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

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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

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

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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

SALT TOLERANCE OF CROP PLANTS

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Hamdia, M. A

2010-09-01

Full Text Available Several environmental factors adversely affect plant growth and development and final yield performance of a crop. Drought, salinity, nutrient imbalances (including mineral toxicities and deficiencies and extremes of temperature are among the major environmental constraints to crop productivity worldwide. Development of crop plants with stress tolerance, however, requires, among others, knowledge of the physiological mechanisms and genetic controls of the contributing traits at different plant developmental stages. In the past 2 decades, biotechnology research has provided considerable insights into the mechanism of biotic stress tolerance in plants at the molecular level. Furthermore, different abiotic stress factors may provoke osmotic stress, oxidative stress and protein denaturation in plants, which lead to similar cellular adaptive responses such as accumulation of compatible solutes, induction of stress proteins, and acceleration of reactive oxygen species scavenging systems. Recently, the authores try to improve plant tolerance to salinity injury through either chemical treatments (plant hormones, minerals, amino acids, quaternary ammonium compounds, polyamines and vitamins or biofertilizers treatments (Asymbiotic nitrogen-fixing bacteria, symbiotic nitrogen-fixing bacteria and mycorrhiza or enhanced a process used naturally by plants to minimise the movement of Na+ to the shoot, using genetic modification to amplify the process, helping plants to do what they already do - but to do it much better."

Compositions and methods for providing plants with tolerance to abiotic stress conditions

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Hirt, Heribert; De Zelicourt, Axel; Saad, Maged

2017-01-01

It has been discovered that the desert endophytic bacterium SA187 SA187 can provide resistance or tolerance to abiotic stress conditions to seeds or plants. Compositions containing SA187 can be used to enhance plant development and yield under

The involvement of wheat F-box protein gene TaFBA1 in the oxidative stress tolerance of plants.

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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.

Manipulation of plant ethylene balance by soil microbiota: a holobiont perspective to stress tolerance

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Ravanbakhsh, Mohammadhossein

2018-01-01

Plants continuously adjust their physiology and phenotype to stressors. Plant hormones and modulators mediate the adaptation of the plant to changing environmental conditions by allocating resources precisely between growth and stress tolerance. Plant responses to stressors are typically studied

Overexpression of an Arabidopsis heterogeneous nuclear ribonucleoprotein gene, AtRNP1, affects plant growth and reduces plant tolerance to drought and salt stresses

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Wang, Zhenyu; Zhao, Xiuyang; Wang, Bing; Liu, Erlong; Chen, Ni; Zhang, Wei; Liu, Heng

2016-01-01

Heterogeneous nuclear ribonucleoproteins (hnRNPs) participate in diverse regulations of plant growth and environmental stress responses. In this work, an Arabidopsis hnRNP of unknown function, AtRNP1, was investigated. We found that AtRNP1 gene is highly expressed in rosette and cauline leaves, and slightly induced under drought, salt, osmotic and ABA stresses. AtRNP1 protein is localized to both the nucleus and cytoplasm. We performed homologous overexpression of AtRNP1 and found that the transgenic plants showed shortened root length and plant height, and accelerated flowering. In addition, the transgenic plants also showed reduced tolerance to drought, salt, osmotic and ABA stresses. Further studies revealed that under both normal and stress conditions, the proline contents in the transgenic plants are markedly decreased, associated with reduced expression levels of a proline synthase gene and several stress-responsive genes. These results suggested that the overexpression of AtRNP1 negatively affects plant growth and abiotic stress tolerance. - Highlights: • AtRNP1 is a widely expressed gene and its expression is slightly induced under abiotic stresses. • AtRNP1 protein is localized to both the nucleus and cytoplasm. • Overexpression of AtRNP1 affects plant growth. • Overexpression of AtRNP1 reduces plant tolerance to drought and salt stresses. • AtRNP1 overexpression plants show decreased proline accumulation and stress-responsive gene expressions.

Overexpression of an Arabidopsis heterogeneous nuclear ribonucleoprotein gene, AtRNP1, affects plant growth and reduces plant tolerance to drought and salt stresses

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhenyu, E-mail: wzy72609@163.com [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Zhao, Xiuyang, E-mail: xiuzh@psb.vib-ugent.be [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Wang, Bing, E-mail: wangbing@ibcas.ac.cn [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Liu, Erlong, E-mail: liuel14@lzu.edu.cn [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Chen, Ni, E-mail: 63710156@qq.com [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Zhang, Wei, E-mail: wzhang1216@yahoo.com [Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444 (China); Liu, Heng, E-mail: hengliu@lzu.edu.cn [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China)

2016-04-01

Heterogeneous nuclear ribonucleoproteins (hnRNPs) participate in diverse regulations of plant growth and environmental stress responses. In this work, an Arabidopsis hnRNP of unknown function, AtRNP1, was investigated. We found that AtRNP1 gene is highly expressed in rosette and cauline leaves, and slightly induced under drought, salt, osmotic and ABA stresses. AtRNP1 protein is localized to both the nucleus and cytoplasm. We performed homologous overexpression of AtRNP1 and found that the transgenic plants showed shortened root length and plant height, and accelerated flowering. In addition, the transgenic plants also showed reduced tolerance to drought, salt, osmotic and ABA stresses. Further studies revealed that under both normal and stress conditions, the proline contents in the transgenic plants are markedly decreased, associated with reduced expression levels of a proline synthase gene and several stress-responsive genes. These results suggested that the overexpression of AtRNP1 negatively affects plant growth and abiotic stress tolerance. - Highlights: • AtRNP1 is a widely expressed gene and its expression is slightly induced under abiotic stresses. • AtRNP1 protein is localized to both the nucleus and cytoplasm. • Overexpression of AtRNP1 affects plant growth. • Overexpression of AtRNP1 reduces plant tolerance to drought and salt stresses. • AtRNP1 overexpression plants show decreased proline accumulation and stress-responsive gene expressions.

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

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Vemanna S Ramu

Full Text Available 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.

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

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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. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Unravelling chemical priming machinery in plants: the role of reactive oxygen-nitrogen-sulfur species in abiotic stress tolerance enhancement.

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Antoniou, Chrystalla; Savvides, Andreas; Christou, Anastasis; Fotopoulos, Vasileios

2016-10-01

Abiotic stresses severely limit crop yield and their detrimental effects are aggravated by climate change. Chemical priming is an emerging field in crop stress management. The exogenous application of specific chemical agents before stress events results in tolerance enhancement and reduction of stress impacts on plant physiology and growth. However, the molecular mechanisms underlying the remarkable effects of chemical priming on plant physiology remain to be elucidated. Reactive oxygen, nitrogen and sulfur species (RONSS) are molecules playing a vital role in the stress acclimation of plants. When applied as priming agents, RONSS improve stress tolerance. This review summarizes the recent knowledge on the role of RONSS in cell signalling and gene regulation contributing to abiotic stress tolerance enhancement. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cyanobacteria-mediated phenylpropanoids and phytohormones in rice (Oryza sativa) enhance plant growth and stress tolerance.

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Singh, Dhananjaya P; Prabha, Ratna; Yandigeri, Mahesh S; Arora, Dilip K

2011-11-01

Phenylpropanoids, flavonoids and plant growth regulators in rice (Oryza sativa) variety (UPR 1823) inoculated with different cyanobacterial strains namely Anabaena oryzae, Anabaena doliolum, Phormidium fragile, Calothrix geitonos, Hapalosiphon intricatus, Aulosira fertilissima, Tolypothrix tenuis, Oscillatoria acuta and Plectonema boryanum were quantified using HPLC in pot conditions after 15 and 30 days. Qualitative analysis of the induced compounds using reverse phase HPLC and further confirmation with LC-MS/MS showed consistent accumulation of phenolic acids (gallic, gentisic, caffeic, chlorogenic and ferulic acids), flavonoids (rutin and quercetin) and phytohormones (indole acetic acid and indole butyric acid) in rice leaves. Plant growth promotion (shoot, root length and biomass) was positively correlated with total protein and chlorophyll content of leaves. Enzyme activity of peroxidase and phenylalanine ammonia lyase and total phenolic content was fairly high in rice leaves inoculated with O. acuta and P. boryanum after 30 days. Differential systemic accumulation of phenylpropanoids in plant leaves led us to conclude that cyanobacterial inoculation correlates positively with plant growth promotion and stress tolerance in rice. Furthermore, the study helped in deciphering possible mechanisms underlying plant growth promotion and stress tolerance in rice following cyanobacterial inoculation and indicated the less explored avenue of cyanobacterial colonization in stress tolerance against abiotic stress.

Recent advances in the dissection of drought-stress regulatory networks and strategies for development of drought-tolerant transgenic rice plants.

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Todaka, Daisuke; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

2015-01-01

Advances have been made in the development of drought-tolerant transgenic plants, including cereals. Rice, one of the most important cereals, is considered to be a critical target for improving drought tolerance, as present-day rice cultivation requires large quantities of water and as drought-tolerant rice plants should be able to grow in small amounts of water. Numerous transgenic rice plants showing enhanced drought tolerance have been developed to date. Such genetically engineered plants have generally been developed using genes encoding proteins that control drought regulatory networks. These proteins include transcription factors, protein kinases, receptor-like kinases, enzymes related to osmoprotectant or plant hormone synthesis, and other regulatory or functional proteins. Of the drought-tolerant transgenic rice plants described in this review, approximately one-third show decreased plant height under non-stressed conditions or in response to abscisic acid treatment. In cereal crops, plant height is a very important agronomic trait directly affecting yield, although the improvement of lodging resistance should also be taken into consideration. Understanding the regulatory mechanisms of plant growth reduction under drought stress conditions holds promise for developing transgenic plants that produce high yields under drought stress conditions. Plant growth rates are reduced more rapidly than photosynthetic activity under drought conditions, implying that plants actively reduce growth in response to drought stress. In this review, we summarize studies on molecular regulatory networks involved in response to drought stress. In a separate section, we highlight progress in the development of transgenic drought-tolerant rice plants, with special attention paid to field trial investigations.

AtPep3 is a hormone-like peptide that plays a role in the salinity stress tolerance of plants.

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Nakaminami, Kentaro; Okamoto, Masanori; Higuchi-Takeuchi, Mieko; Yoshizumi, Takeshi; Yamaguchi, Yube; Fukao, Yoichiro; Shimizu, Minami; Ohashi, Chihiro; Tanaka, Maho; Matsui, Minami; Shinozaki, Kazuo; Seki, Motoaki; Hanada, Kousuke

2018-05-29

Peptides encoded by small coding genes play an important role in plant development, acting in a similar manner as phytohormones. Few hormone-like peptides, however, have been shown to play a role in abiotic stress tolerance. In the current study, 17 Arabidopsis genes coding for small peptides were found to be up-regulated in response to salinity stress. To identify peptides leading salinity stress tolerance, we generated transgenic Arabidopsis plants overexpressing these small coding genes and assessed survivability and root growth under salinity stress conditions. Results indicated that 4 of the 17 overexpressed genes increased salinity stress tolerance. Further studies focused on AtPROPEP3 , which was the most highly up-regulated gene under salinity stress. Treatment of plants with synthetic peptides encoded by AtPROPEP3 revealed that a C-terminal peptide fragment (AtPep3) inhibited the salt-induced bleaching of chlorophyll in seedlings. Conversely, knockdown AtPROPEP3 transgenic plants exhibited a hypersensitive phenotype under salinity stress, which was complemented by the AtPep3 peptide. This functional AtPep3 peptide region overlaps with an AtPep3 elicitor peptide that is related to the immune response of plants. Functional analyses with a receptor mutant of AtPep3 revealed that AtPep3 was recognized by the PEPR1 receptor and that it functions to increase salinity stress tolerance in plants. Collectively, these data indicate that AtPep3 plays a significant role in both salinity stress tolerance and immune response in Arabidopsis .

Overexpression of CaDSR6 increases tolerance to drought and salt stresses in transgenic Arabidopsis plants.

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Kim, Eun Yu; Seo, Young Sam; Park, Ki Youl; Kim, Soo Jin; Kim, Woo Taek

2014-11-15

The partial CaDSR6 (Capsicum annuum Drought Stress Responsive 6) cDNA was previously identified as a drought-induced gene in hot pepper root tissues. However, the cellular role of CaDSR6 with regard to drought stress tolerance was unknown. In this report, full-length CaDSR6 cDNA was isolated. The deduced CaDSR6 protein was composed of 234 amino acids and contained an approximately 30 amino acid-long Asp-rich domain in its central region. This Asp-rich domain was highly conserved in all plant DSR6 homologs identified and shared a sequence identity with the N-terminal regions of yeast p23(fyp) and human hTCTP, which contain Rab protein binding sites. Transgenic Arabidopsis plants overexpressing CaDSR6 (35S:CaDSR6-sGFP) were tolerant to high salinity, as identified by more vigorous root growth and higher levels of total chlorophyll than wild type plants. CaDSR6-overexpressors were also more tolerant to drought stress compared to wild type plants. The 35S:CaDSR6-sGFP leaves retained their water content and chlorophyll more efficiently than wild type leaves in response to dehydration stress. The expression of drought-induced marker genes, such as RD20, RD22, RD26, RD29A, RD29B, RAB18, KIN2, ABF3, and ABI5, was markedly increased in CaDSR6-overexpressing plants relative to wild type plants under both normal and drought conditions. These results suggest that overexpression of CaDSR6 is associated with increased levels of stress-induced genes, which, in turn, conferred a drought tolerant phenotype in transgenic Arabidopsis plants. Overall, our data suggest that CaDSR6 plays a positive role in the response to drought and salt stresses. Copyright © 2014 Elsevier B.V. All rights reserved.

Transgenic tobacco plants constitutively expressing peanut BTF3 exhibit increased growth and tolerance to abiotic stresses.

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Pruthvi, V; Rama, N; Parvathi, M S; Nataraja, K N

2017-05-01

Abiotic stresses limit crop growth and productivity worldwide. Cellular tolerance, an important abiotic stress adaptive trait, involves coordinated activities of multiple proteins linked to signalling cascades, transcriptional regulation and other diverse processes. Basal transcriptional machinery is considered to be critical for maintaining transcription under stressful conditions. From this context, discovery of novel basal transcription regulators from stress adapted crops like peanut would be useful for improving tolerance of sensitive plant types. In this study, we prospected a basal transcription factor, BTF3 from peanut (Arachis hypogaea L) and studied its relevance in stress acclimation by over expression in tobacco. AhBTF3 was induced under PEG-, NaCl-, and methyl viologen-induced stresses in peanut. The constitutive expression of AhBTF3 in tobacco increased plant growth under non stress condition. The transgenic plants exhibited superior phenotype compared to wild type under mannitol- and NaCl-induced stresses at seedling level. The enhanced cellular tolerance of transgenic plants was evidenced by higher cell membrane stability, reactive oxygen species (ROS) scavenging activity, seedling survival and vigour than wild type. The transgenic lines showed better in vitro regeneration capacity on growth media supplemented with NaCl than wild type. Superior phenotype of transgenic plants under osmotic and salinity stresses seems to be due to constitutive activation of genes of multiple pathways linked to growth and stress adaptation. The study demonstrated that AhBTF3 is a positive regulator of growth and stress acclimation and hence can be considered as a potential candidate gene for crop improvement towards stress adaptation. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Sex-related differences in stress tolerance in dioecious plants: a critical appraisal in a physiological context.

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Juvany, Marta; Munné-Bosch, Sergi

2015-10-01

Sex-related differences in reproductive effort can lead to differences in vegetative growth and stress tolerance. However, do all dioecious plants show sex-related differences in stress tolerance? To what extent can the environmental context and modularity mask sex-related differences in stress tolerance? Finally, to what extent can physiological measurements help us understand secondary sexual dimorphism? This opinion paper aims to answer these three basic questions with special emphasis on developments in research in this area over the last decade. Compelling evidence indicates that dimorphic species do not always show differences in stress tolerance between sexes; and when sex-related differences do occur, they seem to be highly species-specific, with greater stress tolerance in females than males in some species, and the opposite in others. The causes of such sex-related species-specific differences are still poorly understood, and more physiological studies and diversity of plant species that allow comparative analyses are needed. Furthermore, studies performed thus far demonstrate that the expression of dioecy can lead to sex-related differences in physiological traits-from leaf gas exchange to gene expression-but the biological significance of modularity and sectoriality governing such differences has been poorly investigated. Future studies that consider the importance of modularity and sectoriality are essential for unravelling the mechanisms underlying stress adaptation in male and female plants growing in their natural habitat. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

ALA Pretreatment Improves Waterlogging Tolerance of Fig Plants.

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Yuyan An

Full Text Available 5-aminolevulinic acid (ALA, a natural and environmentally friendly plant growth regulator, can improve plant tolerance to various environmental stresses. However, whether ALA can improve plant waterlogging tolerance is unknown. Here, we investigated the effects of ALA pretreatment on the waterlogging-induced damage of fig (Ficus carica Linn. plants, which often suffer from waterlogging stress. ALA pretreatment significantly alleviated stress-induced morphological damage, increased leaf relative water content (RWC, and reduced leaf superoxide anion ([Formula: see text] production rate and malonaldehyde (MDA content in fig leaves, indicating ALA mitigates waterlogging stress of fig plants. We further demonstrated that ALA pretreatment largely promoted leaf chlorophyll content, photosynthetic electron transfer ability, and photosynthetic performance index, indicating ALA significantly improves plant photosynthetic efficiency under waterlogging stress. Moreover, ALA pretreatment significantly increased activities of leaf superoxide dismutase (SOD and peroxidase (POD, root vigor, and activities of root alcohol dehydrogenase (ADH, and lactate dehydrogenase (LDH, indicating ALA also significantly improves antioxidant ability and root function of fig plants under waterlogging stress. Taken together, ALA pretreatment improves waterlogging tolerance of fig plants significantly, and the promoted root respiration, leaf photosynthesis, and antioxidant ability may contribute greatly to this improvement. Our data firstly shows that ALA can improve plant waterlogging tolerance.

Double overexpression of DREB and PIF transcription factors improves drought stress tolerance and cell elongation in transgenic plants.

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Kudo, Madoka; Kidokoro, Satoshi; Yoshida, Takuya; Mizoi, Junya; Todaka, Daisuke; Fernie, Alisdair R; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

2017-04-01

Although a variety of transgenic plants that are tolerant to drought stress have been generated, many of these plants show growth retardation. To improve drought tolerance and plant growth, we applied a gene-stacking approach using two transcription factor genes: DEHYDRATION-RESPONSIVE ELEMENT-BINDING 1A (DREB1A) and rice PHYTOCHROME-INTERACTING FACTOR-LIKE 1 (OsPIL1). The overexpression of DREB1A has been reported to improve drought stress tolerance in various crops, although it also causes a severe dwarf phenotype. OsPIL1 is a rice homologue of Arabidopsis PHYTOCHROME-INTERACTING FACTOR 4 (PIF4), and it enhances cell elongation by activating cell wall-related gene expression. We found that the OsPIL1 protein was more stable than PIF4 under light conditions in Arabidopsis protoplasts. Transactivation analyses revealed that DREB1A and OsPIL1 did not negatively affect each other's transcriptional activities. The transgenic plants overexpressing both OsPIL1 and DREB1A showed the improved drought stress tolerance similar to that of DREB1A overexpressors. Furthermore, double overexpressors showed the enhanced hypocotyl elongation and floral induction compared with the DREB1A overexpressors. Metabolome analyses indicated that compatible solutes, such as sugars and amino acids, accumulated in the double overexpressors, which was similar to the observations of the DREB1A overexpressors. Transcriptome analyses showed an increased expression of abiotic stress-inducible DREB1A downstream genes and cell elongation-related OsPIL1 downstream genes in the double overexpressors, which suggests that these two transcription factors function independently in the transgenic plants despite the trade-offs required to balance plant growth and stress tolerance. Our study provides a basis for plant genetic engineering designed to overcome growth retardation in drought-tolerant transgenic plants. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology

The membrane tethered transcription factor EcbZIP17 from finger millet promotes plant growth and enhances tolerance to abiotic stresses.

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Ramakrishna, Chopperla; Singh, Sonam; Raghavendrarao, Sangala; Padaria, Jasdeep C; Mohanty, Sasmita; Sharma, Tilak Raj; Solanke, Amolkumar U

2018-02-01

The occurrence of various stresses, as the outcome of global climate change, results in the yield losses of crop plants. Prospecting of genes in stress tolerant plant species may help to protect and improve their agronomic performance. Finger millet (Eleusine coracana L.) is a valuable source of superior genes and alleles for stress tolerance. In this study, we isolated a novel endoplasmic reticulum (ER) membrane tethered bZIP transcription factor from finger millet, EcbZIP17. Transgenic tobacco plants overexpressing this gene showed better vegetative growth and seed yield compared with wild type (WT) plants under optimal growth conditions and confirmed upregulation of brassinosteroid signalling genes. Under various abiotic stresses, such as 250 mM NaCl, 10% PEG6000, 400 mM mannitol, water withdrawal, and heat stress, the transgenic plants showed higher germination rate, biomass, primary and secondary root formation, and recovery rate, compared with WT plants. The transgenic plants exposed to an ER stress inducer resulted in greater leaf diameter and plant height as well as higher expression of the ER stress-responsive genes BiP, PDIL, and CRT1. Overall, our results indicated that EcbZIP17 improves plant growth at optimal conditions through brassinosteroid signalling and provide tolerance to various environmental stresses via ER signalling pathways.

Ethylene induced plant stress tolerance by Enterobacter sp. SA187 is mediated by 2-keto-4-methylthiobutyric acid production.

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Axel de Zélicourt

2018-03-01

Full Text Available Several plant species require microbial associations for survival under different biotic and abiotic stresses. In this study, we show that Enterobacter sp. SA187, a desert plant endophytic bacterium, enhances yield of the crop plant alfalfa under field conditions as well as growth of the model plant Arabidopsis thaliana in vitro, revealing a high potential of SA187 as a biological solution for improving crop production. Studying the SA187 interaction with Arabidopsis, we uncovered a number of mechanisms related to the beneficial association of SA187 with plants. SA187 colonizes both the surface and inner tissues of Arabidopsis roots and shoots. SA187 induces salt stress tolerance by production of bacterial 2-keto-4-methylthiobutyric acid (KMBA, known to be converted into ethylene. By transcriptomic, genetic and pharmacological analyses, we show that the ethylene signaling pathway, but not plant ethylene production, is required for KMBA-induced plant salt stress tolerance. These results reveal a novel molecular communication process during the beneficial microbe-induced plant stress tolerance.

EVOLUTIONARY AND ECOLOGICAL ASPECTS OF PLANT STRESS TOLERANCE

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Abdulmalik G. Yusufov

2018-01-01

Full Text Available Abstract. Aim. The aim is to study the threshold sensitivity to salinization of the environment of individual isolated structures for evaluating the salt tolerance of plants. Methods. Comparison of the reaction to salinization of seeds, sprouts, epicotyls, leaves, cotyledons and flowers in species of cultural and natural flora. The following parameters were taken into account in the work: the life span, the time and capacity of for mation of roots and buds, and the wet and dry biomass of species. The results were processed by Statara version 3.0 Shareware (Statistic 5.0 by the parameters of the interaction of roots and shoots. Results. Plant individuals are characterized by the presence of structures that differ in specialization and life span. The question of the correspondence of reactions of structures with the salt tolerance of plants needs to be studied. The stability of the individual as an integral system is determined by the interaction of organs and structures with each other and with other components of the complex community. It evolves in the course of evolution by selecting individuals in the formation of stable plant communities. Quantitative methods of autoecology and genetics of populations are used to understand its mechanisms and role. Conclusion. The structure of an individual plant in an isolated culture is characterized by the specific reaction to salinization of the environment. In this case, the reaction of seeds, sprouts and isolated epicotyls corresponds most closely to the stability of the individual under the stress.

Three cycles of water deficit from seed to young plants of Moringa oleifera woody species improves stress tolerance.

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Rivas, Rebeca; Oliveira, Marciel T; Santos, Mauro G

2013-02-01

The main objective of this study was to assess whether recurring water stress occurring from seed germination to young plants of Moringa oleifera Lam. are able to mitigate the drought stress effects. Germination, gas exchange and biochemical parameters were analysed after three cycles of water deficit. Young plants were used 50 days after germination under three osmotic potentials (0.0, -0.3 and -0.4 MPa). For each germination treatment, control (irrigated) and stressed (10% of water control) plants were compared for a total of six treatments. There were two cycles of drought interspersed with 10 days of rehydration. The young plants of M. oleifera showed increased tolerance to repeated cycles of drought, maintaining high relative water content (RWC), high water use efficiency (WUE), increased photosynthetic pigments and increased activity of antioxidant enzymes. There was rapid recovery of the photosynthetic rate during the rehydration period. The stressed plants from the -0.3 and -0.4 MPa treatments showed higher tolerance compared to the control plants. The results suggest that seeds of M. oleifera subjected to mild water deficit have had increased the ability for drought tolerance when young plant. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

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.

PDH45 overexpressing transgenic tobacco and rice plants provide salinity stress tolerance via less sodium accumulation.

Science.gov (United States)

Nath, Manoj; Garg, Bharti; Sahoo, Ranjan Kumar; Tuteja, Narendra

2015-01-01

Salinity stress negatively affects the crop productivity worldwide, including that of rice. Coping with these losses is a major concern for all countries. The pea DNA helicase, PDH45 is a unique member of helicase family involved in the salinity stress tolerance. However, the exact mechanism of the PDH45 in salinity stress tolerance is yet to be established. Therefore, the present study was conducted to investigate the mechanism of PDH45-mediated salinity stress tolerance in transgenic tobacco and rice lines along with wild type (WT) plants using CoroNa Green dye based sodium localization in root and shoot sections. The results showed that under salinity stress root and shoot of PDH45 overexpressing transgenic tobacco and rice accumulated less sodium (Na(+)) as compared to their respective WT. The present study also reports salinity tolerant (FL478) and salinity susceptible (Pusa-44) varieties of rice accumulated lowest and highest Na(+) level, respectively. All the varieties and transgenic lines of rice accumulate differential Na(+) ions in root and shoot. However, roots accumulate high Na(+) as compared to the shoots in both tobacco and rice transgenic lines suggesting that the Na(+) transport in shoot is somehow inhibited. It is proposed that the PDH45 is probably involved in the deposition of apoplastic hydrophobic barriers and consequently inhibit Na(+) transport to shoot and therefore confers salinity stress tolerance to PDH45 overexpressing transgenic lines. This study concludes that tobacco (dicot) and rice (monocot) transgenic plants probably share common salinity tolerance mechanism mediated by PDH45 gene.

Tolerance of transgenic canola plants (Brassica napus) amended with plant growth-promoting bacteria to flooding stress at a metal-contaminated field site

International Nuclear Information System (INIS)

Farwell, Andrea J.; Vesely, Susanne; Nero, Vincent; Rodriguez, Hilda; McCormack, Kimberley; Shah, Saleh; Dixon, D. George; Glick, Bernard R.

2007-01-01

The growth of transgenic canola (Brassica napus) expressing a gene for the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase was compared to non-transformed canola exposed to flooding and elevated soil Ni concentration, in situ. In addition, the ability of the plant growth-promoting bacterium Pseudomonas putida UW4, which also expresses ACC deaminase, to facilitate the growth of non-transformed and transgenic canola under the above mentioned conditions was examined. Transgenic canola and/or canola treated with P. putida UW4 had greater shoot biomass compared to non-transformed canola under low flood-stress conditions. Under high flood-stress conditions, shoot biomass was reduced and Ni accumulation was increased in all instances relative to low flood-stress conditions. This is the first field study to document the increase in plant tolerance utilizing transgenic plants and plant growth-promoting bacteria exposed to multiple stressors. - Using transgenic plants and plant growth-promoting bacteria as phytoremediation methods increased plant tolerance at a metal-contaminated field site under low flood conditions

Ethylene induced plant stress tolerance by Enterobacter sp. SA187 is mediated by 2‐keto‐4‐methylthiobutyric acid production

KAUST Repository

Zélicourt, Axel de

2018-03-19

Several plant species require microbial associations for survival under different biotic and abiotic stresses. In this study, we show that Enterobacter sp. SA187, a desert plant endophytic bacterium, enhances yield of the crop plant alfalfa under field conditions as well as growth of the model plant Arabidopsis thaliana in vitro, revealing a high potential of SA187 as a biological solution for improving crop production. Studying the SA187 interaction with Arabidopsis, we uncovered a number of mechanisms related to the beneficial association of SA187 with plants. SA187 colonizes both the surface and inner tissues of Arabidopsis roots and shoots. SA187 induces salt stress tolerance by production of bacterial 2-keto-4-methylthiobutyric acid (KMBA), known to be converted into ethylene. By transcriptomic, genetic and pharmacological analyses, we show that the ethylene signaling pathway, but not plant ethylene production, is required for KMBA-induced plant salt stress tolerance. These results reveal a novel molecular communication process during the beneficial microbe-induced plant stress tolerance.

Ethylene induced plant stress tolerance by Enterobacter sp. SA187 is mediated by 2‐keto‐4‐methylthiobutyric acid production

Science.gov (United States)

Xie, Yakun; Rolli, Eleonora; Guerard, Florence; Colcombet, Jean; Benhamed, Moussa; Depaepe, Thomas

2018-01-01

Several plant species require microbial associations for survival under different biotic and abiotic stresses. In this study, we show that Enterobacter sp. SA187, a desert plant endophytic bacterium, enhances yield of the crop plant alfalfa under field conditions as well as growth of the model plant Arabidopsis thaliana in vitro, revealing a high potential of SA187 as a biological solution for improving crop production. Studying the SA187 interaction with Arabidopsis, we uncovered a number of mechanisms related to the beneficial association of SA187 with plants. SA187 colonizes both the surface and inner tissues of Arabidopsis roots and shoots. SA187 induces salt stress tolerance by production of bacterial 2-keto-4-methylthiobutyric acid (KMBA), known to be converted into ethylene. By transcriptomic, genetic and pharmacological analyses, we show that the ethylene signaling pathway, but not plant ethylene production, is required for KMBA-induced plant salt stress tolerance. These results reveal a novel molecular communication process during the beneficial microbe-induced plant stress tolerance. PMID:29554117

Metabolomics as a Tool to Investigate Abiotic Stress Tolerance in Plants

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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.

Acclimation improves salt stress tolerance in Zea mays plants.

Science.gov (United States)

Pandolfi, Camilla; Azzarello, Elisa; Mancuso, Stefano; Shabala, Sergey

2016-08-20

Plants exposure to low level salinity activates an array of processes leading to an improvement of plant stress tolerance. Although the beneficial effect of acclimation was demonstrated in many herbaceous species, underlying mechanisms behind this phenomenon remain poorly understood. In the present study we have addressed this issue by investigating ionic mechanisms underlying the process of plant acclimation to salinity stress in Zea mays. Effect of acclimation were examined in two parallel sets of experiments: a growth experiment for agronomic assessments, sap analysis, stomatal conductance, chlorophyll content, and confocal laser scanning imaging; and a lab experiment for in vivo ion flux measurements from root tissues. Being exposed to salinity, acclimated plants (1) retain more K(+) but accumulate less Na(+) in roots; (2) have better vacuolar Na(+) sequestration ability in leaves and thus are capable of accumulating larger amounts of Na(+) in the shoot without having any detrimental effect on leaf photochemistry; and (3) rely more on Na(+) for osmotic adjustment in the shoot. At the same time, acclimation affect was not related in increased root Na(+) exclusion ability. It appears that even in a such salt-sensitive species as maize, Na(+) exclusion from uptake is of a much less importance compared with the efficient vacuolar Na(+) sequestration in the shoot. Copyright © 2016 Elsevier GmbH. All rights reserved.

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

Enhanced salt stress tolerance in transgenic potato plants expressing IbMYB1, a sweet potato transcription factor.

Science.gov (United States)

Cheng, Yu-Jie; Kim, Myoung-Duck; Deng, Xi-Ping; Kwak, Sang-Soo; Chen, Wei

2013-12-01

IbMYB1, a transcription factor (TF) for R2R3-type MYB TFs, is a key regulator of anthocyanin biosynthesis during storage of sweet potatoes. Anthocyanins provide important antioxidants of nutritional value to humans, and also protect plants from oxidative stress. This study aimed to increase transgenic potatoes' (Solanum tuberosum cv. LongShu No.3) tolerance to environmental stress and enhance their nutritional value. Transgenic potato plants expressing IbMYB1 genes under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter (referred to as SM plants) were successfully generated through Agrobacterium-mediated transformation. Two representative transgenic SM5 and SM12 lines were evaluated for enhanced tolerance to salinity, UV-B rays, and drought conditions. Following treatment of 100 mM NaCl, seedlings of SM5 and SM12 lines showed less root damage and more shoot growth than control lines expressing only an empty vector. Transgenic potato plants in pots treated with 400 mM NaCl showed high amounts of secondary metabolites, including phenols, anthocyanins, and flavonoids, compared with control plants. After treatment of 400 mM NaCl, transgenic potato plants also showed high DDPH radical scavenging activity and high PS II photochemical efficiency compared with the control line. Furthermore, following treatment of NaCl, UV-B, and drought stress, the expression levels of IbMYB1 and several structural genes in the flavonoid biosynthesis such as CHS, DFR, and ANS in transgenic plants were found to be correlated with plant phenotype. The results suggest that enhanced IbMYB1 expression affects secondary metabolism, which leads to improved tolerance ability in transgenic potatoes.

Plant growth promoting bacteria as an alternative strategy for salt tolerance in plants: A review.

Science.gov (United States)

Numan, Muhammad; Bashir, Samina; Khan, Yasmin; Mumtaz, Roqayya; Shinwari, Zabta Khan; Khan, Abdul Latif; Khan, Ajmal; Al-Harrasi, Ahmed

2018-04-01

Approximately 5.2 billion hectare agriculture land are affected by erosion, salinity and soil degradation. Salinity stress has significantly affecting the fertile lands, and therefore possesses a huge impact on the agriculture and economy of a country. Salt stress has severe effects on the growth and development of plants as well as reducing its yield. Plants are inherently equipped with stress tolerance ability to responds the specific type of stress. Plants retained specific mechanisms for salt stress mitigation, such as hormonal stimulation, ion exchange, antioxidant enzymes and activation of signaling cascades on their metabolic and genetic frontiers that sooth the stressed condition. Additional to the plant inherent mechanisms, certain plant growth promoting bacteria (PGPB) also have specialized mechanism that play key role for salt stress tolerance and plant growth promotion. These bacteria triggers plants to produce different plant growth hormones like auxin, cytokinine and gibberellin as well as volatile organic compounds. These bacteria also produces growth regulators like siderophore, which fix nitrogen, solubilize organic and inorganic phosphate. Considering the importance of PGPB in compensation of salt tolerance in plants, the present study has reviewed the different aspect and mechanism of bacteria that play key role in promoting plants growth and yield. It can be concluded that PGPB can be used as a cost effective and economical tool for salinity tolerance and growth promotion in plants. Copyright © 2018 Elsevier GmbH. All rights reserved.

Elucidation of salt stress defense and tolerance mechanisms of crop plants using proteomics--current achievements and perspectives.

Science.gov (United States)

Barkla, Bronwyn J; Castellanos-Cervantes, Thelma; de León, José L Diaz; Matros, Andrea; Mock, Hans-Peter; Perez-Alfocea, Francisco; Salekdeh, Ghasem H; Witzel, Katja; Zörb, Christian

2013-06-01

Salinity is a major threat limiting the productivity of crop plants. A clear demand for improving the salinity tolerance of the major crop plants is imposed by the rapidly growing world population. This review summarizes the achievements of proteomic studies to elucidate the response mechanisms of selected model and crop plants to cope with salinity stress. We also aim at identifying research areas, which deserve increased attention in future proteome studies, as a prerequisite to identify novel targets for breeding strategies. Such areas include the impact of plant-microbial communities on the salinity tolerance of crops under field conditions, the importance of hormone signaling in abiotic stress tolerance, and the significance of control mechanisms underlying the observed changes in the proteome patterns. We briefly highlight the impact of novel tools for future proteome studies and argue for the use of integrated approaches. The evaluation of genetic resources by means of novel automated phenotyping facilities will have a large impact on the application of proteomics especially in combination with metabolomics or transcriptomics. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fine tuning of trehalose biosynthesis and hydrolysis as novel tools for the generation of abiotic stress tolerant plants

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Ines eDelorge

2014-04-01

Full Text Available The impact of abiotic stress on plant growth and development has been and still is a major research topic. An important pathway that has been linked to abiotic stress tolerance is the trehalose biosynthetic pathway. Recent findings showed that trehalose metabolism is also important for normal plant growth and development. The intermediate compound – Trehalose-6-Phosphate (T6P – is now confirmed to act as a sensor for available sucrose, hereby directly influencing the type of response to the changing environmental conditions. This is possible because T6P and/or trehalose or their biosynthetic enzymes are part of complex interaction networks with other crucial hormone and sugar-induced signalling pathways, which may function at different developmental stages. Because of its effect on plant growth and development, modification of trehalose biosynthesis, either at the level of T6P synthesis, T6P hydrolysis or trehalose hydrolysis, has been utilized to try to improve crop yield and biomass. It was shown that alteration of the amounts of either T6P and/or trehalose did result in increased stress tolerance, but also resulted in many unexpected phenotypic alterations. A main challenge is to characterize the part of the signalling pathway resulting in improved stress tolerance, without affecting the pathways resulting in the unwanted phenotypes. One such specific pathway where modification of trehalose metabolism improved stress tolerance, without any side effects, was recently obtained by overexpression of trehalase, which results in a more sensitive reaction of the stomatal guard cells and closing of the stomata under drought stress conditions. We have used the data that have been obtained from different studies to generate the optimal plant that can be constructed based on modifications of trehalose metabolism.

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

Expression of cold and drought regulatory protein (CcCDR) of pigeonpea imparts enhanced tolerance to major abiotic stresses in transgenic rice plants.

Science.gov (United States)

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

2017-06-01

Transgenic rice expressing pigeonpea Cc CDR conferred high-level tolerance to different abiotic stresses. The multiple stress tolerance observed in CcCDR -transgenic lines is attributed to the modulation of ABA-dependent and-independent signalling-pathway genes. Stable transgenic plants expressing Cajanus cajan cold and drought regulatory protein encoding gene (CcCDR), under the control of CaMV35S and rd29A promoters, have been generated in indica rice. Different transgenic lines of CcCDR, when subjected to drought, salt, and cold stresses, exhibited higher seed germination, seedling survival rates, shoot length, root length, and enhanced plant biomass when compared with the untransformed control plants. Furthermore, transgenic plants disclosed higher leaf chlorophyll content, proline, reducing sugars, SOD, and catalase activities, besides lower levels of MDA. Localization studies revealed that the CcCDR-GFP fusion protein was mainly present in the nucleus of transformed cells of rice. The CcCDR transgenics were found hypersensitive to abscisic acid (ABA) and showed reduced seed germination rates as compared to that of control plants. When the transgenic plants were exposed to drought and salt stresses at vegetative and reproductive stages, they revealed larger panicles and higher number of filled grains compared to the untransformed control plants. Under similar stress conditions, the expression levels of P5CS, bZIP, DREB, OsLEA3, and CIPK genes, involved in ABA-dependent and-independent signal transduction pathways, were found higher in the transgenic plants than the control plants. The overall results amply demonstrate that the transgenic rice expressing CcCDR bestows high-level tolerance to drought, salt, and cold stress conditions. Accordingly, the CcCDR might be deployed as a promising candidate gene for improving the multiple stress tolerance of diverse crop plants.

PHYSIOLOGICAL AND BIOCHEMICAL MARKERS OF SALINITY TOLERANCE IN PLANTS

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Mustafa YILDIZ

2011-02-01

Full Text Available Salt stress limits plant productivity in arid and semi arid regions. Salt stress causes decrease in plant growth by adversely affecting physiological processes, especially photosynthesis. Salinity tolerance is defined as the ability of plant to maintain normal rowth and development under salt conditions. Salt stress results in accumulation of low molecular weight compounds, termed compatible solutes, which do not interfere with the normal biochemical reactions. These compatible solutes such as carbohydrates, polyols, amino acids and amides, quaternary ammonium compounds, polyamines andsoluble proteins may play a crucial role in osmotic adjustment, protection of macromolecules, maintenance of cellular pH and detoxification of free radicals. On the other hand, plants subjected to environmental stresses such as salinity produce reactive oxygen species (ROS and these ROS are efficiently eliminated by antioxidant enzyme systems. In plant breeding studies, the use of some physiological and biochemical markers for improving the salt tolerance in plants is crucial. In this review, the possibility of using some physiological and biochemical markers as selection criteria for salt tolerance is discussed.

Suppression of the β-carotene hydroxylase gene increases β-carotene content and tolerance to abiotic stress in transgenic sweetpotato plants.

Science.gov (United States)

Kang, Le; Ji, Chang Yoon; Kim, Sun Ha; Ke, Qingbo; Park, Sung-Chul; Kim, Ho Soo; Lee, Hyeong-Un; Lee, Joon Seol; Park, Woo Sung; Ahn, Mi-Jeong; Lee, Haeng-Soon; Deng, Xiping; Kwak, Sang-Soo

2017-08-01

β-carotene, a carotenoid that plays a key photo-protective role in plants is converted into zeaxanthin by β-carotene hydroxylase (CHY-β). Previous work showed that down-regulation of IbCHY-β by RNA interference (RNAi) results in higher levels of β-carotene and total carotenoids, as well as salt stress tolerance, in cultured transgenic sweetpotato cells. In this study, we introduced the RNAi-IbCHY-β construct into a white-fleshed sweetpotato cultivar (cv. Yulmi) by Agrobacterium-mediated transformation. Among the 13 resultant transgenic sweetpotato plants (referred to as RC plants), three lines were selected for further characterization on the basis of IbCHY-β transcript levels. The RC plants had orange flesh, total carotenoid and β-carotene contents in storage roots were 2-fold and 16-fold higher, respectively, than those of non-transgenic (NT) plants. Unlike storage roots, total carotenoid and β-carotene levels in the leaves of RC plants were slightly increased compared to NT plants. The leaves of RC plants also exhibited tolerance to methyl viologen (MV)-mediated oxidative stress, which was associated with higher 2,2-diphenyl-1- picrylhydrazyl (DPPH) radical-scavenging activity. In addition, RC plants maintained higher levels of chlorophyll and higher photosystem II efficiency than NT plants after 250 mM NaCl stress. Yield of storage roots did not differ significantly between RC and NT plants. These observations suggest that RC plants might be useful as a nutritious and environmental stress-tolerant crop on marginal lands around the world. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The maize WRKY transcription factor ZmWRKY17 negatively regulates salt stress tolerance in transgenic Arabidopsis plants.

Science.gov (United States)

Cai, Ronghao; Dai, Wei; Zhang, Congsheng; Wang, Yan; Wu, Min; Zhao, Yang; Ma, Qing; Xiang, Yan; Cheng, Beijiu

2017-12-01

We cloned and characterized the ZmWRKY17 gene from maize. Overexpression of ZmWRKY17 in Arabidopsis led to increased sensitivity to salt stress and decreased ABA sensitivity through regulating the expression of some ABA- and stress-responsive genes. The WRKY transcription factors have been reported to function as positive or negative regulators in many different biological processes including plant development, defense regulation and stress response. This study isolated a maize WRKY gene, ZmWRKY17, and characterized its role in tolerance to salt stress by generating transgenic Arabidopsis plants. Expression of the ZmWRKY17 was up-regulated by drought, salt and abscisic acid (ABA) treatments. ZmWRKY17 was localized in the nucleus with no transcriptional activation in yeast. Yeast one-hybrid assay showed that ZmWRKY17 can specifically bind to W-box, and it can activate W-box-dependent transcription in planta. Heterologous overexpression of ZmWRKY17 in Arabidopsis remarkably reduced plant tolerance to salt stress, as determined through physiological analyses of the cotyledons greening rate, root growth, relative electrical leakage and malondialdehyde content. Additionally, ZmWRKY17 transgenic plants showed decreased sensitivity to ABA during seed germination and early seedling growth. Transgenic plants accumulated higher content of ABA than wild-type (WT) plants under NaCl condition. Transcriptome and quantitative real-time PCR analyses revealed that some stress-related genes in transgenic seedlings showed lower expression level than that in the WT when treated with NaCl. Taken together, these results suggest that ZmWRKY17 may act as a negative regulator involved in the salt stress responses through ABA signalling.

Wheat F-Box Protein Gene TaFBA1 Is Involved in Plant Tolerance to Heat Stress

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Qinxue Li

2018-04-01

Full Text Available Adverse environmental conditions, including high temperature, often affect the growth and production of crops worldwide. F-box protein, a core component of the Skp1-Cullin-F-box (SCF E3 ligase complex, plays an important role in abiotic stress responses. A previously cloned gene from wheat, TaFBA1, encodes a homologous F-box protein. A Yeast two-Hybrid (Y2H assay showed that TaFBA1 interacted with other SCF proteins. We found that the expression of TaFBA1 could be induced by heat stress (45°C. Overexpression of TaFBA1 enhanced heat stress tolerance in transgenic tobacco, because growth inhibition was reduced and photosynthesis increased as compared with those in the wild type (WT plants. Furthermore, the accumulation of H2O2, O2-, and carbonyl protein decreased and cell damage was alleviated in transgenic plants under heat stress, which resulted in less oxidative damage. However, the transgenic plants contained more enzymatic antioxidants after heat stress, which might be related to the regulation of some antioxidant gene expressions. The qRT-PCR analysis showed that the overexpression of TaFBA1 upregulated the expression of genes involved in reactive oxygen species (ROS scavenging, proline biosynthesis, and abiotic stress responses. We identified the interaction of TaFBA1 with Triticum aestivum stress responsive protein 1 (TaASRP1 by Y2H assay and bimolecular fluorescence complementation (BiFC assay. The results suggested that TaFBA1 may improve enzymatic antioxidant levels and regulate gene expression by interacting with other proteins, such as TaASRP1, which leads to the enhanced heat stress tolerance seen in the transgenic plants.

Potato Annexin STANN1 Promotes Drought Tolerance and Mitigates Light Stress in Transgenic Solanum tuberosum L. Plants

Science.gov (United States)

Szalonek, Michal; Sierpien, Barbara; Rymaszewski, Wojciech; Gieczewska, Katarzyna; Garstka, Maciej; Lichocka, Malgorzata; Sass, Laszlo; Paul, Kenny; Vass, Imre; Vankova, Radomira; Dobrev, Peter; Szczesny, Pawel; Marczewski, Waldemar; Krusiewicz, Dominika; Strzelczyk-Zyta, Danuta; Hennig, Jacek; Konopka-Postupolska, Dorota

2015-01-01

Annexins are a family of calcium- and membrane-binding proteins that are important for plant tolerance to adverse environmental conditions. Annexins function to counteract oxidative stress, maintain cell redox homeostasis, and enhance drought tolerance. In the present study, an endogenous annexin, STANN1, was overexpressed to determine whether crop yields could be improved in potato (Solanum tuberosum L.) during drought. Nine potential potato annexins were identified and their expression characterized in response to drought treatment. STANN1 mRNA was constitutively expressed at a high level and drought treatment strongly increased transcription levels. Therefore, STANN1 was selected for overexpression analysis. Under drought conditions, transgenic potato plants ectopically expressing STANN1 were more tolerant to water deficit in the root zone, preserved more water in green tissues, maintained chloroplast functions, and had higher accumulation of chlorophyll b and xanthophylls (especially zeaxanthin) than wild type (WT). Drought-induced reductions in the maximum efficiency and the electron transport rate of photosystem II (PSII), as well as the quantum yield of photosynthesis, were less pronounced in transgenic plants overexpressing STANN1 than in the WT. This conferred more efficient non-photochemical energy dissipation in the outer antennae of PSII and probably more efficient protection of reaction centers against photooxidative damage in transgenic plants under drought conditions. Consequently, these plants were able to maintain effective photosynthesis during drought, which resulted in greater productivity than WT plants despite water scarcity. Although the mechanisms underlying this stress protection are not yet clear, annexin-mediated photoprotection is probably linked to protection against light-induced oxidative stress. PMID:26172952

Potato Annexin STANN1 Promotes Drought Tolerance and Mitigates Light Stress in Transgenic Solanum tuberosum L. Plants.

Science.gov (United States)

Szalonek, Michal; Sierpien, Barbara; Rymaszewski, Wojciech; Gieczewska, Katarzyna; Garstka, Maciej; Lichocka, Malgorzata; Sass, Laszlo; Paul, Kenny; Vass, Imre; Vankova, Radomira; Dobrev, Peter; Szczesny, Pawel; Marczewski, Waldemar; Krusiewicz, Dominika; Strzelczyk-Zyta, Danuta; Hennig, Jacek; Konopka-Postupolska, Dorota

2015-01-01

Annexins are a family of calcium- and membrane-binding proteins that are important for plant tolerance to adverse environmental conditions. Annexins function to counteract oxidative stress, maintain cell redox homeostasis, and enhance drought tolerance. In the present study, an endogenous annexin, STANN1, was overexpressed to determine whether crop yields could be improved in potato (Solanum tuberosum L.) during drought. Nine potential potato annexins were identified and their expression characterized in response to drought treatment. STANN1 mRNA was constitutively expressed at a high level and drought treatment strongly increased transcription levels. Therefore, STANN1 was selected for overexpression analysis. Under drought conditions, transgenic potato plants ectopically expressing STANN1 were more tolerant to water deficit in the root zone, preserved more water in green tissues, maintained chloroplast functions, and had higher accumulation of chlorophyll b and xanthophylls (especially zeaxanthin) than wild type (WT). Drought-induced reductions in the maximum efficiency and the electron transport rate of photosystem II (PSII), as well as the quantum yield of photosynthesis, were less pronounced in transgenic plants overexpressing STANN1 than in the WT. This conferred more efficient non-photochemical energy dissipation in the outer antennae of PSII and probably more efficient protection of reaction centers against photooxidative damage in transgenic plants under drought conditions. Consequently, these plants were able to maintain effective photosynthesis during drought, which resulted in greater productivity than WT plants despite water scarcity. Although the mechanisms underlying this stress protection are not yet clear, annexin-mediated photoprotection is probably linked to protection against light-induced oxidative stress.

Potato Annexin STANN1 Promotes Drought Tolerance and Mitigates Light Stress in Transgenic Solanum tuberosum L. Plants.

Directory of Open Access Journals (Sweden)

Michal Szalonek

Full Text Available Annexins are a family of calcium- and membrane-binding proteins that are important for plant tolerance to adverse environmental conditions. Annexins function to counteract oxidative stress, maintain cell redox homeostasis, and enhance drought tolerance. In the present study, an endogenous annexin, STANN1, was overexpressed to determine whether crop yields could be improved in potato (Solanum tuberosum L. during drought. Nine potential potato annexins were identified and their expression characterized in response to drought treatment. STANN1 mRNA was constitutively expressed at a high level and drought treatment strongly increased transcription levels. Therefore, STANN1 was selected for overexpression analysis. Under drought conditions, transgenic potato plants ectopically expressing STANN1 were more tolerant to water deficit in the root zone, preserved more water in green tissues, maintained chloroplast functions, and had higher accumulation of chlorophyll b and xanthophylls (especially zeaxanthin than wild type (WT. Drought-induced reductions in the maximum efficiency and the electron transport rate of photosystem II (PSII, as well as the quantum yield of photosynthesis, were less pronounced in transgenic plants overexpressing STANN1 than in the WT. This conferred more efficient non-photochemical energy dissipation in the outer antennae of PSII and probably more efficient protection of reaction centers against photooxidative damage in transgenic plants under drought conditions. Consequently, these plants were able to maintain effective photosynthesis during drought, which resulted in greater productivity than WT plants despite water scarcity. Although the mechanisms underlying this stress protection are not yet clear, annexin-mediated photoprotection is probably linked to protection against light-induced oxidative stress.

Overexpression of the PtSOS2 gene improves tolerance to salt stress in transgenic poplar plants.

Science.gov (United States)

Yang, Yang; Tang, Ren-Jie; Jiang, Chun-Mei; Li, Bei; Kang, Tao; Liu, Hua; Zhao, Nan; Ma, Xu-Jun; Yang, Lei; Chen, Shao-Liang; Zhang, Hong-Xia

2015-09-01

In higher plants, the salt overly sensitive (SOS) signalling pathway plays a crucial role in maintaining ion homoeostasis and conferring salt tolerance under salinity condition. Previously, we functionally characterized the conserved SOS pathway in the woody plant Populus trichocarpa. In this study, we demonstrate that overexpression of the constitutively active form of PtSOS2 (PtSOS2TD), one of the key components of this pathway, significantly increased salt tolerance in aspen hybrid clone Shanxin Yang (Populus davidiana × Populus bolleana). Compared to the wild-type control, transgenic plants constitutively expressing PtSOS2TD exhibited more vigorous growth and produced greater biomass in the presence of high concentrations of NaCl. The improved salt tolerance was associated with a decreased Na(+) accumulation in the leaves of transgenic plants. Further analyses revealed that plasma membrane Na(+) /H(+) exchange activity and Na(+) efflux in transgenic plants were significantly higher than those in the wild-type plants. Moreover, transgenic plants showed improved capacity in scavenging reactive oxygen species (ROS) generated by salt stress. Taken together, our results suggest that PtSOS2 could serve as an ideal target gene to genetically engineer salt-tolerant trees. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Polyamines Function in Stress Tolerance: From Synthesis to Regulation

Directory of Open Access Journals (Sweden)

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.

A Novel Non-coding RNA Regulates Drought Stress Tolerance in Arabidopsis thaliana

KAUST Repository

Albesher, Nour H.

2014-05-01

Drought (soil water deficit) as a major adverse environmental condition can result in serious reduction in plant growth and crop production. Plants respond and adapt to drought stresses by triggering various signalling pathways leading to physiological, metabolic and developmental changes that may ultimately contribute to enhanced tolerance to the stress. Here, a novel non-coding RNA (ncRNA) involved in plant drought stress tolerance was identified. We showed that increasing the expression of this ncRNA led to enhanced sensitivity during seed germination and seedling growth to the phytohormone abscisic acid. The mutant seedlings are also more sensitive to osmotic stress inhibition of lateral root growth. Consistently, seedlings with enhanced expression of this ncRNA exhibited reduced transiprational water loss and were more drought-tolerant than the wild type. Future analyses of the mechanism for its role in drought tolerance may help us to understand how plant drought tolerance could be further regulated by this novel ncRNA.

Stress-inducible expression of an F-box gene TaFBA1 from wheat enhanced the drought tolerance in transgenic tobacco plants without impacting growth and development

Directory of Open Access Journals (Sweden)

Xiangzhu Kong

2016-09-01

Full Text Available E3 ligase plays an important role in the response to many environment stresses in plants. In our previous study, constitutive overexpression of an F-box protein gene TaFBA1 driven by 35S promoter improved the drought tolerance in transgenic tobacco plants, but the growth and development in transgenic plants was altered in normal conditions. In this study, we used stress-inducible promoter RD29A instead of 35S promoter, as a results, the stress-inducible transgenic tobacco plants exhibit a similar phenotype with WT plants. However, the drought tolerance of the transgenic plants with stress-inducible expressed TaFBA1 was enhanced. The improved drought tolerance of transgenic plants was indicated by their higher seed germination rate and survival rate, greater biomass and photosynthesis than those of WT under water stress, which may be related to their greater water retention capability and osmotic adjustment. Moreover, the transgenic plants accumulated less reactive oxygen species (ROS, kept lower MDA content and membrane leakage under water stress, which may be related to their higher levels of antioxidant enzyme activity and upregulated gene expression of some antioxidant enzymes. These results suggest that stress induced expression of TaFBA1 confers drought tolerance via the improved water retention and antioxidative compete abilibty. Meanwhile, this stress-inducible expression strategy by RD29A promoter can minimize the unexpectable effects by 35S constitutive promoter on phenotypes of the transgenic plants.

Stress-Inducible Expression of an F-box Gene TaFBA1 from Wheat Enhanced the Drought Tolerance in Transgenic Tobacco Plants without Impacting Growth and Development.

Science.gov (United States)

Kong, Xiangzhu; Zhou, Shumei; Yin, Suhong; Zhao, Zhongxian; Han, Yangyang; Wang, Wei

2016-01-01

E3 ligase plays an important role in the response to many environment stresses in plants. In our previous study, constitutive overexpression of an F-box protein gene TaFBA1 driven by 35S promoter improved the drought tolerance in transgenic tobacco plants, but the growth and development in transgenic plants was altered in normal conditions. In this study, we used stress-inducible promoter RD29A instead of 35S promoter, as a results, the stress-inducible transgenic tobacco plants exhibit a similar phenotype with wild type (WT) plants. However, the drought tolerance of the transgenic plants with stress-inducible expressed TaFBA1 was enhanced. The improved drought tolerance of transgenic plants was indicated by their higher seed germination rate and survival rate, greater biomass and photosynthesis than those of WT under water stress, which may be related to their greater water retention capability and osmotic adjustment. Moreover, the transgenic plants accumulated less reactive oxygen species, kept lower MDA content and membrane leakage under water stress, which may be related to their higher levels of antioxidant enzyme activity and upregulated gene expression of some antioxidant enzymes. These results suggest that stress induced expression of TaFBA1 confers drought tolerance via the improved water retention and antioxidative compete ability. Meanwhile, this stress-inducible expression strategy by RD29A promoter can minimize the unexpectable effects by 35S constitutive promoter on phenotypes of the transgenic plants.

Enhancing water stress tolerance improves fitness in biological control strains of Lactobacillus plantarum in plant environments.

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Daranas, Núria; Badosa, Esther; Francés, Jesús; Montesinos, Emilio; Bonaterra, Anna

2018-01-01

Lactobacillus plantarum strains PM411 and TC92 can efficiently control bacterial plant diseases, but their fitness on the plant surface is limited under unfavourable low relative humidity (RH) conditions. To increase tolerance of these strains to water stress, an adaptive strategy was used consisting of hyperosmotic and acidic conditions during growth. Adapted cells had higher survival rates under desiccation than non-adapted cells. Transcript levels and patterns of general stress-related genes increased immediately after the combined-stress adaptation treatment, and remained unaltered or repressed during the desiccation challenge. However, there were differences between strains in the transcription patterns that were in agreement with a better performance of adapted cells of PM411 than TC92 in plant surfaces under low RH environmental conditions. The combined-stress adaptation treatment increased the survival of PM411 cells consistently in different plant hosts in the greenhouse and under field conditions. Stress-adapted cells of PM411 had similar biocontrol potential against bacterial plant pathogens than non-adapted cells, but with less variability within experiments.

Enhancing water stress tolerance improves fitness in biological control strains of Lactobacillus plantarum in plant environments.

Directory of Open Access Journals (Sweden)

Núria Daranas

Full Text Available Lactobacillus plantarum strains PM411 and TC92 can efficiently control bacterial plant diseases, but their fitness on the plant surface is limited under unfavourable low relative humidity (RH conditions. To increase tolerance of these strains to water stress, an adaptive strategy was used consisting of hyperosmotic and acidic conditions during growth. Adapted cells had higher survival rates under desiccation than non-adapted cells. Transcript levels and patterns of general stress-related genes increased immediately after the combined-stress adaptation treatment, and remained unaltered or repressed during the desiccation challenge. However, there were differences between strains in the transcription patterns that were in agreement with a better performance of adapted cells of PM411 than TC92 in plant surfaces under low RH environmental conditions. The combined-stress adaptation treatment increased the survival of PM411 cells consistently in different plant hosts in the greenhouse and under field conditions. Stress-adapted cells of PM411 had similar biocontrol potential against bacterial plant pathogens than non-adapted cells, but with less variability within experiments.

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

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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. Copyright © 2016 Elsevier GmbH. All rights reserved.

Approaches in modulating proline metabolism in plants for salt and drought stress tolerance: Phytohormones, mineral nutrients and transgenics.

Science.gov (United States)

Per, Tasir S; Khan, Nafees A; Reddy, Palakolanu Sudhakar; Masood, Asim; Hasanuzzaman, Mirza; Khan, M Iqbal R; Anjum, Naser A

2017-06-01

Major abiotic stress factors such as salt and drought adversely affect important physiological processes and biochemical mechanisms and cause severe loss in crop productivity worldwide. Plants develop various strategies to stand healthy against these stress factors. The accumulation of proline (Pro) is one of the striking metabolic responses of plants to salt and drought stress. Pro biosynthesis and signalling contribute to the redox balance of cell under normal and stressful conditions. However, literature is meager on the sustainable strategies potentially fit for modulating Pro biosynthesis and production in stressed plants. Considering the recent literature, this paper in its first part overviews Pro biosynthesis and transport in plants and also briefly highlights the significance of Pro in plant responses to salt and drought stress. Secondly, this paper discusses mechanisms underlying the regulation of Pro metabolism in salt and drought-exposed plant via phytohormones, mineral nutrients and transgenic approaches. The outcome of the studies may give new opportunities in modulating Pro metabolism for improving plant tolerance to salt and drought stress and benefit sustainable agriculture. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Genetically engineered Rice with transcription factor DREB genes for abiotic stress tolerance(abstract)

International Nuclear Information System (INIS)

Datta, S.K.; Datta, K.

2005-01-01

Water stress (drought and Salinity) is the most severe limitation to rice productivity. Several breeding approaches (MAS, QTL) applied to suitable genotypes are in place at IRRI and elsewhere. Phenotyping of water stress tolerance is in progress with potential predictability. Dr. Shinozaki's group has cloned a number of transcription factor genes, which have been shown to work in Arabidopsis to achieve drought, cold, and salinity tolerant plants. None of these genes have as yet displayed their potential functioning in rice. Genetic engineering aims at cross talk between different stress signaling pathways leading to stress tolerance. Osmotic Adjustment (OA) is an effective component of abiotic stress (drought and salinity) tolerance in many plants including rice. When plant experiences water stress, OA contributes to turgor maintenance of both shoots and roots. Conventional breeding could not achieve the OA in rice excepting a few rice cultivars, which are partially adapted to water-stress conditions. Several stress-related genes have now been cloned and transferred in to enhance the osmolytes and some transgenic lines showed increased tolerance to osmotic stress. A few strategies could be effectively deployed for a better understanding of water-stress tolerance in rice and to develop transgenic rice, which can survive for a critical period of water-stress conditions: 1) Switching on of transcription factor regulating the expression of several genes related to abiotic stress, 2) Use of a suitable stress inducible promoter driving the target gene for an efficient and directed expression in plants, 3) Understanding of phenotyping and GxE in a given environment, 4) Selection of a few adaptive rice cultivars suitable in drought/salinity prone areas, 5) Microarray, proteomics, QTL and MAS may expedite the cloning and characterizing the stress induced genes, and 6) Finally, the efficient transformation system for generating a large number of transgenic rice of different

Overexpression of persimmon DkXTH1 enhanced tolerance to abiotic stress and delayed fruit softening in transgenic plants.

Science.gov (United States)

Han, Ye; Han, Shoukun; Ban, Qiuyan; He, Yiheng; Jin, Mijing; Rao, Jingping

2017-04-01

DkXTH1 promoted cell elongation and more strength to maintain structural integrity by involving in cell wall assembly, thus enhanced tolerance to abiotic stress with broader phenotype in transgenic plants. Xyloglucan endotransglucosylase/hydrolase (XTH) is thought to play a key role in cell wall modifications by cleaving and re-joining xyloglucan, and participates in the diverse physiological processes. DkXTH1 was found to peak in immature expanding persimmon fruit, and its higher expression level exhibited along with firmer fruit during storage. In the present study, transgenic Arabidopsis and tomato plants were generated with DkXTH1 constitutively expressed. Overexpression of DkXTH1 enhanced tolerance to salt, ABA and drought stresses in transgenic Arabidopsis plants with respect to root and leaf growth, and survival. Transgenic tomatoes collected at the mature green stage, presented delayed fruit softening coupled with postponed color change, a later and lower ethylene peak, and higher firmness in comparison with the wild-type tomatoes during storage. Furthermore, broader leaves and tomato fruit with larger diameter were gained in transgenic Arabidopsis and tomato, respectively. Most importantly, transgenic plants exhibited more large and irregular cells with higher density of cell wall and intercellular spaces, resulting from the overactivity of XET enzymes involving in cell wall assembly. We suggest that DkXTH1 expression resulted in cells with more strength and thickness to maintain structural integrity, and thus enhanced tolerance to abiotic stress and delayed fruit softening in transgenic plants.

Toxicity and tolerance of aluminum in plants: tailoring plants to suit to acid soils.

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Sade, Hemalatha; Meriga, Balaji; Surapu, Varalakshmi; Gadi, Jogeswar; Sunita, M S L; Suravajhala, Prashanth; Kavi Kishor, P B

2016-04-01

Aluminum (Al) stress is one of the serious limiting factors in plant productivity in acidic soils, which constitute about 50 % of the world's potentially arable lands and causes anywhere between 25 and 80 % of yield losses depending upon the species. The mechanism of Al toxicity and tolerance has been examined in plants, which is vital for crop improvement and enhanced food production in the future. Two mechanisms that facilitate Al tolerance in plants are Al exclusion from the roots and the ability to tolerate Al in the symplast or both. Although efforts have been made to unravel Al-resistant factors, many aspects remain unclear. Certain gene families such as MATE, ALMT, ASR, and ABC transporters have been implicated in some plants for resistance to Al which would enhance the opportunities for creating crop plants suitable to grow in acidic soils. Though QTLs have been identified related to Al-tolerance, no crop plant that is tolerant to Al has been evolved so far using breeding or molecular approaches. The remarkable changes that plants experience at the physiological, biochemical and molecular level under Al stress, the vast array of genes involved in Al toxicity-tolerance, the underlying signaling events and the holistic image of the molecular regulation, and the possibility of creating transgenics for Al tolerance are discussed in this review.

Effects, tolerance mechanisms and management of salt stress in grain legumes.

Science.gov (United States)

Farooq, Muhammad; Gogoi, Nirmali; Hussain, Mubshar; Barthakur, Sharmistha; Paul, Sreyashi; Bharadwaj, Nandita; Migdadi, Hussein M; Alghamdi, Salem S; Siddique, Kadambot H M

2017-09-01

Salt stress is an ever-present threat to crop yields, especially in countries with irrigated agriculture. Efforts to improve salt tolerance in crop plants are vital for sustainable crop production on marginal lands to ensure future food supplies. Grain legumes are a fascinating group of plants due to their high grain protein contents and ability to fix biological nitrogen. However, the accumulation of excessive salts in soil and the use of saline groundwater are threatening legume production worldwide. Salt stress disturbs photosynthesis and hormonal regulation and causes nutritional imbalance, specific ion toxicity and osmotic effects in legumes to reduce grain yield and quality. Understanding the responses of grain legumes to salt stress and the associated tolerance mechanisms, as well as assessing management options, may help in the development of strategies to improve the performance of grain legumes under salt stress. In this manuscript, we discuss the effects, tolerance mechanisms and management of salt stress in grain legumes. The principal inferences of the review are: (i) salt stress reduces seed germination (by up to more than 50%) either by inhibiting water uptake and/or the toxic effect of ions in the embryo, (ii) salt stress reduces growth (by more than 70%), mineral uptake, and yield (by 12-100%) due to ion toxicity and reduced photosynthesis, (iii) apoplastic acidification is a good indicator of salt stress tolerance, (iv) tolerance to salt stress in grain legumes may develop through excretion and/or compartmentalization of toxic ions, increased antioxidant capacity, accumulation of compatible osmolytes, and/or hormonal regulation, (v) seed priming and nutrient management may improve salt tolerance in grain legumes, (vi) plant growth promoting rhizobacteria and arbuscular mycorrhizal fungi may help to improve salt tolerance due to better plant nutrient availability, and (vii) the integration of screening, innovative breeding, and the development of

Bacillus amyloliquefaciens Confers Tolerance to Various Abiotic Stresses and Modulates Plant Response to Phytohormones through Osmoprotection and Gene Expression Regulation in Rice

Directory of Open Access Journals (Sweden)

Shalini Tiwari

2017-08-01

Full Text Available Being sessile in nature, plants have to withstand various adverse environmental stress conditions including both biotic and abiotic stresses. Comparatively, abiotic stresses such as drought, salinity, high temperature, and cold pose major threat to agriculture by negatively impacting plant growth and yield worldwide. Rice is one of the most widely consumed staple cereals across the globe, the production and productivity of which is also severely affected by different abiotic stresses. Therefore, several crop improvement programs are directed toward developing stress tolerant rice cultivars either through marker assisted breeding or transgenic technology. Alternatively, some known rhizospheric competent bacteria are also known to improve plant growth during abiotic stresses. A plant growth promoting rhizobacteria (PGPR, Bacillus amyloliquefaciens NBRI-SN13 (SN13 was previously reported by our lab to confer salt stress tolerance to rice seedlings. However, the present study investigates the role of SN13 in ameliorating various abiotic stresses such as salt, drought, desiccation, heat, cold, and freezing on a popular rice cv. Saryu-52 under hydroponic growth conditions. Apart from this, seedlings were also exogenously supplied with abscisic acid (ABA, salicylic acid (SA, jasmonic acid (JA and ethephon (ET to study the role of SN13 in phytohormone-induced stress tolerance as well as its role in abiotic and biotic stress cross-talk. All abiotic stresses and phytohormone treatments significantly affected various physiological and biochemical parameters like membrane integrity and osmolyte accumulation. SN13 also positively modulated stress-responsive gene expressions under various abiotic stresses and phytohormone treatments suggesting its multifaceted role in cross-talk among stresses and phytohormones in response to PGPR. To the best of our knowledge, this is the first report on detailed analysis of plant growth promotion and stress alleviation by a

Halophytes: Potential Resources for Salt Stress Tolerance Genes and Promoters.

Science.gov (United States)

Mishra, Avinash; Tanna, Bhakti

2017-01-01

Halophytes have demonstrated their capability to thrive under extremely saline conditions and thus considered as one of the best germplasm for saline agriculture. Salinity is a worldwide problem, and the salt-affected areas are increasing day-by-day because of scanty rainfall, poor irrigation system, salt ingression, water contamination, and other environmental factors. The salinity stress tolerance mechanism is a very complex phenomenon, and some pathways are coordinately linked for imparting salinity tolerance. Though a number of salt responsive genes have been reported from the halophytes, there is always a quest for promising stress-responsive genes that can modulate plant physiology according to the salt stress. Halophytes such as Aeluropus, Mesembryanthemum, Suaeda, Atriplex, Thellungiella, Cakile , and Salicornia serve as a potential candidate for the salt-responsive genes and promoters. Several known genes like antiporters ( NHX, SOS, HKT, VTPase ), ion channels (Cl - , Ca 2+ , aquaporins), antioxidant encoding genes ( APX, CAT, GST, BADH, SOD ) and some novel genes such as USP, SDR1, SRP etc. were isolated from halophytes and explored for developing stress tolerance in the crop plants (glycophytes). It is evidenced that stress triggers salt sensors that lead to the activation of stress tolerance mechanisms which involve multiple signaling proteins, up- or down-regulation of several genes, and finally the distinctive or collective effects of stress-responsive genes. In this review, halophytes are discussed as an excellent platform for salt responsive genes which can be utilized for developing salinity tolerance in crop plants through genetic engineering.

Generating high temperature tolerant transgenic plants: Achievements and challenges.

Science.gov (United States)

Grover, Anil; Mittal, Dheeraj; Negi, Manisha; Lavania, Dhruv

2013-05-01

Production of plants tolerant to high temperature stress is of immense significance in the light of global warming and climate change. Plant cells respond to high temperature stress by re-programming their genetic machinery for survival and reproduction. High temperature tolerance in transgenic plants has largely been achieved either by over-expressing heat shock protein genes or by altering levels of heat shock factors that regulate expression of heat shock and non-heat shock genes. Apart from heat shock factors, over-expression of other trans-acting factors like DREB2A, bZIP28 and WRKY proteins has proven useful in imparting high temperature tolerance. Besides these, elevating the genetic levels of proteins involved in osmotic adjustment, reactive oxygen species removal, saturation of membrane-associated lipids, photosynthetic reactions, production of polyamines and protein biosynthesis process have yielded positive results in equipping transgenic plants with high temperature tolerance. Cyclic nucleotide gated calcium channel proteins that regulate calcium influxes across the cell membrane have recently been shown to be the key players in induction of high temperature tolerance. The involvement of calmodulins and kinases in activation of heat shock factors has been implicated as an important event in governing high temperature tolerance. Unfilled gaps limiting the production of high temperature tolerant transgenic plants for field level cultivation are discussed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Predicting coexistence of plants subject to a tolerance-competition trade-off.

Science.gov (United States)

Haegeman, Bart; Sari, Tewfik; Etienne, Rampal S

2014-06-01

Ecological trade-offs between species are often invoked to explain species coexistence in ecological communities. However, few mathematical models have been proposed for which coexistence conditions can be characterized explicitly in terms of a trade-off. Here we present a model of a plant community which allows such a characterization. In the model plant species compete for sites where each site has a fixed stress condition. Species differ both in stress tolerance and competitive ability. Stress tolerance is quantified as the fraction of sites with stress conditions low enough to allow establishment. Competitive ability is quantified as the propensity to win the competition for empty sites. We derive the deterministic, discrete-time dynamical system for the species abundances. We prove the conditions under which plant species can coexist in a stable equilibrium. We show that the coexistence conditions can be characterized graphically, clearly illustrating the trade-off between stress tolerance and competitive ability. We compare our model with a recently proposed, continuous-time dynamical system for a tolerance-fecundity trade-off in plant communities, and we show that this model is a special case of the continuous-time version of our model.

Halophytes: Potential Resources for Salt Stress Tolerance Genes and Promoters

Directory of Open Access Journals (Sweden)

Avinash Mishra

2017-05-01

Full Text Available Halophytes have demonstrated their capability to thrive under extremely saline conditions and thus considered as one of the best germplasm for saline agriculture. Salinity is a worldwide problem, and the salt-affected areas are increasing day-by-day because of scanty rainfall, poor irrigation system, salt ingression, water contamination, and other environmental factors. The salinity stress tolerance mechanism is a very complex phenomenon, and some pathways are coordinately linked for imparting salinity tolerance. Though a number of salt responsive genes have been reported from the halophytes, there is always a quest for promising stress-responsive genes that can modulate plant physiology according to the salt stress. Halophytes such as Aeluropus, Mesembryanthemum, Suaeda, Atriplex, Thellungiella, Cakile, and Salicornia serve as a potential candidate for the salt-responsive genes and promoters. Several known genes like antiporters (NHX, SOS, HKT, VTPase, ion channels (Cl−, Ca2+, aquaporins, antioxidant encoding genes (APX, CAT, GST, BADH, SOD and some novel genes such as USP, SDR1, SRP etc. were isolated from halophytes and explored for developing stress tolerance in the crop plants (glycophytes. It is evidenced that stress triggers salt sensors that lead to the activation of stress tolerance mechanisms which involve multiple signaling proteins, up- or down-regulation of several genes, and finally the distinctive or collective effects of stress-responsive genes. In this review, halophytes are discussed as an excellent platform for salt responsive genes which can be utilized for developing salinity tolerance in crop plants through genetic engineering.

SALT TOLERANCE OF CROP PLANTS

OpenAIRE

Hamdia, M. A; Shaddad, M. A. K.

2010-01-01

Several environmental factors adversely affect plant growth and development and final yield performance of a crop. Drought, salinity, nutrient imbalances (including mineral toxicities and deficiencies) and extremes of temperature are among the major environmental constraints to crop productivity worldwide. Development of crop plants with stress tolerance, however, requires, among others, knowledge of the physiological mechanisms and genetic controls of the contributing traits at different pla...

A cellulose synthase-like protein is required for osmotic stress tolerance in Arabidopsis

KAUST Repository

Zhu, Jianhua

2010-04-16

Osmotic stress imposed by soil salinity and drought stress significantly affects plant growth and development, but osmotic stress sensing and tolerance mechanisms are not well understood. Forward genetic screens using a root-bending assay have previously identified salt overly sensitive (sos) mutants of Arabidopsis that fall into five loci, SOS1 to SOS5. These loci are required for the regulation of ion homeostasis or cell expansion under salt stress, but do not play a major role in plant tolerance to the osmotic stress component of soil salinity or drought. Here we report an additional sos mutant, sos6-1, which defines a locus essential for osmotic stress tolerance. sos6-1 plants are hypersensitive to salt stress and osmotic stress imposed by mannitol or polyethylene glycol in culture media or by water deficit in the soil. SOS6 encodes a cellulose synthase-like protein, AtCSLD5. Only modest differences in cell wall chemical composition could be detected, but we found that sos6-1 mutant plants accumulate high levels of reactive oxygen species (ROS) under osmotic stress and are hypersensitive to the oxidative stress reagent methyl viologen. The results suggest that SOS6/AtCSLD5 is not required for normal plant growth and development but has a critical role in osmotic stress tolerance and this function likely involves its regulation of ROS under stress. © 2010 Blackwell Publishing Ltd.

Induced Systemic Tolerance to Multiple Stresses Including Biotic and Abiotic Factors by Rhizobacteria

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Sung-Je Yoo

2017-06-01

Full Text Available Recently, global warming and drastic climate change are the greatest threat to the world. The climate change can affect plant productivity by reducing plant adaptation to diverse environments including frequent high temperature; worsen drought condition and increased pathogen transmission and infection. Plants have to survive in this condition with a variety of biotic (pathogen/pest attack and abiotic stress (salt, high/low temperature, drought. Plants can interact with beneficial microbes including plant growth-promoting rhizobacteria, which help plant mitigate biotic and abiotic stress. This overview presents that rhizobacteria plays an important role in induced systemic resistance (ISR to biotic stress or induced systemic tolerance (IST to abiotic stress condition; bacterial determinants related to ISR and/or IST. In addition, we describe effects of rhizobacteria on defense/tolerance related signal pathway in plants. We also review recent information including plant resistance or tolerance against multiple stresses (bioticabiotic. We desire that this review contribute to expand understanding and knowledge on the microbial application in a constantly varying agroecosystem, and suggest beneficial microbes as one of alternative environment-friendly application to alleviate multiple stresses.

Plant responses to water stress

Science.gov (United States)

Kar, Rup Kumar

2011-01-01

Terrestrial plants most often encounter drought stress because of erratic rainfall which has become compounded due to present climatic changes.Responses of plants to water stress may be assigned as either injurious change or tolerance index. One of the primary and cardinal changes in response to drought stress is the generation of reactive oxygen species (ROS), which is being considered as the cause of cellular damage. However, recently a signaling role of such ROS in triggering the ROS scavenging system that may confer protection or tolerance against stress is emerging. Such scavenging system consists of antioxidant enzymes like SOD, catalase and peroxidases, and antioxidant compounds like ascorbate, reduced glutathione; a balance between ROS generation and scavenging ultimately determines the oxidative load. As revealed in case of defence against pathogen, signaling via ROS is initiated by NADPH oxidase-catalyzed superoxide generation in the apoplastic space (cell wall) followed by conversion to hydrogen peroxide by the activity of cell wall-localized SOD. Wall peroxidase may also play role in ROS generation for signaling. Hydrogen peroxide may use Ca2+ and MAPK pathway as downstream signaling cascade. Plant hormones associated with stress responses like ABA and ethylene play their role possibly via a cross talk with ROS towards stress tolerance, thus projecting a dual role of ROS under drought stress. PMID:22057331

Arsenic tolerant Trichoderma sp. reduces arsenic induced stress in chickpea (Cicer arietinum).

Science.gov (United States)

Tripathi, Pratibha; Singh, Poonam C; Mishra, Aradhana; Srivastava, Suchi; Chauhan, Reshu; Awasthi, Surabhi; Mishra, Seema; Dwivedi, Sanjay; Tripathi, Preeti; Kalra, Alok; Tripathi, Rudra D; Nautiyal, Chandra S

2017-04-01

Toxic metalloids including arsenic (As) can neither be eliminated nor destroyed from environment; however, they can be converted from toxic to less/non-toxic forms. The form of As species and their concentration determines its toxicity in plants. Therefore, the microbe mediated biotransformation of As is crucial for its plant uptake and toxicity. In the present study the role of As tolerant Trichoderma in modulating As toxicity in chickpea plants was explored. Chickpea plants grown in arsenate spiked soil under green house conditions were inoculated with two plant growth promoting Trichoderma strains, M-35 (As tolerant) and PPLF-28 (As sensitive). Total As concentration in chickpea tissue was comparable in both the Trichoderma treatments, however, differences in levels of organic and inorganic As (iAs) species were observed. The shift in iAs to organic As species ratio in tolerant Trichoderma treatment correlated with enhanced plant growth and nutrient content. Arsenic stress amelioration in tolerant Trichoderma treatment was also evident through rhizospheric microbial community and anatomical studies of the stem morphology. Down regulation of abiotic stress responsive genes (MIPS, PGIP, CGG) in tolerant Trichoderma + As treatment as compared to As alone and sensitive Trichoderma + As treatment also revealed that tolerant strain enhanced the plant's potential to cope with As stress as compared to sensitive one. Considering the bioremediation and plant growth promotion potential, the tolerant Trichoderma may appear promising for its utilization in As affected fields for enhancing agricultural productivity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Overexpression of a Panax ginseng tonoplast aquaporin alters salt tolerance, drought tolerance and cold acclimation ability in transgenic Arabidopsis plants.

Science.gov (United States)

Peng, Yanhui; Lin, Wuling; Cai, Weiming; Arora, Rajeev

2007-08-01

Water movement across cellular membranes is regulated largely by a family of water channel proteins called aquaporins (AQPs). Since several abiotic stresses such as, drought, salinity and freezing, manifest themselves via altering water status of plant cells and are linked by the fact that they all result in cellular dehydration, we overexpressed an AQP (tonoplast intrinsic protein) from Panax ginseng, PgTIP1, in transgenic Arabidopsis thaliana plants to test its role in plant's response to drought, salinity and cold acclimation (induced freezing tolerance). Under favorable conditions, PgTIP1 overexpression significantly increased plant growth as determined by the biomass production, and leaf and root morphology. PgTIP1 overexpression had beneficial effect on salt-stress tolerance as indicated by superior growth status and seed germination of transgenic plants under salt stress; shoots of salt-stressed transgenic plants also accumulated greater amounts of Na(+) compared to wild-type plants. Whereas PgTIP1 overexpression diminished the water-deficit tolerance of plants grown in shallow (10 cm deep) pots, the transgenic plants were significantly more tolerant to water stress when grown in 45 cm deep pots. The rationale for this contrasting response, apparently, comes from the differences in the root morphology and leaf water channel activity (speed of dehydration/rehydration) between the transgenic and wild-type plants. Plants overexpressed with PgTIP1 exhibited lower (relative to wild-type control) cold acclimation ability; however, this response was independent of cold-regulated gene expression. Our results demonstrate a significant function of PgTIP1 in growth and development of plant cells, and suggest that the water movement across tonoplast (via AQP) represents a rate-limiting factor for plant vigor under favorable growth conditions and also significantly affect responses of plant to drought, salt and cold stresses.

Pathogenesis-related proteins and peptides as promising tools for engineering plants with multiple stress tolerance.

Science.gov (United States)

Ali, Sajad; Ganai, Bashir Ahmad; Kamili, Azra N; Bhat, Ajaz Ali; Mir, Zahoor Ahmad; Bhat, Javaid Akhter; Tyagi, Anshika; Islam, Sheikh Tajamul; Mushtaq, Muntazir; Yadav, Prashant; Rawat, Sandhya; Grover, Anita

Pathogenesis-related (PR) proteins and antimicrobial peptides (AMPs) are a group of diverse molecules that are induced by phytopathogens as well as defense related signaling molecules. They are the key components of plant innate immune system especially systemic acquired resistance (SAR), and are widely used as diagnostic molecular markers of defense signaling pathways. Although, PR proteins and peptides have been isolated much before but their biological function remains largely enigmatic despite the availability of new scientific tools. The earlier studies have demonstrated that PR genes provide enhanced resistance against both biotic and abiotic stresses, which make them one of the most promising candidates for developing multiple stress tolerant crop varieties. In this regard, plant genetic engineering technology is widely accepted as one of the most fascinating approach to develop the disease resistant transgenic crops using different antimicrobial genes like PR genes. Overexpression of PR genes (chitinase, glucanase, thaumatin, defensin and thionin) individually or in combination have greatly uplifted the level of defense response in plants against a wide range of pathogens. However, the detailed knowledge of signaling pathways that regulates the expression of these versatile proteins is critical for improving crop plants to multiple stresses, which is the future theme of plant stress biology. Hence, this review provides an overall overview on the PR proteins like their classification, role in multiple stresses (biotic and abiotic) as well as in various plant defense signaling cascades. We also highlight the success and snags of transgenic plants expressing PR proteins and peptides. Copyright © 2018 Elsevier GmbH. All rights reserved.

Temperature-stress resistance and tolerance along a latitudinal cline in North American Arabidopsis lyrata.

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Guillaume Wos

Full Text Available The study of latitudinal gradients can yield important insights into adaptation to temperature stress. Two strategies are available: resistance by limiting damage, or tolerance by reducing the fitness consequences of damage. Here we studied latitudinal variation in resistance and tolerance to frost and heat and tested the prediction of a trade-off between the two strategies and their costliness. We raised plants of replicate maternal seed families from eight populations of North American Arabidopsis lyrata collected along a latitudinal gradient in climate chambers and exposed them repeatedly to either frost or heat stress, while a set of control plants grew under standard conditions. When control plants reached maximum rosette size, leaf samples were exposed to frost and heat stress, and electrolyte leakage (PEL was measured and treated as an estimate of resistance. Difference in maximum rosette size between stressed and control plants was used as an estimate of tolerance. Northern populations were more frost resistant, and less heat resistant and less heat tolerant, but-unexpectedly-they were also less frost tolerant. Negative genetic correlations between resistance and tolerance to the same and different thermal stress were generally not significant, indicating only weak trade-offs. However, tolerance to frost was consistently accompanied by small size under control conditions, which may explain the non-adaptive latitudinal pattern for frost tolerance. Our results suggest that adaptation to frost and heat is not constrained by trade-offs between them. But the cost of frost tolerance in terms of plant size reduction may be important for the limits of species distributions and climate niches.

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

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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.

Improved tolerance to post-anthesis drought stress by pre-drought priming at vegetative stages in drought-tolerant and -sensitive wheat cultivars.

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Abid, Muhammad; Tian, Zhongwei; Ata-Ul-Karim, Syed Tahir; Liu, Yang; Cui, Yakun; Zahoor, Rizwan; Jiang, Dong; Dai, Tingbo

2016-09-01

Wheat crop endures a considerable penalty of yield reduction to escape the drought events during post-anthesis period. Drought priming under a pre-drought stress can enhance the crop potential to tolerate the subsequent drought stress by triggering a faster and stronger defense mechanism. Towards these understandings, a set of controlled moderate drought stress at 55-60% field capacity (FC) was developed to prime the plants of two wheat cultivars namely Luhan-7 (drought tolerant) and Yangmai-16 (drought sensitive) during tillering (Feekes 2 stage) and jointing (Feekes 6 stage), respectively. The comparative response of primed and non-primed plants, cultivars and priming stages was evaluated by applying a subsequent severe drought stress at 7 days after anthesis. The results showed that primed plants of both cultivars showed higher potential to tolerate the post-anthesis drought stress through improved leaf water potential, more chlorophyll, and ribulose-1, 5-bisphosphate carboxylase/oxygenase contents, enhanced photosynthesis, better photoprotection and efficient enzymatic antioxidant system leading to less yield reductions. The primed plants of Luhan-7 showed higher capability to adapt the drought stress events than Yangmai-16. The positive effects of drought priming to sustain higher grain yield were pronounced in plants primed at tillering than those primed at jointing. In consequence, upregulated functioning of photosynthetic apparatus and efficient enzymatic antioxidant activities in primed plants indicated their superior potential to alleviate a subsequently occurring drought stress, which contributed to lower yield reductions than non-primed plants. However, genotypic and priming stages differences in response to drought stress also contributed to affect the capability of primed plants to tolerate the post-anthesis drought stress conditions in wheat. Copyright © 2016. Published by Elsevier Masson SAS.

Trichoderma-Plant Root Colonization: Escaping Early Plant Defense Responses and Activation of the Antioxidant Machinery for Saline Stress Tolerance

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Brotman, Yariv; Landau, Udi; Cuadros-Inostroza, Álvaro; Takayuki, Tohge; Fernie, Alisdair R.; Chet, Ilan; Viterbo, Ada; Willmitzer, Lothar

2013-01-01

Trichoderma spp. are versatile opportunistic plant symbionts which can colonize the apoplast of plant roots. Microarrays analysis of Arabidopsis thaliana roots inoculated with Trichoderma asperelloides T203, coupled with qPCR analysis of 137 stress responsive genes and transcription factors, revealed wide gene transcript reprogramming, proceeded by a transient repression of the plant immune responses supposedly to allow root colonization. Enhancement in the expression of WRKY18 and WRKY40, which stimulate JA-signaling via suppression of JAZ repressors and negatively regulate the expression of the defense genes FMO1, PAD3 and CYP71A13, was detected in Arabidopsis roots upon Trichoderma colonization. Reduced root colonization was observed in the wrky18/wrky40 double mutant line, while partial phenotypic complementation was achieved by over-expressing WRKY40 in the wrky18 wrky40 background. On the other hand increased colonization rate was found in roots of the FMO1 knockout mutant. Trichoderma spp. stimulate plant growth and resistance to a wide range of adverse environmental conditions. Arabidopsis and cucumber (Cucumis sativus L.) plants treated with Trichoderma prior to salt stress imposition show significantly improved seed germination. In addition, Trichoderma treatment affects the expression of several genes related to osmo-protection and general oxidative stress in roots of both plants. The MDAR gene coding for monodehydroascorbate reductase is significantly up-regulated and, accordingly, the pool of reduced ascorbic acid was found to be increased in Trichoderma treated plants. 1-Aminocyclopropane-1-carboxylate (ACC)-deaminase silenced Trichoderma mutants were less effective in providing tolerance to salt stress, suggesting that Trichoderma, similarly to ACC deaminase producing bacteria, can ameliorate plant growth under conditions of abiotic stress, by lowering ameliorating increases in ethylene levels as well as promoting an elevated antioxidative capacity

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.

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

Science.gov (United States)

Hema, Ramanna; Vemanna, Ramu S; Sreeramulu, Shivakumar; Reddy, Chandrasekhara P; Senthil-Kumar, Muthappa; Udayakumar, Makarla

2014-01-01

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.

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. © 2014 Scandinavian Plant Physiology Society.

Constitutive and stress-inducible overexpression of a native aquaporin gene (MusaPIP2;6) in transgenic banana plants signals its pivotal role in salt tolerance.

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Sreedharan, Shareena; Shekhawat, Upendra K Singh; Ganapathi, Thumballi R

2015-05-01

High soil salinity constitutes a major abiotic stress and an important limiting factor in cultivation of crop plants worldwide. Here, we report the identification and characterization of a aquaporin gene, MusaPIP2;6 which is involved in salt stress signaling in banana. MusaPIP2;6 was firstly identified based on comparative analysis of stressed and non-stressed banana tissue derived EST data sets and later overexpression in transgenic banana plants was performed to study its tangible functions in banana plants. The overexpression of MusaPIP2;6 in transgenic banana plants using constitutive or inducible promoter led to higher salt tolerance as compared to equivalent untransformed control plants. Cellular localization assay performed using transiently transformed onion peel cells indicated that MusaPIP2;6 protein tagged with green fluorescent protein was translocated to the plasma membrane. MusaPIP2;6-overexpressing banana plants displayed better photosynthetic efficiency and lower membrane damage under salt stress conditions. Our results suggest that MusaPIP2;6 is involved in salt stress signaling and tolerance in banana.

Stress-inducible expression of AtDREB1A transcription factor greatly improves drought stress tolerance in transgenic indica rice.

Science.gov (United States)

Ravikumar, G; Manimaran, P; Voleti, S R; Subrahmanyam, D; Sundaram, R M; Bansal, K C; Viraktamath, B C; Balachandran, S M

2014-06-01

The cultivation of rice (Oryza sativa L.), a major food crop, requires ample water (30 % of the fresh water available worldwide), and its productivity is greatly affected by drought, the most significant environmental factor. Much research has focussed on identifying quantitative trait loci, stress-regulated genes and transcription factors that will contribute towards the development of climate-resilient/tolerant crop plants in general and rice in particular. The transcription factor DREB1A, identified from the model plant Arabidopsis thaliana, has been reported to enhance stress tolerance against drought stress. We developed transgenic rice plants with AtDREB1A in the background of indica rice cultivar Samba Mahsuri through Agrobacterium-mediated transformation. The AtDREB1A gene was stably inherited and expressed in T1 and T2 plants and in subsequent generations, as indicated by the results of PCR, Southern blot and RT-PCR analyses. Expression of AtDREB1A was induced by drought stress in transgenic rice lines, which were highly tolerant to severe water deficit stress in both the vegetative and reproductive stages without affecting their morphological or agronomic traits. The physiological studies revealed that the expression of AtDREB1A was associated with an increased accumulation of the osmotic substance proline, maintenance of chlorophyll, increased relative water content and decreased ion leakage under drought stress. Most of the homozygous lines were highly tolerant to drought stress and showed significantly a higher grain yield and spikelet fertility relative to the nontransgenic control plants under both stressed and unstressed conditions. The improvement in drought stress tolerance in combination with agronomic traits is very essential in high premium indica rice cultivars, such as Samba Mahsuri, so that farmers can benefit in times of seasonal droughts and water scarcity.

The enhancement of tolerance to salt and cold stresses by modifying the redox state and salicylic acid content via the cytosolic malate dehydrogenase gene in transgenic apple plants.

Science.gov (United States)

Wang, Qing-Jie; Sun, Hong; Dong, Qing-Long; Sun, Tian-Yu; Jin, Zhong-Xin; Hao, Yu-Jin; Yao, Yu-Xin

2016-10-01

In this study, we characterized the role of an apple cytosolic malate dehydrogenase gene (MdcyMDH) in the tolerance to salt and cold stresses and investigated its regulation mechanism in stress tolerance. The MdcyMDH transcript was induced by mild cold and salt treatments, and MdcyMDH-overexpressing apple plants possessed improved cold and salt tolerance compared to wild-type (WT) plants. A digital gene expression tag profiling analysis revealed that MdcyMDH overexpression largely altered some biological processes, including hormone signal transduction, photosynthesis, citrate cycle and oxidation-reduction. Further experiments verified that MdcyMDH overexpression modified the mitochondrial and chloroplast metabolisms and elevated the level of reducing power, primarily caused by increased ascorbate and glutathione, as well as the increased ratios of ascorbate/dehydroascorbate and glutathione/glutathione disulphide, under normal and especially stress conditions. Concurrently, the transgenic plants produced a high H2 O2 content, but a low O2·- production rate was observed compared to the WT plants. On the other hand, the transgenic plants accumulated more free and total salicylic acid (SA) than the WT plants under normal and stress conditions. Taken together, MdcyMDH conferred the transgenic apple plants a higher stress tolerance by producing more reductive redox states and increasing the SA level; MdcyMDH could serve as a target gene to genetically engineer salt- and cold-tolerant trees. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

The Novel Wheat Transcription Factor TaNAC47 Enhances Multiple Abiotic Stress Tolerances in Transgenic Plants.

Science.gov (United States)

Zhang, Lina; Zhang, Lichao; Xia, Chuan; Zhao, Guangyao; Jia, Jizeng; Kong, Xiuying

2015-01-01

NAC transcription factors play diverse roles in plant development and responses to abiotic stresses. However, the biological roles of NAC family members in wheat are not well understood. Here, we reported the isolation and functional characterization of a novel wheat TaNAC47 gene. TaNAC47 encoded protein, localizing in the nucleus, is able to bind to the ABRE cis-element and transactivate transcription in yeast, suggesting that it likely functions as a transcriptional activator. We also showed that TaNAC47 is differentially expressed in different tissues, and its expression was induced by the stress treatments of salt, cold, polyethylene glycol and exogenous abscisic acid. Furthermore, overexpression of TaNAC47 in Arabidopsis resulted in ABA hypersensitivity and enhancing tolerance of transgenic plants to drought, salt, and freezing stresses. Strikingly, overexpression of TaNAC47 was found to activate the expression of downstream genes and change several physiological indices that may enable transgenic plants to overcome unfavorable environments. Taken together, these results uncovered an important role of wheat TaNAC47 gene in response to ABA and abiotic stresses.

Wheat multiple synthetic derivatives: a new source for heat stress tolerance adaptive traits

Science.gov (United States)

Elbashir, Awad Ahmed Elawad; Gorafi, Yasir Serag Alnor; Tahir, Izzat Sidahmed Ali; Kim, June-Sik; Tsujimoto, Hisashi

2017-01-01

Heat stress is detrimental to wheat (Triticum aestivum L.) productivity. In this study, we aimed to select heat-tolerant plants from a multiple synthetic derivatives (MSD) population and evaluate their agronomic and physiological traits. We selected six tolerant plants from the population with the background of the cultivar ‘Norin 61’ (N61) and established six MNH (MSD population of N61 selected as heat stress-tolerant) lines. We grew these lines with N61 in the field and growth chamber. In the field, we used optimum and late sowings to ensure plant exposure to heat. In the growth chamber, in addition to N61, we used the heat-tolerant cultivars ‘Gelenson’ and ‘Bacanora’. We confirmed that MNH2 and MNH5 lines acquired heat tolerance. These lines had higher photosynthesis and stomata conductance and exhibited no reduction in grain yield and biomass under heat stress compared to N61. We noticed that N61 had relatively good adaptability to heat stress. Our results indicate that the MSD population includes the diversity of Aegilops tauschii and is a promising resource to uncover useful quantitative traits derived from this wild species. Selected lines could be useful for heat stress tolerance breeding. PMID:28744178

Stress tolerance and stress-induced injury in crop plants measured by chlorophyll fluorescence in vivo: chilling, freezing, ice cover, heat, and high light.

Science.gov (United States)

Smillie, R M; Hetherington, S E

1983-08-01

The proposition is examined that measurements of chlorophyll fluorescence in vivo can be used to monitor cellular injury caused by environmental stresses rapidly and nondestructively and to determine the relative stress tolerances of different species. Stress responses of leaf tissue were measured by F(R), the maximal rate of the induced rise in chlorophyll fluorescence. The time taken for F(R) to decrease by 50% in leaves at 0 degrees C was used as a measure of chilling tolerance. This value was 4.3 hours for chilling-sensitive cucumber. In contrast, F(R) decreased very slowly in cucumber leaves at 10 degrees C or in chilling-tolerant cabbage leaves at 0 degrees C. Long-term changes in F(R) of barley, wheat, and rye leaves kept at 0 degrees C were different in frost-hardened and unhardened material and in the latter appeared to be correlated to plant frost tolerance. To simulate damage caused by a thick ice cover, wheat leaves were placed at 0 degrees C under N(2). Kharkov wheat, a variety tolerant of ice encapsulation, showed a slower decrease in F(R) than Gatcher, a spring wheat. Relative heat tolerance was also indicated by the decrease in F(R) in heated leaves while changes in vivo resulting from photoinhibition, ultraviolet radiation, and photobleaching can also be measured.

Protective role of anthocyanins in plants under low nitrogen stress.

Science.gov (United States)

Liang, Jian; He, Junxian

2018-04-15

Nitrogen (N) is a major nutrient of plants but often a limiting factor for plant growth and crop yield. To adapt to N deficiency, plants have evolved adaptive responses including accumulation of anthocyanins. However, it is still unclear whether the accumulated anthocyanins are part of the components of plant tolerance under low N stress. Here, we demonstrate that low N-induced anthocyanins contribute substantially to the low N tolerance of Arabidopsis thaliana. pap1-1, a mutant defective in MYB75 (PAP1), a MYB-type transcription factor that positively regulates anthocyanin biosynthesis in Arabidopsis, was found to have significantly decreased survival rate to low N stress compared to its wild-type plants. Similarly, tt3, a mutant with severe deficiency in dihydroflavonol 4-reductase (DFR), a key enzyme in anthocyanin biosynthesis, also showed much lower survival rate under low N stress. These results indicate that anthocyanins are substantial contributors of plant tolerance to low N stress. Furthermore, a metabolomics analysis using LC-MS revealed changes in flavonoid profile in the pap1-1 and tt3 plants, which established a causal relationship between plant adaptation to low N stress and these compounds including anthocyanins. Our results showed an important role of anthocyanins rather than flavonols in conferring plant tolerance to low N stress. Copyright © 2018 Elsevier Inc. All rights reserved.

The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

KAUST Repository

Wang, Zhenyu

2011-05-01

Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

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.

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

KAUST Repository

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

2015-01-01

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.

Development of salt tolerant plants through genetic engineering (abstract)

International Nuclear Information System (INIS)

Mukhtar, Z.; Khan, S.A.; Zafar, Y.

2005-01-01

Salinity stress is one of the most serious factors limiting the productivity of agricultural crops. Genetic engineering provides a useful tool for tailoring plants with enhanced salt tolerance characteristics. Many organisms have evolved mechanisms to survive and grow under such extreme environments. These organisms provide us with a useful source of genes which can be used to improve salt tolerance in plants. The present study aims at identification and cloning of useful halo tolerance conferring genes from fungi and plants and to develop salt tolerant transgenic plants. Here we describe the cloning and use of HSR1 gene (a yeast transcription factor known to confer salt tolerance) and Na/sup +//H/sup +/ antiporter gene AtNHX1 (3016 bp) from Arabidopsis thaliana, and transformation of tobacco with HSR1 and AtNHX1 genes through Agrobacterium method. A number of transgenic tobacco plants were regenerated from leaf explants transformed with Agrobacterium tumefaciens (LBA4404) having HSR1 and AtNHX1 genes by leaf disc method. The putative transgenic plants were analyzed by PCR and dot blot analysis. Screening of these transgenic plants at different salinity levels is in progress which will help identify the suitable plant lines and thus the promising genes which can be further exploited to engineer salt tolerant crop plants. (author)

Plant plasma membrane proteomics for improving cold tolerance

Directory of Open Access Journals (Sweden)

Daisuke eTakahashi

2013-04-01

Full Text Available Plants are always exposed to various stresses. We have focused on freezing stress, which causes serious problems for agricultural management. When plants suffer freeze-induced damage, the plasma membrane is thought to be the primary site of injury because of its central role in regulation of various cellular processes. Cold tolerant species, however, adapt to such freezing conditions by modifying cellular components and functions (cold acclimation. One of the most important adaptation mechanisms to freezing is alteration of plasma membrane compositions and functions. Advanced proteomic technologies have succeeded in identification of many candidates that may play roles in adaptation of the plasma membrane to freezing stress. Proteomics results suggest that adaptations of plasma membrane functions to low temperature are associated with alterations of protein compositions during cold acclimation. Some of proteins identified by proteomic approaches have been verified their functional roles in freezing tolerance mechanisms further. Thus, accumulation of proteomic results in the plasma membrane is of importance for application to molecular breeding efforts to increase cold tolerance in crops.

Biotic and abiotic stress tolerance in transgenic tomatoes by constitutive expression of S-adenosylmethionine decarboxylase gene.

Science.gov (United States)

Hazarika, Pranjal; Rajam, Manchikatla Venkat

2011-04-01

Recent findings have implicated the role of polyamines (putrescine, spermidine and spermine) in stress tolerance. Therefore, the present work was carried out with the goal of generating transgenic tomato plants with human S-adenosylmethionine decarboxylase (samdc) gene, a key gene involved in biosynthesis of polyamines, viz. spermidine and spermine and evaluating the transgenic plants for tolerance to both biotic and abiotic stresses. Several putative transgenic tomato plants with normal phenotype were obtained, and the transgene integration and expression was validated by PCR, Southern blot analysis and RT-PCR analysis, respectively. The transgenic plants exhibited high levels of polyamines as compared to the untransformed control plants. They also showed increased resistance against two important fungal pathogens of tomato, the wilt causing Fusarium oxysporum and the early blight causing Alternaria solani and tolerance to multiple abiotic stresses such as salinity, drought, cold and high temperature. These results suggest that engineering polyamine accumulation can confer tolerance to both biotic and abiotic stresses in plants.

Improving abiotic stress tolerance of quinoa

DEFF Research Database (Denmark)

Yang, Aizheng

Global food security faces the challenges of rapid population growth and shortage of water resources. Drought, heat waves and soil salinity are becoming more frequent and extreme due to climatic changes in many regions of the world, and resulting in yield reduction of many crops. It is hypothesized...... 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...... other crops, its productivity declines under severe drought, high salt conditions and harsh climate conditions. Different management approaches including water-saving irrigation methods (such as deficit irrigation, DI and alternate root-zone drying irrigation, ARD), inoculating crop seeds with plant...

Evidence for an association in corn between stress tolerance and ...

African Journals Online (AJOL)

Evidence for an association in corn between stress tolerance and resistance to ... Further examination of host plant and pathogen interactions revealed that ... Key Words: Plant hormone, fungal infection, gene regulation, transcription factor.

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.

Characterization of a eukaryotic translation initiation factor 5A homolog from Tamarix androssowii involved in plant abiotic stress tolerance

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Wang Liuqiang

2012-07-01

Full Text Available Abstract Background The eukaryotic translation initiation factor 5A (eIF5A promotes formation of the first peptide bond at the onset of protein synthesis. However, the function of eIF5A in plants is not well understood. Results In this study, we characterized the function of eIF5A (TaeIF5A1 from Tamarix androssowii. The promoter of TaeIF5A1 with 1,486 bp in length was isolated, and the cis-elements in the promoter were identified. A WRKY (TaWRKY and RAV (TaRAV protein can specifically bind to a W-box motif in the promoter of TaeIF5A1 and activate the expression of TaeIF5A1. Furthermore, TaeIF5A1, TaWRKY and TaRAV share very similar expression pattern and are all stress-responsive gene that functions in the abscisic acid (ABA signaling pathway, indicating that they are components of a single regulatory pathway. Transgenic yeast and poplar expressing TaeIF5A1 showed elevated protein levels combined with improved abiotic stresses tolerance. Furthermore, TaeIF5A1-transformed plants exhibited enhanced superoxide dismutase (SOD and peroxidase (POD activities, lower electrolyte leakage and higher chlorophyll content under salt stress. Conclusions These results suggested that TaeIF5A1 is involved in abiotic stress tolerance, and is likely regulated by transcription factors TaWRKY and TaRAV both of which can bind to the W-box motif. In addition, TaeIF5A1 may mediate stress tolerance by increasing protein synthesis, enhancing ROS scavenging by improving SOD and POD activities, and preventing chlorophyll loss and membrane damage. Therefore, eIF5A may play an important role in plant adaptation to changing environmental conditions.

Characterization of a eukaryotic translation initiation factor 5A homolog from Tamarix androssowii involved in plant abiotic stress tolerance.

Science.gov (United States)

Wang, Liuqiang; Xu, Chenxi; Wang, Chao; Wang, Yucheng

2012-07-26

The eukaryotic translation initiation factor 5A (eIF5A) promotes formation of the first peptide bond at the onset of protein synthesis. However, the function of eIF5A in plants is not well understood. In this study, we characterized the function of eIF5A (TaeIF5A1) from Tamarix androssowii. The promoter of TaeIF5A1 with 1,486 bp in length was isolated, and the cis-elements in the promoter were identified. A WRKY (TaWRKY) and RAV (TaRAV) protein can specifically bind to a W-box motif in the promoter of TaeIF5A1 and activate the expression of TaeIF5A1. Furthermore, TaeIF5A1, TaWRKY and TaRAV share very similar expression pattern and are all stress-responsive gene that functions in the abscisic acid (ABA) signaling pathway, indicating that they are components of a single regulatory pathway. Transgenic yeast and poplar expressing TaeIF5A1 showed elevated protein levels combined with improved abiotic stresses tolerance. Furthermore, TaeIF5A1-transformed plants exhibited enhanced superoxide dismutase (SOD) and peroxidase (POD) activities, lower electrolyte leakage and higher chlorophyll content under salt stress. These results suggested that TaeIF5A1 is involved in abiotic stress tolerance, and is likely regulated by transcription factors TaWRKY and TaRAV both of which can bind to the W-box motif. In addition, TaeIF5A1 may mediate stress tolerance by increasing protein synthesis, enhancing ROS scavenging by improving SOD and POD activities, and preventing chlorophyll loss and membrane damage. Therefore, eIF5A may play an important role in plant adaptation to changing environmental conditions.

Impacts of priming with silicon on the growth and tolerance of maize plants to alkaline stress

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ِ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.

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. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

A Novel WRKY Transcription Factor, MuWRKY3 (Macrotyloma uniflorum Lam. Verdc. Enhances Drought Stress Tolerance in Transgenic Groundnut (Arachis hypogaea L. Plants

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Kurnool Kiranmai

2018-03-01

Full Text Available Drought stress has adverse effects on growth, water relations, photosynthesis and yield of groundnut. WRKY transcription factors (TFs are the plant-specific TFs which regulate several down-stream stress-responsive genes and play an essential role in plant biotic and abiotic stress responses. We found that WRKY3 gene is highly up-regulated under drought stress conditions and therefore isolated a new WRKY3TF gene from a drought-adapted horsegram (Macrotyloma uniflorum Lam. Verdc.. Conserved domain studies revealed that protein encoded by this gene contains highly conserved regions of two WRKY domains and two C2H2 zinc-finger motifs. The fusion protein localization studies of transient MuWRKY3-YFP revealed its nuclear localization. Overexpression of MuWRKY3 TF gene in groundnut (Arachis hypogaea L. showed increased tolerance to drought stress compared to wild-type (WT plants. MuWRKY3 groundnut transgenics displayed lesser and delayed wilting symptoms than WT plants after 10-days of drought stress imposition. The transgenic groundnut plants expressing MuWRKY3 showed less accumulation of malondialdehyde, hydrogen peroxide (H2O2, and superoxide anion (O2∙-, accompanied by more free proline, total soluble sugar content, and activities of antioxidant enzymes than WT plants under drought stress. Moreover, a series of stress-related LEA, HSP, MIPS, APX, SOD, and CAT genes found up-regulated in the transgenic groundnut plants. The study demonstrates that nuclear-localized MuWRKY3 TF regulates the expression of stress-responsive genes and the activity of ROS scavenging enzymes which results in improved drought tolerance in groundnut. We conclude that MuWRKY3 may serve as a new putative candidate gene for the improvement of stress resistance in plants.

A Novel WRKY Transcription Factor, MuWRKY3 (Macrotyloma uniflorum Lam. Verdc.) Enhances Drought Stress Tolerance in Transgenic Groundnut (Arachis hypogaea L.) Plants.

Science.gov (United States)

Kiranmai, Kurnool; Lokanadha Rao, Gunupuru; Pandurangaiah, Merum; Nareshkumar, Ambekar; Amaranatha Reddy, Vennapusa; Lokesh, Uppala; Venkatesh, Boya; Anthony Johnson, A M; Sudhakar, Chinta

2018-01-01

Drought stress has adverse effects on growth, water relations, photosynthesis and yield of groundnut. WRKY transcription factors (TFs) are the plant-specific TFs which regulate several down-stream stress-responsive genes and play an essential role in plant biotic and abiotic stress responses. We found that WRKY3 gene is highly up-regulated under drought stress conditions and therefore isolated a new WRKY3TF gene from a drought-adapted horsegram ( Macrotyloma uniflorum Lam. Verdc.). Conserved domain studies revealed that protein encoded by this gene contains highly conserved regions of two WRKY domains and two C2H2 zinc-finger motifs. The fusion protein localization studies of transient MuWRKY 3-YFP revealed its nuclear localization. Overexpression of MuWRKY3 TF gene in groundnut ( Arachis hypogaea L.) showed increased tolerance to drought stress compared to wild-type (WT) plants. MuWRKY3 groundnut transgenics displayed lesser and delayed wilting symptoms than WT plants after 10-days of drought stress imposition. The transgenic groundnut plants expressing MuWRKY3 showed less accumulation of malondialdehyde, hydrogen peroxide (H 2 O 2 ), and superoxide anion (O 2 ∙- ), accompanied by more free proline, total soluble sugar content, and activities of antioxidant enzymes than WT plants under drought stress. Moreover, a series of stress-related LEA, HSP, MIPS, APX, SOD , and CAT genes found up-regulated in the transgenic groundnut plants. The study demonstrates that nuclear-localized MuWRKY3 TF regulates the expression of stress-responsive genes and the activity of ROS scavenging enzymes which results in improved drought tolerance in groundnut. We conclude that MuWRKY3 may serve as a new putative candidate gene for the improvement of stress resistance in plants.

The novel wheat transcription factor TaNAC47 enhances multiple abiotic stress tolerances in transgenic plants

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Li Na eZhang

2016-01-01

Full Text Available NAC transcription factors play diverse roles in plant development and responses to abiotic stresses. However, the biological roles of NAC family members in wheat are not well understood. Here, we reported the isolation and functional characterization of a novel wheat TaNAC47 gene. TaNAC47 encoded protein, localizing in the nucleus, is able to bind to the ABRE cis-element and transactivate transcription in yeast, suggesting that it likely functions as a transcriptional activator. We also showed that TaNAC47 is differentially expressed in different tissues, and its expression was induced by the stress treatments of salt, cold, polyethylene glycol (PEG and exogenous abscisic acid (ABA. Furthermore, overexpression of TaNAC47 in Arabidopsis resulted in ABA hypersensitivity and enhancing tolerance of transgenic plants to drought, salt and freezing stresses. Strikingly, overexpression of TaNAC47 was found to activate the expression of downstream genes and change several physiological indices that may enable transgenic plants to overcome unfavorable environments. Taken together, these results uncovered an important role of wheat TaNAC47 gene in response to ABA and abiotic stresses.

Drought-Tolerant Plant Growth-Promoting Rhizobacteria Associated with Foxtail Millet in a Semi-arid Agroecosystem and Their Potential in Alleviating Drought Stress

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Xuguang Niu

2018-01-01

Full Text Available The application of plant growth promoting rhizobacteria (PGPR to agro-ecosystems is considered to have the potential for improving plant growth in extreme environments featured by water shortage. Herein, we isolated bacterial strains from foxtail millet (Setaria italica L., a drought-tolerant crop cultivated in semiarid regions in the northeast of China. Four isolates were initially selected for their ability to produce ACC deaminase as well as drought tolerance. The isolates were identified as Pseudomonas fluorescens, Enterobacter hormaechei, and Pseudomonas migulae on the basis of 16S rRNA sequence analysis. All of these drought-tolerant isolates were able to produce EPS (exopolysaccharide. Inoculation with these strains stimulated seed germination and seedling growth under drought stress. Pseudomonas fluorescens DR7 showed the highest level of ACC deaminase and EPS-producing activity. DR7 could efficiently colonize the root adhering soil, increased soil moisture, and enhance the root adhering soil/root tissue ratio. These results suggest drought tolerant PGPR from foxtail millet could enhance plant growth under drought stress conditions and serve as effective bioinoculants to sustain agricultural production in arid regions.

Overexpression of a Pathogenesis-Related Protein 10 Enhances Biotic and Abiotic Stress Tolerance in Rice

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Jingni Wu

2016-12-01

Full Text Available Pathogenesis-related proteins play multiple roles in plant development and biotic and abiotic stress tolerance. Here, we characterize a rice defense related gene named “jasmonic acid inducible pathogenesis-related class 10” (JIOsPR10 to gain an insight into its functional properties. Semi-quantitative RT-PCR analysis showed up-regulation of JIOsPR10 under salt and drought stress conditions. Constitutive over-expression JIOsPR10 in rice promoted shoot and root development in transgenic plants, however, their productivity was unaltered. Further experiments exhibited that the transgenic plants showed reduced susceptibility to rice blast fungus, and enhanced salt and drought stress tolerance as compared to the wild type. A comparative proteomic profiling of wild type and transgenic plants showed that overexpression of JIOsPR10 led to the differential modulation of several proteins mainly related with oxidative stresses, carbohydrate metabolism, and plant defense. Taken together, our findings suggest that JIOsPR10 plays important roles in biotic and abiotic stresses tolerance probably by activation of stress related proteins.

Tolerance of wheat and lettuce plants grown on human mineralized waste to high temperature stress

Science.gov (United States)

Ushakova, Sofya A.; Tikhomirov, Alexander A.; Shikhov, Valentin N.; Gros, Jean-Bernard; Golovko, Tamara K.; Dal'ke, Igor V.; Zakhozhii, Ilya G.

2013-06-01

The main objective of a life support system for space missions is to supply a crew with food, water and oxygen, and to eliminate their wastes. The ultimate goal is to achieve the highest degree of closure of the system using controlled processes offering a high level of reliability and flexibility. Enhancement of closure of a biological life support system (BLSS) that includes plants relies on increased regeneration of plant waste, and utilization of solid and liquid human wastes. Clearly, the robustness of a BLSS subjected to stress will be substantially determined by the robustness of the plant components of the phototrophic unit. The aim of the present work was to estimate the heat resistance of two plants (wheat and lettuce) grown on human wastes. Human exometabolites mineralized by hydrogen peroxide in an electromagnetic field were used to make a nutrient solution for the plants. We looked for a possible increase in the heat tolerance of the wheat plants using changes in photosynthetically active radiation (PAR) intensity during heat stress. At age 15 days, plants were subjected to a rise in air temperature (from 23 ± 1 °C to 44 ± 1 °С) under different PAR intensities for 4 h. The status of the photosynthetic apparatus of the plants was assessed by external СО2 gas exchange and fluorescence measurements. The increased irradiance of the plants during the high temperature period demonstrated its protective action for both the photosynthetic apparatus of the leaves and subsequent plant growth and development. The productivity of the plants subjected to temperature changes at 250 W m-2 of PAR did not differ from that of controls, whereas the productivity of the plants subjected to the same heat stress but in darkness was halved.

Roles of Protein Synthesis Elongation Factor EF-Tu in Heat Tolerance in Plants

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Jianming Fu

2012-01-01

Full Text Available EF-Tu proteins of plastids, mitochondria, and the cytosolic counterpart EF-1α in plants, as well as EF-Tu proteins of bacteria, are highly conserved and multifunctional. The functions of EF-Tu include transporting the aminoacyl-tRNA complex to the A site of the ribosome during protein biosynthesis; chaperone activity in protecting other proteins from aggregation caused by environmental stresses, facilitating renaturation of proteins when conditions return to normal; displaying a protein disulfide isomerase activity; participating in the degradation of N-terminally blocked proteins by the proteasome; eliciting innate immunity and triggering resistance to pathogenic bacteria in plants; participating in transcription when an E. coli host is infected with phages. EF-Tu genes are upregulated by abiotic stresses in plants, and EF-Tu plays important role in stress responses. Expression of a plant EF-Tu gene confers heat tolerance in E. coli, maize knock-out EF-Tu null mutants are heat susceptible, and over-expression of an EF-Tu gene improves heat tolerance in crop plants. This review paper summarizes the current knowledge of EF-Tu proteins in stress responses in plants and progress on application of EF-Tu for developing crop varieties tolerant to abiotic stresses, such as high temperatures.

Stress-tolerant mutants induced by heavy-ion beams

International Nuclear Information System (INIS)

Abe, Tomoko; Yoshida, Shigeo; Bae, Chang-Hyu; Ozaki, Takuo

2000-01-01

Comparative study was made on mutagenesis in tobacco embryo induced by exposure to EMS (ethyl methane-sulfonate) ion beams during the fertilization cycle. Tobacco embryo cells immediately after pollination were exposed to heavy ion beam and the sensitivity to the irradiation was assessed in each developmental stage and compared with the effects of EMS, a chemical mutagen. Morphologically abnormality such as chlorophyll deficiency was used as a marker. A total of 17 salt-tolerant plants were selected from 3447 M 1 seeds. A cell line showed salt resistance. The cell growth and chlorophyll content were each two times higher than that of WT cells in the medium containing 154 mM NaCl. Seven strains of M 3 progeny of 17 salt-tolerant plants, showed strong resistance, but no salt tolerant progeny were obtained from Xanthi or Ne-ion irradiation. This shows that the sensitivity of plant embryo to this irradiation technique may vary among species. When exposed to 14 N ion beam for 24-108 hours after pollination, various morphological mutants appeared at 18% in M 1 progeny and herbicide tolerant and salt tolerant mutants were obtained. A strong Co-tolerant strain was obtained in two of 17 salt-tolerant strains and a total of 46 tolerant strains (0.2%) were obtained from 22,272 grains of M 1 seeds. In these tolerant strains, the absorption of Co was slightly decreased, but those of Mg and Mn were increased. Mutants induced with ion-beam irradiation have potential not only for practical use in the breeding of stress-tolerant plants but also for gene analysis that will surely facilitate the molecular understanding of the tolerance mechanisms. (M.N.)

Ammonia stress on nitrogen metabolism in tolerant aquatic plant-Myriophyllum aquaticum.

Science.gov (United States)

Zhou, Qingyang; Gao, Jingqing; Zhang, Ruimin; Zhang, Ruiqin

2017-09-01

Ammonia has been a major reason of macrophyte decline in the water environment, and ammonium ion toxicity should be seen as universal, even in species frequently labeled as "NH 4 + specialists". To study the effects of high NH 4 + -N stress of ammonium ion nitrogen on tolerant submerged macrophytes and investigate the pathways of nitrogen assimilation in different organisms, Myriophyllum aquaticum was selected and treated with various concentrations of ammonium ions at different times. Increasing of ammonium concentration leads to an overall increase in incipient ammonia content in leaves and stems of plants. In middle and later stages, high concentrations of NH 4 + ion nitrogen taken up by M. aquaticum decreased, whereas the content of NO 3 - ion nitrogen increased. Moreover, in M. aquaticum, the activities of the enzymes nitrate reductase, glutamine synthetase and asparagine synthetase changed remarkably in the process of alleviating NH 4 + toxicity and deficiency. The results of the present study may support the studies on detoxification of high ammonium ion content in NH 4 + -tolerant submerged macrophytes and exploration of tissue-specific expression systems. Copyright © 2017. Published by Elsevier Inc.

Aluminium exclusion and aluminium tolerance in woody plants

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Ivano eBrunner

2013-06-01

Full Text Available The aluminium (Al cation Al3+ is highly rhizotoxic and is a major stress factor to plants on acid soils, which cover large areas of tropical and boreal regions. Many woody plant species are native to acid soils and are well adapted to high Al3+ conditions. In tropical regions, both woody Al accumulator and non-Al accumulator plants occur, whereas in boreal regions woody plants are non-Al accumulators. The mechanisms of these adaptations can be divided into those that facilitate the exclusion of Al3+ from root cells (exclusion mechanisms and those that enable plants to tolerate Al3+ once it has entered the root and shoot symplast (internal tolerance mechanisms. The biochemical and molecular basis of these mechanisms have been intensively studied in several crop plants and the model plant Arabidopsis. In this review, we examine the current understanding of Al3+ exclusion and tolerance mechanisms from woody plants. In addition, we discuss the ecology of woody non-Al accumulator and Al accumulator plants, and present examples of Al3+ adaptations in woody plant populations. This paper complements previous reviews focusing on crop plants and provides insights into evolutionary processes operating in plant communities that are widespread on acid soils.

Aluminum exclusion and aluminum tolerance in woody plants.

Science.gov (United States)

Brunner, Ivano; Sperisen, Christoph

2013-01-01

The aluminum (Al) cation Al(3) (+) is highly rhizotoxic and is a major stress factor to plants on acid soils, which cover large areas of tropical and boreal regions. Many woody plant species are native to acid soils and are well adapted to high Al(3) (+) conditions. In tropical regions, both woody Al accumulator and non-Al accumulator plants occur, whereas in boreal regions woody plants are non-Al accumulators. The mechanisms of these adaptations can be divided into those that facilitate the exclusion of Al(3) (+) from root cells (exclusion mechanisms) and those that enable plants to tolerate Al(3) (+) once it has entered the root and shoot symplast (internal tolerance mechanisms). The biochemical and molecular basis of these mechanisms have been intensively studied in several crop plants and the model plant Arabidopsis. In this review, we examine the current understanding of Al(3) (+) exclusion and tolerance mechanisms from woody plants. In addition, we discuss the ecology of woody non-Al accumulator and Al accumulator plants, and present examples of Al(3) (+) adaptations in woody plant populations. This paper complements previous reviews focusing on crop plants and provides insights into evolutionary processes operating in plant communities that are widespread on acid soils.

Stress inducible overexpression of AtHDG11 leads to improved drought and salt stress tolerance in peanut (Arachis hypogaea L.)

Science.gov (United States)

Banavath, Jayanna N.; Chakradhar, Thammineni; Pandit, Varakumar; Konduru, Sravani; Guduru, Krishna K.; Akila, Chandra S.; Podha, Sudhakar; Puli, Chandra O. R.

2018-03-01

Peanut is an important oilseed and food legume cultivated as a rain-fed crop in semi-arid tropics. Drought and high salinity are the major abiotic stresses limiting the peanut productivity in this region. Development of drought and salt tolerant peanut varieties with improved yield potential using biotechnological approach is highly desirable to improve the peanut productivity in marginal geographies. As abiotic stress tolerance and yield represent complex traits, engineering of regulatory genes to produce abiotic stress-resilient transgenic crops appears to be a viable approach. In the present study, we developed transgenic peanut plants expressing an Arabidopsis homeodomain-leucine zipper transcription factor (AtHDG11) under stress inducible rd29Apromoter. A stress-inducible expression of AtHDG11 in three independent homozygous transgenic peanut lines resulted in improved drought and salt tolerance through up-regulation of known stress responsive genes(LEA, HSP70, Cu/Zn SOD, APX, P5CS, NCED1, RRS5, ERF1, NAC4, MIPS, Aquaporin, TIP, ELIP ) in the stress gene network , antioxidative enzymes, free proline along with improved water use efficiency traits such as longer root system, reduced stomatal density, higher chlorophyll content, increased specific leaf area, improved photosynthetic rates and increased intrinsic instantaneous WUE. Transgenic peanut plants displayed high yield compared to non-transgenic plants under both drought and salt stress conditions. Holistically, our study demonstrates the potentiality of stress-induced expression of AtHDG11 to improve the drought, salt tolerance in peanut.

Metabolic profiles of flooding-tolerant mechanism in early-stage soybean responding to initial stress.

Science.gov (United States)

Wang, Xin; Zhu, Wei; Hashiguchi, Akiko; Nishimura, Minoru; Tian, Jingkui; Komatsu, Setsuko

2017-08-01

Metabolomic analysis of flooding-tolerant mutant and abscisic acid-treated soybeans suggests that accumulated fructose might play a role in initial flooding tolerance through regulation of hexokinase and phosphofructokinase. Soybean is sensitive to flooding stress, which markedly reduces plant growth. To explore the mechanism underlying initial-flooding tolerance in soybean, mass spectrometry-based metabolomic analysis was performed using flooding-tolerant mutant and abscisic-acid treated soybeans. Among the commonly-identified metabolites in both flooding-tolerant materials, metabolites involved in carbohydrate and organic acid displayed same profile at initial-flooding stress. Sugar metabolism was highlighted in both flooding-tolerant materials with the decreased and increased accumulation of sucrose and fructose, respectively, compared to flooded soybeans. Gene expression of hexokinase 1 was upregulated in flooded soybean; however, it was downregulated in both flooding-tolerant materials. Metabolites involved in carbohydrate/organic acid and proteins related to glycolysis/tricarboxylic acid cycle were integrated. Increased protein abundance of phosphofructokinase was identified in both flooding-tolerant materials, which was in agreement with its enzyme activity. Furthermore, sugar metabolism was pointed out as the tolerant-responsive process at initial-flooding stress with the integration of metabolomics, proteomics, and transcriptomics. Moreover, application of fructose declined the increased fresh weight of plant induced by flooding stress. These results suggest that fructose might be the critical metabolite through regulation of hexokinase and phosphofructokinase to confer initial-flooding stress in soybean.

Heavy metal tolerance in plants: Role of transcriptomics, proteomics, metabolomics and ionomics

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Samiksha eSingh

2016-02-01

Full Text Available Heavy metal contamination of soil and water causing toxicity/stress has become one important constraint to crop productivity and quality. This situation has further worsened by the increasing population growth and inherent food demand. It have been reported in several studies that counterbalancing toxicity, due to heavy metal requires complex mechanisms at molecular, biochemical, physiological, cellular, tissue and whole plant level, which might manifest in terms of improved crop productivity. Recent advances in various disciplines of biological sciences such as metabolomics, transcriptomics, proteomics etc. have assisted in the characterization of metabolites, transcription factors, stress-inducible proteins involved in heavy metal tolerance, which in turn can be utilized for generating heavy metal tolerant crops. This review summarizes various tolerance strategies of plants under heavy metal toxicity, covering the role of metabolites (metabolomics, trace elements (ionomics, transcription factors (transcriptomics, various stress-inducible proteins (proteomics as well as the role of plant hormones. We also provide a glance at strategies adopted by metal accumulating plants also known as metallophytes.

Heavy Metal Tolerance in Plants: Role of Transcriptomics, Proteomics, Metabolomics, and Ionomics

Science.gov (United States)

Singh, Samiksha; Parihar, Parul; Singh, Rachana; Singh, Vijay P.; Prasad, Sheo M.

2016-01-01

Heavy metal contamination of soil and water causing toxicity/stress has become one important constraint to crop productivity and quality. This situation has further worsened by the increasing population growth and inherent food demand. It has been reported in several studies that counterbalancing toxicity due to heavy metal requires complex mechanisms at molecular, biochemical, physiological, cellular, tissue, and whole plant level, which might manifest in terms of improved crop productivity. Recent advances in various disciplines of biological sciences such as metabolomics, transcriptomics, proteomics, etc., have assisted in the characterization of metabolites, transcription factors, and stress-inducible proteins involved in heavy metal tolerance, which in turn can be utilized for generating heavy metal-tolerant crops. This review summarizes various tolerance strategies of plants under heavy metal toxicity covering the role of metabolites (metabolomics), trace elements (ionomics), transcription factors (transcriptomics), various stress-inducible proteins (proteomics) as well as the role of plant hormones. We also provide a glance of some strategies adopted by metal-accumulating plants, also known as “metallophytes.” PMID:26904030

Salt-Stress effects on crop plants: Role of proline, glycinebetaine and calcium at whole-plant and cellular levels

International Nuclear Information System (INIS)

Akhtar, L.H.; Gorham, J.; Siddiqui, S.Z.; Jamil, M.; Arshad, M.

2002-01-01

Salinity affects the physiological and biochemical processes of the plants in a variety of ways. In this manuscript, variability in plant, with respect to salinity-tolerance and morphological adaptations in plants for salinity-tolerance, have been discussed. Salinity effects on growth of plants, cell membranes, proteins, sugars, nucleic acids, starch, cell sap, transpiration, stomatal conductance, pollen viability, Co/sub 2/ assimilation, chlorophyll, photosynthesis and enzymes have been reviewed. Proline and glycinebetaine accumulation, localisation in the cell and their physiological role under salt-stress has been presented. Cellular mechanism of salt-tolerance and role of calcium in salt-stress have been reviewed. The possible approaches to deal with all types of stresses have been suggested. (author)

Stress-tolerant mutants induced by heavy-ion beams

Energy Technology Data Exchange (ETDEWEB)

Abe, Tomoko; Yoshida, Shigeo [Institute of Physical and Chemical Research, Wako, Saitama (Japan); Bae, Chang-Hyu [Sunchon National University, Sunchon (Korea); Ozaki, Takuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Wang, Jing Ming [Akita Prefectural Univ. (Japan)

2000-07-01

Comparative study was made on mutagenesis in tobacco embryo induced by exposure to EMS (ethyl methane-sulfonate) ion beams during the fertilization cycle. Tobacco embryo cells immediately after pollination were exposed to heavy ion beam and the sensitivity to the irradiation was assessed in each developmental stage and compared with the effects of EMS, a chemical mutagen. Morphologically abnormality such as chlorophyll deficiency was used as a marker. A total of 17 salt-tolerant plants were selected from 3447 M{sub 1} seeds. A cell line showed salt resistance. The cell growth and chlorophyll content were each two times higher than that of WT cells in the medium containing 154 mM NaCl. Seven strains of M{sub 3} progeny of 17 salt-tolerant plants, showed strong resistance, but no salt tolerant progeny were obtained from Xanthi or Ne-ion irradiation. This shows that the sensitivity of plant embryo to this irradiation technique may vary among species. When exposed to {sup 14}N ion beam for 24-108 hours after pollination, various morphological mutants appeared at 18% in M{sub 1} progeny and herbicide tolerant and salt tolerant mutants were obtained. A strong Co-tolerant strain was obtained in two of 17 salt-tolerant strains and a total of 46 tolerant strains (0.2%) were obtained from 22,272 grains of M{sub 1} seeds. In these tolerant strains, the absorption of Co was slightly decreased, but those of Mg and Mn were increased. Mutants induced with ion-beam irradiation have potential not only for practical use in the breeding of stress-tolerant plants but also for gene analysis that will surely facilitate the molecular understanding of the tolerance mechanisms. (M.N.)

Pea p68, a DEAD-box helicase, provides salinity stress tolerance in transgenic tobacco by reducing oxidative stress and improving photosynthesis machinery.

Science.gov (United States)

Tuteja, Narendra; Banu, Mst Sufara Akhter; Huda, Kazi Md Kamrul; Gill, Sarvajeet Singh; Jain, Parul; Pham, Xuan Hoi; Tuteja, Renu

2014-01-01

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. 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. 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.

Enhanced salt tolerance of transgenic poplar plants expressing a manganese superoxide dismutase from Tamarix androssowii.

Science.gov (United States)

Wang, Yu Cheng; Qu, Guan Zheng; Li, Hong Yan; Wu, Ying Jie; Wang, Chao; Liu, Gui Feng; Yang, Chuan Ping

2010-02-01

Superoxide dismutases (SODs) play important role in stress tolerance of plants. In this study, an MnSOD gene (TaMnSOD) from Tamarix androssowii, under the control of the CaMV35S promoter, was introduced into poplar (Populus davidiana x P. bolleana). The physiological parameters, including SOD activity, malondialdehyde (MDA) content, relative electrical conductivity (REC) and relative weight gain, of transgenic lines and wild type (WT) plants, were measured and compared. The results showed that SOD activity was enhanced in transgenic plants, and the MDA content and REC were significantly decreased compared to WT plants when exposed to NaCl stress. In addition, the relative weight gains of the transgenic plants were 8- to 23-fold of those observed for WT plants after NaCl stress for 30 days. The data showed that the SOD activities that increased in transgenic lines are 1.3-4-folds of that increased in the WT plant when exposed to NaCl stress. Our analysis showed that increases in SOD activities as low as 0.15-fold can also significantly enhance salt tolerance in transgenic plants, suggesting an important role of increased SOD activity in plant salt tolerance

Rhizospheric salt tolerant bacteria improving plant growth in single and mixed culture inoculations under NaCl stress (abstract)

International Nuclear Information System (INIS)

Afrasayab, S.; Hasnain, S.

2005-01-01

Salt tolerant bacterial strains isolated from rhizosphere of Mazus plant (inhabitant of salt range) were used singly (ST -1; ST -2; ST -3; ST -4) and in mixed combinations (ST -1,3,4; ST -2,3,4) to improve the growth to Tricticum aestivum in the pot experiments. Growth and yield of T. aestivum var. Inqlab-91 plants exposed to NaCl stress (0.75% NaCl) was markedly affected. Na/sup +//K/sup +/ ratios in shoots and roots were profoundly increased under NaCl stress. Bacterial inoculations improved plant growth under salt stress. Bacterial combinations ST - 1,3,4 and ST -2,3,4 were more effective in stimulating growth and showed prominent results as compared to their pure cultures. Mono and mixed bacterial inoculations improved yield parameters of wheat. ST -1,3,4 mixed culture inoculation maximally improved yield under salt stress. Generally bacterial inoculations resulted in increase in Na/sup +//K/sup +/ ratios in shoots and roots under salt free and salt stress conditions. Overall ST -1,3,4 mixed inoculation yielded promising results under NaCl stress, hence 168 rRNA gene sequence analysis of its pure cultures was obtained for their identification to genus level. (author)

Screening of drought oxidative stress tolerance in Serbian ...

African Journals Online (AJOL)

This study was designed to examine and compare antioxidant and free-radical scavenging activities of leaves of six different melliferous plant species (Populus alba, Robinia pseudoacacia, Sophora japonica, Euodia hupehensis, Tilia sp., Fraxinus sp.) from Serbia in order to evaluate their drought oxidative stress tolerance.

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.

Transcription factors and plant response to drought stress: Current understanding and future directions

Directory of Open Access Journals (Sweden)

Rohit Joshi

2016-07-01

Full Text Available Increasing vulnerability of plants to a variety of stresses such as drought, salt and extreme temperatures poses a global threat to sustained growth and productivity of major crops. Of these stresses, drought represents a considerable threat to plant growth and development. In view of this, developing staple food cultivars with improved drought tolerance emerges as the most sustainable solution towards improving crop productivity in a scenario of climate change. In parallel, unraveling the genetic architecture and the targeted identification of molecular networks using modern OMICS analyses, that can underpin drought tolerance mechanisms, is urgently required. Importantly, integrated studies intending to elucidate complex mechanisms can bridge the gap existing in our current knowledge about drought stress tolerance in plants. It is now well established that drought tolerance is regulated by several genes, including transcription factors (TFs that enable plants to withstand unfavorable conditions, and these remain potential genomic candidates for their wide application in crop breeding. These TFs represent the key molecular switches orchestrating the regulation of plant developmental processes in response to a variety of stresses. The current review aims to offer a deeper understanding of TFs engaged in regulating plant’s response under drought stress and to devise potential strategies to improve plant tolerance against drought.

Air pollution tolerance indices of some plants around Ama industrial ...

African Journals Online (AJOL)

SAM

2014-03-12

Mar 12, 2014 ... Table 1. Air pollution tolerance index (APTI) of some plant species around some industries in Ama, Enugu State, Nigeria. Plant specie. Site .... these receive most impact from the pollution load in the environment. APTI is an inherent quality of plants to encounter air pollution stress (Rai et al., 2013). These.

Arbuscular Mycorrhizal Fungi Enhance Basil Tolerance to Salt Stress through Improved Physiological and Nutritional Status

International Nuclear Information System (INIS)

Salwa, A.; Abeer, H.; Alqarawi, A. A.; Abdullah, E.F.; Egamberdieva, D.

2016-01-01

Pot experiments were conducted to evaluate the influence of salinity on some physio-biochemical traits in sweet basil (Ocimum basilicum L.) cultivars with contrasting salt stress tolerance and to determine the role of arbuscular mycorrhizal fungi (AMF) in ameliorating the salt stress in plant. Salt stress (250 mM NaCl) reduced the colonization potential of AMF and inhibited photosynthetic pigments, chlorophyll and carotenoids in plant tissue. AMF inoculated plants contained higher level of chlorophyll pigments. Salt stressed plants showed increased lipid peroxidation, antioxidant enzyme activities like superoxide dismutase (SOD), ascorbate peroxidase (APX) and peroxidase (POD). Plants inoculated with AMF showed lower lipid peroxidation and enhanced antioxidant enzyme activities. Moreover, the content of lipids, proline, and soluble sugars in basil plants was improved with AMF inoculation. AMF inoculation reduced accumulation of Na+ and improved nutrient acquisition. In conclusion, AMF were capable to reduce oxidative stress via supporting of the antioxidant system. Salt tolerant cultivar showed higher antioxidant enzyme activity and accumulation of osmolytes. (author)

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 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.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.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.

Lipidomics Unravels the Role of Leaf Lipids in Thyme Plant Response to Drought Stress

Directory of Open Access Journals (Sweden)

Parviz Moradi

2017-09-01

Full Text Available Thymus is one of the best known genera within the Labiatae (Lamiaceae family, with more than 200 species and many medicinal and culinary uses. The effects of prolonged drought on lipid profile were investigated in tolerant and sensitive thyme plants (Thymus serpyllum L. and Thymus vulgaris L., respectively. Non-targeted non-polar metabolite profiling was carried out using Fourier transform ion cyclotron resonance (FT-ICR mass spectrometry with one-month-old plants exposed to drought stress, and their morpho-physiological parameters were also evaluated. Tolerant and sensitive plants exhibited clearly different responses at a physiological level. In addition, different trends for a number of non-polar metabolites were observed when comparing stressed and control samples, for both sensitive and tolerant plants. Sensitive plants showed the highest decrease (55% in main lipid components such as galactolipids and phospholipids. In tolerant plants, the level of lipids involved in signaling increased, while intensities of those induced by stress (e.g., oxylipins dramatically decreased (50–60%, in particular with respect to metabolites with m/z values of 519.3331, 521.3488, and 581.3709. Partial least square discriminant analysis separated all the samples into four groups: tolerant watered, tolerant stressed, sensitive watered and sensitive stressed. The combination of lipid profiling and physiological parameters represented a promising tool for investigating the mechanisms of plant response to drought stress at non-polar metabolome level.

A cellulose synthase-like protein is required for osmotic stress tolerance in Arabidopsis

KAUST Repository

Zhu, Jianhua; Lee, Byeongha; Dellinger, Michael T.; Cui, Xinping; Zhang, Changqing; Wu, Shang; Nothnagel, Eugene A.; Zhu, Jian-Kang

2010-01-01

Osmotic stress imposed by soil salinity and drought stress significantly affects plant growth and development, but osmotic stress sensing and tolerance mechanisms are not well understood. Forward genetic screens using a root-bending assay have

Heat priming induces trans-generational tolerance to high temperature stress in wheat

Directory of Open Access Journals (Sweden)

Xiao eWang

2016-04-01

Full Text Available Wheat plants are very sensitive to high temperature stress during grain filling. Effects of heat priming applied to the first generation on tolerance of the successive generation to post-anthesis high temperature stress were investigated. Compared with the progeny of non-heat primed plants (NH, the progeny of heat-primed plants (PH possessed higher grain yield, leaf photosynthesis and activities of antioxidant enzymes and lower cell membrane damage under high temperature stress. In the transcriptome profile, 1430 probes showed obvious difference in expression between PH and NH. These genes were related to signal transduction, transcription, energy, defense, and protein destination and storage, respectively. The gene encoding the lysine-specific histone demethylase 1 (LSD1 which was involved in histone demethylation related to epigenetic modification was up-regulated in the PH compared with NH. The proteome analysis indicated that the proteins involved in photosynthesis, energy production and protein destination and storage were up-regulated in the PH compared with NH. In short, thermos-tolerance was induced through heritable epigenetic alternation and signaling transduction, both processes further triggered prompt modifications of defense related responses in anti-oxidation, transcription, energy production, and protein destination and storage in the progeny of the primed plants under high temperature stress. It was concluded that trans-generation thermo-tolerance was induced by heat priming in the first generation, and this might be an effective measure to cope with severe high-temperature stresses during key growth stages in wheat production.

The Solanum lycopersicum WRKY3 Transcription Factor SlWRKY3 Is Involved in Salt Stress Tolerance in Tomato

Czech Academy of Sciences Publication Activity Database

Hichri, I.; Muhovski, Y.; Žižková, Eva; Dobrev, Petre; Gharbi, E.; Franco-Zorrilla, J.M.; Lopez-Vidriero, I.; Solano, R.; Clippe, A.; Errachid, A.; Motyka, Václav; Lutts, S.

2017-01-01

Roč. 8, JUL 31 (2017), č. článku 1343. ISSN 1664-462X R&D Projects: GA ČR(CZ) GA16-14649S Institutional support: RVO:61389030 Keywords : agrobacterium-mediated transformation * transgenic arabidopsis plants * dna-binding * salinity tolerance * defense responses * drought tolerance * abiotic stresses * water-stress * genes * tobacco * Solanum lycopersicum * SlWRKY3 * transcription factor * salinity tolerance * plant physiology Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 4.298, year: 2016

Plant responses to environmental stresses-from gene to biotechnology.

Science.gov (United States)

Ahanger, Mohammad Abass; Akram, Nudrat Aisha; Ashraf, Muhammad; Alyemeni, Mohammed Nasser; Wijaya, Leonard; Ahmad, Parvaiz

2017-07-01

Increasing global population, urbanization and industrialization are increasing the rate of conversion of arable land into wasteland. Supplying food to an ever-increasing population is one of the biggest challenges that agriculturalists and plant scientists are currently confronting. Environmental stresses make this situation even graver. Despite the induction of several tolerance mechanisms, sensitive plants often fail to survive under environmental extremes. New technological approaches are imperative. Conventional breeding methods have a limited potential to improve plant genomes against environmental stress. Recently, genetic engineering has contributed enormously to the development of genetically modified varieties of different crops such as cotton, maize, rice, canola and soybean. The identification of stress-responsive genes and their subsequent introgression or overexpression within sensitive crop species are now being widely carried out by plant scientists. Engineering of important tolerance pathways, like antioxidant enzymes, osmolyte accumulation, membrane-localized transporters for efficient compartmentation of deleterious ions and accumulation of essential elements and resistance against pests or pathogens is also an area that has been intensively researched. In this review, the role of biotechnology and its successes, prospects and challenges in developing stress-tolerant crop cultivars are discussed.

Molecular and Evolutionary Mechanisms of Cuticular Wax for Plant Drought Tolerance

Directory of Open Access Journals (Sweden)

Dawei Xue

2017-04-01

Full Text Available Cuticular wax, the first protective layer of above ground tissues of many plant species, is a key evolutionary innovation in plants. Cuticular wax safeguards the evolution from certain green algae to flowering plants and the diversification of plant taxa during the eras of dry and adverse terrestrial living conditions and global climate changes. Cuticular wax plays significant roles in plant abiotic and biotic stress tolerance and has been implicated in defense mechanisms against excessive ultraviolet radiation, high temperature, bacterial and fungal pathogens, insects, high salinity, and low temperature. Drought, a major type of abiotic stress, poses huge threats to global food security and health of terrestrial ecosystem by limiting plant growth and crop productivity. The composition, biochemistry, structure, biosynthesis, and transport of plant cuticular wax have been reviewed extensively. However, the molecular and evolutionary mechanisms of cuticular wax in plants in response to drought stress are still lacking. In this review, we focus on potential mechanisms, from evolutionary, molecular, and physiological aspects, that control cuticular wax and its roles in plant drought tolerance. We also raise key research questions and propose important directions to be resolved in the future, leading to potential applications of cuticular wax for water use efficiency in agricultural and environmental sustainability.

Simultaneous Expression of PDH45 with EPSPS Gene Improves Salinity and Herbicide Tolerance in Transgenic Tobacco Plants.

Science.gov (United States)

Garg, Bharti; Gill, Sarvajeet S; Biswas, Dipul K; Sahoo, Ranjan K; Kunchge, Nandkumar S; Tuteja, Renu; Tuteja, Narendra

2017-01-01

To cope with the problem of salinity- and weed-induced crop losses, a multi-stress tolerant trait is need of the hour but a combinatorial view of such traits is not yet explored. The overexpression of PDH45 (pea DNA helicase 45) and EPSPS (5-enoylpruvyl shikimate-3-phosphate synthase) genes have been reported to impart salinity and herbicide tolerance. Further, the understanding of mechanism and pathways utilized by PDH45 and EPSPS for salinity and herbicide tolerance will help to improve the crops of economical importance. In the present study, we have performed a comparative analysis of salinity and herbicide tolerance to check the biochemical parameters and antioxidant status of tobacco transgenic plants. Collectively, the results showed that PDH45 overexpressing transgenic lines display efficient tolerance to salinity stress, while PDH45+EPSPS transgenics showed tolerance to both the salinity and herbicide as compared to the control [wild type (WT) and vector control (VC)] plants. The activities of the components of enzymatic antioxidant machinery were observed to be higher in the transgenic plants indicating the presence of an efficient antioxidant defense system which helps to cope with the stress-induced oxidative-damages. Photosynthetic parameters also showed significant increase in PDH45 and PDH45+EPSPS overexpressing transgenic plants in comparison to WT, VC and EPSPS transgenic plants under salinity stress. Furthermore, PDH45 and PDH45+EPSPS synergistically modulate the jasmonic acid and salicylic acid mediated signaling pathways for combating salinity stress. The findings of our study suggest that pyramiding of the PDH45 gene with EPSPS gene renders host plants tolerant to salinity and herbicide by enhancing the antioxidant machinery thus photosynthesis.

Ethylene induced plant stress tolerance by Enterobacter sp. SA187 is mediated by 2‐keto‐4‐methylthiobutyric acid production

KAUST Repository

Zé licourt, Axel de; Synek, Lukas; Saad, Maged; Alzubaidy, Hanin S.; Jalal, Rewaa Sauod Mohammed; Xie, Yakun; Andres-Barrao, Cristina; Rolli, Eleonora; Guerard, Florence; Mariappan, Kiruthiga; Daur, Ihsanullah; Colcombet, Jean; Benhamed, Moussa; Depaepe, Thomas; Van Der Straeten, Dominique; Hirt, Heribert

2018-01-01

of mechanisms related to the beneficial association of SA187 with plants. SA187 colonizes both the surface and inner tissues of Arabidopsis roots and shoots. SA187 induces salt stress tolerance by production of bacterial 2-keto-4-methylthiobutyric acid (KMBA

The garlic NF-YC gene, AsNF-YC8, positively regulates non-ionic hyperosmotic stress tolerance in tobacco.

Science.gov (United States)

Sun, Xiudong; Lian, Haifeng; Liu, Xingchen; Zhou, Shumei; Liu, Shiqi

2017-05-01

To investigate the relationship between nuclear factor Y (NF-Y) and stress tolerance in garlic, we cloned a NF-Y family gene AsNF-YC8 from garlic, which was largely upregulated at dehydrate stage. Expression pattern analyses in garlic revealed that AsNF-YC8 is induced through abscisic acid (ABA) and abiotic stresses, such as NaCl and PEG. Compared with wild-type plants, the overexpressing-AsNF-YC8 transgenic tobacco plants showed higher seed germination rates, longer root length and better plant growth under salt and drought stresses. Under drought stress, the transgenic plants maintained higher relative water content (RWC), net photosynthesis, lower levels of malondialdehyde (MDA), and less ion leakage (IL) than wild-type control plants. These results indicate the high tolerance of the transgenic plants to drought stress compared to the WT. The transgenic tobacco lines accumulated less reactive oxygen species (ROS) and exhibited higher antioxidative enzyme activities compared with wild-type (WT) plants under drought stress, which suggested that the overexpression of AsNF-YC8 improves the antioxidant defense system by regulating the activities of these antioxidant enzymes, which in turn protect transgenic lines against drought stress. These results suggest that AsNF-YC8 plays an important role in tolerance to drought and salt stresses.

Over-expression of a novel JAZ family gene from Glycine soja, increases salt and alkali stress tolerance

International Nuclear Information System (INIS)

Zhu, Dan; Cai, Hua; Luo, Xiao; Bai, Xi; Deyholos, Michael K.; Chen, Qin; Chen, Chao; Ji, Wei; Zhu, Yanming

2012-01-01

Highlights: ► We isolated and characterized a novel JAZ family gene, GsJAZ2, from Glycine soja. ► Overexpression of GsJAZ2 enhanced plant tolerance to salt and alkali stress. ► The transcriptions of stress marker genes were higher in GsJAZ2 overexpression lines. ► 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.

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

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.

A Nucleus-localized Long Non-Coding RNA Enhances Drought and Salt Stress Tolerance

KAUST Repository

Qin, Tao

2017-09-09

Long non-coding RNAs (lncRNAs) affect gene expression through a wide range of mechanisms and are considered as important regulators in many essential biological processes. A large number of lncRNA transcripts have been predicted or identified in plants in recent years. However, the biological functions for most of them are still unknown. In this study, we identified an Arabidopsis thaliana lncRNA, Drought induced RNA (DRIR), as a novel positive regulator of plant response to drought and salt stress. DRIR was expressed at a low level under non-stress conditions but can be significantly activated by drought and salt stress as well as by abscisic acid (ABA) treatment. We identified a T-DNA insertion mutant, drirD, which had higher expression of the DRIR gene than the wild type plants. The drirD mutant exhibits increased tolerance to drought and salt stress. Overexpressing DRIR in Arabidopsis also increased tolerance to drought and salt stress of the transgenic plants. The drirD mutant and the overexpressing seedlings are more sensitive to ABA than the wild type in stomata closure and seedling growth. Genome-wide transcriptome analysis demonstrated that the expression of a large number of genes was altered in drirD and the overexpressing plants. These include genes involved in ABA signaling, water transport and other stress-relief processes. Our study reveals a mechanism whereby DRIR regulates plant response to abiotic stress by modulating the expression of a series of genes involved in stress response.

Ectopic expression of TaOEP16-2-5B, a wheat plastid outer envelope protein gene, enhances heat and drought stress tolerance in transgenic Arabidopsis plants.

Science.gov (United States)

Zang, Xinshan; Geng, Xiaoli; Liu, Kelu; Wang, Fei; Liu, Zhenshan; Zhang, Liyuan; Zhao, Yue; Tian, Xuejun; Hu, Zhaorong; Yao, Yingyin; Ni, Zhongfu; Xin, Mingming; Sun, Qixin; Peng, Huiru

2017-05-01

Abiotic stresses, such as heat and drought, are major environmental factors restricting crop productivity and quality worldwide. A plastid outer envelope protein gene, TaOEP16-2, was identified from our previous transcriptome analysis [1,2]. In this study, the isolation and functional characterization of the TaOEP16-2 gene was reported. Three homoeologous sequences of TaOEP16-2 were isolated from hexaploid wheat, which were localized on the chromosomes 5A, 5B and 5D, respectively. These three homoeologues exhibited different expression patterns under heat stress conditions, TaOEP16-2-5B was the dominant one, and TaOEP16-2-5B was selected for further analysis. Compared with wild type (WT) plants, transgenic Arabidopsis plants overexpressing the TaOEP16-2-5B gene exhibited enhanced tolerance to heat stress, which was supported by improved survival rate, strengthened cell membrane stability and increased sucrose content. It was also found that TaOEP16-2 was induced by drought stress and involved in drought stress tolerance. TaOEP16-2-5B has the same function in ABA-controlled seed germination as AtOEP16-2. Our results suggest that TaOEP16-2-5B plays an important role in heat and drought stress tolerance, and could be utilized in transgenic breeding of wheat and other crop plants. Copyright © 2017 Elsevier B.V. All rights reserved.

Effectiveness of halo-tolerant, auxin producing Pseudomonas and Rhizobium strains to improve osmotic stress tolerance in mung bean (Vigna radiata L.

Directory of Open Access Journals (Sweden)

Maqshoof Ahmad

2013-12-01

Full Text Available Halo-tolerant, auxin producing bacteria could be used to induce salt tolerance in plants. A number of Rhizobium and auxin producing rhizobacterial strains were assessed for their ability to tolerate salt stress by conducting osmoadaptation assay. The selected strains were further screened for their ability to induce osmotic stress tolerance in mung bean seedlings under salt-stressed axenic conditions in growth pouch/jar trials. Three most effective strains of Rhizobium and Pseudomonas containing ACC-deaminase were evaluated in combination, for their ability to induce osmotic stress tolerance in mung bean at original, 4, and 6 dS m-1 under axenic conditions. Results showed that sole inoculation of Rhizobium and Pseudomonas strains improved the total dry matter up to 1.4, and 1.9 fold, respectively, while the increase in salt tolerance index was improved up to 1.3 and 2.0 fold by the Rhizobium and Pseudomonas strains, respectively. However, up to 2.2 fold increase in total dry matter and salt tolerance index was observed due to combined inoculation of Rhizobium and Pseudomonas strains. So, combined application of Rhizobium and Pseudomonas strains could be explored as an effective strategy to induce osmotic stress tolerance in mung bean.

Tolerance of Mycorrhiza infected pistachio (Pistacia vera L.) seedling to drought stress under glasshouse conditions.

Science.gov (United States)

Abbaspour, H; Saeidi-Sar, S; Afshari, H; Abdel-Wahhab, M A

2012-05-01

The influence of Glomus etunicatum colonization on plant growth and drought tolerance of 3-month-old Pistacia vera seedlings in potted culture was studied in two different water treatments. The arbuscular mycorrhiza (AM) inoculation and plant growth (including plant shoot and root weight, leaf area, and total chlorophyll) were higher for well-watered than for water-stressed plants. The growth of AM-treated seedlings was higher than non-AM-treatment regardless of water status. P, K, Zn and Cu contents in AM-treated shoots were greater than those in non-AM shoots under well-watered conditions and drought stress. N and Ca content were higher under drought stress, while AM symbiosis did not affect the Mg content. The contents of soluble sugars, proteins, flavonoid and proline were higher in mycorrhizal than non-mycorrhizal-treated plants under the whole water regime. AM colonization increased the activities of peroxidase enzyme in treatments, but did not affect the catalase activity in shoots and roots under well-watered conditions and drought stress. We conclude that AM colonization improved the drought tolerance of P. vera seedlings by increasing the accumulation of osmotic adjustment compounds, nutritional and antioxidant enzyme activity. It appears that AM formation enhanced the drought tolerance of pistachio plants, which increased host biomass and plant growth. Copyright © 2012 Elsevier GmbH. All rights reserved.

Analysis of Stress-Responsive Gene Expression in Cultivated and Weedy Rice Differing in Cold Stress Tolerance.

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Caroline Borges Bevilacqua

Full Text Available Rice (Oryza sativa L. cultivars show impairment of growth in response to environmental stresses such as cold at the early seedling stage. Locally adapted weedy rice is able to survive under adverse environmental conditions, and can emerge in fields from greater soil depth. Cold-tolerant weedy rice can be a good genetic source for developing cold-tolerant, weed-competitive rice cultivars. An in-depth analysis is presented here of diverse indica and japonica rice genotypes, mostly weedy rice, for cold stress response to provide an understanding of different stress adaptive mechanisms towards improvement of the rice crop performance in the field. We have tested a collection of weedy rice genotypes to: 1 classify the subspecies (ssp. grouping (japonica or indica of 21 accessions; 2 evaluate their sensitivity to cold stress; and 3 analyze the expression of stress-responsive genes under cold stress and a combination of cold and depth stress. Seeds were germinated at 25°C at 1.5- and 10-cm sowing depth for 10d. Seedlings were then exposed to cold stress at 10°C for 6, 24 and 96h, and the expression of cold-, anoxia-, and submergence-inducible genes was analyzed. Control plants were seeded at 1.5cm depth and kept at 25°C. The analysis revealed that cold stress signaling in indica genotypes is more complex than that of japonica as it operates via both the CBF-dependent and CBF-independent pathways, implicated through induction of transcription factors including OsNAC2, OsMYB46 and OsF-BOX28. When plants were exposed to cold + sowing depth stress, a complex signaling network was induced that involved cross talk between stresses mediated by CBF-dependent and CBF-independent pathways to circumvent the detrimental effects of stresses. The experiments revealed the importance of the CBF regulon for tolerance to both stresses in japonica and indica ssp. The mechanisms for cold tolerance differed among weedy indica genotypes and also between weedy indica and

Exogenous Glutathione Enhances Mercury Tolerance by Inhibiting Mercury Entry into Plant Cells

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Kim, Yeon-Ok; Bae, Hyeun-Jong; Cho, Eunjin; Kang, Hunseung

2017-01-01

Despite the increasing understanding of the crucial roles of glutathione (GSH) in cellular defense against heavy metal stress as well as oxidative stress, little is known about the functional role of exogenous GSH in mercury (Hg) tolerance in plants. Here, we provide compelling evidence that GSH contributes to Hg tolerance in diverse plants. Exogenous GSH did not mitigate the toxicity of cadmium (Cd), copper (Cu), or zinc (Zn), whereas application of exogenous GSH significantly promoted Hg tolerance during seed germination and seedling growth of Arabidopsis thaliana, tobacco, and pepper. By contrast, addition of buthionine sulfoximine, an inhibitor of GSH biosynthesis, severely retarded seed germination and seedling growth of the plants in the presence of Hg. The effect of exogenous GSH on Hg specific tolerance was also evident in the presence of other heavy metals, such as Cd, Cu, and Zn, together with Hg. GSH treatment significantly decreased H2O2 and O2- levels and lipid peroxidation, but increased chlorophyll content in the presence of Hg. Importantly, GSH treatment resulted in significantly less accumulation of Hg in Arabidopsis plants, and thin layer chromatography and nuclear magnetic resonance analysis revealed that GSH had much stronger binding affinity to Hg than to Cd, Cu, or Zn, suggesting that tight binding of GSH to Hg impedes Hg uptake, leading to low Hg accumulation in plant cells. Collectively, the present findings reveal that GSH is a potent molecule capable of conferring Hg tolerance by inhibiting Hg accumulation in plants. PMID:28507557

Exogenous Glutathione Enhances Mercury Tolerance by Inhibiting Mercury Entry into Plant Cells

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Yeon-Ok Kim

2017-05-01

Full Text Available Despite the increasing understanding of the crucial roles of glutathione (GSH in cellular defense against heavy metal stress as well as oxidative stress, little is known about the functional role of exogenous GSH in mercury (Hg tolerance in plants. Here, we provide compelling evidence that GSH contributes to Hg tolerance in diverse plants. Exogenous GSH did not mitigate the toxicity of cadmium (Cd, copper (Cu, or zinc (Zn, whereas application of exogenous GSH significantly promoted Hg tolerance during seed germination and seedling growth of Arabidopsis thaliana, tobacco, and pepper. By contrast, addition of buthionine sulfoximine, an inhibitor of GSH biosynthesis, severely retarded seed germination and seedling growth of the plants in the presence of Hg. The effect of exogenous GSH on Hg specific tolerance was also evident in the presence of other heavy metals, such as Cd, Cu, and Zn, together with Hg. GSH treatment significantly decreased H2O2 and O2- levels and lipid peroxidation, but increased chlorophyll content in the presence of Hg. Importantly, GSH treatment resulted in significantly less accumulation of Hg in Arabidopsis plants, and thin layer chromatography and nuclear magnetic resonance analysis revealed that GSH had much stronger binding affinity to Hg than to Cd, Cu, or Zn, suggesting that tight binding of GSH to Hg impedes Hg uptake, leading to low Hg accumulation in plant cells. Collectively, the present findings reveal that GSH is a potent molecule capable of conferring Hg tolerance by inhibiting Hg accumulation in plants.

Unwinding after high salinity stress: Pea DNA helicase 45 over- expression in tobacco confers high salinity tolerance without affecting yield (abstract)

International Nuclear Information System (INIS)

Tuteja, N.

2005-01-01

Soil salinity is an increasing threat for agriculture and is a major factor in reducing plant productivity; therefore, it is necessary to obtain salinity-tolerant varieties. A typical characteristic of soil salinity is the induction of multiple stress- inducible genes. Some of the genes encoding osmolytes, ion channels or enzymes are able to confer salinity-tolerant phenotypes when transferred to sensitive plants. As salinity stress affects the cellular gene-expression machinery, it is evident that molecules involved in nucleic acid processing including helicases, are likely to be affected as well. DNA helicases unwind duplex DNA and are involved in replication, repair, recombination and transcription while RNA helicases unfold the secondary structures in RNA and are involved in transcription, ribosome biogenesis and translation initiation. We have earlier reported the isolation of a pea DNA helicase 45 (PDH45) that exhibits striking homology with eIF-4A (Plant J. 24:219-230,2000). Here we report that PDH45 mRNA is induced in pea seedlings in response to high salt and its over- expression driven by a constitutive CAMV-355-promoter in tobacco plants confers salinity tolerance, thus suggesting a new pathway for manipulating stress tolerance in crop plants. The T0 transgenic plants showed high-levels of PDH45 protein in normal and stress conditions, as compared to wild type (WT) plants. The T0 transgenics also showed tolerance to high salinity as tested by a leaf disc senescence assay. The T1 transgenics were able to grow to maturity and set normal viable seeds under continuous salinity stress, without any reduction in plant yield, in terms of seed weight. Measurement of Na/sup +/ ions in different parts of the plant showed higher accumulation in the old leaves and negligible in seeds of T1 transgenic lines as compared with the WT plants. The possible mechanism of salinity tolerance will be discussed. Over-expression of PDH45 provides a possible example of the

Understanding abiotic stress tolerance mechanisms in soybean: a comparative evaluation of soybean response to drought and flooding stress.

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Mutava, Raymond N; Prince, Silvas Jebakumar K; Syed, Naeem Hasan; Song, Li; Valliyodan, Babu; Chen, Wei; Nguyen, Henry T

2015-01-01

Many sources of drought and flooding tolerance have been identified in soybean, however underlying molecular and physiological mechanisms are poorly understood. Therefore, it is important to illuminate different plant responses to these abiotic stresses and understand the mechanisms that confer tolerance. Towards this goal we used four contrasting soybean (Glycine max) genotypes (PI 567690--drought tolerant, Pana--drought susceptible, PI 408105A--flooding tolerant, S99-2281--flooding susceptible) grown under greenhouse conditions and compared genotypic responses to drought and flooding at the physiological, biochemical, and cellular level. We also quantified these variations and tried to infer their role in drought and flooding tolerance in soybean. Our results revealed that different mechanisms contribute to reduction in net photosynthesis under drought and flooding stress. Under drought stress, ABA and stomatal conductance are responsible for reduced photosynthetic rate; while under flooding stress, accumulation of starch granules played a major role. Drought tolerant genotypes PI 567690 and PI 408105A had higher plastoglobule numbers than the susceptible Pana and S99-2281. Drought stress increased the number and size of plastoglobules in most of the genotypes pointing to a possible role in stress tolerance. Interestingly, there were seven fibrillin proteins localized within the plastoglobules that were up-regulated in the drought and flooding tolerant genotypes PI 567690 and PI 408105A, respectively, but down-regulated in the drought susceptible genotype Pana. These results suggest a potential role of Fibrillin proteins, FBN1a, 1b and 7a in soybean response to drought and flooding stress. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

The grapevine VvWRKY2 gene enhances salt and osmotic stress tolerance in transgenic Nicotiana tabacum.

Science.gov (United States)

Mzid, Rim; Zorrig, Walid; Ben Ayed, Rayda; Ben Hamed, Karim; Ayadi, Mariem; Damak, Yosra; Lauvergeat, Virginie; Hanana, Mohsen

2018-06-01

Our study aims to assess the implication of WRKY transcription factor in the molecular mechanisms of grapevine adaptation to salt and water stresses. In this respect, a full-length VvWRKY2 cDNA, isolated from a Vitis vinifera grape berry cDNA library, was constitutively over-expressed in Nicotiana tabacum seedlings. Our results showed that transgenic tobacco plants exhibited higher seed germination rates and better growth, under both salt and osmotic stress treatments, when compared to wild type plants. Furthermore, our analyses demonstrated that, under stress conditions, transgenic plants accumulated more osmolytes, such as soluble sugars and free proline, while no changes were observed regarding electrolyte leakage, H 2 O 2 , and malondialdehyde contents. The improvement of osmotic adjustment may be an important mechanism underlying the role of VvWRKY 2 in promoting tolerance and adaptation to abiotic stresses. Principal component analysis of our results highlighted a clear partition of plant response to stress. On the other hand, we observed a significant adaptation behaviour response for transgenic lines under stress. Taken together, all our findings suggest that over-expression of VvWRKY2 gene has a compelling role in abiotic stress tolerance and, therefore, would provide a useful strategy to promote abiotic stress tolerance in grape via molecular-assisted breeding and/or new biotechnology tools.

Ectopic expression of specific GA2 oxidase mutants promotes yield and stress tolerance in rice.

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Lo, Shuen-Fang; Ho, Tuan-Hua David; Liu, Yi-Lun; Jiang, Mirng-Jier; Hsieh, Kun-Ting; Chen, Ku-Ting; Yu, Lin-Chih; Lee, Miin-Huey; Chen, Chi-Yu; Huang, Tzu-Pi; Kojima, Mikiko; Sakakibara, Hitoshi; Chen, Liang-Jwu; Yu, Su-May

2017-07-01

A major challenge of modern agricultural biotechnology is the optimization of plant architecture for enhanced productivity, stress tolerance and water use efficiency (WUE). To optimize plant height and tillering that directly link to grain yield in cereals and are known to be tightly regulated by gibberellins (GAs), we attenuated the endogenous levels of GAs in rice via its degradation. GA 2-oxidase (GA2ox) is a key enzyme that inactivates endogenous GAs and their precursors. We identified three conserved domains in a unique class of C 20 GA2ox, GA2ox6, which is known to regulate the architecture and function of rice plants. We mutated nine specific amino acids in these conserved domains and observed a gradient of effects on plant height. Ectopic expression of some of these GA2ox6 mutants moderately lowered GA levels and reprogrammed transcriptional networks, leading to reduced plant height, more productive tillers, expanded root system, higher WUE and photosynthesis rate, and elevated abiotic and biotic stress tolerance in transgenic rice. Combinations of these beneficial traits conferred not only drought and disease tolerance but also increased grain yield by 10-30% in field trials. Our studies hold the promise of manipulating GA levels to substantially improve plant architecture, stress tolerance and grain yield in rice and possibly in other major crops. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Over-expression of a novel JAZ family gene from Glycine soja, increases salt and alkali stress tolerance.

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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. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

Analysis of Brassica oleracea early stage abiotic stress responses reveals tolerance in multiple crop types and for multiple sources of stress.

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Beacham, Andrew M; Hand, Paul; Pink, David Ac; Monaghan, James M

2017-12-01

Brassica oleracea includes a number of important crop types such as cabbage, cauliflower, broccoli and kale. Current climate conditions and weather patterns are causing significant losses in these crops, meaning that new cultivars with improved tolerance of one or more abiotic stress types must be sought. In this study, genetically fixed B. oleracea lines belonging to a Diversity Fixed Foundation Set (DFFS) were assayed for their response to seedling stage-imposed drought, flood, salinity, heat and cold stress. Significant (P ≤ 0.05) variation in stress tolerance response was found for each stress, for each of four measured variables (relative fresh weight, relative dry weight, relative leaf number and relative plant height). Lines tolerant to multiple stresses were found to belong to several different crop types. There was no overall correlation between the responses to the different stresses. Abiotic stress tolerance was identified in multiple B. oleracea crop types, with some lines exhibiting resistance to multiple stresses. For each stress, no one crop type appeared significantly more or less tolerant than others. The results are promising for the development of more environmentally robust lines of different B. oleracea crops by identifying tolerant material and highlighting the relationship between responses to different stresses. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Overexpression of Late Embryogenesis Abundant 14 enhances Arabidopsis salt stress tolerance

International Nuclear Information System (INIS)

Jia, Fengjuan; Qi, Shengdong; Li, Hui; Liu, Pu; Li, Pengcheng; Wu, Changai; Zheng, Chengchao; Huang, Jinguang

2014-01-01

Highlights: • It is the first time to investigate the biological function of AtLEA14 in salt stress response. • AtLEA14 enhances the salt stress tolerance both in Arabidopsis and yeast. • AtLEA14 responses to salt stress by stabilizing AtPP2-B11, an E3 ligase, under normal or salt stress conditions. - Abstract: Late embryogenesis abundant (LEA) proteins are implicated in various abiotic stresses in higher plants. In this study, we identified a LEA protein from Arabidopsis thaliana, AtLEA14, which was ubiquitously expressed in different tissues and remarkably induced with increased duration of salt treatment. Subcellular distribution analysis demonstrated that AtLEA14 was mainly localized in the cytoplasm. Transgenic Arabidopsis and yeast overexpressing AtLEA14 all exhibited enhanced tolerance to high salinity. The transcripts of salt stress-responsive marker genes (COR15a, KIN1, RD29B and ERD10) were overactivated in AtLEA14 overexpressing lines compared with those in wild type plants under normal or salt stress conditions. In vivo and in vitro analysis showed that AtLEA14 could effectively stabilize AtPP2-B11, an important E3 ligase. These results suggested that AtLEA14 had important protective functions under salt stress conditions in Arabidopsis

Overexpression of Late Embryogenesis Abundant 14 enhances Arabidopsis salt stress tolerance

Energy Technology Data Exchange (ETDEWEB)

Jia, Fengjuan, E-mail: jfj.5566@163.com; Qi, Shengdong, E-mail: zisexanwu@163.com; Li, Hui, E-mail: 332453593@qq.com; Liu, Pu, E-mail: banbaokezhan@163.com; Li, Pengcheng, E-mail: lpcsdau@163.com; Wu, Changai, E-mail: cawu@sdau.edu.cn; Zheng, Chengchao, E-mail: cczheng@sdau.edu.cn; Huang, Jinguang, E-mail: jghuang@sdau.edu.cn

2014-11-28

Highlights: • It is the first time to investigate the biological function of AtLEA14 in salt stress response. • AtLEA14 enhances the salt stress tolerance both in Arabidopsis and yeast. • AtLEA14 responses to salt stress by stabilizing AtPP2-B11, an E3 ligase, under normal or salt stress conditions. - Abstract: Late embryogenesis abundant (LEA) proteins are implicated in various abiotic stresses in higher plants. In this study, we identified a LEA protein from Arabidopsis thaliana, AtLEA14, which was ubiquitously expressed in different tissues and remarkably induced with increased duration of salt treatment. Subcellular distribution analysis demonstrated that AtLEA14 was mainly localized in the cytoplasm. Transgenic Arabidopsis and yeast overexpressing AtLEA14 all exhibited enhanced tolerance to high salinity. The transcripts of salt stress-responsive marker genes (COR15a, KIN1, RD29B and ERD10) were overactivated in AtLEA14 overexpressing lines compared with those in wild type plants under normal or salt stress conditions. In vivo and in vitro analysis showed that AtLEA14 could effectively stabilize AtPP2-B11, an important E3 ligase. These results suggested that AtLEA14 had important protective functions under salt stress conditions in Arabidopsis.

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

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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.

Overexpression of CaTLP1, a putative transcription factor in chickpea (Cicer arietinum L.), promotes stress tolerance.

Science.gov (United States)

Wardhan, Vijay; Jahan, Kishwer; Gupta, Sonika; Chennareddy, Srinivasarao; Datta, Asis; Chakraborty, Subhra; Chakraborty, Niranjan

2012-07-01

Dehydration is the most crucial environmental constraint on plant growth and development, and agricultural productivity. To understand the underlying mechanism of stress tolerance, and to identify proteins for improving such important trait, we screened the dehydration-responsive proteome of chickpea and identified a tubby-like protein, referred to as CaTLP1. The CaTLP1 was found to predominantly bind to double-stranded DNA but incapable of transcriptional activation. We investigated the gene structure and organization and demonstrated, for the first time, that CaTLP1 may be involved in osmotic stress response in plants. The transcripts are strongly expressed in vegetative tissues but weakly in reproductive tissues. CaTLP1 is upregulated by dehydration and high salinity, and by treatment with abscisic acid (ABA), suggesting that its stress-responsive function might be associated with ABA-dependent network. Overexpression of CaTLP1 in transgenic tobacco plants conferred dehydration, salinity and oxidative stress tolerance along with improved shoot and root architecture. Molecular genetic analysis showed differential expression of CaTLP1 under normal and stress condition, and its preferential expression in the nucleus might be associated with enhanced stress tolerance. Our work suggests important roles of CaTLP1 in stress response as well as in the regulation of plant development.

Morphological characteristic of purple long yard bean cultivars and their tolerance to drought stress

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M W Lestari

2015-01-01

Full Text Available The cultivation of purple long yard bean which tolerance to drought stress and have high productivity can improve farming in arid area. The purpose of this study was to evaluate the mechanism of the tolerance purple long yard beans to drought stress based on morphologic characters, to get the hypothesis method of tolerance and to obtain tolerance cultivars to the drought stress. Eight cultivars of purple long yard beans, i.e. UBPHU1-41, UBPHU1-130, UBPU3-153, UBPU1-202, UBPU2-222, UBPU1-365, Brawijaya 4 and Bagong 2, were tested in two environmental conditions, 100% field capacity and 50% field capacity. The results showed that drought stress in purple long yard bean affected all morphological characters observed, except for root length and flowering time. Estimation of tolerance to drought stress using the Principles Component Analysis (PCA showed that the shoot fresh weight could be an indicator of purple pod bean tolerance to drought stress. However, the test using Stress Susceptibility Index (SSI was not able to classify the purple long yard bean tolerance to drought stress. The results of analysis using PCA followed by discriminant analysis and clustering dendrogram showed that the UBPU1-41, UBPU1-130, UBPU2-222, UBPU1-365, UB4 and Bagong 2 cultivars were medium cultivars that are tolerant to drought stress. Therefore, they can be planted in semiarid regions.

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

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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

Transformation of oats and its application to improving osmotic stress tolerance.

Science.gov (United States)

Maqbool, Shahina B; Zhong, Heng; Oraby, Hesham F; Sticklen, Mariam B

2009-01-01

Oat (Avena sativa L.), a worldwide temperate cereal crop, is deficient in tolerance to osmotic stress due to drought and/or salinity. To genetically transform the available commercial oat cultivars, a genotype-independent and efficient regeneration system from shoot apical meristems was developed using four oat cultivars: Prairie, Porter, Ogle, and Pacer. All these oat cultivars generated a genotype-independent in vitro differentiated multiple shoots from shoot apical meristems at a high frequency. Using this system, three oat cultivars were genetically co-transformed with pBY520 (containing hva1 and bar) and pAct1-D (containing gus) using biolistic trade mark bombardment. Transgenic plants were selected and regenerated using herbicide resistance and GUS as a marker. Molecular and biochemical analyses of putative transgenic plants confirmed the co-integration of hva1 and bar genes with a frequency of 100%, and 61.6% of the transgenic plants carried all three genes (hva1, bar and gus). Further analyses of R0, R1, and R2 progenies confirmed stable integration, expression, and Mendalian inheritance for all transgenes. Histochemical analysis of GUS protein in transgenic plants showed a high level of GUS expression in vascular tissues and in the pollen grains of mature flowers. Immunochemical analysis of transgenic plants indicated a constitutive expression of hva1 at all developmental stages. However, the level of HVA1 was higher during the early seedling stages. The characteristic of HVA1 expression for osmotic tolerance in transgenic oat progeny was analyzed in vitro as well as in vivo. Transgenic plants exhibited significantly (Pplants. The symptoms of wilting or death of leaves as observed in 80% of non-transgenic plants due to osmotic stress was delayed and detected only in less than 10% of trans-genic plants. These observations confirmed the characteristic of HVA1 protein as providing or enhancing the osmotic tolerance in transgenic plants against salinity and

Transgenic banana plants overexpressing a native plasma membrane aquaporin MusaPIP1;2 display high tolerance levels to different abiotic stresses.

Science.gov (United States)

Sreedharan, Shareena; Shekhawat, Upendra K S; Ganapathi, Thumballi R

2013-10-01

Water transport across cellular membranes is regulated by a family of water channel proteins known as aquaporins (AQPs). As most abiotic stresses like suboptimal temperatures, drought or salinity result in cellular dehydration, it is imperative to study the cause-effect relationship between AQPs and the cellular consequences of abiotic stress stimuli. Although plant cells have a high isoform diversity of AQPs, the individual and integrated roles of individual AQPs in optimal and suboptimal physiological conditions remain unclear. Herein, we have identified a plasma membrane intrinsic protein gene (MusaPIP1;2) from banana and characterized it by overexpression in transgenic banana plants. Cellular localization assay performed using MusaPIP1;2::GFP fusion protein indicated that MusaPIP1;2 translocated to plasma membrane in transformed banana cells. Transgenic banana plants overexpressing MusaPIP1;2 constitutively displayed better abiotic stress survival characteristics. The transgenic lines had lower malondialdehyde levels, elevated proline and relative water content and higher photosynthetic efficiency as compared to equivalent controls under different abiotic stress conditions. Greenhouse-maintained hardened transgenic plants showed faster recovery towards normal growth and development after cessation of abiotic stress stimuli, thereby underlining the importance of these plants in actual environmental conditions wherein the stress stimuli is often transient but severe. Further, transgenic plants where the overexpression of MusaPIP1;2 was made conditional by tagging it with a stress-inducible native dehydrin promoter also showed similar stress tolerance characteristics in in vitro and in vivo assays. Plants developed in this study could potentially enable banana cultivation in areas where adverse environmental conditions hitherto preclude commercial banana cultivation. © 2013 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons

Drought priming at vegetative growth stages improves tolerance to drought and heat stresses occurring during grain filling in spring wheat

DEFF Research Database (Denmark)

Wang, Xiao; Vignjevic, Marija; Liu, Fulai

2015-01-01

Plants of spring wheat (Triticum aestivum L. cv. Vinjett) were exposed to moderate water deficit at the vegetative growth stages six-leaf and/or stem elongation to investigate drought priming effects on tolerance to drought and heat stress events occurring during the grain filling stage. Compared......Plants of spring wheat (Triticum aestivum L. cv. Vinjett) were exposed to moderate water deficit at the vegetative growth stages six-leaf and/or stem elongation to investigate drought priming effects on tolerance to drought and heat stress events occurring during the grain filling stage...... of abscisic acid in primed plants under drought stress could contribute to higher grain yield compared to the non-primed plants. Taken together, the results indicate that drought priming during vegetative stages improved tolerance to both drought and heat stress events occurring during grain filling in wheat....

Study on Biodiesel plants growth performance and tolerance to ...

African Journals Online (AJOL)

Abstract. In this research, we studied the growth performance and tolerance of three biodiesel plants namely; Jatropha curcas, Moringa oleifera and Ricinus communis to water stress. Research conducted on the three different soils from Kaita, Jibiya and Mai'adua in the semi-desert environments of Katsina State, Nigeria.

Melatonin confers plant tolerance against cadmium stress via the decrease of cadmium accumulation and reestablishment of microRNA-mediated redox homeostasis.

Science.gov (United States)

Gu, Quan; Chen, Ziping; Yu, Xiuli; Cui, Weiti; Pan, Jincheng; Zhao, Gan; Xu, Sheng; Wang, Ren; Shen, Wenbiao

2017-08-01

Although melatonin-alleviated cadmium (Cd) toxicity both in animals and plants have been well studied, little is known about its regulatory mechanisms in plants. Here, we discovered that Cd stress stimulated the production of endogenous melatonin in alfalfa seedling root tissues. The pretreatment with exogenous melatonin not only increased melatonin content, but also alleviated Cd-induced seedling growth inhibition. The melatonin-rich transgenic Arabidopsis plants overexpressing alfalfa SNAT (a melatonin synthetic gene) exhibited more tolerance than wild-type plants under Cd conditions. Cd content was also reduced in root tissues. In comparison with Cd stress alone, ABC transporter and PCR2 transcripts in alfalfa seedlings, PDR8 and HMA4 in Arabidopsis, were up-regulated by melatonin. By contrast, Nramp6 transcripts were down-regulated. Changes in above transporters were correlated with the less accumulation of Cd. Additionally Cd-triggered redox imbalance was improved by melatonin. These could be supported by the changes of the Cu/Zn Superoxide Dismutase gene regulated by miR398a and miR398b. Histochemical staining, laser scanning confocal microscope, and H 2 O 2 contents analyses showed the similar tendencies. Taking together, we clearly suggested that melatonin enhanced Cd tolerance via decreasing cadmium accumulation and reestablishing the microRNAs-mediated redox homeostasis. Copyright © 2017 Elsevier B.V. All rights reserved.

Plant abiotic stress tolerance analysis in cauliflower using a curd micropropagation system

OpenAIRE

Rihan, HZ; Al-Issawi, M; Al-Shamari, M; Elmahrouk, M; Fuller, MP

2015-01-01

© 2015 ISHS. An effective protocol for cauliflower micropropagation was optimised and developed which enabled the production of tens of thousands of cauliflower microshoots from one cauliflower curd. The large number of microshoots that can be produced per culture unit facilitates the use of this protocol to analyse both the physiological and molecular components of abiotic stress tolerance. The protocol was used for cauliflower cold tolerance analysis and it was demonstrated that low tempera...

Variable Levels of Tolerance to Water Stress (Drought and Associated Biochemical Markers in Tunisian Barley Landraces

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Sameh Dbira

2018-03-01

Full Text Available Due to its high tolerance to abiotic stress, barley (Hordeum vulgare is cultivated in many arid areas of the world. In the present study, we evaluate the tolerance to water stress (drought in nine accessions of “Ardhaoui” barley landraces from different regions of Tunisia. The genetic diversity of the accessions is evaluated with six SSR markers. Seedlings from the nine accessions are subjected to water stress by completely stopping irrigation for three weeks. A high genetic diversity is detected among the nine accessions, with no relationships between genetic distance and geographical or ecogeographical zone. The analysis of growth parameters and biochemical markers in the water stress-treated plants in comparison to their respective controls indicated great variability among the studied accessions. Accession 2, from El May Island, displayed high tolerance to drought. Increased amounts of proline in water-stressed plants could not be correlated with a better response to drought, as the most tolerant accessions contained lower levels of this osmolyte. A good correlation was established between the reduction of growth and degradation of chlorophylls and increased levels of malondialdehyde and total phenolics. These biochemical markers may be useful for identifying drought tolerant materials in barley.

Role of phytosterols in drought stress tolerance in rice.

Science.gov (United States)

Kumar, M S Sujith; Ali, Kishwar; Dahuja, Anil; Tyagi, Aruna

2015-11-01

Phytosterols are integral components of the membrane lipid bilayer in plants. They regulate membrane fluidity to influence its properties, functions and structure. An increase in accumulation of phytosterols namely campesterol, stigmasterol and β-sitosterol was observed in rice as seedlings matured. The levels of the major phytosterol, β-sitosterol in N22 (drought tolerant) rice seedlings was found to increase proportionately with severity of drought stress. Its levels were 145, 216, 345 and 364 μg/g FW after subjecting to water stress for 3, 6, 9 and 12 days respectively, while for IR64 (drought susceptible), levels were 137, 198, 227 and 287 μg/g FW at the same stages. Phytosterols were also found to increase with maturity as observed at 30, 50 and 75 days after planting. The activity of HMG-CoA reductase (EC 1.1.1.34) which is considered to be a key limiting enzyme in the biosynthesis of phytosterols was 0.55, 0.56, 0.78 and 0.85 μmol/min/L at 3, 6, 9 and 12 days of water stress in N22 and 0.31, 0.50, 0.54 and 0.65 μmol/min/L in case of IR64 respectively. The elevation in the levels of phytosterols as well as the activity of HMG-CoA reductase during drought stress indicates the role of phytosterols in providing tolerance to stress. Copyright © 2015. Published by Elsevier Masson SAS.

Evaluation of Drought response in Some Rice Mutant Lines Using Stress Tolerance Indices

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H Aminpanah

2018-05-01

Full Text Available Introduction Drought is a major problem that limits the adoption of high-yielding rice varieties in drought-prone rainfed rice environments. To improve crop productivity, it is necessary to understand the mechanism of plant responses to drought conditions with the ultimate goal of improving crop performance in the vast areas of the world where rainfall is limiting or unreliable. Safaei Chaeikar et al. (2008 reported that MP, GMP, HM and STI indices, which showed the highest correlation with grain yield under both optimal and stress conditions, can be used as the best indices to introduce drought-tolerant genotypes in rice breeding programs. They also were introduced Nemat, Sepidrood, IR64, IR50 and Bejar genotypes as tolerant varieties. The present study was conducted to determine how drought affects grain yield in rice mutant lines and also to test this hypothesis in order to identify the most suitable indices/genotypes. Materials and Methods A field trial was conducted at Iranian Rice Research Centers in North of Iran, Rasht (latitude 37◦28', longitude 49◦28'E and altitude 7m below the sea level, during the 2014-2015 growing season. The seeds were sown in a nursery on the 10 May and 25 day old seedlings were transplanted to the field. Two separately experiment was carried out under reproductive stage drought stress and controlled conditions based on randomized complete block design with three replications, in four-row plots of three m length. Transplanting was done using 1 seedling per hill; at hill spacing of 25 cm × 25 cm. 18 rice genotypes were consisted 14 M5 mutant lines and their four parental cultivars. Results and Discussion Analysis of variance indicated significant effects of drought stress, genotype and interaction effects of two factors on grain yield, plant height, flag leaf area, tiller number and grain fertility percentage. Drought stress at reproductive stage caused reduction in grain yield (59.47%, grain fertility

Complete Genome Sequence Analysis of Enterobacter sp. SA187, a Plant Multi-Stress Tolerance Promoting Endophytic Bacterium

KAUST Repository

Andres-Barrao, Cristina; Lafi, Feras Fawzi; Alam, Intikhab; Zé licourt, Axel de; Eida, Abdul Aziz; Bokhari, Ameerah; Alzubaidy, Hanin S.; Bajic, Vladimir B.; Hirt, Heribert; Saad, Maged

2017-01-01

Enterobacter sp. SA187 is an endophytic bacterium that has been isolated from root nodules of the indigenous desert plant Indigofera argentea. SA187 could survive in the rhizosphere as well as in association with different plant species, and was able to provide abiotic stress tolerance to Arabidopsis thaliana. The genome sequence of SA187 was obtained by using Pacific BioScience (PacBio) single-molecule sequencing technology, with average coverage of 275X. The genome of SA187 consists of one single 4,429,597 bp chromosome, with an average 56% GC content and 4,347 predicted protein coding DNA sequences (CDS), 153 ncRNA, 7 rRNA, and 84 tRNA. Functional analysis of the SA187 genome revealed a large number of genes involved in uptake and exchange of nutrients, chemotaxis, mobilization and plant colonization. A high number of genes were also found to be involved in survival, defense against oxidative stress and production of antimicrobial compounds and toxins. Moreover, different metabolic pathways were identified that potentially contribute to plant growth promotion. The information encoded in the genome of SA187 reveals the characteristics of a dualistic lifestyle of a bacterium that can adapt to different environments and promote the growth of plants. This information provides a better understanding of the mechanisms involved in plant-microbe interaction and could be further exploited to develop SA187 as a biological agent to improve agricultural practices in marginal and arid lands.

Complete Genome Sequence Analysis of Enterobacter sp. SA187, a Plant Multi-Stress Tolerance Promoting Endophytic Bacterium

KAUST Repository

Andres-Barrao, Cristina

2017-10-20

Enterobacter sp. SA187 is an endophytic bacterium that has been isolated from root nodules of the indigenous desert plant Indigofera argentea. SA187 could survive in the rhizosphere as well as in association with different plant species, and was able to provide abiotic stress tolerance to Arabidopsis thaliana. The genome sequence of SA187 was obtained by using Pacific BioScience (PacBio) single-molecule sequencing technology, with average coverage of 275X. The genome of SA187 consists of one single 4,429,597 bp chromosome, with an average 56% GC content and 4,347 predicted protein coding DNA sequences (CDS), 153 ncRNA, 7 rRNA, and 84 tRNA. Functional analysis of the SA187 genome revealed a large number of genes involved in uptake and exchange of nutrients, chemotaxis, mobilization and plant colonization. A high number of genes were also found to be involved in survival, defense against oxidative stress and production of antimicrobial compounds and toxins. Moreover, different metabolic pathways were identified that potentially contribute to plant growth promotion. The information encoded in the genome of SA187 reveals the characteristics of a dualistic lifestyle of a bacterium that can adapt to different environments and promote the growth of plants. This information provides a better understanding of the mechanisms involved in plant-microbe interaction and could be further exploited to develop SA187 as a biological agent to improve agricultural practices in marginal and arid lands.

Recent Molecular Advances on Downstream Plant Responses to Abiotic Stress

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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.

What molecular mechanism is adapted by plants during salt stress ...

African Journals Online (AJOL)

What molecular mechanism is adapted by plants during salt stress tolerance? ... Salt stress harmfully shocks agricultural yield throughout the world affecting production whether it is for subsistence or economic outcomes. ... from 32 Countries:.

A Benzimidazole Proton Pump Inhibitor Increases Growth and Tolerance to Salt Stress in Tomato

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Michael J. Van Oosten

2017-07-01

Full Text Available Pre-treatment of tomato plants with micromolar concentrations of omeprazole (OP, a benzimidazole proton pump inhibitor in mammalian systems, improves plant growth in terms of fresh weight of shoot and roots by 49 and 55% and dry weight by 54 and 105% under salt stress conditions (200 mM NaCl, respectively. Assessment of gas exchange, ion distribution, and gene expression profile in different organs strongly indicates that OP interferes with key components of the stress adaptation machinery, including hormonal control of root development (improving length and branching, protection of the photosynthetic system (improving quantum yield of photosystem II and regulation of ion homeostasis (improving the K+:Na+ ratio in leaves and roots. To our knowledge OP is one of the few known molecules that at micromolar concentrations manifests a dual function as growth enhancer and salt stress protectant. Therefore, OP can be used as new inducer of stress tolerance to better understand molecular and physiological stress adaptation paths in plants and to design new products to improve crop performance under suboptimal growth conditions.Highlight: Omeprazole enhances growth of tomato and increases tolerance to salinity stress through alterations of gene expression and ion uptake and transport.

Modulation of Antioxidant Defense System Is Associated with Combined Drought and Heat Stress Tolerance in Citrus.

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Zandalinas, Sara I; Balfagón, Damián; Arbona, Vicent; Gómez-Cadenas, Aurelio

2017-01-01

Drought and high temperatures are two major abiotic stress factors that often occur simultaneously in nature, affecting negatively crop performance and yield. Moreover, these environmental challenges induce oxidative stress in plants through the production of reactive oxygen species (ROS). Carrizo citrange and Cleopatra mandarin are two citrus genotypes with contrasting ability to cope with the combination of drought and heat stress. In this work, a direct relationship between an increased antioxidant activity and stress tolerance is reported. According to our results, the ability of Carrizo plants to efficiently coordinate superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and glutathione reductase (GR) activities involved in ROS detoxification along with the maintenance of a favorable GSH/GSSG ratio could be related to their relative tolerance to this stress combination. On the other hand, the increment of SOD activity and the inefficient GR activation along with the lack of CAT and APX activities in Cleopatra plants in response to the combination of drought and heat stress, could contribute to an increased oxidative stress and the higher sensibility of this citrus genotype to this stress combination.

The Cotton WRKY Gene GhWRKY41 Positively Regulates Salt and Drought Stress Tolerance in Transgenic Nicotiana benthamiana.

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Xiaoqian Chu

Full Text Available WRKY transcription factors constitute a very large family of proteins in plants and participate in modulating plant biological processes, such as growth, development and stress responses. However, the exact roles of WRKY proteins are unclear, particularly in non-model plants. In this study, Gossypium hirsutum WRKY41 (GhWRKY41 was isolated and transformed into Nicotiana benthamiana. Our results showed that overexpression of GhWRKY41 enhanced the drought and salt stress tolerance of transgenic Nicotiana benthamiana. The transgenic plants exhibited lower malondialdehyde content and higher antioxidant enzyme activity, and the expression of antioxidant genes was upregulated in transgenic plants exposed to osmotic stress. A β-glucuronidase (GUS staining assay showed that GhWRKY41 was highly expressed in the stomata when plants were exposed to osmotic stress, and plants overexpressing GhWRKY41 exhibited enhanced stomatal closure when they were exposed to osmotic stress. Taken together, our findings demonstrate that GhWRKY41 may enhance plant tolerance to stress by functioning as a positive regulator of stoma closure and by regulating reactive oxygen species (ROS scavenging and the expression of antioxidant genes.

Constitutive expression of DaCBF7, an Antarctic vascular plant Deschampsia antarctica CBF homolog, resulted in improved cold tolerance in transgenic rice plants.

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Byun, Mi Young; Lee, Jungeun; Cui, Li Hua; Kang, Yoonjee; Oh, Tae Kyung; Park, Hyun; Lee, Hyoungseok; Kim, Woo Taek

2015-07-01

Deschampsia antarctica is an Antarctic hairgrass that grows on the west coast of the Antarctic peninsula. In this report, we have identified and characterized a transcription factor, D. antarctica C-repeat binding factor 7 (DaCBF7), that is a member of the monocot group V CBF homologs. The protein contains a single AP2 domain, a putative nuclear localization signal, and the typical CBF signature. DaCBF7, like other monocot group V homologs, contains a distinct polypeptide stretch composed of 43 amino acids in front of the AP2 motif. DaCBF7 was predominantly localized to nuclei and interacted with the C-repeat/dehydration responsive element (CRT/DRE) core sequence (ACCGAC) in vitro. DaCBF7 was induced by abiotic stresses, including drought, cold, and salinity. To investigate its possible cellular role in cold tolerance, a transgenic rice system was employed. DaCBF7-overexpressing transgenic rice plants (Ubi:DaCBF7) exhibited markedly increased tolerance to cold stress compared to wild-type plants without growth defects; however, overexpression of DaCBF7 exerted little effect on tolerance to drought or salt stress. Transcriptome analysis of a Ubi:DaCBF7 transgenic line revealed 13 genes that were up-regulated in DaCBF7-overexpressing plants compared to wild-type plants in the absence of cold stress and in short- or long-term cold stress. Five of these genes, dehydrin, remorin, Os03g63870, Os11g34790, and Os10g22630, contained putative CRT/DRE or low-temperature responsive elements in their promoter regions. These results suggest that overexpression of DaCBF7 directly and indirectly induces diverse genes in transgenic rice plants and confers enhanced tolerance to cold stress. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Overexpression of EcbHLH57 Transcription Factor from Eleusine coracana L. in Tobacco Confers Tolerance to Salt, Oxidative and Drought Stress.

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K C Babitha

Full Text Available Basic helix-loop-helix (bHLH transcription factors constitute one of the largest families in plants and are known to be involved in various developmental processes and stress tolerance. We report the characterization of a stress responsive bHLH transcription factor from stress adapted species finger millet which is homologous to OsbHLH57 and designated as EcbHLH57. The full length sequence of EcbHLH57 consisted of 256 amino acids with a conserved bHLH domain followed by leucine repeats. In finger millet, EcbHLH57 transcripts were induced by ABA, NaCl, PEG, methyl viologen (MV treatments and drought stress. Overexpression of EcbHLH57 in tobacco significantly increased the tolerance to salinity and drought stress with improved root growth. Transgenic plants showed higher photosynthetic rate and stomatal conductance under drought stress that resulted in higher biomass. Under long-term salinity stress, the transgenic plants accumulated higher seed weight/pod and pod number. The transgenic plants were also tolerant to oxidative stress and showed less accumulation of H202 and MDA levels. The overexpression of EcbHLH57 enhanced the expression of stress responsive genes such as LEA14, rd29A, rd29B, SOD, APX, ADH1, HSP70 and also PP2C and hence improved tolerance to diverse stresses.

Evidence for nuclear interaction of a cytoskeleton protein (OsIFL) with metallothionein and its role in salinity stress tolerance

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Soda, Neelam; Sharan, Ashutosh; Gupta, Brijesh K.; Singla-Pareek, Sneh L.; Pareek, Ashwani

2016-01-01

Soil salinity is being perceived as a major threat to agriculture. Plant breeders and molecular biologist are putting their best efforts to raise salt-tolerant crops. The discovery of the Saltol QTL, a major QTL localized on chromosome I, responsible for salt tolerance at seedling stage in rice has given new hopes for raising salinity tolerant rice genotypes. In the present study, we have functionally characterized a Saltol QTL localized cytoskeletal protein, intermediate filament like protein (OsIFL), of rice. Studies related to intermediate filaments are emerging in plants, especially with respect to their involvement in abiotic stress response. Our investigations clearly establish that the heterologous expression of OsIFL in three diverse organisms (bacteria, yeast and tobacco) provides survival advantage towards diverse abiotic stresses. Screening of rice cDNA library revealed OsIFL to be strongly interacting with metallothionein protein. Bimolecular fluorescence complementation assay further confirmed this interaction to be occurring inside the nucleus. Overexpression of OsIFL in transgenic tobacco plants conferred salinity stress tolerance by maintaining favourable K+/Na+ ratio and thus showed protection from salinity stress induced ion toxicity. This study provides the first evidence for the involvement of a cytoskeletal protein in salinity stress tolerance in diverse organisms. PMID:27708383

Grafting improves cucumber water stress tolerance in Saudi Arabia.

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Al-Harbi, Abdulaziz R; Al-Omran, Abdulrasoul M; Alharbi, Khadiga

2018-02-01

Water scarcity is a major limiting factor for crop productivity in arid and semi-arid areas. Grafting elite commercial cultivars onto selected vigorous rootstocks is considered as a useful strategy to alleviate the impact of environmental stresses. This study aims to investigate the feasibility of using grafting to improve fruit yield and quality of cucumber under water stress conditions. Alosama F 1 cucumber cultivar ( Cucumis sativus L.) was grafted onto Affyne ( Cucumis sativus L.) and Shintoza A90 ( Cucurbitamaxima × C. moschata ) rootstocks. Non-grafted plants were used as control. All genotypes were grown under three surface drip irrigation regimes: 50%, 75% and 100% of the crop evapotranspiration (ETc), which represent high-water stress, moderate-water stress and non-water stress conditions, respectively. Yield and fruit quality traits were analyzed and assessed. In comparison to the non-grafted plants, the best grafting treatment under water stress was Alosama F 1 grafted onto Shintoza A90 rootstock. It had an overall improved yield and fruit quality under water stress owing to an increase in the total fruit yield by 27%, from 4.815 kg plant -1 in non-grafted treatment to 6.149 kg plant -1 in grafted treatment under moderate -water stress, total soluble solid contents (13%), titratable acidity (39%) and vitamin C (33%). The soil water contents were low in soil surface and increase gradually with soil depth, while salt distribution showed an adverse trend. The positive effects of grafting on plant growth, productivity, and water use efficiency support this strategy as an useful tool for improving water stress tolerance in greenhouse grown cucumber in Saudi Arabia.

Role of abscisic acid in strigolactone-induced salt stress tolerance in arbuscular mycorrhizal Sesbania cannabina seedlings.

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Ren, Cheng-Gang; Kong, Cun-Cui; Xie, Zhi-Hong

2018-05-03

Strigolactones (SLs) are considered to be a novel class of phytohormone involved in plant defense responses. Currently, their relationships with other plant hormones, such as abscisic acid (ABA), during responses to salinity stress are largely unknown. In this study, the relationship between SL and ABA during the induction of H 2 O 2 - mediated tolerance to salt stress were studied in arbuscular mycorrhizal (AM) Sesbania cannabina seedlings. The SL levels increased after ABA treatments and decreased when ABA biosynthesis was inhibited in AM plants. Additionally, the expression levels of SL-biosynthesis genes in AM plants increased following treatments with exogenous ABA and H 2 O 2 . Furthermore, ABA-induced SL production was blocked by a pre-treatment with dimethylthiourea, which scavenges H 2 O 2 . In contrast, ABA production was unaffected by dimethylthiourea. Abscisic acid induced only partial and transient increases in the salt tolerance of TIS108 (a SL synthesis inhibitor) treated AM plants, whereas SL induced considerable and prolonged increases in salt tolerance after a pre-treatment with tungstate. These results strongly suggest that ABA is regulating the induction of salt tolerance by SL in AM S. cannabina seedlings.

Microbial stress tolerance for biofuels. Systems biology

Energy Technology Data Exchange (ETDEWEB)

Liu, Zonglin Lewis (ed.) [National Center for Agricultural Utilization Research, USDA-ARS, Peoria, IL (United States)

2012-07-01

The development of sustainable and renewable biofuels is attracting growing interest. It is vital to develop robust microbial strains for biocatalysts that are able to function under multiple stress conditions. This Microbiology Monograph provides an overview of methods for studying microbial stress tolerance for biofuels applications using a systems biology approach. Topics covered range from mechanisms to methodology for yeast and bacteria, including the genomics of yeast tolerance and detoxification; genetics and regulation of glycogen and trehalose metabolism; programmed cell death; high gravity fermentations; ethanol tolerance; improving biomass sugar utilization by engineered Saccharomyces; the genomics on tolerance of Zymomonas mobilis; microbial solvent tolerance; control of stress tolerance in bacterial host organisms; metabolomics for ethanologenic yeast; automated proteomics work cell systems for strain improvement; and unification of gene expression data for comparable analyses under stress conditions. (orig.)

Plant Abiotic Stress Proteomics: The Major Factors Determining Alterations in Cellular Proteome

Science.gov (United States)

Kosová, Klára; Vítámvás, Pavel; Urban, Milan O.; Prášil, Ilja T.; Renaut, Jenny

2018-01-01

HIGHLIGHTS: Major environmental and genetic factors determining stress-related protein abundance are discussed.Major aspects of protein biological function including protein isoforms and PTMs, cellular localization and protein interactions are discussed.Functional diversity of protein isoforms and PTMs is discussed. Abiotic stresses reveal profound impacts on plant proteomes including alterations in protein relative abundance, cellular localization, post-transcriptional and post-translational modifications (PTMs), protein interactions with other protein partners, and, finally, protein biological functions. The main aim of the present review is to discuss the major factors determining stress-related protein accumulation and their final biological functions. A dynamics of stress response including stress acclimation to altered ambient conditions and recovery after the stress treatment is discussed. The results of proteomic studies aimed at a comparison of stress response in plant genotypes differing in stress adaptability reveal constitutively enhanced levels of several stress-related proteins (protective proteins, chaperones, ROS scavenging- and detoxification-related enzymes) in the tolerant genotypes with respect to the susceptible ones. Tolerant genotypes can efficiently adjust energy metabolism to enhanced needs during stress acclimation. Stress tolerance vs. stress susceptibility are relative terms which can reflect different stress-coping strategies depending on the given stress treatment. The role of differential protein isoforms and PTMs with respect to their biological functions in different physiological constraints (cellular compartments and interacting partners) is discussed. The importance of protein functional studies following high-throughput proteome analyses is presented in a broader context of plant biology. In summary, the manuscript tries to provide an overview of the major factors which have to be considered when interpreting data from proteomic

Overexpression of WsSGTL1 Gene of Withania somnifera Enhances Salt Tolerance, Heat Tolerance and Cold Acclimation Ability in Transgenic Arabidopsis Plants

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Mishra, Manoj K.; Chaturvedi, Pankaj; Singh, Ruchi; Singh, Gaurav; Sharma, Lokendra K.; Pandey, Vibha; Kumari, Nishi; Misra, Pratibha

2013-01-01

Background Sterol glycosyltrnasferases (SGT) are enzymes that glycosylate sterols which play important role in plant adaptation to stress and are medicinally important in plants like Withania somnifera. The present study aims to find the role of WsSGTL1 which is a sterol glycosyltransferase from W. somnifera, in plant’s adaptation to abiotic stress. Methodology The WsSGTL1 gene was transformed in Arabidopsis thaliana through Agrobacterium mediated transformation, using the binary vector pBI121, by floral dip method. The phenotypic and physiological parameters like germination, root length, shoot weight, relative electrolyte conductivity, MDA content, SOD levels, relative electrolyte leakage and chlorophyll measurements were compared between transgenic and wild type Arabidopsis plants under different abiotic stresses - salt, heat and cold. Biochemical analysis was done by HPLC-TLC and radiolabelled enzyme assay. The promoter of the WsSGTL1 gene was cloned by using Genome Walker kit (Clontech, USA) and the 3D structures were predicted by using Discovery Studio Ver. 2.5. Results The WsSGTL1 transgenic plants were confirmed to be single copy by Southern and homozygous by segregation analysis. As compared to WT, the transgenic plants showed better germination, salt tolerance, heat and cold tolerance. The level of the transgene WsSGTL1 was elevated in heat, cold and salt stress along with other marker genes such as HSP70, HSP90, RD29, SOS3 and LEA4-5. Biochemical analysis showed the formation of sterol glycosides and increase in enzyme activity. When the promoter of WsSGTL1 gene was cloned from W. somnifera and sequenced, it contained stress responsive elements. Bioinformatics analysis of the 3D structure of the WsSGTL1 protein showed functional similarity with sterol glycosyltransferase AtSGT of A. thaliana. Conclusions Transformation of WsSGTL1 gene in A. thaliana conferred abiotic stress tolerance. The promoter of the gene in W.somnifera was found to have stress

Overexpression of Nictaba-Like Lectin Genes from Glycine max Confers Tolerance towards Pseudomonas syringae Infection, Aphid Infestation and Salt Stress in Transgenic Arabidopsis Plants

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Sofie Van Holle

2016-10-01

Full Text Available Plants have evolved a sophisticated immune system that allows them to recognize invading pathogens by specialized receptors. Carbohydrate-binding proteins or lectins are part of this immune system and especially the lectins that reside in the nucleocytoplasmic compartment are known to be implicated in biotic and abiotic stress responses. The class of Nictaba-like lectins (NLL groups all proteins with homology to the tobacco (Nicotiana tabacum lectin, known as a stress-inducible lectin. Here we focus on two Nictaba homologs from soybean (Glycine max, referred to as GmNLL1 and GmNLL2. Confocal laser scanning microscopy of fusion constructs with the green fluorescent protein either transiently expressed in Nicotiana benthamiana leaves or stably transformed in tobacco BY-2 suspension cells revealed a nucleocytoplasmic localization for the GmNLLs under study. RT-qPCR analysis of the transcript levels for the Nictaba-like lectins in soybean demonstrated that the genes are expressed in several tissues throughout the development of the plant. Furthermore, it was shown that salt treatment, Phytophthora sojae infection and Aphis glycines infestation trigger the expression of particular NLL genes. Stress experiments with Arabidopsis lines overexpressing the NLLs from soybean yielded an enhanced tolerance of the plant towards bacterial infection (Pseudomonas syringae, insect infestation (Myzus persicae and salinity. Our data showed a better performance of the transgenic lines compared to wild type plants, indicating that the NLLs from soybean are implicated in the stress response. These data can help to further elucidate the physiological importance of the Nictaba-like lectins from soybean, which can ultimately lead to the design of crop plants with a better tolerance to changing environmental conditions.

Increased resistance to a generalist herbivore in a salinity-stressed non-halophytic plant.

Science.gov (United States)

Renault, Sylvie; Wolfe, Scott; Markham, John; Avila-Sakar, Germán

2016-01-01

Plants often grow under the combined stress of several factors. Salinity and herbivory, separately, can severely hinder plant growth and reproduction, but the combined effects of both factors are still not clearly understood. Salinity is known to reduce plant tissue nitrogen content and growth rates. Since herbivores prefer tissues with high N content, and biochemical pathways leading to resistance are commonly elicited by salt-stress, we hypothesized that plants growing in saline conditions would have enhanced resistance against herbivores. The non-halophyte, Brassica juncea, and the generalist herbivore Trichoplusia ni were used to test the prediction that plants subjected to salinity stress would be both more resistant and more tolerant to herbivory than those growing without salt stress. Plants were grown under different NaCl levels, and either exposed to herbivores and followed by removal of half of their leaves, or left intact. Plants were left to grow and reproduce until senescence. Tissue quality was assessed, seeds were counted and biomass of different organs measured. Plants exposed to salinity grew less, had reduced tissue nitrogen, protein and chlorophyll content, although proline levels increased. Specific leaf area, leaf water content, transpiration and root:shoot ratio remained unaffected. Plants growing under saline condition had greater constitutive resistance than unstressed plants. However, induced resistance and tolerance were not affected by salinity. These results support the hypothesis that plants growing under salt-stress are better defended against herbivores, although in B. juncea this may be mostly through resistance, and less through tolerance. Published by Oxford University Press on behalf of the Annals of Botany Company.

Plant Growth Promoting Rhizobacteria in Amelioration of Salinity Stress: A Systems Biology Perspective

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Gayathri Ilangumaran

2017-10-01

Full Text Available Salinity affects plant growth and is a major abiotic stress that limits crop productivity. It is well-understood that environmental adaptations and genetic traits regulate salinity tolerance in plants, but imparting the knowledge gained towards crop improvement remain arduous. Harnessing the potential of beneficial microorganisms present in the rhizosphere is an alternative strategy for improving plant stress tolerance. This review intends to elucidate the understanding of salinity tolerance mechanisms attributed by plant growth promoting rhizobacteria (PGPR. Recent advances in molecular studies have yielded insights into the signaling networks of plant–microbe interactions that contribute to salt tolerance. The beneficial effects of PGPR involve boosting key physiological processes, including water and nutrient uptake, photosynthesis, and source-sink relationships that promote growth and development. The regulation of osmotic balance and ion homeostasis by PGPR are conducted through modulation of phytohormone status, gene expression, protein function, and metabolite synthesis in plants. As a result, improved antioxidant activity, osmolyte accumulation, proton transport machinery, salt compartmentalization, and nutrient status reduce osmotic stress and ion toxicity. Furthermore, in addition to indole-3-acetic acid and 1-aminocyclopropane-1-carboxylic acid deaminase biosynthesis, other extracellular secretions of the rhizobacteria function as signaling molecules and elicit stress responsive pathways. Application of PGPR inoculants is a promising measure to combat salinity in agricultural fields, thereby increasing global food production.

Ectopic over-expression of peroxisomal ascorbate peroxidase (SbpAPX) gene confers salt stress tolerance in transgenic peanut (Arachis hypogaea).

Science.gov (United States)

Singh, Natwar; Mishra, Avinash; Jha, Bhavanath

2014-08-15

Peroxisomal ascorbate peroxidase gene (SbpAPX) of an extreme halophyte Salicornia brachiata imparts abiotic stress endurance and plays a key role in the protection against oxidative stress. The cloned SbpAPX gene was transformed to local variety of peanut and about 100 transgenic plants were developed using optimized in vitro regeneration and Agrobacterium mediated genetic transformation method. The T0 transgenic plants were confirmed for the gene integration; grown under controlled condition in containment green house facility; seeds were harvested and T1 plants were raised. Transgenic plants (T1) were further confirmed by PCR using gene specific primers and histochemical GUS assay. About 40 transgenic plants (T1) were selected randomly and subjected for salt stress tolerance study. Transgenic plants remained green however non-transgenic plants showed bleaching and yellowish leaves under salt stress conditions. Under stress condition, transgenic plants continued normal growth and completed their life cycle. Transgenic peanut plants exhibited adequate tolerance under salt stress condition and thus could be explored for the cultivation in salt affected areas for the sustainable agriculture. Copyright © 2014 Elsevier B.V. All rights reserved.

24-Epibrassinoslide enhances plant tolerance to stress from low temperatures and poor light intensities in tomato (Lycopersicon esculentum Mill.).

Science.gov (United States)

Cui, Lirong; Zou, Zhirong; Zhang, Jing; Zhao, Yanyan; Yan, Fei

2016-01-01

Brassinosteroids (Brs) are a newly recognized group of active steroidal hormones that occur at low concentrations in all plant parts and one of the active and stable forms is 24-epibrassinolide (EBR). We investigated the effect of EBR on tomato (Lycopersicon esculentum Mill.) and its mechanism when seedlings were exposed to low temperature and poor light stress conditions. Leaves of stress-tolerant 'Zhongza9' and stress-sensitive 'Zhongshu4' cultivars were pre-treated with spray solutions containing either 0.1 μM EBR or no EBR (control). The plants were then transferred to chambers where they were exposed to low temperatures of 12 °C/6 °C (day/night) under a low light (LL) level of 80 μmol · m(-2) · s(-1). Exogenous application of EBR significantly increased the antioxidant activity of superoxide dismutase, catalase and peroxidase, and decreased the rate of O2 · (-) formation and H2O2 and malondialdehyde contents. Additionally, the ATP synthase β subunit content was increased by exogenous hormone application. Based on these results, we conclude that exogenous EBR can elicit synergism between the antioxidant enzyme systems and the ATP synthase β subunit so that scavenging of reactive oxygen species becomes more efficient. These activities enable plants to cope better under combined low temperature and poor light stresses.

New Insights on plant salt tolerance mechanisms and their potential use for breeding

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Moez HANIN

2016-11-01

Full Text Available Soil salinization is a major threat to agriculture in arid and semi-arid regions, where water scarcity and inadequate drainage of irrigated lands severely reduce crop yield. Salt accumulation inhibits plant growth and reduces the ability to uptake water and nutrients, leading to osmotic or water-deficit stress. Salt is also causing injury of the young photosynthetic leaves and acceleration of their senescence, as the Na+ cation is toxic when accumulating in cell cytosol resulting in ionic imbalance and toxicity of transpiring leaves. To cope with salt stress, plants have evolved mainly two types of tolerance mechanisms based on either limiting the entry of salt by the roots, or controlling its concentration and distribution. Understanding the overall control of Na+ accumulation and functional studies of genes involved in transport processes, will provide a new opportunity to improve the salinity tolerance of plants relevant to food security in arid regions. A better understanding of these tolerance mechanisms can be used to breed crops with improved yield performance under salinity stress. Moreover, associations of cultures with nitrogen-fixing bactéria and arbuscular mycorrhizal fungi could serve as an alternative and sustainable strategy to increase crop yields in salt affected fields.

Improved stress tolerance and productivity in transgenic rice plants constitutively expressing the Oryza sativa glutathione synthetase OsGS under paddy field conditions.

Science.gov (United States)

Park, Seong-Im; Kim, Young-Saeng; Kim, Jin-Ju; Mok, Ji-Eun; Kim, Yul-Ho; Park, Hyang-Mi; Kim, Il-Sup; Yoon, Ho-Sung

2017-08-01

Reactive oxygen species, which increase under various environmental stresses, have deleterious effects on plants. An important antioxidant, glutathione, is used to detoxify reactive oxygen species in plant cells and is mainly produced by two enzymes: gamma-glutamylcysteine synthetase (γ-ECS) and glutathione synthetase (GS). To evaluate the functional roles of the glutathione synthetase gene (OsGS) in rice, we generated four independent transgenic rice plants (TG1-TG4) that overexpressed OsGS under the control of the constitutively expressed OsCc1 promoter. When grown under natural paddy field conditions, the TG rice plants exhibited greater growth development, higher chlorophyll content, and higher GSH/GSSH ratios than control wild-type (WT) rice plants. Subsequently, the TG rice plants enhanced redox homeostasis by preventing hydroperoxide-mediated membrane damage, which improved their adaptation to environmental stresses. As a result, TG rice plants improved rice grain yield and total biomass following increases in panicle number and number of spikelets per panicle, despite differences in climate during the cultivation periods of 2014 and 2015. Overall, our results indicate that OsGS overexpression improved redox homeostasis by enhancing the glutathione pool, which resulted in greater tolerance to environmental stresses in the paddy fields. Copyright © 2017. Published by Elsevier GmbH.

The Grape VlWRKY3 Gene Promotes Abiotic and Biotic Stress Tolerance in Transgenic Arabidopsis thaliana

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Rongrong Guo

2018-04-01

Full Text Available WRKY transcription factors are known to play important roles in plant responses to various abiotic and biotic stresses. The grape WRKY gene, WRKY3 was previously reported to respond to salt and drought stress, as well as methyl jasmonate and ethylene treatments in Vitis labrusca × V. vinifera cv. ‘Kyoho.’ In the current study, WRKY3 from the ‘Kyoho’ grape cultivar was constitutively expressed in Arabidopsis thaliana under control of the cauliflower mosaic virus 35S promoter. The 35S::VlWRKY3 transgenic A. thaliana plants showed improved salt and drought stress tolerance during the germination, seedling and the mature plant stages. Various physiological traits related to abiotic stress responses were evaluated to gain further insight into the role of VlWRKY3, and it was found that abiotic stress caused less damage to the transgenic seedlings than to the wild-type (WT plants. VlWRKY3 over-expression also resulted in altered expression levels of abiotic stress-responsive genes. Moreover, the 35S::VlWRKY3 transgenic A. thaliana lines showed improved resistance to Golovinomyces cichoracearum, but increased susceptibility to Botrytis cinerea, compared with the WT plants. Collectively, these results indicate that VlWRKY3 plays important roles in responses to both abiotic and biotic stress, and modification of its expression may represent a strategy to enhance stress tolerance in crops.

Role Of Ascorbic Acid In Imparting Tolerance To Plants Against Oxidizing Pollutants

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Priyanka Sharma

2015-08-01

Full Text Available Ascorbic acid is an antioxidant in plants which play important role in activation of many physiological and defense mechanisms. The level of ascorbic acid in plants is determinant of its tolerance against the adverse effect of oxidizing pollutants. The present study tries to relate the variation in ascorbic acid content with the tolerance and sensitivity of two selected plant species viz. Azadirachtaindica and Pongamiapinnata by calculating their Air Pollution Tolerance Index APTI during winter season from November to March in the urban city Delhi of North India. Moreover ascorbic acid is also an important part of chloroplast it protects different components of photosynthetic system from oxidative stress. Thus to understand the role of ascorbic acid in imparting tolerance to plants against oxidizing pollutants the changes in chlorophyll content of the selected plant species with variation in ambient ozone concentration was analysed. It was found that as per APTI values Azadirachta sp. came under tolerant range with highest ascorbic acid content whereas Pongamia sp. was under intermediate range with less ascorbic acid content. It was statistically established that ozone has no significant relation with chlorophyll content of Azadirachta sp. which has the highest ascorbic acid content. Whereas ambient ozone concentrations showed significant negative relation with the chlorophyll content of Pongamia sp. p 0.05. Thus it was observed that the plants with high ascorbic acid content are tolerant and have greater ability to remediate pollutants.

Hydrogen sulfide: a new endogenous player in an old mechanism of plant tolerance to high salinity

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Cristiane J. da-Silva

2017-10-01

Full Text Available ABSTRACT High salinity affects plants due to stimulation of osmotic stress. Cell signaling triggered by nitric oxide (NO and hydrogen sulfide (H2S activates a cascade of biochemical events that culminate in plant tolerance to abiotic and biotic stresses. For instance, the NO/H2S-stimulated biochemical events that occur in plants during response to high salinity include the control of reactive oxygen species, activation of antioxidant system, accumulation of osmoprotectants in cytosol, induction of K+ uptake and Na+ cell extrusion or its vacuolar compartmentation among others. This review is a compilation of what we have learned in the last 10 years about NO participation during cell signaling in response to high salinity as well as the role of H2S, a new player in the mechanism of plant tolerance to salt stress. The main sources of NO and H2S in plant cells is also discussed together with the evidence of interplay between both signaling molecules during response to stress.

The sunflower transcription factor HaHB11 confers tolerance to water deficit and salinity to transgenic Arabidopsis and alfalfa plants.

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Cabello, Julieta V; Giacomelli, Jorge I; Gómez, María C; Chan, Raquel L

2017-09-10

Homeodomain-leucine zipper (HD-Zip) transcription factors are unique to the plant kingdom; members of subfamily I are known to be involved in abiotic stress responses. HaHB11 belongs to this subfamily and it was previously shown that it is able to confer improved yield and tolerance to flooding via a quiescent strategy. Here we show that HaHB11 expression is induced by ABA, NaCl and water deficit in sunflower seedlings and leaves. Arabidopsis transgenic plants expressing HaHB11, controlled either by its own promoter or by the constitutive 35S CaMV, presented rolled leaves and longer roots than WT when grown under standard conditions. In addition, these plants showed wider stems and more vascular bundles. To deal with drought, HaHB11 transgenic plants closed their stomata faster and lost less water than controls, triggering an enhanced tolerance to such stress condition and also to salinity stress. Concomitantly, ABA-synthesis and sensing related genes were differentially regulated in HaHB11 transgenic plants. Either under long-term salinity stress or mild drought stress, HaHB11 transgenic plants did not exhibit yield penalties. Moreover, alfalfa transgenic plants were generated which also showed enhanced drought tolerance. Altogether, the results indicated that HaHB11 was able to confer drought and salinity tolerance via a complex mechanism which involves morphological, physiological and molecular changes. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluating relative contribution of osmotolerance and tissue tolerance mechanisms toward salinity stress tolerance in three Brassica species.

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Chakraborty, Koushik; Bose, Jayakumar; Shabala, Lana; Eyles, Alieta; Shabala, Sergey

2016-10-01

Three different species of Brassica, with differential salt sensitivity were used to understand physiological mechanisms of salt tolerance operating in these species and to evaluate the relative contribution of different strategies to cope with salt load. Brassica napus was the most tolerant species in terms of the overall performance, with Brassica juncea and Brassica oleracea being much more sensitive to salt stress with no obvious difference between them. While prominent reduction in net CO2 assimilation was observed in both sensitive species, physiological mechanisms beyond this reduction differed strongly. Brassica juncea plants possessed high osmotolerance and were able to maintain high transpiration rate but showed a significant reduction in leaf chlorophyll content and efficiency of leaf photochemistry. On the contrary, B. oleracea plants possessed the highest (among the three species) tissue tolerance but showed a very significant stomatal limitation of photosynthesis. Electrophysiological experiments revealed that the high tissue tolerance in B. oleracea was related to the ability of leaf mesophyll cells to maintain highly negative membrane potential in the presence of high apoplastic Na(+) . In addition to high osmotolerance, the most tolerant B. napus showed also lesser accumulation of toxic Na(+) and Cl(-) in the leaf, possessed moderate tissue tolerance and had a superior K(+) retention ability. Taken together, the results from this study indicate that the three Brassica species employ very different mechanisms to cope with salinity and, despite its overall sensitivity to salinity, B. oleracea could be recommended as a valuable 'donor' of tissue tolerance genes to confer this trait for marker-assisted breeding programs. © 2016 Scandinavian Plant Physiology Society.

Allocation, stress tolerance and carbon transport in plants: how does phloem physiology affect plant ecology?

Science.gov (United States)

Savage, Jessica A; Clearwater, Michael J; Haines, Dustin F; Klein, Tamir; Mencuccini, Maurizio; Sevanto, Sanna; Turgeon, Robert; Zhang, Cankui

2016-04-01

Despite the crucial role of carbon transport in whole plant physiology and its impact on plant-environment interactions and ecosystem function, relatively little research has tried to examine how phloem physiology impacts plant ecology. In this review, we highlight several areas of active research where inquiry into phloem physiology has increased our understanding of whole plant function and ecological processes. We consider how xylem-phloem interactions impact plant drought tolerance and reproduction, how phloem transport influences carbon allocation in trees and carbon cycling in ecosystems and how phloem function mediates plant relations with insects, pests, microbes and symbiotes. We argue that in spite of challenges that exist in studying phloem physiology, it is critical that we consider the role of this dynamic vascular system when examining the relationship between plants and their biotic and abiotic environment. © 2015 John Wiley & Sons Ltd.

Aluminium resistant, plant growth promoting bacteria induce overexpression of Aluminium stress related genes in Arabidopsis thaliana and increase the ginseng tolerance against Aluminium stress.

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Farh, Mohamed El-Agamy; Kim, Yeon-Ju; Sukweenadhi, Johan; Singh, Priyanka; Yang, Deok-Chun

2017-07-01

Panax ginseng is an important cash crop in the Asian countries due to its pharmaceutical effects, however the plant is exposed to various abiotic stresses, lead to reduction of its quality. One of them is the Aluminum (Al) accumulation. Plant growth promoting bacteria which able to tolerate heavy metals has been considered as a new trend for supporting the growth of many crops in heavy metal occupied areas. In this study, twelve bacteria strains were isolated from rhizosphere of diseased Korean ginseng roots located in Gochang province, Republic of Korea and tested for their ability to grow in Al-embedded broth media. Out of them, four strains (Pseudomonas simiae N3, Pseudomonas fragi N8, Chryseobacterium polytrichastri N10, and Burkholderia ginsengiterrae N11-2) were able to grow. The strains could also show other plant growth promoting activities e.g. auxins and siderophores production and phosphate solubilization. P. simiae N3, C. polytrichastri N10, and B. ginsengiterrae N11-2 strains were able to support the growth of Arabidopsis thaliana stressed by Al while P. fragi N8 could not. Plants inoculated with P. simiae N3, C. polytrichastri N10, and B. ginsengiterrae N11-2 showed higher expression level of Al-stress related genes, AtAIP, AtALS3 and AtALMT1, compared to non-bacterized plants. Expression profiles of the genes reveal the induction of external mechanism of Al resistance by P. simiae N3 and B. ginsengiterrae N11-2 and internal mechanism by C. polytrichastri N10. Korean ginseng seedlings treated with these strains showed higher biomass, particularly the foliar part, higher chlorophyll content than non-bacterized Al-stressed seedlings. According to the present results, these strains can be used in the future for the cultivation of ginseng in Al-persisted locations. Copyright © 2017 Elsevier GmbH. All rights reserved.

Evaluating physiological responses of plants to salinity stress

KAUST Repository

Negrão, Sónia

2016-10-06

Background Because soil salinity is a major abiotic constraint affecting crop yield, much research has been conducted to develop plants with improved salinity tolerance. Salinity stress impacts many aspects of a plant’s physiology, making it difficult to study in toto. Instead, it is more tractable to dissect the plant’s response into traits that are hypothesized to be involved in the overall tolerance of the plant to salinity. Scope and conclusions We discuss how to quantify the impact of salinity on different traits, such as relative growth rate, water relations, transpiration, transpiration use efficiency, ionic relations, photosynthesis, senescence, yield and yield components. We also suggest some guidelines to assist with the selection of appropriate experimental systems, imposition of salinity stress, and obtaining and analysing relevant physiological data using appropriate indices. We illustrate how these indices can be used to identify relationships amongst the proposed traits to identify which traits are the most important contributors to salinity tolerance. Salinity tolerance is complex and involves many genes, but progress has been made in studying the mechanisms underlying a plant’s response to salinity. Nevertheless, several previous studies on salinity tolerance could have benefited from improved experimental design. We hope that this paper will provide pertinent information to researchers on performing proficient assays and interpreting results from salinity tolerance experiments.

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

OpenAIRE

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 pl...

Moving through the stressed genome: Emerging regulatory roles for transposons in plant stress tolerance

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Negi Pooja

2016-10-01

Full Text Available The recognition of a positive correlation between organism genome size with its transposable element (TE content, represents a key discovery of the field of genome biology. Considerable evidence accumulated since then suggests the involvement of TEs in genome structure, evolution and function. The global genome reorganization brought about by transposon activity might play an adaptive/regulatory role in the host response to environmental challenges, reminiscent of McClintock’s original ’Controlling Element’ hypothesis. This regulatory aspect of TEs is also garnering support in light of the recent evidences which project TEs as distributed genomic control modules. According to this view, TEs are capable of actively reprogramming host genes circuits and ultimately fine-tuning the host response to specific environmental stimuli. Moreover, the stress-induced changes in epigenetic status of TE activity may allow TEs to propagate their stress responsive elements to host genes; the resulting genome fluidity can permit phenotypic plasticity and adaptation to stress. Given their predominating presence in the plant genomes, nested organization in the genic regions and potential regulatory role in stress response, TEs hold unexplored potential for crop improvement programs. This review intends to present the current information about the roles played by TEs in plant genome organization, evolution and function, and highlight the regulatory mechanisms in plant stress responses. We will also briefly discuss the connection between TE activity, host epigenetic response and phenotypic plasticity as a critical link for traversing the translational bridge from a purely basic study of TEs, to the applied field of stress adaptation and crop improvement.

Melatonin induction and its role in high light stress tolerance in Arabidopsis thaliana.

Science.gov (United States)

Lee, Hyoung Yool; Back, Kyoungwhan

2018-05-16

In plants, melatonin is a potent bioactive molecule involved in the response against various biotic and abiotic stresses. However, little is known of its defensive role against high light (HL) stress. In this study, we found that melatonin was transiently induced in response to HL stress in Arabidopsis thaliana with a simultaneous increase in the expression of melatonin biosynthetic genes, including serotonin N-acetyltransferase1 (SNAT1). Transient induction of melatonin was also observed in the flu mutant, a singlet oxygen ( 1 O 2 )-producing mutant, upon light exposure, suggestive of melatonin induction by chloroplastidic 1 O 2 against HL stress. An Arabidopsis snat1 mutant was devoid of melatonin induction upon HL stress, resulting in high susceptibility to HL stress. Exogenous melatonin treatment mitigated damage caused by HL stress in the snat1 mutant by reducing O 2 - production and increasing the expression of various ROS-responsive genes. In analogy, an Arabidopsis SNAT1-overexpressing line showed increased tolerance of HL stress concomitant with a reduction in malondialdehyde and ion leakage. A complementation line expressing an Arabidopsis SNAT1 genomic fragment in the snat1 mutant completely restored HL stress susceptibility in the snat1 mutant to levels comparable to that of wild-type Col-0 plants. The results of the analysis of several Arabidopsis genetic lines reveal for the first time at the genetic level that melatonin is involved in conferring HL stress tolerance in plants. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Modulation of Antioxidant Defense System Is Associated with Combined Drought and Heat Stress Tolerance in Citrus

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Sara I. Zandalinas

2017-06-01

Full Text Available Drought and high temperatures are two major abiotic stress factors that often occur simultaneously in nature, affecting negatively crop performance and yield. Moreover, these environmental challenges induce oxidative stress in plants through the production of reactive oxygen species (ROS. Carrizo citrange and Cleopatra mandarin are two citrus genotypes with contrasting ability to cope with the combination of drought and heat stress. In this work, a direct relationship between an increased antioxidant activity and stress tolerance is reported. According to our results, the ability of Carrizo plants to efficiently coordinate superoxide dismutase (SOD, ascorbate peroxidase (APX, catalase (CAT, and glutathione reductase (GR activities involved in ROS detoxification along with the maintenance of a favorable GSH/GSSG ratio could be related to their relative tolerance to this stress combination. On the other hand, the increment of SOD activity and the inefficient GR activation along with the lack of CAT and APX activities in Cleopatra plants in response to the combination of drought and heat stress, could contribute to an increased oxidative stress and the higher sensibility of this citrus genotype to this stress combination.

Evaluating physiological responses of plants to salinity stress

KAUST Repository

Negrã o, Só nia; Schmö ckel, S. M.; Tester, Mark A.

2016-01-01

Background Because soil salinity is a major abiotic constraint affecting crop yield, much research has been conducted to develop plants with improved salinity tolerance. Salinity stress impacts many aspects of a plant’s physiology, making

The molecular mechanism of zinc and cadmium stress response in plants

NARCIS (Netherlands)

Lin, Y.F.; Aarts, M.G.M.

2012-01-01

When plants are subjected to high metal exposure, different plant species take different strategies in response to metal-induced stress. Largely, plants can be distinguished in four groups: metal-sensitive species, metal-resistant excluder species, metal-tolerant non-hyperaccumulator species, and

Enhanced salt stress tolerance of rice plants expressing a vacuolar H+-ATPase subunit c1 (SaVHAc1) gene from the halophyte grass Spartina alterniflora Löisel

Science.gov (United States)

The physiological role of a vacuolar ATPase subunit c1 (SaVHAc1) from a halophyte grass Spartina alterniflora was studied through its expression in rice. The SaVHAc1– expressing plants showed enhanced tolerance to salt stress than the wild-type plants, mainly through adjustments in early stage and p...

Over-expression of SlJA2 decreased heat tolerance of transgenic tobacco plants via salicylic acid pathway.

Science.gov (United States)

Liu, Zhong-Ming; Yue, Meng-Meng; Yang, Dong-Yue; Zhu, Shao-Bo; Ma, Na-Na; Meng, Qing-Wei

2017-04-01

Over-expression of SlJA2 decreased the accumulation of SA, which resulted in significant physiological and gene expression changes in transgenic tobacco plants, leading to the decreased heat tolerance of transgenic tobacco. NAC family, the largest transcription factors in plants, responses to different environmental stimuli. Here, we isolated a typical NAC transcription factor (SlJA2) from tomato and got transgenic tobacco with SlJA2 over-expression. Expression of SlJA2 was induced by heat stress (42 °C), chilling stress (4 °C), drought stress, osmotic stress, abscisic acid, and salicylic acid. Over-expression of SlJA2 decreased the accumulation of salicylic acid by regulating expression of salicylic acid degradation gene under heat stress. Compared to WT plants, stomatal apertures and water loss increased in transgenic plants, and the damage of photosynthetic apparatus and chlorophyll breakdown were more serious in transgenic plants under heat stress. Meanwhile, more H 2 O 2 and O 2 ·- were accumulated transgenic plants and proline synthesis was restricted, which resulted in more serious oxidative damage compared to WT. qRT-PCR analysis showed that over-expression of SlJA2 could down-regulate genes involved in reactive oxygen species scavenging, proline biosynthesis, and response to heat stress. All the above results indicated that SlJA2 may be a negative regulator responded to plant's heat tolerance. Thus, this study provides new insight into roles of NAC family member in plant response to abiotic stress.

Humic Acid Confers HIGH-AFFINITY K+ TRANSPORTER 1-Mediated Salinity Stress Tolerance in Arabidopsis.

Science.gov (United States)

Khaleda, Laila; Park, Hee Jin; Yun, Dae-Jin; Jeon, Jong-Rok; Kim, Min Gab; Cha, Joon-Yung; Kim, Woe-Yeon

2017-12-31

Excessive salt disrupts intracellular ion homeostasis and inhibits plant growth, which poses a serious threat to global food security. Plants have adapted various strategies to survive in unfavorable saline soil conditions. Here, we show that humic acid (HA) is a good soil amendment that can be used to help overcome salinity stress because it markedly reduces the adverse effects of salinity on Arabidopsis thaliana seedlings. To identify the molecular mechanisms of HA-induced salt stress tolerance in Arabidopsis, we examined possible roles of a sodium influx transporter HIGH-AFFINITY K+ TRANSPORTER 1 (HKT1). Salt-induced root growth inhibition in HKT1 overexpressor transgenic plants (HKT1-OX) was rescued by application of HA, but not in wild-type and other plants. Moreover, salt-induced degradation of HKT1 protein was blocked by HA treatment. In addition, the application of HA to HKT1-OX seedlings led to increased distribution of Na+ in roots up to the elongation zone and caused the reabsorption of Na+ by xylem and parenchyma cells. Both the influx of the secondary messenger calcium and its cytosolic release appear to function in the destabilization of HKT1 protein under salt stress. Taken together, these results suggest that HA could be applied to the field to enhance plant growth and salt stress tolerance via post-transcriptional control of the HKT1 transporter gene under saline conditions.

Transgeneration memory of stress in plants.

Science.gov (United States)

Molinier, Jean; Ries, Gerhard; Zipfel, Cyril; Hohn, Barbara

2006-08-31

Owing to their sessile nature, plants are constantly exposed to a multitude of environmental stresses to which they react with a battery of responses. The result is plant tolerance to conditions such as excessive or inadequate light, water, salt and temperature, and resistance to pathogens. Not only is plant physiology known to change under abiotic or biotic stress, but changes in the genome have also been identified. However, it was not determined whether plants from successive generations of the original, stressed plants inherited the capacity for genomic change. Here we show that in Arabidopsis thaliana plants treated with short-wavelength radiation (ultraviolet-C) or flagellin (an elicitor of plant defences), somatic homologous recombination of a transgenic reporter is increased in the treated population and these increased levels of homologous recombination persist in the subsequent, untreated generations. The epigenetic trait of enhanced homologous recombination could be transmitted through both the maternal and the paternal crossing partner, and proved to be dominant. The increase of the hyper-recombination state in generations subsequent to the treated generation was independent of the presence of the transgenic allele (the recombination substrate under consideration) in the treated plant. We conclude that environmental factors lead to increased genomic flexibility even in successive, untreated generations, and may increase the potential for adaptation.

Constitutive over-expression of rice chymotrypsin protease inhibitor gene OCPI2 results in enhanced growth, salinity and osmotic stress tolerance of the transgenic Arabidopsis plants.

Science.gov (United States)

Tiwari, Lalit Dev; Mittal, Dheeraj; Chandra Mishra, Ratnesh; Grover, Anil

2015-07-01

Protease inhibitors are involved primarily in defense against pathogens. In recent years, these proteins have also been widely implicated in response of plants to diverse abiotic stresses. Rice chymotrypsin protease inhibitor gene OCPI2 is highly induced under salt and osmotic stresses. The construct containing the complete coding sequence of OCPI2 cloned downstream to CaMV35S promoter was transformed in Arabidopsis and single copy, homozygous transgenic lines were produced. The transgenic plants exhibited significantly enhanced tolerance to NaCl, PEG and mannitol stress as compared to wild type plants. Importantly, the vegetative and reproductive growth of transgenic plants under unstressed, control conditions was also enhanced: transgenic plants were more vigorous than wild type, resulting into higher yield in terms of silique number. The RWC values and membrane stability index of transgenic in comparison to wild type plants was higher. Higher proline content was observed in the AtOCPI2 lines, which was associated with higher transcript expression of pyrroline-5-carboxylate synthase and lowered levels of proline dehydrogenase genes. The chymotrypsin protease activities were lower in the transgenic as against wild type plants, under both unstressed, control as well as stressed conditions. It thus appears that rice chymotrypsin protease inhibitor gene OCPI2 is a useful candidate gene for genetic improvement of plants against salt and osmotic stress. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

The Arabidopsis RNA-Binding Protein AtRGGA Regulates Tolerance to Salt and Drought Stress

KAUST Repository

Ambrosone, Alfredo; Batelli, Giorgia; Nurcato, Roberta; Aurilia, Vincenzo; Punzo, Paola; Bangarusamy, Dhinoth Kumar; Ruberti, Ida; Sassi, Massimiliano; Leone, Antonietta; Costa, Antonello; Grillo, Stefania

2015-01-01

Salt and drought stress severely reduce plant growth and crop productivity worldwide. The identification of genes underlying stress response and tolerance is the subject of intense research in plant biology. Through microarray analyses, we previously identified in potato (Solanum tuberosum) StRGGA, coding for an Arginine Glycine Glycine (RGG) box-containing RNA-binding protein, whose expression was specifically induced in potato cell cultures gradually exposed to osmotic stress. Here, we show that the Arabidopsis (Arabidopsis thaliana) ortholog, AtRGGA, is a functional RNA-binding protein required for a proper response to osmotic stress. AtRGGA gene expression was up-regulated in seedlings after long-term exposure to abscisic acid (ABA) and polyethylene glycol, while treatments with NaCl resulted in AtRGGA down-regulation. AtRGGA promoter analysis showed activity in several tissues, including stomata, the organs controlling transpiration. Fusion of AtRGGA with yellow fluorescent protein indicated that AtRGGA is localized in the cytoplasm and the cytoplasmic perinuclear region. In addition, the rgga knockout mutant was hypersensitive to ABA in root growth and survival tests and to salt stress during germination and at the vegetative stage. AtRGGA-overexpressing plants showed higher tolerance to ABA and salt stress on plates and in soil, accumulating lower levels of proline when exposed to drought stress. Finally, a global analysis of gene expression revealed extensive alterations in the transcriptome under salt stress, including several genes such as ASCORBATE PEROXIDASE2, GLUTATHIONE S-TRANSFERASE TAU9, and several SMALL AUXIN UPREGULATED RNA-like genes showing opposite expression behavior in transgenic and knockout plants. Taken together, our results reveal an important role of AtRGGA in the mechanisms of plant response and adaptation to stress.

The Arabidopsis RNA-Binding Protein AtRGGA Regulates Tolerance to Salt and Drought Stress

KAUST Repository

Ambrosone, Alfredo

2015-03-17

Salt and drought stress severely reduce plant growth and crop productivity worldwide. The identification of genes underlying stress response and tolerance is the subject of intense research in plant biology. Through microarray analyses, we previously identified in potato (Solanum tuberosum) StRGGA, coding for an Arginine Glycine Glycine (RGG) box-containing RNA-binding protein, whose expression was specifically induced in potato cell cultures gradually exposed to osmotic stress. Here, we show that the Arabidopsis (Arabidopsis thaliana) ortholog, AtRGGA, is a functional RNA-binding protein required for a proper response to osmotic stress. AtRGGA gene expression was up-regulated in seedlings after long-term exposure to abscisic acid (ABA) and polyethylene glycol, while treatments with NaCl resulted in AtRGGA down-regulation. AtRGGA promoter analysis showed activity in several tissues, including stomata, the organs controlling transpiration. Fusion of AtRGGA with yellow fluorescent protein indicated that AtRGGA is localized in the cytoplasm and the cytoplasmic perinuclear region. In addition, the rgga knockout mutant was hypersensitive to ABA in root growth and survival tests and to salt stress during germination and at the vegetative stage. AtRGGA-overexpressing plants showed higher tolerance to ABA and salt stress on plates and in soil, accumulating lower levels of proline when exposed to drought stress. Finally, a global analysis of gene expression revealed extensive alterations in the transcriptome under salt stress, including several genes such as ASCORBATE PEROXIDASE2, GLUTATHIONE S-TRANSFERASE TAU9, and several SMALL AUXIN UPREGULATED RNA-like genes showing opposite expression behavior in transgenic and knockout plants. Taken together, our results reveal an important role of AtRGGA in the mechanisms of plant response and adaptation to stress.

Overexpression of monoubiquitin improves photosynthesis in transgenic tobacco plants following high temperature stress.

Science.gov (United States)

Tian, Fengxia; Gong, Jiangfeng; Zhang, Jin; Feng, Yanan; Wang, Guokun; Guo, Qifang; Wang, Wei

2014-09-01

The ubiquitin/26S proteasome system (Ub/26S) is implicated in abiotic stress responses in plants. In this paper, transgenic tobacco plants overexpressing Ta-Ub2 from wheat were used to study the functions of Ub in the improvement of photosynthesis under high temperature (45°C) stress. We observed higher levels of Ub conjugates in transgenic plants under high temperature stress conditions compared to wild type (WT) as a result of the constitutive overexpression of Ta-Ub2, suggesting increased protein degradation by the 26S proteasome system under high temperature stress. Overexpressing Ub increased the photosynthetic rate (Pn) of transgenic tobacco plants, consistent with the improved ATPase activity in the thylakoid membrane and enhanced efficiency of PSII photochemistry. The higher D1 protein levels following high temperature stress in transgenic plants than WT were also observed. These findings imply that Ub may be involved in tolerance of photosynthesis to high temperature stress in plants. Compared with WT, the transgenic plants showed lower protein carbonylation and malondialdehyde (MDA) levels, less reactive oxygen species (ROS) accumulation, but higher antioxidant enzyme activity under high temperature stress. These findings suggest that the improved antioxidant capacity of transgenic plants may be one of the most important mechanisms underlying Ub-regulated high temperature tolerance. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

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

OpenAIRE

Shailendra eRaikwar; Vineet Kumar Shrivastava; Sarvajeet Singh Gill; Renu eTuteja; Narendra eTuteja; Narendra eTuteja

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. DNA hHelicases, the unique molecular motors, are emerged as potentialprospective molecules to engineer stress tolerance in plants and are involved in a variety of DNA nucleic acid metabolismc processes including DNA repair. The DNA repair helicase, OsXPB2 is an evolutionary conserved pr...

Progress and challenges for abiotic stress proteomics of crop plants.

Science.gov (United States)

Barkla, Bronwyn J; Vera-Estrella, Rosario; Pantoja, Omar

2013-06-01

Plants are continually challenged to recognize and respond to adverse changes in their environment to avoid detrimental effects on growth and development. Understanding the mechanisms that crop plants employ to resist and tolerate abiotic stress is of considerable interest for designing agriculture breeding strategies to ensure sustainable productivity. The application of proteomics technologies to advance our knowledge in crop plant abiotic stress tolerance has increased dramatically in the past few years as evidenced by the large amount of publications in this area. This is attributed to advances in various technology platforms associated with MS-based techniques as well as the accessibility of proteomics units to a wider plant research community. This review summarizes the work which has been reported for major crop plants and evaluates the findings in context of the approaches that are widely employed with the aim to encourage broadening the strategies used to increase coverage of the proteome. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metabolic features involved in drought stress tolerance mechanisms in peanut nodules and their contribution to biological nitrogen fixation.

Science.gov (United States)

Furlan, Ana Laura; Bianucci, Eliana; Castro, Stella; Dietz, Karl-Josef

2017-10-01

Legumes belong to the most important crops worldwide. They increase soil fertility due their ability to establish symbiotic associations with soil microorganisms, known as rhizobia, capable of fixing nitrogen from the atmosphere. However, they are frequently exposed to abiotic stress conditions in particular drought. Such adverse conditions impair the biological nitrogen fixation (BNF) and depend largely on the legume. Therefore, two peanut cultivars with contrasting tolerance to drought, namely the more tolerant EC-98 and the sensitive Granoleico, were investigated to elucidate the relative contribution of BNF to the tolerance to drought. The tolerant cultivar EC-98 sustained growth and BNF similar to the control condition despite the reduced water potential and photosynthesis, suggesting the functioning of distinct metabolic pathways that contributed to enhance the tolerance. The biochemical and metabolomics approaches revealed that nodules from the tolerant cultivar accumulated trehalose, proline and gamma-aminobutyric acid (GABA), metabolites with known function in protecting against drought stress. The amide metabolism was severely affected in nodules from the sensitive cultivar Granoleico as revealed by the low content of asparagine and glutamine in the drought stressed plants. The sensitive cultivar upon rehydration was unable to re-establish a metabolism similar to well-watered plants. This was evidenced by the low level of metabolites and, transcripts and specific activities of enzymes from the carbon (sucrose synthase) and nitrogen (glutamine synthetase) metabolism which decreased below the values of control plants. Therefore, the increased content of metabolites with protective functions under drought stress likely is crucial for the full restoration upon rehydration. Smaller changes of drought stress-related metabolites in nodule are another trait that contributes to the effective control of BNF in the tolerant peanut cultivar (EC-98). Copyright © 2017

Cadmium accumulation and tolerance of Macleaya cordata: a newly potential plant for sustainable phytoremediation in Cd-contaminated soil.

Science.gov (United States)

Nie, Jian; Liu, Yunguo; Zeng, Guangming; Zheng, Bohong; Tan, Xiaofei; Liu, Huan; Xie, Jieli; Gan, Chao; Liu, Wei

2016-05-01

Heavy metal pollution is a major concern of the public due to their threats to the safety of food chains. A 60-day pot experiment was conducted using Macleaya cordata as plant material to investigate the phytoremediation potential and anti-oxidative responses of M. cordata under different Cd stress. Significant growth inhibition phenomenon and toxic symptoms were not detected in the experiment. The high biomass of the plant provided high accumulation capacity for Cd with an average dry weight of 3.6 g. The maximum extraction amount of Cd was 393 μg·plant(-1), suggesting that this species had potential for phytoremediation of Cd-contaminated soil. A slight increase of chlorophyll (CHL) content was observed in Cd10 treatment. The plant was confirmed to have relatively high tolerance to the Cd stress on the basis of tolerance indexes (TI), relative water content, and CHLa/CHLb ratio. M. cordata could maintain high level of superoxide dismutase (SOD) activity under Cd stress, indicating strong tolerance capacity for reactive oxygen species (ROS) in plant cells. Catalase (CAT) activity show a certain range of decline in the experiment compare to the control. And peroxidase (POD) activity in leaves changed irregularly when compared to the control. The malondialdehyde (MDA) content increased as Cd concentration elevated compared to the control. In addition, as an inedible crop with relatively high economic value, M. cordata have shown the advantage of high biomass and high tolerance under Cd stress, which can provide a new plant resource for sustainable phytoremediation.

Drought and submergence tolerance in plants

Energy Technology Data Exchange (ETDEWEB)

Du, Hewei; Zhou, Yufan; Oksenberg, Nir; Ronald, Pamela

2017-11-14

The invention provides methods of genetically modified plants to increase tolerance to drought and/or submergence. The invention additionally provides plants having increased drought and/or submergence tolerance engineered using such methods.

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

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Shailendra eRaikwar

2015-12-01

Full Text Available 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. DNA hHelicases, the unique molecular motors, are emerged as potentialprospective molecules to engineer stress tolerance in plants and are involved in a variety of DNA nucleic acid metabolismc processes including DNA repair. The DNA repair helicase, OsXPB2 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 The analysis of promoter sequence from plant genome is important in understanding the gene regulation. Hereconditions. Here, we report the in silico analysis of novel stress inducible promoter of rice Oryza sativa OsXPB2 (OsXPB2. gene is reported. The in vivo validation of functionality/activity of novel stress inducible promoter of rice OsXPB2 gene promoter under abiotic and hormonal stress conditions was performed by Agrobacterium-mediated transient assay in tobacco leaves using OsXPB2::GUS chimeric construct. Our resultsThe 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-transient assays 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

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......-ionic osmolytes as compared to NaCl. Ramazzottius oberhaeuseri furthermore readily regained activity following gradual increases in non-ionic osmolytes and NaCl of up to 2434 ± 28 and 1905 ± 3 mOsm kg−1, respectively, showing that short-term acclimation promoted salt stress tolerance. Our results suggest...... that the limno-terrestrial R. oberhaeuseri enters a state of quiescence in the face of high external osmotic pressure and that it, in this state, is highly tolerant of ionic and osmotic stress....

Linking salinity stress tolerance with tissue-specific Na+ sequestration in wheat roots

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Honghong eWu

2015-02-01

Full Text Available Salinity stress tolerance is a physiologically complex trait that is conferred by the large array of interacting mechanisms. Among these, vacuolar Na+ sequestration has always been considered as one of the key components differentiating between sensitive and tolerant species and genotypes. However, vacuolar Na+ sequestration has been rarely considered in the context of the tissue-specific expression and regulation of appropriate transporters contributing to Na+ removal from the cytosol. In this work, six bread wheat varieties contrasting in their salinity tolerance (three tolerant and three sensitive were used to understand the essentiality of vacuolar Na+ sequestration between functionally different root tissues, and link it with the overall salinity stress tolerance in this species. Roots of 4-d old wheat seedlings were treated with 100 mM NaCl for 3 days, and then Na+ distribution between cytosol and vacuole was quantified by CoroNa Green fluorescent dye imaging. Our major observations were as follows: 1 salinity stress tolerance correlated positively with vacuolar Na+ sequestration ability in the mature root zone but not in the root apex; 2 Contrary to expectations, cytosolic Na+ levels in root meristem were significantly higher in salt tolerant than sensitive group, while vacuolar Na+ levels showed an opposite trend. These results are interpreted as meristem cells playing a role of the salt sensor; 3 No significant difference in the vacuolar Na+ sequestration ability was found between sensitive and tolerant group in either transition or elongation zones; 4 The overall Na+ accumulation was highest in the elongation zone, suggesting its role in osmotic adjustment and turgor maintenance required to drive root expansion growth. Overall, the reported results suggest high tissue-specificity of Na+ uptake, signalling, and sequestration in wheat root. The implications of these findings for plant breeding for salinity stress tolerance are discussed.

Spliceosomal protein U1A is involved in alternative splicing and salt stress tolerance in Arabidopsis thaliana

KAUST Repository

Gu, Jinbao

2017-12-01

Soil salinity is a significant threat to sustainable agricultural production worldwide. Plants must adjust their developmental and physiological processes to cope with salt stress. Although the capacity for adaptation ultimately depends on the genome, the exceptional versatility in gene regulation provided by the spliceosome-mediated alternative splicing (AS) is essential in these adaptive processes. However, the functions of the spliceosome in plant stress responses are poorly understood. Here, we report the in-depth characterization of a U1 spliceosomal protein, AtU1A, in controlling AS of pre-mRNAs under salt stress and salt stress tolerance in Arabidopsis thaliana. The atu1a mutant was hypersensitive to salt stress and accumulated more reactive oxygen species (ROS) than the wild-type under salt stress. RNA-seq analysis revealed that AtU1A regulates AS of many genes, presumably through modulating recognition of 5′ splice sites. We showed that AtU1A is associated with the pre-mRNA of the ROS detoxification-related gene ACO1 and is necessary for the regulation of ACO1 AS. ACO1 is important for salt tolerance because ectopic expression of ACO1 in the atu1a mutant can partially rescue its salt hypersensitive phenotype. Our findings highlight the critical role of AtU1A as a regulator of pre-mRNA processing and salt tolerance in plants.

Overexpression of AtGRDP2, a novel glycine-rich domain protein, accelerates plant growth and improves stress tolerance

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Maria Azucena Ortega-Amaro

2015-01-01

Full Text Available Proteins with glycine-rich signatures have been reported in a wide variety of organisms including plants, mammalians, fungi, and bacteria. Plant glycine-rich protein genes exhibit developmental and tissue-specific expression patterns. Herein, we present the characterization of the AtGRDP2 gene using Arabidopsis null and knockdown mutants and, Arabidopsis and lettuce over-expression lines. AtGRDP2 encodes a short glycine-rich domain protein, containing a DUF1399 domain and a putative RNA recognition motif. AtGRDP2 transcript is mainly expressed in Arabidopsis floral organs, and its deregulation in Arabidopsis Atgrdp2 mutants and 35S::AtGRDP2 over-expression lines produces alterations in development. The 35S::AtGRDP2 over-expression lines grow faster than the WT, while the Atgrdp2 mutants have a delay in growth and development. The over-expression lines accumulate higher levels of indole-3-acetic acid and, have alterations in the expression pattern of ARF6, ARF8 and miR167 regulators of floral development and auxin signaling. Under salt stress conditions, 35S::AtGRDP2 over-expression lines displayed higher tolerance and increased expression of stress marker genes. Likewise, transgenic lettuce plants over-expressing the AtGRDP2 gene manifest increased growth rate and early flowering time. Our data reveal an important role for AtGRDP2 in Arabidopsis development and stress response, and suggest a connection between AtGRDP2 and auxin signaling.

Soybean Salt Tolerance 1 (GmST1) Reduces ROS Production, Enhances ABA Sensitivity, and Abiotic Stress Tolerance in Arabidopsis thaliana.

Science.gov (United States)

Ren, Shuxin; Lyle, Chimera; Jiang, Guo-Liang; Penumala, Abhishek

2016-01-01

Abiotic stresses, including high soil salinity, significantly reduce crop production worldwide. Salt tolerance in plants is a complex trait and is regulated by multiple mechanisms. Understanding the mechanisms and dissecting the components on their regulatory pathways will provide new insights, leading to novel strategies for the improvement of salt tolerance in agricultural and economic crops of importance. Here we report that soybean salt tolerance 1, named GmST1, exhibited strong tolerance to salt stress in the Arabidopsis transgenic lines. The GmST1-overexpressed Arabidopsis also increased sensitivity to ABA and decreased production of reactive oxygen species under salt stress. In addition, GmST1 significantly improved drought tolerance in Arabidopsis transgenic lines. GmST1 belongs to a 3-prime part of Glyma.03g171600 gene in the current version of soybean genome sequence annotation. However, comparative reverse transcription-polymerase chain reaction analysis around Glyma.03g171600 genomic region confirmed that GmST1 might serve as an intact gene in soybean leaf tissues. Unlike Glyma.03g171600 which was not expressed in leaves, GmST1 was strongly induced by salt treatment in the leaf tissues. By promoter analysis, a TATA box was detected to be positioned close to GmST1 start codon and a putative ABRE and a DRE cis-acting elements were identified at about 1 kb upstream of GmST1 gene. The data also indicated that GmST1-transgenic lines survived under drought stress and showed a significantly lower water loss than non-transgenic lines. In summary, our results suggest that overexpression of GmST1 significantly improves Arabidopsis tolerance to both salt and drought stresses and the gene may be a potential candidate for genetic engineering of salt- and drought-tolerant crops.

Soybean salt tolerance 1 (GmST1 reduces ROS production, enhances ABA sensitivity and abiotic stress tolerance in Arabidopsis thaliana

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Shuxin eRen

2016-04-01

Full Text Available Abiotic stresses, including high soil salinity, significantly reduce crop production worldwide. Salt tolerance in plants is a complex trait and is regulated by multiple mechanisms. Understanding the mechanisms and dissecting the components on their regulatory pathways will provide new insights, leading to novel strategies for the improvement of salt tolerance in agricultural and economic crops of importance. Here we report that soybean salt tolerance 1, named GmST1, exhibited strong tolerance to salt stress in the Arabidopsis transgenic lines. The GmST1-overexpressed Arabidopsis also increased sensitivity to ABA and decreased production of reactive oxygen species (ROS under salt stress. In addition, GmST1 significantly improved drought tolerance in Arabidopsis transgenic lines. GmST1 belongs to a 3-prime part of Glyma.03g171600 gene in the current version of soybean genome sequence annotation. However, comparative RT-PCR analysis around Glyma.03g171600 genomic region confirmed that GmST1 might serve as an intact gene in soybean leaf tissues. Unlike Glyma.03g171600 which was not expressed in leaves, GmST1 was strongly induced by salt treatment in the leaf tissues. By promoter analysis, a TATA box was detected to be positioned close to GmST1 start codon and a putative ABRE and a DRE cis-acting elements were identified at about 1kb upstream of GmST1 gene. The data also indicated that GmST1-transgenic lines survived under drought stress and showed a significantly lower water loss than non-transgenic lines. In summary, our results suggest that overexpression of GmST1 significantly improves Arabidopsis tolerance to both salt and drought stresses and the gene may be a potential candidate for genetic engineering of salt- and drought-tolerant crops.

Isolation and characterization of an atypical LEA protein coding cDNA and its promoter from drought-tolerant plant Prosopis juliflora.

Science.gov (United States)

George, Suja; Usha, B; Parida, Ajay

2009-05-01

Plant growth and productivity are adversely affected by various abiotic and biotic stress factors. Despite the wealth of information on abiotic stress and stress tolerance in plants, many aspects still remain unclear. Prosopis juliflora is a hardy plant reported to be tolerant to drought, salinity, extremes of soil pH, and heavy metal stress. In this paper, we report the isolation and characterization of the complementary DNA clone for an atypical late embryogenesis abundant (LEA) protein (Pj LEA3) and its putative promoter sequence from P. juliflora. Unlike typical LEA proteins, rich in glycine, Pj LEA3 has alanine as the most abundant amino acid followed by serine and shows an average negative hydropathy. Pj LEA3 is significantly different from other LEA proteins in the NCBI database and shows high similarity to indole-3 acetic-acid-induced protein ARG2 from Vigna radiata. Northern analysis for Pj LEA3 in P. juliflora leaves under 90 mM H2O2 stress revealed up-regulation of transcript at 24 and 48 h. A 1.5-kb fragment upstream the 5' UTR of this gene (putative promoter) was isolated and analyzed in silico. The possible reasons for changes in gene expression during stress in relation to the host plant's stress tolerance mechanisms are discussed.

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 ...

Role of Ethylene and Its Cross Talk with Other Signaling Molecules in Plant Responses to Heavy Metal Stress1

Science.gov (United States)

Thao, Nguyen Phuong; Khan, M. Iqbal R.; Thu, Nguyen Binh Anh; Hoang, Xuan Lan Thi; Asgher, Mohd; Khan, Nafees A.; Tran, Lam-Son Phan

2015-01-01

Excessive heavy metals (HMs) in agricultural lands cause toxicities to plants, resulting in declines in crop productivity. Recent advances in ethylene biology research have established that ethylene is not only responsible for many important physiological activities in plants but also plays a pivotal role in HM stress tolerance. The manipulation of ethylene in plants to cope with HM stress through various approaches targeting either ethylene biosynthesis or the ethylene signaling pathway has brought promising outcomes. This review covers ethylene production and signal transduction in plant responses to HM stress, cross talk between ethylene and other signaling molecules under adverse HM stress conditions, and approaches to modify ethylene action to improve HM tolerance. From our current understanding about ethylene and its regulatory activities, it is believed that the optimization of endogenous ethylene levels in plants under HM stress would pave the way for developing transgenic crops with improved HM tolerance. PMID:26246451

Native plant growth promoting bacteria Bacillus thuringiensis and mixed or individual mycorrhizal species improved drought tolerance and oxidative metabolism in Lavandula dentata plants.

Science.gov (United States)

Armada, E; Probanza, A; Roldán, A; Azcón, R

2016-03-15

This study evaluates the responses of Lavandula dentata under drought conditions to the inoculation with single autochthonous arbuscular mycorrhizal (AM) fungus (five fungal strains) or with their mixture and the effects of these inocula with a native Bacillus thuringiensis (endophytic bacteria). These microorganisms were drought tolerant and in general, increased plant growth and nutrition. Particularly, the AM fungal mixture and B. thuringiensis maximized plant biomass and compensated drought stress as values of antioxidant activities [superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase APX)] shown. The AMF-bacteria interactions highly reduced the plant oxidative damage of lipids [malondialdehyde (MDA)] and increased the mycorrhizal development (mainly arbuscular formation representative of symbiotic functionality). These microbial interactions explain the highest potential of dually inoculated plants to tolerate drought stress. B. thuringiensis "in vitro" under osmotic stress does not reduce its PGPB (plant growth promoting bacteria) abilities as indole acetic acid (IAA) and ACC deaminase production and phosphate solubilization indicating its capacity to improve plant growth under stress conditions. Each one of the autochthonous fungal strains maintained their particular interaction with B. thuringiensis reflecting the diversity, intrinsic abilities and inherent compatibility of these microorganisms. In general, autochthonous AM fungal species and particularly their mixture with B. thuringiensis demonstrated their potential for protecting plants against drought and helping plants to thrive in semiarid ecosystems. Copyright © 2015 Elsevier GmbH. All rights reserved.

Overexpression of yeast ArDH gene in chloroplasts confers salinity tolerance in plants (abstract)

International Nuclear Information System (INIS)

Khan, M.S.; Kanwal, B.; Khalid, A.M.; Zafar, Y.; Malik, K.A.

2005-01-01

Water stress due to salinity and drought is the main limiting factor for plant growth, productivity and quality. A common response to water deficit is the accumulation of osmoprotectants such as sugars and amino acids. In yeast, arabitol dehydrogenase is found responsible for the production of arabitol from ribulose-5-phosphate. All plants synthesize ribulose-5-phosphate via pentose pathway in chloroplasts.. Therefore, osmotolerance of the plants could be enhanced through metabolic engineering of chloroplasts by introducing ArDH gene into the plastome, which is responsible for the conversion of ribulose-5- phosphate to arabitol. Here we report high-level expression of arabitol dehydrogenase (ArDH) in chloroplasts. Homoplasmic transgenic plants were recovered on spectinomycin-containing regeneration medium. Transformed tobacco plants survived whereas non-transformed were severely stressed or killed when two weeks old seedlings were exposed to NaCl (up to 400 mM), suggesting a role for arabitol in salt tolerance. Seedlings survived up to five weeks on medium containing high salt concentrations (350-400 mM). Nevertheless, seedlings remained green and grew normal on concentrations up to 350 mM NaCl for several weeks. Hypothesis that membranes are protected under stress conditions due to the arabitol accumulation in chloroplasts, seedlings were grown in liquid medium containing polyethylene glycol (PEG, up to 6%). Seedlings were tolerant to 6% PEG, suggesting that ArDH enzyme protects membranes integrity under stress. Therefore, it is concluded that ArDH gene could be expressed in crop plants to withstand abiotic stresses. (author)

Abiotic stress responses in plants: roles of calmodulin-regulated proteins

Science.gov (United States)

Virdi, Amardeep S.; Singh, Supreet; Singh, Prabhjeet

2015-01-01

Intracellular changes in calcium ions (Ca2+) in response to different biotic and abiotic stimuli are detected by various sensor proteins in the plant cell. Calmodulin (CaM) is one of the most extensively studied Ca2+-sensing proteins and has been shown to be involved in transduction of Ca2+ signals. After interacting with Ca2+, CaM undergoes conformational change and influences the activities of a diverse range of CaM-binding proteins. A number of CaM-binding proteins have also been implicated in stress responses in plants, highlighting the central role played by CaM in adaptation to adverse environmental conditions. Stress adaptation in plants is a highly complex and multigenic response. Identification and characterization of CaM-modulated proteins in relation to different abiotic stresses could, therefore, prove to be essential for a deeper understanding of the molecular mechanisms involved in abiotic stress tolerance in plants. Various studies have revealed involvement of CaM in regulation of metal ions uptake, generation of reactive oxygen species and modulation of transcription factors such as CAMTA3, GTL1, and WRKY39. Activities of several kinases and phosphatases have also been shown to be modulated by CaM, thus providing further versatility to stress-associated signal transduction pathways. The results obtained from contemporary studies are consistent with the proposed role of CaM as an integrator of different stress signaling pathways, which allows plants to maintain homeostasis between different cellular processes. In this review, we have attempted to present the current state of understanding of the role of CaM in modulating different stress-regulated proteins and its implications in augmenting abiotic stress tolerance in plants. PMID:26528296

Native-Invasive Plants vs. Halophytes in Mediterranean Salt Marshes: Stress Tolerance Mechanisms in Two Related Species.

Science.gov (United States)

Al Hassan, Mohamad; Chaura, Juliana; López-Gresa, María P; Borsai, Orsolya; Daniso, Enrico; Donat-Torres, María P; Mayoral, Olga; Vicente, Oscar; Boscaiu, Monica

2016-01-01

Dittrichia viscosa is a Mediterranean ruderal species that over the last decades has expanded into new habitats, including coastal salt marshes, ecosystems that are per se fragile and threatened by human activities. To assess the potential risk that this native-invasive species represents for the genuine salt marsh vegetation, we compared its distribution with that of Inula crithmoides, a taxonomically related halophyte, in three salt marshes located in "La Albufera" Natural Park, near the city of Valencia (East Spain). The presence of D. viscosa was restricted to areas of low and moderate salinity, while I. crithmoides was also present in the most saline zones of the salt marshes. Analyses of the responses of the two species to salt and water stress treatments in controlled experiments revealed that both activate the same physiological stress tolerance mechanisms, based essentially on the transport of toxic ions to the leaves-where they are presumably compartmentalized in vacuoles-and the accumulation of specific osmolytes for osmotic adjustment. The two species differ in the efficiency of those mechanisms: salt-induced increases in Na(+) and Cl(-) contents were higher in I. crithmoides than in D. viscosa, and the osmolytes (especially glycine betaine, but also arabinose, fructose and glucose) accumulated at higher levels in the former species. This explains the (slightly) higher stress tolerance of I. crithmoides, as compared to D. viscosa, established from growth inhibition measurements and their distribution in nature. The possible activation of K(+) transport to the leaves under high salinity conditions may also contribute to salt tolerance in I. crithmoides. Oxidative stress level-estimated from malondialdehyde accumulation-was higher in the less tolerant D. viscosa, which consequently activated antioxidant responses as a defense mechanism against stress; these responses were weaker or absent in the more tolerant I. crithmoides. Based on these results, we

Native-invasive plants vs. halophytes in Mediterranean salt marshes: Stress tolerance mechanisms in two related species

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Mohamad eAl Hassan

2016-04-01

Full Text Available Dittrichia viscosa is a Mediterranean ruderal species that over the last decades has expanded into new habitats, including coastal salt marshes, ecosystems that are per se fragile and threatened by human activities. To assess the potential risk that this native-invasive species represents for the genuine salt marsh vegetation, we compared its distribution with that of Inula crithmoides, a taxonomically related halophyte, in three salt marshes located in ‘La Albufera’ Natural Park, near the city of Valencia (East Spain. The presence of D. viscosa was restricted to areas of low and moderate salinity, while I. crithmoides was also present in the most saline zones of the salt marshes. Analyses of the responses of the two species to salt and water stress treatments in controlled experiments revealed that both activate the same physiological stress tolerance mechanisms, based essentially on the transport of toxic ions to the leaves – where they are presumably compartmentalized in vacuoles – and the accumulation of specific osmolytes for osmotic adjustment. The two species differ in the efficiency of those mechanisms: salt-induced increases in Na+ and Cl- contents were higher in I. crithmoides than in D. viscosa, and the osmolytes (especially glycine betaine, but also arabinose, fructose and glucose accumulated at higher levels in the former species. This explains the (slightly higher stress tolerance of I. crithmoides, as compared to D. viscosa, established from growth inhibition measurements and their distribution in nature. The possible activation of K+ transport to the leaves under high salinity conditions may also contribute to salt tolerance in I. crithmoides. Oxidative stress level – estimated from malondialdehyde accumulation – was higher in the less tolerant D. viscosa, which consequently activated antioxidant responses as a defense mechanism against stress; these responses were weaker or absent in the more tolerant I. crithmoides

Ethylene, nitric oxide and haemoglobins in plant tolerance to flooding

DEFF Research Database (Denmark)

Mur, Luis A J; Gupta, Kapuganti J; Chakraborty, U

2015-01-01

-tolerant species Rumex palustris and the model plant Arabidopsis thaliana have been extensively exploited to reveal some key molecular events. Our groups have recently demonstrated that nitric oxide (NO) triggers the biosynthesis of ethylene during stress and that NO plays key roles in PCD and the hyponastic......As much as 12% of the world's soils may suffer excess water so that flooding is a major limiting factor on crop production in many areas. Plants attempt to deal with submergence by forming root aerenchyma to facilitate oxygen diffusion from the shoot to the root, initiating a hyponastic response....... This chapter will detail our understanding of the roles of ethylene, NO and haemoglobin in flooding stress....

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.

A seed preferential heat shock transcription factor from wheat provides abiotic stress tolerance and yield enhancement in transgenic Arabidopsis under heat stress environment.

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Harsh Chauhan

Full Text Available Reduction in crop yield and quality due to various abiotic stresses is a worldwide phenomenon. In the present investigation, a heat shock factor (HSF gene expressing preferentially in developing seed tissues of wheat grown under high temperatures was cloned. This newly identified heat shock factor possesses the characteristic domains of class A type plant HSFs and shows high similarity to rice OsHsfA2d, hence named as TaHsfA2d. The transcription factor activity of TaHsfA2d was confirmed through transactivation assay in yeast. Transgenic Arabidopsis plants overexpressing TaHsfA2d not only possess higher tolerance towards high temperature but also showed considerable tolerance to salinity and drought stresses, they also showed higher yield and biomass accumulation under constant heat stress conditions. Analysis of putative target genes of AtHSFA2 through quantitative RT-PCR showed higher and constitutive expression of several abiotic stress responsive genes in transgenic Arabidopsis plants over-expressing TaHsfA2d. Under stress conditions, TaHsfA2d can also functionally complement the T-DNA insertion mutants of AtHsfA2, although partially. These observations suggest that TaHsfA2d may be useful in molecular breeding of crop plants, especially wheat, to improve yield under abiotic stress conditions.

Overexpression of a Plasma Membrane-Localized SbSRP-Like Protein Enhances Salinity and Osmotic Stress Tolerance in Transgenic Tobacco

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Avinash Mishra

2017-04-01

Full Text Available An obligate halophyte, Salicornia brachiata grows in salt marshes and is considered to be a potential resource of salt- and drought-responsive genes. It is important to develop an understanding of the mechanisms behind enhanced salt tolerance. To increase this understanding, a novel SbSRP gene was cloned, characterized, over-expressed, and functionally validated in the model plant Nicotiana tabacum. The genome of the halophyte S. brachiata contains two homologs of an intronless SbSRP gene of 1,262 bp in length that encodes for a stress-related protein. An in vivo localization study confirmed that SbSRP is localized on the plasma membrane. Transgenic tobacco plants (T1 that constitutively over-express the SbSRP gene showed improved salinity and osmotic stress tolerance. In comparison to Wild Type (WT and Vector Control (VC plants, transgenic lines showed elevated relative water and chlorophyll content, lower malondialdehyde content, lower electrolyte leakage and higher accumulation of proline, free amino acids, sugars, polyphenols, and starch under abiotic stress treatments. Furthermore, a lower build-up of H2O2 content and superoxide-radicals was found in transgenic lines compared to WT and VC plants under stress conditions. Transcript expression of Nt-APX (ascorbate peroxidase, Nt-CAT (catalase, Nt-SOD (superoxide dismutase, Nt-DREB (dehydration responsive element binding factor, and Nt-AP2 (apetala2 genes was higher in transgenic lines under stress compared to WT and VC plants. The results suggested that overexpression of membrane-localized SbSRP mitigates salt and osmotic stress in the transgenic tobacco plant. It was hypothesized that SbSRP can be a transporter protein to transmit the environmental stimuli downward through the plasma membrane. However, a detailed study is required to ascertain its exact role in the abiotic stress tolerance mechanism. Overall, SbSRP is a potential candidate to be used for engineering salt and osmotic

Overexpression of Grain Amaranth (Amaranthus hypochondriacus) AhERF or AhDOF Transcription Factors in Arabidopsis thaliana Increases Water Deficit- and Salt-Stress Tolerance, Respectively, via Contrasting Stress-Amelioration Mechanisms

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Massange-Sánchez, Julio A.; Palmeros-Suárez, Paola A.; Espitia-Rangel, Eduardo; Rodríguez-Arévalo, Isaac; Sánchez-Segura, Lino; Martínez-Gallardo, Norma A.; Alatorre-Cobos, Fulgencio; Tiessen, Axel; Délano-Frier, John P.

2016-01-01

Two grain amaranth transcription factor (TF) genes were overexpressed in Arabidopsis plants. The first, coding for a group VII ethylene response factor TF (i.e., AhERF-VII) conferred tolerance to water-deficit stress (WS) in transgenic Arabidopsis without affecting vegetative or reproductive growth. A significantly lower water-loss rate in detached leaves coupled to a reduced stomatal opening in leaves of plants subjected to WS was associated with this trait. WS tolerance was also associated with an increased antioxidant enzyme activity and the accumulation of putative stress-related secondary metabolites. However, microarray and GO data did not indicate an obvious correlation between WS tolerance, stomatal closure, and abscisic acid (ABA)-related signaling. This scenario suggested that stomatal closure during WS in these plants involved ABA-independent mechanisms, possibly involving reactive oxygen species (ROS). WS tolerance may have also involved other protective processes, such as those employed for methyl glyoxal detoxification. The second, coding for a class A and cluster I DNA binding with one finger TF (i.e., AhDof-AI) provided salt-stress (SS) tolerance with no evident fitness penalties. The lack of an obvious development-related phenotype contrasted with microarray and GO data showing an enrichment of categories and genes related to developmental processes, particularly flowering. SS tolerance also correlated with increased superoxide dismutase activity but not with augmented stomatal closure. Additionally, microarray and GO data indicated that, contrary to AhERF-VII, SS tolerance conferred by AhDof-AI in Arabidopsis involved ABA-dependent and ABA-independent stress amelioration mechanisms. PMID:27749893

Overexpression of Grain Amaranth (Amaranthus hypochondriacus AhERF or AhDOF Transcription Factors in Arabidopsis thaliana Increases Water Deficit- and Salt-Stress Tolerance, Respectively, via Contrasting Stress-Amelioration Mechanisms.

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Julio A Massange-Sánchez

Full Text Available Two grain amaranth transcription factor (TF genes were overexpressed in Arabidopsis plants. The first, coding for a group VII ethylene response factor TF (i.e., AhERF-VII conferred tolerance to water-deficit stress (WS in transgenic Arabidopsis without affecting vegetative or reproductive growth. A significantly lower water-loss rate in detached leaves coupled to a reduced stomatal opening in leaves of plants subjected to WS was associated with this trait. WS tolerance was also associated with an increased antioxidant enzyme activity and the accumulation of putative stress-related secondary metabolites. However, microarray and GO data did not indicate an obvious correlation between WS tolerance, stomatal closure, and abscisic acid (ABA-related signaling. This scenario suggested that stomatal closure during WS in these plants involved ABA-independent mechanisms, possibly involving reactive oxygen species (ROS. WS tolerance may have also involved other protective processes, such as those employed for methyl glyoxal detoxification. The second, coding for a class A and cluster I DNA binding with one finger TF (i.e., AhDof-AI provided salt-stress (SS tolerance with no evident fitness penalties. The lack of an obvious development-related phenotype contrasted with microarray and GO data showing an enrichment of categories and genes related to developmental processes, particularly flowering. SS tolerance also correlated with increased superoxide dismutase activity but not with augmented stomatal closure. Additionally, microarray and GO data indicated that, contrary to AhERF-VII, SS tolerance conferred by AhDof-AI in Arabidopsis involved ABA-dependent and ABA-independent stress amelioration mechanisms.

Enhancing drought tolerance in C(4) crops.

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Lopes, Marta S; Araus, Jose Luis; van Heerden, Philippus D R; Foyer, Christine H

2011-05-01

Adaptation to abiotic stresses is a quantitative trait controlled by many different genes. Enhancing the tolerance of crop plants to abiotic stresses such as drought has therefore proved to be somewhat elusive in terms of plant breeding. While many C(4) species have significant agronomic importance, most of the research effort on improving drought tolerance has focused on maize. Ideally, drought tolerance has to be achieved without penalties in yield potential. Possibilities for success in this regard are highlighted by studies on maize hybrids performed over the last 70 years that have demonstrated that yield potential and enhanced stress tolerance are associated traits. However, while our understanding of the molecular mechanisms that enable plants to tolerate drought has increased considerably in recent years, there have been relatively few applications of DNA marker technologies in practical C(4) breeding programmes for improved stress tolerance. Moreover, until recently, targeted approaches to drought tolerance have concentrated largely on shoot parameters, particularly those associated with photosynthesis and stay green phenotypes, rather than on root traits such as soil moisture capture for transpiration, root architecture, and improvement of effective use of water. These root traits are now increasingly considered as important targets for yield improvement in C(4) plants under drought stress. Similarly, the molecular mechanisms underpinning heterosis have considerable potential for exploitation in enhancing drought stress tolerance. While current evidence points to the crucial importance of root traits in drought tolerance in C(4) plants, shoot traits may also be important in maintaining high yields during drought.

Grafting improves cucumber water stress tolerance in Saudi Arabia

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Abdulaziz R. Al-Harbi

2018-02-01

Full Text Available Water scarcity is a major limiting factor for crop productivity in arid and semi-arid areas. Grafting elite commercial cultivars onto selected vigorous rootstocks is considered as a useful strategy to alleviate the impact of environmental stresses. This study aims to investigate the feasibility of using grafting to improve fruit yield and quality of cucumber under water stress conditions. Alosama F1 cucumber cultivar (Cucumis sativus L. was grafted onto Affyne (Cucumis sativus L. and Shintoza A90 (Cucurbitamaxima × C. moschata rootstocks. Non-grafted plants were used as control. All genotypes were grown under three surface drip irrigation regimes: 50%, 75% and 100% of the crop evapotranspiration (ETc, which represent high-water stress, moderate-water stress and non-water stress conditions, respectively. Yield and fruit quality traits were analyzed and assessed. In comparison to the non-grafted plants, the best grafting treatment under water stress was Alosama F1 grafted onto Shintoza A90 rootstock. It had an overall improved yield and fruit quality under water stress owing to an increase in the total fruit yield by 27%, from 4.815 kg plant−1 in non-grafted treatment to 6.149 kg plant−1 in grafted treatment under moderate -water stress, total soluble solid contents (13%, titratable acidity (39% and vitamin C (33%. The soil water contents were low in soil surface and increase gradually with soil depth, while salt distribution showed an adverse trend. The positive effects of grafting on plant growth, productivity, and water use efficiency support this strategy as an useful tool for improving water stress tolerance in greenhouse grown cucumber in Saudi Arabia.

Plant Tolerance: A Unique Approach to Control Hemipteran Pests.

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Koch, Kyle G; Chapman, Kaitlin; Louis, Joe; Heng-Moss, Tiffany; Sarath, Gautam

2016-01-01

Plant tolerance to insect pests has been indicated to be a unique category of resistance, however, very little information is available on the mechanism of tolerance against insect pests. Tolerance is distinctive in terms of the plant's ability to withstand or recover from herbivore injury through growth and compensatory physiological processes. Because plant tolerance involves plant compensatory characteristics, the plant is able to harbor large numbers of herbivores without interfering with the insect pest's physiology or behavior. Some studies have observed that tolerant plants can compensate photosynthetically by avoiding feedback inhibition and impaired electron flow through photosystem II that occurs as a result of insect feeding. Similarly, the up-regulation of peroxidases and other oxidative enzymes during insect feeding, in conjunction with elevated levels of phytohormones can play an important role in providing plant tolerance to insect pests. Hemipteran insects comprise some of the most economically important plant pests (e.g., aphids, whiteflies), due to their ability to achieve high population growth and their potential to transmit plant viruses. In this review, results from studies on plant tolerance to hemipterans are summarized, and potential models to understand tolerance are presented.

Increased fitness of rice plants to abiotic stress via habitat adapted symbiosis: a strategy for mitigating impacts of climate change.

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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.

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.

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.

Selenium (Se) improves drought tolerance in crop plants--a myth or fact?

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Ahmad, Rashid; Waraich, Ejaz Ahmad; Nawaz, Fahim; Ashraf, Muhammad Y; Khalid, Muhammad

2016-01-30

Climate change has emerged as one of the most complex challenges of the 21st century and has become an area of interest in the past few decades. Many countries of the world have become extremely vulnerable to the impacts of climate change. The scarcity of water is a serious concern for food security of these countries and climate change has aggravated the risks of extreme events like drought. Oxidative stress, caused by a variety of active oxygen species formed under drought stress, damages many cellular constituents, such as carbohydrates, lipids, nucleic acids and proteins, which ultimately reduces plant growth, respiration and photosynthesis. Se has become an element of interest to many biologists owing to its physiological and toxicological importance. It plays a beneficial role in plants by enhancing growth, reducing damage caused by oxidative stress, enhancing chlorophyll content under light stress, stimulating senesce to produce antioxidants and improving plant tolerance to drought stress by regulating water status. Researchers have adopted different strategies to evaluate the role of selenium in plants under drought stress. Some of the relevant work available regarding the role of Se in alleviating adverse effect of drought stress is discussed in this paper. © 2015 Society of Chemical Industry.

Molecular breeding for drought tolerance in plants: wheat perspective

International Nuclear Information System (INIS)

Hussain, S.S.; Rivandi, A.; Rivandi, A.

2007-01-01

Wheat (Triticum aestivum L.em Thell.) is the first important and strategic cereal crop for the majority of world,s populations. It is the most important staple food of about two billion people (36% of the world population). Due to industrialization, erosion, urbanization, compaction, and the increase in acidity as a result of fertilization, there is a decrease in the available space for agriculture. Environmental conditions such as increased salinity, drought, and freezing cause adverse effects on the growth and productivity of cereal crops such as wheat (Triticum aestivum L.). Though grown under a wide range of climates and soils, wheat is best adapted to temperate regions. Whether the cropping occurs in the temperate areas or the tropics, both types of environments are affected by global warming and the destabilizing effects that it causes, none more serious than the attendant increased variability in rainfall and temperature. Due to the limited insight into the physiological basis of drought tolerance in wheat, a better understanding of some of the mechanisms that enable the plants to adapt to stress and maintain growth during stress periods would help in breeding for drought tolerance. On the other hand, understanding the genetic and genome organization using molecular markers is of great value for plant breeding purposes. (author)

Co-overexpressing a Plasma Membrane and a Vacuolar Membrane Sodium/Proton Antiporter Significantly Improves Salt Tolerance in Transgenic Arabidopsis Plants

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Pehlivan, Necla; Sun, Li; Jarrett, Philip; Yang, Xiaojie; Mishra, Neelam; Chen, Lin; Kadioglu, Asim; Shen, Guoxin; Zhang, Hong

2016-01-01

The Arabidopsis gene AtNHX1 encodes a vacuolar membrane-bound sodium/proton (Na+/H+) antiporter that transports Na+ into the vacuole and exports H+ into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane-bound Na+/H+ antiporter that exports Na+ to the extracellular space and imports H+ into the plant cell. Plants rely on these enzymes either to keep Na+ out of the cell or to sequester Na+ into vacuoles to avoid the toxic level of Na+ in the cytoplasm. Overexpression of AtNHX1 or SOS1 could improve salt tolerance in transgenic plants, but the improved salt tolerance is limited. NaCl at concentration >200 mM would kill AtNHX1-overexpressing or SOS1-overexpressing plants. Here it is shown that co-overexpressing AtNHX1 and SOS1 could further improve salt tolerance in transgenic Arabidopsis plants, making transgenic Arabidopsis able to tolerate up to 250 mM NaCl treatment. Furthermore, co-overexpression of AtNHX1 and SOS1 could significantly reduce yield loss caused by the combined stresses of heat and salt, confirming the hypothesis that stacked overexpression of two genes could substantially improve tolerance against multiple stresses. This research serves as a proof of concept for improving salt tolerance in other plants including crops. PMID:26985021

Induction of drought tolerance in cucumber plants by a consortium of three plant growth-promoting rhizobacterium strains.

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Chun-Juan Wang

Full Text Available Our previous work showed that a consortium of three plant growth-promoting rhizobacterium (PGPR strains (Bacillus cereus AR156, Bacillus subtilis SM21, and Serratia sp. XY21, termed as BBS for short, was a promising biocontrol agent. The present study investigated its effect on drought tolerance in cucumber plants. After withholding watering for 13 days, BBS-treated cucumber plants had much darker green leaves and substantially lighter wilt symptoms than control plants. Compared to the control, the BBS treatment decreased the leaf monodehydroascorbate (MDA content and relative electrical conductivity by 40% and 15%, respectively; increased the leaf proline content and the root recovery intension by 3.45-fold and 50%, respectively; and also maintained the leaf chlorophyll content in cucumber plants under drought stress. Besides, in relation to the control, the BBS treatment significantly enhanced the superoxide dismutase (SOD activity and mitigated the drought-triggered down-regulation of the expression of the genes cAPX, rbcL, and rbcS encoding cytosolic ascorbate peroxidase, and ribulose-1,5-bisphosphate carboxy/oxygenase (Rubisco large and small subunits, respectively, in cucumber leaves. However, 1-aminocyclopropane-1-carboxylate (ACC deaminase activity was undetected in none of the culture solutions of three BBS constituent strains. These results indicated that BBS conferred induced systemic tolerance to drought stress in cucumber plants, by protecting plant cells, maintaining photosynthetic efficiency and root vigor and increasing some of antioxidase activities, without involving the action of ACC deaminase to lower plant ethylene levels.

Comparison between the polypeptide profile of halophilic bacteria and salt tolerant plants.

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Muñoz, G; González, C; Flores, P; Prado, B; Campos, V

1997-12-01

Changes in the polypeptide profile induced by salt stress in halotolerant and halophilic bacteria, isolated from the Atacama desert (northern Chile), were compared with those in the cotyledons of Prosopis chilensis (Leguminoseae) seedlings, a salt tolerant plant. SDS-PAGE analyses show the presence of four predominant polypeptides, with molecular weights around 78, 70, 60 and 44 kDa respectively, both in bacteria and in cotyledons from P. chilensis seedlings raised under salt stress conditions. Moreover, the 60 and 44 kDa polypeptides seem to be salt responsive, since their concentration increases with increasing NaCl in the growth medium. Our results suggest a common mechanism for salt tolerance in prokaryotes and in eukaryotes.

A Medicago truncatula EF-hand family gene, MtCaMP1, is involved in drought and salt stress tolerance.

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Tian-Zuo Wang

Full Text Available BACKGROUND: Calcium-binding proteins that contain EF-hand motifs have been reported to play important roles in transduction of signals associated with biotic and abiotic stresses. To functionally characterize genes of EF-hand family in response to abiotic stress, an MtCaMP1 gene belonging to EF-hand family from legume model plant Medicago truncatula was isolated and its function in response to drought and salt stress was investigated by expressing MtCaMP1 in Arabidopsis. METHODOLOGY/PRINCIPAL FINDINGS: Transgenic Arabidopsis seedlings expressing MtCaMP1 exhibited higher survival rate than wild-type seedlings under drought and salt stress, suggesting that expression of MtCaMP1 confers tolerance of Arabidopsis to drought and salt stress. The transgenic plants accumulated greater amounts of Pro due to up-regulation of P5CS1 and down-regulation of ProDH than wild-type plants under drought stress. There was a less accumulation of Na(+ in the transgenic plants than in WT plants due to reduced up-regulation of AtHKT1 and enhanced regulation of AtNHX1 in the transgenic plants compared to WT plants under salt stress. There was a reduced accumulation of H2O2 and malondialdehyde in the transgenic plants than in WT plants under both drought and salt stress. CONCLUSIONS/SIGNIFICANCE: The expression of MtCaMP1 in Arabidopsis enhanced tolerance of the transgenic plants to drought and salt stress by effective osmo-regulation due to greater accumulation of Pro and by minimizing toxic Na(+ accumulation, respectively. The enhanced accumulation of Pro and reduced accumulation of Na(+ under drought and salt stress would protect plants from water default and Na(+ toxicity, and alleviate the associated oxidative stress. These findings demonstrate that MtCaMP1 encodes a stress-responsive EF-hand protein that plays a regulatory role in response of plants to drought and salt stress.

Insertion of a specific fungal 3'-phosphoadenosine-5'-phosphatase motif into a plant homologue improves halotolerance and drought tolerance of plants.

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Gašparič, Meti Buh; Lenassi, Metka; Gostinčar, Cene; Rotter, Ana; Plemenitaš, Ana; Gunde-Cimerman, Nina; Gruden, Kristina; Zel, Jana

2013-01-01

Soil salinity and drought are among the most serious agricultural and environmental problems of today. Therefore, investigations of plant resistance to abiotic stress have received a lot of attention in recent years. In this study, we identified the complete coding sequence of a 3'-phosphoadenosine-5'-phosphatase protein, ApHal2, from the halotolerant yeast Aureobasidium pullulans. Expression of the ApHAL2 gene in a Saccharomyces cerevisiae hal2 mutant complemented the mutant auxotrophy for methionine, and rescued the growth of the hal2 mutant in media with high NaCl concentrations. A 21-amino-acids-long region of the ApHal2 enzyme was inserted into the Arabidopsis thaliana homologue of Hal2, the SAL1 phosphatase. The inserted sequence included the META motif, which has previously been implicated in increased sodium tolerance of the Hal2 homologue from a related fungal species. Transgenic Arabidopsis plants overexpressing this modified SAL1 (mSAL1) showed improved halotolerance and drought tolerance. In a medium with an elevated salt concentration, mSAL1-expressing plants were twice as likely to have roots in a higher length category in comparison with the wild-type Arabidopsis and with plants overexpressing the native SAL1, and had 5% to 10% larger leaf surface area under moderate and severe salt stress, respectively. Similarly, after moderate drought exposure, the mSAL1-expressing plants showed 14% increased dry weight after revitalisation, with no increase in dry weight of the wild-type plants. With severe drought, plants overexpressing native SAL1 had the worst rehydration success, consistent with the recently proposed role of SAL1 in severe drought. This was not observed for plants expressing mSAL1. Therefore, the presence of this fungal META motif sequence is beneficial under conditions of increased salinity and moderate drought, and shows no drawbacks for plant survival under severe drought. This demonstrates that adaptations of extremotolerant fungi should

Nitrogen nutrition and drought hardening exert opposite effects on the stress tolerance of Pinus pinea L. seedlings.

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Villar-Salvador, Pedro; Peñuelas, Juan L; Jacobs, Douglass F

2013-02-01

Functional attributes determine the survival and growth of planted seedlings in reforestation projects. Nitrogen (N) and water are important resources in the cultivation of forest species, which have a strong effect on plant functional traits. We analyzed the influence of N nutrition on drought acclimation of Pinus pinea L. seedlings. Specifically, we addressed if high N fertilization reduces drought and frost tolerance of seedlings and whether drought hardening reverses the effect of high N fertilization on stress tolerance. Seedlings were grown under two N fertilization regimes (6 and 100 mg N per plant) and subjected to three drought-hardening levels (well-watered, moderate and strong hardening). Water relations, gas exchange, frost damage, N concentration and growth at the end of the drought-hardening period, and survival and growth of seedlings under controlled xeric and mesic outplanting conditions were measured. Relative to low-N plants, high-N plants were larger, had higher stomatal conductance (27%), residual transpiration (11%) and new root growth capacity and closed stomata at higher water potential. However, high N fertilization also increased frost damage (24%) and decreased plasmalemma stability to dehydration (9%). Drought hardening reversed to a great extent the reduction in stress tolerance caused by high N fertilization as it decreased frost damage, stomatal conductance and residual transpiration by 21, 31 and 24%, respectively, and increased plasmalemma stability to dehydration (8%). Drought hardening increased tissue non-structural carbohydrates and N concentration, especially in high-fertilized plants. Frost damage was positively related to the stability of plasmalemma to dehydration (r = 0.92) and both traits were negatively related to the concentration of reducing soluble sugars. No differences existed between moderate and strong drought-hardening treatments. Neither N nutrition nor drought hardening had any clear effect on seedling

A role for SR proteins in plant stress responses.

Science.gov (United States)

Duque, Paula

2011-01-01

Members of the SR (serine/arginine-rich) protein gene family are key players in the regulation of alternative splicing, an important means of generating proteome diversity and regulating gene expression. In plants, marked changes in alternative splicing are induced by a wide variety of abiotic stresses, suggesting a role for this highly versatile gene regulation mechanism in the response to environmental cues. In support of this notion, the expression of plant SR proteins is stress-regulated at multiple levels, with environmental signals controlling their own alternative splicing patterns, phosphorylation status and subcellular distribution. Most importantly, functional links between these RNA-binding proteins and plant stress tolerance are beginning to emerge, including a role in the regulation of abscisic acid (ABA) signaling. Future identification of the physiological mRNA targets of plant SR proteins holds much promise for the elucidation of the molecular mechanisms underlying their role in the response to abiotic stress.

Photooxidative stress in plants

International Nuclear Information System (INIS)

Foyer, C.H.; Lelandais, M.; Kunert, K.J.

1994-01-01

for scavenging by the antioxidative defense systems. The advent of plant transformation, however, may have placed within our grasp the possibility of engineering greater stress tolerance in plants by enhancement of the antioxidative defence system

Co-overexpressing a Plasma Membrane and a Vacuolar Membrane Sodium/Proton Antiporter Significantly Improves Salt Tolerance in Transgenic Arabidopsis Plants.

Science.gov (United States)

Pehlivan, Necla; Sun, Li; Jarrett, Philip; Yang, Xiaojie; Mishra, Neelam; Chen, Lin; Kadioglu, Asim; Shen, Guoxin; Zhang, Hong

2016-05-01

The Arabidopsis gene AtNHX1 encodes a vacuolar membrane-bound sodium/proton (Na(+)/H(+)) antiporter that transports Na(+) into the vacuole and exports H(+) into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane-bound Na(+)/H(+) antiporter that exports Na(+) to the extracellular space and imports H(+) into the plant cell. Plants rely on these enzymes either to keep Na(+) out of the cell or to sequester Na(+) into vacuoles to avoid the toxic level of Na(+) in the cytoplasm. Overexpression of AtNHX1 or SOS1 could improve salt tolerance in transgenic plants, but the improved salt tolerance is limited. NaCl at concentration >200 mM would kill AtNHX1-overexpressing or SOS1-overexpressing plants. Here it is shown that co-overexpressing AtNHX1 and SOS1 could further improve salt tolerance in transgenic Arabidopsis plants, making transgenic Arabidopsis able to tolerate up to 250 mM NaCl treatment. Furthermore, co-overexpression of AtNHX1 and SOS1 could significantly reduce yield loss caused by the combined stresses of heat and salt, confirming the hypothesis that stacked overexpression of two genes could substantially improve tolerance against multiple stresses. This research serves as a proof of concept for improving salt tolerance in other plants including crops. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

Compatible bacterial mixture, tolerant to desiccation, improves maize plant growth.

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Molina-Romero, Dalia; Baez, Antonino; Quintero-Hernández, Verónica; Castañeda-Lucio, Miguel; Fuentes-Ramírez, Luis Ernesto; Bustillos-Cristales, María Del Rocío; Rodríguez-Andrade, Osvaldo; Morales-García, Yolanda Elizabeth; Munive, Antonio; Muñoz-Rojas, Jesús

2017-01-01

Plant growth-promoting rhizobacteria (PGPR) increase plant growth and crop productivity. The inoculation of plants with a bacterial mixture (consortium) apparently provides greater benefits to plant growth than inoculation with a single bacterial strain. In the present work, a bacterial consortium was formulated containing four compatible and desiccation-tolerant strains with potential as PGPR. The formulation had one moderately (Pseudomonas putida KT2440) and three highly desiccation-tolerant (Sphingomonas sp. OF178, Azospirillum brasilense Sp7 and Acinetobacter sp. EMM02) strains. The four bacterial strains were able to adhere to seeds and colonize the rhizosphere of plants when applied in both mono-inoculation and multi-inoculation treatments, showing that they can also coexist without antagonistic effects in association with plants. The effects of the bacterial consortium on the growth of blue maize were evaluated. Seeds inoculated with either individual bacterial strains or the bacterial consortium were subjected to two experimental conditions before sowing: normal hydration or desiccation. In general, inoculation with the bacterial consortium increased the shoot and root dry weight, plant height and plant diameter compared to the non-inoculated control or mono-inoculation treatments. The bacterial consortium formulated in this work had greater benefits for blue maize plants even when the inoculated seeds underwent desiccation stress before germination, making this formulation attractive for future field applications.

Compatible bacterial mixture, tolerant to desiccation, improves maize plant growth.

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Dalia Molina-Romero

Full Text Available Plant growth-promoting rhizobacteria (PGPR increase plant growth and crop productivity. The inoculation of plants with a bacterial mixture (consortium apparently provides greater benefits to plant growth than inoculation with a single bacterial strain. In the present work, a bacterial consortium was formulated containing four compatible and desiccation-tolerant strains with potential as PGPR. The formulation had one moderately (Pseudomonas putida KT2440 and three highly desiccation-tolerant (Sphingomonas sp. OF178, Azospirillum brasilense Sp7 and Acinetobacter sp. EMM02 strains. The four bacterial strains were able to adhere to seeds and colonize the rhizosphere of plants when applied in both mono-inoculation and multi-inoculation treatments, showing that they can also coexist without antagonistic effects in association with plants. The effects of the bacterial consortium on the growth of blue maize were evaluated. Seeds inoculated with either individual bacterial strains or the bacterial consortium were subjected to two experimental conditions before sowing: normal hydration or desiccation. In general, inoculation with the bacterial consortium increased the shoot and root dry weight, plant height and plant diameter compared to the non-inoculated control or mono-inoculation treatments. The bacterial consortium formulated in this work had greater benefits for blue maize plants even when the inoculated seeds underwent desiccation stress before germination, making this formulation attractive for future field applications.

Molecular and Functional Characterization of a Wheat B2 Protein Imparting Adverse Temperature Tolerance and Influencing Plant Growth

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akanksha esingh

2016-05-01

Full Text Available Genomic attempts were undertaken to elucidate the plant developmental responses to heat stress, and to characterize the roles of B2 protein in mediating those responses. A wheat EST for B2 protein was identified which was cloned and characterized to assess its functional relevance causing plant growth and development during stress adaptation. Here, we show that wheat B2 protein is highly expressed in root and shoot tissues as well as in developing seed tissues under high temperature stress conditions. Morphological studies of transgenic Arabidopsis overexpressing gene encoding wheat B2 protein and Δb2 mutant plants were studied at major developmental stages. The stunted growth phenotype of mutant plants, together with hypocotyl and root elongation analysis of transgenic plants showed that B2 protein exhibits a crucial role in plant growth and development. Additional physiological analyses highlights the role of B2 protein in increased tolerance to heat and cold stresses by maintaining high chlorophyll content, strong activity of photosystem II and less membrane damage of overexpression transgenics as compared with the wild-type. Furthermore, the constitutive overexpression of TaB2 in Arabidopsis resulted in ABA hypersensitivity. Taken together, these studies suggest a novel perspectives of B2 protein in plant development and in mediating the thermal stress tolerance.

Determination of moisture deficit and heat stress tolerance in corn using physiological measurements and a low-cost microcontroller-based monitoring system

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In the southern United States, corn production encounters moisture deficit coupled with high temperature stress, particularly during the reproductive stage of the plant. In evaluating plants for environmental stress tolerance, it is important to monitor changes in their physical environment under na...

Insights on the Impact of Arbuscular Mycorrhizal Symbiosis on Tomato Tolerance to Water Stress.

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Chitarra, Walter; Pagliarani, Chiara; Maserti, Biancaelena; Lumini, Erica; Siciliano, Ilenia; Cascone, Pasquale; Schubert, Andrea; Gambino, Giorgio; Balestrini, Raffaella; Guerrieri, Emilio

2016-06-01

Arbuscular mycorrhizal (AM) fungi, which form symbioses with the roots of the most important crop species, are usually considered biofertilizers, whose exploitation could represent a promising avenue for the development in the future of a more sustainable next-generation agriculture. The best understood function in symbiosis is an improvement in plant mineral nutrient acquisition, as exchange for carbon compounds derived from the photosynthetic process: this can enhance host growth and tolerance to environmental stresses, such as water stress (WS). However, physiological and molecular mechanisms occurring in arbuscular mycorrhiza-colonized plants and directly involved in the mitigation of WS effects need to be further investigated. The main goal of this work is to verify the potential impact of AM symbiosis on the plant response to WS To this aim, the effect of two AM fungi (Funneliformis mosseae and Rhizophagus intraradices) on tomato (Solanum lycopersicum) under the WS condition was studied. A combined approach, involving ecophysiological, morphometric, biochemical, and molecular analyses, has been used to highlight the mechanisms involved in plant response to WS during AM symbiosis. Gene expression analyses focused on a set of target genes putatively involved in the plant response to drought, and in parallel, we considered the expression changes induced by the imposed stress on a group of fungal genes playing a key role in the water-transport process. Taken together, the results show that AM symbiosis positively affects the tolerance to WS in tomato, with a different plant response depending on the AM fungi species involved. © 2016 American Society of Plant Biologists. All Rights Reserved.

Potential application of metabolic engineering to tune the production of compatible solutes for enhancing tolerance of crop plants to salinity/drought (abstract)

International Nuclear Information System (INIS)

Sharmila, P.; Saradhi, P.P.

2005-01-01

Essential need to develop genotypes of crop plants that can substantially withstand salinity and drought with little yield losses is being increasingly felt, as the cultivable agricultural lands is increasingly being exposed to these stresses. In-spite of gains in productivity, conventional plant breeding methods have their limitations either due to limited gene pool or due to species barrier for gene transfer. Modern molecular tools have paved ways for identification of genes imparting abiotic stress tolerance in unrelated species/organisms and to transfer the selected genes into desirable crop plant species by conquering the incompatibility barriers. In fact, now genetic engineering has been widely realized to be in important tool for developing abiotic stress tolerant crop plants. Abiotic stress tolerance is a complex phenomenon involving simultaneous expression of a number of genes coupled with an interaction of varying weather variables and crop phonology. However, in order to tackle the issue, successful attempts have been made in identifying genes enhancing abiotic stress tolerance. The genes for biosynthesis of various compatible solutes (viz., mtlD for mannitol: P5CS or P5CSF129A for proline; coda/cox or belA/beIB for glycinebetaine' lpsl for trehalose; PINOI for inositol) have been demonstrated to enhance abiotic stress tolerance of plants. We have isolated the codA gene (Accession number AY589052) for choline oxidase from an Indian strain of Arthrobacter sp. from IMTECH (Chandigarh) and the mtlD genes from local strains of E. coli (accession number A Y523630) and halobacterium sp. (Accession number A Y52363 1). We have enhanced the tolerance of Brassica juncea to salt, drought and low temperature stresses by introducing the codA gene from Arthrobacter globiformis using Agrobacterium tumefaciens mediated transformation. Presenting our research team is busy developing genotypes of chickpea black gram, peanut and sorghum besides mustard with enhanced

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

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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

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

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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.

Drought-tolerance of wheat improved by rhizosphere bacteria from harsh environments: enhanced biomass production and reduced emissions of stress volatiles.

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Salme Timmusk

Full Text Available Water is the key resource limiting world agricultural production. Although an impressive number of research reports have been published on plant drought tolerance enhancement via genetic modifications during the last few years, progress has been slower than expected. We suggest a feasible alternative strategy by application of rhizospheric bacteria coevolved with plant roots in harsh environments over millions of years, and harboring adaptive traits improving plant fitness under biotic and abiotic stresses. We show the effect of bacterial priming on wheat drought stress tolerance enhancement, resulting in up to 78% greater plant biomass and five-fold higher survivorship under severe drought. We monitored emissions of seven stress-related volatiles from bacterially-primed drought-stressed wheat seedlings, and demonstrated that three of these volatiles are likely promising candidates for a rapid non-invasive technique to assess crop drought stress and its mitigation in early phases of stress development. We conclude that gauging stress by elicited volatiles provides an effectual platform for rapid screening of potent bacterial strains and that priming with isolates of rhizospheric bacteria from harsh environments is a promising, novel way to improve plant water use efficiency. These new advancements importantly contribute towards solving food security issues in changing climates.

Reduced Drought Tolerance by CRISPR/Cas9-Mediated SlMAPK3 Mutagenesis in Tomato Plants.

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Wang, Liu; Chen, Lin; Li, Rui; Zhao, Ruirui; Yang, Meijing; Sheng, Jiping; Shen, Lin

2017-10-04

Drought stress is one of the most destructive environmental factors that affect tomato plants adversely. Mitogen-activated protein kinases (MAPKs) are important signaling molecules that respond to drought stress. In this study, SlMAPK3 was induced by drought stress, and the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (CRISPR/Cas9) system was utilized to generate slmapk3 mutants. Two independent T1 transgenic lines and wild-type (WT) tomato plants were used for analysis of drought tolerance. Compared with WT plants, slmapk3 mutants exhibited more severe wilting symptom, higher hydrogen peroxide content, lower antioxidant enzymes activities, and suffered more membrane damage under drought stress. Furthermore, knockout of SlMAPK3 led to up- or down-regulated expressions of drought stress-responsive genes including SlLOX, SlGST, and SlDREB. The results suggest that SlMAPK3 is involved in drought response in tomato plants by protecting cell membranes from oxidative damage and modulating transcription of stress-related genes.

Overexpression of the Wheat Expansin Gene TaEXPA2 Improved Seed Production and Drought Tolerance in Transgenic Tobacco Plants.

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Chen, Yanhui; Han, Yangyang; Zhang, Meng; Zhou, Shan; Kong, Xiangzhu; Wang, Wei

2016-01-01

Expansins are cell wall proteins that are grouped into two main families, α-expansins and β-expansins, and they are implicated in the control of cell extension via the disruption of hydrogen bonds between cellulose and matrix glucans. TaEXPA2 is an α-expansin gene identified in wheat. Based on putative cis-regulatory elements in the TaEXPA2 promoter sequence and the expression pattern induced when polyethylene glycol (PEG) is used to mimic water stress, we hypothesized that TaEXPA2 is involved in plant drought tolerance and plant development. Through transient expression of 35S::TaEXPA2-GFP in onion epidermal cells, TaEXPA2 was localized to the cell wall. Constitutive expression of TaEXPA2 in tobacco improved seed production by increasing capsule number, not seed size, without having any effect on plant growth patterns. The transgenic tobacco exhibited a significantly greater tolerance to water-deficiency stress than did wild-type (WT) plants. We found that under drought stress, the transgenic plants maintained a better water status. The accumulated content of osmotic adjustment substances, such as proline, in TaEXPA2 transgenic plants was greater than that in WT plants. Transgenic plants also displayed greater antioxidative competence as indicated by their lower malondialdehyde (MDA) content, relative electrical conductivity, and reactive oxygen species (ROS) accumulation than did WT plants. This result suggests that the transgenic plants suffer less damage from ROS under drought conditions. The activities of some antioxidant enzymes as well as expression levels of several genes encoding key antioxidant enzymes were higher in the transgenic plants than in the WT plants under drought stress. Collectively, our results suggest that ectopic expression of the wheat expansin gene TaEXPA2 improves seed production and drought tolerance in transgenic tobacco plants.

Expression of Finger Millet EcDehydrin7 in Transgenic Tobacco Confers Tolerance to Drought Stress.

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Singh, Rajiv Kumar; Singh, Vivek Kumar; Raghavendrarao, Sanagala; Phanindra, Mullapudi Lakshmi Venkata; Venkat Raman, K; Solanke, Amolkumar U; Kumar, Polumetla Ananda; Sharma, Tilak Raj

2015-09-01

One of the critical alarming constraints for agriculture is water scarcity. In the current scenario, global warming due to climate change and unpredictable rainfall, drought is going to be a master player and possess a big threat to stagnating gene pool of staple food crops. So it is necessary to understand the mechanisms that enable the plants to cope with drought stress. In this study, effort was made to prospect the role of EcDehydrin7 protein from normalized cDNA library of drought tolerance finger millet in transgenic tobacco. Biochemical and molecular analyses of T0 transgenic plants were done for stress tolerance. Leaf disc assay, seed germination test, dehydration assay, and chlorophyll estimation showed EcDehydrin7 protein directly link to drought tolerance. Northern and qRT PCR analyses shows relatively high expression of EcDehydrin7 protein compare to wild type. T0 transgenic lines EcDehydrin7(11) and EcDehydrin7(15) shows superior expression among all lines under study. In summary, all results suggest that EcDehydrin7 protein has a remarkable role in drought tolerance and may be used for sustainable crop breeding program in other food crops.

Delaying chloroplast turnover increases water-deficit stress tolerance through the enhancement of nitrogen assimilation in rice.

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Sade, Nir; Umnajkitikorn, Kamolchanok; Rubio Wilhelmi, Maria Del Mar; Wright, Matthew; Wang, Songhu; Blumwald, Eduardo

2018-02-12

Abiotic stress-induced senescence in crops is a process particularly affecting the photosynthetic apparatus, decreasing photosynthetic activity and inducing chloroplast degradation. A pathway for stress-induced chloroplast degradation that involves the CHLOROPLAST VESICULATION (CV) gene was characterized in rice (Oryza sativa) plants. OsCV expression was up-regulated with the age of the plants and when plants were exposed to water-deficit conditions. The down-regulation of OsCV expression contributed to the maintenance of the chloroplast integrity under stress. OsCV-silenced plants displayed enhanced source fitness (i.e. carbon and nitrogen assimilation) and photorespiration, leading to water-deficit stress tolerance. Co-immunoprecipitation, intracellular co-localization, and bimolecular fluorescence demonstrated the in vivo interaction between OsCV and chloroplastic glutamine synthetase (OsGS2), affecting source-sink relationships of the plants under stress. Our results would indicate that the OsCV-mediated chloroplast degradation pathway is involved in the regulation of nitrogen assimilation during stress-induced plant senescence. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Catch the Best: Novel Screening Strategy to Select Stress Protecting Agents for Crop Plants

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Christin Zachow

2013-11-01

Full Text Available Climate change increases stress levels for crops and affects the economic and environmental aspects of agricultural management systems. The application of stress tolerance-mediating microorganisms is an auspicious strategy for improving crop protection, and as such, we developed a direct selection strategy to obtain cultivable microorganisms from promising bioresources using the bait plants, maize, oilseed rape, sorghum and sugar beet. Alpine mosses, lichens and primrose were selected as bioresources, as each is adapted to adverse environmental conditions. A 10% crop-specific selection was found for bait plant rhizosphere communities using cultivation-independent fingerprints, and their potential role as stress protecting agents (SPA was evaluated following the cultivation of captured bacteria. In addition to assays identifying phytopathogen antagonism and plant growth promotion capacities, our evaluation included those that test the ability to allocate nutrients. Moreover, we developed new assays to measure tolerance in diverse stress conditions. A score scheme was applied to select SPAs with desired properties, and three Pseudomonas species with pronounced antagonistic activity that showed elevated tolerance to desiccation and an improved seed germination rate were subsequently chosen. Screening for environmentally-conditioned and host-adapted microorganisms provides a novel tool for target-oriented exploitation of microbial bioresources for the management of ecofriendly crops facing biotic and abiotic stresses.

Generation of peanut drought tolerant plants by pingyangmycin-mediated in vitro mutagenesis and hydroxyproline-resistance screening.

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Jiongming Sui

Full Text Available In order to enlarge the potential resources of drought-tolerant peanuts, we conducted in vitro mutagenesis with Pingyangmycin (PYM as the mutagen as well as directed screening on a medium supplemented with Hydroxyproline (HYP. After being extracted from mature seeds (cv. Huayu 20, the embryonic leaflets were cultured on somatic embryogenesis-induction medium with 4 mg/L PYM and the generated embryos were successively transferred to a germination medium with 4 and then 8 mmol/L HYP to screen HYP-tolerant plantlets. After that, these plantlets were grafted and transplanted to the experimental field. In the next generation, all seeds were sown in the field, and phenotype variation and trait segregation can be observed in most of the offspring (M2 generation. The M3 generation individuals were subjected to drought stress at the seedling stages. The activities of SOD and POD were substantially increased in eight offspring of 11 HYP-tolerant, regenerated plants than in their mutagenic parents. To determine the correlation between mutant phenotypes and genomic modification, we carried out a comparison of the DNA polymorphisms between the mutagenic parents and 13 M3 generation individuals from different HYP-tolerant, regenerated plants with SSR primers. Results showed that most mutants and parent plants had signs of polymorphisms. Under drought stress, some M3 generation individuals of 10 original HYP-tolerant, regenerated plants produced more pods than the mutagenic parent; twenty individuals among them produced >60 g pods/plant. M4-generation seeds were tested for quality characteristics by Near Infrared Spectroscopy (NIS and nine individuals with higher protein content (>30% and 21 individuals with higher oil content (>58% were screened. We concluded that the use of PYM-based in vitro mutagenesis in combination with directed screening with HYP is effective for the creation of potential drought-tolerant mutants of peanut.

Ectopic expression of phloem motor protein pea forisome PsSEO-F1 enhances salinity stress tolerance in tobacco.

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Srivastava, Vineet Kumar; Raikwar, Shailendra; Tuteja, Renu; Tuteja, Narendra

2016-05-01

PsSEOF-1 binds to calcium and its expression is upregulated by salinity treatment. PsSEOF - 1 -overexpressing transgenic tobacco showed enhanced salinity stress tolerance by maintaining cellular ion homeostasis and modulating ROS-scavenging pathway. Calcium (Ca(2+)) plays important role in growth, development and stress tolerance in plants. Cellular Ca(2+) homeostasis is achieved by the collective action of channels, pumps, antiporters and by Ca(2+) chelators present in the cell like calcium-binding proteins. Forisomes are ATP-independent mechanically active motor proteins known to function in wound sealing of injured sieve elements of phloem tissue. The Ca(2+)-binding activity of forisome and its role in abiotic stress signaling were largely unknown. Here we report the Ca(2+)-binding activity of pea forisome (PsSEO-F1) and its novel function in promoting salinity tolerance in transgenic tobacco. Native PsSEO-F1 promoter positively responded in salinity stress as confirmed using GUS reporter. Overexpression of PsSEO-F1 tobacco plants confers salinity tolerance by alleviating ionic toxicity and increased ROS scavenging activity which probably results in reduced membrane damage and improved yield under salinity stress. Evaluation of several physiological indices shows an increase in relative water content, electrolyte leakage, proline accumulation and chlorophyll content in transgenic lines as compared with null-segregant control. Expression of several genes involved in cellular homeostasis is perturbed by PsSEO-F1 overexpression. These findings suggest that PsSEO-F1 provides salinity tolerance through cellular Ca(2+) homeostasis which in turn modulates ROS machinery providing indirect link between Ca(2+) and ROS signaling under salinity-induced perturbation. PsSEO-F1 most likely functions in salinity stress tolerance by improving antioxidant machinery and mitigating ion toxicity in transgenic lines. This finding should make an important contribution in our better

International Conference on Biotechnology for Salinity and Drought Tolerance in Plants

International Nuclear Information System (INIS)

Malik, K.A.; Mahmood, K.

2005-01-01

International Conference on Biotechnology for Salinity and Drought Tolerance in Plants was held from 28-29 March, 2005 at Islamabad, Pakistan. Abstracts of this conference have been presented in this proceeding. There were six technical sessions like 1) Stress Physiology/Ion Transport, 2) Stress Sensing and Signaling, 3) Genomis, Metabolomics and Proteomics, 4) Genetic Engineering, 5) Gene Expression, 6) Field Studies and Management. This seminar was quite useful specially drought resistance and salinity in the soil. Researches exchange their views in the seminar. (A.B.)

Over-expression of a NAC 67 transcription factor from finger millet (Eleusine coracana L.) confers tolerance against salinity and drought stress in rice.

Science.gov (United States)

Rahman, Hifzur; Ramanathan, Valarmathi; Nallathambi, Jagedeeshselvam; Duraialagaraja, Sudhakar; Muthurajan, Raveendran

2016-05-11

NAC proteins (NAM (No apical meristem), ATAF (Arabidopsis transcription activation factor) and CUC (cup-shaped cotyledon)) are plant-specific transcription factors reported to be involved in regulating growth, development and stress responses. Salinity responsive transcriptome profiling in a set of contrasting finger millet genotypes through RNA-sequencing resulted in the identification of a NAC homolog (EcNAC 67) exhibiting differential salinity responsive expression pattern. Full length cDNA of EcNAC67 was isolated, characterized and validated for its role in abiotic stress tolerance through agrobacterium mediated genetic transformation in a rice cultivar ASD16. Bioinformatics analysis of putative NAC transcription factor (TF) isolated from a salinity tolerant finger millet showed its genetic relatedness to NAC67 family TFs in related cereals. Putative transgenic lines of rice over-expressing EcNAC67 were generated through Agrobacterium mediated transformation and presence/integration of transgene was confirmed through PCR and southern hybridization analysis. Transgenic rice plants harboring EcNAC67 showed enhanced tolerance against drought and salinity under greenhouse conditions. Transgenic rice plants were found to possess higher root and shoot biomass during stress and showed better revival ability upon relief from salinity stress. Upon drought stress, transgenic lines were found to maintain higher relative water content and lesser reduction in grain yield when compared to non-transgenic ASD16 plants. Drought induced spikelet sterility was found to be much lower in the transgenic lines than the non-transgenic ASD16. Results revealed the significant role of EcNAC67 in modulating responses against dehydration stress in rice. No detectable abnormalities in the phenotypic traits were observed in the transgenic plants under normal growth conditions. Results indicate that EcNAC67 can be used as a novel source for engineering tolerance against drought and salinity

A novel ethylene-responsive factor from Tamarix hispida, ThERF1, is a GCC-box- and DRE-motif binding protein that negatively modulates abiotic stress tolerance in Arabidopsis.

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Wang, Liuqiang; Qin, Liping; Liu, Wenjin; Zhang, Daoyuan; Wang, Yucheng

2014-09-01

Ethylene-responsive factor (ERF) family is one of the largest families of plant-specific transcription factor that can positively or negatively regulate abiotic stress tolerance. However, their functions in regulating abiotic stress tolerance are still not fully understood. In this study, we characterized the functions of an ERF gene from Tamarix hispida, ThERF1, which can negatively regulate abiotic stress tolerance. The expression of ThERF1 was induced by salinity, PEG-simulated drought and abscisic acid (ABA) treatments. ThERF1 can specifically bind to GCC-box and DRE motifs. Overexpression of ThERF1 in transgenic Arabidopsis plants showed inhibited seed germination, and decreased fresh weight gain and root growth compared with wild-type (WT) plants. In addition, the transcript levels of several superoxide dismutase (SOD) and peroxidase (POD) genes in transgenic plants were significantly inhibited compared with in WT plants, resulting in decreased SOD and POD activities in transgenic plants under salt and drought stress conditions. Furthermore, the reactive oxygen species (ROS) levels, malondialdehyde (MDA) contents and cell membrane damage in ThERF1-transformed plants were all highly increased relative to WT plants. Our results suggest that ThERF1 negatively regulates abiotic stress tolerance by strongly inhibiting the expression of SOD and POD genes, leading to decreased ROS-scavenging ability. © 2014 Scandinavian Plant Physiology Society.

Untangling metabolic and spatial interactions of stress tolerance in plants. 2. Accelerated method for measuring and predicting stress tolerance. Can we unravel the mysteries of the interactions between photosynthesis and respiration?

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Biel, Karl Y; Nishio, John N

2010-09-01

A simple method using the O(2) electrode that allows examination of the response of respiration and photosynthesis in leaf slices or algae to anoxia and high light under different temperatures useful for the examination of the interactions among photosynthesis, photorespiration, and respiration is described. The method provides a quantifiable assessment of stress tolerance that also permits us to examine fundamental biochemically and genetically related responses involved in stress tolerance and the cooperation among organelles. Additionally, we demonstrated a role for compounds, such as NO(-)(3) and oxaloacetate, as protective agents against photoinhibition, and we examined the role of dark adaptation in the activation of photosynthesis and NO(-)(3)-dependent O(2) oxygen evolution. A physiological and ecological role of a dark period (night) in stress tolerance is presented. Utilizing the method to follow changes in such metabolic activities as protein synthesis, protein conformation states, enzymes activity, carbon metabolism, and gene expression at different points during the treatments will be educational.

HKT transporters mediate salt stress resistance in plants: from structure and function to the field.

Science.gov (United States)

Hamamoto, Shin; Horie, Tomoaki; Hauser, Felix; Deinlein, Ulrich; Schroeder, Julian I; Uozumi, Nobuyuki

2015-04-01

Plant cells are sensitive to salinity stress and do not require sodium as an essential element for their growth and development. Saline soils reduce crop yields and limit available land. Research shows that HKT transporters provide a potent mechanism for mediating salt tolerance in plants. Knowledge of the molecular ion transport and regulation mechanisms and the control of HKT gene expression are crucial for understanding the mechanisms by which HKT transporters enhance crop performance under salinity stress. This review focuses on HKT transporters in monocot plants and in Arabidopsis as a dicot plant, as a guide to efforts toward improving salt tolerance of plants for increasing the production of crops and bioenergy feedstocks. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of tolerance to soil acidity among crop plants. II. Tolerance to high levels of aluminum and manganese. Comparative plant nutrition

Energy Technology Data Exchange (ETDEWEB)

Tanaka, A; Hayakawa, Y

1975-01-01

Research was conducted by growing various species of plants in solutions containing high concentrations of manganese or aluminum. A comparison was made of the tolerance of these plants to low pH and to the manganese and aluminum. In addition, the element content of the plants was compared. Plants high in calcium were found to have an intermediate tolerance to high concentrations of manganese and aluminum. Gramineae had a high tolerance to these elements and to low pH. They also accumulated high levels of these elements. Legumes had a high tolerance to manganese and aluminum and to low pH. However, they also accumulated high levels of these elements. Legumes had a high tolerance to manganese and aluminum and to low pH. However, they also accumulated high levels of these elements. Cruciferae had a low tolerance to the elements and to low pH. They contained low levels of manganese and aluminum. Chenopodiaceae had a low tolerance to the elements as well as low element contents. However, they were highly tolerant to low pH.

Knock-out of Arabidopsis AtNHX4 gene enhances tolerance to salt stress

International Nuclear Information System (INIS)

Li, Hong-Tao; Liu, Hua; Gao, Xiao-Shu; Zhang, Hongxia

2009-01-01

AtNHX4 belongs to the monovalent cation:proton antiporter-1 (CPA1) family in Arabidopsis. Several members of this family have been shown to be critical for plant responses to abiotic stress, but little is known on the biological functions of AtNHX4. Here, we provide the evidence that AtNHX4 plays important roles in Arabidopsis responses to salt stress. Expression of AtNHX4 was responsive to salt stress and abscisic acid. Experiments with CFP-AtNHX4 fusion protein indicated that AtNHX4 is vacuolar localized. The nhx4 mutant showed enhanced tolerance to salt stress, and lower Na + content under high NaCl stress compared with wild-type plants. Furthermore, heterologous expression of AtNHX4 in Escherichia coli BL21 rendered the transformants hypersensitive to NaCl. Deletion of the hydrophilic C-terminus of AtNHX4 dramatically increased the hypersensitivity of transformants, indicating that AtNHX4 may function in Na + homeostasis in plant cell, and its C-terminus plays a role in regulating the AtNHX4 activity.

Knock-out of Arabidopsis AtNHX4 gene enhances tolerance to salt stress

Energy Technology Data Exchange (ETDEWEB)

Li, Hong-Tao; Liu, Hua; Gao, Xiao-Shu [Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032 (China); Zhang, Hongxia, E-mail: hxzhang@sippe.ac.cn [Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032 (China)

2009-05-08

AtNHX4 belongs to the monovalent cation:proton antiporter-1 (CPA1) family in Arabidopsis. Several members of this family have been shown to be critical for plant responses to abiotic stress, but little is known on the biological functions of AtNHX4. Here, we provide the evidence that AtNHX4 plays important roles in Arabidopsis responses to salt stress. Expression of AtNHX4 was responsive to salt stress and abscisic acid. Experiments with CFP-AtNHX4 fusion protein indicated that AtNHX4 is vacuolar localized. The nhx4 mutant showed enhanced tolerance to salt stress, and lower Na{sup +} content under high NaCl stress compared with wild-type plants. Furthermore, heterologous expression of AtNHX4 in Escherichia coli BL21 rendered the transformants hypersensitive to NaCl. Deletion of the hydrophilic C-terminus of AtNHX4 dramatically increased the hypersensitivity of transformants, indicating that AtNHX4 may function in Na{sup +} homeostasis in plant cell, and its C-terminus plays a role in regulating the AtNHX4 activity.

Cell-Based Phenotyping Reveals QTL for Membrane Potential Maintenance Associated with Hypoxia and Salinity Stress Tolerance in Barley

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Muhammad B. Gill

2017-11-01

Full Text Available Waterlogging and salinity are two major abiotic stresses that hamper crop production world-wide resulting in multibillion losses. Plant abiotic stress tolerance is conferred by many interrelated mechanisms. Amongst these, the cell’s ability to maintain membrane potential (MP is considered to be amongst the most crucial traits, a positive relationship between the ability of plants to maintain highly negative MP and its tolerance to both salinity and waterlogging stress. However, no attempts have been made to identify quantitative trait loci (QTL conferring this trait. In this study, the microelectrode MIFE technique was used to measure the plasma membrane potential of epidermal root cells of 150 double haploid (DH lines of barley (Hordeum vulgare L. from a cross between a Chinese landrace TX9425 and Japanese malting cultivar Naso Nijo under hypoxic conditions. A major QTL for the MP in the epidermal root cells in hypoxia-exposed plants was identified. This QTL was located on 2H, at a similar position to the QTL for waterlogging and salinity tolerance reported in previous studies. Further analysis confirmed that MP showed a significant contribution to both waterlogging and salinity tolerance. The fact that the QTL for MP was controlled by a single major QTL illustrates the power of the single-cell phenotyping approach and opens prospects for fine mapping this QTL and thus being more effective in marker assisted selection.

Overexpression of wheat ferritin gene TaFER-5B enhances tolerance to heat stress and other abiotic stresses associated with the ROS scavenging.

Science.gov (United States)

Zang, Xinshan; Geng, Xiaoli; Wang, Fei; Liu, Zhenshan; Zhang, Liyuan; Zhao, Yue; Tian, Xuejun; Ni, Zhongfu; Yao, Yingyin; Xin, Mingming; Hu, Zhaorong; Sun, Qixin; Peng, Huiru

2017-01-14

The yield of wheat (Triticum aestivum L.), an important crop, is adversely affected by heat stress in many regions of the world. However, the molecular mechanisms underlying thermotolerance are largely unknown. A novel ferritin gene, TaFER, was identified from our previous heat stress-responsive transcriptome analysis of a heat-tolerant wheat cultivar (TAM107). TaFER was mapped to chromosome 5B and named TaFER-5B. Expression pattern analysis revealed that TaFER-5B was induced by heat, polyethylene glycol (PEG), H 2 O 2 and Fe-ethylenediaminedi(o-hydroxyphenylacetic) acid (Fe-EDDHA). To confirm the function of TaFER-5B in wheat, TaFER-5B was transformed into the wheat cultivar Jimai5265 (JM5265), and the transgenic plants exhibited enhanced thermotolerance. To examine whether the function of ferritin from mono- and dico-species is conserved, TaFER-5B was transformed into Arabidopsis, and overexpression of TaFER-5B functionally complemented the heat stress-sensitive phenotype of a ferritin-lacking mutant of Arabidopsis. Moreover, TaFER-5B is essential for protecting cells against heat stress associated with protecting cells against ROS. In addition, TaFER-5B overexpression also enhanced drought, oxidative and excess iron stress tolerance associated with the ROS scavenging. Finally, TaFER-5B transgenic Arabidopsis and wheat plants exhibited improved leaf iron content. Our results suggest that TaFER-5B plays an important role in enhancing tolerance to heat stress and other abiotic stresses associated with the ROS scavenging.

Durum wheat dehydrin (DHN-5) confers salinity tolerance to transgenic Arabidopsis plants through the regulation of proline metabolism and ROS scavenging system.

Science.gov (United States)

Saibi, Walid; Feki, Kaouthar; Ben Mahmoud, Rihem; Brini, Faiçal

2015-11-01

The wheat dehydrin (DHN-5) gives birth to salinity tolerance to transgenic Arabidopsis plants by the regulation of proline metabolism and the ROS scavenging system. Dehydrins (DHNs) are involved in plant abiotic stress tolerance. In this study, we reported that salt tolerance of transgenic Arabidopsis plants overexpressing durum wheat dehydrin (DHN-5) was closely related to the activation of the proline metabolism enzyme (P5CS) and some antioxidant biocatalysts. Indeed, DHN-5 improved P5CS activity in the transgenic plants generating a significant proline accumulation. Moreover, salt tolerance of Arabidopsis transgenic plants was accompanied by an excellent activation of antioxidant enzymes like catalase (CAT), superoxide dismutase (SOD) and peroxide dismutase (POD) and generation of a lower level of hydrogen peroxide (H2O2) in leaves compared to the wild-type plants. The enzyme activities were enhanced in these transgenic plants in the presence of exogenous proline. Nevertheless, proline accumulation was slightly reduced in transgenic plants promoting chlorophyll levels. All these results suggest the crucial role of DHN-5 in response to salt stress through the activation of enzymes implicated in proline metabolism and in ROS scavenging enzymes.

Mining Halophytes for Plant Growth-Promoting Halotolerant Bacteria to Enhance the Salinity Tolerance of Non-halophytic Crops

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Hassan Etesami

2018-02-01

Full Text Available Salinity stress is one of the major abiotic stresses limiting crop production in arid and semi-arid regions. Interest is increasing in the application of PGPRs (plant growth promoting rhizobacteria to ameliorate stresses such as salinity stress in crop production. The identification of salt-tolerant, or halophilic, PGPRs has the potential to promote saline soil-based agriculture. Halophytes are a useful reservoir of halotolerant bacteria with plant growth-promoting capabilities. Here, we review recent studies on the use of halophilic PGPRs to stimulate plant growth and increase the tolerance of non-halophytic crops to salinity. These studies illustrate that halophilic PGPRs from the rhizosphere of halophytic species can be effective bio-inoculants for promoting the production of non-halophytic species in saline soils. These studies support the viability of bioinoculation with halophilic PGPRs as a strategy for the sustainable enhancement of non-halophytic crop growth. The potential of this strategy is discussed within the context of ensuring sustainable food production for a world with an increasing population and continuing climate change. We also explore future research needs for using halotolerant PGPRs under salinity stress.

The use of molecular approaches in overcoming salinity stress in potato plants (abstract)

International Nuclear Information System (INIS)

Hmida-Sayari, A.; Jaoura, S.; Gargouri-Bouzid, R.

2005-01-01

Proline is known as compatible osmolyte accumulated by plant cells in response to salt and drought stresses. It is supposed to be an osmoprotectant involved in the protection of cellular structures under osmotic stress. Therefore, in an attempt to increase salt tolerance in potato, a pyrroline-5-carboxylate synthetase (P5CS) cDNA. Arabidopsis thaliana was transferred to potato plants via Agrobacterium-mediated transformation. This enzyme is responsible for conversion of glutamate to delta-pyrroline-5-carboxylate that is reduced to Proline. The resulting transgenic potato plants showed an important increase in Pro production levels compared to non-transgenic plants. This Proline accumulation was particularly enhanced in the presence of salt up to 100 mM NaCl. The transgenic potato plants showed also an improved tolerance to salinity through an increase of the tuber yield. Indeed the potato tuber yield in such transgenic lines was much less altered than in the non-transgenic plants. (author)