic and abiotic stresses.

  18. Trichoderma species mediated differential tolerance against biotic stress of phytopathogens in Cicer arietinum L.

    Science.gov (United States)

    Saxena, Amrita; Raghuwanshi, Richa; Singh, Harikesh Bahadur

    2015-02-01

    Trichoderma spp. have been reported to aid in imparting biotic as well as abiotic tolerance to plants. However, there are only few reports unfolding the differential ability of separate species of Trichoderma genera generally exploited for their biocontrol potential in this framework. A study was undertaken to evaluate the biocontrol potential of different Trichoderma species namely T. harzianum, T. asperellum, T. koningiopsis, T. longibrachiatum, and T. aureoviride as identified in the group of indigenous isolates from the agricultural soils of Eastern Uttar Pradesh, India. Their biocontrol potential against three major soilborne phytopathogens, i.e., Sclerotium rolfsii, Sclerotinia sclerotiorum, and Colletotrichum capsici was confirmed by dual culture plate technique. Efficient mycoparasitic ability was further assessed in all the isolates in relation to chitinase, β-1,3 glucanase, pectinase, lipase, amylase, and cellulase production while equally consistent results were obtained for their probable phosphate solubilization and indole acetic acid (IAA) production abilities. The selected isolates were further subjected to test their ability to promote plant growth, to reduce disease incidence and to tolerate biotic stress in terms of lignification pattern against S. rolfsii in chickpea plants. Among the identified Trichoderma species, excellent results were observed for T. harzianum and T. koningiopsis indicating better biocontrol potential of these species in the group and thus exhibiting perspective for their commercial exploitation.

  19. [Salt stress tolerance of cucumber-grafted rootstocks].

    Science.gov (United States)

    Wang, Li-Ping; Sun, Jin; Guo, Shi-Rong; Liu, Shu-Ren; Liu, Chao-Jie; Tian, Jing

    2012-05-01

    Taking 4 different Cucurbita maxima x C. moschata rootstocks for cucumber (Cucumis sativus) as test materials, a solution culture experiment was conducted to study their growth and antioxidative enzyme activities under the stresses of Ca(NO3)2 and NaCl, with the salt stress tolerance of the rootstocks evaluated by subordinate function. At 30 mmol x L(-1) of Ca (NO3)2 or 45 mmol x L(-1) of NaCl, the growth of the rootstock seedlings was improved; but at 60 and 120 mmol x L(-1) of Ca(NO3)2 or 90 and 180 mmol x L(-1) of NaCl, the growth and the antioxidative systems of the seedlings were inhibited, and the salt injury index of 'Qingzhen No. 1' was the smallest, with the decrement of biomass and SOD, POD and CAT activities and the increment of relative conductance being significantly lower than those of the others. Under the stress of high concentration Ca(NO3)2, the SOD, POD and CAT activities of test rootstocks were higher, and the salt injury index and relative conductance were lower, as compared with those under high concentration NaCl, suggesting that the damage of Ca(NO3)2 stress to cucumber-grafted rootstock were smaller than that of NaCl stress. Among the 4 rootstocks, 'Qingzhen No. 1' had the strongest salt stress tolerance, followed by 'Zuomu Nangua', 'Fengyuan Tiejia', and 'Chaoba Nangua'.

  20. Genetic mechanisms of abiotic stress tolerance that translate to crop yield stability

    NARCIS (Netherlands)

    Mickelbart, Michael V; Hasegawa, Paul M; Bailey, Julia

    2015-01-01

    Crop yield reduction as a consequence of increasingly severe climatic events threatens global food security. Genetic loci that ensure productivity in challenging environments exist within the germplasm of crops, their wild relatives and species that are adapted to extreme environments. Selective bre

  1. Developing fiber specific promoter-reporter transgenic lines to study the effect of abiotic stresses on fiber development in cotton.

    Directory of Open Access Journals (Sweden)

    Junping Chen

    Full Text Available Cotton is one of the most important cash crops in US agricultural industry. Environmental stresses, such as drought, high temperature and combination of both, not only reduce the overall growth of cotton plants, but also greatly decrease cotton lint yield and fiber quality. The impact of environmental stresses on fiber development is poorly understood due to technical difficulties associated with the study of developing fiber tissues and lack of genetic materials to study fiber development. To address this important question and provide the need for scientific community, we have generated transgenic cotton lines harboring cotton fiber specific promoter (CFSP-reporter constructs from six cotton fiber specific genes (Expansin, E6, Rac13, CelA1, LTP, and Fb late, representing genes that are expressed at different stages of fiber development. Individual CFSP::GUS or CFSP::GFP construct was introduced into Coker 312 via Agrobacterium mediated transformation. Transgenic cotton lines were evaluated phenotypically and screened for the presence of selectable marker, reporter gene expression, and insertion numbers. Quantitative analysis showed that the patterns of GUS reporter gene activity during fiber development in transgenic cotton lines were similar to those of the native genes. Greenhouse drought and heat stress study showed a correlation between the decrease in promoter activities and decrease in fiber length, increase in micronaire and changes in other fiber quality traits in transgenic lines grown under stressed condition. These newly developed materials provide new molecular tools for studying the effects of abiotic stresses on fiber development and may be used in study of cotton fiber development genes and eventually in the genetic manipulation of fiber quality.

  2. Mechanisms of plant-plant interactions: concealment from herbivores is more important than abiotic-stress mediation in an African savannah.

    Science.gov (United States)

    Louthan, Allison M; Doak, Daniel F; Goheen, Jacob R; Palmer, Todd M; Pringle, Robert M

    2014-04-07

    Recent work on facilitative plant-plant interactions has emphasized the importance of neighbours' amelioration of abiotic stress, but the facilitative effects of neighbours in reducing plant apparency to herbivores have received less attention. Whereas theory on stress reduction predicts that competition should be more important in less stressful conditions, with facilitation becoming more important in harsh environments, apparency theory suggests that facilitation should be greater in the presence of herbivores, where it is disadvantageous to be conspicuous regardless of abiotic stress level. We tested the relative strength of neighbours' stress reduction versus apparency reduction on survival, growth, reproduction and lifetime fitness of Hibiscus meyeri, a common forb in central Kenya, using neighbour removals conducted inside and outside large-herbivore exclosures replicated in arid and mesic sites. In the absence of herbivores, neighbours competed with H. meyeri in mesic areas and facilitated H. meyeri in arid areas, as predicted by stress-reduction mechanisms. By contrast, neighbours facilitated H. meyeri in the presence of herbivory, regardless of aridity level, consistent with plant apparency. Our results show that the facilitative effects arising from plant apparency are stronger than the effects arising from abiotic stress reduction in this system, suggesting that plant-apparency effects may be particularly important in systems with extant large-herbivore communities.

  3. Improvement of Arabidopsis Biomass and Cold, Drought and Salinity Stress Tolerance by Modified Circadian Clock-Associated PSEUDO-RESPONSE REGULATORs.

    Science.gov (United States)

    Nakamichi, Norihito; Takao, Saori; Kudo, Toru; Kiba, Takatoshi; Wang, Yin; Kinoshita, Toshinori; Sakakibara, Hitoshi

    2016-05-01

    Plant circadian clocks control the timing of a variety of genetic, metabolic and physiological processes. Recent studies revealed a possible molecular mechanism for circadian clock regulation. Arabidopsis thaliana (Arabidopsis) PSEUDO-RESPONSE REGULATOR (PRR) genes, including TIMING OF CAB EXPRESSION 1 (TOC1), encode clock-associated transcriptional repressors that act redundantly. Disruption of multiple PRR genes results in drastic phenotypes, including increased biomass and abiotic stress tolerance, whereas PRR single mutants show subtle phenotypic differences due to genetic redundancy. In this study, we demonstrate that constitutive expression of engineered PRR5 (PRR5-VP), which functions as a transcriptional activator, can increase biomass and abiotic stress tolerance, similar to prr multiple mutants. Concomitant analyses of relative growth rate, flowering time and photosynthetic activity suggested that increased biomass of PRR5-VP plants is mostly due to late flowering, rather than to alterations in photosynthetic activity or growth rate. In addition, genome-wide gene expression profiling revealed that genes related to cold stress and water deprivation responses were up-regulated in PRR5-VP plants. PRR5-VP plants were more resistant to cold, drought and salinity stress than the wild type, whereas ft tsf and gi, well-known late flowering and increased biomass mutants, were not. These findings suggest that attenuation of PRR function by a single transformation of PRR-VP is a valuable method for increasing biomass as well as abiotic stress tolerance in Arabidopsis. Because the PRR gene family is conserved in vascular plants, PRR-VP may regulate biomass and stress responses in many plants, but especially in long-day annual plants.

  4. Overexpression of SlGMEs leads to ascorbate accumulation with enhanced oxidative stress, cold, and salt tolerance in tomato.

    Science.gov (United States)

    Zhang, Chanjuan; Liu, Junxia; Zhang, Yuyang; Cai, Xiaofeng; Gong, Pengjuan; Zhang, Junhong; Wang, Taotao; Li, Hanxia; Ye, Zhibiao

    2011-03-01

    GDP-Mannose 3',5'-epimerase (GME; EC 5.1.3.18) catalyses the conversion of GDP-D-mannose to GDP-L-galactose, an important step in the ascorbic acid (AsA) biosynthesis pathway in higher plants. In this study, two members of the GME gene family were isolated from tomato (Solanum lycopersicum). Both SlGME genes encode 376 amino acids and share a 92% similarity with each other. Semi-quantitative RT-PCR indicated that SlGME1 was constantly expressed in various tissues, whereas SlGME2 was differentially expressed in different tissues. Transient expression of fused SlGME1-GFP (green fluorescent protein) and SlGME2-GFP in onion cells revealed the cytoplasmic localisation of the two proteins. Transgenic plants over-expressing SlGME1 and SlGME2 exhibited a significant increase in total ascorbic acid in leaves and red fruits compared with wild-type plants. They also showed enhanced stress tolerance based on less chlorophyll content loss and membrane-lipid peroxidation under methyl viologen (paraquat) stress, higher survival rate under cold stress, and significantly higher seed germination rate, fresh weight, and root length under salt stress. The present study demonstrates that the overexpression of two members of the GME gene family resulted in increased ascorbate accumulation in tomato and improved tolerance to abiotic stresses.

  5. Transgenic rice expressing a cassava (Manihot esculenta Crantz) plasma membrane gene MePMP3-2 exhibits enhanced tolerance to salt and drought stresses.

    Science.gov (United States)

    Yu, Y; Cui, Y C; Ren, C; Rocha, P S C F; Peng, M; Xu, G Y; Wang, M L; Xia, X J

    2016-01-01

    Plasma membrane proteolipid 3 (PMP3) is a class of small hydrophobic proteins found in many organisms including higher plants. Some plant PMP3 genes have been shown to respond to abiotic stresses and to participate in the processes of plant stress tolerance. In this study, we isolated the cassava (Manihot esculenta Crantz) MePMP3-2 gene and functionally characterized its role in tolerance to abiotic stress by expressing it in rice (Oryza sativa L.). MePMP3-2 encodes a 77-amino acid protein belonging to a subgroup of plant PMP3s that have long hydrophylic C-terminal tails of unknown function. In silico analysis and co-localization studies indicated that MePMP3-2 is a plasma membrane protein with two transmembrane domains, similar to other PMP3s. In cassava leaves, MePMP3-2 expression was up-regulated by salt and drought stresses. Heterologous constitutive expression of MePMP3-2 in rice did not alter plant growth and development but increased tolerance to salt and drought stresses. In addition, under stress conditions MePMP3-2 transgenic plants accumulated less malondialdehyde, had increased levels of proline, and exhibited greater up-regulation of the stress-related genes OsProT and OsP5CS, but led to only minor changes in OsDREB2A and OsLEA3 expression. These findings indicate that MePMP3-2 may play an important role in salt and drought stress tolerance in transgenic rice.

  6. Evaluation of tolerance to water stress in beans

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    Mauricio Marini Köop

    2012-09-01

    Full Text Available The goal of this study was to evaluate the genotypes of beans, and to sort them into groups that are tolerant and sensitive to water stress, by assessing their morphological characteristics for use in blocks of crosses and the study of gene expression. We evaluated nine bean genotypes: IAPAR 14, IAPAR 81, Pérola, IPR Colibri, IPR Juriti, IPR Chopim, IPR Gralha, and IPR Tiziu IPR Uirapuru. The genotypes were subjected to two irrigation conditions: i irrigation water as needed throughout the culture cycle and ii irrigation water as needed until the appearance of the first bud, followed by no irrigation water for 15 days. The experimental design was in randomized blocks with three replications. The characteristics evaluated were: i plant height; ii stem diameter, iii number of pods per plant, iv number of grains per pod, v root length and vi root dry mass. Stem diameter should not be used to determine if bean genotypes are tolerant or susceptible to water shortages. The results for the Pérola genotype were the highest for most of the characteristics evaluated, and, for this reason, it was classified as tolerant to water stress during flowering. The genotypes IAPAR and 81 IPR Juriti had the lowest results for the most features and were classified as susceptible to water stress during flowering.

  7. Constitutive expression of CaXTH3, a hot pepper xyloglucan endotransglucosylase/hydrolase, enhanced tolerance to salt and drought stresses without phenotypic defects in tomato plants (Solanum lycopersicum cv. Dotaerang).

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    Choi, Jun Young; Seo, Young Sam; Kim, Su Jin; Kim, Woo Taek; Shin, Jeong Sheop

    2011-05-01

    The hot pepper xyloglucan endo-trans-gluco-sylase/hydrolase (CaXTH3) gene that was inducible by a broad spectrum of abiotic stresses in hot pepper has been reported to enhance tolerance to drought and high salinity in transgenic Arabidopsis. To assess whether CaXTH3 is a practically useful target gene for improving the stress tolerance of crop plants, we ectopically over-expressed the full-length CaXTH3 cDNA in tomato (Solanum lycopersicum cv. Dotaerang) and found that the 35S:CaXTH3 transgenic tomato plants exhibited a markedly increased tolerance to salt and drought stresses. Transgenic tomato plants exposed to a salt stress of 100 mM NaCl retained the chlorophyll in their leaves and showed normal root elongation. They also remained green and unwithered following exposure to 2 weeks of dehydration. A high proportion of stomatal closures in 35S:CaXTH3 was likely to be conferred by increased cell-wall remodeling activity of CaXTH3 in guard cell, which may reduce transpirational water loss in response to dehydration stress. Despite this increased stress tolerance, the transgenic tomato plants showed no detectable phenotype defects, such as abnormal morphology and growth retardation, under normal growth conditions. These results raise the possibility that CaXTH3 gene is appropriate for application in genetic engineering strategies aimed at improving abiotic stress tolerance in agriculturally and economically valuable crop plants.

  8. Coupled expression of Cu/Zn-superoxide dismutase and catalase in cassava improves tolerance against cold and drought stresses.

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    Xu, Jia; Duan, Xiaoguang; Yang, Jun; Beeching, John R; Zhang, Peng

    2013-06-01

    Recently we reported that the joint expression of cassava Cu/Zn superoxide dismutase (MeCu/ZnSOD) and catalase (MeCAT1) prolonged the shelf life of cassava storage-roots by the stabilization of reactive oxygen species (ROS) homeostasis after harvest. Since oxidative damage is a major feature of plants exposed to environmental stresses, transgenic cassava showing increased expression of the cytosolic MeCu/ZnSOD and the peroxisomal MeCAT1 should have improved resistance against other abiotic stresses. After cold treatment, the transgenic cassava maintained higher SOD and CAT activities and lower malendialdehyde content than those of wild type plants (WT). Detached leaves of transgenic cassava also showed slower transpirational water loss than those of WT. When plants were not watered for 30 d, transgenic lines exhibited a significant increase in water retention ability, accumulated 13% more proline and 12% less malendialdehyde than WT's, and showed enhanced activity of SOD and CAT. These results imply that manipulation of the antioxidative mechanism allows the development of staple crops with improved tolerance to abiotic stresses.

  9. Overexpression of the NDR1/HIN1-Like Gene NHL6 Modifies Seed Germination in Response to Abscisic Acid and Abiotic Stresses in Arabidopsis.

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    Bao, Yan; Song, Wei-Meng; Pan, Jing; Jiang, Chun-Mei; Srivastava, Renu; Li, Bei; Zhu, Lu-Ying; Su, Hong-Yan; Gao, Xiao-Shu; Liu, Hua; Yu, Xiang; Yang, Lei; Cheng, Xian-Hao; Zhang, Hong-Xia

    2016-01-01

    NHL (NDR1/HIN1-like) genes play crucial roles in pathogen induced plant responses to biotic stress. Here, we report the possible function of NHL6 in plant response to abscisic acid (ABA) and abiotic stress. NHL6 was highly expressed in non-germinated seeds, and its expression was strongly induced by ABA and multiple abiotic stress signals. Loss-of-function of NHL6 decreased sensitivity to ABA in the early developmental stages including seed germination and post-germination seedling growth of the nhl6 mutants. However, overexpression of NHL6 increased sensitivity to ABA, salt and osmotic stress of the transgenic plants. Further studies indicated that the increased sensitivity in the 35S::NHL6 overexpressing plants could be a result of both ABA hypersensitivity and increased endogenous ABA accumulation under the stress conditions. It was also seen that the ABA-responsive element binding factors AREB1, AREB2 and ABF3 could regulate NHL6 expression at transcriptional level. Our results indicate that NHL6 plays an important role in the abiotic stresses-induced ABA signaling and biosynthesis, particularly during seed germination and early seedling development in Arabidopsis.

  10. TaSCL14, a novel wheat (Triticum aestivum L.) GRAS gene, regulates plant growth, photosynthesis, tolerance to photooxidative stress, and senescence.

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    Chen, Kunmei; Li, Hongwei; Chen, Yaofeng; Zheng, Qi; Li, Bin; Li, Zhensheng

    2015-01-20

    Rates of photosynthesis, tolerance to photooxidative stress, and senescence are all important physiological factors that affect plant development and thus agricultural productivity. GRAS proteins play essential roles in plant growth and development as well as in plant responses to biotic and abiotic stresses. So far few GRAS genes in wheat (Triticum aestivum L.) have been characterized. A previous transcriptome analysis indicated that the expression of a GRAS gene (TaSCL14) was induced by high-light stress in Xiaoyan 54 (XY54), a common wheat cultivar with strong tolerance to high-light stress. In this study, TaSCL14 gene was isolated from XY54 and mapped on chromosome 4A. TaSCL14 was expressed in various wheat organs, with high levels in stems and roots. Our results confirmed that TaSCL14 expression was indeed responsive to high-light stress. Barley stripe mosaic virus (BSMV)-based virus-induced gene silencing (VIGS) of TaSCL14 in wheat was performed to help characterize its potential functions. Silencing of TaSCL14 resulted in inhibited plant growth, decreased photosynthetic capacity, and reduced tolerance to photooxidative stress. In addition, silencing of TaSCL14 in wheat promoted leaf senescence induced by darkness. These results suggest that TaSCL14 may act as a multifunctional regulator involved in plant growth, photosynthesis, tolerance to photooxidative stress, and senescence.

  11. Reference gene selection for quantitative real-time PCR normalization in Caragana intermedia under different abiotic stress conditions.

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    Zhu, Jianfeng; Zhang, Lifeng; Li, Wanfeng; Han, Suying; Yang, Wenhua; Qi, Liwang

    2013-01-01

    Quantitative real-time reverse transcription polymerase chain reaction (qPCR), a sensitive technique for gene expression analysis, depends on the stability of the reference genes used for data normalization. Caragana intermedia, a native desert shrub with strong drought-resistance, sand-fixing capacity and high forage value that is widespread in the desert land of west and northwest China, has not been investigated regarding the identification of reference genes suitable for the normalization of qPCR data. In this study, 10 candidate reference genes were analyzed in C. intermedia subjected to different abiotic (osmotic, salt, cold and heat) stresses, in two distinct plant organs (roots and leaves). The expression stability of these genes was assessed using geNorm, NormFinder and BestKeeper algorithms. The best-ranked reference genes differed across the different sets of samples, but UNK2, PP2A and SAND were the most stable across all tested samples. UNK2 and SAND would be appropriate for normalizing gene expression data for salt-treated roots, whereas the combination of UNK2, SAND and EF-1α would be appropriate for salt-treated leaves. UNK1, UNK2 and PP2A would be appropriate for PEG-treated (osmotic) roots, whereas the combination of TIP41 and PP2A was the most suitable for PEG-treated leaves. SAND, PP2A and TIP41 exhibited the most stable expression in heat-treated leaves. In cold-treated leaves, SAND and EF-1α were the most stably expressed. To further validate the suitability of the reference genes identified in this study, the expression levels of DREB1 and DREB2 (homologs of AtDREB1 and AtDREB2) were studied in parallel. This study is the first systematic analysis for the selection of superior reference genes for qPCR in C. intermedia under different abiotic stress conditions, and will benefit future studies on gene expression in C. intermedia and other species of the leguminous genus Caragana.

  12. Coral thermal tolerance: tuning gene expression to resist thermal stress.

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    Anthony J Bellantuono

    Full Text Available The acclimatization capacity of corals is a critical consideration in the persistence of coral reefs under stresses imposed by global climate change. The stress history of corals plays a role in subsequent response to heat stress, but the transcriptomic changes associated with these plastic changes have not been previously explored. In order to identify host transcriptomic changes associated with acquired thermal tolerance in the scleractinian coral Acropora millepora, corals preconditioned to a sub-lethal temperature of 3°C below bleaching threshold temperature were compared to both non-preconditioned corals and untreated controls using a cDNA microarray platform. After eight days of hyperthermal challenge, conditions under which non-preconditioned corals bleached and preconditioned corals (thermal-tolerant maintained Symbiodinium density, a clear differentiation in the transcriptional profiles was revealed among the condition examined. Among these changes, nine differentially expressed genes separated preconditioned corals from non-preconditioned corals, with 42 genes differentially expressed between control and preconditioned treatments, and 70 genes between non-preconditioned corals and controls. Differentially expressed genes included components of an apoptotic signaling cascade, which suggest the inhibition of apoptosis in preconditioned corals. Additionally, lectins and genes involved in response to oxidative stress were also detected. One dominant pattern was the apparent tuning of gene expression observed between preconditioned and non-preconditioned treatments; that is, differences in expression magnitude were more apparent than differences in the identity of genes differentially expressed. Our work revealed a transcriptomic signature underlying the tolerance associated with coral thermal history, and suggests that understanding the molecular mechanisms behind physiological acclimatization would be critical for the modeling of reefs

  13. Emerging concept for the role of photorespiration as an important part of abiotic stress response.

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    Voss, I; Sunil, B; Scheibe, R; Raghavendra, A S

    2013-07-01

    When plants are exposed to stress, generation of reactive oxygen species (ROS) is often one of the first responses. In order to survive, cells attempt to down-regulate the production of ROS, while at the same time scavenging ROS. Photorespiration is now appreciated as an important part of stress responses in green tissues for preventing ROS accumulation. Photorespiratory reactions can dissipate excess reducing equivalents and energy either directly (using ATP, NAD(P)H and reduced ferredoxin) or indirectly (e.g., via alternative oxidase (AOX) and providing an internal CO2 pool). Photorespiration, however, is also a source of H2 O2 that is possibly involved in signal transduction, resulting in modulation of gene expression. We propose that photorespiration can assume a major role in the readjustment of redox homeostasis. Protection of photosynthesis from photoinhibition through photorespiration is well known. Photorespiration can mitigate oxidative stress under conditions of drought/water stress, salinity, low CO2 and chilling. Adjustments to even mild disturbances in redox status, caused by a deficiency in ascorbate, AOX or chloroplastic NADP-malate dehydrogenase, comprise increases in photorespiratory components such as catalase, P-protein of glycine decarboxylase complex (GDC) and glycine content. The accumulation of excess reducing equivalents or ROS in plant cells also affects mitochondria. Therefore, a strong interaction between the chloroplast redox status and photorespiration is not surprising, but highlights interesting properties evident in plant cells. We draw attention to the fact that a complex network of multiple and dynamic systems, including photorespiration, prevents oxidative damage while optimising photosynthesis. Further experiments are necessary to identify and validate the direct targets of redox signals among photorespiratory components.

  14. Identification of 14-3-3 Family in Common Bean and Their Response to Abiotic Stress.

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    Ruihua Li

    Full Text Available 14-3-3s are a class of conserved regulatory proteins ubiquitously found in eukaryotes, which play important roles in a variety of cellular processes including response to diverse stresses. Although much has been learned about 14-3-3s in several plant species, it remains unknown in common bean. In this study, 9 common bean 14-3-3s (PvGF14s were identified by exhaustive data mining against the publicly available common bean genomic database. A phylogenetic analysis revealed that each predicted PvGF14 was clustered with two GmSGF14 paralogs from soybean. Both epsilon-like and non-epsilon classes of PvGF14s were found in common bean, and the PvGF14s belonging to each class exhibited similar gene structure. Among 9 PvGF14s, only 8 are transcribed in common bean. Expression patterns of PvGF14s varied depending on tissue type, developmental stage and exposure of plants to stress. A protein-protein interaction study revealed that PvGF14a forms dimer with itself and with other PvGF14 isoforms. This study provides a first comprehensive look at common bean 14-3-3 proteins, a family of proteins with diverse functions in many cellular processes, especially in response to stresses.

  15. Field Phenotyping of Soybean Roots for Drought Stress Tolerance

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    Berhanu A. Fenta

    2014-08-01

    Full Text Available Root architecture was determined together with shoot parameters under well watered and drought conditions in the field in three soybean cultivars (A5409RG, Jackson and Prima 2000. Morphology parameters were used to classify the cultivars into different root phenotypes that could be important in conferring drought tolerance traits. A5409RG is a drought-sensitive cultivar with a shallow root phenotype and a root angle of <40°. In contrast, Jackson is a drought-escaping cultivar. It has a deep rooting phenotype with a root angle of >60°. Prima 2000 is an intermediate drought-tolerant cultivar with a root angle of 40°–60°. It has an intermediate root phenotype. Prima 2000 was the best performing cultivar under drought stress, having the greatest shoot biomass and grain yield under limited water availability. It had abundant root nodules even under drought conditions. A positive correlation was observed between nodule size, above-ground biomass and seed yield under well-watered and drought conditions. These findings demonstrate that root system phenotyping using markers that are easy-to-apply under field conditions can be used to determine genotypic differences in drought tolerance in soybean. The strong association between root and nodule parameters and whole plant productivity demonstrates the potential application of simple root phenotypic markers in screening for drought tolerance in soybean.

  16. Characterization of the Nrt2.6 gene in Arabidopsis thaliana: a link with plant response to biotic and abiotic stress.

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    Julie Dechorgnat

    Full Text Available The high affinity nitrate transport system in Arabidopsis thaliana involves one gene and potentially seven genes from the NRT1 and NRT2 family, respectively. Among them, NRT2.1, NRT2.2, NRT2.4 and NRT2.7 proteins have been shown to transport nitrate and are localized on the plasmalemma or the tonoplast membranes. NRT2.1, NRT2.2 and NRT2.4 play a role in nitrate uptake from soil solution by root cells while NRT2.7 is responsible for nitrate loading in the seed vacuole. We have undertaken the functional characterization of a third member of the family, the NRT2.6 gene. NRT2.6 was weakly expressed in most plant organs and its expression was higher in vegetative organs than in reproductive organs. Contrary to other NRT2 members, NRT2.6 expression was not induced by limiting but rather by high nitrogen levels, and no nitrate-related phenotype was found in the nrt2.6-1 mutant. Consistently, the over-expression of the gene failed to complement the nitrate uptake defect of an nrt2.1-nrt2.2 double mutant. The NRT2.6 expression is induced after inoculation of Arabidopsis thaliana by the phytopathogenic bacterium Erwinia amylovora. Interestingly, plants with a decreased NRT2.6 expression showed a lower tolerance to pathogen attack. A correlation was found between NRT2.6 expression and ROS species accumulation in response to infection by E. amylovora and treatment with the redox-active herbicide methyl viologen, suggesting a probable link between NRT2.6 activity and the production of ROS in response to biotic and abiotic stress.

  17. Delayed germination of Arabidopsis seeds under chilling stress by overexpressing an abiotic stress inducible GhTPS11.

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    Wang, Cai-Li; Zhang, Shi-Cai; Qi, Sheng-Dong; Zheng, Cheng-Chao; Wu, Chang-Ai

    2016-01-10

    Trehalose-6-phosphate synthase (TPS) plays an important role in metabolic regulation and stress responses in a variety of organisms. However information about cotton TPS is poor. Here a cotton TPS gene GhTPS11 was isolated and characterized. Expression analysis revealed that GhTPS11 was induced in 20-day old cotton seedlings by heat drought and high salt stresses as well as GA and ABA. Moreover GhTPS11 was induced by chilling stress and mannitol while was depressed by sucrose. Tissue expression analysis indicated that GhTPS11 expressed higher in leaves than in stems and roots of 20-day old cotton seedlings. The GhTPS11 overexpressing Arabidopsis seeds germinated slower than the wild-type (WT) under chilling stress. Trehalose-6-phosphate (T6P) and trehalose contents were evidently higher in GhTPS11 overexpressing lines 3, 5, and 22 than in WT under normal germination condition as well as chilling stress. Further analysis demonstrated that the expression of ICE1 CBF3 and RCI2A was induced lower whereas that of CBF1 and CBF2 was induced higher under chilling stress in the GhTPS11 overexpressing seeds than WT respectively. These results suggested that GhTPS11 encoded a stress-responsive TPS protein and functioned in chilling stress during seed germination. Perhaps the chilling stress sensitivity of transgenic Arabidopsis seeds was caused by the expression changes of at least some chilling-related genes such as ICE1 CBFs and RCI2A other than HOS1. So this article provided the useful information for GhTPS11 usage for crop molecular breeding.

  18. The phenome analysis of mutant alleles in Leucine-Rich Repeat Receptor-Like Kinase genes in rice reveals new potential targets for stress tolerant cereals.

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    Dievart, Anne; Perin, Christophe; Hirsch, Judith; Bettembourg, Mathilde; Lanau, Nadège; Artus, Florence; Bureau, Charlotte; Noel, Nicolas; Droc, Gaétan; Peyramard, Matthieu; Pereira, Serge; Courtois, Brigitte; Morel, Jean-Benoit; Guiderdoni, Emmanuel

    2016-01-01

    Plants are constantly exposed to a variety of biotic and abiotic stresses that reduce their fitness and performance. At the molecular level, the perception of extracellular stimuli and the subsequent activation of defense responses require a complex interplay of signaling cascades, in which protein phosphorylation plays a central role. Several studies have shown that some members of the Leucine-Rich Repeat Receptor-Like Kinase (LRR-RLK) family are involved in stress and developmental pathways. We report here a systematic analysis of the role of the members of this gene family by mutant phenotyping in the monocotyledon model plant rice, Oryza sativa. We have then targeted 176 of the ∼320 LRR-RLK genes (55.7%) and genotyped 288 mutant lines. Position of the insertion was confirmed in 128 lines corresponding to 100 LRR-RLK genes (31.6% of the entire family). All mutant lines harboring homozygous insertions have been screened for phenotypes under normal conditions and under various abiotic stresses. Mutant plants have been observed at several stages of growth, from seedlings in Petri dishes to flowering and grain filling under greenhouse conditions. Our results show that 37 of the LRR-RLK rice genes are potential targets for improvement especially in the generation of abiotic stress tolerant cereals.

  19. Transgenic tobacco plants overexpressing a grass PpEXP1 gene exhibit enhanced tolerance to heat stress.

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    Qian Xu

    Full Text Available Heat stress is a detrimental abiotic stress limiting the growth of many plant species and is associated with various cellular and physiological damages. Expansins are a family of proteins which are known to play roles in regulating cell wall elongation and expansion, as well as other growth and developmental processes. The in vitro roles of expansins regulating plant heat tolerance are not well understood. The objectives of this study were to isolate and clone an expansin gene in a perennial grass species (Poa pratensis and to determine whether over-expression of expansin may improve plant heat tolerance. Tobacco (Nicotiana tabacum was used as the model plant for gene transformation and an expansin gene PpEXP1 from Poa pratensis was cloned. Sequence analysis showed PpEXP1 belonged to α-expansins and was closely related to two expansin genes in other perennial grass species (Festuca pratensis and Agrostis stolonifera as well as Triticum aestivum, Oryza sativa, and Brachypodium distachyon. Transgenic tobacco plants over-expressing PpEXP1 were generated through Agrobacterium-mediated transformation. Under heat stress (42°C in growth chambers, transgenic tobacco plants over-expressing the PpEXP1 gene exhibited a less structural damage to cells, lower electrolyte leakage, lower levels of membrane lipid peroxidation, and lower content of hydrogen peroxide, as well as higher chlorophyll content, net photosynthetic rate, relative water content, activity of antioxidant enzyme, and seed germination rates, compared to the wild-type plants. These results demonstrated the positive roles of PpEXP1 in enhancing plant tolerance to heat stress and the possibility of using expansins for genetic modification of cool-season perennial grasses in the development of heat-tolerant germplasm and cultivars.

  20. Photosynthetic response to fluctuating environments and photoprotective strategies under abiotic stress.

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    Yamori, Wataru

    2016-05-01

    Plants in natural environments must cope with diverse, highly dynamic, and unpredictable conditions. They have mechanisms to enhance the capture of light energy when light intensity is low, but they can also slow down photosynthetic electron transport to prevent the production of reactive oxygen species and consequent damage to the photosynthetic machinery under excess light. Plants need a highly responsive regulatory system to balance the photosynthetic light reactions with downstream metabolism. Various mechanisms of regulation of photosynthetic electron transport under stress have been proposed, however the data have been obtained mainly under environmentally stable and controlled conditions. Thus, our understanding of dynamic modulation of photosynthesis under dramatically fluctuating natural environments remains limited. In this review, first I describe the magnitude of environmental fluctuations under natural conditions. Next, I examine the effects of fluctuations in light intensity, CO2 concentration, leaf temperature, and relative humidity on dynamic photosynthesis. Finally, I summarize photoprotective strategies that allow plants to maintain the photosynthesis under stressful fluctuating environments. The present work clearly showed that fluctuation in various environmental factors resulted in reductions in photosynthetic rate in a stepwise manner at every environmental fluctuation, leading to the conclusion that fluctuating environments would have a large impact on photosynthesis.

  1. Nitrogen Assimilation, Abiotic Stress and Glucose 6-Phosphate Dehydrogenase: The Full Circle of Reductants.

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    Esposito, Sergio

    2016-05-11

    Glucose 6 phosphate dehydrogenase (G6PDH; EC 1.1.1.49) is well-known as the main regulatory enzyme of the oxidative pentose phosphate pathway (OPPP) in living organisms. Namely, in Planta, different G6PDH isoforms may occur, generally localized in cytosol and plastids/chloroplasts. These enzymes are differently regulated by distinct mechanisms, still far from being defined in detail. In the last decades, a pivotal function for plant G6PDHs during the assimilation of nitrogen, providing reductants for enzymes involved in nitrate reduction and ammonium assimilation, has been described. More recently, several studies have suggested a main role of G6PDH to counteract different stress conditions, among these salinity and drought, with the involvement of an ABA depending signal. In the last few years, this recognized vision has been greatly widened, due to studies clearly showing the non-conventional subcellular localization of the different G6PDHs, and the peculiar regulation of the different isoforms. The whole body of these considerations suggests a central question: how do the plant cells distribute the reductants coming from G6PDH and balance their equilibrium? This review explores the present knowledge about these mechanisms, in order to propose a scheme of distribution of reductants produced by G6PDH during nitrogen assimilation and stress.

  2. Volatile isoprenoids as defense compounds during abiotic stress in tropical plants

    Science.gov (United States)

    Jardine, K.

    2015-12-01

    Emissions of volatile isoprenoids from tropical forests play central roles in atmospheric processes by fueling atmospheric chemistry resulting in modified aerosol and cloud lifecycles and their associated feedbacks with the terrestrial biosphere. However, the identities of tropical isoprenoids, their biological and environmental controls, and functions within plants and ecosystems remain highly uncertain. As part of the DOE ARM program's GoAmazon 2014/15 campaign, extensive field and laboratory observations of volatile isoprenoids are being conducted in the central Amazon. Here we report the results of our completed and ongoing activities at the ZF2 forest reserve in the central Amazon. Among the results of the research are the suprisingly high abundance of light-dependent volatile isoprenoid emissions across abundant tree genera in the Amazon in both primary and secondary forests, the discovery of highly reactive monoterpene emissions from Amazon trees, and evidence for the importance of volatile isoprenoids in protecting photosynthesis during oxidative stress under elevated temperatures including energy consumption and direct antioxidant functions and a tight connection betwen volatile isoprenoid emissions, photorespiration, and CO2 recycling within leaves. The results highlight the need to model allocation of carbon to isoprenoids during elevated temperature stress in the tropics.

  3. Contribution of the drought tolerance-related stress-responsive NAC1 transcription factor to resistance of barley to Ramularia leaf spot.

    Science.gov (United States)

    McGrann, Graham R D; Steed, Andrew; Burt, Christopher; Goddard, Rachel; Lachaux, Clea; Bansal, Anuradha; Corbitt, Margaret; Gorniak, Kalina; Nicholson, Paul; Brown, James K M

    2015-02-01

    NAC proteins are plant transcription factors that are involved in tolerance to abiotic and biotic stresses, as well as in many developmental processes. Stress-responsive NAC1 (SNAC1) transcription factor is involved in drought tolerance in barley and rice, but has not been shown previously to have a role in disease resistance. Transgenic over-expression of HvSNAC1 in barley cv. Golden Promise reduced the severity of Ramularia leaf spot (RLS), caused by the fungus Ramularia collo-cygni, but had no effect on disease symptoms caused by Fusarium culmorum, Oculimacula yallundae (eyespot), Blumeria graminis f. sp. hordei (powdery mildew) or Magnaporthe oryzae (blast). The HvSNAC1 transcript was weakly induced in the RLS-susceptible cv. Golden Promise during the latter stages of R. collo-cygni symptom development when infected leaves were senescing. Potential mechanisms controlling HvSNAC1-mediated resistance to RLS were investigated. Gene expression analysis revealed no difference in the constitutive levels of antioxidant transcripts in either of the over-expression lines compared with cv. Golden Promise, nor was any difference in stomatal conductance or sensitivity to reactive oxygen species-induced cell death observed. Over-expression of HvSNAC1 delayed dark-induced leaf senescence. It is proposed that mechanisms controlled by HvSNAC1 that are involved in tolerance to abiotic stress and that inhibit senescence also confer resistance to R. collo-cygni and suppress RLS symptoms. This provides further evidence for an association between abiotic stress and senescence in barley and the development of RLS.

  4. Jasmonic acid distribution and action in plants: regulation during development and response to biotic and abiotic stress.

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    Creelman, R A; Mullet, J E

    1995-05-09

    Jasmonic acid (JA) is a naturally occurring growth regulator found in higher plants. Several physiological roles have been described for this compound (or a related compound, methyl jasmonate) during plant development and in response to biotic and abiotic stress. To accurately determine JA levels in plant tissue, we have synthesized JA containing 13C for use as an internal standard with an isotopic composition of [225]:[224] 0.98:0.02 compared with [225]:[224] 0.15:0.85 for natural material. GC analysis (flame ionization detection and MS) indicate that the internal standard is composed of 92% 2-(+/-)-[13C]JA and 8% 2-(+/-)-7-iso-[13C]JA. In soybean plants, JA levels were highest in young leaves, flowers, and fruit (highest in the pericarp). In soybean seeds and seedlings, JA levels were highest in the youngest organs including the hypocotyl hook, plumule, and 12-h axis. In soybean leaves that had been dehydrated to cause a 15% decrease in fresh weight, JA levels increased approximately 5-fold within 2 h and declined to approximately control levels by 4 h. In contrast, a lag time of 1-2 h occurred before abscisic acid accumulation reached a maximum. These results will be discussed in the context of multiple pathways for JA biosynthesis and the role of JA in plant development and responses to environmental signals.

  5. Enhanced drought and heat stress tolerance of tobacco plants with ectopically enhanced cytokinin oxidase/dehydrogenase gene expression.

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    Macková, Hana; Hronková, Marie; Dobrá, Jana; Turečková, Veronika; Novák, Ondřej; Lubovská, Zuzana; Motyka, Václav; Haisel, Daniel; Hájek, Tomáš; Prášil, Ilja Tom; Gaudinová, Alena; Štorchová, Helena; Ge, Eva; Werner, Tomáš; Schmülling, Thomas; Vanková, Radomíra

    2013-07-01

    Responses to drought, heat, and combined stress were compared in tobacco (Nicotiana tabacum L.) plants ectopically expressing the cytokinin oxidase/dehydrogenase CKX1 gene of Arabidopsis thaliana L. under the control of either the predominantly root-expressed WRKY6 promoter or the constitutive 35S promoter, and in the wild type. WRKY6:CKX1 plants exhibited high CKX activity in the roots under control conditions. Under stress, the activity of the WRKY6 promoter was down-regulated and the concomitantly reduced cytokinin degradation coincided with raised bioactive cytokinin levels during the early phase of the stress response, which might contribute to enhanced stress tolerance of this genotype. Constitutive expression of CKX1 resulted in an enlarged root system, a stunted, dwarf shoot phenotype, and a low basal level of expression of the dehydration marker gene ERD10B. The high drought tolerance of this genotype was associated with a relatively moderate drop in leaf water potential and a significant decrease in leaf osmotic potential. Basal expression of the proline biosynthetic gene P5CSA was raised. Both wild-type and WRKY6:CKX1 plants responded to heat stress by transient elevation of stomatal conductance, which correlated with an enhanced abscisic acid catabolism. 35S:CKX1 transgenic plants exhibited a small and delayed stomatal response. Nevertheless, they maintained a lower leaf temperature than the other genotypes. Heat shock applied to drought-stressed plants exaggerated the negative stress effects, probably due to the additional water loss caused by a transient stimulation of transpiration. The results indicate that modulation of cytokinin levels may positively affect plant responses to abiotic stress through a variety of physiological mechanisms.

  6. Reference gene validation for quantitative RT-PCR during biotic and abiotic stresses in Vitis vinifera.

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    Alexandre Filipe Borges

    Full Text Available Grapevine is one of the most cultivated fruit crop worldwide with Vitis vinifera being the species with the highest economical importance. Being highly susceptible to fungal pathogens and increasingly affected by environmental factors, it has become an important agricultural research area, where gene expression analysis plays a fundamental role. Quantitative reverse transcription polymerase chain reaction (qRT-PCR is currently amongst the most powerful techniques to perform gene expression studies. Nevertheless, accurate gene expression quantification strongly relies on appropriate reference gene selection for sample normalization. Concerning V. vinifera, limited information still exists as for which genes are the most suitable to be used as reference under particular experimental conditions. In this work, seven candidate genes were investigated for their stability in grapevine samples referring to four distinct stresses (Erysiphe necator, wounding and UV-C irradiation in leaves and Phaeomoniella chlamydospora colonization in wood. The expression stability was evaluated using geNorm, NormFinder and BestKeeper. In all cases, full agreement was not observed for the three methods. To provide comprehensive rankings integrating the three different programs, for each treatment, a consensus ranking was created using a non-weighted unsupervised rank aggregation method. According to the last, the three most suitable reference genes to be used in grapevine leaves, regardless of the stress, are UBC, VAG and PEP. For the P. chlamydospora treatment, EF1, CYP and UBC were the best scoring genes. Acquaintance of the most suitable reference genes to be used in grapevine samples can contribute for accurate gene expression quantification in forthcoming studies.