Utilizing genetic diversity in the desert watermelon citrullus colocynthis for enhancing watermelon cultivars for resistance to biotic and abiotic stress

Science.gov (United States)

Wide genetic diversity exists among the desert watermelon Citrullus colocynthis (L.) Schrad. (CC) accessions collected in the deserts of northern Africa, the Middle East, and Asia. Because of their resistance to biotic and abiotic stresses, there can be a viable source of genes used for enhancing wa...

Current trends in genetic manipulations to enhance abiotic and ...

African Journals Online (AJOL)

Hitherto, tolerant plants were mainly produced by classical breeding techniques. Success in breeding for better adapted varieties to abiotic and biotic stresses depends on the concerted efforts of various research domains including plant and cell physiology, molecular biology, genetics and breeding. However, such process ...

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.

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

Directory of Open Access Journals (Sweden)

Venkategowda Ramegowda

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

Nitrogen fertility and abiotic stresses management in cotton crop: a review.

Science.gov (United States)

Khan, Aziz; Tan, Daniel Kean Yuen; Afridi, Muhammad Zahir; Luo, Honghai; Tung, Shahbaz Atta; Ajab, Mir; Fahad, Shah

2017-06-01

This review outlines nitrogen (N) responses in crop production and potential management decisions to ameliorate abiotic stresses for better crop production. N is a primary constituent of the nucleotides and proteins that are essential for life. Production and application of N fertilizers consume huge amounts of energy, and excess is detrimental to the environment. Therefore, increasing plant N use efficiency (NUE) is important for the development of sustainable agriculture. NUE has a key role in crop yield and can be enhanced by controlling loss of fertilizers by application of humic acid and natural polymers (hydrogels), having high water-holding capacity which can improve plant performance under field conditions. Abiotic stresses such as waterlogging, drought, heat, and salinity are the major limitations for successful crop production. Therefore, integrated management approaches such as addition of aminoethoxyvinylglycine (AVG), the film antitranspirant (di-1-p-menthene and pinolene) nutrients, hydrogels, and phytohormones may provide novel approaches to improve plant tolerance against abiotic stress-induced damage. Moreover, for plant breeders and molecular biologists, it is a challenge to develop cotton cultivars that can tolerate plant abiotic stresses while having high potential NUE for the future.

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.

Silencing of dehydrin CaDHN1 diminishes tolerance to multiple abiotic stresses in Capsicum annuum L.

Science.gov (United States)

Chen, Ru-gang; Jing, Hua; Guo, Wei-li; Wang, Shu-Bin; Ma, Fang; Pan, Bao-Gui; Gong, Zhen-Hui

2015-12-01

We cloned a dehydrins gene CaDHN1 from pepper and the expression of CaDHN1 was markedly upregulated by cold, salt, osmotic stresses and salicylic acid (SA) treatment. Dehydrins (DHNs) are a subfamily of group 2 late embryogenesis-abundant (LEA) proteins that are thought to play an important role in enhancing abiotic stress tolerance in plants. In this study, a DHN EST (Expressed Sequence Tag) was obtained from 6 to 8 true leaves seedlings of pepper cv P70 (Capsicum annuum L.) by our laboratory. However, the DHN gene in pepper was not well characterized. According to this EST sequence, we isolated a DHN gene, designated as CaDHN1, and investigated the response and expression of this gene under various stresses. Our results indicated that CaDHN1 has the DHN-specific and conserved K- and S- domain and encodes 219 amino acids. Phylogenetic analysis showed that CaDHN1 belonged to the SKn subgroup. Tissue expression profile analysis revealed that CaDH N1 was expressed predominantly in fruits and flowers. The expression of CaDHN1 was markedly upregulated in response to cold, salt, osmotic stresses and salicylic acid (SA) treatment, but no significant change by abscisic acid (ABA) and heavy metals treatment. Loss of function of CaDHN1 using the virus-induced gene silencing (VIGS) technique led to decreased tolerance to cold-, salt- and osmotic-induced stresses. Overall, these results suggest that CaDHN1 plays an important role in regulating the abiotic stress resistance in pepper plants.

Ectopic Expression of Pumpkin NAC Transcription Factor CmNAC1 Improves Multiple Abiotic Stress Tolerance in Arabidopsis

Directory of Open Access Journals (Sweden)

Haishun Cao

2017-11-01

Full Text Available Drought, cold and salinity are the major environmental stresses that limit agricultural productivity. NAC transcription factors regulate the stress response in plants. Pumpkin (Cucurbita moschata is an important cucurbit vegetable crop and it has strong resistance to abiotic stress; however, the biological functions of stress-related NAC genes in this crop are largely unknown. This study reports the function of CmNAC1, a stress-responsive pumpkin NAC domain protein. The CmNAC1-GFP fusion protein was transiently expressed in tobacco leaves for subcellular localization analysis, and we found that CmNAC1 is localized in the nucleus. Transactivation assay in yeast cells revealed that CmNAC1 functions as a transcription activator, and its transactivation domain is located in the C-terminus. CmNAC1 was ubiquitously expressed in different organs, and its transcript was induced by salinity, cold, dehydration, H2O2, and abscisic acid (ABA treatment. Furthermore, the ectopic expression (EE of CmNAC1 in Arabidopsis led to ABA hypersensitivity and enhanced tolerance to salinity, drought and cold stress. In addition, five ABA-responsive elements were enriched in CmNAC1 promoter. The CmNAC1-EE plants exhibited different root architecture, leaf morphology, and significantly high concentration of ABA compared with WT Arabidopsis under normal conditions. Our results indicated that CmNAC1 is a critical factor in ABA signaling pathways and it can be utilized in transgenic breeding to improve the abiotic stress tolerance of crops.

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.

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

Directory of Open Access Journals (Sweden)

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.

The Arabidopsis PLAT domain protein1 is critically involved in abiotic stress tolerance

DEFF Research Database (Denmark)

Hyun, Tae Kyung; van der Graaff, Eric; Albacete, Alfonso

2014-01-01

. Abiotic stress treatments induced PLAT1 expression and caused expansion of its expression domain. The ABF/ABRE transcription factors, which are positive mediators of abscisic acid signalling, activate PLAT1 promoter activity in transactivation assays and directly bind to the ABRE elements located...... in this promoter in electrophoretic mobility shift assays. This suggests that PLAT1 represents a novel downstream target of the abscisic acid signalling pathway. Thus, we showed that PLAT1 critically functions as positive regulator of abiotic stress tolerance, but also is involved in regulating plant growth...

ABIOTIC DEHALOGENATION OF 1,2-DICHLOROETHANE AND 1,2-DIBROMETHANE IN AQUEOUS SOLUTION CONTAINING HYDROGEN SULFIDE

Science.gov (United States)

The detection of significant levels of halogenated ali- phatic contaminants in groundwater resources in the U- nited States (1, 2) has spurred a considerable effort to understand the various mechanisms-both microbiological and abiotic-by which these compounds may be trans- formed...

Column study of enhanced Cr(VI) removal and longevity by coupled abiotic and biotic processes using Fe0 and mixed anaerobic culture.

Science.gov (United States)

Zhong, Jiawei; Yin, Weizhao; Li, Yongtao; Li, Ping; Wu, Jinhua; Jiang, Gangbiao; Gu, Jingjing; Liang, Hao

2017-10-01

In this study, Fe 0 and mixed anaerobic culture were integrated in one column to investigate the coupled abiotic and biotic effects on hexa-valent chromium (Cr(VI)) removal and column longevity with an abiotic Fe 0 column in the control experiments. According to the breakthrough study, a slower Cr(VI) breakthrough rate of 0.19 cm/PV was observed in the biotic Fe 0 column whereas the value in the abiotic Fe 0 column was 0.30 cm/PV, resulting in 64% longer life-span and 62% higher Cr(VI) removal capacity in the biotic Fe 0 column than the abiotic one. The solid phase characterization by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) confirmed that this enhancement was attributed to the higher consumption of iron and greater production of diverse reactive minerals (e.g., green rust, magnetite and lepidocrocite) induced by the synergistic interaction of Fe 0 and anaerobic culture, providing more reactive sites for Cr(VI) adsorption, reduction and co-precipitation. Furthermore, the decreasing breakthrough rates and growing iron corrosion along the biotic Fe 0 column demonstrated an inhomogeneous distribution of reactive zones in the column and its latter 3/5 section was considered to be the most reactive area for Cr(VI) removal. These results indicate that the inoculation of microorganisms in Fe 0 -based permeable reactive barriers will enable this technology a higher removal capacity and longer life-span for the remediation of Cr(VI)-contaminated groundwater. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Arabidopsis PLAT domain protein1 promotes abiotic stress tolerance and growth in tobacco

Czech Academy of Sciences Publication Activity Database

Hyun, T.K.; Albacete, A.; van der Graaff, E.; Eom, S. H.; Großkinsky, D.K.; Böhm, H.; Janschek, U.; Rim, Y.; Ali, W.; Kim, S.Y.; Roitsch, Thomas

2015-01-01

Roč. 24, č. 4 (2015), s. 651-663 ISSN 0962-8819 Institutional support: RVO:67179843 Keywords : Abiotic stress * Biotic stress * Plant growth * AtPLAT1 gene * Tobacco Subject RIV: EH - Ecology, Behaviour Impact factor: 2.054, year: 2015

Abiotic stresses affect Trichoderma harzianum T39-induced resistance to downy mildew in grapevine.

Science.gov (United States)

Roatti, Benedetta; Perazzolli, Michele; Gessler, Cesare; Pertot, Ilaria

2013-12-01

Enhancement of plant defense through the application of resistance inducers seems a promising alternative to chemical fungicides for controlling crop diseases but the efficacy can be affected by abiotic factors in the field. Plants respond to abiotic stresses with hormonal signals that may interfere with the mechanisms of induced systemic resistance (ISR) to pathogens. In this study, we exposed grapevines to heat, drought, or both to investigate the effects of abiotic stresses on grapevine resistance induced by Trichoderma harzianum T39 (T39) to downy mildew. Whereas the efficacy of T39-induced resistance was not affected by exposure to heat or drought, it was significantly reduced by combined abiotic stresses. Decrease of leaf water potential and upregulation of heat-stress markers confirmed that plants reacted to abiotic stresses. Basal expression of defense-related genes and their upregulation during T39-induced resistance were attenuated by abiotic stresses, in agreement with the reduced efficacy of T39. The evidence reported here suggests that exposure of crops to abiotic stress should be carefully considered to optimize the use of resistance inducers, especially in view of future global climate changes. Expression analysis of ISR marker genes could be helpful to identify when plants are responding to abiotic stresses, in order to optimize treatments with resistance inducers in field.

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

Directory of Open Access Journals (Sweden)

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.

Involvement of co-repressor LUH and the adapter proteins SLK1 and SLK2 in the regulation of abiotic stress response genes in Arabidopsis.

Science.gov (United States)

Shrestha, Barsha; Guragain, Bhuwan; Sridhar, Vaniyambadi V

2014-02-24

During abiotic stress many genes that are important for growth and adaptation to stress are expressed at elevated levels. However, the mechanisms that keep the stress responsive genes from expressing under non stress conditions remain elusive. Recent genetic characterization of the co-repressor LEUNIG_HOMOLOG (LUH) and transcriptional adaptor proteins SEUSS-LIKE1 (SLK1) and SLK2 have been proposed to function redundantly in diverse developmental processes; however their function in the abiotic stress response is unknown. Moreover, the molecular functions of LUH, SLK1 and SLK2 remain obscure. Here, we show the molecular function of LUH, SLK1 and SLK2 and the role of this complex in the abiotic stress response. The luh, slk1 and slk2 mutant plants shows enhanced tolerance to salt and osmotic stress conditions. SLK1 and SLK2 interact physically with the LUFS domain in LUH forming SLK1-LUH and SLK2-LUH co-repressor complexes to inhibit the transcription. LUH has repressor activity, whereas SLK1 and SLK2 function as adaptors to recruit LUH, which in turn recruits histone deacetylase to the target sequences to repress transcription. The stress response genes RD20, MYB2 and NAC019 are expressed at elevated levels in the luh, slk1 and slk2 mutant plants. Furthermore, these stress response genes are associated with decreased nucleosome density and increased acetylation levels at H3K9 and H3K14 in the luh, slk1 and slk2 mutant plants. Our results indicate that SLK1, SLK2 and LUH form a co-repressor complex. LUH represses by means of an epigenetic process involving histone modification to facilitate the condensation of chromatin thus preventing transcription at the target genes.

Pre-mRNA splicing repression triggers abiotic stress signaling in plants

KAUST Repository

Ling, Yu

2016-09-24

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

Pre-mRNA splicing repression triggers abiotic stress signaling in plants

KAUST Repository

Ling, Yu; Alshareef, Sahar; Butt, Haroon; Lozano-Juste, Jorge; Li, Lixin; Galal, Aya A.; Moustafa, Ahmed; Momin, Afaque Ahmad Imtiyaz; Tashkandi, Manal; Richardson, Dale N.; Fujii, Hiroaki; Arold, Stefan T.; Rodriguez, Pedro L.; Duque, Paula; Mahfouz, Magdy M.

2016-01-01

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

MicroRNA Regulation of Abiotic Stress Response in 7B-1 Male-Sterile Tomato Mutant

Czech Academy of Sciences Publication Activity Database

Omidvar, Vahid; Mohorianu, I.; Dalmay, T.; Fellner, Martin

2015-01-01

Roč. 8, č. 3 (2015), s. 1-13 ISSN 1940-3372 R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : 7B-1 mutant * abiotic stress * miRNAs Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.509, year: 2015

Overexpression of an AP2/ERF Type Transcription Factor OsEREBP1 Confers Biotic and Abiotic Stress Tolerance in Rice.

Directory of Open Access Journals (Sweden)

V Jisha

Full Text Available AP2/ERF-type transcription factors regulate important functions of plant growth and development as well as responses to environmental stimuli. A rice AP2/ERF transcription factor, OsEREBP1 is a downstream component of a signal transduction pathway in a specific interaction between rice (Oryza sativa and its bacterial pathogen, Xoo (Xanthomonas oryzae pv. oryzae. Constitutive expression of OsEREBP1 in rice driven by maize ubiquitin promoter did not affect normal plant growth. Microarray analysis revealed that over expression of OsEREBP1 caused increased expression of lipid metabolism related genes such as lipase and chloroplastic lipoxygenase as well as several genes related to jasmonate and abscisic acid biosynthesis. PR genes, transcription regulators and Aldhs (alcohol dehydrogenases implicated in abiotic stress and submergence tolerance were also upregulated in transgenic plants. Transgenic plants showed increase in endogenous levels of α-linolenate, several jasmonate derivatives and abscisic acid but not salicylic acid. Soluble modified GFP (SmGFP-tagged OsEREBP1 was localized to plastid nucleoids. Comparative analysis of non-transgenic and OsEREBP1 overexpressing genotypes revealed that OsEREBP1 attenuates disease caused by Xoo and confers drought and submergence tolerance in transgenic rice. Our results suggest that constitutive expression of OsEREBP1 activates the jasmonate and abscisic acid signalling pathways thereby priming the rice plants for enhanced survival under abiotic or biotic stress conditions. OsEREBP1 is thus, a good candidate gene for engineering plants for multiple stress tolerance.

Transcriptional Regulation of Arabidopsis MIR168a and ARGONAUTE1 Homeostasis in Abscisic Acid and Abiotic Stress Responses1[W

Science.gov (United States)

Li, Wei; Cui, Xiao; Meng, Zhaolu; Huang, Xiahe; Xie, Qi; Wu, Heng; Jin, Hailing; Zhang, Dabing; Liang, Wanqi

2012-01-01

The accumulation of a number of small RNAs in plants is affected by abscisic acid (ABA) and abiotic stresses, but the underlying mechanisms are poorly understood. The miR168-mediated feedback regulatory loop regulates ARGONAUTE1 (AGO1) homeostasis, which is crucial for gene expression modulation and plant development. Here, we reveal a transcriptional regulatory mechanism by which MIR168 controls AGO1 homeostasis during ABA treatment and abiotic stress responses in Arabidopsis (Arabidopsis thaliana). Plants overexpressing MIR168a and the AGO1 loss-of-function mutant ago1-27 display ABA hypersensitivity and drought tolerance, while the mir168a-2 mutant shows ABA hyposensitivity and drought hypersensitivity. Both the precursor and mature miR168 were induced under ABA and several abiotic stress treatments, but no obvious decrease for the target of miR168, AGO1, was shown under the same conditions. However, promoter activity analysis indicated that AGO1 transcription activity was increased under ABA and drought treatments, suggesting that transcriptional elevation of MIR168a is required for maintaining a stable AGO1 transcript level during the stress response. Furthermore, we showed both in vitro and in vivo that the transcription of MIR168a is directly regulated by four abscisic acid-responsive element (ABRE) binding factors, which bind to the ABRE cis-element within the MIR168a promoter. This ABRE motif is also found in the promoter of MIR168a homologs in diverse plant species. Our findings suggest that transcriptional regulation of miR168 and posttranscriptional control of AGO1 homeostasis may play an important and conserved role in stress response and signal transduction in plants. PMID:22247272

Unraveling the role of fungal symbionts in plant abiotic stress tolerance

Science.gov (United States)

Singh, Lamabam Peter

2011-01-01

Fungal symbionts have been found to be associated with every plant studied in the natural ecosystem, where they colonize and reside entirely or partially in the internal tissues of their host plant. Fungal endophytes can express/form a range of different lifestyle/relationships with different host including symbiotic, mutualistic, commensalistic and parasitic in response to host genotype and environmental factors. In mutualistic association fungal endophyte can enhance growth, increase reproductive success and confer biotic and abiotic stress tolerance to its host plant. Since abiotic stress such as, drought, high soil salinity, heat, cold, oxidative stress and heavy metal toxicity is the common adverse environmental conditions that affect and limit crop productivity worldwide. It may be a promising alternative strategy to exploit fungal endophytes to overcome the limitations to crop production brought by abiotic stress. There is an increasing interest in developing the potential biotechnological applications of fungal endophytes for improving plant stress tolerance and sustainable production of food crops. Here we have described the fungal symbioses, fungal symbionts and their role in abiotic stress tolerance. A putative mechanism of stress tolerance by symbionts has also been covered. PMID:21512319

The Promoter of AtUSP Is Co-regulated by Phytohormones and Abiotic Stresses in Arabidopsis thaliana.

Science.gov (United States)

Bhuria, Monika; Goel, Parul; Kumar, Sanjay; Singh, Anil K

2016-01-01

Universal stress proteins (USPs) are known to be expressed in response to various abiotic stresses in a wide variety of organisms, such as bacteria, archaebacteria, protists, algae, fungi, plants, and animals. However, in plants, biological function of most of the USPs still remains obscure. In the present study, Arabidopsis USP gene ( AtUSP ) showed induction in response to abscisic acid (ABA) and various abiotic stresses viz . heat, dehydration, salt, osmotic, and cold stresses. Additionally, in silico analysis of AtUSP promoter identified several cis -elements responsive to phytohormones and abiotic stresses such as ABRE, ERE, DRE, and HSE, etc. To functionally validate the AtUSP promoter, the 1115 bp region of promoter was characterized under phytohormone and abiotic stress treatments. Deletion analysis of promoter was carried out by cloning the full length promoter (D0) and its three 5' deletion derivatives, D1 (964 bp), D2 (660 bp), and D3 (503 bp) upstream of the β-glucuronidase (GUS) reporter gene, which were then stably transformed in Arabidopsis plants. The AtUSP promoter (D0) showed minimal activity under non-stress conditions which was enhanced in response to phytohormone treatments (ABA and ACC) and abiotic stresses such as dehydration, heat, cold, salt, and osmotic stresses. The seedlings harboring D1 and D2 deletion fragments showed constitutive GUS expression even under control condition with increased activity almost under all the treatments. However, D3 seedlings exhibited complete loss of activity under control condition with induction under ACC treatment, dehydration, heat, oxidative, salt, and osmotic stresses. Thus, present study clearly showed that AtUSP promoter is highly inducible by phytohormones and multiple abiotic stresses and it can be exploited as stress inducible promoter to generate multi-stress tolerant crops with minimal effects on their other important traits.

Enhanced biotic and abiotic transformation of Cr(vi) by quinone-reducing bacteria/dissolved organic matter/Fe(iii) in anaerobic environment.

Science.gov (United States)

Huang, Bin; Gu, Lipeng; He, Huan; Xu, Zhixiang; Pan, Xuejun

2016-09-14

This study investigated the simultaneous transformation of Cr(vi) via a closely coupled biotic and abiotic pathway in an anaerobic system of quinone-reducing bacteria/dissolved organic matters (DOM)/Fe(iii). Batch studies were conducted with quinone-reducing bacteria to assess the influences of sodium formate (NaFc), electron shuttling compounds (DOM) and the Fe(iii) on Cr(vi) reduction rates as these chemical species are likely to be present in the environment during in situ bioremediation. Results indicated that the concentration of sodium formate and anthraquinone-2-sodium sulfonate (AQS) had apparently an effect on Cr(vi) reduction. The fastest decrease in rate for incubation supplemented with 5 mM sodium formate and 0.8 mM AQS showed that Fe(iii)/DOM significantly promoted the reduction of Cr(vi). Presumably due to the presence of more easily utilizable sodium formate, DOM and Fe(iii) have indirect Cr(vi) reduction capability. The coexisting cycles of Fe(ii)/Fe(iii) and DOM(ox)/DOM(red) exhibited a higher redox function than the individual cycle, and their abiotic coupling action can significantly enhance Cr(vi) reduction by quinone-reducing bacteria.

Abiotic and bioaugmented granular activated carbon for the treatment of 1,4-dioxane-contaminated water.

Science.gov (United States)

Myers, Michelle A; Johnson, Nicholas W; Marin, Erick Zerecero; Pornwongthong, Peerapong; Liu, Yun; Gedalanga, Phillip B; Mahendra, Shaily

2018-06-04

1,4-Dioxane is a probable human carcinogen and an emerging contaminant that has been detected in surface water and groundwater resources. Many conventional water treatment technologies are not effective for the removal of 1,4-dioxane due to its high water solubility and chemical stability. Biological degradation is a potentially low-cost, energy-efficient approach to treat 1,4-dioxane-contaminated waters. Two bacterial strains, Pseudonocardia dioxanivorans CB1190 (CB1190) and Mycobacterium austroafricanum JOB5 (JOB5), have been previously demonstrated to break down 1,4-dioxane through metabolic and co-metabolic pathways, respectively. However, both CB1190 and JOB5 have been primarily studied in laboratory planktonic cultures, while most environmental microbes grow in biofilms on surfaces. Another treatment technology, adsorption, has not historically been considered an effective means of removing 1,4-dioxane due to the contaminant's low K oc and K ow values. We report that the granular activated carbon (GAC), Norit 1240, is an adsorbent with high affinity for 1,4-dioxane as well as physical dimensions conducive to attached bacterial growth. In abiotic batch reactor studies, 1,4-dioxane adsorption was reversible to a large extent. By bioaugmenting GAC with 1,4-dioxane-degrading microbes, the adsorption reversibility was minimized while achieving greater 1,4-dioxane removal when compared with abiotic GAC (95-98% reduction of initial 1,4-dioxane as compared to an 85-89% reduction of initial 1,4-dioxane, respectively). Bacterial attachment and viability was visualized using fluorescence microscopy and confirmed by amplification of taxonomic genes by quantitative polymerase chain reaction (qPCR) and an ATP assay. Filtered samples of industrial wastewater and contaminated groundwater were also tested in the bioaugmented GAC reactors. Both CB1190 and JOB5 demonstrated 1,4-dioxane removal greater than that of the abiotic adsorbent controls. This study suggests that

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

KAUST Repository

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

Abiotic ozone and oxygen in atmospheres similar to prebiotic Earth

International Nuclear Information System (INIS)

Domagal-Goldman, Shawn D.; Segura, Antígona; Claire, Mark W.; Robinson, Tyler D.; Meadows, Victoria S.

2014-01-01

The search for life on planets outside our solar system will use spectroscopic identification of atmospheric biosignatures. The most robust remotely detectable potential biosignature is considered to be the detection of oxygen (O 2 ) or ozone (O 3 ) simultaneous to methane (CH 4 ) at levels indicating fluxes from the planetary surface in excess of those that could be produced abiotically. Here we use an altitude-dependent photochemical model with the enhanced lower boundary conditions necessary to carefully explore abiotic O 2 and O 3 production on lifeless planets with a wide variety of volcanic gas fluxes and stellar energy distributions. On some of these worlds, we predict limited O 2 and O 3 buildup, caused by fast chemical production of these gases. This results in detectable abiotic O 3 and CH 4 features in the UV-visible, but no detectable abiotic O 2 features. Thus, simultaneous detection of O 3 and CH 4 by a UV-visible mission is not a strong biosignature without proper contextual information. Discrimination between biological and abiotic sources of O 2 and O 3 is possible through analysis of the stellar and atmospheric context—particularly redox state and O atom inventory—of the planet in question. Specifically, understanding the spectral characteristics of the star and obtaining a broad wavelength range for planetary spectra should allow more robust identification of false positives for life. This highlights the importance of wide spectral coverage for future exoplanet characterization missions. Specifically, discrimination between true and false positives may require spectral observations that extend into infrared wavelengths and provide contextual information on the planet's atmospheric chemistry.

The wheat transcription factor, TabHLH39, improves tolerance to multiple abiotic stressors in transgenic plants.

Science.gov (United States)

Zhai, Yiqian; Zhang, Lichao; Xia, Chuan; Fu, Silu; Zhao, Guangyao; Jia, Jizeng; Kong, Xiuying

2016-05-13

Although bHLH transcription factors play important roles regulating plant development and abiotic stress response and tolerance, few functional studies have been performed in wheat. In this study, we isolated and characterized a bHLH gene, TabHLH39, from wheat. The TabHLH39 gene is located on wheat chromosome 5DL, and the protein localized to the nucleus and activated transcription. TabHLH39 showed variable expression in roots, stems, leaves, glumes, pistils and stamens and was induced by polyethylene glycol, salt and cold treatments. Further analysis revealed that TabHLH39 overexpression in Arabidopsis significantly enhanced tolerance to drought, salt and freezing stress during the seedling stage, which was also demonstrated by enhanced abiotic stress-response gene expression and changes to several physiological indices. Therefore, TabHLH39 has potential in transgenic breeding applications to improve abiotic stress tolerance in crops. Copyright © 2016 Elsevier Inc. All rights reserved.

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

KAUST Repository

Hirt, Heribert

2017-07-27

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 environmental stress conditions.

The shifting influence of abiotic drivers during landslide succession in Puerto Rico

Science.gov (United States)

L. R. Walker; A. B. Shiels; P. J. Bellingham; A. D. Sparrow; N. Fetcher; F. H. Landau; D. J. Lodge

2013-01-01

Summary 1. Abiotic variables are critical drivers of succession in most primary seres, but how their influence on biota changes over time is rarely examined. Landslides provide good model systems for examining abiotic influences because they are spatially and temporally heterogeneous habitats with distinct abiotic and biotic gradients and post-landslide erosion. 2. In...

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

Abiotic ozone and oxygen in atmospheres similar to prebiotic Earth

Energy Technology Data Exchange (ETDEWEB)

Domagal-Goldman, Shawn D. [Planetary Environments Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Segura, Antígona; Claire, Mark W.; Robinson, Tyler D.; Meadows, Victoria S., E-mail: shawn.goldman@nasa.gov [NASA Astrobiology Institute—Virtual Planetary Laboratory (United States)

2014-09-10

The search for life on planets outside our solar system will use spectroscopic identification of atmospheric biosignatures. The most robust remotely detectable potential biosignature is considered to be the detection of oxygen (O{sub 2}) or ozone (O{sub 3}) simultaneous to methane (CH{sub 4}) at levels indicating fluxes from the planetary surface in excess of those that could be produced abiotically. Here we use an altitude-dependent photochemical model with the enhanced lower boundary conditions necessary to carefully explore abiotic O{sub 2} and O{sub 3} production on lifeless planets with a wide variety of volcanic gas fluxes and stellar energy distributions. On some of these worlds, we predict limited O{sub 2} and O{sub 3} buildup, caused by fast chemical production of these gases. This results in detectable abiotic O{sub 3} and CH{sub 4} features in the UV-visible, but no detectable abiotic O{sub 2} features. Thus, simultaneous detection of O{sub 3} and CH{sub 4} by a UV-visible mission is not a strong biosignature without proper contextual information. Discrimination between biological and abiotic sources of O{sub 2} and O{sub 3} is possible through analysis of the stellar and atmospheric context—particularly redox state and O atom inventory—of the planet in question. Specifically, understanding the spectral characteristics of the star and obtaining a broad wavelength range for planetary spectra should allow more robust identification of false positives for life. This highlights the importance of wide spectral coverage for future exoplanet characterization missions. Specifically, discrimination between true and false positives may require spectral observations that extend into infrared wavelengths and provide contextual information on the planet's atmospheric chemistry.

Transcriptional regulation of Arabidopsis MIR168a and argonaute1 homeostasis in abscisic acid and abiotic stress responses.

Science.gov (United States)

Li, Wei; Cui, Xiao; Meng, Zhaolu; Huang, Xiahe; Xie, Qi; Wu, Heng; Jin, Hailing; Zhang, Dabing; Liang, Wanqi

2012-03-01

The accumulation of a number of small RNAs in plants is affected by abscisic acid (ABA) and abiotic stresses, but the underlying mechanisms are poorly understood. The miR168-mediated feedback regulatory loop regulates ARGONAUTE1 (AGO1) homeostasis, which is crucial for gene expression modulation and plant development. Here, we reveal a transcriptional regulatory mechanism by which MIR168 controls AGO1 homeostasis during ABA treatment and abiotic stress responses in Arabidopsis (Arabidopsis thaliana). Plants overexpressing MIR168a and the AGO1 loss-of-function mutant ago1-27 display ABA hypersensitivity and drought tolerance, while the mir168a-2 mutant shows ABA hyposensitivity and drought hypersensitivity. Both the precursor and mature miR168 were induced under ABA and several abiotic stress treatments, but no obvious decrease for the target of miR168, AGO1, was shown under the same conditions. However, promoter activity analysis indicated that AGO1 transcription activity was increased under ABA and drought treatments, suggesting that transcriptional elevation of MIR168a is required for maintaining a stable AGO1 transcript level during the stress response. Furthermore, we showed both in vitro and in vivo that the transcription of MIR168a is directly regulated by four abscisic acid-responsive element (ABRE) binding factors, which bind to the ABRE cis-element within the MIR168a promoter. This ABRE motif is also found in the promoter of MIR168a homologs in diverse plant species. Our findings suggest that transcriptional regulation of miR168 and posttranscriptional control of AGO1 homeostasis may play an important and conserved role in stress response and signal transduction in plants.

Novel perspectives for the engineering of abiotic stress tolerance in plants.

Science.gov (United States)

Cabello, Julieta V; Lodeyro, Anabella F; Zurbriggen, Matias D

2014-04-01

Adverse environmental conditions pose serious limitations to agricultural production. Classical biotechnological approaches towards increasing abiotic stress tolerance focus on boosting plant endogenous defence mechanisms. However, overexpression of regulatory elements or effectors is usually accompanied by growth handicap and yield penalties due to crosstalk between developmental and stress-response networks. Herein we offer an overview on novel strategies with the potential to overcome these limitations based on the engineering of regulatory systems involved in the fine-tuning of the plant response to environmental hardships, including post-translational modifications, small RNAs, epigenetic control of gene expression and hormonal networks. The development and application of plant synthetic biology tools and approaches will add new functionalities and perspectives to genetic engineering programs for enhancing abiotic stress tolerance. Copyright © 2013 Elsevier Ltd. All rights reserved.

Understanding the Posttranscriptional Regulation of Plant Responses to Abiotic Stress

KAUST Repository

AlShareef, Sahar A.

2017-06-01

Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and biotic and abiotic stresses. Recent work showed that AS is pervasive across plant species, with more than 60% of intron-containing genes producing different isoforms. Mammalian cell-based assays have discovered various AS small-molecule inhibitors that perturb splicing and thereby provide invaluable tools for use as chemical probes to uncover the molecular underpinnings of splicing regulation and as potential anticancer compounds. Here, I show that the macrolide Pladienolide B (PB) and herboxidiene (GEX1A) inhibits both constitutive and alternative splicing, mimics an abiotic stress signal, and activates the abscisic acid (ABA) pathway in plants. Moreover, PB and GEX1A activate genome-wide transcriptional patterns involved in abiotic stress responses in plants. PB and GEX1A treatment triggered the ABA signaling pathway, activated ABA-inducible promoters, and led to stomatal closure. Interestingly, PB and GEX1A elicited similar cellular changes, including alterations in the patterns of transcription and splicing, suggesting that these compounds might target the same spliceosome complex in plant cells. This work establishes PB and GEX1A as potent splicing inhibitors in plants that can be used to probe the assembly, dynamics, and molecular functions of the spliceosome and to study the interplay between splicing stress and abiotic stresses, as well as having potential biotechnological applications.

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

Characterization of Arabidopsis thaliana FLAVONOL SYNTHASE 1 (FLS1) -overexpression plants in response to abiotic stress.

Science.gov (United States)

Nguyen, Nguyen Hoai; Kim, Jun Hyeok; Kwon, Jaeyoung; Jeong, Chan Young; Lee, Wonje; Lee, Dongho; Hong, Suk-Whan; Lee, Hojoung

2016-06-01

Flavonoids are an important group of secondary metabolites that are involved in plant growth and contribute to human health. Many studies have focused on the biosynthesis pathway, biochemical characters, and biological functions of flavonoids. In this report, we showed that overexpression of FLS1 (FLS1-OX) not only altered seed coat color (resulting in a light brown color), but also affected flavonoid accumulation. Whereas fls1-3 mutants accumulated higher anthocyanin levels, FLS1-OX seedlings had lower levels than those of the wild-type. Besides, shoot tissues of FLS1-OX plants exhibited lower flavonol levels than those of the wild-type. However, growth performance and abiotic stress tolerance of FLS1-OX, fls1-3, and wild-type plants were not significantly different. Taken together, FLS1 can be manipulated (i.e., silenced or overexpressed) to redirect the flavonoid biosynthetic pathway toward anthocyanin production without negative effects on plant growth and development. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

The C-terminal region (640-967) of Arabidopsis CPL1 interacts with the abiotic stress- and ABA-responsive transcription factors

International Nuclear Information System (INIS)

Bang, Woo Young; Kim, Se Won; Jeong, In Sil; Koiwa, Hisashi; Bahk, Jeong Dong

2008-01-01

Proteins in CPL1 family are unique to plants and contain a phosphatase catalytic domain and double-stranded RNA (dsRNA)-binding motifs (DRMs) in a single peptide. Though DRMs are important for the function of Arabidopsis CPL1 in vivo, the role of CPL1 DRM has been obscure. We have isolated two transcription factors, ANAC019 (At1g52890) and AtMYB3 (At1g22640), which specifically interact with the C-terminal region (640-967) of AtCPL1 containing two DRMs. Detailed interaction analysis indicated that AtMYB3 specifically interacted with the first DRM but not with the second DRM in CPL1 C-terminal fragment. GFP-fusion analysis indicated that AtMYB3 localized in nuclei-like CPL1, and its expression is induced by abiotic stress and ABA treatment. These results suggest that AtMYB3 function in abiotic stress signaling in concert with CPL1

Comparison of U and Np uptake on biogenic and abiotic ferrihydrite by XAFS

International Nuclear Information System (INIS)

Krawczyk-Baersch, Evelyn; Schmeide, Katja; Kvashnina, Kristina O.; Rossberg, Andre; Scheinost, Andreas C.

2017-01-01

XAS spectra of U and Np sorption biogenic ferrihydrite samples were compared to abiotic samples. The k 3 -weighted χ-spectrum and its Fourier-transform of the studied biogenic ferrihydrite sample bears close resemblance to the bidentate edge-sharing innersphere sorption 1 E complex, which is the main sorption species on abiotic ferrihydrite. Based on the shell fit analysis, the distances of the coordination shells U-O eq , U-O ax , and U-Fe are similar to those determined for abiotic ferrihydrite samples.

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

Directory of Open Access Journals (Sweden)

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.

NAC transcription factor JUNGBRUNNEN1 enhances drought tolerance in tomato

KAUST Repository

Thirumalaikumar, Venkatesh P.

2017-06-22

Water deficit (drought stress) massively restricts plant growth and the yield of crops; reducing the deleterious effects of drought is therefore of high agricultural relevance. Drought triggers diverse cellular processes including the inhibition of photosynthesis, the accumulation of cell-damaging reactive oxygen species, and gene expression reprogramming, besides others. Transcription factors (TF) are central regulators of transcriptional reprogramming and expression of many TF genes is affected by drought, including members of the NAC family. Here, we identify the NAC factor JUNGBRUNNEN1 (JUB1) as a regulator of drought tolerance in tomato (Solanum lycopersicum). Expression of tomato JUB1 (SlJUB1) is enhanced by various abiotic stresses, including drought. Inhibiting SlJUB1 by virus-induced gene silencing drastically lowers drought tolerance concomitant with an increase in ion leakage, an elevation of hydrogen peroxide (H2 O2 ) levels, and a decrease of the expression of various drought-responsive genes. In contrast, overexpression of AtJUB1 from Arabidopsis thaliana increases drought tolerance in tomato, alongside with a higher relative leaf water content during drought and reduced H2 O2 levels. AtJUB1 was previously shown to stimulate expression of DREB2A, a TF involved in drought responses, and of the DELLA genes GAI and RGL1. We show here that SlJUB1 similarly controls the expression of the tomato orthologs SlDREB1, SlDREB2, and SlDELLA. Furthermore, AtJUB1 directly binds to the promoters of SlDREB1, SlDREB2 and SlDELLA in tomato. Our study highlights JUB1 as a transcriptional regulator of drought tolerance and suggests considerable conservation of the abiotic stress-related gene regulatory networks controlled by this NAC factor between Arabidopsis and tomato. This article is protected by copyright. All rights reserved.

Comparison of U and Np uptake on biogenic and abiotic ferrihydrite by XAFS

Energy Technology Data Exchange (ETDEWEB)

Krawczyk-Baersch, Evelyn [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry; Schmeide, Katja [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Kvashnina, Kristina O.; Rossberg, Andre; Scheinost, Andreas C. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Molecular Structures

2017-06-01

XAS spectra of U and Np sorption biogenic ferrihydrite samples were compared to abiotic samples. The k{sup 3}-weighted χ-spectrum and its Fourier-transform of the studied biogenic ferrihydrite sample bears close resemblance to the bidentate edge-sharing innersphere sorption {sup 1}E complex, which is the main sorption species on abiotic ferrihydrite. Based on the shell fit analysis, the distances of the coordination shells U-O{sub eq}, U-O{sub ax}, and U-Fe are similar to those determined for abiotic ferrihydrite samples.

SERDP ER-1376 Enhancement of In Situ Bioremediation of Energetic Compounds by Coupled Abiotic/Biotic Processes:Final Report for 2004 - 2006

Energy Technology Data Exchange (ETDEWEB)

Szecsody, James E.; Comfort, Steve; Fredrickson, Herbert L.; Boparai, Hardiljeet K.; Devary, Brooks J.; Thompson, Karen T.; Phillips, Jerry L.; Crocker, Fiona H.; Girvin, Donald C.; Resch, Charles T.; Shea, Patrick; Fischer, Ashley E.; Durkin, Lisa M.

2007-08-07

This project was initiated by SERDP to quantify processes and determine the effectiveness of abiotic/biotic mineralization of energetics (RDX, HMX, TNT) in aquifer sediments by combinations of biostimulation (carbon, trace nutrient additions) and chemical reduction of sediment to create a reducing environment. Initially it was hypothesized that a balance of chemical reduction of sediment and biostimulation would increase the RDX, HMX, and TNT mineralization rate significantly (by a combination of abiotic and biotic processes) so that this abiotic/biotic treatment may be a more efficient for remediation than biotic treatment alone in some cases. Because both abiotic and biotic processes are involved in energetic mineralization in sediments, it was further hypothesized that consideration for both abiotic reduction and microbial growth was need to optimize the sediment system for the most rapid mineralization rate. Results show that there are separate optimal abiotic/biostimulation aquifer sediment treatments for RDX/HMX and for TNT. Optimal sediment treatment for RDX and HMX (which have chemical similarities and similar degradation pathways) is mainly chemical reduction of sediment, which increased the RDX/HMX mineralization rate 100 to150 times (relative to untreated sediment), with additional carbon or trace nutrient addition, which increased the RDX/HMX mineralization rate an additional 3 to 4 times. In contrast, the optimal aquifer sediment treatment for TNT involves mainly biostimulation (glucose addition), which stimulates a TNT/glucose cometabolic degradation pathway (6.8 times more rapid than untreated sediment), degrading TNT to amino-intermediates that irreversibly sorb (i.e., end product is not CO2). The TNT mass migration risk is minimized by these transformation reactions, as the triaminotoluene and 2,4- and 2,6-diaminonitrotoluene products that irreversibly sorb are no longer mobile in the subsurface environment. These transformation rates are increased

ROS-mediated abiotic stress-induced programmed cell death in plants

Directory of Open Access Journals (Sweden)

Veselin ePetrov

2015-02-01

Full Text Available During the course of their ontogenesis, plants are continuously exposed to a large variety of abiotic stress factors which can damage tissues and jeopardize the survival of the organism unless properly countered. While animals can simply escape and thus evade stressors, plants as sessile organisms have developed complex strategies to withstand them. When the intensity of a detrimental factor is high, one of the defense programs employed by plants is the induction of programmed cell death (PCD. This is an active, genetically controlled process which is initiated to isolate and remove damaged tissues thereby ensuring the survival of the organism. The mechanism of PCD induction usually includes an increase in the levels of reactive oxygen species (ROS which are utilized as mediators of the stress signal. Abiotic stress-induced PCD is not only a process of fundamental biological importance, but also of considerable interest to agricultural practice as it has the potential to significantly influence crop yield. Therefore, numerous scientific enterprises have focused on elucidating the mechanisms leading to and controlling PCD in response to adverse conditions in plants. This knowledge may help to develop novel strategies to obtain more resilient crop varieties with improved tolerance and enhanced productivity. The aim of the present review is to summarize the recent advances in research on ROS-induced PCD related to abiotic stress and the role of the organelles in the process.

Safety aspects of genetically modified crops with abiotic stress tolerance

NARCIS (Netherlands)

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

2014-01-01

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

Utilizing genetic resources and precision agriculture to enhance resistance to biotic and abiotic stress in watermelon

Science.gov (United States)

Originally from Africa, watermelon is a staple crop in South Carolina and rich source of important phytochemicals that promote human health. As a result of many years of domestication and selection for desired fruit quality, modern watermelon cultivars are susceptible to biotic and abiotic stress. T...

Abiotic dechlorination in rock matrices impacted by long-term exposure to TCE.

Science.gov (United States)

Schaefer, Charles E; Towne, Rachael M; Lippincott, David R; Lacombe, Pierre J; Bishop, Michael E; Dong, Hailiang

2015-01-01

Field and laboratory tests were performed to evaluate the abiotic reaction of trichloroethene (TCE) in sedimentary rock matrices. Hydraulically conductive fractures, and the rock directly adjacent to the hydraulically conductive fractures, within a historically contaminated TCE bedrock aquifer were used as the basis for this study. These results were compared to previous work using rock that had not been exposed to TCE (Schaefer et al., 2013) to assess the impact of long-term TCE exposure on the abiotic dechlorination reaction, as the longevity of these reactions after long-term exposure to TCE was hitherto unknown. Results showed that potential abiotic TCE degradation products, including ethane, ethene, and acetylene, were present in the conductive fractures. Using minimally disturbed slices of rock core at and near the fracture faces, laboratory testing on the rocks confirmed that abiotic dechlorination reactions between the rock matrix and TCE were occurring. Abiotic daughter products measured in the laboratory under controlled conditions were consistent with those measured in the conductive fractures, except that propane also was observed as a daughter product. TCE degradation measured in the laboratory was well described by a first order rate constant through the 118-d study. Observed bulk first-order TCE degradation rate constants within the rock matrix were 1.3×10(-8) s(-1). These results clearly show that abiotic dechlorination of TCE is occurring within the rock matrix, despite decades of exposure to TCE. Furthermore, these observed rates of TCE dechlorination are expected to have a substantial impact on TCE migration and uptake/release from rock matrices. Copyright © 2014 Elsevier Ltd. All rights reserved.

Relationships between biotic and abiotic factors and regeneration of chestnut oak, white oak, and northern red oak

Science.gov (United States)

Songlin Fei; Kim C. Steiner; James C. Finley; Marc E. McDill

2003-01-01

A series of substantial field surveys of 38 mixed-oak stands in central Pennsylvania were carried out during 1996-2000. All the stands were surveyed 1 year prior to harvest, and 16 stands have been surveyed 1 year after harvest. Three abiotic factors at stand scale, four abiotic factors at plot scale, and two biotic factors and one abiotic factor at subplot scale was...

Resistance Responses of Potato to Vesicular-Arbuscular Mycorrhizal Fungi under Varying Abiotic Phosphorus Levels.

Science.gov (United States)

McArthur, D A; Knowles, N R

1992-09-01

In mycorrhizal symbioses, susceptibility of a host plant to infection by fungi is influenced by environmental factors, especially the availability of soil phosphorus. This study describes morphological and biochemical details of interactions between a vesicular-arbuscular mycorrhizal (VAM) fungus and potato (Solanum tuberosum L. cv Russet Burbank) plants, with a particular focus on the physiological basis for P-induced resistance of roots to infection. Root infection by the VAM fungus Glomus fasciculatum ([Thaxt. sensu Gerdemann] Gerdemann and Trappe) was extensive for plants grown with low abiotic P supply, and plant biomass accumulation was enhanced by the symbiosis. The capacity of excised roots from P-deficient plants to produce ethylene in the presence or absence of exogenous 1-amino cyclopropane-1-carboxylic acid (ACC) was markedly reduced by VAM infection. This apparent inhibition of ACC oxidase (ACC(ox)) activity was localized to areas containing infected roots, as demonstrated in split-root studies. Furthermore, leachate from VAM roots contained a potent water-soluble inhibitor of ethylene generation from exogenous ACC by nonmycorrhizal (NM) roots. The leachate from VAM-infected roots had a higher concentration of phenolics, relative to that from NM roots. Moreover, the rates of ethylene formation and phenolic concentration in leachates from VAM roots were inversely correlated, suggesting that this inhibitor may be of a phenolic nature. The specific activity of extracellular peroxidase recovered in root leachates was not stimulated by VAM infection, although activity on a fresh weight basis was significantly enhanced, reflecting the fact that VAM roots had higher protein content than NM roots. Polyphenol oxidase activity of roots did not differ between NM and VAM roots. These results characterize the low resistance response of P-deficient plants to VAM infection. When plants were grown with higher abiotic P supply, the relative benefit of the VAM symbiosis

Functional Characterization of TaSnRK2.8 Promoter in Response to Abiotic Stresses by Deletion Analysis in Transgenic Arabidopsis

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Hongying Zhang

2017-07-01

Full Text Available Drought, salinity, and cold are the major factors limiting wheat quality and productivity; it is thus highly desirable to characterize the abiotic-stress-inducible promoters suitable for the genetic improvement of plant resistance. The sucrose non-fermenting 1-related protein kinase 2 (SnRK2 family genes show distinct regulatory properties in response to abiotic stresses. The present study characterized the approximately 3000-bp upstream sequence (the 313 bp upstream of the ATG was the transcription start site of the Triticum aestivum TaSnRK2.8 promoter under abscisic acid (ABA and abiotic stresses. Four different-length 5′ deletion fragments of TaSnRK2.8 promoter were fused with the GUS reporter gene and transformed into Arabidopsis. Tissue expression analysis showed that the TaSnRK2.8 promoter region from position -1481 to -821 contained the stalk-specific elements, and the region from position -2631 to -1481 contained the leaf- and root-specific elements. In the ABA-treated seedlings, the deletion analysis showed that the TaSnRK2.8 promoter region from position -821 to -2631 contained ABA response elements. The abiotic stress responses of the TaSnRK2.8 promoter derivatives demonstrated that they harbored abiotic-stress response elements: the region from position -821 to -408 harbored the osmotic-stress response elements, whereas the region from position -2631 to -1481 contained the positive regulatory motifs and the region from position -1481 to -821 contained the leaf- and stalk-specific enhancers. Further deletion analysis of the promoter region from position -821 to -408 indicated that a 125-bp region from position -693 to -568 was required to induce an osmotic-stress response. These results contribute to a better understanding of the molecular mechanisms of TaSnRK2.8 in response to abiotic stresses, and the TaSnRK2.8 promoter seems to be a candidate for regulating the expression of abiotic stress response genes in transgenic plants.

Abscisic Acid and Abiotic Stress Signaling

OpenAIRE

Tuteja, Narendra

2007-01-01

Abiotic stress is severe environmental stress, which impairs crop production on irrigated land worldwide. Overall, the susceptibility or tolerance to the stress in plants is a coordinated action of multiple stress responsive genes, which also cross-talk with other components of stress signal transduction pathways. Plant responses to abiotic stress can be determined by the severity of the stress and by the metabolic status of the plant. Abscisic acid (ABA) is a phytohormone critical for plant ...

Resilience of cereal crops to abiotic stress: A review | Ahmad ...

African Journals Online (AJOL)

In the last century, conventional selection and breeding program proved to be highly effective in improving crops against abiotic stresses. Therefore, breeding for abiotic stress tolerance in crop plants should be given high research priority as abiotic stresses are the main factor negatively affecting crop growth and ...

Abiotic transformation of estrogens in synthetic municipal wastewater: An alternative for treatment?

Energy Technology Data Exchange (ETDEWEB)

Marfil-Vega, Ruth [School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, 701 Engineering Research Center, Cincinnati, OH 45221-0071 (United States); Suidan, Makram T., E-mail: Makram.Suidan@uc.ed [School of Energy, Environmental, Biological and Medical Engineering, University of Cincinnati, 701 Engineering Research Center, Cincinnati, OH 45221-0071 (United States); Mills, Marc A. [USEPA, Office of Research and Development, National Risk Management Research Laboratory, Cincinnati, OH 45268 (United States)

2010-11-15

The abiotic transformation of estrogens, including estrone (E1), estradiol (E2), estriol (E3) and ethinylestradiol (EE2), in the presence of model vegetable matter was confirmed in this study. Batch experiments were performed to model the catalytic conversion of E1, E2, E3 and EE2 in synthetic wastewater. Greater than 80% reduction in the parent compounds was achieved for each target chemical after 72 h with the remaining concentration distributed between aqueous and solid phases as follows: 13% and 7% for E1, 10% and 2% for E2, 6% and 2% for E3, and 8% and 3% for EE2, respectively. Testosterone, androstenedione and progesterone were also monitored in this study, and their concentrations were found to be in agreement with initially spiked amount. Data collected under laboratory conditions provided the basis for implementing new abiotic wastewater treatment technologies that use inexpensive materials. - Abiotic transformation of estrogens in wastewater matrices can be harnessed for improving their removal from the environment.

Abiotic transformation of estrogens in synthetic municipal wastewater: An alternative for treatment?

International Nuclear Information System (INIS)

Marfil-Vega, Ruth; Suidan, Makram T.; Mills, Marc A.

2010-01-01

The abiotic transformation of estrogens, including estrone (E1), estradiol (E2), estriol (E3) and ethinylestradiol (EE2), in the presence of model vegetable matter was confirmed in this study. Batch experiments were performed to model the catalytic conversion of E1, E2, E3 and EE2 in synthetic wastewater. Greater than 80% reduction in the parent compounds was achieved for each target chemical after 72 h with the remaining concentration distributed between aqueous and solid phases as follows: 13% and 7% for E1, 10% and 2% for E2, 6% and 2% for E3, and 8% and 3% for EE2, respectively. Testosterone, androstenedione and progesterone were also monitored in this study, and their concentrations were found to be in agreement with initially spiked amount. Data collected under laboratory conditions provided the basis for implementing new abiotic wastewater treatment technologies that use inexpensive materials. - Abiotic transformation of estrogens in wastewater matrices can be harnessed for improving their removal from the environment.

The Abiotic Depletion Potential: Background, Updates, and Future

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Lauran van Oers

2016-03-01

Full Text Available Depletion of abiotic resources is a much disputed impact category in life cycle assessment (LCA. The reason is that the problem can be defined in different ways. Furthermore, within a specified problem definition, many choices can still be made regarding which parameters to include in the characterization model and which data to use. This article gives an overview of the problem definition and the choices that have been made when defining the abiotic depletion potentials (ADPs for a characterization model for abiotic resource depletion in LCA. Updates of the ADPs since 2002 are also briefly discussed. Finally, some possible new developments of the impact category of abiotic resource depletion are suggested, such as redefining the depletion problem as a dilution problem. This means taking the reserves in the environment and the economy into account in the reserve parameter and using leakage from the economy, instead of extraction rate, as a dilution parameter.

Abiotic methane formation during experimental serpentinization of olivine.

Science.gov (United States)

McCollom, Thomas M

2016-12-06

Fluids circulating through actively serpentinizing systems are often highly enriched in methane (CH 4 ). In many cases, the CH 4 in these fluids is thought to derive from abiotic reduction of inorganic carbon, but the conditions under which this process can occur in natural systems remain unclear. In recent years, several studies have reported abiotic formation of CH 4 during experimental serpentinization of olivine at temperatures at or below 200 °C. However, these results seem to contradict studies conducted at higher temperatures (300 °C to 400 °C), where substantial kinetic barriers to CH 4 synthesis have been observed. Here, the potential for abiotic formation of CH 4 from dissolved inorganic carbon during olivine serpentinization is reevaluated in a series of laboratory experiments conducted at 200 °C to 320 °C. A 13 C-labeled inorganic carbon source was used to unambiguously determine the origin of CH 4 generated in the experiments. Consistent with previous high-temperature studies, the results indicate that abiotic formation of CH 4 from reduction of dissolved inorganic carbon during the experiments is extremely limited, with nearly all of the observed CH 4 derived from background sources. The results indicate that the potential for abiotic synthesis of CH 4 in low-temperature serpentinizing environments may be much more limited than some recent studies have suggested. However, more extensive production of CH 4 was observed in one experiment performed under conditions that allowed an H 2 -rich vapor phase to form, suggesting that shallow serpentinization environments where a separate gas phase is present may be more favorable for abiotic synthesis of CH 4 .

Column study of enhanced Cr(VI) removal and longevity by coupled abiotic and biotic processes using Fe⁰ and mixed anaerobic culture

DEFF Research Database (Denmark)

Zhong, Jiawei; Yin, Weizhao; Li, Yongtao

2017-01-01

In this study, Fe(0) and mixed anaerobic culture were integrated in one column to investigate the coupled abiotic and biotic effects on hexa-valent chromium (Cr(VI)) removal and column longevity with an abiotic Fe(0) column in the control experiments. According to the breakthrough study, a slower...

Abiotic stress miRNomes in the Triticeae

OpenAIRE

Alptekin, Burcu; Langridge, Peter; Budak, Hikmet

2016-01-01

The continued growth in world population necessitates increases in both the quantity and quality of agricultural production. Triticeae members, particularly wheat and barley, make an important contribution to world food reserves by providing rich sources of carbohydrate and protein. These crops are grown over diverse production environments that are characterized by a range of environmental or abiotic stresses. Abiotic stresses such as drought, heat, salinity, or nutrient deficiencies and tox...

Roles of abiotic losses, microbes, plant roots, and root exudates on phytoremediation of PAHs in a barren soil.

Science.gov (United States)

Sun, Tian-Ran; Cang, Long; Wang, Quan-Ying; Zhou, Dong-Mei; Cheng, Jie-Min; Xu, Hui

2010-04-15

Phytoremediation is an emerging technology for the remediation of polycyclic aromatic hydrocarbons (PAHs). In this study, pot experiments were conducted to evaluate the efficacy of phytoremediation of phenanthrene and pyrene in a typical low organic matter soil (3.75 g kg(-1)), and the contribution proportions of abiotic losses, microbes, plant roots, and root exudates were ascertained during the PAHs dissipation. The results indicated that contribution of abiotic losses from this soil was high both for phenanthrene (83.4%) and pyrene (57.2%). The contributions of root-exudates-enhanced biodegradation of phenanthrene (15.5%) and pyrene (21.3%) were higher than those of indigenous microbial degradation. The role of root exudates on dissipation of phenanthrene and pyrene was evident in this experiment. By the way, with the increasing of ring numbers in PAHs structures, the root-exudates-enhanced degradation became more and more important. BIOLOG-ECO plate analysis indicated that microbial community structure of the soil receiving root exudates had changed. The removal efficiency and substrate utilization rate in the treatment with plant roots were lower than the treatment only with root exudates, which suggested that possible competition between roots and microbes for nutrients had occurred in a low organic matter soil. 2009. Published by Elsevier B.V.

Protection of the Abiotic Environment

International Nuclear Information System (INIS)

Michel, R.; Hutmacher, K. E.; Landfermann, H. H.

2004-01-01

Environmental protection against the dangers arising from ionizing radiation, radioactive materials, and other harmful substances is more than to avoid acute dangers or risks for humans or for non-human living organisms. To allow for a sustainable development the abiotic part of the environment must not be neglected in concepts of environmental protection. The environmental impact of some selected long-lived anthropogenic radionuclides is used to exemplify adverse effects for which a unified approach is needed. To this end, indicators are needed for the assessment of the human impact on the abiotic environment which allows to compare different human actions with respect to sustainability and to choose appropriate measures in the competition for a sustainable development. Such indicators have to account for the dynamics of the different environmental compartments. Using the long-lived radionuclides 14C, 36Cl, 85Kr, and 129I as examples, the importance to consider dynamical models and ecological lifetimes in quantifications of the human impact on the environment is emphasized. Particular problems arise from the natural occurrences and variability of radionuclides and other harmful substances. Suitable indicators for the assessment of human impact on the abiotic compartments air, water, and soil are discussed. (Author) 18 refs

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.

Science.gov (United States)

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.

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

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Arjun Sham

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

Polyamines and abiotic stress in plants: A complex relationship

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Rakesh eMinocha

2014-05-01

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

Abiotic synthesis of organic compounds from carbon disulfide under hydrothermal conditions.

Science.gov (United States)

Rushdi, Ahmed I; Simoneit, Bernd R T

2005-12-01

Abiotic formation of organic compounds under hydrothermal conditions is of interest to bio, geo-, and cosmochemists. Oceanic sulfur-rich hydrothermal systems have been proposed as settings for the abiotic synthesis of organic compounds. Carbon disulfide is a common component of magmatic and hot spring gases, and is present in marine and terrestrial hydrothermal systems. Thus, its reactivity should be considered as another carbon source in addition to carbon dioxide in reductive aqueous thermosynthesis. We have examined the formation of organic compounds in aqueous solutions of carbon disulfide and oxalic acid at 175 degrees C for 5 and 72 h. The synthesis products from carbon disulfide in acidic aqueous solutions yielded a series of organic sulfur compounds. The major compounds after 5 h of reaction included dimethyl polysulfides (54.5%), methyl perthioacetate (27.6%), dimethyl trithiocarbonate (6.8%), trithianes (2.7%), hexathiepane (1.4%), trithiolanes (0.8%), and trithiacycloheptanes (0.3%). The main compounds after 72 h of reaction consisted of trithiacycloheptanes (39.4%), pentathiepane (11.6%), tetrathiocyclooctanes (11.5%), trithiolanes (10.6%), tetrathianes (4.4%), trithianes (1.2%), dimethyl trisulfide (1.1%), and numerous minor compounds. It is concluded that the abiotic formation of aliphatic straight-chain and cyclic polysulfides is possible under hydrothermal conditions and warrants further studies.

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

Directory of Open Access Journals (Sweden)

Weijuan Fan

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

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

Science.gov (United States)

Shi, Haitao; Ye, Tiantian; Chan, Zhulong

2013-10-01

As a gaseous molecule, hydrogen sulfide (H2S) has been recently found to be involved in plant responses to multiple abiotic stress. In this study, salt (150 and 300 mM NaCl), osmotic (15% and 30% PEG6000) and cold (4 °C) stress treatments induced accumulation of endogenous H2S level, indicating that H2S might play a role in bermudagrass responses to salt, osmotic and cold stresses. Exogenous application of H2S donor (sodium hydrosulfide, NaHS) conferred improved salt, osmotic and freezing stress tolerances in bermudagrass, which were evidenced by decreased electrolyte leakage and increased survival rate under stress conditions. Additionally, NaHS treatment alleviated the reactive oxygen species (ROS) burst and cell damage induced by abiotic stress, via modulating metabolisms of several antioxidant enzymes [catalase (CAT), peroxidase (POD) and GR (glutathione reductase)] and non-enzymatic glutathione antioxidant pool and redox state. Moreover, exogenous NaHS treatment led to accumulation of osmolytes (proline, sucrose and soluble total sugars) in stressed bermudagrass plants. Taken together, all these data indicated the protective roles of H2S in bermudagrass responses to salt, osmotic and freezing stresses, via activation of the antioxidant response and osmolyte accumulation. These findings might be applicable to grass and crop engineering to improve abiotic stress tolerance. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Differential expression of poplar sucrose nonfermenting1-related protein kinase 2 genes in response to abiotic stress and abscisic acid.

Science.gov (United States)

Yu, Xiang; Takebayashi, Arika; Demura, Taku; Ohtani, Misato

2017-09-01

Knowledge on the responses of woody plants to abiotic stress can inform strategies to breed improved tree varieties and to manage tree species for environmental conservation and the production of lignocellulosic biomass. In this study, we examined the expression patterns of poplar (Populus trichocarpa) genes encoding members of the sucrose nonfermenting1-related protein kinase 2 (SnRK2) family, which are core components of the abiotic stress response. The P. trichocarpa genome contains twelve SnRK2 genes (PtSnRK2.1- PtSnRK2.12) that can be divided into three subclasses (I-III) based on the structures of their encoded kinase domains. We found that PtSnRK2s are differentially expressed in various organs. In MS medium-grown plants, all of the PtSnRK2 genes were significantly upregulated in response to abscisic acid (ABA) treatment, whereas osmotic and salt stress treatments induced only some (four and seven, respectively) of the PtSnRK2 genes. By contrast, soil-grown plants showed increased expression of most PtSnRK2 genes under drought and salt treatments, but not under ABA treatment. In soil-grown plants, drought stress induced SnRK2 subclass II genes in all tested organs (leaves, stems, and roots), whereas subclass III genes tended to be upregulated in leaves only. These results suggest that the PtSnRK2 genes are involved in abiotic stress responses, are at least partially activated by ABA, and show organ-specific responses.

A Wheat SIMILAR TO RCD-ONE Gene Enhances Seedling Growth and Abiotic Stress Resistance by Modulating Redox Homeostasis and Maintaining Genomic Integrity[C][W

Science.gov (United States)

Liu, Shuantao; Liu, Shuwei; Wang, Mei; Wei, Tiandi; Meng, Chen; Wang, Meng; Xia, Guangmin

2014-01-01

Plant growth inhibition is a common response to salinity. Under saline conditions, Shanrong No. 3 (SR3), a bread wheat (Triticum aestivum) introgression line, performs better than its parent wheat variety Jinan 177 (JN177) with respect to both seedling growth and abiotic stress tolerance. Furthermore, the endogenous reactive oxygen species (ROS) was also elevated in SR3 relative to JN177. The SR3 allele of sro1, a gene encoding a poly(ADP ribose) polymerase (PARP) domain protein, was identified to be crucial for both aspects of its superior performance. Unlike RADICAL-INDUCED CELL DEATH1 and other Arabidopsis thaliana SIMILAR TO RCD-ONE (SRO) proteins, sro1 has PARP activity. Both the overexpression of Ta-sro1 in wheat and its heterologous expression in Arabidopsis promote the accumulation of ROS, mainly by enhancing the activity of NADPH oxidase and the expression of NAD(P)H dehydrogenase, in conjunction with the suppression of alternative oxidase expression. Moreover, it promotes the activity of ascorbate-GSH cycle enzymes and GSH peroxidase cycle enzymes, which regulate ROS content and cellular redox homeostasis. sro1 is also found to be involved in the maintenance of genomic integrity. We show here that the wheat SRO has PARP activity; such activity could be manipulated to improve the growth of seedlings exposed to salinity stress by modulating redox homeostasis and maintaining genomic stability. PMID:24443520

Designing cooperatively folded abiotic uni- and multimolecular helix bundles

Science.gov (United States)

de, Soumen; Chi, Bo; Granier, Thierry; Qi, Ting; Maurizot, Victor; Huc, Ivan

2018-01-01

Abiotic foldamers, that is foldamers that have backbones chemically remote from peptidic and nucleotidic skeletons, may give access to shapes and functions different to those of peptides and nucleotides. However, design methodologies towards abiotic tertiary and quaternary structures are yet to be developed. Here we report rationally designed interactional patterns to guide the folding and assembly of abiotic helix bundles. Computational design facilitated the introduction of hydrogen-bonding functionalities at defined locations on the aromatic amide backbones that promote cooperative folding into helix-turn-helix motifs in organic solvents. The hydrogen-bond-directed aggregation of helices not linked by a turn unit produced several thermodynamically and kinetically stable homochiral dimeric and trimeric bundles with structures that are distinct from the designed helix-turn-helix. Relative helix orientation within the bundles may be changed from parallel to tilted on subtle solvent variations. Altogether, these results prefigure the richness and uniqueness of abiotic tertiary structure behaviour.

Abscisic Acid and abiotic stress signaling.

Science.gov (United States)

Tuteja, Narendra

2007-05-01

Abiotic stress is severe environmental stress, which impairs crop production on irrigated land worldwide. Overall, the susceptibility or tolerance to the stress in plants is a coordinated action of multiple stress responsive genes, which also cross-talk with other components of stress signal transduction pathways. Plant responses to abiotic stress can be determined by the severity of the stress and by the metabolic status of the plant. Abscisic acid (ABA) is a phytohormone critical for plant growth and development and plays an important role in integrating various stress signals and controlling downstream stress responses. Plants have to adjust ABA levels constantly in responce to changing physiological and environmental conditions. To date, the mechanisms for fine-tuning of ABA levels remain elusive. The mechanisms by which plants respond to stress include both ABA-dependent and ABA-independent processes. Various transcription factors such as DREB2A/2B, AREB1, RD22BP1 and MYC/MYB are known to regulate the ABA-responsive gene expression through interacting with their corrosponding cis-acting elements such as DRE/CRT, ABRE and MYCRS/MYBRS, respectively. Understanding these mechanisms is important to improve stress tolerance in crops plants. This article first describes the general pathway for plant stress response followed by roles of ABA and transcription factors in stress tolerance including the regulation of ABA biosynthesis.

Life without water: cross-resistance of anhydrobiotic cell line to abiotic stresses

Science.gov (United States)

Gusev, Oleg

2016-07-01

Anhydrobiosis is an intriguing phenomenon of natural ability of some organisms to resist water loss. The larvae of Polypedilum vanderplanki, the sleeping chironomid is the largest and most complex anhydrobionts known to date. The larvae showed ability to survive variety of abiotic stresses, including outer space environment. Recently cell line (Pv11) derived from the embryonic mass of the chironomid was established. Initially sensitive to desiccation cells, are capable to "induced" anhydrobiosis, when the resistance to desiccation can be developed by pre-treatment of the cells with trehalose followed by quick desiccation. We have further conducted complex analysis of the whole genome transcription response of Pv11 cells to different abiotic stresses, including oxidative stress and irradiation. Comparative analysis showed that the gene set, responsible for formation of desiccation resistance (ARID regions in the genome) is also activated in response to other types of stresses and likely to contribute to general enhancing of the resistance of the cells to harsh environment. We have further demonstrated that the cells are able to protect recombinant proteins from harmful effect of desiccation

Poaceae vs. Abiotic Stress: Focus on Drought and Salt Stress, Recent Insights and Perspectives

Directory of Open Access Journals (Sweden)

Simone Landi

2017-07-01

Full Text Available Poaceae represent the most important group of crops susceptible to abiotic stress. This large family of monocotyledonous plants, commonly known as grasses, counts several important cultivated species, namely wheat (Triticum aestivum, rice (Oryza sativa, maize (Zea mays, and barley (Hordeum vulgare. These crops, notably, show different behaviors under abiotic stress conditions: wheat and rice are considered sensitive, showing serious yield reduction upon water scarcity and soil salinity, while barley presents a natural drought and salt tolerance. During the green revolution (1940–1960, cereal breeding was very successful in developing high-yield crops varieties; however, these cultivars were maximized for highest yield under optimal conditions, and did not present suitable traits for tolerance under unfavorable conditions. The improvement of crop abiotic stress tolerance requires a deep knowledge of the phenomena underlying tolerance, to devise novel approaches and decipher the key components of agricultural production systems. Approaches to improve food production combining both enhanced water use efficiency (WUE and acceptable yields are critical to create a sustainable agriculture in the future. This paper analyzes the latest results on abiotic stress tolerance in Poaceae. In particular, the focus will be directed toward various aspects of water deprivation and salinity response efficiency in Poaceae. Aspects related to cell wall metabolism will be covered, given the importance of the plant cell wall in sensing environmental constraints and in mediating a response; the role of silicon (Si, an important element for monocots' normal growth and development, will also be discussed, since it activates a broad-spectrum response to different exogenous stresses. Perspectives valorizing studies on landraces conclude the survey, as they help identify key traits for breeding purposes.

GhWRKY25, a group I WRKY gene from cotton, confers differential tolerance to abiotic and biotic stresses in transgenic Nicotiana benthamiana.

Science.gov (United States)

Liu, Xiufang; Song, Yunzhi; Xing, Fangyu; Wang, Ning; Wen, Fujiang; Zhu, Changxiang

2016-09-01

WRKY transcription factors are involved in various processes, ranging from plant growth to abiotic and biotic stress responses. Group I WRKY members have been rarely reported compared with group II or III members, particularly in cotton (Gossypium hirsutum). In this study, a group I WRKY gene, namely, GhWRKY25, was cloned from cotton and characterized. Expression analysis revealed that GhWRKY25 can be induced or deduced by the treatments of abiotic stresses and multiple defense-related signaling molecules. Overexpression of GhWRKY25 in Nicotiana benthamiana reduced plant tolerance to drought stress but enhanced tolerance to salt stress. Moreover, more MDA and ROS accumulated in transgenic plants after drought treatment with lower activities of SOD, POD, and CAT. Our study further demonstrated that GhWRKY25 overexpression in plants enhanced sensitivity to the fungal pathogen Botrytis cinerea by reducing the expression of SA or ET signaling related genes and inducing the expression of genes involved in the JA signaling pathway. These results indicated that GhWRKY25 plays negative or positive roles in response to abiotic stresses, and the reduced pathogen resistance may be related to the crosstalk of the SA and JA/ET signaling pathways.

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.

Transcriptomic Profiling of the Maize (Zea mays L.) Leaf Response to Abiotic Stresses at the Seedling Stage.

Science.gov (United States)

Li, Pengcheng; Cao, Wei; Fang, Huimin; Xu, Shuhui; Yin, Shuangyi; Zhang, Yingying; Lin, Dezhou; Wang, Jianan; Chen, Yufei; Xu, Chenwu; Yang, Zefeng

2017-01-01

Abiotic stresses, including drought, salinity, heat, and cold, negatively affect maize ( Zea mays L.) development and productivity. To elucidate the molecular mechanisms of resistance to abiotic stresses in maize, RNA-seq was used for global transcriptome profiling of B73 seedling leaves exposed to drought, salinity, heat, and cold stress. A total of 5,330 differentially expressed genes (DEGs) were detected in differential comparisons between the control and each stressed sample, with 1,661, 2,019, 2,346, and 1,841 DEGs being identified in comparisons of the control with salinity, drought, heat, and cold stress, respectively. Functional annotations of DEGs suggested that the stress response was mediated by pathways involving hormone metabolism and signaling, transcription factors (TFs), very-long-chain fatty acid biosynthesis and lipid signaling, among others. Of the obtained DEGs (5,330), 167 genes are common to these four abiotic stresses, including 10 up-regulated TFs (five ERFs, two NACs, one ARF, one MYB, and one HD-ZIP) and two down-regulated TFs (one b-ZIP and one MYB-related), which suggested that common mechanisms may be initiated in response to different abiotic stresses in maize. This study contributes to a better understanding of the molecular mechanisms of maize leaf responses to abiotic stresses and could be useful for developing maize cultivars resistant to abiotic stresses.

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.

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

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Shabir H. Wani

2016-06-01

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

Support media can steer methanogenesis in the presence of phenol through biotic and abiotic effects.

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Poirier, Simon; Déjean, Sébastien; Chapleur, Olivier

2018-09-01

A wide variety of inhibitors can induce anaerobic digester disruption. To avoid performance losses, support media can be used to mitigate inhibitions. However, distinguishing the physico-chemical from the biological mechanisms of such strategies remains delicate. In this framework, the impact of 10  g/L of different types of zeolites and activated carbons (AC) on microbial community dynamics during anaerobic digestion of biowaste in the presence of 1.3 g/L of phenol was evaluated with 16 S rRNA gene sequencing. In the presence of AC, methanogenesis inhibition was rapidly removed due to a decrease of phenol concentration. This abiotic effect related to the physico-chemical properties of AC led to increased final CH4 and CO2 productions by 29-31% compared to digesters incubated without support. Interestingly, although zeolite did not adsorb phenol, final CH4 and CO2 production reached comparable levels as with AC. Nevertheless, compared to digesters incubated without support, methanogenesis lag phase duration was less reduced in the presence of zeolites (5 ± 1 days) than in the presence of activated carbons (12 ± 2 days). Both types of support induced biotic effects. AC and zeolite both allowed the preservation of the major representative archaeal genus of the non-inhibited ecosystem, Methanosarcina. By contrast, they distinctly shaped bacterial populations. OTUs belonging to class W5 became dominant at the expense of OTUs assigned to orders Clostridiales, Bacteroidales and Anaerolinales in the presence of AC. Zeolite enhanced the implantation of OTUs assigned to bacterial phylum Cloacimonetes. This study highlighted that supports can induce biotic and abiotic effects within digesters inhibited with phenol, showing potentialities to enhance anaerobic digestion stability under disrupting conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

DEFF Research Database (Denmark)

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

2013-01-01

Transcription factors (TFs) are master regulators of abiotic stress responses in plants. This review focuses on TFs from seven major TF families, known to play functional roles in response to abiotic stresses, including drought, high salinity, high osmolarity, temperature extremes...... and the phytohormone ABA. Although ectopic expression of several TFs has improved abiotic stress tolerance in plants, fine-tuning of TF expression and protein levels remains a challenge to avoid crop yield loss. To further our understanding of TFs in abiotic stress responses, emerging gene regulatory networks based...... on TFs and their direct targets genes are presented. These revealed components shared between ABA-dependent and independent signaling as well as abiotic and biotic stress signaling. Protein structure analysis suggested that TFs hubs of large interactomes have extended regions with protein intrinsic...

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

International Nuclear Information System (INIS)

Narayan, Om Prakash; Kumari, Nidhi; Rai, Lal Chand

2010-01-01

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

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

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Bo Liu

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

Identification of the AQP members involved in abiotic stress responses from Arabidopsis.

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Feng, Zhi-Juan; Xu, Sheng-Chun; Liu, Na; Zhang, Gu-Wen; Hu, Qi-Zan; Xu, Zhao-Shi; Gong, Ya-Ming

2018-03-10

Aquaporins (AQPs) constitute a highly diverse family of water channel proteins that play crucial biological functions in plant growth and development and stress physiology. In Arabidopsis, 35 AQPs are classified into four subfamilies (PIPs, TIPs, NIPs and SIPs). However, knowledge about the roles of different subfamily AQPs remains limited. Here, we explored the chromosomal location, gene structure and expression patterns of all AQPs in different tissues or under different abiotic stresses based on available microarray data. Tissue expression analysis showed that different AQPs had various expression patterns in tissues (root, leaf, flower and seed). Expression profiles under stress conditions revealed that most AQPs were responsive to osmotic, salt and drought stresses. Phenotypic and physiological identification showed that Tip2;2 loss-of-function mutant exhibited less sensitive to abiotic stresses (mannitol, NaCl and PEG) compared with wild-type, as evident by analysis of germination rate, root growth, survival rate, ion leakage, malondialdehyde (MDA) and proline contents. Mutant of TIP2;2 modulated the transcript levels of SOS1, SOS2, SOS3, DREB1A, DREB2A and P5CS1, under abiotic stress conditions. This study provides a basis for further functional identification of stress-related candidate AQPs in Arabidopsis. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrode impedance analysis of chronic tungsten microwire neural implants: understanding abiotic vs. biotic contributions

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Viswanath eSankar

2014-05-01

Full Text Available Changes in biotic and abiotic factors can be reflected in the complex impedance spectrum of the microelectrodes chronically implanted into the neural tissue. The recording surface of the tungsten electrode in vivo undergoes abiotic changes due to recording site corrosion and insulation delamination as well as biotic changes due to tissue encapsulation as a result of the foreign body immune response. We reported earlier that large changes in electrode impedance measured at 1 kHz were correlated with poor electrode functional performance, quantified through electrophysiological recordings during the chronic lifetime of the electrode. There is a need to identity the factors that contribute to the chronic impedance variation. In this work, we use numerical simulation and regression to equivalent circuit models to evaluate both the abiotic and biotic contributions to the impedance response over chronic implant duration. COMSOL® simulation of abiotic electrode morphology changes provide a possible explanation for the decrease in the electrode impedance at long implant duration while biotic changes play an important role in the large increase in impedance observed initially.

Revisiting the Role of Plant Transcription Factors in the Battle against Abiotic Stress.

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Khan, Sardar-Ali; Li, Meng-Zhan; Wang, Suo-Min; Yin, Hong-Ju

2018-05-31

Owing to diverse abiotic stresses and global climate deterioration, the agricultural production worldwide is suffering serious losses. Breeding stress-resilient crops with higher quality and yield against multiple environmental stresses via application of transgenic technologies is currently the most promising approach. Deciphering molecular principles and mining stress-associate genes that govern plant responses against abiotic stresses is one of the prerequisites to develop stress-resistant crop varieties. As molecular switches in controlling stress-responsive genes expression, transcription factors (TFs) play crucial roles in regulating various abiotic stress responses. Hence, functional analysis of TFs and their interaction partners during abiotic stresses is crucial to perceive their role in diverse signaling cascades that many researchers have continued to undertake. Here, we review current developments in understanding TFs, with particular emphasis on their functions in orchestrating plant abiotic stress responses. Further, we discuss novel molecular mechanisms of their action under abiotic stress conditions. This will provide valuable information for understanding regulatory mechanisms to engineer stress-tolerant crops.

Variations in abiotic conditions of water quality of River Osun, Osun ...

African Journals Online (AJOL)

Otoigiakih

Full Length Research Paper. Variations in abiotic conditions of water quality of River. Osun, Osun State, Nigeria. Farombi, A. G.1*, Adebayo, O. R.2, Olagunju E. O.1 and Oyekanmi A. M.2. 1Science Laboratory Technology Department, Faculty of Science, Osun State Polytechnic, Iree, Osun State, Nigeria. 2Applied Science ...

Additional insights into the adaptation of cotton plants under abiotic ...

African Journals Online (AJOL)

Abiotic stress is the primary cause of crop losses worldwide. In addition to protein coding genes, microRNAs (miRNAs) have emerged as important players in plant stress responses. Though miRNAs are key in regulating many aspects of plant developmental plasticity under abiotic stresses, very few information are available ...

The Role of MAPK Modules and ABA during Abiotic Stress Signaling

KAUST Repository

Zé licourt, Axel de; Colcombet, Jean; Hirt, Heribert

2016-01-01

To respond to abiotic stresses, plants have developed specific mechanisms that allow them to rapidly perceive and respond to environmental changes. The phytohormone abscisic acid (ABA) was shown to be a pivotal regulator of abiotic stress responses

Methane clumped isotopes in the Songliao Basin (China): New insights into abiotic vs. biotic hydrocarbon formation

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Shuai, Yanhua; Etiope, Giuseppe; Zhang, Shuichang; Douglas, Peter M. J.; Huang, Ling; Eiler, John M.

2018-01-01

Abiotic hydrocarbon gas, typically generated in serpentinized ultramafic rocks and crystalline shields, has important implications for the deep biosphere, petroleum systems, the carbon cycle and astrobiology. Distinguishing abiotic gas (produced by chemical reactions like Sabatier synthesis) from biotic gas (produced from degradation of organic matter or microbial activity) is sometimes challenging because their isotopic and molecular composition may overlap. Abiotic gas has been recognized in numerous locations on the Earth, although there are no confirmed instances where it is the dominant source of commercially valuable quantities in reservoir rocks. The deep hydrocarbon reservoirs of the Xujiaweizi Depression in the Songliao Basin (China) have been considered to host significant amounts of abiotic methane. Here we report methane clumped-isotope values (Δ18) and the isotopic composition of C1-C3 alkanes, CO2 and helium of five gas samples collected from those Xujiaweizi deep reservoirs. Some geochemical features of these samples resemble previously suggested identifiers of abiotic gas (13C-enriched CH4; decrease in 13C/12C ratio with increasing carbon number for the C1-C4 alkanes; abundant, apparently non-biogenic CO2; and mantle-derived helium). However, combining these constraints with new measurements of the clumped-isotope composition of methane and careful consideration of the geological context, suggests that the Xujiaweizi depression gas is dominantly, if not exclusively, thermogenic and derived from over-mature source rocks, i.e., from catagenesis of buried organic matter at high temperatures. Methane formation temperatures suggested by clumped-isotopes (167-213 °C) are lower than magmatic gas generation processes and consistent with the maturity of local source rocks. Also, there are no geological conditions (e.g., serpentinized ultramafic rocks) that may lead to high production of H2 and thus abiotic production of CH4 via CO2 reduction. We propose

Herboxidiene triggers splicing repression and abiotic stress responses in plants

KAUST Repository

Alshareef, Sahar

2017-03-27

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

SERDP ER-1421 Abiotic and Biotic Mechanisms Controlling In Situ Remediation of NDMA: Final Report

Energy Technology Data Exchange (ETDEWEB)

Szecsody, James E.; McKinley, James P.; Crocker, Fiona H.; Breshears, Andrew T.; Devary, Brooks J.; Fredrickson, Herbert L.; Thompson, Karen T.

2009-09-30

This laboratory-scale project was initiated to investigate in situ abiotic/biotic mineralization of NDMA. Under iron-reducing conditions, aquifer sediments showed rapid abiotic NDMA degradation to dimethylamine (DMA), nitrate, formate, and finally, CO2. These are the first reported experiments of abiotic NDMA mineralization. The NDMA reactivity of these different iron phases showed that adsorbed ferrous iron was the dominant reactive phase that promoted NDMA reduction, and other ferrous phases present (siderite, iron sulfide, magnetite, structural ferrous iron in 2:1 clays) did not promote NDMA degradation. In contrast, oxic sediments that were biostimulated with propane promoted biomineralization of NDMA by a cometabolic monooxygenase enzyme process. Other monooxygenase enzyme processes were not stimulated with methane or toluene additions, and acetylene addition did not block mineralization. Although NDMA mineralization extent was the highest in oxic, biostimulated sediments (30 to 82%, compared to 10 to 26% for abiotic mineralization in reduced sediments), large 1-D column studies (high sediment/water ratio of aquifers) showed 5.6 times higher NDMA mineralization rates in reduced sediment (half-life 410 ± 147 h) than oxic biomineralization (half life 2293 ± 1866 h). Sequential reduced/oxic biostimulated sediment mineralization (half-life 3180 ± 1094 h) was also inefficient compared to reduced sediment. These promising laboratory-scale results for NDMA mineralization should be investigated at field scale. Future studies of NDMA remediation should focus on the comparison of this in situ abiotic NDMA mineralization (iron-reducing environments) to ex situ biomineralization, which has been shown successful in other studies.

The Role of MAPK Modules and ABA during Abiotic Stress Signaling

KAUST Repository

Zélicourt, Axel de

2016-05-01

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

Generation of RNA in abiotic conditions.

Science.gov (United States)

di Mauro, Ernesto

Generation of RNA in abiotic conditions. Ernesto Di Mauro Dipartimento di Genetica Bi-ologia Molecolare, Universit` "Sapienza" Roma, Italy. a At least four conditions must be satisfied for the spontaneous generation of (pre)-genetic poly-mers: 1) availability of precursors that are activated enough to spontaneously polymerize. Preliminary studies showed that (a) nucleic bases and acyclonucleosides can be synthesized from formamide H2NCOH by simply heating with prebiotically available mineral catalysts [last reviewed in (1)], and that b) nucleic bases can be phosphorylated in every possible posi-tion [2'; 3'; 5'; cyclic 2',3'; cyclic 3',5' (2)]. The higher stability of the cyclic forms allows their accumulation. 2) A polymerization mechanism. A reaction showing the formation of RNA polymers starting from prebiotically plausible precursors (3',5' cyclic GMP and 3', 5'cyclic AMP) was recently reported (3). Polymerization in these conditions is thermodynamically up-hill and an equilibrium is attained that limits the maximum length of the polymer produced to about 40 nucleotides for polyG and 100 nucleotides for polyA. 3) Ligation of the synthesized oligomers. If this type of reaction could occur according to a terminal-joining mechanism and could generate canonical 3',5' phosphodiester bonds, exponential growth would be obtained of the generated oligomers. This type of reaction has been reported (4) , limited to homogeneous polyA sequences and leading to the production of polyA dimers and tetramers. What is still missing are: 4) mechanisms that provide the proof of principle for the generation of sequence complexity. We will show evidence for two mechanisms providing this proof of principle for simple complementary sequences. Namely: abiotic sequence complementary-driven terminal ligation and sequence-complementary terminal growth. In conclusion: all the steps leading to the generation of RNA in abiotic conditions are satisfied. (1) R Saladino, C Crestini, F

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

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Zhi-Juan eFeng

2015-12-01

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

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

COP1 Controls Abiotic Stress Responses by Modulating AtSIZ1 Function Through its E3 Ubiquitin Ligase Activity

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Joo Yong Kim

2016-08-01

Full Text Available Ubiquitination and sumoylation are essential post-translational modifications that regulate growth and development processes in plants, including control of hormone signaling mechanisms and responses to stress. This study showed that COP1 (Constitutive photomorphogenic 1 regulated the activity of Arabidopsis E3 SUMO (Small ubiquitin-related modifier ligase AtSIZ1 through its E3 ubiquitin ligase activity. Yeast two hybrid analysis demonstrated that COP1 and AtSIZ1 directly interacted with one another, and subcellular localization assays indicated that COP1 and AtSIZ1 co-localized in nuclear bodies. Analysis of ubiquitination showed that AtSIZ1 was polyubiquitinated by COP1. The AtSIZ1 level was higher in cop1-4 mutants than in wild-type seedlings under light or dark conditions, and overexpression of a dominant-negative (DN-COP1 mutant led to a substantial increase in AtSIZ1 accumulation. In addition, under drought, cold, and high salt conditions, SUMO-conjugate levels were elevated in DN-COP1-overexpressing plants and cop1-4 mutant plants compared to wild-type plants. Taken together, our results indicate that COP1 controls responses to abiotic stress by modulation of AtSIZ1 levels and activity.

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...

Current perspectives in proteomic analysis of abiotic stress in Grapevines

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Iniga Seraphina George

2014-12-01

Full Text Available Grapes are an important crop plant which forms the basis of a globally important industry. Grape and wine production is particularly vulnerable to environmental and climatic fluctuations, which makes it essential for us to develop a greater understanding of the molecular level responses of grape plants to various abiotic stresses. The completion of the initial grape genome sequence in 2007 has led to a significant increase in research on grapes using proteomics approaches. In this article, we discuss some of the current research on abiotic stress in grapevines, in the context of abiotic stress research in other plant species. We also highlight some of the current limitations in grapevine proteomics and identify areas with promising scope for potential future research.

Dispersal networks for enhancing bacterial degradation in heterogeneous environments

International Nuclear Information System (INIS)

Banitz, Thomas; Wick, Lukas Y.; Fetzer, Ingo; Frank, Karin; Harms, Hauke; Johst, Karin

2011-01-01

Successful biodegradation of organic soil pollutants depends on their bioavailability to catabolically active microorganisms. In particular, environmental heterogeneities often limit bacterial access to pollutants. Experimental and modelling studies revealed that fungal networks can facilitate bacterial dispersal and may thereby improve pollutant bioavailability. Here, we investigate the influence of such bacterial dispersal networks on biodegradation performance under spatially heterogeneous abiotic conditions using a process-based simulation model. To match typical situations in polluted soils, two types of abiotic conditions are studied: heterogeneous bacterial dispersal conditions and heterogeneous initial resource distributions. The model predicts that networks facilitating bacterial dispersal can enhance biodegradation performance for a wide range of these conditions. Additionally, the time horizon over which this performance is assessed and the network's spatial configuration are key factors determining the degree of biodegradation improvement. Our results support the idea of stimulating the establishment of fungal mycelia for enhanced bioremediation of polluted soils. - Highlights: → Bacterial dispersal networks can considerably improve biodegradation performance. → They facilitate bacterial access to dispersal-limited areas and remote resources. → Abiotic conditions, time horizon and network structure govern the improvements. → Stimulating the establishment of fungal mycelia promises enhanced soil remediation. - Simulation modelling demonstrates that fungus-mediated bacterial dispersal can considerably improve the bioavailability of organic pollutants under spatially heterogeneous abiotic conditions typical for water-unsaturated soils.

Dispersal networks for enhancing bacterial degradation in heterogeneous environments

Energy Technology Data Exchange (ETDEWEB)

Banitz, Thomas, E-mail: thomas.banitz@ufz.de [Department of Ecological Modelling, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Wick, Lukas Y.; Fetzer, Ingo [Department of Environmental Microbiology, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Frank, Karin [Department of Ecological Modelling, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Harms, Hauke [Department of Environmental Microbiology, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Johst, Karin [Department of Ecological Modelling, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany)

2011-10-15

Successful biodegradation of organic soil pollutants depends on their bioavailability to catabolically active microorganisms. In particular, environmental heterogeneities often limit bacterial access to pollutants. Experimental and modelling studies revealed that fungal networks can facilitate bacterial dispersal and may thereby improve pollutant bioavailability. Here, we investigate the influence of such bacterial dispersal networks on biodegradation performance under spatially heterogeneous abiotic conditions using a process-based simulation model. To match typical situations in polluted soils, two types of abiotic conditions are studied: heterogeneous bacterial dispersal conditions and heterogeneous initial resource distributions. The model predicts that networks facilitating bacterial dispersal can enhance biodegradation performance for a wide range of these conditions. Additionally, the time horizon over which this performance is assessed and the network's spatial configuration are key factors determining the degree of biodegradation improvement. Our results support the idea of stimulating the establishment of fungal mycelia for enhanced bioremediation of polluted soils. - Highlights: > Bacterial dispersal networks can considerably improve biodegradation performance. > They facilitate bacterial access to dispersal-limited areas and remote resources. > Abiotic conditions, time horizon and network structure govern the improvements. > Stimulating the establishment of fungal mycelia promises enhanced soil remediation. - Simulation modelling demonstrates that fungus-mediated bacterial dispersal can considerably improve the bioavailability of organic pollutants under spatially heterogeneous abiotic conditions typical for water-unsaturated soils.

GmCLC1 Confers Enhanced Salt Tolerance through Regulating Chloride Accumulation in Soybean

Directory of Open Access Journals (Sweden)

Peipei Wei

2016-07-01

Full Text Available The family of chloride channel proteins that mediate Cl- transportation play vital roles in plant nutrient supply, cellular action potential and turgor pressure adjustment, stomatal movement, hormone signal recognition and transduction, Cl- homeostasis, and abiotic and biotic stress tolerance. The anionic toxicity, mainly caused by chloride ions (Cl-, on plants under salt stress remains poorly understood. In this work, we investigated the function of soybean Cl-/H+ antiporter GmCLC1 under salt stress in transgenic Arabidopsis thaliana, soybean, and yeast. We found that GmCLC1 enhanced salt tolerance in transgenic A. thaliana by reducing the Cl- accumulation in shoots and hence released the negative impact of salt stress on plant growth. Overexpression of GmCLC1 in the hairy roots of soybean sequestered more Cl- in their roots and transferred less Cl- to their shoots, leading to lower relative electrolyte leakage values in the roots and leaves. When either the soybean GmCLC1 or the yeast chloride transporter gene, GEF1, was transformed into the yeast gef1 mutant, and then treated with different chloride salts (MnCl2, KCl, NaCl, enhanced survival rate was observed. The result indicates that GmCLC1 and GEF1 exerted similar effects on alleviating the stress of diverse chloride salts on the yeast gef1 mutant. Together, this work suggests a protective function of GmCLC1 under Cl- stress.

Abiotic and biotic drivers of biomass change in a Neotropical forest

NARCIS (Netherlands)

Sande, van der M.T.; Pena Claros, M.; Ascarrunz, Nataly; Arets, E.J.M.M.; Licona, J.C.; Toledo, Marisol; Poorter, L.

2017-01-01

Summary
1. Tropical fores ts play an important role in the global carbon cycle, but the drivers of net forest biomass change (i.e. net carbon sequestration) are poorly understood. Here, we evaluate how abiotic factors (soil co nditions and disturbance) and biotic factors (forest structure,

Can plant-natural enemy communication withstand disruption by biotic and abiotic factors?

Science.gov (United States)

Clavijo McCormick, Andrea

2016-12-01

The attraction of natural enemies towards herbivore-induced plant volatiles is a well-documented phenomenon. However, the majority of published studies are carried under optimal water and nutrient regimes and with just one herbivore. But what happens when additional levels of ecological complexity are added? Does the presence of a second herbivore, microorganisms, and abiotic stress interfere with plant-natural enemy communication? or is communication stable enough to withstand disruption by additional biotic and abiotic factors?Investigating the effects of these additional levels of ecological complexity is key to understanding the stability of tritrophic interactions in natural ecosystems and may aid to forecast the impact of environmental disturbances on these, especially in climate change scenarios, which are often associated with modifications in plant and arthropod species distribution and increased levels of abiotic stress.This review explores the literature on natural enemy attraction to herbivore-induced volatiles when, besides herbivory, plants are challenged by additional biotic and abiotic factors.The aim of this review was to establish the impact of different biotic and abiotic factors on plant-natural enemy communication and to highlight critical aspects to guide future research efforts.

Abiotic and Biotic Formation of Amino Acids in the Enceladus Ocean.

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Steel, Elliot L; Davila, Alfonso; McKay, Christopher P

2017-09-01

The active plume at Enceladus' south pole makes the indirect sampling of its global ocean possible. The partially resolved chemistry of the plume, which points to conditions that are seemingly compatible with life, has made orbital sampling missions a priority. We present a conceptual model of energy flux, hydrothermal H 2 production, and both abiotic and biotic production of amino acids. Based on the energy flux observed at the south pole and the inferred internal hydrothermal activity, we estimate an H 2 production of 0.6-34 mol/s from serpentinization, sufficient to sustain abiotic and biotic amino acid synthesis of 1.6-87 and 1-44 g/s, respectively. Two-dimensional (2D) numerical simulations of the hydrothermal vent suggest that the vent fluids could reach the ice-water boundary in less than 11-55 days for a 50 km deep ocean diluted by ambient ocean water 10 to 1. Concentrations of glycine, alanine, α-amino isobutyric acid, and glutamic acid in the plume and in the ambient ocean could all be above 0.01 μM just due to abiotic production. Biological synthesis, if occurring, could produce a maximum of 90 μM concentrations of amino acids based on a methanogenic ecosystem consuming H 2 and CO 2 . Racemization timescales in the ocean are short compared with production timescales. Thus, no enantiomeric excess is expected in the ambient ocean, and if biology is present, enantiomeric excess at the vent fluids is expected to be less than 10% in the plume. From vent H 2 concentrations of 7.8 mM (e.g., Lost City) and assuming complete H 2 use and conversion to chemical energy by methanogens, cell production is estimated. Annual biomass production in the methanogenic-based biology model is 4 × 10 4 -2 × 10 6 kg/year. This corresponds to cell concentrations ∼10 9 cells/cm 3 in the vents and ∼10 8 cells/cm 3 in the plume, and when diluted into the ambient ocean, we predict cell concentrations of 80-4250 cells/cm 3 . Key Words: Abiotic organic

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

Science.gov (United States)

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

2014-11-01

A novel cold-inducible GSK3/shaggy-like kinase, TaSK5, was isolated from winter wheat using a macroarray-based differential screening approach. TaSK5 showed high similarity to Arabidopsis subgroup I GSK3/shaggy-like kinases ASK-alpha, AtSK-gamma and ASK-epsilon. RNA gel blot analyses revealed TaSK5 induction by cold and NaCl treatments and to a lesser extent by drought treatment. TaSK5 functionally complemented the cold- and salt-sensitive phenotypes of a yeast GSK3/shaggy-like kinase mutant, △mck1. Transgenic Arabidopsis plants overexpressing TaSK5 cDNA showed enhanced tolerance to salt and drought stresses. By contrast, the tolerance of the transgenic plants to freezing stress was not altered. Microarray analysis revealed that a number of abiotic stress-inducible genes were constitutively induced in the transgenic Arabidopsis plants, suggesting that TaSK5 may function in a novel signal transduction pathway that appears to be unrelated to DREB1/CBF regulon and may involve crosstalk between abiotic and hormonal signals. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

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.

Biotic and abiotic variables show little redundancy in explaining tree species distributions

DEFF Research Database (Denmark)

Meier, Elaine S.; Kienast, Felix; Pearman, Peter B.

2010-01-01

Abiotic factors such as climate and soil determine the species fundamental niche, which is further constrained by biotic interactions such as interspecific competition. To parameterize this realized niche, species distribution models (SDMs) most often relate species occurrence data to abiotic var...

Molecular characterization of the sweet potato peroxidase SWPA4 promoter which responds to abiotic stresses and pathogen infection.

Science.gov (United States)

Ryu, Sun-Hwa; Kim, Yun-Hee; Kim, Cha Young; Park, Soo-Young; Kwon, Suk-Yoon; Lee, Haeng-Soon; Kwak, Sang-Soo

2009-04-01

Previously, the swpa4 peroxidase gene has been shown to be inducible by a variety of abiotic stresses and pathogenic infections in sweet potato (Ipomoea batatas). To elucidate its regulatory mechanism at the transcriptional level under various stress conditions, we isolated and characterized the promoter region (2374 bp) of swpa4 (referred to as SWPA4). We performed a transient expression assay in tobacco protoplasts with deletions from the 5'-end of SWPA4 promoter fused to the beta-glucuronidase (GUS) reporter gene. The -1408 and -374 bp deletions relative to the transcription start site (+1) showed 8 and 4.5 times higher GUS expression than the cauliflower mosaic virus 35S promoter, respectively. In addition, transgenic tobacco plants expressing GUS under the control of -2374, -1408 or -374 bp region of SWPA4 promoter were generated and studied in various tissues under abiotic stresses and pathogen infection. Gel mobility shift assays revealed that nuclear proteins from sweet potato cultured cells specifically interacted with 60-bp fragment (-178/-118) in -374 bp promoter region. In silico analysis indicated that four kinds of cis-acting regulatory sequences, reactive oxygen species-related element activator protein 1 (AP1), CCAAT/enhancer-binding protein alpha element, ethylene-responsive element (ERE) and heat-shock element, are present in the -60 bp region (-178/-118), suggesting that the -60 bp region might be associated with stress inducibility of the SWPA4 promoter.

Effect of abiotic stress under light and dark conditions on carotenoid ...

African Journals Online (AJOL)

The aim of this study was to observe the effect of abiotic stress under light and dark conditions on pumpkin calluses carotenoid. Plant elicitors used to create abiotic stress in this study were Polyethylene Glycol 4000 for drought stress, Jasmonic Acid and Salicylic Acid for hormones stress and Murashige and Skoog Salt for ...

Abiotic racemization kinetics of amino acids in marine sediments

DEFF Research Database (Denmark)

Steen, Andrew; Jørgensen, Bo Barker; Lomstein, Bente Aagaard

2013-01-01

Enantiomeric ratios of amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic racemize abiotically. Based on a heating experiment, we report Arrhenius parameters...... between different amino acids or depths. These results can be used in conjunction with measurements of sediment age to predict the ratio of D:L amino acids due solely to abiotic racemization of the source material, deviations from which can indicate the abundance and turnover of active microbial...

Elucidating the Role of Carbon Sources on Abiotic and Biotic Release of Arsenic into Cambodian Aquifers

Science.gov (United States)

Koeneke, M.

2017-12-01

Arsenic (As) is a naturally occurring contaminant in Cambodia that has been contaminating well-water sources of millions of people. Commonly, studies look into the biotic factors that cause the arsenic to be released from aquifer sediments to groundwater. However, abiotic release of As from sediments, though little studied, may also play key roles in As contamination of well water. The goal of this research is to quantitatively compare organic-carbon mediated abiotic and biotic release of arsenic from sediments to groundwater. Batch anaerobic incubation experiments under abiotic (sodium azide used to immobilize microbes) and biotic conditions were conducted using Cambodian aquifer sediments, four different organic carbon sources (sodium lactate, sodium citrate, sodium oxalate, and humic acid), and six different carbon concentrations (0, 1, 2.5, 5, 10, 25mg C/L). Dissolved arsenic, iron(Fe), and manganese(Mn) concentrations in the treatments were measured 112 days . In addition, sediment and solution carbon solution was measured . Collectively, these show how different carbon sources, different carbon concentrations, and how abiotic and biotic factors impact the release of arsenic from Cambodian sediments into aquifers. Overall, an introduction of organic carbon to the soil increases the amount of As released from the sediment. The biotic + abiotic and abiotic conditions seemed to play a minimal role in the amount of As released. Dissolved species analysis showed us that 100% of the As was As(V), Our ICP-MS results vary due to the heterogeneity of samples, but when high levels are Fe are seen in solution, we also see high levels of As. We also see higher As concentrations when there is a smaller amount of Mn in solution.

Towards the Identification of New Genes Involved in ABA-Dependent Abiotic Stresses Using Arabidopsis Suppressor Mutants of abh1 Hypersensitivity to ABA during Seed Germination

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Iwona Szarejko

2013-06-01

Full Text Available Abscisic acid plays a pivotal role in the abiotic stress response in plants. Although great progress has been achieved explaining the complexity of the stress and ABA signaling cascade, there are still many questions to answer. Mutants are a valuable tool in the identification of new genes or new alleles of already known genes and in elucidating their role in signaling pathways. We applied a suppressor mutation approach in order to find new components of ABA and abiotic stress signaling in Arabidopsis. Using the abh1 (ABA hypersensitive 1 insertional mutant as a parental line for EMS mutagenesis, we selected several mutants with suppressed hypersensitivity to ABA during seed germination. Here, we present the response to ABA and a wide range of abiotic stresses during the seed germination and young seedling development of two suppressor mutants—soa2 (suppressor of abh1 hypersensitivity to ABA 2 and soa3 (suppressor of abh1 hypersensitivity to ABA 3. Generally, both mutants displayed a suppression of the hypersensitivity of abh1 to ABA, NaCl and mannitol during germination. Both mutants showed a higher level of tolerance than Columbia-0 (Col-0—the parental line of abh1 in high concentrations of glucose. Additionally, soa2 exhibited better root growth than Col-0 in the presence of high ABA concentrations. soa2 and soa3 were drought tolerant and both had about 50% fewer stomata per mm2 than the wild-type but the same number as their parental line—abh1. Taking into account that suppressor mutants had the same genetic background as their parental line—abh1, it was necessary to backcross abh1 with Landsberg erecta four times for the map-based cloning approach. Mapping populations, derived from the cross of abh1 in the Landsberg erecta background with each suppressor mutant, were created. Map based cloning in order to identify the suppressor genes is in progress.

Microarray meta-analysis to explore abiotic stress-specific gene expression patterns in Arabidopsis.

Science.gov (United States)

Shen, Po-Chih; Hour, Ai-Ling; Liu, Li-Yu Daisy

2017-12-01

Abiotic stresses are the major limiting factors that affect plant growth, development, yield and final quality. Deciphering the underlying mechanisms of plants' adaptations to stresses using few datasets might overlook the different aspects of stress tolerance in plants, which might be simultaneously and consequently operated in the system. Fortunately, the accumulated microarray expression data offer an opportunity to infer abiotic stress-specific gene expression patterns through meta-analysis. In this study, we propose to combine microarray gene expression data under control, cold, drought, heat, and salt conditions and determined modules (gene sets) of genes highly associated with each other according to the observed expression data. By analyzing the expression variations of the Eigen genes from different conditions, we had identified two, three, and five gene modules as cold-, heat-, and salt-specific modules, respectively. Most of the cold- or heat-specific modules were differentially expressed to a particular degree in shoot samples, while most of the salt-specific modules were differentially expressed to a particular degree in root samples. A gene ontology (GO) analysis on the stress-specific modules suggested that the gene modules exclusively enriched stress-related GO terms and that different genes under the same GO terms may be alternatively disturbed in different conditions. The gene regulatory events for two genes, DREB1A and DEAR1, in the cold-specific gene module had also been validated, as evidenced through the literature search. Our protocols study the specificity of the gene modules that were specifically activated under a particular type of abiotic stress. The biplot can also assist to visualize the stress-specific gene modules. In conclusion, our approach has the potential to further elucidate mechanisms in plants and beneficial for future experiments design under different abiotic stresses.

Abscisic Acid and Abiotic Stress Tolerance in Crop Plants

Science.gov (United States)

Sah, Saroj K.; Reddy, Kambham R.; Li, Jiaxu

2016-01-01

Abiotic stress is a primary threat to fulfill the demand of agricultural production to feed the world in coming decades. Plants reduce growth and development process during stress conditions, which ultimately affect the yield. In stress conditions, plants develop various stress mechanism to face the magnitude of stress challenges, although that is not enough to protect them. Therefore, many strategies have been used to produce abiotic stress tolerance crop plants, among them, abscisic acid (ABA) phytohormone engineering could be one of the methods of choice. ABA is an isoprenoid phytohormone, which regulates various physiological processes ranging from stomatal opening to protein storage and provides adaptation to many stresses like drought, salt, and cold stresses. ABA is also called an important messenger that acts as the signaling mediator for regulating the adaptive response of plants to different environmental stress conditions. In this review, we will discuss the role of ABA in response to abiotic stress at the molecular level and ABA signaling. The review also deals with the effect of ABA in respect to gene expression. PMID:27200044

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

Science.gov (United States)

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

2017-01-01

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

CmWRKY1 Enhances the Dehydration Tolerance of Chrysanthemum through the Regulation of ABA-Associated Genes.

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Qingqing Fan

Full Text Available WRKY transcription factors serve as antagonistic or synergistic regulators in a variety of abiotic stress responses in plants. Here, we show that CmWRKY1, a member of the group IIb WRKY family isolated from Chrysanthemum morifolium, exhibits no transcriptional activation in yeast cells. The subcellular localization examination showed that CmWRKY1 localizes to the nucleus in vivo. Furthermore, CmWRKY1-overexpressing transgenic lines exhibit enhanced dehydration tolerance in response to polyethylene glycol (PEG treatment compared with wild-type plants. We further confirmed that the transgenic plants exhibit suppressed expression levels of genes negatively regulated by ABA, such as PP2C, ABI1 and ABI2, and activated expression levels of genes positively regulated by ABA, such as PYL2, SnRK2.2, ABF4, MYB2, RAB18, and DREB1A. Taken together, our results indicate that CmWRKY1 plays an important role in the response to drought in chrysanthemum through an ABA-mediated pathway.

The Role of Silicon under Biotic and Abiotic Stress Conditions

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İlkay YAVAŞ

2017-06-01

Full Text Available Biotic and abiotic stress factors can adversely affect the agricultural productivity leading to physiological and biochemical damage to crops. Therefore, the most effective way is to increase the resistance to stresses. Silicon plays a ro le in reducing the effects of abiotic and biotic stresses (drought, salt stress, disease and insect stress etc. on plants. Silicon is accumulated in the cell walls and intercellular spaces and thus it has beneficial effects on disease infestations in especially small grains. The application of silicon may reduce the effects of environmental stresses on plants while making effective use of plant nutrients such as nitrogen and phosphorous. Also, silicon may reduce the toxic effects of heavy metals in soil. I t may protect the foliage and increase light uptake and reduce respiration. Therefore, in this review, we discussed the effects of silicon on abiotic and biotic stresses in especially field crops.

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.

Elicitation Based Enhancement of Secondary Metabolites in Rauwolfia serpentina and Solanum khasianum Hairy Root Cultures.

Science.gov (United States)

Srivastava, Mrinalini; Sharma, Swati; Misra, Pratibha

2016-05-01

Rauwolfia serpentina and Solanum khasianum are well-known medicinally important plants contained important alkaloids in their different parts. Elicitation of these alkaloids is important because of associated pharmaceutical properties. Targeted metabolites were ajmaline and ajmalicine in R. serpentina; solasodine and α-solanine in S. khasianum. Enhancement of secondary metabolites through biotic and abiotic elicitors in hairy root cultures of R. serpentina and S. khasianum. In this report, hairy root cultures of these two plants were established through Agrobacterium rhizogenes mediated transformation by optimizing various parameters as age of explants, duration of preculture, and co-cultivation period. NaCl was used as abiotic elicitors in these two plants. Cellulase from Aspergillus niger was used as biotic elicitor in S. khasianum and mannan from Saccharomyces cerevisiae was used in R. serpentina. First time we have reported the effect of biotic and abiotic elicitors on the production of important metabolites in hairy root cultures of these two plants. Ajmalicine production was stimulated up to 14.8-fold at 100 mM concentration of NaCl after 1 week of treatment. Ajmaline concentration was also increased 2.9-fold at 100 mg/l dose of mannan after 1 week. Solasodine content was enhanced up to 4.0-fold and 3.6-fold at 100 mM and 200 mM NaCl, respectively, after 6 days of treatments. This study explored the potential of the elicitation strategy in A. rhizogenes transformed cell cultures and this potential further used for commercial production of these pharmaceutically important secondary metabolites. Hairy roots of Rauwolfia serpentina were subjected to salt (abiotic stress) and mannan (biotic stress) treatment for 1 week. Ajmaline and ajmalicine secondary metabolites were quantified before and after stress treatmentAjmalicine yield was enhanced up to 14.8-fold at 100 mM concentration of NaCl. Ajmaline content was also stimulated 2.9-fold at 100 mg/l dose of mannan

WRKY proteins: signaling and regulation of expression during abiotic stress responses.

Science.gov (United States)

Banerjee, Aditya; Roychoudhury, Aryadeep

2015-01-01

WRKY proteins are emerging players in plant signaling and have been thoroughly reported to play important roles in plants under biotic stress like pathogen attack. However, recent advances in this field do reveal the enormous significance of these proteins in eliciting responses induced by abiotic stresses. WRKY proteins act as major transcription factors, either as positive or negative regulators. Specific WRKY factors which help in the expression of a cluster of stress-responsive genes are being targeted and genetically modified to induce improved abiotic stress tolerance in plants. The knowledge regarding the signaling cascade leading to the activation of the WRKY proteins, their interaction with other proteins of the signaling pathway, and the downstream genes activated by them are altogether vital for justified targeting of the WRKY genes. WRKY proteins have also been considered to generate tolerance against multiple abiotic stresses with possible roles in mediating a cross talk between abiotic and biotic stress responses. In this review, we have reckoned the diverse signaling pattern and biological functions of WRKY proteins throughout the plant kingdom along with the growing prospects in this field of research.

Energy harvesting by implantable abiotically catalyzed glucose fuel cells

Science.gov (United States)

Kerzenmacher, S.; Ducrée, J.; Zengerle, R.; von Stetten, F.

Implantable glucose fuel cells are a promising approach to realize an autonomous energy supply for medical implants that solely relies on the electrochemical reaction of oxygen and glucose. Key advantage over conventional batteries is the abundant availability of both reactants in body fluids, rendering the need for regular replacement or external recharging mechanisms obsolete. Implantable glucose fuel cells, based on abiotic catalysts such as noble metals and activated carbon, have already been developed as power supply for cardiac pacemakers in the late-1960s. Whereas, in vitro and preliminary in vivo studies demonstrated their long-term stability, the performance of these fuel cells is limited to the μW-range. Consequently, no further developments have been reported since high-capacity lithium iodine batteries for cardiac pacemakers became available in the mid-1970s. In recent years research has been focused on enzymatically catalyzed glucose fuel cells. They offer higher power densities than their abiotically catalyzed counterparts, but the limited enzyme stability impedes long-term application. In this context, the trend towards increasingly energy-efficient low power MEMS (micro-electro-mechanical systems) implants has revived the interest in abiotic catalysts as a long-term stable alternative. This review covers the state-of-the-art in implantable abiotically catalyzed glucose fuel cells and their development since the 1960s. Different embodiment concepts are presented and the historical achievements of academic and industrial research groups are critically reviewed. Special regard is given to the applicability of the concept as sustainable micro-power generator for implantable devices.

Compartment specific importance of glutathione during abiotic and biotic stress

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Bernd eZechmann

2014-10-01

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

Rubisco Activase Is Also a Multiple Responder to Abiotic Stresses in Rice.

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Yue Chen

Full Text Available Ribulose-1,5-bisphosphate carboxylase/oxygenase activase (RCA is a nuclear gene that encodes a chloroplast protein that plays an important role in photosynthesis. Some reports have indicated that it may play a role in acclimation to different abiotic stresses. In this paper, we analyzed the stress-responsive elements in the 2.0 kb 5'-upstream regions of the RCA gene promoter and the primary, secondary and tertiary structure of the protein. We identified some cis-elements of multiple stress-related components in the RCA promoter. Amino acid and evolution analyses showed that the RCA protein had conserved regions between different species; however, the size and type varied. The secondary structures, binding sites and tertiary structures of the RCA proteins were also different. This might reflect the differences in the transcription and translation levels of the two RCA isoforms during adaptation to different abiotic stresses. Although both the transcription and translation levels of RCA isoforms in the rice leaves increased under various stresses, the large isoform was increased more significantly in the chloroplast stroma and thylakoid. It can be concluded that RCA, especially RCAL, is also a multiple responder to abiotic stresses in rice, which provides new insights into RCA functions.

Plant Enhancers: A Call for Discovery

NARCIS (Netherlands)

Weber, B.; Zicola, J.; Oka, R.; Stam, M.

2016-01-01

Higher eukaryotes typically contain many different cell types, displaying different cellular functions that are influenced by biotic and abiotic cues. The different functions are characterized by specific gene expression patterns mediated by regulatory sequences such as transcriptional enhancers.

Correlation between macrobenthic structure (biotic) and water-sediment characteristics (abiotic) adjacent aquaculture areas at Tembelas Island, indonesia

Science.gov (United States)

Sharani, Jeanny; Hidayat, Jafron W.; Putro, Sapto P.

2018-05-01

Macrobenthic community play important role in sedimentary habitats as a part of food chain. Their structure may be influenced by environmental characteristic spatially and temporally. The purpose of this study is to access the correlation between macrobenthic structure (biotic) and water-sediment characteristics (abiotic) adjacent aquaculture areas at Tembelas Island, Indonesia. Water and sediments samples were taken twice, where the first and second sampling time were taken in June and October 2016, respectively. Samples were taken in the area of fish farming at coastal area of policulture/IMTA (as Location I), site of 1 km away from fish farming area as a reference site (as Location II), and monoculture sites (as Location III), with three stations for each location. Data of abiotic parameters included the composition of sediment substrate and DO, pH, salinity, temperature, and. Sediment samples were taken using Ekman grab. The organisms were 1 mm -size sieved and fixed using 10% formalin for further analysis, i.e. sorting, preserving, enumerating, identifying, and grouping. The relationship between biotics (macrobentos) and abiotics (physical-chemical factors) was assessed using a non-parametric multivariate procedure (BIOENV). This study found 61 species consisting of 46 families and 5 classes of macrobenthos. The most common classes were member of Mollusca and Polychaeta. Total nitrogen, silt, and clay were the abiotic factors most influencing macrobenthic structure (BIO-ENV; r = 0.46; R2 = 21.16%).

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.

Titania may produce abiotic oxygen atmospheres on habitable exoplanets.

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Narita, Norio; Enomoto, Takafumi; Masaoka, Shigeyuki; Kusakabe, Nobuhiko

2015-09-10

The search for habitable exoplanets in the Universe is actively ongoing in the field of astronomy. The biggest future milestone is to determine whether life exists on such habitable exoplanets. In that context, oxygen in the atmosphere has been considered strong evidence for the presence of photosynthetic organisms. In this paper, we show that a previously unconsidered photochemical mechanism by titanium (IV) oxide (titania) can produce abiotic oxygen from liquid water under near ultraviolet (NUV) lights on the surface of exoplanets. Titania works as a photocatalyst to dissociate liquid water in this process. This mechanism offers a different source of a possibility of abiotic oxygen in atmospheres of exoplanets from previously considered photodissociation of water vapor in upper atmospheres by extreme ultraviolet (XUV) light. Our order-of-magnitude estimation shows that possible amounts of oxygen produced by this abiotic mechanism can be comparable with or even more than that in the atmosphere of the current Earth, depending on the amount of active surface area for this mechanism. We conclude that titania may act as a potential source of false signs of life on habitable exoplanets.

Oxygen dependency of neutrophilic Fe(II) oxidation by Leptothrix differs from abiotic reaction

NARCIS (Netherlands)

Vollrath, S.; Behrends, T.; Van Cappellen, P.

2012-01-01

Neutrophilic Fe(II) oxidizing microorganisms are found in many natural environments. It has been hypothesized that, at low oxygen concentrations, microbial iron oxidation is favored over abiotic oxidation. Here, we compare the kinetics of abiotic Fe(II) oxidation to oxidation in the presence of

Cell Wall Metabolism in Response to Abiotic Stress

Science.gov (United States)

Gall, Hyacinthe Le; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine

2015-01-01

This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions. PMID:27135320

An insertional mutagenesis programme with an enhancer trap for the identification and tagging of genes involved in abiotic stress tolerance in the tomato wild-related species Solanum pennellii

OpenAIRE

Atarés Huerta, Alejandro; Moyano, Elena; Morales, Belén; Schleicher, Peter; García Abellán, José Osvaldo; ANTÓN MARTÍNEZ, MARÍA TERESA; García Sogo, Begoña; Pérez Martin, Fernando; Lozano, Rafael; Borja Flores, Francisco; Moreno Ferrero, Vicente; BOLARIN JIMENEZ, MARIA DEL CARMEN; Pineda Chaza, Benito José

2011-01-01

[EN] Salinity and drought have a huge impact on agriculture since there are few areas free of these abiotic stresses and the problem continues to increase. In tomato, the most important horticultural crop worldwide, there are accessions of wild-related species with a high degree of tolerance to salinity and drought. Thus, the finding of insertional mutants with other tolerance levels could lead to the identification and tagging of key genes responsible for abiotic stress tolerance. To this en...

The Wheat Bax Inhibitor-1 Protein Interacts with an Aquaporin TaPIP1 and Enhances Disease Resistance in Arabidopsis

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Pan-Pan Lu

2018-01-01

Full Text Available Bax inhibitor-1 (BI-1 is an endoplasmic reticulum (ER-resident cell death suppressor evolutionarily conserved in eukaryotes. The ability of BI-1 to inhibit the biotic and abiotic stresses have been well-studied in Arabidopsis, while the functions of wheat BI-1 are largely unknown. In this study, the wheat BI-1 gene TaBI-1.1 was isolated by an RNA-seq analysis of Fusarium graminearum (Fg-treated wheat. TaBI-1.1 expression was induced by a salicylic acid (SA treatment and down-regulated by an abscisic acid (ABA treatment. Based on β-glucuronidase (GUS staining, TaBI-1.1 was expressed in mature leaves and roots but not in the hypocotyl or young leaves. Constitutive expression of TaBI-1.1 in Arabidopsis enhanced its resistance to Pseudomonas syringae pv. Tomato (Pst DC3000 infection and induced SA-related gene expression. Additionally, TaBI-1.1 transgenic Arabidopsis exhibited an alleviation of damage caused by high concentrations of SA and decreased the sensitivity to ABA. Consistent with the phenotype, the RNA-seq analysis of 35S::TaBI-1.1 and Col-0 plants showed that TaBI-1.1 was involved in biotic stresses. These results suggested that TaBI-1.1 positively regulates SA signals and plays important roles in the response to biotic stresses. In addition, TaBI-1.1 interacted with the aquaporin TaPIP1, and both them were localized to ER membrane. Furthermore, we demonstrated that TaPIP1 was up-regulated by SA treatment and TaPIP1 transgenic Arabidopsis enhanced the resistance to Pst DC3000 infection. Thus, the interaction between TaBI-1.1 and TaPIP1 on the ER membrane probably occurs in response to SA signals and defense response.

EXPRESSION OF CALCIUM-DEPENDENT PROTEIN KINASE (CDPK GENES IN VITIS AMURENSIS UNDER ABIOTIC STRESS CONDITIONS

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Dubrovina A.S.

2012-08-01

CDPK genes (VaCDPK1a, 1e, 1d, 2a, 3a, 3b, 3c, 3d. We sequenced full cDNA sequences of the genes and analyzed their expression levels by real-time PCR and FAPP method, which has been recently developed by our research group. The prevalent CDPK transcript was VaCDPK3a under both non-stress and abiotic stress conditions. Under high-salt conditions, VaCDPK1d, 1e, 3b, and 3d transcripts were up-regulated. Under high mannitol conditions, expression of VaCPK1e and 3b was up-regulated, while expression of VaCDPK1d, 3c, and 3d was only slightly induced. Under water-deficit, expression of only VaCDPK3b and 3c genes was induced. Cold stress induced expression of VaCDPK2a and 3d genes; while hot stress induced expression of VaCDPK1a, 1d, 1e, 2a, 3a, and 3c genes. Taken together, the data show that the VaCDPK genes are transcriptionally regulated by osmotic, water-deficit, and temperature stresses. The differential expression of the VaCDPK genes during osmotic, water-deficit, and temperature stresses is suggestive of their involvement in the underlying signal transduction pathways.

Changes in biotic and abiotic processes following mangrove clearing

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Granek, Elise; Ruttenberg, Benjamin I.

2008-12-01

Mangrove forests, important tropical coastal habitats, are in decline worldwide primarily due to removal by humans. Changes to mangrove systems can alter ecosystem properties through direct effects on abiotic factors such as temperature, light and nutrient supply or through changes in biotic factors such as primary productivity or species composition. Despite the importance of mangroves as transitional habitats between land and sea, little research has examined changes that occur when they are cleared. We examined changes in a number of biotic and abiotic factors following the anthropogenic removal of red mangroves ( Rhizophora mangle) in the Panamanian Caribbean, including algal biomass, algal diversity, algal grazing rates, light penetration, temperature, sedimentation rates and sediment organic content. In this first study examining multiple ecosystem-level effects of mangrove disturbance, we found that areas cleared of mangroves had higher algal biomass and richness than intact mangrove areas. This increase in algal biomass and richness was likely due to changes in abiotic factors (e.g. light intensity, temperature), but not biotic factors (fish herbivory). Additionally the algal and cyanobacterial genera dominating mangrove-cleared areas were rare in intact mangroves and included a number of genera that compete with coral for space on reefs. Interestingly, sedimentation rates did not differ between intact and cleared areas, but the sediments that accumulated in intact mangroves had higher organic content. These findings are the first to demonstrate that anthropogenic clearing of mangroves changes multiple biotic and abiotic processes in mangrove forests and that some of these changes may influence adjacent habitats such as coral reefs and seagrass beds. Additional research is needed to further explore the community and ecosystem-level effects of mangrove clearing and their influence on adjacent habitats, but it is clear that mangrove conservation is an

Wheat EST resources for functional genomics of abiotic stress

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Links Matthew G

2006-06-01

Full Text Available Abstract Background Wheat is an excellent species to study freezing tolerance and other abiotic stresses. However, the sequence of the wheat genome has not been completely characterized due to its complexity and large size. To circumvent this obstacle and identify genes involved in cold acclimation and associated stresses, a large scale EST sequencing approach was undertaken by the Functional Genomics of Abiotic Stress (FGAS project. Results We generated 73,521 quality-filtered ESTs from eleven cDNA libraries constructed from wheat plants exposed to various abiotic stresses and at different developmental stages. In addition, 196,041 ESTs for which tracefiles were available from the National Science Foundation wheat EST sequencing program and DuPont were also quality-filtered and used in the analysis. Clustering of the combined ESTs with d2_cluster and TGICL yielded a few large clusters containing several thousand ESTs that were refractory to routine clustering techniques. To resolve this problem, the sequence proximity and "bridges" were identified by an e-value distance graph to manually break clusters into smaller groups. Assembly of the resolved ESTs generated a 75,488 unique sequence set (31,580 contigs and 43,908 singletons/singlets. Digital expression analyses indicated that the FGAS dataset is enriched in stress-regulated genes compared to the other public datasets. Over 43% of the unique sequence set was annotated and classified into functional categories according to Gene Ontology. Conclusion We have annotated 29,556 different sequences, an almost 5-fold increase in annotated sequences compared to the available wheat public databases. Digital expression analysis combined with gene annotation helped in the identification of several pathways associated with abiotic stress. The genomic resources and knowledge developed by this project will contribute to a better understanding of the different mechanisms that govern stress tolerance in

Abiotic drivers of Chihuahuan Desert plant communities

Science.gov (United States)

Laura Marie Ladwig

2014-01-01

Within grasslands, precipitation, fire, nitrogen (N) addition, and extreme temperatures influence community composition and ecosystem function. The differential influences of these abiotic factors on Chihuahuan Desert grassland communities was examined within the Sevilleta National Wildlife Refuge, located in central New Mexico, U.S.A. Although fire is a natural...

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

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Shalini Tiwari

2017-08-01

PGPR in rice seedlings subjected to various abiotic stresses and phytohormone treatments for 0, 1, 3, 10, and 24 h.

Origin of Abiotic Methane in Submarine Hydrothermal Systems

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Seewald, J. S.; German, C. R.; Grozeva, N. G.; Klein, F.; McDermott, J. M.; Ono, S.; Reeves, E. P.; Wang, D. T.

2018-05-01

Results of recent investigations into the chemical and isotopic composition of actively venting submarine hydrothermal fluids and volatile species trapped in fluid inclusions will be discussed in the context of processes responsible for abiotic CH4 formation.

Abiotic and microbial interactions during anaerobic transformations of Fe(II and NOx-

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Flynn ePicardal

2012-03-01

Full Text Available Microbial Fe(II oxidation using NO3- as the terminal electron acceptor (nitrate-dependent Fe(II oxidation; NDFO has been studied for over 15 years. Although there are reports of autotrophic isolates and stable enrichments, many of the bacteria capable of NDFO are known organotrophic NO3- -reducers that require the presence of an organic, primary substrate, e.g., acetate, for significant amounts of Fe(II oxidation. Although the thermodynamics of Fe(II oxidation are favorable when coupled to either NO3- or NO2- reduction, the kinetics of abiotic Fe(II oxidation by NO3- are relatively slow except under special conditions. NDFO is typically studied in batch cultures containing millimolar concentrations of Fe(II, NO3-, and the primary substrate. In such systems, NO2- is often observed to accumulate in culture media during Fe(II oxidation. Compared to NO3-, abiotic reactions of biogenic NO2- and Fe(II are relatively rapid. The kinetics and reaction pathways of Fe(II oxidation by NO2- are strongly affected by medium composition and pH, reactant concentration, and the presence of Fe(II-sorptive surfaces, e.g., Fe(III oxyhydroxides and cellular surfaces. In batch cultures, the combination of abiotic and microbial Fe(II oxidation can alter product distribution and, more importantly, results in the formation of intracellular precipitates and extracellular Fe(III oxyhydroxide encrustations that apparently limit further cell growth and Fe(II oxidation. Unless steps are taken to minimize or account for potential abiotic reactions, results of microbial NDFO studies can be obfuscated by artifacts of the chosen experimental conditions, the use of inappropriate analytical methods, and the resulting uncertainties about the relative importance of abiotic and microbial reactions.In this manuscript, abiotic reactions of NO3- and NO2- with aqueous Fe2+, chelated Fe(II, and solid-phase Fe(II are reviewed along with factors that can influence overall NDFO reac

Supplementary Material for: Herboxidiene triggers splicing repression and abiotic stress responses in plants

KAUST Repository

Alshareef, Sahar; Ling, Yu; Butt, Haroon; Mariappan, Kiruthiga; Benhamed, Moussa; Mahfouz, Magdy

2017-01-01

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

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

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Pushpika eUdawat

2016-04-01

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

Overexpression of a Cytosolic Abiotic Stress Responsive Universal Stress Protein (SbUSP) Mitigates Salt and Osmotic Stress in Transgenic Tobacco Plants

Science.gov (United States)

Udawat, Pushpika; Jha, Rajesh K.; Sinha, Dinkar; Mishra, Avinash; Jha, Bhavanath

2016-01-01

The universal stress protein (USP) is a ubiquitous protein and plays an indispensable role in plant abiotic stress tolerance. The genome of Salicornia brachiata contains two homologs of intron less SbUSP gene which encodes for salt and osmotic responsive USP. In vivo localization reveals that SbUSP is a membrane bound cytosolic protein. The role of the gene was functionally validated by developing transgenic tobacco and compared with control [wild-type (WT) and vector control (VC)] plants under different abiotic stress condition. Transgenic lines (T1) exhibited higher chlorophyll, relative water, proline, total sugar, reducing sugar, free amino acids, polyphenol contents, osmotic potential, membrane stability, and lower electrolyte leakage and lipid peroxidation (malondialdehyde content) under stress treatments than control (WT and VC) plants. Lower accumulation of H2O2 and O2− radicals was also detected in transgenic lines compared to control plants under stress conditions. Present study confers that overexpression of the SbUSP gene enhances plant growth, alleviates ROS buildup, maintains ion homeostasis and improves the physiological status of the plant under salt and osmotic stresses. Principal component analysis exhibited a statistical distinction of plant response to salinity stress, and a significant response was observed for transgenic lines under stress, which provides stress endurance to the plant. A possible signaling role is proposed that some downstream genes may get activated by abiotic stress responsive cytosolic SbUSP, which leads to the protection of cell from oxidative damages. The study unveils that ectopic expression of the gene mitigates salt or osmotic stress by scavenging ROS and modulating the physiological process of the plant. PMID:27148338

Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

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Kunoh, Tatsuki; Hashimoto, Hideki; McFarlane, Ian R.; Hayashi, Naoaki; Suzuki, Tomoko; Taketa, Eisuke; Tamura, Katsunori; Takano, Mikio; El-Naggar, Mohamed Y.; Kunoh, Hitoshi; Takada, Jun

2016-01-01

Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II) concentrations, Fe(III) precipitates visibly formed immediately after addition of Fe(II) to the medium, suggesting prompt abiotic oxidation of Fe(II) to Fe(III). Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III) was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II) medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter), while those in the Fe(III) medium were composed of large, aggregated particles (≥3 µm diameter) with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved) of Fe encrustation of the Leptothrix sheaths. PMID:27271677

Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

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Tatsuki Kunoh

2016-06-01

Full Text Available Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II to Fe(III and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II concentrations, Fe(III precipitates visibly formed immediately after addition of Fe(II to the medium, suggesting prompt abiotic oxidation of Fe(II to Fe(III. Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter, while those in the Fe(III medium were composed of large, aggregated particles (≥3 µm diameter with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved of Fe encrustation of the Leptothrix sheaths.

Diagnosis of abiotic and biotic stress factors using the visible symptoms in foliage

International Nuclear Information System (INIS)

Vollenweider, P.; Guenthardt-Goerg, Madeleine S.

2005-01-01

Visible symptoms in the foliage of trees are recorded to monitor the effects of abiotic and biotic stress. Difficulties are reported in diagnosing the origin of stress. The present paper discusses several diagnostic criteria which are usable in different species for a better determination of the stress factor type. A new diagnosis scheme to differentiate between classes of abiotic and biotic stress factors is supplied. Abiotic stress generates gradients of symptoms. The symptom specificity is determined by the degree of interaction between the stress factor and plant defense system. Symptoms caused by abiotic stress and natural autumnal senescence can be morphologically different or undistinguishable according to the stress and plant species. With biotic stress, the class of parasitic is generally recognizable on the basis of the visible symptoms. Structurally and physiologically based explanations of the symptom morphology are still missing for many stress factors. - The morphology and distribution of visible stress symptoms in tree foliage provides diagnostic tools to identify plant defense responses and differentiate stress from natural senescence symptoms

Abiotic factors drives floristic variations of fern's metacommunity in an Atlantic Forest remnant.

Science.gov (United States)

Costa, L E N; Farias, R P; Santiago, A C P; Silva, I A A; Barros, I C L

2018-02-15

We analyzed floristic variations in fern's metacommunity at the local scale and their relationship with abiotic factors in an Atlantic Forest remnant of northeastern Brazil. Floristic and environmental variations were accessed on ten plots of 10 × 20 m. We performed cluster analyses, based on Bray-Curtis dissimilarity index to establish the floristic relationship. The influence of abiotic factors: luminosity, temperature, relative air humidity and relative soil moisture was evaluated from a redundancy analysis. We found 24 species belonging to 20 genera and 12 families. The fern's flora showed high floristic heterogeneity (>75% for most of the plot's associations). The fern's metacommunity was structured along an abiotic gradient modulated by temperature, luminosity, and relative soil moisture.

Effect of abiotic and biotic stress factors analysis using machine learning methods in zebrafish.

Science.gov (United States)

Gutha, Rajasekar; Yarrappagaari, Suresh; Thopireddy, Lavanya; Reddy, Kesireddy Sathyavelu; Saddala, Rajeswara Reddy

2018-03-01

In order to understand the mechanisms underlying stress responses, meta-analysis of transcriptome is made to identify differentially expressed genes (DEGs) and their biological, molecular and cellular mechanisms in response to stressors. The present study is aimed at identifying the effect of abiotic and biotic stress factors, and it is found that several stress responsive genes are common for both abiotic and biotic stress factors in zebrafish. The meta-analysis of micro-array studies revealed that almost 4.7% i.e., 108 common DEGs are differentially regulated between abiotic and biotic stresses. This shows that there is a global coordination and fine-tuning of gene regulation in response to these two types of challenges. We also performed dimension reduction methods, principal component analysis, and partial least squares discriminant analysis which are able to segregate abiotic and biotic stresses into separate entities. The supervised machine learning model, recursive-support vector machine, could classify abiotic and biotic stresses with 100% accuracy using a subset of DEGs. Beside these methods, the random forests decision tree model classified five out of 8 stress conditions with high accuracy. Finally, Functional enrichment analysis revealed the different gene ontology terms, transcription factors and miRNAs factors in the regulation of stress responses. Copyright © 2017 Elsevier Inc. All rights reserved.

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

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Hui Li

2016-01-01

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

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

Science.gov (United States)

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

2016-03-01

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

DISTINGUISHING A HYPOTHETICAL ABIOTIC PLANET–MOON SYSTEM FROM A SINGLE INHABITED PLANET

International Nuclear Information System (INIS)

Li, Tong; Tian, Feng; Wei, Wanjing; Huang, Xiaomeng; Wang, Yuwei

2016-01-01

It has recently been suggested that an exomoon with a CH 4 atmosphere, orbiting an abiotic Earth-mass planet with an O 2 -rich atmosphere, can produce a false positive biosignature at a low–moderate spectral resolution (R = λ/Δλ ≤ 2000). If this were true, inferring the presence of life on exoplanets will be beyond our reach in the next several decades. Here we use a line-by-line radiative transfer model to compute the relevant reflection spectrum between 1 and 3.3 μm. We show that it is possible to separate the combined spectra of such planet–moon systems from an inhabited planet by multiple-band NIR observations. We suggest that future observations near the 2.3 μm CH 4 absorption band at a resolution of 100 and an SNR of 10 or more may be a good way to distinguish an abiotic planet–moon system from a inhabited single planet

A database of annotated tentative orthologs from crop abiotic stress transcripts.

Science.gov (United States)

Balaji, Jayashree; Crouch, Jonathan H; Petite, Prasad V N S; Hoisington, David A

2006-10-07

A minimal requirement to initiate a comparative genomics study on plant responses to abiotic stresses is a dataset of orthologous sequences. The availability of a large amount of sequence information, including those derived from stress cDNA libraries allow for the identification of stress related genes and orthologs associated with the stress response. Orthologous sequences serve as tools to explore genes and their relationships across species. For this purpose, ESTs from stress cDNA libraries across 16 crop species including 6 important cereal crops and 10 dicots were systematically collated and subjected to bioinformatics analysis such as clustering, grouping of tentative orthologous sets, identification of protein motifs/patterns in the predicted protein sequence, and annotation with stress conditions, tissue/library source and putative function. All data are available to the scientific community at http://intranet.icrisat.org/gt1/tog/homepage.htm. We believe that the availability of annotated plant abiotic stress ortholog sets will be a valuable resource for researchers studying the biology of environmental stresses in plant systems, molecular evolution and genomics.

Evaluation of Abiotic Resource LCIA Methods

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Rodrigo A. F. Alvarenga

2016-02-01

Full Text Available In a life cycle assessment (LCA, the impacts on resources are evaluated at the area of protection (AoP with the same name, through life cycle impact assessment (LCIA methods. There are different LCIA methods available in literature that assesses abiotic resources, and the goal of this study was to propose recommendations for that impact category. We evaluated 19 different LCIA methods, through two criteria (scientific robustness and scope, divided into three assessment levels, i.e., resource accounting methods (RAM, midpoint, and endpoint. In order to support the assessment, we applied some LCIA methods to a case study of ethylene production. For RAM, the most suitable LCIA method was CEENE (Cumulative Exergy Extraction from the Natural Environment (but SED (Solar Energy Demand and ICEC (Industrial Cumulative Exergy Consumption/ECEC (Ecological Cumulative Exergy Consumption may also be recommended, while the midpoint level was ADP (Abiotic Depletion Potential, and the endpoint level was both the Recipe Endpoint and EPS2000 (Environmental Priority Strategies. We could notice that the assessment for the AoP Resources is not yet well established in the LCA community, since new LCIA methods (with different approaches and assessment frameworks are showing up, and this trend may continue in the future.

The Role of Tomato WRKY Genes in Plant Responses to Combined Abiotic and Biotic Stresses

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Yuling Bai

2018-06-01

Full Text Available In the field, plants constantly face a plethora of abiotic and biotic stresses that can impart detrimental effects on plants. In response to multiple stresses, plants can rapidly reprogram their transcriptome through a tightly regulated and highly dynamic regulatory network where WRKY transcription factors can act as activators or repressors. WRKY transcription factors have diverse biological functions in plants, but most notably are key players in plant responses to biotic and abiotic stresses. In tomato there are 83 WRKY genes identified. Here we review recent progress on functions of these tomato WRKY genes and their homologs in other plant species, such as Arabidopsis and rice, with a special focus on their involvement in responses to abiotic and biotic stresses. In particular, we highlight WRKY genes that play a role in plant responses to a combination of abiotic and biotic stresses.

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

Cloning of genes and developing transgenic crops with enhanced tolerance to salinity and drought (abstract)

International Nuclear Information System (INIS)

Bansal, K.C.; Chinnusamy, V.; Tayal, D.; Das, A.; Goel, D.; Yadav, V.; Singh, A.K.; Lakhshmi, K.

2005-01-01

Abiotic stresses represent the most limiting factors affecting agricultural productivity. In India more than 60% of total cultivated land is still rainfed and crops experience frequent droughts. Thus, we need to develop transgenic crops tolerant to drought, and other related abiotic stress factors such as salinity, low and high temperature stresses. At the National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute (ICAR), we have initiated a programme on developing transgenic crops tolerant to a range of abiotic stresses. The major emphasis is on developing transgenic potato, tomato, mustard, rice and wheat. While, transgenic plants of potato. tomato and mustard have already been generated with osmotin gene and are at different stages of testing, other key genes imparting tolerance to abiotic stresses are being isolated from different species for producing transgenic rice and wheat cultivars tolerant to multiple stresses. Genes that have been isolated in our laboratory include ascorbate peroxidase gene (TaApx) and genes encoding transcription factor, CBFs (TaCBF2 and TaCBP3) from a drought tolerant wheat cultivar (C306), Lea1 cDNA from Brassica species, codA from Arthrobacter globiformis, and otsBA operon from E. coli. Apart from these stress-related genes, we have isolated a few stress-inducible promoters for deploying them in gene stacking in developing transgenic crops with enhanced tolerance to multiple abiotic stresses. The results will be presented. (author)

Cassava C-repeat binding factor 1 gene responds to low temperature and enhances cold tolerance when overexpressed in Arabidopsis and cassava.

Science.gov (United States)

An, Dong; Ma, Qiuxiang; Wang, Hongxia; Yang, Jun; Zhou, Wenzhi; Zhang, Peng

2017-05-01

Cassava MeCBF1 is a typical CBF transcription factor mediating cold responses but its low expression in apical buds along with a retarded response cause inefficient upregulation of downstream cold-related genes, rendering cassava chilling-sensitive. Low temperature is a major abiotic stress factor affecting survival, productivity and geographic distribution of important crops worldwide. The C-repeat/dehydration-responsive element binding transcription factors (CBF/DREB) are important regulators of abiotic stress response in plants. In this study, MeCBF1, a CBF-like gene, was identified in the tropical root crop cassava (Manihot esculenta Crantz). The MeCBF1 encodes a protein that shares strong homology with DREB1As/CBFs from Arabidopsis as well as other species. The MeCBF1 was localized to the nucleus and is mainly expressed in stem and mature leaves, but not in apical buds or stem cambium. MeCBF1 expression was not only highly responsive to cold, but also significantly induced by salt, PEG and ABA treatment. Several stress-associated cis-elements were found in its promoter region, e.g., ABRE-related, MYC recognition sites, and MYB responsive element. Compared with AtCBF1, the MeCBF1 expression induced by cold in cassava was retarded and upregulated only after 4 h, which was also confirmed by its promoter activity. Overexpression of MeCBF1 in transgenic Arabidopsis and cassava plants conferred enhanced crytolerance. The CBF regulon was smaller and not entirely co-regulated with MeCBF1 expression in overexpressed cassava. The retarded MeCBF1 expression in response to cold and attenuated CBF-regulon might lead cassava to chilling sensitivity.

Glutathione S-Transferases: Role in Combating Abiotic Stresses Including Arsenic Detoxification in Plants

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Smita Kumar

2018-06-01

Full Text Available Arsenic (As, naturally occurring metalloid and a potential hazardous material, is found in low concentrations in the environment and emerges from natural sources and anthropogenic activities. The presence of As in ground water, which is used for irrigation, is a matter of great concern since it affects crop productivity and contaminates food chain. In plants, As alters various metabolic pathways in cells including the interaction of substrates/enzymes with the sulfhydryl groups of proteins and the replacement of phosphate in ATP for energy. In addition, As stimulates the generation of free radicals and reactive oxygen species (ROS, resulting in oxidative stress. Glutathione S-transferases (GSTs quench reactive molecules with the addition of glutathione (GSH and protect the cell from oxidative damage. GSTs are a multigene family of isozymes, known to catalyze the conjugation of GSH to miscellany of electrophilic and hydrophobic substrates. GSTs have been reported to be associated with plant developmental processes and are responsive to multitude of stressors. In past, several studies suggested involvement of plant GST gene family in As response due to the requirement of sulfur and GSH in the detoxification of this toxic metalloid. This review provides updated information about the role of GSTs in abiotic and biotic stresses with an emphasis on As uptake, metabolism, and detoxification in plants. Further, the genetic manipulations that helped in enhancing the understanding of the function of GSTs in abiotic stress response and heavy metal detoxification has been reviewed.

Study of a new alternative antioxidant in soybean plants subjected to abiotic stress

International Nuclear Information System (INIS)

Zilli, C.; Santa Cruz, D.; Caggiano, E.; Romanello, M.; Tomaro, M.; Balestrasse, K.

2010-01-01

We have recently, demonstrated that the induction of heme oxygenase-1 (HO-1) plays a protective role for soybean plants against oxidative stress produced by cadmium and UV-B radiation. At this moment we propose to investigate if the enzyme has the same capacity against another type of abiotic stress, such as drought, for to demonstrate that heme oxygenase acts as an enzyme of plant antioxidant defense system under several different stress situations, as occur in mammalian tissues. To carry out this objective we propose to study, in leaf, root and nodule of soybean plants, the oxidative stress generation; the behavior of classical antioxidant system; the behavior of HO-1 activity and protein and gene expression; the effect of its reaction products and inhibitors on the oxidative stress parameters; the signaling mechanism that produce HO-1 induction and the immunohistochemistry localization of the enzyme in the different plant tissues. The results obtained let us undoubtedly demonstrate the involvement of HO-1 in the antioxidant defense system in plants. This finding will allow the increase in the knowledge of the defense mechanisms in interesting economic plants for our country, such as soybean, and against drought, an abiotic stress considered one of the most important factors limiting plant performance and yield worldwide. (authors)

Arbuscular mycorrhizal fungal responses to abiotic stresses: A review.

Science.gov (United States)

Lenoir, Ingrid; Fontaine, Joël; Lounès-Hadj Sahraoui, Anissa

2016-03-01

The majority of plants live in close collaboration with a diversity of soil organisms among which arbuscular mycorrhizal fungi (AMF) play an essential role. Mycorrhizal symbioses contribute to plant growth and plant protection against various environmental stresses. Whereas the resistance mechanisms induced in mycorrhizal plants after exposure to abiotic stresses, such as drought, salinity and pollution, are well documented, the knowledge about the stress tolerance mechanisms implemented by the AMF themselves is limited. This review provides an overview of the impacts of various abiotic stresses (pollution, salinity, drought, extreme temperatures, CO2, calcareous, acidity) on biodiversity, abundance and development of AMF and examines the morphological, biochemical and molecular mechanisms implemented by AMF to survive in the presence of these stresses. Copyright © 2016 Elsevier Ltd. All rights reserved.

Abiotic production of iodine molecules in irradiated ice

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Choi, Wonyong; Kim, Kitae; Yabushita, Akihiro

2015-04-01

Reactive halogen species play an important role in Earth's environmental systems. Iodine compounds are related to ozone depletion event (ODE) during Antarctic spring, formation of CCN (cloud condensation nuclei), and controlling the atmospheric oxidizing capacity. However, the processes and mechanisms for abiotic formation of iodine compounds in polar region are still unclear. Although the chemical reactions taking place in ice are greatly different from those in aquatic environment, reaction processes of halogens in frozen condition have rarely studied compared to those in water. In this study, we investigated iodide oxidation to form triiodide (I3-) in ice phase under UV irradiation ( λ > 300 nm) and dark condition. The production of I3- through iodide oxidation, which is negligible in aqueous solution, was significantly accelerated in ice phase even in the absence of UV irradiation. The following release of gaseous iodine molecule (I2) to the atmosphere was also monitored by cavity ring-down spectroscopy (CRDS). We speculate that the markedly enhanced iodide oxidation in polycrystalline ice is due to the freeze concentration of iodides, protons, and dissolved oxygen in the ice crystal grain boundaries. The experiments conducted under ambient solar radiation of the Antarctic region (King George Island, 62°13'S 58°47'W, sea level) also confirmed that the generation of I3- via iodide oxidation process is enhanced when iodide is trapped in ice. The observed intrinsic oxidative transformation of iodide to generate I3-(aq) and I2(g) in frozen environment suggests a previously unknown pathway for the substantial release of reactive iodine species to the atmosphere.

Importance of biotic and abiotic components in feedback between plants and soil

OpenAIRE

Hanzelková, Věra

2017-01-01

The plant-soil feedback affects the forming of a plant community. Plants affect their own species as well as other species. The plant-soil feedback can be both positive and negative. Plants affect soil, change its properties, and the soil affects the plants reciprocally. Soil components can be divided into biotic and abiotic ones. The abiotic component is represented by physical and chemical properties of the soil. The main properties are the soil structure, the soil moisture, the soil temper...

Isoelectric point is an inadequate descriptor of MS2, Phi X 174 and PRD1 phages adhesion on abiotic surfaces.

Science.gov (United States)

Dika, Christelle; Duval, Jérôme F L; Francius, Gregory; Perrin, Aline; Gantzer, Christophe

2015-05-15

MS2, Phi X 174 and PRD1 bacteriophages are commonly used as surrogates to evaluate pathogenic virus behavior in natural aquatic media. The interfacial properties of these model soft bioparticles are herein discussed in connection with their propensities to adhere onto abiotic surfaces that differ in terms of surface charges and hydrophobicities. The phages considered in this work exhibit distinct multilayered surface structures and their electrostatic charges are evaluated from the dependence of their electrophoretic mobilities on electrolyte concentration at neutral pH on the basis of electrokinetic theory for soft (bio)particles. The charges of the viruses probed by electrokinetics vary according to the sequence Phi X 174⩽PRD1≪MS2, where 'Phi X 174≪MS2Phi X 174 and PRD1 bacteriophages. Copyright © 2014 Elsevier Inc. All rights reserved.

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

KAUST Repository

Zhang, Xiujuan

2013-06-01

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

Induction of abiotic stress tolerance in plants by endophytic microbes.

Science.gov (United States)

Lata, R; Chowdhury, S; Gond, S K; White, J F

2018-04-01

Endophytes are micro-organisms including bacteria and fungi that survive within healthy plant tissues and promote plant growth under stress. This review focuses on the potential of endophytic microbes that induce abiotic stress tolerance in plants. How endophytes promote plant growth under stressful conditions, like drought and heat, high salinity and poor nutrient availability will be discussed. The molecular mechanisms for increasing stress tolerance in plants by endophytes include induction of plant stress genes as well as biomolecules like reactive oxygen species scavengers. This review may help in the development of biotechnological applications of endophytic microbes in plant growth promotion and crop improvement under abiotic stress conditions. Increasing human populations demand more crop yield for food security while crop production is adversely affected by abiotic stresses like drought, salinity and high temperature. Development of stress tolerance in plants is a strategy to cope with the negative effects of adverse environmental conditions. Endophytes are well recognized for plant growth promotion and production of natural compounds. The property of endophytes to induce stress tolerance in plants can be applied to increase crop yields. With this review, we intend to promote application of endophytes in biotechnology and genetic engineering for the development of stress-tolerant plants. © 2018 The Society for Applied Microbiology.

Cortex proliferation in the root is a protective mechanism against abiotic stress.

Science.gov (United States)

Cui, Hongchang

2015-01-01

Although as an organ the root plays a pivotal role in nutrient and water uptake as well anchorage, individual cell types function distinctly. Cortex is regarded as the least differentiated cell type in the root, but little is known about its role in plant growth and physiology. In recent studies, we found that cortex proliferation can be induced by oxidative stress. Since all types of abiotic stress lead to oxidative stress, this finding suggests a role for cortex in coping with abiotic stress. This hypothesis was tested in this study using the spy mutant, which has an extra layer of cortex in the root. Interestingly, the spy mutant was shown to be hypersensitive to salt and oxidizing reagent applied to the leaves, but it was as tolerant as the wild type to these compounds in the soil. This result lends support to the notion that cortex has a protective role against abiotic stress arising from the soil.

The role of water tracks in altering biotic and abiotic soil properties and processes in a polar desert in Antarctica

Science.gov (United States)

Ball, Becky A.; Levy, Joseph

2015-02-01

Groundwater discharge via water tracks is a largely unexplored passageway routing salts and moisture from high elevations to valley floors in the McMurdo Dry Valleys (MDV) of Antarctica. Given the influence that water tracks have on the distribution of liquid water in seasonally thawed Antarctic soils, it is surprising how little is known about their role in structuring biotic and abiotic processes this cold desert ecosystem. Particularly, it is unclear how soil biota will respond to the activation of new water tracks resulting from enhanced active layer thickening or enhanced regional snowmelt. In the MDV, water tracks are both wetter and more saline than the surrounding soils, constituting a change in soil habitat suitability for soil biology and therefore the ecological processes they carry out. To investigate the net impact that water tracks have on Dry Valley soil biology, and therefore the ecosystem processes for which they are responsible, we analyzed microbial biomass and activity in soils inside and outside of three water tracks and relate this to the physical soil characteristics. Overall, our results suggest that water tracks can significantly influence soil properties, which can further impact biological biovolume and both biotic and abiotic fluxes of CO2. However, the nature of its impact differs with water track, further suggesting that not all water tracks can be regarded the same.

Abiotic Formation of Methyl Halides in the Terrestrial Environment

Science.gov (United States)

Keppler, F.

2011-12-01

Methyl chloride and methyl bromide are the most abundant chlorine and bromine containing organic compounds in the atmosphere. Since both compounds have relatively long tropospheric lifetimes they can effectively transport halogen atoms from the Earth's surface, where they are released, to the stratosphere and following photolytic oxidation form reactive halogen gases that lead to the chemical destruction of ozone. Methyl chloride and methyl bromide account for more than 20% of the ozone-depleting halogens delivered to the stratosphere and are predicted to grow in importance as the chlorine contribution to the stratosphere from anthropogenic CFCs decline. Today methyl chloride and methyl bromide originate mainly from natural sources with only a minor fraction considered to be of anthropogenic origin. However, until as recently as 2000 most of the methyl chloride and methyl bromide input to the atmosphere was considered to originate from the oceans, but investigations in recent years have clearly demonstrated that terrestrial sources such as biomass burning, wood-rotting fungi, coastal salt marshes, tropical vegetation and organic matter degradation must dominate the atmospheric budgets of these trace gases. However, many uncertainties still exist regarding strengths of both sources and sinks, as well as the mechanisms of formation of these naturally occurring halogenated gases. A better understanding of the atmospheric budget of both methyl chloride and methyl bromide is therefore required for reliable prediction of future ozone depletion. Biotic and abiotic methylation processes of chloride and bromide ion are considered to be the dominant pathways of formation of these methyl halides in nature. In this presentation I will focus on abiotic formation processes in the terrestrial environment and the potential parameters that control their emissions. Recent advances in our understanding of the abiotic formation pathway of methyl halides will be discussed. This will

Growth, viability and architecture of biofilms of Listeria monocytogenes formed on abiotic surfaces

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Fernanda Barbosa dos Reis-Teixeira

Full Text Available Abstract The pathogenic bacterium Listeria monocytogenes can persist in food processing plants for many years, even when appropriate hygienic measures are in place, with potential for contaminating ready-to-eat products and, its ability to form biofilms on abiotic surfaces certainly contributes for the environmental persistence. In this research, L. monocytogenes was grown in biofilms up 8 days attached to stainless steel and glass surfaces, contributing for advancing the knowledge on architecture of mature biofilms, since many literature studies carried out on this topic considered only early stages of cell adhesion. In this study, biofilm populations of two strains of L. monocytogenes (serotypes 1/2a and 4b on stainless steel coupons and glass were examined using regular fluorescence microscopy, confocal laser scanning microscopy and classic culture method. The biofilms formed were not very dense and microscopic observations revealed uneven biofilm structures, with presence of exopolymeric matrix surrounding single cells, small aggregates and microcolonies, in a honeycomb-like arrangement. Moreover, planktonic population of L. monocytogenes (present in broth media covering the abiotic surface remained stable throughout the incubation time, which indicates an efficient dispersal mechanism, since the culture medium was replaced daily. In conclusion, even if these strains of L. monocytogenes were not able to form thick multilayer biofilms, it was noticeable their high persistence on abiotic surfaces, reinforcing the need to focus on measures to avoid biofilm formation, instead of trying to eradicate mature biofilms.

Growth, viability and architecture of biofilms of Listeria monocytogenes formed on abiotic surfaces.

Science.gov (United States)

Reis-Teixeira, Fernanda Barbosa Dos; Alves, Virgínia Farias; de Martinis, Elaine Cristina Pereira

The pathogenic bacterium Listeria monocytogenes can persist in food processing plants for many years, even when appropriate hygienic measures are in place, with potential for contaminating ready-to-eat products and, its ability to form biofilms on abiotic surfaces certainly contributes for the environmental persistence. In this research, L. monocytogenes was grown in biofilms up 8 days attached to stainless steel and glass surfaces, contributing for advancing the knowledge on architecture of mature biofilms, since many literature studies carried out on this topic considered only early stages of cell adhesion. In this study, biofilm populations of two strains of L. monocytogenes (serotypes 1/2a and 4b) on stainless steel coupons and glass were examined using regular fluorescence microscopy, confocal laser scanning microscopy and classic culture method. The biofilms formed were not very dense and microscopic observations revealed uneven biofilm structures, with presence of exopolymeric matrix surrounding single cells, small aggregates and microcolonies, in a honeycomb-like arrangement. Moreover, planktonic population of L. monocytogenes (present in broth media covering the abiotic surface) remained stable throughout the incubation time, which indicates an efficient dispersal mechanism, since the culture medium was replaced daily. In conclusion, even if these strains of L. monocytogenes were not able to form thick multilayer biofilms, it was noticeable their high persistence on abiotic surfaces, reinforcing the need to focus on measures to avoid biofilm formation, instead of trying to eradicate mature biofilms. Copyright © 2017. Published by Elsevier Editora Ltda.

Hydroxylated PCBs in abiotic environmental matrices. Precipitation and surface waters

Energy Technology Data Exchange (ETDEWEB)

Darling, C.; Alaee, M.; Campbell, L.; Pacepavicius, G.; Ueno, D.; Muir, D. [National Water Research Institute, Burlington, ON (Canada)

2004-09-15

Hydroxylated PCBs (OH-PCBs) are of great interest environmentally because of their potential thyroidogenic effects. OH-PCBs can compete with thyroxine for binding sites on transthyretin, one of the three main thyroid hormone transport proteins in mammals1. The chemical structures of some OH-PCBs with a para OH group and adjacent chlorine atoms, particularly 4-OH-CB109, 4- OH-CB146, and 4-OH-CB187, share a similar structure to the thyroid hormones (T3 and T4), which have a para OH with adjacent iodine atoms. A number of OH-PCBs have been identified in the blood of humans and biota during the last 5 to 10 years, however, reports on the identity, presence and levels of OH-PCBs are limited. This presentation describes preliminary studies on the presence of OH-PCBs in abiotic samples and comparisons of congener patterns with biological samples. We have previously shown that OHPCBs were present in lake trout from the Great Lakes and nearby large lakes as well as in nearshore environments. We hypothesized that some of the OH-PCB present in fish might be from abiotic formation in water or the atmosphere, or from microbial oxidation of PCBs and/or deconjugation of PCB metabolites in waste treatment plants.

An Alfin-like gene from Atriplex hortensis enhances salt and drought tolerance and abscisic acid response in transgenic Arabidopsis.

Science.gov (United States)

Tao, Jian-Jun; Wei, Wei; Pan, Wen-Jia; Lu, Long; Li, Qing-Tian; Ma, Jin-Biao; Zhang, Wan-Ke; Ma, Biao; Chen, Shou-Yi; Zhang, Jin-Song

2018-02-09

Alfin-like (AL) is a small plant-specific gene family with prominent roles in root growth and abiotic stress response. Here, we aimed to identify novel stress tolerance AL genes from the stress-tolerant species Atriplex hortensis. Totally, we isolated four AhAL genes, all encoding nuclear-localized proteins with cis-element-binding and transrepression activities. Constitutive expression of AhAL1 in Arabidopsis facilitated plants to survive under saline condition, while expressing anyone of the other three AhAL genes led to salt-hypersensitive response, indicating functional divergence of AhAL family. AhAL1 also conferred enhanced drought tolerance, as judged from enhanced survival, improved growth, decreased malonaldehyde (MDA) content and reduced water loss in AhAL1-expressing plants compared to WT. In addition, abscisic acid (ABA)-mediated stomatal closure and inhibition of seed germination and primary root elongation were enhanced in AhAL1-transgenic plants. Further analysis demonstrated that AhAL1 could bind to promoter regions of GRF7, DREB1C and several group-A PP2C genes and repress their expression. Correspondingly, the expression levels of positive stress regulator genes DREB1A, DREB2A and three ABFs were all increased in AhAL1-expressing plants. Based on these results, AhAL1 was identified as a novel candidate gene for improving abiotic stress tolerance of crop plants.

The Stable Isotope Fractionation of Abiotic Reactions: A Benchmark in the Detection of Life

Science.gov (United States)

Summers, David P.

2003-01-01

One very important tool in the analysis of biogenic, and potentially biogenic, samples is the study of their stable isotope distributions. The isotope distribution of a sample depends on the process(es) that created it. One important application of the analysis of C & N stable isotope ratios has been in the determination of whether organic matter in a sample is of biological origin or was produced abiotically. For example, the delta C-13 of organic material found embedded in phosphate grains was cited as a critical part of the evidence for life in 3.8 billion year old samples. The importance of such analysis in establishing biogenicity was highlighted again by the role this issue played in the recent debate over the validity of what had been accepted as the Earth s earliest microfossils. These kinds of analysis imply a comparison with the fractionation that one would have seen if the organic material had been produced by alternative, abiotic, pathways. Could abiotic reactions account for the same level of fractionation? Additionally, since the fractionation can vary between different abiotic reactions, understanding their fractionations can be important in distinguishing what reactions may have been significant in the formation of different abiological samples (such as extraterrestrial samples). There is however, a scarcity of data on the fractionation of carbon and nitrogen by abiotic reactions. In order to interpret properly what the stable isotope ratios of samples tell us about their biotic or abiotic nature, more needs to be known about how abiotic reactions fractionate C and N. Carbon isotope fractionations have been studied for a few abiotic processes. These studies presumed the presence of a reducing atmosphere, focusing on reactions involving spark discharge, W photolysis of reducing gas mixtures, and cyanide polymerization in the presence of ammonia. They did find that the initial products showed a depletion in I3C with values in the range of a few per

Abiotic factors drives floristic variations of fern’s metacommunity in an Atlantic Forest remnant

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L. E. N. Costa

2018-02-01

Full Text Available Abstract We analyzed floristic variations in fern’s metacommunity at the local scale and their relationship with abiotic factors in an Atlantic Forest remnant of northeastern Brazil. Floristic and environmental variations were accessed on ten plots of 10 × 20 m. We performed cluster analyses, based on Bray-Curtis dissimilarity index to establish the floristic relationship. The influence of abiotic factors: luminosity, temperature, relative air humidity and relative soil moisture was evaluated from a redundancy analysis. We found 24 species belonging to 20 genera and 12 families. The fern’s flora showed high floristic heterogeneity (>75% for most of the plot’s associations. The fern’s metacommunity was structured along an abiotic gradient modulated by temperature, luminosity, and relative soil moisture.

Evidence of rock matrix back-diffusion and abiotic dechlorination using a field testing approach

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Schaefer, Charles E.; Lippincott, David R.; Klammler, Harald; Hatfield, Kirk

2018-02-01

An in situ field demonstration was performed in fractured rock impacted with trichloroethene (TCE) and cis-1,2-dichloroethene (DCE) to assess the impacts of contaminant rebound after removing dissolved contaminants within hydraulically conductive fractures. Using a bedrock well pair spaced 2.4 m apart, TCE and DCE were first flushed with water to create a decrease in dissolved contaminant concentrations. While hydraulically isolating the well pair from upgradient contaminant impacts, contaminant rebound then was observed between the well pair over 151 days. The magnitude, but not trend, of TCE rebound was reasonably described by a matrix back-diffusion screening model that employed an effective diffusion coefficient and first-order abiotic TCE dechlorination rate constant that was based on bench-scale testing. Furthermore, a shift in the TCE:DCE ratio and carbon isotopic enrichment was observed during the rebound, suggesting that both biotic and abiotic dechlorination were occurring within the rock matrix. The isotopic data and back-diffusion model together served as a convincing argument that matrix back-diffusion was the mechanism responsible for the observed contaminant rebound. Results of this field demonstration highlight the importance and applicability of rock matrix parameters determined at the bench-scale, and suggest that carbon isotopic enrichment can be used as a line of evidence for abiotic dechlorination within rock matrices.

Abiotic stress and antioxidant enzymes expression in sunflower leaf discs

International Nuclear Information System (INIS)

Yannarelli, G.G.; Azpilicueta, C.E.; Gallego, S.M.; Benavides, M.P.; Tomaro, M.L.

2004-01-01

Full text: Overproduction of reactive oxygen species (ROS) occur in plants under abiotic stress conditions. Although ROS act as mediators of oxidative damage, a signalling role for O 2 - and H 2 O 2 has been proposed. In the present work, the effect of cadmium (300 and 500 μM CdCl 2 ) or UVB radiation (30 KJ/m 2 ) on expression of Cu-Zn superoxide dismutase (sod3) and catalase (cat1 and cat3) was evaluated in sunflower (Helianthus annuus L.) leaf discs. Samples were collected at 0, 4, 8, 12 and 16 h of Cd treatments or white light recuperation after UVB treatment. RNA extractions and semiquantitative RT-PCR analysis were performed. Treatment of 300 μM Cd induced 6.4, 2.9 and 6 fold the expression of sod3, cat1 and cat3 over the controls, respectively, after 8 h of treatment, but 500 μM Cd showed lesser induction levels. Immediately after UVB irradiation, the mRNA of the three enzymes decreased. After 8 h of white light recovery, cat1 and cat3 were induced (1.9 and 3.5 fold, respectively) and the maximum sod3 expression was observed at 12 h (7 fold), respect to control. In conclusion, the balance between superoxide dismutase and peroxidases activities in cells is crucial for determining the steady-state level of O 2 - and H 2 O 2 . In our assay conditions, sod3, cat1 and cat3 were induced in response to abiotic stress at a late phase (8-12 h). The main induction of cat3 suggests that core-catalases of peroxisomes might play a key regulatory role in controlling H 2 O 2 level. (author)

Comparison of the abiotic preferences of macroinvertebrates in tropical river basins.

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Gert Everaert

Full Text Available We assessed and compared abiotic preferences of aquatic macroinvertebrates in three river basins located in Ecuador, Ethiopia and Vietnam. Upon using logistic regression models we analyzed the relationship between the probability of occurrence of five macroinvertebrate families, ranging from pollution tolerant to pollution sensitive, (Chironomidae, Baetidae, Hydroptilidae, Libellulidae and Leptophlebiidae and physical-chemical water quality conditions. Within the investigated physical-chemical ranges, nine out of twenty-five interaction effects were significant. Our analyses suggested river basin dependent associations between the macroinvertebrate families and the corresponding physical-chemical conditions. It was found that pollution tolerant families showed no clear abiotic preference and occurred at most sampling locations, i.e. Chironomidae were present in 91%, 84% and 93% of the samples taken in Ecuador, Ethiopia and Vietnam. Pollution sensitive families were strongly associated with dissolved oxygen and stream velocity, e.g. Leptophlebiidae were only present in 48%, 2% and 18% of the samples in Ecuador, Ethiopia and Vietnam. Despite some limitations in the study design, we concluded that associations between macroinvertebrates and abiotic conditions can be river basin-specific and hence are not automatically transferable across river basins in the tropics.

Atypical Enteropathogenic Escherichia coli Strains form Biofilm on Abiotic Surfaces Regardless of Their Adherence Pattern on Cultured Epithelial Cells

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Hebert F. Culler

2014-01-01

Full Text Available The aim of this study was to determine the capacity of biofilm formation of atypical enteropathogenic Escherichia coli (aEPEC strains on abiotic and biotic surfaces. Ninety-one aEPEC strains, isolated from feces of children with diarrhea, were analyzed by the crystal violet (CV assay on an abiotic surface after 24 h of incubation. aEPEC strains representing each HEp-2 cell type of adherence were analyzed after 24 h and 6, 12, and 18 days of incubation at 37°C on abiotic and cell surfaces by CFU/cm2 counting and confocal laser scanning microscopy (CLSM. Biofilm formation on abiotic surfaces occurred in 55 (60.4% of the aEPEC strains. There was no significant difference in biofilm biomass formation on an abiotic versus prefixed cell surface. The biofilms could be visualized by CLSM at various developmental stages. aEPEC strains are able to form biofilm on an abiotic surface with no association with their adherence pattern on HEp-2 cells with the exception of the strains expressing UND (undetermined adherence. This study revealed the capacity of adhesion and biofilm formation by aEPEC strains on abiotic and biotic surfaces, possibly playing a role in pathogenesis, mainly in cases of persistent diarrhea.

Karrikin-KAI2 signalling provides Arabidopsis seeds with tolerance to abiotic stress and inhibits germination under conditions unfavourable to seedling establishment.

Science.gov (United States)

Wang, Lu; Waters, Mark T; Smith, Steven M

2018-05-04

The control of seed germination in response to environmental conditions is important for plant success. We investigated the role of the karrikin receptor KARRIKIN INSENSITIVE2 (KAI2) in the response of Arabidopsis seeds to osmotic stress, salinity and high temperature. Germination of the kai2 mutant was examined in response to NaCl, mannitol and elevated temperature. The effect of karrikin on germination of wild-type seeds, hypocotyl elongation and the expression of karrikin-responsive genes was also examined in response to such stresses. The kai2 seeds germinated less readily than wild-type seeds and germination was more sensitive to inhibition by abiotic stress. Karrikin-induced KAI2 signalling stimulated germination of wild-type seeds under favourable conditions, but, surprisingly, inhibited germination in the presence of osmolytes or at elevated temperature. By contrast, GA stimulated germination of wild-type seeds and mutants under all conditions. Karrikin induced expression of DLK2 and KUF1 genes and inhibited hypocotyl elongation independently of osmotic stress. Under mild osmotic stress, karrikin enhanced expression of DREB2A, WRKY33 and ERF5 genes, but not ABA signalling genes. Thus, the karrikin-KAI2 signalling system can protect against abiotic stress, first by providing stress tolerance, and second by inhibiting germination under conditions unfavourable to seedling establishment. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Changes in abiotic influences on seed plants and ferns during 18 years of primary succession on Puerto Rican landslides

Science.gov (United States)

Lawrence R. Walker; Aaron B. Shiels; Peter J. Bellingham; Ashley D. Sparrow; Ned Fetcher; Fred H. Landau; Deborah J. Lodge

2013-01-01

Abiotic variables are critical drivers of succession in most primary seres, but how their influence on biota changes over time is rarely examined. Landslides provide good model systems for examining abiotic influences because they are spatially and temporally heterogeneous habitats with distinct abiotic and biotic gradients and post-landslide erosion. In an 18-year...

Major Lipid Body Protein: A Conserved Structural Component of Lipid Body Accumulated during Abiotic Stress in S. quadricauda CASA-CC202

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Arumugam Muthu

2016-11-01

Full Text Available Abiotic stress in oleaginous microalgae enhances lipid accumulation and is stored in a specialised organelle called lipid droplets (LDs. Both the LDs and body are enriched with major lipid droplet protein (MLDP. It serves as a major structural component and also plays a key role in recruiting other proteins and enzymes involved in lipid body maturation. In the present study, the presence of MLDP was detected in two abiotic stress condition namely nitrogen starvation and salt stress condition. Previous research reveals that nitrogen starvation enhances lipid accumulation. Therefore, the effect of salt on growth, biomass yield, and fatty acid profile is studied in detail. The specific growth rate of S. quadricauda under the salt stress of 10mM concentration is about 0.174μ and in control, the SGR is 0.241μ. An increase in the doubling time of the cells shows that the rate of cell division decreases during salt stress (2.87–5.17. The dry biomass content also decreased drastically at 50mM salt-treated cells (129mg/L compared to control (236mg/L on the day 20. The analysis of fatty acid composition also revealed that there is a 20% decrease in the saturated fatty acid level and 19.9% increment in monounsaturated fatty acid level, which makes salt-mediated lipid accumulation as a suitable biodiesel precursor.

Major Lipid Body Protein: A Conserved Structural Component of Lipid Body Accumulated during Abiotic Stress in S. quadricauda CASA-CC202

International Nuclear Information System (INIS)

Javee, Anand; Sulochana, Sujitha Balakrishnan; Pallissery, Steffi James; Arumugam, Muthu

2016-01-01

Abiotic stress in oleaginous microalgae enhances lipid accumulation, which is stored in a specialized organelle called lipid droplets (LDs). Both the LDs or lipid body are enriched with major lipid droplet protein (MLDP). It serves as a major structural component and also plays a key role in recruiting other proteins and enzymes involved in lipid body maturation. In the present study, the presence of MLDP was detected in two abiotic stress condition namely nitrogen starvation and salt stress condition. Previous research reveals that nitrogen starvation enhances lipid accumulation. Therefore, the effect of salt on growth, biomass yield, and fatty acid profile is studied in detail. The specific growth rate of Scenedesmus quadricauda under the salt stress of 10mM concentration is about 0.174 μ and in control, the SGR is 0.241 μ. An increase in the doubling time of the cells shows that the rate of cell division decreases during salt stress (2.87–5.17). The dry biomass content also decreased drastically at 50mM salt-treated cells (129 mg/L) compared to control (236 mg/L) on the day 20. The analysis of fatty acid composition also revealed that there is a 20% decrease in the saturated fatty acid level and 19.9% increment in monounsaturated fatty acid level, which makes salt-mediated lipid accumulation as a suitable biodiesel precursor.

Major Lipid Body Protein: A Conserved Structural Component of Lipid Body Accumulated during Abiotic Stress in S. quadricauda CASA-CC202

Energy Technology Data Exchange (ETDEWEB)

Javee, Anand [Biotechnology Division, National Institute for Interdisciplinary Science and Technology (NIIST), Council of Scientific and Industrial Research (CSIR), Trivandrum (India); Sulochana, Sujitha Balakrishnan [Biotechnology Division, National Institute for Interdisciplinary Science and Technology (NIIST), Council of Scientific and Industrial Research (CSIR), Trivandrum (India); Academy of Scientific and Innovative Research (AcSIR), New Delhi (India); Pallissery, Steffi James [Biotechnology Division, National Institute for Interdisciplinary Science and Technology (NIIST), Council of Scientific and Industrial Research (CSIR), Trivandrum (India); Arumugam, Muthu, E-mail: arumugam@niist.res.in [Biotechnology Division, National Institute for Interdisciplinary Science and Technology (NIIST), Council of Scientific and Industrial Research (CSIR), Trivandrum (India); Academy of Scientific and Innovative Research (AcSIR), New Delhi (India)

2016-11-23

Abiotic stress in oleaginous microalgae enhances lipid accumulation, which is stored in a specialized organelle called lipid droplets (LDs). Both the LDs or lipid body are enriched with major lipid droplet protein (MLDP). It serves as a major structural component and also plays a key role in recruiting other proteins and enzymes involved in lipid body maturation. In the present study, the presence of MLDP was detected in two abiotic stress condition namely nitrogen starvation and salt stress condition. Previous research reveals that nitrogen starvation enhances lipid accumulation. Therefore, the effect of salt on growth, biomass yield, and fatty acid profile is studied in detail. The specific growth rate of Scenedesmus quadricauda under the salt stress of 10mM concentration is about 0.174 μ and in control, the SGR is 0.241 μ. An increase in the doubling time of the cells shows that the rate of cell division decreases during salt stress (2.87–5.17). The dry biomass content also decreased drastically at 50mM salt-treated cells (129 mg/L) compared to control (236 mg/L) on the day 20. The analysis of fatty acid composition also revealed that there is a 20% decrease in the saturated fatty acid level and 19.9% increment in monounsaturated fatty acid level, which makes salt-mediated lipid accumulation as a suitable biodiesel precursor.

When bad guys become good ones: the key role of reactive oxygen species and nitric oxide in the plant responses to abiotic stress

Directory of Open Access Journals (Sweden)

Fernanda Dos Santos Farnese

2016-04-01

Full Text Available The natural environment of plants is composed of a complex set of abiotic stresses and their ability to respond to these stresses is highly flexible and finely balanced through the interaction between signaling molecules. In this review, we highlight the integrated action between reactive oxygen species (ROS and reactive nitrogen species (RNS, particularly nitric oxide (NO, involved in the acclimation to different abiotic stresses. Under stressful conditions, the biosynthesis transport and the metabolism of ROS and NO influence plant response mechanisms. The enzymes involved in ROS and NO synthesis and scavenging can be found in different cells compartments and their temporal and spatial locations are determinant for signaling mechanisms. Both ROS and NO are involved in long distances signaling (ROS wave and GSNO transport, promoting an acquired systemic acclimation to abiotic stresses. The mechanisms of abiotic stresses response triggered by ROS and NO involve some general steps, as the enhancement of antioxidant systems, but also stress-specific mechanisms, according to the stress type (drought, hypoxia, heavy metals, etc, and demand the interaction with other signaling molecules, such as MAPK, plant hormones and calcium. The transduction of ROS and NO bioactivity involves post-translational modifications of proteins, particularly S-glutathionylation for ROS, and S-nitrosylation for NO. These changes may alter the activity, stability, and interaction with other molecules or subcellular location of proteins, changing the entire cell dynamics and contributing to the maintenance of homeostasis. However, despite the recent advances about the roles of ROS and NO in signaling cascades, many challenges remain, and future studies focusing on the signaling of these molecules in planta are still necessary.

When Bad Guys Become Good Ones: The Key Role of Reactive Oxygen Species and Nitric Oxide in the Plant Responses to Abiotic Stress.

Science.gov (United States)

Farnese, Fernanda S; Menezes-Silva, Paulo E; Gusman, Grasielle S; Oliveira, Juraci A

2016-01-01

The natural environment of plants is composed of a complex set of abiotic stresses and their ability to respond to these stresses is highly flexible and finely balanced through the interaction between signaling molecules. In this review, we highlight the integrated action between reactive oxygen species (ROS) and reactive nitrogen species (RNS), particularly nitric oxide (NO), involved in the acclimation to different abiotic stresses. Under stressful conditions, the biosynthesis transport and the metabolism of ROS and NO influence plant response mechanisms. The enzymes involved in ROS and NO synthesis and scavenging can be found in different cells compartments and their temporal and spatial locations are determinant for signaling mechanisms. Both ROS and NO are involved in long distances signaling (ROS wave and GSNO transport), promoting an acquired systemic acclimation to abiotic stresses. The mechanisms of abiotic stresses response triggered by ROS and NO involve some general steps, as the enhancement of antioxidant systems, but also stress-specific mechanisms, according to the stress type (drought, hypoxia, heavy metals, etc.), and demand the interaction with other signaling molecules, such as MAPK, plant hormones, and calcium. The transduction of ROS and NO bioactivity involves post-translational modifications of proteins, particularly S-glutathionylation for ROS, and S-nitrosylation for NO. These changes may alter the activity, stability, and interaction with other molecules or subcellular location of proteins, changing the entire cell dynamics and contributing to the maintenance of homeostasis. However, despite the recent advances about the roles of ROS and NO in signaling cascades, many challenges remain, and future studies focusing on the signaling of these molecules in planta are still necessary.

Pathways for abiotic organic synthesis at submarine hydrothermal fields.

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McDermott, Jill M; Seewald, Jeffrey S; German, Christopher R; Sylva, Sean P

2015-06-23

Arguments for an abiotic origin of low-molecular weight organic compounds in deep-sea hot springs are compelling owing to implications for the sustenance of deep biosphere microbial communities and their potential role in the origin of life. Theory predicts that warm H2-rich fluids, like those emanating from serpentinizing hydrothermal systems, create a favorable thermodynamic drive for the abiotic generation of organic compounds from inorganic precursors. Here, we constrain two distinct reaction pathways for abiotic organic synthesis in the natural environment at the Von Damm hydrothermal field and delineate spatially where inorganic carbon is converted into bioavailable reduced carbon. We reveal that carbon transformation reactions in a single system can progress over hours, days, and up to thousands of years. Previous studies have suggested that CH4 and higher hydrocarbons in ultramafic hydrothermal systems were dependent on H2 generation during active serpentinization. Rather, our results indicate that CH4 found in vent fluids is formed in H2-rich fluid inclusions, and higher n-alkanes may likely be derived from the same source. This finding implies that, in contrast with current paradigms, these compounds may form independently of actively circulating serpentinizing fluids in ultramafic-influenced systems. Conversely, widespread production of formate by ΣCO2 reduction at Von Damm occurs rapidly during shallow subsurface mixing of the same fluids, which may support anaerobic methanogenesis. Our finding of abiogenic formate in deep-sea hot springs has significant implications for microbial life strategies in the present-day deep biosphere as well as early life on Earth and beyond.

Drastic anthocyanin increase in response to PAP1 overexpression in fls1 knockout mutant confers enhanced osmotic stress tolerance in Arabidopsis thaliana.

Science.gov (United States)

Lee, Won Je; Jeong, Chan Young; Kwon, Jaeyoung; Van Kien, Vu; Lee, Dongho; Hong, Suk-Whan; Lee, Hojoung

2016-11-01

KEY MESSAGE : pap1 - D/fls1ko double mutant plants that produce substantial amounts of anthocyanin show tolerance to abiotic stress. Anthocyanins are flavonoids that are abundant in various plants and have beneficial effects on both plants and humans. Many genes in flavonoid biosynthetic pathways have been identified, including those in the MYB-bHLH-WD40 (MBW) complex. The MYB gene Production of Anthocyanin Pigment 1 (PAP1) plays a particularly important role in anthocyanin accumulation. PAP1 expression in many plant systems strongly increases anthocyanin levels, resulting in a dark purple color in many plant organs. In this study, we generated double mutant plants that harbor fls1ko in the pap1-D background (i.e., pap1-D/fls1ko plants), to examine whether anthocyanins can be further enhanced by blocking flavonol biosynthesis under PAP1 overexpression. We also wanted to examine whether the increased anthocyanin levels contribute to defense against osmotic stresses. The pap1-D/fls1ko mutants accumulated higher anthocyanin levels than pap1-D plants in both control and sucrose-treated conditions. However, flavonoid biosynthesis genes were slightly down-regulated in the pap1-D/fls1ko seedlings as compared to their expression in pap1-D seedlings. We also report the performance of pap1-D/fls1ko seedlings in response to plant osmotic stresses.

Salt lakes of Western Australia - Natural abiotic formation of volatile organic compounds

Science.gov (United States)

Krause, T.; Studenroth, S.; Mulder, I.; Tubbesing, C.; Kotte, K.; Ofner, J.; Junkermann, W.; Schöler, H. F.

2012-04-01

Western Australia is a semi-/arid region that is heavily influenced by global climate change and agricultural land use. The area is known for its many ephemeral saline and hypersaline lakes with a wide range of hydrogeochemical parameters that have gradually changed over the last fifty years. Historically, the region was covered by eucalyptus trees and shrubs, but was cleared mainly within 10 years after WWII to make room for wheat and live stock. After the clearance of the deep rooted native plants the groundwater started to rise, bringing increased amounts of dissolved salts and minerals to the surface and discharging them into streams and lakes. Thus most of Western Australia is influenced by secondary salinisation (soil salting) [1]. Another problem is that the discharged minerals affect the pH of ground and surface water, which ranges from acidic to slightly basic. During the 2011 campaign surface water was measured with a pH between 2.5 and 7.1. Another phenomenon in Western Australia is the decrease of rainfall over the last decades assumed to be linked to the secondary salinisation. The rising saline and mineral rich groundwater increases the biotical and abiotical activity of the salt lakes. Halogenated and non-halogenated volatile organic compounds emitted from those lakes undergo fast oxidation and chemical reactions to form small particles modifying cloud microphysics and thus suppressing rain events [2]. Our objective is to gain a better understanding of this extreme environment with its hypersaline acidic lakes with regard to the potential abiotic formation of volatile organic compounds and its impact on the local climate. In spring 2011 fifty-three sediment samples from ten salt lakes in the Lake King region where taken, freeze-dried and ground. In order to simulate the abiotic formation of volatile organic compounds the soil samples were resuspended with water in gas-tight headspace vials. The headspace was measured using a purge and trap GC

Understanding the Interaction of Peptides and Proteins with Abiotic Surfaces: Towards Water-Free Biologics

Science.gov (United States)

2018-02-03

engineering , materials, spectroscopy, laser techniques, chemical biology, computational chemistry, and nanoscience and nanotechnology . We have regular bi...water-free biologics” based on engineered abiotic/biotic interfaces. Using knowledge gained from studies in Aim 1, we aim to a) engineer peptides...universities. The research is highly interdisciplinary, covering many research areas in biology, chemistry, engineering , and physics. The

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-03-20

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

Resilience of cereal crops to abiotic stress: A review

African Journals Online (AJOL)

SAM

2014-07-16

Jul 16, 2014 ... Key words: Cereal crops, abiotic stresses, food insecurity, molecular breeding, quantitative trait loci (QTLs), salinity, water stress. ... production of genetically modified (GM) crops, exo- genous use of osmo protectants etc. ... stressful environments is important to fulfill food demand of the ever-increasing world ...

STRESS ECOLOGY IN FUCUS : ABIOTIC, BIOTIC AND GENETIC INTERACTIONS

NARCIS (Netherlands)

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

2011-01-01

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

Understanding the Posttranscriptional Regulation of Plant Responses to Abiotic Stress

KAUST Repository

Alshareef, Sahar

2017-01-01

Constitutive and alternative splicing of pre-mRNAs from multiexonic genes controls the diversity of the proteome; these precisely regulated processes also fine-tune responses to cues related to growth, development, and biotic and abiotic stresses

Redox Evolution via Gravitational Differentiation on Low-mass Planets: Implications for Abiotic Oxygen, Water Loss, and Habitability

Science.gov (United States)

Wordsworth, R. D.; Schaefer, L. K.; Fischer, R. A.

2018-05-01

The oxidation of rocky planet surfaces and atmospheres, which arises from the twin forces of stellar nucleosynthesis and gravitational differentiation, is a universal process of key importance to habitability and exoplanet biosignature detection. Here we take a generalized approach to this phenomenon. Using a single parameter to describe the redox state, we model the evolution of terrestrial planets around nearby M stars and the Sun. Our model includes atmospheric photochemistry, diffusion and escape, line-by-line climate calculations, and interior thermodynamics and chemistry. In most cases, we find abiotic atmospheric {{{O}}}2 buildup around M stars during the pre-main-sequence phase to be much less than calculated previously, because the planet’s magma ocean absorbs most oxygen liberated from {{{H}}}2{{O}} photolysis. However, loss of noncondensing atmospheric gases after the mantle solidifies remains a significant potential route to abiotic atmospheric {{{O}}}2 subsequently. In all cases, we predict that exoplanets that receive lower stellar fluxes, such as LHS1140b and TRAPPIST-1f and g, have the lowest probability of abiotic {{{O}}}2 buildup and hence may be the most interesting targets for future searches for biogenic {{{O}}}2. Key remaining uncertainties can be minimized in future by comparing our predictions for the atmospheres of hot, sterile exoplanets such as GJ1132b and TRAPPIST-1b and c with observations.

Impact of Post-Translational Modifications of Crop Proteins under Abiotic Stress

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Akiko Hashiguchi

2016-12-01

Full Text Available The efficiency of stress-induced adaptive responses of plants depends on intricate coordination of multiple signal transduction pathways that act coordinately or, in some cases, antagonistically. Protein post-translational modifications (PTMs can regulate protein activity and localization as well as protein–protein interactions in numerous cellular processes, thus leading to elaborate regulation of plant responses to various external stimuli. Understanding responses of crop plants under field conditions is crucial to design novel stress-tolerant cultivars that maintain robust homeostasis even under extreme conditions. In this review, proteomic studies of PTMs in crops are summarized. Although the research on the roles of crop PTMs in regulating stress response mechanisms is still in its early stage, several novel insights have been retrieved so far. This review covers techniques for detection of PTMs in plants, representative PTMs in plants under abiotic stress, and how PTMs control functions of representative proteins. In addition, because PTMs under abiotic stresses are well described in soybeans under submergence, recent findings in PTMs of soybean proteins under flooding stress are introduced. This review provides information on advances in PTM study in relation to plant adaptations to abiotic stresses, underlining the importance of PTM study to ensure adequate agricultural production in the future.

Metabolomics as a Tool to Investigate Abiotic Stress Tolerance in Plants

Directory of Open Access Journals (Sweden)

Aurelio Gómez-Cadenas

2013-03-01

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

The interactive biotic and abiotic processes of DDT transformation under dissimilatory iron-reducing conditions.

Science.gov (United States)

Jin, Xin; Wang, Fang; Gu, Chenggang; Yang, Xinglun; Kengara, Fredrick O; Bian, Yongrong; Song, Yang; Jiang, Xin

2015-11-01

The objective of the study was to elucidate the biotic and abiotic processes under dissimilatory iron reducing conditions involved in reductive dechlorination and iron reduction. DDT transformation was investigated in cultures of Shewanella putrefaciens 200 with/without α-FeOOH. A modified first-order kinetics model was developed and described DDT transformation well. Both the α-FeOOH reduction rate and the dechlorination rate of DDT were positively correlated to the biomass. Addition of α-FeOOH enhanced reductive dechlorination of DDT by favoring the cell survival and generating Fe(II) which was absorbed on the surface of bacteria and iron oxide. 92% of the absorbed Fe(II) was Na-acetate (1M) extractable. However, α-FeOOH also played a negative role of competing for electrons as reflected by the dechlorination rate of DDT was inhibited when increasing the α-FeOOH from 1 g L(-1) to 5 g L(-1). DDT was measured to be toxic to S. putrefaciens 200. The metabolites DDD, DDE and DDMU were recalcitrant to S. putrefaciens 200. The results suggested that iron oxide was not the key factor to promote the dissipation of DDX (DDT and the metabolites), whereas the one-electron reduction potential (E1) of certain organochlorines is the main factor and that the E1 higher than the threshold of the reductive driving forces of DIRB probably ensures the occur of reductive dechlorination. Copyright © 2015 Elsevier Ltd. All rights reserved.

Overexpression of an abiotic-stress inducible plant protein in the ...

African Journals Online (AJOL)

STORAGESEVER

2008-09-17

Sep 17, 2008 ... the universal stress hormone, is supplied in the culture ... various abiotic stress like water deficit, high salinity and low temperature or exogenous ... period in a plant growth chamber (NIPPON, LHP-100-RDS, Tokyo,. Japan).

Abiotic factors drives floristic variations of fern’s metacommunity in an Atlantic Forest remnant

OpenAIRE

L. E. N. Costa; R. P. Farias; A. C. P. Santiago; I. A. A. Silva; I. C. L. Barros

2018-01-01

Abstract We analyzed floristic variations in fern’s metacommunity at the local scale and their relationship with abiotic factors in an Atlantic Forest remnant of northeastern Brazil. Floristic and environmental variations were accessed on ten plots of 10 × 20 m. We performed cluster analyses, based on Bray-Curtis dissimilarity index to establish the floristic relationship. The influence of abiotic factors: luminosity, temperature, relative air humidity and relative soil moisture was evaluated...

Cloning and expression analysis of 14 lipid transfer protein genes from Tamarix hispida responding to different abiotic stresses.

Science.gov (United States)

Wang, Chao; Yang, Chuanping; Gao, Caiqiu; Wang, Yucheng

2009-12-01

Plant lipid transfer proteins (LTPs) are ubiquitous lipid-binding proteins that are involved in various stress responses. In this study, we cloned 14 unique LTP genes (ThLTP 1-14) from Tamarix hispida Willd. (Tamaricaceae) to investigate their roles under various abiotic stress conditions. The expression profiles of the 14 ThLTPs in response to NaCl, polyethylene glycol (PEG), NaHCO(3), CdCl(2) and abscisic acid (ABA) exposure in root, stem and leaf tissues were investigated using real-time RT-PCR. The results showed that all 14 ThLTPs were expressed in root, stem and leaf tissues under normal growth conditions. However, under normal growth conditions, ThLTP abundance varied in each organ, with expression differences of 9000-fold in leaves, 540-fold in stems and 3700-fold in roots. These results indicated that activity and/or physiological importance of these ThLTPs are quite different. Differential expression of the 14 ThLTPs was observed (> 2-fold) for NaCl, PEG, NaHCO(3) and CdCl(2) in at least one tissue indicating that they were all involved in abiotic stress responses. All ThLTP genes were highly induced (> 2-fold) under ABA treatment in roots, stems and/or leaves, and particularly in roots, suggesting that ABA-dependent signaling pathways regulated ThLTPs. We hypothesize that ThLTP expression constitutes an adaptive response to abiotic stresses in T. hispida and plays an important role in abiotic stress tolerance.

[Inhibitors of proteolytic enzymes under abiotic stresses in plants (review)].

Science.gov (United States)

Mosolov, V V; Valueva, T A

2011-01-01

Data on the role of proteolytic enzyme inhibitors in plant adaptation to various unfavorable environmental abiotic factors--water deficiency, salinization of soil, extreme temperatures, etc.--and also probable functions of proteinases inhibitors in natural plant senescense are considered.

Nanodeserts: A Conjecture in Nanotechnology to Enhance Quasi-Photosynthetic CO2 Absorption

Directory of Open Access Journals (Sweden)

Wenfeng Wang

2016-01-01

Full Text Available This paper advances “nanodeserts” as a conjecture on the possibility of developing the hierarchical structured polymeric nanomaterials for enhancing abiotic CO2 fixation in the soil-groundwater system beneath deserts (termed as quasi-photosynthetic CO2 absorption. Arid and semiarid deserts ecosystems approximately characterize one-third of the Earth’s land surface but play an unsung role in the carbon cycling, considering the huge potentials of such CO2 absorption to expand insights to the long-sought missing CO2 sink and the naturally unneglectable turbulence in temperature sensitivities of soil respiration it produced. “Nanodeserts” as a reconciled concept not only indicate a conjecture in nanotechnology to enhance quasi-photosynthetic CO2 absorption, but also aim to present to the desert researchers a better understanding of the footprints of abiotic CO2 transport, conversion, and assignment in the soil-groundwater system beneath deserts. Meanwhile, nanodeserts allow a stable temperature sensitivity of soil respiration in deserts by largely reducing the CO2 release above the deserts surface and highlighting the abiotic CO2 fixation beneath deserts. This may be no longer a novelty in the future.

Abiotic factors influencing tropical dry forests regeneration

Directory of Open Access Journals (Sweden)

Ceccon Eliane

2006-01-01

Full Text Available Tropical dry forests represent nearly half the tropical forests in the world and are the ecosystems registering the greatest deterioration from the anthropogenic exploitation of the land. This paper presents a review on the dynamics of tropical dry forests regeneration and the main abiotic factors influencing this regeneration, such as seasonal nature, soil fertility and humidity, and natural and anthropic disturbances. The main purpose is to clearly understand an important part of TDF succession dynamics.

Characterization and comparison of iron oxyhydroxide precipitates from biotic and abiotic groundwater treatments

DEFF Research Database (Denmark)

Arturi, Katarzyna R.; Bender Koch, Christian; Søgaard, Erik G.

2017-01-01

Removal of iron is an important step in groundwater treatment for drinking water production. It is performed to prevent organoleptic issues and clogging in water supply systems. Iron can be eliminated with a purely physico-chemical (abiotic) method or biotically with the help of iron......-oxidizing bacteria (FeOB). Each of the purification methods requires different operating conditions and results in formation of iron oxyhydroxide (FeOOH) precipitates. Knowledge about the differences in composition and properties of the biotic and abiotic precipitates is desirable from a technical, but also...

MICROSCALE METABOLIC, REDOX AND ABIOTIC REACTIONS IN HANFORD 300 AREA SUBSURFACE SEDIMENTS

Energy Technology Data Exchange (ETDEWEB)

Beyenal, Haluk [WSU; McLEan, Jeff [JCVI; Majors, Paul [PNNL; Fredrickson, Jim [PNNL

2013-11-14

The Hanford 300 Area is a unique site due to periodic hydrologic influence of river water resulting in changes in groundwater elevation and flow direction. This area is also highly subject to uranium remobilization, the source of which is currently believed to be the region at the base of the vadose zone that is subject to period saturation due to the changes in the water levels in the Columbia River. We found that microbial processes and redox and abiotic reactions which operate at the microscale were critical to understanding factors controlling the macroscopic fate and transport of contaminants in the subsurface. The combined laboratory and field research showed how microscale conditions control uranium mobility and how biotic, abiotic and redox reactions relate to each other. Our findings extended the current knowledge to examine U(VI) reduction and immobilization using natural 300 Area communities as well as selected model organisms on redox-sensitive and redox-insensitive minerals. Using innovative techniques developed specifically to probe biogeochemical processes at the microscale, our research expanded our current understanding of the roles played by mineral surfaces, bacterial competition, and local biotic, abiotic and redox reaction rates on the reduction and immobilization of uranium.

Genome-wide analysis of WRKY gene family in the sesame genome and identification of the WRKY genes involved in responses to abiotic stresses.

Science.gov (United States)

Li, Donghua; Liu, Pan; Yu, Jingyin; Wang, Linhai; Dossa, Komivi; Zhang, Yanxin; Zhou, Rong; Wei, Xin; Zhang, Xiurong

2017-09-11

Sesame (Sesamum indicum L.) is one of the world's most important oil crops. However, it is susceptible to abiotic stresses in general, and to waterlogging and drought stresses in particular. The molecular mechanisms of abiotic stress tolerance in sesame have not yet been elucidated. The WRKY domain transcription factors play significant roles in plant growth, development, and responses to stresses. However, little is known about the number, location, structure, molecular phylogenetics, and expression of the WRKY genes in sesame. We performed a comprehensive study of the WRKY gene family in sesame and identified 71 SiWRKYs. In total, 65 of these genes were mapped to 15 linkage groups within the sesame genome. A phylogenetic analysis was performed using a related species (Arabidopsis thaliana) to investigate the evolution of the sesame WRKY genes. Tissue expression profiles of the WRKY genes demonstrated that six SiWRKY genes were highly expressed in all organs, suggesting that these genes may be important for plant growth and organ development in sesame. Analysis of the SiWRKY gene expression patterns revealed that 33 and 26 SiWRKYs respond strongly to waterlogging and drought stresses, respectively. Changes in the expression of 12 SiWRKY genes were observed at different times after the waterlogging and drought treatments had begun, demonstrating that sesame gene expression patterns vary in response to abiotic stresses. In this study, we analyzed the WRKY family of transcription factors encoded by the sesame genome. Insight was gained into the classification, evolution, and function of the SiWRKY genes, revealing their putative roles in a variety of tissues. Responses to abiotic stresses in different sesame cultivars were also investigated. The results of our study provide a better understanding of the structures and functions of sesame WRKY genes and suggest that manipulating these WRKYs could enhance resistance to waterlogging and drought.

An endoplasmic reticulum-localized Coffea arabica BURP domain-containing protein affects the response of transgenic Arabidopsis plants to diverse abiotic stresses.

Science.gov (United States)

Dinh, Sy Nguyen; Kang, Hunseung

2017-11-01

The Coffea arabica BURP domain-containing gene plays an important role in the response of transgenic Arabidopsis plants to abiotic stresses via regulating the level of diverse proteins. Although the functions of plant-specific BURP domain-containing proteins (BDP) have been determined for a few plants, their roles in the growth, development, and stress responses of most plant species, including coffee plant (Coffea arabica), are largely unknown. In this study, the function of a C. arabica BDP, designated CaBDP1, was investigated in transgenic Arabidopsis plants. The expression of CaBDP1 was highly modulated in coffee plants subjected to drought, cold, salt, or ABA. Confocal analysis of CaBDP1-GFP fusion proteins revealed that CaBDP1 is localized in the endoplasmic reticulum. The ectopic expression of CaBDP1 in Arabidopsis resulted in delayed germination of the transgenic plants under abiotic stress and in the presence of ABA. Cotyledon greening and seedling growth of the transgenic plants were inhibited in the presence of ABA due to the upregulation of ABA signaling-related genes like ABI3, ABI4, and ABI5. Proteome analysis revealed that the levels of several proteins are modulated in CaBDP1-expressing transgenic plants. The results of this study underscore the importance of BURP domain proteins in plant responses to diverse abiotic stresses.

Genetic engineering of crops: a ray of hope for enhanced food security.

Science.gov (United States)

Gill, Sarvajeet Singh; Gill, Ritu; Tuteja, Renu; Tuteja, Narendra

2014-01-01

Crop improvement has been a basic and essential chase since organized cultivation of crops began thousands of years ago. Abiotic stresses as a whole are regarded as the crucial factors restricting the plant species to reach their full genetic potential to deliver desired productivity. The changing global climatic conditions are making them worse and pointing toward food insecurity. Agriculture biotechnology or genetic engineering has allowed us to look into and understand the complex nature of abiotic stresses and measures to improve the crop productivity under adverse conditions. Various candidate genes have been identified and transformed in model plants as well as agriculturally important crop plants to develop abiotic stress-tolerant plants for crop improvement. The views presented here are an attempt toward realizing the potential of genetic engineering for improving crops to better tolerate abiotic stresses in the era of climate change, which is now essential for global food security. There is great urgency in speeding up crop improvement programs that can use modern biotechnological tools in addition to current breeding practices for providing enhanced food security.

Overexpression of snapdragon Delila (Del) gene in tobacco enhances anthocyanin accumulation and abiotic stress tolerance

OpenAIRE

Naing, Aung Htay; Park, Kyeung Il; Ai, Trinh Ngoc; Chung, Mi Young; Han, Jeung Sul; Kang, Young-Wha; Lim, Ki Byung; Kim, Chang Kil

2017-01-01

Background Rosea1 (Ros1) and Delila (Del) co-expression controls anthocyanin accumulation in snapdragon flowers, while their overexpression in tomato strongly induces anthocyanin accumulation. However, little data exist on how Del expression alone influences anthocyanin accumulation. Results In tobacco (Nicotiana tabacum ?Xanthi?), Del expression enhanced leaf and flower anthocyanin production through regulating NtCHS, NtCHI, NtF3H, NtDFR, and NtANS transcript levels. Transgenic lines display...

Genetic and Computational Approaches for Studying Plant Development and Abiotic Stress Responses Using Image-Based Phenotyping

Science.gov (United States)

Campbell, M. T.; Walia, H.; Grondin, A.; Knecht, A.

2017-12-01

The development of abiotic stress tolerant crops (i.e. drought, salinity, or heat stress) requires the discovery of DNA sequence variants associated with stress tolerance-related traits. However, many traits underlying adaptation to abiotic stress involve a suite of physiological pathways that may be induced at different times throughout the duration of stress. Conventional single-point phenotyping approaches fail to fully capture these temporal responses, and thus downstream genetic analysis may only identify a subset of the genetic variants that are important for adaptation to sub-optimal environments. Although genomic resources for crops have advanced tremendously, the collection of phenotypic data for morphological and physiological traits is laborious and remains a significant bottleneck in bridging the phenotype-genotype gap. In recent years, the availability of automated, image-based phenotyping platforms has provided researchers with an opportunity to collect morphological and physiological traits non-destructively in a highly controlled environment. Moreover, these platforms allow abiotic stress responses to be recorded throughout the duration of the experiment, and have facilitated the use of function-valued traits for genetic analyses in major crops. We will present our approaches for addressing abiotic stress tolerance in cereals. This talk will focus on novel open-source software to process and extract biological meaningful data from images generated from these phenomics platforms. In addition, we will discuss the statistical approaches to model longitudinal phenotypes and dissect the genetic basis of dynamic responses to these abiotic stresses throughout development.

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

Science.gov (United States)

Harfouche, Antoine; Meilan, Richard; Altman, Arie

2014-11-01

Abiotic stresses, such as drought, salinity and cold, are the major environmental stresses that adversely affect tree growth and, thus, forest productivity, and play a major role in determining the geographic distribution of tree species. Tree responses and tolerance to abiotic stress are complex biological processes that are best analyzed at a systems level using genetic, genomic, metabolomic and phenomic approaches. This will expedite the dissection of stress-sensing and signaling networks to further support efficient genetic improvement programs. Enormous genetic diversity for stress tolerance exists within some forest-tree species, and due to advances in sequencing technologies the molecular genetic basis for this diversity has been rapidly unfolding in recent years. In addition, the use of emerging phenotyping technologies extends the suite of traits that can be measured and will provide us with a better understanding of stress tolerance. The elucidation of abiotic stress-tolerance mechanisms will allow for effective pyramiding of multiple tolerances in a single tree through genetic engineering. Here we review recent progress in the dissection of the molecular basis of abiotic stress tolerance in forest trees, with special emphasis on Populus, Pinus, Picea, Eucalyptus and Quercus spp. We also outline practices that will enable the deployment of trees engineered for abiotic stress tolerance to land owners. Finally, recommendations for future work are discussed. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Abiotic stressors and stress responses

DEFF Research Database (Denmark)

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

2015-01-01

Abstract Organisms are regularly subjected to abiotic stressors related to increasing anthropogenic activities, including chemicals and climatic changes that induce major stresses. Based on various key taxa involved in ecosystem functioning (photosynthetic microorganisms, plants, invertebrates), we...... review how organisms respond and adapt to chemical- and temperature-induced stresses from molecular to population level. Using field-realistic studies, our integrative analysis aims to compare i) how molecular and physiological mechanisms related to protection, repair and energy allocation can impact...... life history traits of stressed organisms, and ii) to what extent trait responses influence individual and population responses. Common response mechanisms are evident at molecular and cellular scales but become rather difficult to define at higher levels due to evolutionary distance and environmental...

ROS-mediated abiotic stress-induced programmed cell death in plants

NARCIS (Netherlands)

Petrov, Veselin; Hille, Jacob; Mueller-Rober, Bernd; Gechev, Tsanko S.

2015-01-01

During the course of their ontogenesis plants are continuously exposed to a large variety of abiotic stress factors which can damage tissues and jeopardize the survival of the organism unless properly countered. While animals can simply escape and thus evade stressors, plants as sessile organisms

Roles of Arbuscular Mycorrhizal Fungi and Soil Abiotic Conditions in the Establishment of a Dry Grassland Community

Czech Academy of Sciences Publication Activity Database

Knappová, Jana; Pánková, Hana; Münzbergová, Zuzana

2016-01-01

Roč. 11, č. 7 (2016), s. 1-24 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA15-11635S Institutional support: RVO:67985939 Keywords : AMF * dry grassland commnunity * soil abiotic conditions Subject RIV: EF - Botanics Impact factor: 2.806, year: 2016

Constitutive Expression of a miR319 Gene Alters Plant Development and Enhances Salt and Drought Tolerance in Transgenic Creeping Bentgrass1[W][OA

Science.gov (United States)

Zhou, Man; Li, Dayong; Li, Zhigang; Hu, Qian; Yang, Chunhua; Zhu, Lihuang; Luo, Hong

2013-01-01

MicroRNA319 (miR319) is one of the first characterized and conserved microRNA families in plants and has been demonstrated to target TCP (for TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTORS [PCF]) genes encoding plant-specific transcription factors. MiR319 expression is regulated by environmental stimuli, suggesting its involvement in plant stress response, although experimental evidence is lacking and the underlying mechanism remains elusive. This study investigates the role that miR319 plays in the plant response to abiotic stress using transgenic creeping bentgrass (Agrostis stolonifera) overexpressing a rice (Oryza sativa) miR319 gene, Osa-miR319a. We found that transgenic plants overexpressing Osa-miR319a displayed morphological changes and exhibited enhanced drought and salt tolerance associated with increased leaf wax content and water retention but reduced sodium uptake. Gene expression analysis indicated that at least four putative miR319 target genes, AsPCF5, AsPCF6, AsPCF8, and AsTCP14, and a homolog of the rice NAC domain gene AsNAC60 were down-regulated in transgenic plants. Our results demonstrate that miR319 controls plant responses to drought and salinity stress. The enhanced abiotic stress tolerance in transgenic plants is related to significant down-regulation of miR319 target genes, implying their potential for use in the development of novel molecular strategies to genetically engineer crop species for enhanced resistance to environmental stress. PMID:23292790

Spatially dependent biotic and abiotic factors drive survivorship and physical structure of green roof vegetation.

Science.gov (United States)

Aloisio, Jason M; Palmer, Matthew I; Giampieri, Mario A; Tuininga, Amy R; Lewis, James D

2017-01-01

Plant survivorship depends on biotic and abiotic factors that vary at local and regional scales. This survivorship, in turn, has cascading effects on community composition and the physical structure of vegetation. Survivorship of native plant species is variable among populations planted in environmentally stressful habitats like urban roofs, but the degree to which factors at different spatial scales affect survivorship in urban systems is not well understood. We evaluated the effects of biotic and abiotic factors on survivorship, composition, and physical structure of two native perennial species assemblages, one characterized by a mixture of C 4 grasses and forbs (Hempstead Plains, HP) and one characterized by a mixture of C 3 grasses and forbs (Rocky Summit, RS), that were initially sown at equal ratios of growth forms (5:1:4; grass, N-fixing forb and non-N-fixing forb) in replicate 2-m 2 plots planted on 10 roofs in New York City (New York, USA). Of 24 000 installed plants, 40% survived 23 months after planting. Within-roof factors explained 71% of variation in survivorship, with biotic (species identity and assemblage) factors accounting for 54% of the overall variation, and abiotic (growing medium depth and plot location) factors explaining 17% of the variation. Among-roof factors explained 29% of variation in survivorship and increased solar radiation correlated with decreased survivorship. While growing medium properties (pH, nutrients, metals) differed among roofs there was no correlation with survivorship. Percent cover and sward height increased with increasing survivorship. At low survivorship, cover of the HP assemblage was greater compared to the RS assemblage. Sward height of the HP assemblage was about two times greater compared to the RS assemblage. These results highlight the effects of local biotic and regional abiotic drivers on community composition and physical structure of green roof vegetation. As a result, initial green roof plant

Effect of plant growth hormones and abiotic stresses on germination ...

African Journals Online (AJOL)

Phosphatases are widely found in plants having intracellular and extracellular activities. Phosphatases are believed to be important for phosphorous scavenging and remobilization in plants, but its role in adaptation to abiotic stresses and growth hormones at germination level has not been critically evaluated. To address ...

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.

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

Directory of Open Access Journals (Sweden)

Su Zhen

2011-07-01

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

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

Science.gov (United States)

2011-01-01

Background Salt stress hinders the growth of plants and reduces crop production worldwide. However, different plant species might possess different adaptive mechanisms to mitigate salt stress. We conducted a detailed pathway analysis of transcriptional dynamics in the roots of Medicago truncatula seedlings under salt stress and selected a transcription factor gene, MtCBF4, for experimental validation. Results A microarray experiment was conducted using root samples collected 6, 24, and 48 h after application of 180 mM NaCl. Analysis of 11 statistically significant expression profiles revealed different behaviors between primary and secondary metabolism pathways in response to external stress. Secondary metabolism that helps to maintain osmotic balance was induced. One of the highly induced transcription factor genes was successfully cloned, and was named MtCBF4. Phylogenetic analysis revealed that MtCBF4, which belongs to the AP2-EREBP transcription factor family, is a novel member of the CBF transcription factor in M. truncatula. MtCBF4 is shown to be a nuclear-localized protein. Expression of MtCBF4 in M. truncatula was induced by most of the abiotic stresses, including salt, drought, cold, and abscisic acid, suggesting crosstalk between these abiotic stresses. Transgenic Arabidopsis over-expressing MtCBF4 enhanced tolerance to drought and salt stress, and activated expression of downstream genes that contain DRE elements. Over-expression of MtCBF4 in M. truncatula also enhanced salt tolerance and induced expression level of corresponding downstream genes. Conclusion Comprehensive transcriptomic analysis revealed complex mechanisms exist in plants in response to salt stress. The novel transcription factor gene MtCBF4 identified here played an important role in response to abiotic stresses, indicating that it might be a good candidate gene for genetic improvement to produce stress-tolerant plants. PMID:21718548

Species associations overwhelm abiotic conditions to dictate the structure and function of wood-decay fungal communities.

Science.gov (United States)

Maynard, Daniel S; Covey, Kristofer R; Crowther, Thomas W; Sokol, Noah W; Morrison, Eric W; Frey, Serita D; van Diepen, Linda T A; Bradford, Mark A

2018-04-01

Environmental conditions exert strong controls on the activity of saprotrophic microbes, yet abiotic factors often fail to adequately predict wood decomposition rates across broad spatial scales. Given that species interactions can have significant positive and negative effects on wood-decay fungal activity, one possibility is that biotic processes serve as the primary controls on community function, with abiotic controls emerging only after species associations are accounted for. Here we explore this hypothesis in a factorial field warming- and nitrogen-addition experiment by examining relationships among wood decomposition rates, fungal activity, and fungal community structure. We show that functional outcomes and community structure are largely unrelated to abiotic conditions, with microsite and plot-level abiotic variables explaining at most 19% of the total variability in decomposition and fungal activity, and 2% of the variability in richness and evenness. In contrast, taxonomic richness, evenness, and species associations (i.e., co-occurrence patterns) exhibited strong relationships with community function, accounting for 52% of the variation in decomposition rates and 73% in fungal activity. A greater proportion of positive vs. negative species associations in a community was linked to strong declines in decomposition rates and richness. Evenness emerged as a key mediator between richness and function, with highly even communities exhibiting a positive richness-function relationship and uneven communities exhibiting a negative or null response. These results suggest that community-assembly processes and species interactions are important controls on the function of wood-decay fungal communities, ultimately overwhelming substantial differences in abiotic conditions. © 2018 by the Ecological Society of America.

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

Science.gov (United States)

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

2015-05-25

Abiotic stresses usually cause H2O2 accumulation, with harmful effects, in plants. Catalase may play a key protective role in plant cells by detoxifying this excess H2O2. Pitaya (Hylocereus undatus) shows broad ecological adaptation due to its high tolerance to abiotic stresses, e.g. drought, heat and poor soil. However, involvement of the pitaya catalase gene (HuCAT) in tolerance to abiotic stresses is unknown. In the present study, a full-length HuCAT3 cDNA (1870 bp) was isolated from pitaya based on our previous microarray data and RACE method. The cDNA sequence and deduced amino acid sequence shared 73-77% and 75-80% identity with other plant catalases, respectively. HuCAT3 contains conserved catalase family domain and catalytic sites. Pairwise comparison and phylogenetic analysis indicated that HuCAT3 is most similar to Eriobotrya japonica CAT, followed by Dimocarpus longan CAT and Nicotiana tabacum CAT1. Expression profile analysis demonstrated that HuCAT3 is mainly expressed in green cotyledons and mature stems, and was regulated by H2O2, drought, cold and salt stress, whereas, its expression patterns and maximum expression levels varied with stress types. HuCAT activity increased as exposure to the tested stresses, and the fluctuation of HuCAT activity was consistent with HuCAT3 mRNA abundance (except for 0.5 days upon drought stress). HuCAT3 mRNA elevations and HuCAT activities changes under cold stress were also in conformity with the cold tolerances among the four genotypes. The obtained results confirmed a major role of HuCAT3 in abiotic stress response of pitaya. This may prove useful in understanding pitaya's high tolerance to abiotic stresses at molecular level. Copyright © 2015 Elsevier B.V. All rights reserved.

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

Directory of Open Access Journals (Sweden)

Henry D Priest

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

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.

Identification and Expression Profiling of the Auxin Response Factors in Dendrobium officinale under Abiotic Stresses.

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Chen, Zhehao; Yuan, Ye; Fu, Di; Shen, Chenjia; Yang, Yanjun

2017-05-04

Auxin response factor (ARF) proteins play roles in plant responses to diverse environmental stresses by binding specifically to the auxin response element in the promoters of target genes. Using our latest public Dendrobium transcriptomes, a comprehensive characterization and analysis of 14 DnARF genes were performed. Three selected DnARFs , including DnARF1 , DnARF4 , and DnARF6 , were confirmed to be nuclear proteins according to their transient expression in epidermal cells of Nicotiana benthamiana leaves. Furthermore, the transcription activation abilities of DnARF1 , DnARF4 , and DnARF6 were tested in a yeast system. Our data showed that DnARF6 is a transcriptional activator in Dendrobium officinale . To uncover the basic information of DnARF gene responses to abiotic stresses, we analyzed their expression patterns under various hormones and abiotic treatments. Based on our data, several hormones and significant stress responsive DnARF genes have been identified. Since auxin and ARF genes have been identified in many plant species, our data is imperative to reveal the function of ARF mediated auxin signaling in the adaptation to the challenging Dendrobium environment.

A significant abiotic pathway for the formation of unknown nitrogen in nature

Science.gov (United States)

Jokic, A.; Schulten, H.-R.; Cutler, J. N.; Schnitzer, M.; Huang, P. M.

2004-03-01

The global nitrogen cycle is of prime importance in natural ecosystems. However, the origin and nature of up to one-half of total soil N remains obscure despite all attempts at elucidation. Our data provide, for the first time, unequivocal evidence that the promoting action of Mn (IV) oxide on the Maillard reaction (sugar-amino acid condensation) under ambient conditions results in the abiotic formation of heterocyclic N compounds, which are often referred to as unknown nitrogen, and of amides which are apparently the dominant N moieties in nature. The information presented is of fundamental significance in understanding the role of mineral colloids in abiotic transformations of organic N moieties, the incorporation of N in the organic matrix of fossil fuels, and the global N cycle.

Review of Abiotic Degradation of Chlorinated Solvents by Reactive Iron Minerals

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Abiotic degradation of chlorinated solvents by reactive iron minerals such as iron sulfides, magnetite, green rust, and other Fe(II)-containing minerals has been observed in both laboratory and field conditions. These reactive iron minerals typically form under iron and sulfate ...

Responses of transgenic Arabidopsis plants and recombinant yeast cells expressing a novel durum wheat manganese superoxide dismutase TdMnSOD to various abiotic stresses.

Science.gov (United States)

Kaouthar, Feki; Ameny, Farhat-Khemakhem; Yosra, Kamoun; Walid, Saibi; Ali, Gargouri; Faiçal, Brini

2016-07-01

In plant cells, the manganese superoxide dismutase (Mn-SOD) plays an elusive role in the response to oxidative stress. In this study, we describe the isolation and functional characterization of a novel Mn-SOD from durum wheat (Triticum turgidum L. subsp. Durum), named TdMnSOD. Molecular phylogeny analysis showed that the durum TdMnSOD exhibited high amino acids sequence identity with other Mn-SOD plants. The three-dimensional structure showed that TdMnSOD forms a homotetramer and each subunit is composed of a predominantly α-helical N-terminal domain and a mixed α/β C-terminal domain. TdMnSOD gene expression analysis showed that this gene was induced by various abiotic stresses in durum wheat. The expression of TdMnSOD enhances tolerance of the transformed yeast cells to salt, osmotic, cold and H2O2-induced oxidative stresses. Moreover, the analysis of TdMnSOD transgenic Arabidopsis plants subjected to different environmental stresses revealed low H2O2 and high proline levels as compared to the wild-type plants. Compared with the non-transformed plants, an increase in the total SOD and two other antioxidant enzyme activities including catalase (CAT) and peroxidases (POD) was observed in the three transgenic lines subjected to abiotic stress. Taken together, these data provide evidence for the involvement of durum wheat TdMnSOD in tolerance to multiple abiotic stresses in crop plants. Copyright © 2016 Elsevier GmbH. All rights reserved.

Chemiluminescent Diagnostics of Free-Radical Processes in an Abiotic System and in Liver Cells in the Presence of Nanoparticles Based on Rare-Earth Elements nReVO4:Eu3+ (Re = Gd, Y, La) and CeO2

Science.gov (United States)

Averchenko, E. A.; Kavok, N. S.; Klochkov, V. K.; Malyukin, Yu. V.

2014-11-01

We have used luminol-dependent chemiluminescence with Fenton's reagent to study the effect of nanoparticles based on rare-earth elements of different sizes and shapes on free-radical processes in abiotic and biotic cell-free systems, and also in isolated cells in vitro. We have estimated the effects of rare-earth orthovanadate nanoparticles of spherical (GdYVO4:Eu3+, 1-2 nm), spindle-shaped (GdVO4:Eu3+, 25 ×8 nm), and rod-shaped (LaVO4:Eu3+, 57 × (6-8) nm) nanoparticles and spherical CeO2 nanoparticles (sizes 1-2 nm and 8-10 nm). We have shown that in contrast to the abiotic system, in which all types of nanoparticles exhibit antiradical activity, in the presence of biological material, extra-small spherical (1-2 nm) nanoparticles of both types exhibit pro-oxidant activity, and also enhance pro-oxidant induced oxidative stress (for the pro-oxidants hydrogen peroxide and tert-butyl hydroperoxide). The effect of rare-earth orthovanadate spindle and rod shaped nanoparticles in this system was neutral; a moderate antioxidant effect was exhibited by 8-10 nm CeO2 nanoparticles.

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

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DiCaprio, Erin; Purgianto, Anastasia; Li, Jianrong

2015-07-01

Human norovirus (NoV) is the major causative agent of fresh-produce-related outbreaks of gastroenteritis; however, the ecology and persistence of human NoV in produce systems are poorly understood. In this study, the effects of abiotic and biotic stresses on the internalization and dissemination of two human NoV surrogates (murine norovirus 1 [MNV-1] and Tulane virus [TV]) in romaine lettuce were determined. To induce abiotic stress, romaine lettuce was grown under drought and flood conditions that mimic extreme weather events, followed by inoculation of soil with MNV-1 or TV. Independently, lettuce plants were infected with lettuce mosaic virus (LMV) to induce biotic stress, followed by inoculation with TV. Plants were grown for 14 days, and viral titers in harvested tissues were determined by plaque assays. It was found that drought stress significantly decreased the rates of both MNV-1 and TV internalization and dissemination. In contrast, neither flood stress nor biotic stress significantly impacted viral internalization or dissemination. Additionally, the rates of TV internalization and dissemination in soil-grown lettuce were significantly higher than those for MNV-1. Collectively, these results demonstrated that (i) human NoV surrogates can be internalized via roots and disseminated to shoots and leaves of romaine lettuce grown in soil, (ii) abiotic stress (drought) but not biotic stress (LMV infection) affects the rates of viral internalization and dissemination, and (iii) the type of virus affects the efficiency of internalization and dissemination. This study also highlights the need to develop effective measures to eliminate internalized viruses in fresh produce. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Hydrologic, abiotic and biotic interactions: plant density, windspeed, leaf size and groundwater all affect oak water use efficiency

Science.gov (United States)

Darin J. Law; Deborah M. Finch

2011-01-01

Plant water use in drylands can be complex due to variation in hydrologic, abiotic and biotic factors, particularly near ephemeral or intermittent streams. Plant use of groundwater may be important but is usually uncertain. Disturbances like fire contribute to complex spatiotemporal heterogeneity. Improved understanding of how such hydrologic, abiotic, and biotic...

Regulation of Translation Initiation under Biotic and Abiotic Stresses

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Ana B. Castro-Sanz

2013-02-01

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

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

Science.gov (United States)

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

2015-03-01

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

Roles of arabidopsis WRKY18, WRKY40 and WRKY60 transcription factors in plant responses to abscisic acid and abiotic stress

OpenAIRE

Chen Zhixiang; Xiao Yong; Shi Junwei; Lai Zhibing; Chen Han; Xu Xinping

2010-01-01

Abstract Background WRKY transcription factors are involved in plant responses to both biotic and abiotic stresses. Arabidopsis WRKY18, WRKY40, and WRKY60 transcription factors interact both physically and functionally in plant defense responses. However, their role in plant abiotic stress response has not been directly analyzed. Results We report that the three WRKYs are involved in plant responses to abscisic acid (ABA) and abiotic stress. Through analysis of single, double, and triple muta...

Exchange of adsorbed serum proteins during adhesion of Staphylococcus aureus to an abiotic surface and Candida albicans hyphae--an AFM study.

Science.gov (United States)

Ovchinnikova, Ekaterina S; van der Mei, Henny C; Krom, Bastiaan P; Busscher, Henk J

2013-10-01

Staphylococcus aureus and Candida albicans are the second and third most commonly isolated microorganisms in hospital-related-infections, that are often multi-species in nature causing high morbidity and mortality. Here, adhesion forces between a S. aureus strain and abiotic (tissue-culture-polystyrene, TCPS) or partly biotic (TCPS with adhering hyphae of C. albicans) surfaces were investigated in presence of fetal-bovine-serum or individual serum proteins and related with staphylococcal adhesion. Atomic-force-microscopy was used to measure adhesion forces between S. aureus and the abiotic and biotic surfaces. Adsorption of individual serum proteins like albumin and apo-transferrin to abiotic TCPS surfaces during 60min, impeded development of strong adhesion forces as compared to fibronectin, while 60min adsorption of proteins from fetal-bovine-serum yielded a decrease in adhesion force from -5.7nN in phosphate-buffered-saline to -0.6nN. Adsorption of albumin and apo-transferrin also decreased staphylococcal adhesion forces to hyphae as compared with fibronectin. During 60min exposure to fetal-bovine-serum however, initial (5min protein adsorption) staphylococcal adhesion forces were low (-1.6nN), but strong adhesion forces of around -5.5nN were restored within 60min. This suggests for the first time that in whole fetal-bovine-serum exchange of non-adhesive proteins by fibronectin occurs on biotic C. albicans hyphal surfaces. No evidence was found for such protein exchange on abiotic TCPS surfaces. Staphylococcal adhesion of abiotic and biotic surfaces varied in line with the adhesion forces and was low on TCPS in presence of fetal-bovine-serum. On partly biotic TCPS, staphylococci aggregated in presence of fetal-bovine-serum around adhering C. albicans hyphae. Copyright © 2013 Elsevier B.V. All rights reserved.

Characterization of Rice Homeobox Genes, OsHOX22 and OsHOX24, and Over-expression of OsHOX24 in Transgenic Arabidopsis Suggest their Role in Abiotic Stress Response

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Annapurna eBhattacharjee

2016-05-01

Full Text Available Homeobox transcription factors are well known regulators of plant growth and development. In this study, we carried out functional analysis of two candidate stress-responsive HD-ZIP I class homeobox genes from rice, OsHOX22 and OsHOX24. These genes were highly upregulated under various abiotic stress conditions at different stages of rice development, including seedling, mature and reproductive stages. The transcript levels of these genes were enhanced significantly in the presence of plant hormones, including abscisic acid (ABA, auxin, salicylic acid and gibberellic acid. The recombinant full-length and truncated homeobox proteins were found to be localized in the nucleus. Electrophoretic mobility shift assay established the binding of these homeobox proteins with specific DNA sequences, AH1 (CAAT(A/TATTG and AH2 (CAAT(C/GATTG. Transactivation assays in yeast revealed the transcriptional activation potential of full-length OsHOX22 and OsHOX24 proteins. Homo- and hetero-dimerization capabilities of these proteins have also been demonstrated. Further, we identified putative novel interacting proteins of OsHOX22 and OsHOX24 via yeast-two hybrid analysis. Over-expression of OsHOX24 imparted higher sensitivity to stress hormone, ABA, and abiotic stresses in the transgenic Arabidopsis plants as revealed by various physiological and phenotypic assays. Microarray analysis revealed differential expression of several stress-responsive genes in transgenic lines as compared to wild-type. Many of these genes were found to be involved in transcriptional regulation and various metabolic pathways. Altogether, our results suggest the possible role of OsHOX22/OsHOX24 homeobox proteins as negative regulators in abiotic stress responses.

AVP1: One Protein, Many Roles

KAUST Repository

Schilling, Rhiannon K.

2016-12-16

Constitutive expression of the Arabidopsis vacuolar proton-pumping pyrophosphatase (H+-PPase) gene (AVP1) increases plant growth under various abiotic stress conditions and, importantly, under nonstressed conditions. Many interpretations have been proposed to explain these phenotypes, including greater vacuolar ion sequestration, increased auxin transport, enhanced heterotrophic growth, and increased transport of sucrose from source to sink tissues. In this review, we evaluate all the roles proposed for AVP1, using findings published to date from mutant plants lacking functional AVP1 and transgenic plants expressing AVP1. It is clear that AVP1 is one protein with many roles, and that one or more of these roles act to enhance plant growth. The complexity suggests that a systems biology approach to evaluate biological networks is required to investigate these intertwined roles.

AVP1: One Protein, Many Roles

KAUST Repository

Schilling, Rhiannon K.; Tester, Mark A.; Marschner, Petra; Plett, Darren C.; Roy, Stuart J.

2016-01-01

Constitutive expression of the Arabidopsis vacuolar proton-pumping pyrophosphatase (H+-PPase) gene (AVP1) increases plant growth under various abiotic stress conditions and, importantly, under nonstressed conditions. Many interpretations have been proposed to explain these phenotypes, including greater vacuolar ion sequestration, increased auxin transport, enhanced heterotrophic growth, and increased transport of sucrose from source to sink tissues. In this review, we evaluate all the roles proposed for AVP1, using findings published to date from mutant plants lacking functional AVP1 and transgenic plants expressing AVP1. It is clear that AVP1 is one protein with many roles, and that one or more of these roles act to enhance plant growth. The complexity suggests that a systems biology approach to evaluate biological networks is required to investigate these intertwined roles.

Overexpression of GmHsp90s, a heat shock protein 90 (Hsp90 gene family cloning from soybean, decrease damage of abiotic stresses in Arabidopsis thaliana.

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Jinyan Xu

Full Text Available Hsp90 is one of the most conserved and abundant molecular chaperones and is an essential component of the protective stress response; however, its roles in abiotic stress responses in soybean (Glycine max remain obscure. Here, 12 GmHsp90 genes from soybean were identified and found to be expressed and to function differentially under abiotic stresses. The 12 GmHsp90 genes were isolated and named GmHsp90A1-GmHsp90A6, GmHsp90B1, GmHsp90B2, GmHsp90C1.1, GmHsp90C1.2, GmHsp90C2.1 and GmHsp90C2.2 based on their characteristics and high homology to other Hsp90s according to a new nomenclature system. Quantitative real-time PCR expression data revealed that all the genes exhibited higher transcript levels in leaves and could be strongly induced under heat, osmotic and salt stress but not cold stress. Overexpression of five typical genes (GmHsp90A2, GmHsp90A4, GmHsp90B1, GmHsp90C1.1 and GmHsp90C2.1 in Arabidopsis thaliana provided useful evidences that GmHsp90 genes can decrease damage of abiotic stresses. In addition, an abnormal accumulation of proline was detected in some transgenic Arabidopsis plants suggested overexpressing GmHsp90s may affect the synthesis and response system of proline. Our work represents a systematic determination of soybean genes encoding Hsp90s, and provides useful evidence that GmHsp90 genes function differently in response to abiotic stresses and may affect the synthesis and response system of proline.

Assessment of derelict soil quality: Abiotic, biotic and functional approaches.

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Vincent, Quentin; Auclerc, Apolline; Beguiristain, Thierry; Leyval, Corinne

2018-02-01

The intensification and subsequent closing down of industrial activities during the last century has left behind large surfaces of derelict lands. Derelict soils have low fertility, can be contaminated, and many of them remain unused. However, with the increasing demand of soil surfaces, they might be considered as a resource, for example for non-food biomass production. The study of their physico-chemical properties and of their biodiversity and biological activity may provide indications for their potential re-use. The objective of our study was to investigate the quality of six derelict soils, considering abiotic, biotic, and functional parameters. We studied (i) the soil bacteria, fungi, meso- and macro-fauna and plant communities of six different derelict soils (two from coking plants, one from a settling pond, two constructed ones made from different substrates and remediated soil, and an inert waste storage one), and (ii) their decomposition function based on the decomposer trophic network, enzyme activities, mineralization activity, and organic pollutant degradation. Biodiversity levels in these soils were high, but all biotic parameters, except the mycorrhizal colonization level, discriminated them. Multivariate analysis showed that biotic parameters co-varied more with fertility proxies than with soil contamination parameters. Similarly, functional parameters significantly co-varied with abiotic parameters. Among functional parameters, macro-decomposer proportion, enzyme activity, average mineralization capacity, and microbial polycyclic aromatic hydrocarbon degraders were useful to discriminate the soils. We assessed their quality by combining abiotic, biotic, and functional parameters: the compost-amended constructed soil displayed the highest quality, while the settling pond soil and the contaminated constructed soil displayed the lowest. Although differences among the soils were highlighted, this study shows that derelict soils may provide a

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

Science.gov (United States)

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.

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

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Nasar Virk

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

Phytoplankton and some abiotic features of El-Bardawil Lake, Sinai ...

African Journals Online (AJOL)

Phytoplankton and some abiotic features of El-Bardawil Lake, Sinai, Egypt. H Touliabah, HM Safik, MM Gab-Allah, WD Taylor. Abstract. El-Bardawil Lake is a large coastal lagoon on the Mediterranean coast of Sinai, Egypt. Although it is shallow and oligotrophic, it is one of the most important lakes in Egypt as a source of ...

Influence of abiotic stresses on the winter wheat sprouting plants

Czech Academy of Sciences Publication Activity Database

Bláha, L.; Hnilička, F.; Kadlec, P.; Smrčková-Jankovská, P.; Macháčková, Ivana; Sychrová, E.; Kohout, Ladislav

2008-01-01

Roč. 3, č. 3 (2008), s. 389-390 ISSN 1125-4718. [Congress of the European Society for Agronomy /10./. 15.09.2008-19.09.2008, Bologna] R&D Projects: GA MZe QF3056 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z40550506 Keywords : brassinosteroids * abiotic stress * emergency Subject RIV: CC - Organic Chemistry

Cross-family translational genomics of abiotic stress-responsive genes between Arabidopsis and Medicago truncatula.

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Daejin Hyung

Full Text Available Cross-species translation of genomic information may play a pivotal role in applying biological knowledge gained from relatively simple model system to other less studied, but related, genomes. The information of abiotic stress (ABS-responsive genes in Arabidopsis was identified and translated into the legume model system, Medicago truncatula. Various data resources, such as TAIR/AtGI DB, expression profiles and literatures, were used to build a genome-wide list of ABS genes. tBlastX/BlastP similarity search tools and manual inspection of alignments were used to identify orthologous genes between the two genomes. A total of 1,377 genes were finally collected and classified into 18 functional criteria of gene ontology (GO. The data analysis according to the expression cues showed that there was substantial level of interaction among three major types (i.e., drought, salinity and cold stress of abiotic stresses. In an attempt to translate the ABS genes between these two species, genomic locations for each gene were mapped using an in-house-developed comparative analysis platform. The comparative analysis revealed that fragmental colinearity, represented by only 37 synteny blocks, existed between Arabidopsis and M. truncatula. Based on the combination of E-value and alignment remarks, estimated translation rate was 60.2% for this cross-family translation. As a prelude of the functional comparative genomic approaches, in-silico gene network/interactome analyses were conducted to predict key components in the ABS responses, and one of the sub-networks was integrated with corresponding comparative map. The results demonstrated that core members of the sub-network were well aligned with previously reported ABS regulatory networks. Taken together, the results indicate that network-based integrative approaches of comparative and functional genomics are important to interpret and translate genomic information for complex traits such as abiotic stresses.

Differentiating biotic from abiotic methane genesis in hydrothermally active planetary surfaces.

Science.gov (United States)

Oze, Christopher; Jones, L Camille; Goldsmith, Jonas I; Rosenbauer, Robert J

2012-06-19

Molecular hydrogen (H(2)) is derived from the hydrothermal alteration of olivine-rich planetary crust. Abiotic and biotic processes consume H(2) to produce methane (CH(4)); however, the extent of either process is unknown. Here, we assess the temporal dependence and limit of abiotic CH(4) related to the presence and formation of mineral catalysts during olivine hydrolysis (i.e., serpentinization) at 200 °C and 0.03 gigapascal. Results indicate that the rate of CH(4) production increases to a maximum value related to magnetite catalyzation. By identifying the dynamics of CH(4) production, we kinetically model how the H(2) to CH(4) ratio may be used to assess the origin of CH(4) in deep subsurface serpentinization systems on Earth and Mars. Based on our model and available field data, low H(2)/CH(4) ratios (less than approximately 40) indicate that life is likely present and active.

Overexpression of AtEDT1/HDG11 in Chinese Kale (Brassica oleracea var. alboglabra) Enhances Drought and Osmotic Stress Tolerance.

Science.gov (United States)

Zhu, Zhangsheng; Sun, Binmei; Xu, Xiaoxia; Chen, Hao; Zou, Lifang; Chen, Guoju; Cao, Bihao; Chen, Changming; Lei, Jianjun

2016-01-01

Plants are constantly challenged by environmental stresses, including drought and high salinity. Improvement of drought and osmotic stress tolerance without yield decrease has been a great challenge in crop improvement. The Arabidopsis ENHANCED DROUGHT TOLERANCE1/HOMEODOMAIN GLABROUS11 (AtEDT1/HDG11), a protein of the class IV HD-Zip family, has been demonstrated to significantly improve drought tolerance in Arabidopsis, rice, and pepper. Here, we report that AtEDT1/HDG11 confers drought and osmotic stress tolerance in the Chinese kale. AtEDT1/HDG11-overexpression lines exhibit auxin-overproduction phenotypes, such as long hypocotyls, tall stems, more root hairs, and a larger root system architecture. Compared with the untransformed control, transgenic lines have significantly reduced stomatal density. In the leaves of transgenic Chinese kale plants, proline (Pro) content and reactive oxygen species-scavenging enzyme activity was significantly increased after drought and osmotic stress, particularly compared to wild kale. More importantly, AtEDT1/HDG11-overexpression leads to abscisic acid (ABA) hypersensitivity, resulting in ABA inhibitor germination and induced stomatal closure. Consistent with observed phenotypes, the expression levels of auxin, ABA, and stress-related genes were also altered under both normal and/or stress conditions. Further analysis showed that AtEDT1/HDG11, as a transcription factor, can target the auxin biosynthesis gene YUCC6 and ABA response genes ABI3 and ABI5. Collectively, our results provide a new insight into the role of AtEDT1/HDG11 in enhancing abiotic stress resistance through auxin- and ABA-mediated signaling response in Chinese kale.

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

Institute of Scientific and Technical Information of China (English)

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

2011-01-01

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

Primordial soup was edible: abiotically produced Miller-Urey mixture supports bacterial growth.

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Xie, Xueshu; Backman, Daniel; Lebedev, Albert T; Artaev, Viatcheslav B; Jiang, Liying; Ilag, Leopold L; Zubarev, Roman A

2015-09-28

Sixty years after the seminal Miller-Urey experiment that abiotically produced a mixture of racemized amino acids, we provide a definite proof that this primordial soup, when properly cooked, was edible for primitive organisms. Direct admixture of even small amounts of Miller-Urey mixture strongly inhibits E. coli bacteria growth due to the toxicity of abundant components, such as cyanides. However, these toxic compounds are both volatile and extremely reactive, while bacteria are highly capable of adaptation. Consequently, after bacterial adaptation to a mixture of the two most abundant abiotic amino acids, glycine and racemized alanine, dried and reconstituted MU soup was found to support bacterial growth and even accelerate it compared to a simple mixture of the two amino acids. Therefore, primordial Miller-Urey soup was perfectly suitable as a growth media for early life forms.

A comparison between acoustic properties and heat effects in biogenic (magnetosomes) and abiotic magnetite nanoparticle suspensions

International Nuclear Information System (INIS)

Józefczak, A.; Leszczyński, B.; Skumiel, A.; Hornowski, T.

2016-01-01

Magnetic nanoparticles show unique properties and find many applications because of the possibility to control their properties using magnetic field. Magnetic nanoparticles are usually synthesized chemically and modification of the particle surface is necessary. Another source of magnetic nanoparticles are various magnetotactic bacteria. These biogenic nanoparticles (magnetosomes) represent an attractive alternative to chemically synthesized iron oxide particles because of their unique characteristics and a high potential for biotechnological and biomedical applications. This work presents a comparison between acoustic properties of biogenic and abiotic magnetite nanoparticle suspensions. Experimental studies have shown the influence of a biological membrane on the ultrasound properties of magnetosomes suspension. Finally the heat effect in synthetic and biogenic magnetite nanoparticles is also discussed. The experimental study shows that magnetosomes present good heating efficiency. - Highlights: • A biogenic and abiotic magnetite nanoparticle suspensions are investigated. • A comparison between ultrasonic properties and heat effects is presented. • Magnetosomes and abiotic magnetite nanoparticles exhibit good heating efficiency.

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

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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.

Titania may produce abiotic oxygen atmospheres on habitable exoplanets

OpenAIRE

Norio Narita; Takafumi Enomoto; Shigeyuki Masaoka; Nobuhiko Kusakabe

2015-01-01

The search for habitable exoplanets in the Universe is actively ongoing in the field of astronomy. The biggest future milestone is to determine whether life exists on such habitable exoplanets. In that context, oxygen in the atmosphere has been considered strong evidence for the presence of photosynthetic organisms. In this paper, we show that a previously unconsidered photochemical mechanism by titanium (IV) oxide (titania) can produce abiotic oxygen from liquid water under near ultraviolet ...

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

Science.gov (United States)

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

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

NARCIS (Netherlands)

Kissoudis, C.

2016-01-01

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

Strategies for Distinguishing Abiotic Chemistry from Martian Biochemistry in Samples Returned from Mars

Science.gov (United States)

Glavin, D. P.; Burton, A. S.; Callahan, M. P.; Elsila, J. E.; Stern, J. C.; Dworkin, J. P.

2012-01-01

A key goal in the search for evidence of extinct or extant life on Mars will be the identification of chemical biosignatures including complex organic molecules common to all life on Earth. These include amino acids, the monomer building blocks of proteins and enzymes, and nucleobases, which serve as the structural basis of information storage in DNA and RNA. However, many of these organic compounds can also be formed abiotically as demonstrated by their prevalence in carbonaceous meteorites [1]. Therefore, an important challenge in the search for evidence of life on Mars will be distinguishing between abiotic chemistry of either meteoritic or martian origin from any chemical biosignatures from an extinct or extant martian biota. Although current robotic missions to Mars, including the 2011 Mars Science Laboratory (MSL) and the planned 2018 ExoMars rovers, will have the analytical capability needed to identify these key classes of organic molecules if present [2,3], return of a diverse suite of martian samples to Earth would allow for much more intensive laboratory studies using a broad array of extraction protocols and state-of-theart analytical techniques for bulk and spatially resolved characterization, molecular detection, and isotopic and enantiomeric compositions that may be required for unambiguous confirmation of martian life. Here we will describe current state-of-the-art laboratory analytical techniques that have been used to characterize the abundance and distribution of amino acids and nucleobases in meteorites, Apollo samples, and comet- exposed materials returned by the Stardust mission with an emphasis on their molecular characteristics that can be used to distinguish abiotic chemistry from biochemistry as we know it. The study of organic compounds in carbonaceous meteorites is highly relevant to Mars sample return analysis, since exogenous organic matter should have accumulated in the martian regolith over the last several billion years and the

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

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Yingjie Yu

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

Cytosine Methylation Alteration in Natural Populations of Leymus chinensis Induced by Multiple Abiotic Stresses

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Yu, Yingjie; Yang, Xuejiao; Wang, Huaying; Shi, Fengxue; Liu, Ying; Liu, Jushan; Li, Linfeng; Wang, Deli; Liu, Bao

2013-01-01

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

Genome-wide identification and analysis of biotic and abiotic stress regulation of small heat shock protein (HSP20) family genes in bread wheat.

Science.gov (United States)

Muthusamy, Senthilkumar K; Dalal, Monika; Chinnusamy, Viswanathan; Bansal, Kailash C

2017-04-01

Small Heat Shock Proteins (sHSPs)/HSP20 are molecular chaperones that protect plants by preventing protein aggregation during abiotic stress conditions, especially heat stress. Due to global climate change, high temperature is emerging as a major threat to wheat productivity. Thus, the identification of HSP20 and analysis of HSP transcriptional regulation under different abiotic stresses in wheat would help in understanding the role of these proteins in abiotic stress tolerance. We used sequences of known rice and Arabidopsis HSP20 HMM profiles as queries against publicly available wheat genome and wheat full length cDNA databases (TriFLDB) to identify the respective orthologues from wheat. 163 TaHSP20 (including 109 sHSP and 54 ACD) genes were identified and classified according to the sub-cellular localization and phylogenetic relationship with sequenced grass genomes (Oryza sativa, Sorghum bicolor, Zea mays, Brachypodium distachyon and Setaria italica). Spatio-temporal, biotic and abiotic stress-specific expression patterns in normalized RNA seq and wheat array datasets revealed constitutive as well as inductive responses of HSP20 in different tissues and developmental stages of wheat. Promoter analysis of TaHSP20 genes showed the presence of tissue-specific, biotic, abiotic, light-responsive, circadian and cell cycle-responsive cis-regulatory elements. 14 TaHSP20 family genes were under the regulation of 8 TamiRNA genes. The expression levels of twelve HSP20 genes were studied under abiotic stress conditions in the drought- and heat-tolerant wheat genotype C306. Of the 13 TaHSP20 genes, TaHSP16.9H-CI showed high constitutive expression with upregulation only under salt stress. Both heat and salt stresses upregulated the expression of TaHSP17.4-CI, TaHSP17.7A-CI, TaHSP19.1-CIII, TaACD20.0B-CII and TaACD20.6C-CIV, while TaHSP23.7-MTI was specifically induced only under heat stress. Our results showed that the identified TaHSP20 genes play an important role under

The Importance of Biotic vs. Abiotic Drivers of Local Plant Community Composition Along Regional Bioclimatic Gradients.

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Kari Klanderud

Full Text Available We assessed if the relative importance of biotic and abiotic factors for plant community composition differs along environmental gradients and between functional groups, and asked which implications this may have in a warmer and wetter future. The study location is a unique grid of sites spanning regional-scale temperature and precipitation gradients in boreal and alpine grasslands in southern Norway. Within each site we sampled vegetation and associated biotic and abiotic factors, and combined broad- and fine-scale ordination analyses to assess the relative explanatory power of these factors for species composition. Although the community responses to biotic and abiotic factors did not consistently change as predicted along the bioclimatic gradients, abiotic variables tended to explain a larger proportion of the variation in species composition towards colder sites, whereas biotic variables explained more towards warmer sites, supporting the stress gradient hypothesis. Significant interactions with precipitation suggest that biotic variables explained more towards wetter climates in the sub alpine and boreal sites, but more towards drier climates in the colder alpine. Thus, we predict that biotic interactions may become more important in alpine and boreal grasslands in a warmer future, although more winter precipitation may counteract this trend in oceanic alpine climates. Our results show that both local and regional scales analyses are needed to disentangle the local vegetation-environment relationships and their regional-scale drivers, and biotic interactions and precipitation must be included when predicting future species assemblages.

De novo transcriptome sequence assembly and identification of AP2/ERF transcription factor related to abiotic stress in parsley (Petroselinum crispum.

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Meng-Yao Li

Full Text Available Parsley is an important biennial Apiaceae species that is widely cultivated as herb, spice, and vegetable. Previous studies on parsley principally focused on its physiological and biochemical properties, including phenolic compound and volatile oil contents. However, little is known about the molecular and genetic properties of parsley. In this study, 23,686,707 high-quality reads were obtained and assembled into 81,852 transcripts and 50,161 unigenes for the first time. Functional annotation showed that 30,516 unigenes had sequence similarity to known genes. In addition, 3,244 putative simple sequence repeats were detected in curly parsley. Finally, 1,569 of the identified unigenes belonged to 58 transcription factor families. Various abiotic stresses have a strong detrimental effect on the yield and quality of parsley. AP2/ERF transcription factors have important functions in plant development, hormonal regulation, and abiotic response. A total of 88 putative AP2/ERF factors were identified from the transcriptome sequence of parsley. Seven AP2/ERF transcription factors were selected in this study to analyze the expression profiles of parsley under different abiotic stresses. Our data provide a potentially valuable resource that can be used for intensive parsley research.

De novo transcriptome sequence assembly and identification of AP2/ERF transcription factor related to abiotic stress in parsley (Petroselinum crispum).

Science.gov (United States)

Li, Meng-Yao; Tan, Hua-Wei; Wang, Feng; Jiang, Qian; Xu, Zhi-Sheng; Tian, Chang; Xiong, Ai-Sheng

2014-01-01

Parsley is an important biennial Apiaceae species that is widely cultivated as herb, spice, and vegetable. Previous studies on parsley principally focused on its physiological and biochemical properties, including phenolic compound and volatile oil contents. However, little is known about the molecular and genetic properties of parsley. In this study, 23,686,707 high-quality reads were obtained and assembled into 81,852 transcripts and 50,161 unigenes for the first time. Functional annotation showed that 30,516 unigenes had sequence similarity to known genes. In addition, 3,244 putative simple sequence repeats were detected in curly parsley. Finally, 1,569 of the identified unigenes belonged to 58 transcription factor families. Various abiotic stresses have a strong detrimental effect on the yield and quality of parsley. AP2/ERF transcription factors have important functions in plant development, hormonal regulation, and abiotic response. A total of 88 putative AP2/ERF factors were identified from the transcriptome sequence of parsley. Seven AP2/ERF transcription factors were selected in this study to analyze the expression profiles of parsley under different abiotic stresses. Our data provide a potentially valuable resource that can be used for intensive parsley research.

SEASONALITY OF THE LEAF MINER, LEVEL OF PREDATION AND TEMPORAL OCCURRENCE OF RUST CORRELATED TO ABIOTIC FACTORS

OpenAIRE

B. M. R. Melo; F. B. S. Botelho; J. S. M. Silva; D. F. F. Lima; E. R. Moreira

2018-01-01

The coffee leaf miner and a rust are considered as major diseases that are able to reduce productivity in coffee plantations. These agents are influenced by abiotic factors, and their occurrence may suffer oscillation over the years. The objective of this study was to evaluate the seasonal fluctuation of the coffee leaf miner, incidence of coffee prediction and rust, correlated with abiotic factors. The study was performed IFSULDEMINAS-Campus Inconfidentes, in a coffee crop of the cultivar Ru...

Global Transcriptome Analysis of Combined Abiotic Stress Signaling Genes Unravels Key Players in Oryza sativa L.: An In silico Approach

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Pandiyan Muthuramalingam

2017-05-01

Full Text Available Combined abiotic stress (CAbS affects the field grown plants simultaneously. The multigenic and quantitative nature of uncontrollable abiotic stresses complicates the process of understanding the stress response by plants. Considering this, we analyzed the CAbS response of C3 model plant, Oryza sativa by meta-analysis. The datasets of commonly expressed genes by drought, salinity, submergence, metal, natural expression, biotic, and abiotic stresses were data mined through publically accessible transcriptomic abiotic stress (AbS responsive datasets. Of which 1,175, 12,821, and 42,877 genes were commonly expressed in meta differential, individual differential, and unchanged expressions respectively. Highly regulated 100 differentially expressed AbS genes were derived through integrative meta-analysis of expression data (INMEX. Of this 30 genes were identified from AbS gene families through expression atlas that were computationally analyzed for their physicochemical properties. All AbS genes were physically mapped against O. sativa genome. Comparative mapping of these genes demonstrated the orthologous relationship with related C4 panicoid genome. In silico expression analysis of these genes showed differential expression patterns in different developmental tissues. Protein–protein interaction of these genes, represented the complexity of AbS. Computational expression profiling of candidate genes in response to multiple stresses suggested the putative involvement of OS05G0350900, OS02G0612700, OS05G0104200, OS03G0596200, OS12G0225900, OS07G0152000, OS08G0119500, OS06G0594700, and Os01g0393100 in CAbS. These potential candidate genes need to be studied further to decipher their functional roles in AbS dynamics.

Tamarix hispida zinc finger protein ThZFP1 participates in salt and osmotic stress tolerance by increasing proline content and SOD and POD activities.

Science.gov (United States)

Zang, Dandan; Wang, Chao; Ji, Xiaoyu; Wang, Yucheng

2015-06-01

Zinc finger proteins (ZFPs) are a large family that play important roles in various biological processes, such as signal transduction, RNA binding, morphogenesis, transcriptional regulation, abiotic or biotic stress response. However, the functions of ZFPs involved in abiotic stress are largely not known. In the present study, we cloned and functionally characterized a ZFP gene, ThZFP1, from Tamarix hispida. The expression of ThZFP1 is highly induced by NaCl, mannitol or ABA treatment. To study the function of ThZFP1 involved in abiotic stress response, transgenic T. hispida plants with overexpression or knockdown of ThZFP1 were generated using a transient transformation system. Gain- and loss-of-function studies of ThZFP1 suggested that ThZFP1 can induce the expression of a series of genes, including delta-pyrroline-5-carboxylate synthetase (P5CS), peroxidase (POD) and superoxide dismutase (SOD), leading to accumulation of proline and enhanced activities of SOD and POD. These physiological changes enhanced proline content and reactive oxygen species (ROS) scavenging capability when exposed to salt or osmotic stress. All the results obtained from T. hispida plants were further confirmed by analyses of the transgenic Arabidopsis plants overexpressing ThZFP1. These data together suggested that ThZFP1 positively regulates proline accumulation and activities of SOD and POD under salt and osmotic stress conditions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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.

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

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S. M. Nuruzzaman Manik

2015-01-01

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

Abiotic environmental conditions for germination and development of gametophytes of Cyathea phalerata Mart. (Cyatheaceae

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Catiuscia Marcon

Full Text Available ABSTRACT In order to successfully establish themselves in their natural environment, ferns need habitats with abiotic conditions that are suitable for spore germination and gametophyte development. The objective of this study was to assess the influence of abiotic factors on the initial development of Cyathea phalerata cultivated in vitro. Spore germination and gametophyte development were assessed under varying conditions of surface sterilization, pH, temperature and photoperiod. Exogenous contamination was eliminated by sterilizing spores with 2.5 % NaClO for 15 min and sowing them into a culture medium supplemented with nystatin. Spores germinated at all pHs tested. Gametophytic development was faster in acidic pHs. Cultures at 25 °C exhibited the highest percentages of germination and laminar gametophytes. The species produced its highest percentages of gametophytes in cultures with photoperiods between 6 and 18 h. The optimal abiotic conditions found here for in vitro development of C. phalerata are similar to those found in its natural habitat. The southern limit of this species to north of the 30th parallel in Rio Grande do Sul, Brazil, may be because further south spores do not encounter the ideal combined conditions of temperature, pH and photoperiod determined in the laboratory.

Abiotic and seasonal control of soil-produced CO2 efflux in karstic ecosystems located in Oceanic and Mediterranean climates

Science.gov (United States)

Garcia-Anton, Elena; Cuezva, Soledad; Fernandez-Cortes, Angel; Alvarez-Gallego, Miriam; Pla, Concepcion; Benavente, David; Cañaveras, Juan Carlos; Sanchez-Moral, Sergio

2017-09-01

This study characterizes the processes involved in seasonal CO2 exchange between soils and shallow underground systems and explores the contribution of the different biotic and abiotic sources as a function of changing weather conditions. We spatially and temporally investigated five karstic caves across the Iberian Peninsula, which presented different microclimatic, geologic and geomorphologic features. The locations present Mediterranean and Oceanic climates. Spot air sampling of CO2 (g) and δ13CO2 in the caves, soils and outside atmospheric air was periodically conducted. The isotopic ratio of the source contribution enhancing the CO2 concentration was calculated using the Keeling model. We compared the isotopic ratio of the source in the soil (δ13Cs-soil) with that in the soil-underground system (δ13Cs-system). Although the studied field sites have different features, we found common seasonal trends in their values, which suggests a climatic control over the soil air CO2 and the δ13CO2 of the sources of CO2 in the soil (δ13Cs-soil) and the system (δ13Cs-system). The roots respiration and soil organic matter degradation are the main source of CO2 in underground environments, and the inlet of the gas is mainly driven by diffusion and advection. Drier and warmer conditions enhance soil-exterior CO2 interchange, reducing the CO2 concentration and increasing the δ13CO2 of the soil air. Moreover, the isotopic ratio of the source of CO2 in both the soil and the system tends to heavier values throughout the dry and warm season. We conclude that seasonal variations of soil CO2 concentration and its 13C/12C isotopic ratio are mainly regulated by thermo-hygrometric conditions. In cold and wet seasons, the increase of soil moisture reduces soil diffusivity and allows the storage of CO2 in the subsoil. During dry and warm seasons, the evaporation of soil water favours diffusive and advective transport of soil-derived CO2 to the atmosphere. The soil CO2 diffusion is

Enhanced dissolution of TCE in NAPL by TCE-degrading bacteria in wetland soils

International Nuclear Information System (INIS)

Lee, Sangjin

2007-01-01

The influence of trichloroethene (TCE) dechlorinating mixed cultures in dissolution of TCE in nonaqueous phase liquid (NAPL) via biodegradation was observed. Experiments were conducted in batch reactor system with and without marsh soils under 10 and 20 deg. C for 2 months. The dissolution phenomenon in biotic reactors containing mixed cultures was showed temporal increases compared to abiotic reactors treated with biocide. Effective NAPL-water transfer rate (K m ) calculated in this study showed more than four times higher in biotic reactors than that in abiotic reactors. The results might be attributed to the biologically enhanced dissolution process via dechlorination in reactors. Temperature would be a factor to determine the dissolution rate by controlling bacterial activity. The TCE dechlorination occurred even in an interface of TCE-NAPL that demonstrated no previous TCE biodegradation, suggesting that microbes may be useful in developing source-zone bioremediation system. In conclusion, dechlorinating mixed culture could enhance dissolution in NAPL that may be useful in the application of source zone bioremediation

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-04-15

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

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

Science.gov (United States)

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.

Asymmetric biotic interactions and abiotic niche differences revealed by a dynamic joint species distribution model.

Science.gov (United States)

Lany, Nina K; Zarnetske, Phoebe L; Schliep, Erin M; Schaeffer, Robert N; Orians, Colin M; Orwig, David A; Preisser, Evan L

2018-05-01

A species' distribution and abundance are determined by abiotic conditions and biotic interactions with other species in the community. Most species distribution models correlate the occurrence of a single species with environmental variables only, and leave out biotic interactions. To test the importance of biotic interactions on occurrence and abundance, we compared a multivariate spatiotemporal model of the joint abundance of two invasive insects that share a host plant, hemlock woolly adelgid (HWA; Adelges tsugae) and elongate hemlock scale (EHS; Fiorina externa), to independent models that do not account for dependence among co-occurring species. The joint model revealed that HWA responded more strongly to abiotic conditions than EHS. Additionally, HWA appeared to predispose stands to subsequent increase of EHS, but HWA abundance was not strongly dependent on EHS abundance. This study demonstrates how incorporating spatial and temporal dependence into a species distribution model can reveal the dependence of a species' abundance on other species in the community. Accounting for dependence among co-occurring species with a joint distribution model can also improve estimation of the abiotic niche for species affected by interspecific interactions. © 2018 by the Ecological Society of America.

Role of Biotic and Abiotic Processes on Soil CO2 Dynamics in the McMurdo Dry Valleys, Antarctica

Science.gov (United States)

Risk, D. A.; Macintyre, C. M.; Lee, C.; Cary, C.; Shanhun, F.; Almond, P. C.

2016-12-01

In the harsh conditions of the Antarctic Dry Valleys, microbial activity has been recorded via measurements of soil carbon dioxide (CO2) concentration and surface efflux. However, high temporal resolution studies in the Dry Valleys have also shown that abiotic solubility-driven processes can strongly influence (and perhaps even dominate) the CO2 dynamics in these low flux environments and suggests that biological activity may be lower than previously thought. In this study, we aim to improve our understanding of CO2 dynamics (biotic and abiotic) in Antarctic Dry Valley soils using long-term automated measurements of soil CO2 surface flux and soil profile concentration at several sites, often at sub-diel frequency. We hypothesize that soil CO2 variations are driven primarily by environmental factors affecting CO2 solubility in soil solution, mainly temperature, and that these processes may even overprint biologic production in representative Dry Valley soils. Monitoring of all sites revealed only one likely biotic CO2 production event, lasting three weeks during the Austral summer and reaching fluxes of 0.4 µmol/m2/s. Under more typical low flux conditions (sampling campaigns. Subsurface CO2 monitoring and a lab-controlled Antarctic soil simulation experiment confirmed that abiotic processes are capable of dominating soil CO2 variability. Diel temperature cycles crossing the freezing boundary revealed a dual abiotic cycle of solubility cycling and gas exclusion from ice formation observed only by high temporal frequency measurements (30 min). This work demonstrates a need for a numerical model to partition the dynamic abiotic processes underlying any biotic CO2 production in order to understand potential climate-change induced increases in microbial productivity in terrestrial Antarctica.

Differential contributions to the transcriptome of duplicated genes in response to abiotic stresses in natural and synthetic polyploids.

Science.gov (United States)

Dong, Shaowei; Adams, Keith L

2011-06-01

Polyploidy has occurred throughout plant evolution and can result in considerable changes to gene expression when it takes place and over evolutionary time. Little is known about the effects of abiotic stress conditions on duplicate gene expression patterns in polyploid plants. We examined the expression patterns of 60 duplicated genes in leaves, roots and cotyledons of allotetraploid Gossypium hirsutum in response to five abiotic stress treatments (heat, cold, drought, high salt and water submersion) using single-strand conformation polymorphism assays, and 20 genes in a synthetic allotetraploid. Over 70% of the genes showed stress-induced changes in the relative expression levels of the duplicates under one or more stress treatments with frequent variability among treatments. Twelve pairs showed opposite changes in expression levels in response to different abiotic stress treatments. Stress-induced expression changes occurred in the synthetic allopolyploid, but there was little correspondence in patterns between the natural and synthetic polyploids. Our results indicate that abiotic stress conditions can have considerable effects on duplicate gene expression in a polyploid, with the effects varying by gene, stress and organ type. Differential expression in response to environmental stresses may be a factor in the preservation of some duplicated genes in polyploids. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

Overexpression of SoCYP85A1, a Spinach Cytochrome p450 Gene in Transgenic Tobacco Enhances Root Development and Drought Stress Tolerance

Directory of Open Access Journals (Sweden)

Fangmeng Duan

2017-11-01

Full Text Available Brassinosteroids (BRs play an essential role in plant growth, development, and responses to diverse abiotic stresses. However, previous studies mainly analyzed how exogenous BRs influenced plant physiological reactions to drought stress, therefore, genetic evidences for the endogenous BRs-mediated regulation of plant responses still remain elusive. In this study, a key BRs biosynthetic gene, SoCYP85A1 was cloned from Spinacia oleracea, which has a complete open reading frame of 1,392 bp encoding a 464 amino acid peptide and shares high sequence similarities with CYP85A1 from other plants. The expression of SoCYP85A1 which was higher in leaf compared with root and stem, was induced by treatments of PEG6000, abscisic acid (ABA, low temperature and high salt. Increases in both SoCYP85A1 transcripts and endogenous BRs in transgenic tobacco which resulted in longer primary root and more lateral roots enhanced drought tolerance compared with wild types. The transgenic tobacco accumulated much lower levels of reactive oxygen species and malondialdehyde (MDA than wild types did, accompanied by significantly higher content of proline and notably enhanced activities of antioxidant enzymes. Besides, transcriptional expressions of six stress-responsive genes were regulated to higher levels in transgenic lines under drought stress. Taken together, our results demonstrated that SoCYP85A1 involves in response to drought stress by promoting root development, scavenging ROS, and regulating expressions of stress-responsive genes.

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

Science.gov (United States)

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

2015-01-01

Regulation of root architecture is essential for maintaining plant growth under adverse environment. A synthetic abscisic acid (ABA)/stress-inducible promoter was designed to control the expression of a late embryogenesis abundant protein (HVA1) in transgenic rice. The background of HVA1 is low but highly inducible by ABA, salt, dehydration and cold. HVA1 was highly accumulated in root apical meristem (RAM) and lateral root primordia (LRP) after ABA/stress treatments, leading to enhanced root system expansion. Water-use efficiency (WUE) and biomass also increased in transgenic rice, likely due to the maintenance of normal cell functions and metabolic activities conferred by HVA1 which is capable of stabilizing proteins, under osmotic stress. HVA1 promotes lateral root (LR) initiation, elongation and emergence and primary root (PR) elongation via an auxin-dependent process, particularly by intensifying asymmetrical accumulation of auxin in LRP founder cells and RAM, even under ABA/stress-suppressive conditions. We demonstrate a successful application of an inducible promoter in regulating the spatial and temporal expression of HVA1 for improving root architecture and multiple stress tolerance without yield penalty. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Plant Responses to Abiotic Stress Regulated by Histone Deacetylases

Directory of Open Access Journals (Sweden)

Ming Luo

2017-12-01

Full Text Available In eukaryotic cells, histone acetylation and deacetylation play an important role in the regulation of gene expression. Histone acetylation levels are modulated by histone acetyltransferases and histone deacetylases (HDACs. Recent studies indicate that HDACs play essential roles in the regulation of gene expression in plant response to environmental stress. In this review, we discussed the recent advance regarding the plant HDACs and their functions in the regulation of abiotic stress responses. The role of HDACs in autophagy was also discussed.

Synthesis of the DDT metabolite 2,4-dichloro-1-[2-chloro-1-(4-chlorophenyl)ethenyl]benzene (o-Cl-DDMU) and its detection in abiotic and biotic samples.

Science.gov (United States)

Gallistl, Christoph; Proctor, Katie; Bader, Korinna; Vetter, Walter

2017-07-01

Technical dichlorodiphenyltrichloroethane (DDT) has been used worldwide as a pesticide since the beginning of the 1940s. Due to its persistence, DDT residues are still ubiquitously distributed in the environment. Photochemical UV degradation has been shown to be a potent degradation path for DDT and most of the resulting photoproducts have been identified up to now. Nevertheless, in 2012, a new DDT metabolite, most likely formed photochemically from DDE, was detected in ray liver samples from Brazil, an area which is highly contaminated with DDT. This study includes photochemical generation, chemical synthesis and isolation of this compound which was verified to consist of both cis- and trans-2,4-dichloro-1-[2-chloro-1-(4-chlorophenyl)ethenyl]benzene. Both stereoisomers were resolved by gas chromatography on a polar capillary column and detected in more than 60 biotic (e.g. marine mammals, birds, human milk) and abiotic samples (fat deposits in kitchen hoods) from different areas all over the world. The stereoisomer distribution and concentrations (0.3-3.9% relative to corresponding 1,1-dichloro-2,2-bis(p-chlorophenyl) ethane (p,p'-DDE) levels) were determined by means of the synthesized analytical standard, indicating the widespread occurrence of this compound as an additional minor metabolite of DDT.

The inner Danish waters as suitable seaweed cultivation area- evaluation of abiotic factors

DEFF Research Database (Denmark)

Grandorf Bak, Urd; Holdt, Susan Løvstad

conditions showed, that light conditions are sufficient to meet the light saturation level of both algae, but large seasonal and a site specific variations in light attenuation determine optimal cultivation depth. Water temperatures were found to exceed the tolerance level for P. palmata in July, August......Increased production of macroalgae may contribute to solving e.g. the demand for food globally. Palmaria palmata and Saccharina latissima are at present demanded and cultivated in European waters, and can potentially be cultivated at even larger scale. The present study investigated suitable...... cultivation areas in Danish waters for these two algal species in regard to a variation in the abiotic conditions: light, temperature, and the unusual salinity gradient through the inner Danish waters towards the Baltic Sea. Published tolerance levels of the abiotic conditions of the species were reviewed...

Enhancing drought tolerance in C(4) crops.

Science.gov (United States)

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.

Flowering phenology, growth forms, and pollination syndromes in tropical dry forest species: Influence of phylogeny and abiotic factors.

Science.gov (United States)

Cortés-Flores, Jorge; Hernández-Esquivel, Karen Beatriz; González-Rodríguez, Antonio; Ibarra-Manríquez, Guillermo

2017-01-01

Analyses of the influence of temporal variation in abiotic factors on flowering phenology of tropical dry forest species have not considered the possible response of species with different growth forms and pollination syndromes, while controlling for phylogenetic relationships among species. Here, we investigated the relationship between flowering phenology, abiotic factors, and plant functional attributes, while controlling for phylogenetic relationship among species, in a dry forest community in Mexico. We characterized flowering phenology (time and duration) and pollination syndromes of 55 tree species, 49 herbs, 24 shrubs, 15 lianas, and 11 vines. We tested the influence of pollination syndrome, growth form, and abiotic factors on flowering phenology using phylogenetic generalized least squares. We found a relationship between flowering duration and time. Growth form was related to flowering time, and the pollination syndrome had a more significant relationship with flowering duration. Flowering time variation in the community was explained mainly by abiotic variables, without an important phylogenetic effect. Flowering time in lianas and trees was negatively and positively correlated with daylength, respectively. Functional attributes, environmental cues, and phylogeny interact with each other to shape the diversity of flowering patterns. Phenological differentiation among species groups revealed multiples strategies associated with growth form and pollination syndromes that can be important for understanding species coexistence in this highly diverse plant community. © 2017 Botanical Society of America.

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

Science.gov (United States)

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

2016-08-04

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

Methane-bearing fluids in subduction zones: an experimental study of abiotic methanogenesis during serpentinization at 12 kbar and 300°C

Science.gov (United States)

Lazar, C.; Manning, C. E.

2009-12-01

Serpentinization within subduction zones may generate reduced fluids that contain higher concentrations of abiotic methane than near-surface ultramafic environments. We present preliminary experimental data suggesting that the kinetics of abiotic methanogenesis are enhanced at high pressures. Thermodynamic calculations of C-O-H fluid speciations at the low oxygen fugacities attained during early serpentinization suggest complete conversion of oxidized carbon to methane, yet previous field and experimental investigations have reported fluid compositions with CH4/CO2 far below equilibrium (McCollom and Seewald, 2007). Much experimental work, therefore, has focused on CH4 production rates and the kinetic effects of temperature and mineral catalysis (Horita and Berdt, 1999; Foustoukos and Seyfried, 2004). Methane has been shown experimentally to form at very high pressures (Scott et al, 2004), but the quantitative effect of pressure on methanogenesis kinetics is unknown. We present preliminary results of a comparison of methane production rates at 0.35 and 12 kbar, 300°C, using experiments performed in piston cylinder and cold seal hydrothermal apparatus. Carbon was introduced as a roughly 70 mmol solution of isotopically-labeled formic acid, H13COOH, known to decompose to 13CO2 and H2 at run conditions. Roughly 15 mL of this solution, along with 1.9 mg of natural awaruite (Ni3Fe), was loaded into a gold capsule and then sealed via DC spot welding. Awaruite, a known methane catalyst (Horita and Berndt, 1999), was added to increase the overall rates of all experiments in order to boost the concentration for analysis and as an fO2 buffer appropriate for serpentinization. The experiments were held at T and P for approximately 160 hours. After each run, the capsule was placed in a gas vial and punctured with a needle. The contents of the vial were extracted via gas syringe and injected into gas chromatograph mass spectrometer (GC-MS). CH4 concentration in the 12 kbar run

Abiotic and biotic controls over biogeochemical cycles in drylands: Insights from climate change and nitrogen deposition experiments on the Colorado Plateau

Science.gov (United States)

Reed, S.; Ferrenberg, S.; Tucker, C.; Rutherford, W. A.; Wertin, T. M.; McHugh, T. A.; Morrissey, E.; Kuske, C.; Mueller, R.; Belnap, J.

2016-12-01

As for all ecosystems, biogeochemical cycling in drylands represents numerous intricate connections between biotic and abiotic controls. However, patterns of many fundamental ecosystem processes that generally hold across global gradients fall apart at the arid and semiarid end of the spectrum, and data point to an exceptionally strong role for abiotic controls in explaining these patterns. Further, there are multiple dryland characteristics - such as extreme aridity and high UV radiation, as well as specialized biological communities - which can point to a conclusion that "drylands are different". Indeed, drylands are often characterized by their harsh environment, by the diverse classes of biota representing a range of traits aimed at surviving such harsh conditions, and, more recently, by the suggestion of dramatic biotic responses to seemingly subtle changes in abiotic factors. In this talk, we will explore a range of biotic and abiotic controls over fundamental biogeochemical cycling in drylands using data from a suite of manipulation experiments on the Colorado Plateau, USA. We will present results from field treatments that speak to the effects of increasing temperature, altered precipitation regimes, increased nitrogen availability via deposition, and the effects of altered litterfall inputs. Biogeochemical processes we explore will include plant photosynthesis, soil photosynthesis and respiration (with a focus on biological soil crusts), litter decomposition, and nutrient cycling. In addition, we will assess how treatments alter dryland community composition, as well as the resultant feedbacks of community shifts to environmental change. Taken together we will use these diverse datasets to ask questions about what makes drylands different or, instead, if a holistic joining of biotic and abiotic perspectives suggests they are not so different after all. These data will not only lend insight into the partitioning of and balance between biotic and abiotic

26 CFR 1.43-1 - The enhanced oil recovery credit-general rules.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 1 2010-04-01 2010-04-01 true The enhanced oil recovery credit-general rules. 1... INCOME TAXES Credits Against Tax § 1.43-1 The enhanced oil recovery credit—general rules. (a) Claiming the credit—(1) In general. The enhanced oil recovery credit (the “credit”) is a component of the...

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

KAUST Repository

Rungrat, Tepsuda

2016-09-09

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

Abiotic mechanism for the formation of atmospheric nitrous oxide from ammonium nitrate.

Science.gov (United States)

Rubasinghege, Gayan; Spak, Scott N; Stanier, Charles O; Carmichael, Gregory R; Grassian, Vicki H

2011-04-01

Nitrous oxide (N2O) is an important greenhouse gas and a primary cause of stratospheric ozone destruction. Despite its importance, there remain missing sources in the N2O budget. Here we report the formation of atmospheric nitrous oxide from the decomposition of ammonium nitrate via an abiotic mechanism that is favorable in the presence of light, relative humidity and a surface. This source of N2O is not currently accounted for in the global N2O budget. Annual production of N2O from atmospheric aerosols and surface fertilizer application over the continental United States from this abiotic pathway is estimated from results of an annual chemical transport simulation with the Community Multiscale Air Quality model (CMAQ). This pathway is projected to produce 9.3(+0.7/-5.3) Gg N2O annually over North America. N2O production by this mechanism is expected globally from both megacities and agricultural areas and may become more important under future projected changes in anthropogenic emissions.

Contrast-enhanced turbo spin-echo(TSE) T1-weighted imaging: improved contrast of enhancing lesions

International Nuclear Information System (INIS)

Choi, Sung Wook; Lee, Ghi Jai; Shim, Jae Chan; Lee, Young Ju; Jeong, Se Hyung; Kim, Ho kyun

1997-01-01

The purpose of this study was to evaluate the effect of contrast improvement of enhancing brain lesions by inherent magnetization transfer effect in turbo spin-echo(TSE)T1-weighted MR imaging. Twenty-six enhancing lesions of 19 patients were included in this study. Using a 1.0T superconductive MR unit, contrast-enhanced SE T1-weighted images(TR=3D600 msec, TE=3D12 msec, NEX=3D2, acquistition time=3D4min 27sec) and contrast-enhanced TSE T1-weighted images(TR=3D600 msec, TE=3D12, acquistition time=3D1min 44sec) were obtained. Signal intensities at enhancing lesions and adjacent white matter were measured in the same regions of both images. Signal-to-noise ratio(SNR) of enhancing lesions and adjacent white matter, and con-trast-to-noise ratio(CNR) and lesion-to-background contrast (LBC) of enhancing lesions were calculated and statistically analysed using the paired t-test. On contrast-enhanced TSE T1-weighted images, SNR of enhancing lesions and adjacent white matter decreased by 18%(p<0.01) and 32%(p<0.01), respectively, compared to contrast-enhanced SE T1-weighted images. CNR and LBC of enhancing lesions increased by 16%(p<0.05) and 66%(p<0.01), respectively. Due to the proposed inherent magnetization transfer effects in TSE imaging, con-trast-enhanced T1-weighted TSE images demonstrated a statistically significant improvement in CNR and LBC, compared to conventional contrast-enhanced T1-weighted SE images, and scan time was much shorter

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

S-Nitrosylated proteins in pea (Pisum sativum L.) leaf peroxisomes: changes under abiotic stress.

Science.gov (United States)

Ortega-Galisteo, Ana P; Rodríguez-Serrano, María; Pazmiño, Diana M; Gupta, Dharmendra K; Sandalio, Luisa M; Romero-Puertas, María C

2012-03-01

Peroxisomes, single-membrane-bounded organelles with essentially oxidative metabolism, are key in plant responses to abiotic and biotic stresses. Recently, the presence of nitric oxide (NO) described in peroxisomes opened the possibility of new cellular functions, as NO regulates diverse biological processes by directly modifying proteins. However, this mechanism has not yet been analysed in peroxisomes. This study assessed the presence of S-nitrosylation in pea-leaf peroxisomes, purified S-nitrosylated peroxisome proteins by immunoprecipitation, and identified the purified proteins by two different mass-spectrometry techniques (matrix-assisted laser desorption/ionization tandem time-of-flight and two-dimensional nano-liquid chromatography coupled to ion-trap tandem mass spectrometry). Six peroxisomal proteins were identified as putative targets of S-nitrosylation involved in photorespiration, β-oxidation, and reactive oxygen species detoxification. The activity of three of these proteins (catalase, glycolate oxidase, and malate dehydrogenase) is inhibited by NO donors. NO metabolism/S-nitrosylation and peroxisomes were analysed under two different types of abiotic stress, i.e. cadmium and 2,4-dichlorophenoxy acetic acid (2,4-D). Both types of stress reduced NO production in pea plants, and an increase in S-nitrosylation was observed in pea extracts under 2,4-D treatment while no total changes were observed in peroxisomes. However, the S-nitrosylation levels of catalase and glycolate oxidase changed under cadmium and 2,4-D treatments, suggesting that this post-translational modification could be involved in the regulation of H(2)O(2) level under abiotic stress.

Abiotic factors in colony formation: effects of nutrition and light on extracellular polysaccharide production and cell aggregates of Microcystis aeruginosa

Science.gov (United States)

Yang, Zhen; Kong, Fanxiang

2013-07-01

Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes. The mechanism of colony formation in Microcystis is currently unclear. Extracellular polysaccharide (EPS) has been reported to play an important role in cell aggregate formation of some phytoplankton. Microcystis aeruginosa was cultivated under varied abiotic conditions, including different nutrient, light, and temperature conditions, to investigate their effects on EPS production and morphological change. The results show that nutrient concentration and light intensity have great effects on EPS productionin M. aeruginosa. There was a considerable increase in EPS production after M. aeruginosa was cultivated in adjusted culture conditions similar to those present in the field (28.9 mg C/L, 1.98 mg N/L, 0.65 mg P/L, light intensity: 100 μmol/(m2 · s)). These results indicate that abiotic factors might be one of the triggers for colony formation in Microcystis.

Metabolite Profiling and Transcript Analysis Reveal Specificities in the Response of a Berry Derived Cell Culture to Abiotic Stresses

Directory of Open Access Journals (Sweden)

Biruk eAyenew

2015-09-01

Full Text Available As climate changes, there is a need to understand the expected effects on viticulture. In nature, stresses exist in a combined manner, hampering the elucidation of the effect of individual cues on grape berry metabolism. Cell suspension culture originated from pea-size Gamy Red grape berry was used to harness metabolic response to high light (2500 µmol m-2s-1, high temperature (40 0C and their combination in comparison to 25 0C and 100 µmol m-2s-1 under controlled condition. When LC-MS and GC-MS based metabolite profiling was implemented and integrated with targeted RT-qPCR transcript analysis specific responses were observed to the different cues. High light enhanced polyphenol metabolism while high temperature and its combination with high light induced amino acid and organic acid metabolism with additional effect on polyphenols. The trend of increment in TCA cycle genes like ATCs, ACo1 and IDH in the combined treatment might support the observed increment in organic acids, GABA shunt, and their derivatives. The apparent phenylalanine reduction with polyphenol increment under high light suggests enhanced fueling of the precursor towards the downstream phenylpropanoid pathway. In the polyphenol metabolism, a differential pattern of expression of flavonoid 3’,5’ hydroxylase and flavonoid 3’ hydroxylase was observed under high light and combined cues which were accompanied by characteristic metabolite profiles. High temperature decreased glycosylated cyanidin and peonidin forms while the combined cues increased acetylated and coumarylated peonidin forms. Transcription factors regulating anthocyanin metabolism and their methylation, MYB, OMT, UFGT and DFR, were expressed differentially among the treatments, overall in agreement with the metabolite profiles. Taken together these data provide insights into the coordination of central and secondary metabolism in relation to multiple abiotic stresses.

Suitable Reference Genes for Accurate Gene Expression Analysis in Parsley (Petroselinum crispum) for Abiotic Stresses and Hormone Stimuli.

Science.gov (United States)

Li, Meng-Yao; Song, Xiong; Wang, Feng; Xiong, Ai-Sheng

2016-01-01

Parsley, one of the most important vegetables in the Apiaceae family, is widely used in the food, medicinal, and cosmetic industries. Recent studies on parsley mainly focus on its chemical composition, and further research involving the analysis of the plant's gene functions and expressions is required. qPCR is a powerful method for detecting very low quantities of target transcript levels and is widely used to study gene expression. To ensure the accuracy of results, a suitable reference gene is necessary for expression normalization. In this study, four software, namely geNorm, NormFinder, BestKeeper, and RefFinder were used to evaluate the expression stabilities of eight candidate reference genes of parsley ( GAPDH, ACTIN, eIF-4 α, SAND, UBC, TIP41, EF-1 α, and TUB ) under various conditions, including abiotic stresses (heat, cold, salt, and drought) and hormone stimuli treatments (GA, SA, MeJA, and ABA). Results showed that EF-1 α and TUB were the most stable genes for abiotic stresses, whereas EF-1 α, GAPDH , and TUB were the top three choices for hormone stimuli treatments. Moreover, EF-1 α and TUB were the most stable reference genes among all tested samples, and UBC was the least stable one. Expression analysis of PcDREB1 and PcDREB2 further verified that the selected stable reference genes were suitable for gene expression normalization. This study can guide the selection of suitable reference genes in gene expression in parsley.

Suitable reference genes for accurate gene expression analysis in parsley (Petroselinum crispum for abiotic stresses and hormone stimuli

Directory of Open Access Journals (Sweden)

Meng-Yao Li

2016-09-01

Full Text Available Parsley is one of the most important vegetable in Apiaceae family and widely used in food industry, medicinal and cosmetic. The recent studies in parsley are mainly focus on chemical composition, further research involving the analysis of the gene functions and expressions will be required. qPCR is a powerful method for detecting very low quantities of target transcript levels and widely used for gene expression studies. To ensure the accuracy of results, a suitable reference gene is necessary for expression normalization. In this study, three software geNorm, NormFinder, and BestKeeper were used to evaluate the expression stabilities of eight candidate reference genes (GAPDH, ACTIN, eIF-4α, SAND, UBC, TIP41, EF-1α, and TUB under various conditions including abiotic stresses (heat, cold, salt, and drought and hormone stimuli treatments (GA, SA, MeJA, and ABA. The results showed that EF-1α and TUB were identified as the most stable genes for abiotic stresses, while EF-1α, GAPDH, and TUB were the top three choices for hormone stimuli treatments. Moreover, EF-1α and TUB were the most stable reference genes across all the tested samples, while UBC was the least stable one. The expression analysis of PcDREB1 and PcDREB2 further verified that the selected stable reference genes were suitable for gene expression normalization. This study provides a guideline for selection the suitable reference genes in gene expression in parsley.

Alternative Splicing Control of Abiotic Stress Responses.

Science.gov (United States)

Laloum, Tom; Martín, Guiomar; Duque, Paula

2018-02-01

Alternative splicing, which generates multiple transcripts from the same gene, is an important modulator of gene expression that can increase proteome diversity and regulate mRNA levels. In plants, this post-transcriptional mechanism is markedly induced in response to environmental stress, and recent studies have identified alternative splicing events that allow rapid adjustment of the abundance and function of key stress-response components. In agreement, plant mutants defective in splicing factors are severely impaired in their response to abiotic stress. Notably, mounting evidence indicates that alternative splicing regulates stress responses largely by targeting the abscisic acid (ABA) pathway. We review here current understanding of post-transcriptional control of plant stress tolerance via alternative splicing and discuss research challenges for the near future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mud, Macrofauna and Microbes: An ode to benthic organism-abiotic interactions at varying scales

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Benthic environments are dynamic habitats, subject to variable sources and rates of sediment delivery, reworking from the abiotic and biotic processes, and complex biogeochemistry. These activities do not occur in a vacuum, and interact synergistically to influence food webs, bi...

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.

SiASR4, the Target Gene of SiARDP from Setaria italica, Improves Abiotic Stress Adaption in Plants.

Science.gov (United States)

Li, Jianrui; Dong, Yang; Li, Cong; Pan, Yanlin; Yu, Jingjuan

2016-01-01

Drought and other types of abiotic stresses negatively affect plant growth and crop yields. The abscisic acid-, stress-, and ripening-induced (ASR) proteins play important roles in the protection of plants against abiotic stress. However, the regulatory pathway of the gene encoding this protein remains to be elucidated. In this study, the foxtail millet ( Setaria italica ) ASR gene, SiASR4 , was cloned and characterized. SiASR4 localized to the cell nucleus, cytoplasm and cytomembrane, and the protein contained 102 amino acids, including an ABA/WDS (abscisic acid/water-deficit stress) domain, with a molecular mass of 11.5 kDa. The abundance of SiASR4 transcripts increased after treatment with ABA, NaCl, and PEG in foxtail millet seedlings. It has been reported that the S. italica ABA-responsive DRE-binding protein (SiARDP) binds to a DNA sequence with a CCGAC core and that there are five dehydration-responsive element (DRE) motifs within the SiASR4 promoter. Our analyses demonstrated that the SiARDP protein could bind to the SiASR4 promoter in vitro and in vivo . The expression of SiASR4 increased in SiARDP -overexpressing plants. SiASR4 -transgenic Arabidopsis and SiASR4 -overexpressing foxtail millet exhibited enhanced tolerance to drought and salt stress. Furthermore, the transcription of stress-responsive and reactive oxygen species (ROS) scavenger-associated genes was activated in SiASR4 transgenic plants. Together, these findings show that SiASR4 functions in the adaption to drought and salt stress and is regulated by SiARDP via an ABA-dependent pathway.

Simulation of enhanced in-situ biorestoration of petroleum hydrocarbons

International Nuclear Information System (INIS)

Borden, R.C.

1991-01-01

This paper discusses a general mathematical model being developed to aid in the design and analysis of projects for the enhanced aerobic bioremediation of petroleum-contaminated aquifers. Development of the enhanced biotransformation model is proceeding in three steps: development of an abiotic hydrocarbon dissolution model; coupling the dissolution model with existing equations for simulating aerobic biodegradation; and comparison with laboratory data. The model assumes that the residual hydrocarbon is distributed between two fractions, a fast fraction in equilibrium with the aqueous phase and a slow fraction in which mass transfer is limited. Overall, the model provides an excellent fit to the experimental data and requires a minimum of input parameters

Spatial variability of biotic and abiotic tree establishment constraints across a treeline ecotone in the Alaska range.

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Stueve, Kirk M; Isaacs, Rachel E; Tyrrell, Lucy E; Densmore, Roseann V

2011-02-01

Throughout interior Alaska (U.S.A.), a gradual warming trend in mean monthly temperatures occurred over the last few decades (approximatlely 2-4 degrees C). The accompanying increases in woody vegetation at many alpine treeline (hereafter treeline) locations provided an opportunity to examine how biotic and abiotic local site conditions interact to control tree establishment patterns during warming. We devised a landscape ecological approach to investigate these relationships at an undisturbed treeline in the Alaska Range. We identified treeline changes between 1953 (aerial photography) and 2005 (satellite imagery) in a geographic information system (GIS) and linked them with corresponding local site conditions derived from digital terrain data, ancillary climate data, and distance to 1953 trees. Logistic regressions enabled us to rank the importance of local site conditions in controlling tree establishment. We discovered a spatial transition in the importance of tree establishment controls. The biotic variable (proximity to 1953 trees) was the most important tree establishment predictor below the upper tree limit, providing evidence of response lags with the abiotic setting and suggesting that tree establishment is rarely in equilibrium with the physical environment or responding directly to warming. Elevation and winter sun exposure were important predictors of tree establishment at the upper tree limit, but proximity to trees persisted as an important tertiary predictor, indicating that tree establishment may achieve equilibrium with the physical environment. However, even here, influences from the biotic variable may obscure unequivocal correlations with the abiotic setting (including temperature). Future treeline expansion will likely be patchy and challenging to predict without considering the spatial variability of influences from biotic and abiotic local site conditions.

RING E3 ligases: key regulatory elements are involved in abiotic stress responses in plants.

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Cho, Seok Keun; Ryu, Moon Young; Kim, Jong Hum; Hong, Jeong Soo; Oh, Tae Rin; Kim, Woo Taek; Yang, Seong Wook

2017-08-01

Plants are constantly exposed to a variety of abiotic stresses, such as drought, heat, cold, flood, and salinity. To survive under such unfavorable conditions, plants have evolutionarily developed their own resistant-mechanisms. For several decades, many studies have clarified specific stress response pathways of plants through various molecular and genetic studies. In particular, it was recently discovered that ubiquitin proteasome system (UPS), a regulatory mechanism for protein turn over, is greatly involved in the stress responsive pathways. In the UPS, many E3 ligases play key roles in recognizing and tethering poly-ubiquitins on target proteins for subsequent degradation by the 26S proteasome. Here we discuss the roles of RING ligases that have been defined in related to abiotic stress responses in plants. [BMB Reports 2017; 50(8): 393-400].

Maternal, social and abiotic environmental effects on growth vary across life stages in a cooperative mammal.

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English, Sinead; Bateman, Andrew W; Mares, Rafael; Ozgul, Arpat; Clutton-Brock, Tim H

2014-03-01

Resource availability plays a key role in driving variation in somatic growth and body condition, and the factors determining access to resources vary considerably across life stages. Parents and carers may exert important influences in early life, when individuals are nutritionally dependent, with abiotic environmental effects having stronger influences later in development as individuals forage independently. Most studies have measured specific factors influencing growth across development or have compared relative influences of different factors within specific life stages. Such studies may not capture whether early-life factors continue to have delayed effects at later stages, or whether social factors change when individuals become nutritionally independent and adults become competitors for, rather than providers of, food. Here, we examined variation in the influence of the abiotic, social and maternal environment on growth across life stages in a wild population of cooperatively breeding meerkats. Cooperatively breeding vertebrates are ideal for investigating environmental influences on growth. In addition to experiencing highly variable abiotic conditions, cooperative breeders are typified by heterogeneity both among breeders, with mothers varying in age and social status, and in the number of carers present. Recent rainfall had a consistently marked effect on growth across life stages, yet other seasonal terms only influenced growth during stages when individuals were growing fastest. Group size and maternal dominance status had positive effects on growth during the period of nutritional dependence on carers, but did not influence mass at emergence (at 1 month) or growth at independent stages (>4 months). Pups born to older mothers were lighter at 1 month of age and subsequently grew faster as subadults. Males grew faster than females during the juvenile and subadult stage only. Our findings demonstrate the complex ways in which the external environment

Genome-wide characterization of the WRKY gene family in radish (Raphanus sativus L.) reveals its critical functions under different abiotic stresses.

Science.gov (United States)

Karanja, Bernard Kinuthia; Fan, Lianxue; Xu, Liang; Wang, Yan; Zhu, Xianwen; Tang, Mingjia; Wang, Ronghua; Zhang, Fei; Muleke, Everlyne M'mbone; Liu, Liwang

2017-11-01

The radish WRKY gene family was genome-widely identified and played critical roles in response to multiple abiotic stresses. The WRKY is among the largest transcription factors (TFs) associated with multiple biological activities for plant survival, including control response mechanisms against abiotic stresses such as heat, salinity, and heavy metals. Radish is an important root vegetable crop and therefore characterization and expression pattern investigation of WRKY transcription factors in radish is imperative. In the present study, 126 putative WRKY genes were retrieved from radish genome database. Protein sequence and annotation scrutiny confirmed that RsWRKY proteins possessed highly conserved domains and zinc finger motif. Based on phylogenetic analysis results, RsWRKYs candidate genes were divided into three groups (Group I, II and III) with the number 31, 74, and 20, respectively. Additionally, gene structure analysis revealed that intron-exon patterns of the WRKY genes are highly conserved in radish. Linkage map analysis indicated that RsWRKY genes were distributed with varying densities over nine linkage groups. Further, RT-qPCR analysis illustrated the significant variation of 36 RsWRKY genes under one or more abiotic stress treatments, implicating that they might be stress-responsive genes. In total, 126 WRKY TFs were identified from the R. sativus genome wherein, 35 of them showed abiotic stress-induced expression patterns. These results provide a genome-wide characterization of RsWRKY TFs and baseline for further functional dissection and molecular evolution investigation, specifically for improving abiotic stress resistances with an ultimate goal of increasing yield and quality of radish.

Glycinebetaine synthesizing transgenic potato plants exhibit enhanced tolerance to salt and cold stresses

International Nuclear Information System (INIS)

Ahmad, R.; Hussain, J.

2014-01-01

Abiotic stresses are the most important contributors towards low productivity of major food crops. Various attempts have been made to enhance abiotic stress tolerance of crop plants by classical breeding and genetic transformation. Genetic transformation with glycinebetaine (GB) synthesizing enzymes' gene(s) in naturally non accumulating plants has resulted in enhanced tolerance against variety of abiotic stresses. Present study was aimed to evaluate the performance of GB synthesizing transgenic potato plants against salt and cold stresses. Transgenic potato plants were challenged against salt and cold stresses at whole plant level. Transgenic lines were characterized to determine the transgene copy number. Different parameters like integrity, chlorophyll contents, tuber yield and vegetative biomass were studied to monitor the stress tolerance of transgenic potato plants. The results were compared with Non-transgenic (NT) plants and statistically analyzed to evaluate significant differences. Multi-copy insertion of expression cassette was found in both transgenic lines. Upon salt stress, transgenic plants maintained better growth as compared to NT plants. The tuber yield of transgenic plants was significantly greater than NT plants in salt stress. Transgenic plants showed improved membrane integrity against cold stress by depicting appreciably reduced ion leakage as compared to NT plants. Moreover, transgenic plants showed significantly less chlorophyll bleaching than NT plants upon cold stress. In addition, NT plants accumulated significantly less biomass, and yielded fewer tubers as compared to transgenic plants after cold stress treatment. The study will be a committed step for field evaluation of transgenic plants with the aim of commercialization. (author)

Abiotic degradation of plastic films

Science.gov (United States)

Ángeles-López, Y. G.; Gutiérrez-Mayen, A. M.; Velasco-Pérez, M.; Beltrán-Villavicencio, M.; Vázquez-Morillas, A.; Cano-Blanco, M.

2017-01-01

Degradable plastics have been promoted as an option to mitigate the environmental impacts of plastic waste. However, there is no certainty about its degradability under different environmental conditions. The effect of accelerated weathering (AW), natural weathering (NW) and thermal oxidation (TO) on different plastics (high density polyethylene, HDPE; oxodegradable high density polyethylene, HDPE-oxo; compostable plastic, Ecovio ® metalized polypropylene, PP; and oxodegradable metalized polypropylene, PP-oxo) was studied. Plastics films were exposed to AW per 110 hours; to NW per 90 days; and to TO per 30 days. Plastic films exposed to AW and NW showed a general loss on mechanical properties. The highest reduction in elongation at break on AW occurred to HDPE-oxo (from 400.4% to 20.9%) and was higher than 90% for HDPE, HDPE-oxo, Ecovio ® and PP-oxo in NW. No substantial evidence of degradation was found on plastics exposed to TO. Oxo-plastics showed higher degradation rates than their conventional counterparts, and the compostable plastic was resistant to degradation in the studied abiotic conditions. This study shows that degradation of plastics in real life conditions will vary depending in both, their composition and the environment.

Validation of potential reference genes for qPCR in maize across abiotic stresses, hormone treatments, and tissue types.

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Yueai Lin

Full Text Available The reverse transcription quantitative polymerase chain reaction (RT-qPCR is a powerful and widely used technique for the measurement of gene expression. Reference genes, which serve as endogenous controls ensure that the results are accurate and reproducible, are vital for data normalization. To bolster the literature on reference gene selection in maize, ten candidate reference genes, including eight traditionally used internal control genes and two potential candidate genes from our microarray datasets, were evaluated for expression level in maize across abiotic stresses (cold, heat, salinity, and PEG, phytohormone treatments (abscisic acid, salicylic acid, jasmonic acid, ethylene, and gibberellins, and different tissue types. Three analytical software packages, geNorm, NormFinder, and Bestkeeper, were used to assess the stability of reference gene expression. The results revealed that elongation factor 1 alpha (EF1α, tubulin beta (β-TUB, cyclophilin (CYP, and eukaryotic initiation factor 4A (EIF4A were the most reliable reference genes for overall gene expression normalization in maize, while GRP (Glycine-rich RNA-binding protein, GLU1(beta-glucosidase, and UBQ9 (ubiquitin 9 were the least stable and most unsuitable genes. In addition, the suitability of EF1α, β-TUB, and their combination as reference genes was confirmed by validating the expression of WRKY50 in various samples. The current study indicates the appropriate reference genes for the urgent requirement of gene expression normalization in maize across certain abiotic stresses, hormones, and tissue types.

A nonspecific Setaria italica lipid transfer protein gene plays a critical role under abiotic stress

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Yanlin Pan

2016-11-01

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

Intracranial arterial wall enhancement using gadolinium-enhanced 3D black-blood T1-weighted imaging

Energy Technology Data Exchange (ETDEWEB)

Takano, Koichi, E-mail: k-takano@fukuoka-u.ac.jp; Hida, Kosuke; Kuwabara, Yasuo; Yoshimitsu, Kengo

2017-01-15

Purpose: We investigated the enhancement of the intracranial arterial walls with gadolinium-enhanced, black-blood three-dimensional T1-weighted imaging (Gd-3DBB) by using an improved motion-sensitized driven-equilibrium (iMSDE)—prepared volumetric isotropic turbo spin-echo acquisition (VISTA). Methods: A total of 115 patients underwent FLAIR, 3D-TOF-MRA and Gd-3DBB with a 1.5-T scanner. The degree and distribution of the arterial wall enhancement on Gd-3DBB was assessed. The association of the degree of wall enhancement with brain infarction/ischemic lesions on FLAIR, luminal changes on 3D-TOF-MRA, and cardiovascular risk factors (CVRFs) was investigated by univariate and multiple logistic regression analyses. Results: Strong enhancement of the arterial walls was observed in 77 vertebral arteries (33.5%), 4 basilar arteries (3.5%), 31 supraclinoid internal carotid arteries (ICAs) (13.5%) and 8 middle cerebral arteries (3.5%). In addition, 221 intrapetrous ICAs (96.1%) showed strong enhancement. After adjusting for confounding factors, multivariate analyses showed that the patient age was independently associated with the strong wall enhancement of the arteries for both the posterior (OR, 1.088; 95% CI, 1.034–1.146) and the anterior circulation (OR, 1.098, 95% CI 1.029–1.172). In addition, the presence of the supratentorial brain infarctions was independently associated with the strong wall enhancement in the anterior circulation excluding the intrapetrous ICAs (OR, 4.097; 95% CI, 1.483–11.319). Conclusions: Although the arterial wall enhancement on the Gd-3DBB probably reflects normal aging, the enhancement in the anterior circulation might be related to brain infarctions. On the other hand, the intrapetrous ICA enhancement is considered a nonspecific finding and should not be mistaken for arterial pathologies such as atherosclerosis or arteritis.

Intracranial arterial wall enhancement using gadolinium-enhanced 3D black-blood T1-weighted imaging

International Nuclear Information System (INIS)

Takano, Koichi; Hida, Kosuke; Kuwabara, Yasuo; Yoshimitsu, Kengo

2017-01-01

Purpose: We investigated the enhancement of the intracranial arterial walls with gadolinium-enhanced, black-blood three-dimensional T1-weighted imaging (Gd-3DBB) by using an improved motion-sensitized driven-equilibrium (iMSDE)—prepared volumetric isotropic turbo spin-echo acquisition (VISTA). Methods: A total of 115 patients underwent FLAIR, 3D-TOF-MRA and Gd-3DBB with a 1.5-T scanner. The degree and distribution of the arterial wall enhancement on Gd-3DBB was assessed. The association of the degree of wall enhancement with brain infarction/ischemic lesions on FLAIR, luminal changes on 3D-TOF-MRA, and cardiovascular risk factors (CVRFs) was investigated by univariate and multiple logistic regression analyses. Results: Strong enhancement of the arterial walls was observed in 77 vertebral arteries (33.5%), 4 basilar arteries (3.5%), 31 supraclinoid internal carotid arteries (ICAs) (13.5%) and 8 middle cerebral arteries (3.5%). In addition, 221 intrapetrous ICAs (96.1%) showed strong enhancement. After adjusting for confounding factors, multivariate analyses showed that the patient age was independently associated with the strong wall enhancement of the arteries for both the posterior (OR, 1.088; 95% CI, 1.034–1.146) and the anterior circulation (OR, 1.098, 95% CI 1.029–1.172). In addition, the presence of the supratentorial brain infarctions was independently associated with the strong wall enhancement in the anterior circulation excluding the intrapetrous ICAs (OR, 4.097; 95% CI, 1.483–11.319). Conclusions: Although the arterial wall enhancement on the Gd-3DBB probably reflects normal aging, the enhancement in the anterior circulation might be related to brain infarctions. On the other hand, the intrapetrous ICA enhancement is considered a nonspecific finding and should not be mistaken for arterial pathologies such as atherosclerosis or arteritis.

Regulation of abiotic and biotic stress responses by plant hormones

DEFF Research Database (Denmark)

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

2016-01-01

Plant hormones (phytohormones) are signal molecules produced within the plant, and occur in very low concentrations. In the present chapter, the current knowledge on the regulation of biotic and biotic stress responses by plant hormones is summarized with special focus on the novel insights...... into the complex hormonal crosstalk of classical growth stimulating plant hormones within the naturally occurring biotic and abiotic multistress environment of higher plants. The MAPK- and phytohormone-cascades which comprise a multitude of single molecules on different signalling levels, as well as interactions...

Arbuscular Mycorrhizal Fungal 14-3-3 Proteins Are Involved in Arbuscule Formation and Responses to Abiotic Stresses During AM Symbiosis.

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Sun, Zhongfeng; Song, Jiabin; Xin, Xi'an; Xie, Xianan; Zhao, Bin

2018-01-01

Arbuscular mycorrhizal (AM) fungi are soil-borne fungi belonging to the ancient phylum Glomeromycota and are important symbionts of the arbuscular mycorrhiza, enhancing plant nutrient acquisition and resistance to various abiotic stresses. In contrast to their significant physiological implications, the molecular basis involved is poorly understood, largely due to their obligate biotrophism and complicated genetics. Here, we identify and characterize three genes termed Fm201 , Ri14-3-3 and RiBMH2 that encode 14-3-3-like proteins in the AM fungi Funneliformis mosseae and Rhizophagus irregularis , respectively. The transcriptional levels of Fm201 , Ri14-3-3 and RiBMH2 are strongly induced in the pre-symbiotic and symbiotic phases, including germinating spores, intraradical hyphae- and arbuscules-enriched roots. To functionally characterize the Fm201 , Ri14-3-3 and RiBMH2 genes, we took advantage of a yeast heterologous system owing to the lack of AM fungal transformation systems. Our data suggest that all three genes can restore the lethal Saccharomyces cerevisiae bmh1 bmh2 double mutant on galactose-containing media. Importantly, yeast one-hybrid analysis suggests that the transcription factor RiMsn2 is able to recognize the STRE (CCCCT/AGGGG) element present in the promoter region of Fm201 gene. More importantly, Host-Induced Gene Silencing of both Ri14-3-3 and RiBMH2 in Rhizophagus irregularis impairs the arbuscule formation in AM symbiosis and inhibits the expression of symbiotic PT4 and MST2 genes from plant and fungal partners, respectively. We further subjected the AM fungus- Medicago truncatula association system to drought or salinity stress. Accordingly, the expression profiles in both mycorrhizal roots and extraradical hyphae reveal that these three 14-3-3-like genes are involved in response to drought or salinity stress. Collectively, our results provide new insights into molecular functions of the AM fungal 14-3-3 proteins in abiotic stress responses and

Abscisic Acid and Gibberellins Antagonistically Mediate Plant Development and Abiotic Stress Responses

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Kai Shu

2018-03-01

Full Text Available Phytohormones regulate numerous important biological processes in plant development and biotic/abiotic stress response cascades. More than 50 and 100 years have passed since the initial discoveries of the phytohormones abscisic acid (ABA and gibberellins (GA, respectively. Over the past several decades, numerous elegant studies have demonstrated that ABA and GA antagonistically regulate many plant developmental processes, including seed maturation, seed dormancy and germination, root initiation, hypocotyl and stem elongation, and floral transition. Furthermore, as a well-established stress hormone, ABA plays a key role in plant responses to abiotic stresses, such as drought, flooding, salinity and low temperature. Interestingly, recent evidence revealed that GA are also involved in plant response to adverse environmental conditions. Consequently, the complex crosstalk networks between ABA and GA, mediated by diverse key regulators, have been extensively investigated and documented. In this updated mini-review, we summarize the most recent advances in our understanding of the antagonistically regulatory roles of ABA and GA in different stages of plant development and in various plant–environment interactions, focusing on the crosstalk between ABA and GA at the levels of phytohormone metabolism and signal transduction.

Recent advances in utilizing transcription factors to improve plant abiotic stress tolerance by transgenic technology

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Hongyan eWang

2016-02-01

Full Text Available Agricultural production and quality are adversely affected by various abiotic stresses worldwide and this will be exacerbated by the deterioration of global climate. To feed a growing world population, it is very urgent to breed stress-tolerant crops with higher yields and improved qualities against multiple environmental stresses. Since conventional breeding approaches had marginal success due to the complexity of stress tolerance traits, the transgenic approach is now being popularly used to breed stress-tolerant crops. So identifying and characterizing the the critical genes involved in plant stress responses is an essential prerequisite for engineering stress-tolerant crops. Far beyond the manipulation of single functional gene, engineering certain regulatory genes has emerged as an effective strategy now for controlling the expression of many stress-responsive genes. Transcription factors (TFs are good candidates for genetic engineering to breed stress-tolerant crop because of their role as master regulators of many stress-responsive genes. Many TFs belonging to families AP2/EREBP, MYB, WRKY, NAC, bZIP have been found to be involved in various abiotic stresses and some TF genes have also been engineered to improve stress tolerance in model and crop plants. In this review, we take five large families of TFs as examples and review the recent progress of TFs involved in plant abiotic stress responses and their potential utilization to improve multiple stress tolerance of crops in the field conditions.

Potato crop growth as influenced by potato cyst nematodes (Globodera pallida) and abiotic factors

NARCIS (Netherlands)

Ruijter, de F.

1998-01-01

The objective of the research described in this thesis was to determine the major mechanisms by which potato cyst nematodes reduce potato crop growth and to explain interactions known to occur with cultivar and abiotic factors. Understanding of these interactions may lead to strategies that

Enhanced Indirect Photochemical Transformation of Histidine and Histamine through Association with Chromophoric Dissolved Organic Matter.

Science.gov (United States)

Chu, Chiheng; Lundeen, Rachel A; Remucal, Christina K; Sander, Michael; McNeill, Kristopher

2015-05-05

Photochemical transformations greatly affect the stability and fate of amino acids (AAs) in sunlit aquatic ecosystems. Whereas the direct phototransformation of dissolved AAs is well investigated, their indirect photolysis in the presence of chromophoric dissolved organic matter (CDOM) is poorly understood. In aquatic systems, CDOM may act both as sorbent for AAs and as photosensitizer, creating microenvironments with high concentrations of photochemically produced reactive intermediates, such as singlet oxygen (1O2). This study provides a systematic investigation of the indirect photochemical transformation of histidine (His) and histamine by 1O2 in solutions containing CDOM as a function of solution pH. Both His and histamine showed pH-dependent enhanced phototransformation in the CDOM systems as compared to systems in which model, low-molecular-weight 1O2 sensitizers were used. Enhanced reactivity resulted from sorption of His and histamine to CDOM and thus exposure to elevated 1O2 concentrations in the CDOM microenvironment. The extent of reactivity enhancement depended on solution pH via its effects on the protonation state of His, histamine, and CDOM. Sorption-enhanced reactivity was independently supported by depressed rate enhancements in the presence of a cosorbate that competitively displaced His and histamine from CDOM. Incorporating sorption and photochemical transformation processes into a reaction rate prediction model improved the description of the abiotic photochemical transformation rates of His in the presence of CDOM.

Abiotic Hydrolysis of Fluorotelomer-Based Polymers as a Source of Perfluorocarboxylates at the Global Scale

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Fluorotelomer-based polymers (FTPs) are the main product of the fluorotelomer industry. For nearly 10 years, whether FTPs degrade to form perfluorooctanoate (PFOA) and perfluorocarboxylate (PFCA) homologues has been vigorously contested. Here we show that circum-neutral abiotic h...

A Model of Continental Growth and Mantle Degassing Comparing Biotic and Abiotic Worlds

Science.gov (United States)

Höning, D.; Hansen-Goos, H.; Spohn, T.

2012-12-01

While examples for interaction of the biosphere with the atmosphere can be easily cited (e.g., production and consumption of O2), interaction between the biosphere and the solid planet and its interior is much less established. It has been argued (e.g., Rosing et al. 2006; Sleep et al, 2012) that the formation of continents could be a consequence of bioactivity harvesting solar energy through photosynthesis to help build the continents and that the mantle should carry a chemical biosignature. We present an interaction model that includes mantle convection, mantle water vapor degassing at mid-oceanic ridges and regassing through subduction zones, continental crust formation and erosion and water storage and transport in a porous oceanic crust that includes hydrous mineral phases. The mantle viscosity in this model depends on the water concentration in the mantle. We use boundary layer theory of mantle convection to parameterize the mantle convection flow rate and assume that the plate speed equals the mantle flow rate. The biosphere enters the calculation through the assumption that the continental erosion rate is enhanced by a factor of several through bioactivity and through an assumed reduction of the kinetic barrier to diagenetic and metamorphic reactions (e.g., Kim et al. 2004) in the sedimentary basins in subduction zones that would lead to increased water storage capacities. We further include a stochastic model of continent-to-continent interactions that limits the effective total length of subduction zones. We use present day parameters of the Earth and explore a phase plane spanned by the percentage of surface coverage of the Earth by continents and the total water content of the mantle. We vary the ratio of the erosion rate in a postulated abiotic Earth to the present Earth, as well as the activation barrier to diagenetic and metamorphic reactions that affect the water storage capacity of the subducting crust. We find stable and unstable fixed points in

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

Science.gov (United States)

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

2016-01-01

To face future challenges in crop production dictated by global climate changes, breeders and plant researchers collaborate to develop productive crops that are able to withstand a wide range of biotic and abiotic stresses. However, crop selection is often focused on shoot performance alone, as observation of root properties is more complex and asks for artificial and extensive phenotyping platforms. In addition, most root research focuses on development, while a direct link to the functionality of plasticity in root development for tolerance is often lacking. In this paper we review the currently known root system architecture (RSA) responses in Arabidopsis and a number of crop species to a range of abiotic stresses, including nutrient limitation, drought, salinity, flooding, and extreme temperatures. For each of these stresses, the key molecular and cellular mechanisms underlying the RSA response are highlighted. To explore the relevance for crop selection, we especially review and discuss studies linking root architectural responses to stress tolerance. This will provide a first step toward understanding the relevance of adaptive root development for a plant’s response to its environment. We suggest that functional evidence on the role of root plasticity will support breeders in their efforts to include root properties in their current selection pipeline for abiotic stress tolerance, aimed to improve the robustness of crops. PMID:27630659

The net effect of abiotic conditions and biotic interactions in a semi-arid ecosystem NE Spain: implications for the management and restoration.

Science.gov (United States)

Pueyo, Yolanda; Arroyo, Antonio I.; Saiz, Hugo; Alados, Concepción L.

2014-05-01

Degradation in arid and semiarid lands can be irreversible without human intervention, due to a positive plant-soil feedback where the loss of vegetation cover leads to soil degradation, which in turn hampers plant establishment. Human intervention in restoration actions usually involves the amendment of the degraded abiotic conditions, revegetation of bare areas, or both. However, abiotic amelioration is often expensive and too intrusive, and revegetation is not successful in many cases. Biotic interactions between plants, and more specifically facilitation by a "nurse" plant, have been proposed as a new via to take profit of improved abiotic conditions without intervention, and to increase the success rate of revegetation actions. But "nurse" plants can also interfere with others (i.e. by competition for resources or the release of allelopathic compounds), and the net balance between facilitation and interference could depend on plant types involved. We present recent observational and experimental studies performed in the semiarid ecosystems of the Middle Ebro Valley (NE Spain) about the role of abiotic conditions and biotic interactions in the productivity, dynamics and diversity of plant communities under different stress conditions (aridity and grazing). We found that all plant types studied (shrubs and perennial grasses) improved abiotic conditions (soil temperature and water availability for plants) with respect to open areas. However, only some shrubs (mainly Salsola vermiculata) had a positive net balance in the biotic interactions between plants, while other shrubs (Artemisia herba-alba) and perennial grasses (Lygeum spartum) showed interference with other plants. Moreover, the net balance between facilitation and interference among plants in the community shifted from competitive to neutral or from neutral to facilitative with increasing aridity. Grazing status did not strongly change the net biotic interactions between plants. Our results suggest that

An MFS Transporter-Like ORF from MDR Acinetobacter baumannii AIIMS 7 Is Associated with Adherence and Biofilm Formation on Biotic/Abiotic Surface

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Praveen K. Sahu

2012-01-01

Full Text Available A major facilitator superfamily (MFS transporter-like open reading frame (ORF of 453 bp was identified in a pathogenic strain Acinetobacter baumannii AIIMS 7, and its association with adherence and biofilm formation was investigated. Reverse transcription PCR (RT-PCR showed differential expression in surface-attached biofilm cells than nonadherent cells. In vitro translation showed synthesis of a ∼17 kDa protein, further confirmed by cloning and heterologous expression in E. coli DH5. Up to 2.1-, 3.1-, and 4.1- fold biofilm augmentation was observed on abiotic (polystyrene and biotic (S. cerevisiae/HeLa surface, respectively. Scanning electron microscopy (SEM and gfp-tagged fluorescence microscopy revealed increased adherence to abiotic (glass and biotic (S. cerevisiae surface. Extracellular DNA(eDNA was found significantly during active growth; due to probable involvement of the protein in DNA export, strong sequence homology with MFS transporter proteins, and presence of transmembrane helices. In summary, our findings show that the putative MFS transporter-like ORF (pmt is associated with adherence, biofilm formation, and probable eDNA release in A. baumannii AIIMS 7.

Predicting macropores in space and time by earthworms and abiotic controls

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Hohenbrink, Tobias Ludwig; Schneider, Anne-Kathrin; Zangerlé, Anne; Reck, Arne; Schröder, Boris; van Schaik, Loes

2017-04-01

Macropore flow increases infiltration and solute leaching. The macropore density and connectivity, and thereby the hydrological effectiveness, vary in space and time due to earthworms' burrowing activity and their ability to refill their burrows in order to survive drought periods. The aim of our study was to predict the spatiotemporal variability of macropore distributions by a set of potentially controlling abiotic variables and abundances of different earthworm species. We measured earthworm abundances and effective macropore distributions using tracer rainfall infiltration experiments in six measurement campaigns during one year at six field sites in Luxembourg. Hydrologically effective macropores were counted in three soil depths (3, 10, 30 cm) and distinguished into three diameter classes (6 mm). Earthworms were sampled and determined to species-level. In a generalized linear modelling framework, we related macropores to potential spatial and temporal controlling factors. Earthworm species such as Lumbricus terrestris and Aporrectodea longa, local abiotic site conditions (land use, TWI, slope), temporally varying weather conditions (temperature, humidity, precipitation) and soil moisture affected the number of effective macropores. Main controlling factors and explanatory power of the models (uncertainty and model performance) varied depending on the depth and diameter class of macropores. We present spatiotemporal predictions of macropore density by daily-resolved, one year time series of macropore numbers and maps of macropore distributions at specific dates in a small-scale catchment with 5 m resolution.

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

Kinetics of abiotic nitrous oxide production via oxidation of hydroxylamine by particulate metals in seawater

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Cavazos, A. R.; Taillefert, M.; Glass, J. B.

2016-12-01

The oceans are a significant of nitrous oxide (N2O) to the atmosphere. Current models of global oceanic N2­O flux focus on microbial N2O cycling and often ignore abiotic reactions, such as the thermodynamically favorable oxidation of the nitrification intermediate hydroxylamine (NH2OH) by Mn(IV) or Fe(III). At circumneutral pH, NH2OH oxidation is more thermodynamically favorable via Mn(IV) than Fe(III) reduction. We characterized the kinetics of NH2OH oxidation in synthetic ocean water at pH 5.1-8.8 using microsensor electrodes to measure real-time N2O production. N2O production rates and yield were greater when NH2OH was oxidized by Mn(IV) than Fe(III). Accordingly, the reduction of Mn(IV) was first order with respect to NH2OH whereas the reduction of Fe(III) was zero order with respect to NH2OH. Interestingly, the order of the reaction with respect to Mn(IV) appears to be negative whereas the reaction is second order with respect to Fe(III). The inverse order with respect to Mn(IV) may be due to the aggregation of particles in seawater, which decreases their surface area and changes their reactivity. Finally, the reaction is first order with respect to protons with Fe(III) as the oxidant but zero order with Mn(IV). The stronger effect of the pH on the reaction with Fe(III) as the oxidant compared to Mn(IV) reflects the stoichiometry of these two reactions, as each mole of N2O produced by Fe(III) reduction consumes eight protons while each mole of N2O produced with Mn(IV) as the oxidant requires only four protons. Our data show that abiotic NH2OH oxidation by Mn(IV) or Fe(III) particles may represent a significant source of N2O in seawater. These findings suggest that abiotic N2O production in marine waters may be significant in areas of the oceans where particulate metals originating from aerosols, dust, or rivers may react with NH2OH released from ammonia-oxidizing microorganisms.

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

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

2016-01-01

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

Abiotic synthesis of porphyrins and other oligopyrroles on the early Earth and Earth-like planets

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Fox, S.; Strasdeit, H.

2013-09-01

It is generally accepted that abiotically formed amino acids existed on Earth in the late Hadean and early Archean (four billion years ago). They were mainly dissolved in a salty primordial ocean. At that time, volcanic islands were much more abundant than today. It is therefore reasonable to assume that, at hot volcanic coasts, amino acids could have been thermally transformed into other organic molecules. Based on this scenario, we conducted laboratory experiments that simulated the interaction between amino acid-containing sea water and hot lava. In these experiments, a large number of different volatile products were formed, among them pyrroles. It was also possible to obtain porphyrins and other oligopyrroles from pyrroles under simulated conditions of primordial volcanic islands. All experiments were conducted under plausible prebiotic conditions. Our results reveal an abiotic pathway to possible precursors of oligopyrrole-type biomolecules, such as heme and chlorophylls.

Review of Microbial Responses to Abiotic Environmental Factors in the Context of the Proposed Yucca Mountain Repository

International Nuclear Information System (INIS)

Meike, A.; Stroes-Gascoyne, S.

2000-01-01

A workshop on Microbial Activities at Yucca Mountain (May 1995, Lafayette, CA) was held with the intention to compile information on all pertinent aspects of microbial activity for application to a potential repository at Yucca Mountain. The findings of this workshop set off a number of efforts intended to eventually incorporate the impacts of microbial behavior into performance assessment models. One effort was to expand an existing modeling approach to include the distinctive characteristics of a repository at Yucca Mountain (e.g., unsaturated conditions and a significant thermal load). At the same time, a number of experimental studies were initiated as well as a compilation of relevant literature to more thoroughly study the physical, chemical and biological parameters that would affect microbial activity under Yucca Mountain-like conditions. This literature search (completed in 1996) is the subject of the present document. The collected literature can be divided into four categories: (1) abiotic factors, (2) community dynamics and in-situ considerations, (3) nutrient considerations and (4) transport of radionuclides. The complete bibliography represents a considerable resource, but is too large to be discussed in one document. Therefore, the present report focuses on the first category, abiotic factors, and a discussion of these factors in order to facilitate the development of a model for Yucca Mountain

Simultaneous influence of indigenous microorganism along with abiotic factors controlling arsenic mobilization in Brahmaputra floodplain, India

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Sathe, Sandip S.; Mahanta, Chandan; Mishra, Pushpanjali

2018-06-01

In the dynamic cycling of oxic and anoxic aqueous alluvial aquifer environments, varying Arsenic (As) concentrations are controlled by both abiotic and biotic factors. Studies have shown a significant form of toxic As (III) being released through the reductive dissolution of iron-oxy/hydroxide minerals and microbial reduction mechanisms, which leads to a serious health concern. The present study was performed in order to assess the abiotic and biotic factors influencing As release into the alluvial aquifer groundwater in Brahmaputra floodplain, India. The groundwater chemistry, characterization of the sediments, isolation, identification and characterization of prominent As releasing indigenous bacterium were conducted. The measured solid and liquid phases of total As concentration were ranged between 0.02 and 17.2 mg kg-1 and 8 to 353 μg L-1, respectively. The morphology and mineralogy showed the presence of detrital and authigenic mineral assemblages whereas primary and secondary As bearing Realgar and Claudetite minerals were identified, respectively. Furthermore, significant non-labile As fraction was found associated with the amorphous oxides of Fe, Mn and Al. The observed groundwater chemistry and sediment color, deduced a sub-oxic reducing aquifer conditions in As-contaminated regions. In addition, 16S rDNA sequencing results of the isolated bacterium showed the prominent Pseudomonas aeruginosa responsible for the mobilization of As, reducing condition, biomineralization and causing grey color to the sediments at the shallower and deeper aquifers in the study area. These findings suggest that microbial metabolic activities are equally responsible in iron-oxy/hydroxide reductive dissolution, controlling As mobilization in dynamic fluvial flood plains.

Minerals Masquerading As Enzymes: Abiotic Oxidation Of Soil Organic Matter In An Iron-Rich Humid Tropical Forest Soil

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Hall, S. J.; Silver, W. L.

2010-12-01

). Tyrosinase generated a red compound (dopachrome) that is the target analyte of the traditional L-DOPA oxidative enzyme assay, whereas our soil slurries generated purple melanin-like compounds that were likely generated by more extensive oxidation. To investigate the importance of Fe(II) for L-DOPA oxidation, we added realistic concentrations of Fe(II) (equivalent to 10 - 500 μg Fe g-1 soil) to an L-DOPA buffer solution under oxic conditions, and found rates of L-DOPA oxidation comparable to those from soil slurries. Molecular oxygen and Fe(II) are known to generate strong oxidants via Fenton reactions. We decreased L-DOPA oxidation rates in soil slurries by adding catalase and superoxide-dismutase enzymes to scavenge reactive oxygen species, suggesting that a free-radical mechanism contributed to L-DOPA oxidation. We obtained similar results using another humic model compound, tetramethylbenzidine (TMB). Although abiotic oxidative reactions involving iron have been employed to degrade anthropogenic organic contaminants, this study is among the first to demonstrate their potential importance for oxidizing organic matter in natural ecosystems. In soils rich in Fe(II), abiotic reactions could complement, or even obviate, the role of microbial oxidative enzymes in degrading recalcitrant organic compounds.

ThDof1.4 and ThZFP1 constitute a transcriptional regulatory cascade involved in salt or osmotic stress in Tamarix hispida.

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Zang, Dandan; Wang, Lina; Zhang, Yiming; Zhao, Huimin; Wang, Yucheng

2017-07-01

Identification of the upstream regulators of a gene is important to characterize the transcriptional pathway and the function of the gene. Previously, we found that a zinc finger protein (ThZFP1) is involved in abiotic stress tolerance of Tamarix hispida. In the present study, we further investigated the transcriptional pathway of ThZFP1. Dof motifs are abundant in the ThZFP1 promoter; therefore, we used them to screen for transcriptional regulators of ThZFP1. A Dof protein, ThDof1.4, binds to the Dof motif specifically, and was hypothesized as the upstream regulator of ThZFP1. Further study showed that overexpression of ThDof1.4 in T. hispida activated the expression of GUS controlled by the ThZFP1 promoter. In T. hispida, transient overexpression of ThDof1.4 increased the transcripts of ThZFP1; conversely, transient RNAi-silencing of ThDof1.4 reduced the expression of ThZFP1. Chromatin immunoprecipitation indicated that ThDof1.4 binds to the ThZFP1 promoter. Additionally, ThDof1.4 and ThZFP1 share similar expression patterns in response to salt or drought stress. Furthermore, like ThZFP1, ThDof1.4 could increase the proline level and enhance ROS scavenging capability to improve salt and osmotic stress tolerance. Together, these results suggested that ThDof1.4 and ThZFP1 form a transcriptional regulatory cascade involved in abiotic stress resistance in T. hispida.

Comparative physiological, metabolomic, and transcriptomic analyses reveal mechanisms of improved abiotic stress resistance in bermudagrass [Cynodon dactylon (L). Pers.] by exogenous melatonin

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Shi, Haitao; Jiang, Chuan; Ye, Tiantian; Tan, Dun-xian; Reiter, Russel J.; Zhang, Heng; Liu, Renyi; Chan, Zhulong

2015-01-01

Melatonin (N-acetyl-5-methoxytryptamine), a well-known animal hormone, is also involved in plant development and abiotic stress responses. In this study, it is shown that exogenous application of melatonin conferred improved salt, drought, and cold stress resistances in bermudagrass. Moreover, exogenous melatonin treatment alleviated reactive oxygen species (ROS) burst and cell damage induced by abiotic stress; this involved activation of several antioxidants. Additionally, melatonin-pre-treated plants exhibited higher concentrations of 54 metabolites, including amino acids, organic acids, sugars, and sugar alcohols, than non-treated plants under abiotic stress conditions. Genome-wide transcriptomic profiling identified 3933 transcripts (2361 up-regulated and 1572 down-regulated) that were differentially expressed in melatonin-treated plants versus controls. Pathway and gene ontology (GO) term enrichment analyses revealed that genes involved in nitrogen metabolism, major carbohydrate metabolism, tricarboxylic acid (TCA)/org transformation, transport, hormone metabolism, metal handling, redox, and secondary metabolism were over-represented after melatonin pre-treatment. Taken together, this study provides the first evidence of the protective roles of exogenous melatonin in the bermudagrass response to abiotic stresses, partially via activation of antioxidants and modulation of metabolic homeostasis. Notably, metabolic and transcriptomic analyses showed that the underlying mechanisms of melatonin could involve major reorientation of photorespiratory and carbohydrate and nitrogen metabolism. PMID:25225478

Enhanced oxidative stress in the jasmonic acid-deficient tomato mutant def-1 exposed to NaCl stress.

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Abouelsaad, Ibrahim; Renault, Sylvie

2018-04-21

Jasmonic acid (JA) has been mostly studied in responses to biotic stresses, such as herbivore attack and pathogenic infection. More recently, the involvement of JA in abiotic stresses including salinity was highlighted; yet, its role in salt stress remained unclear. In the current study, we compared the physiological and biochemical responses of wild-type (WT) tomato (Solanum lycopersicum) cv Castlemart and its JA-deficient mutant defenseless-1 (def-1) under salt stress to investigate the role of JA. Plant growth, photosynthetic pigment content, ion accumulation, oxidative stress-related parameters, proline accumulation and total phenolic compounds, in addition to both enzymatic and non-enzymatic antioxidant activities, were measured in both genotypes after 14 days of 100 mM NaCl treatment. Although we observed in both genotypes similar growth pattern and sodium, calcium and potassium levels in leaves under salt stress, def-1 plants exhibited a more pronounced decrease of nitrogen content in both leaves and roots and a slightly higher level of sodium in roots compared to WT plants. In addition, def-1 plants exposed to salt stress showed reactive oxygen species (ROS)-associated injury phenotypes. These oxidative stress symptoms in def-1 were associated with lower activity of both enzymatic antioxidants and non-enzymatic antioxidants. Furthermore, the levels of the non-enzymatic ROS scavengers proline and total phenolic compounds increased in both genotypes exposed to salt stress, with a higher amount of proline in the WT plants. Overall the results of this study suggest that endogenous JA mainly enhanced tomato salt tolerance by maintaining ROS homeostasis. Copyright © 2018 Elsevier GmbH. 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...

Genome-wide expression analysis of rice ABC transporter family across spatio-temporal samples and in response to abiotic stresses.

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Nguyen, Van Ngoc Tuyet; Moon, Sunok; Jung, Ki-Hong

2014-09-01

Although the super family of ATP-binding cassette (ABC) proteins plays key roles in the physiology and development of plants, the functions of members of this interesting family mostly remain to be clarified, especially in crop plants. Thus, systematic analysis of this family in rice (Oryza sativa), a major model crop plant, will be helpful in the design of effective strategies for functional analysis. Phylogenomic analysis that integrates anatomy and stress meta-profiling data based on a large collection of rice Affymetrix array data into the phylogenic context provides useful clues into the functions for each of the ABC transporter family members in rice. Using anatomy data, we identified 17 root-preferred and 16-shoot preferred genes at the vegetative stage, and 3 pollen, 2 embryo, 2 ovary, 2 endosperm, and 1 anther-preferred gene at the reproductive stage. The stress data revealed significant up-regulation or down-regulation of 47 genes under heavy metal treatment, 16 genes under nutrient deficient conditions, and 51 genes under abiotic stress conditions. Of these, we confirmed the differential expression patterns of 14 genes in root samples exposed to drought stress using quantitative real-time PCR. Network analysis using RiceNet suggests a functional gene network involving nine rice ABC transporters that are differentially regulated by drought stress in root, further enhancing the prediction of biological function. Our analysis provides a molecular basis for the study of diverse biological phenomena mediated by the ABC family in rice and will contribute to the enhancement of crop yield and stress tolerance. Copyright © 2014 Elsevier GmbH. All rights reserved.

Reference Gene Selection for qRT-PCR Normalization Analysis in kenaf (Hibiscus cannabinus L. under Abiotic Stress and Hormonal Stimuli

Directory of Open Access Journals (Sweden)

Xiaoping Niu

2017-05-01

Full Text Available Kenaf (Hibiscus cannabinus L., an environmental friendly and economic fiber crop, has a certain tolerance to abiotic stresses. Identification of reliable reference genes for transcript normalization of stress responsive genes expression by quantitative real-time PCR (qRT-PCR is important for exploring the molecular mechanisms of plants response to abiotic stresses. In this study, nine candidate reference genes were cloned, and their expression stabilities were assessed in 132 abiotic stress and hormonal stimuli samples of kenaf using geNorm, NormFinder, and BestKeeper algorithms. Results revealed that HcPP2A (Protein phosphatase 2A and HcACT7 (Actin 7 were the optimum reference genes across all samples; HcUBC (Ubiquitin-conjugating enzyme like protein was the worst reference gene for transcript normalization. The reliability of the selected reference genes was further confirmed by evaluating the expression profile of HcWRKY28 gene at different stress durations. This work will benefit future studies on discovery of stress-tolerance genes and stress-signaling pathways in this important fiber crop.

Physiological and transcriptomic responses in the seed coat of field-grown soybean (Glycine max L. Merr.) to abiotic stress.

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Leisner, Courtney P; Yendrek, Craig R; Ainsworth, Elizabeth A

2017-12-12

Understanding how intensification of abiotic stress due to global climate change affects crop yields is important for continued agricultural productivity. Coupling genomic technologies with physiological crop responses in a dynamic field environment is an effective approach to dissect the mechanisms underpinning crop responses to abiotic stress. Soybean (Glycine max L. Merr. cv. Pioneer 93B15) was grown in natural production environments with projected changes to environmental conditions predicted for the end of the century, including decreased precipitation, increased tropospheric ozone concentrations ([O 3 ]), or increased temperature. All three environmental stresses significantly decreased leaf-level photosynthesis and stomatal conductance, leading to significant losses in seed yield. This was driven by a significant decrease in the number of pods per node for all abiotic stress treatments. To understand the underlying transcriptomic response involved in the yield response to environmental stress, RNA-Sequencing analysis was performed on the soybean seed coat, a tissue that plays an essential role in regulating carbon and nitrogen transport to developing seeds. Gene expression analysis revealed 49, 148 and 1,576 differentially expressed genes in the soybean seed coat in response to drought, elevated [O 3 ] and elevated temperature, respectively. Elevated [O 3 ] and drought did not elicit substantive transcriptional changes in the soybean seed coat. However, this may be due to the timing of sampling and does not preclude impacts of those stresses on different tissues or different stages in seed coat development. Expression of genes involved in DNA replication and metabolic processes were enriched in the seed coat under high temperate stress, suggesting that the timing of events that are important for cell division and proper seed development were altered in a stressful growth environment.

Intra-Specific Latitudinal Clines in Leaf Carbon, Nitrogen, and Phosphorus and their Underlying Abiotic Correlates in Ruellia Nudiflora.

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Abdala-Roberts, Luis; Covelo, Felisa; Parra-Tabla, Víctor; Terán, Jorge C Berny Mier Y; Mooney, Kailen A; Moreira, Xoaquín

2018-01-12

While plant intra-specific variation in the stoichiometry of nutrients and carbon is well documented, clines for such traits have been less studied, despite their potential to reveal the mechanisms underlying such variation. Here we analyze latitudinal variation in the concentration of leaf nitrogen (N), phosphorus (P), carbon (C) and their ratios across 30 populations of the perennial herb Ruellia nudiflora. In addition, we further determined whether climatic and soil variables underlie any such latitudinal clines in leaf traits. The sampled transect spanned 5° latitude (ca. 900 km) and exhibited a four-fold precipitation gradient and 2 °C variation in mean annual temperature. We found that leaf P concentration increased with precipitation towards lower latitudes, whereas N and C did not exhibit latitudinal clines. In addition, N:P and C:P decreased towards lower latitudes and latitudinal variation in the former was weakly associated with soil conditions (clay content and cation exchange capacity); C:N did not exhibit a latitudinal gradient. Overall, these results emphasize the importance of addressing and disentangling the simultaneous effects of abiotic factors associated with intra-specific clines in plant stoichiometric traits, and highlight the previously underappreciated influence of abiotic factors on plant nutrients operating under sharp abiotic gradients over smaller spatial scales.

Abiotic versus biotic iron mineral transformation studied by a miniaturized backscattering Mössbauer spectrometer (MIMOS II), X-ray diffraction and Raman spectroscopy

Science.gov (United States)

Markovski, C.; Byrne, J. M.; Lalla, E.; Lozano-Gorrín, A. D.; Klingelhöfer, G.; Rull, F.; Kappler, A.; Hoffmann, T.; Schröder, C.

2017-11-01

Searching for biomarkers or signatures of microbial transformations of minerals is a critical aspect for determining how life evolved on Earth, and whether or not life may have existed in other planets, including Mars. In order to solve such questions, several missions to Mars have sought to determine the geochemistry and mineralogy on the Martian surface. This research includes the two miniaturized Mössbauer spectrometers (MIMOS II) on board the Mars Exploration Rovers Spirit and Opportunity, which have detected a variety of iron minerals on Mars, including magnetite (Fe2+Fe3+2O4) and goethite (α-FeO(OH)). On Earth, both minerals can derive from microbiological activity (e.g. through dissimilatory iron reduction of ferrihydrite by Fe(III)-reducing bacteria). Here we used a lab based MIMOS II to characterize the mineral products of biogenic transformations of ferrihydrite to magnetite by the Fe(III)-reducing bacteria Geobacter sulfurreducens. In combination with Raman spectroscopy and X-ray diffraction (XRD), we observed the formation of magnetite, goethite and siderite. We compared the material produced by biogenic transformations to abiotic samples in order to distinguish abiotic and biotic iron minerals by techniques that are or will be available onboard Martian based laboratories. The results showed the possibility to distinguish the abiotic and biotic origin of the minerals. Mossbauer was able to distinguish the biotic/abiotic magnetite with the interpretation of the geological context (Fe content mineral assemblages and accompanying minerals) and the estimation of the particle size in a non-destructive way. The Raman was able to confirm the biotic/abiotic principal peaks of the magnetite, as well as the organic principal vibration bands attributed to the bacteria. Finally, the XRD confirmed the particle size and mineralogy.

Soybean DREB1/CBF-type transcription factors function in heat and drought as well as cold stress-responsive gene expression.

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Kidokoro, Satoshi; Watanabe, Keitaro; Ohori, Teppei; Moriwaki, Takashi; Maruyama, Kyonoshin; Mizoi, Junya; Myint Phyu Sin Htwe, Nang; Fujita, Yasunari; Sekita, Sachiko; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

2015-02-01

Soybean (Glycine max) is a globally important crop, and its growth and yield are severely reduced by abiotic stresses, such as drought, heat, and cold. The cis-acting element DRE (dehydration-responsive element)/CRT plays an important role in activating gene expression in response to these stresses. The Arabidopsis DREB1/CBF genes that encode DRE-binding proteins function as transcriptional activators in the cold stress responsive gene expression. In this study, we identified 14 DREB1-type transcription factors (GmDREB1s) from a soybean genome database. The expression of most GmDREB1 genes in soybean was strongly induced by a variety of abiotic stresses, such as cold, drought, high salt, and heat. The GmDREB1 proteins activated transcription via DREs (dehydration-responsive element) in Arabidopsis and soybean protoplasts. Transcriptome analyses using transgenic Arabidopsis plants overexpressing GmDREB1s indicated that many of the downstream genes are cold-inducible and overlap with those of Arabidopsis DREB1A. We then comprehensively analyzed the downstream genes of GmDREB1B;1, which is closely related to DREB1A, using a transient expression system in soybean protoplasts. The expression of numerous genes induced by various abiotic stresses were increased by overexpressing GmDREB1B;1 in soybean, and DREs were the most conserved element in the promoters of these genes. The downstream genes of GmDREB1B;1 included numerous soybean-specific stress-inducible genes that encode an ABA receptor family protein, GmPYL21, and translation-related genes, such as ribosomal proteins. We confirmed that GmDREB1B;1 directly activates GmPYL21 expression and enhances ABRE-mediated gene expression in an ABA-independent manner. These results suggest that GmDREB1 proteins activate the expression of numerous soybean-specific stress-responsive genes under diverse abiotic stress conditions. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

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

KAUST Repository

Zhang, Xiujuan; Yang, Guanyu; Shi, Rui; Han, Xiaomin; Qi, Liwang; Wang, Ruigang; Xiong, Liming; Li, Guojing

2013-01-01

The phytohormone abscisic acid (ABA) regulates seed germination, plant growth and development, and response to abiotic stresses such as drought and salt stresses. Receptor-like kinases are well known signaling components that mediate plant responses

Comparative physiological, metabolomic, and transcriptomic analyses reveal mechanisms of improved abiotic stress resistance in bermudagrass [Cynodon dactylon (L). Pers.] by exogenous melatonin.

Science.gov (United States)

Shi, Haitao; Jiang, Chuan; Ye, Tiantian; Tan, Dun-Xian; Reiter, Russel J; Zhang, Heng; Liu, Renyi; Chan, Zhulong

2015-02-01

Melatonin (N-acetyl-5-methoxytryptamine), a well-known animal hormone, is also involved in plant development and abiotic stress responses. In this study, it is shown that exogenous application of melatonin conferred improved salt, drought, and cold stress resistances in bermudagrass. Moreover, exogenous melatonin treatment alleviated reactive oxygen species (ROS) burst and cell damage induced by abiotic stress; this involved activation of several antioxidants. Additionally, melatonin-pre-treated plants exhibited higher concentrations of 54 metabolites, including amino acids, organic acids, sugars, and sugar alcohols, than non-treated plants under abiotic stress conditions. Genome-wide transcriptomic profiling identified 3933 transcripts (2361 up-regulated and 1572 down-regulated) that were differentially expressed in melatonin-treated plants versus controls. Pathway and gene ontology (GO) term enrichment analyses revealed that genes involved in nitrogen metabolism, major carbohydrate metabolism, tricarboxylic acid (TCA)/org transformation, transport, hormone metabolism, metal handling, redox, and secondary metabolism were over-represented after melatonin pre-treatment. Taken together, this study provides the first evidence of the protective roles of exogenous melatonin in the bermudagrass response to abiotic stresses, partially via activation of antioxidants and modulation of metabolic homeostasis. Notably, metabolic and transcriptomic analyses showed that the underlying mechanisms of melatonin could involve major reorientation of photorespiratory and carbohydrate and nitrogen metabolism. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

FATE OF PAH COMPOUNDS IN TWO SOIL TYPES: INFLUENCE OF VOLATILIZATION, ABIOTIC LOSS, AND BIOLOGICAL ACTIVITY

Science.gov (United States)

The fate of 14 polycyclic aromatic hydrocarbon (PAH) compounds was evaluated with regard to interphase transfer potential and mechanisms of treatment in soil under unsaturated conditions. Volatilization and abiotic and biotic fate of the PAHs were determined using two soils not p...

Arabidopsis AtbHLH112 regulates the expression of genes involved in abiotic stress tolerance by binding to their E-box and GCG-box motifs.

Science.gov (United States)

Liu, Yujia; Ji, Xiaoyu; Nie, Xianguang; Qu, Min; Zheng, Lei; Tan, Zilong; Zhao, Huimin; Huo, Lin; Liu, Shengnan; Zhang, Bing; Wang, Yucheng

2015-08-01

Plant basic helix-loop-helix (bHLH) transcription factors play essential roles in abiotic stress tolerance. However, most bHLHs have not been functionally characterized. Here, we characterized the functional role of a bHLH transcription factor from Arabidopsis, AtbHLH112, in response to abiotic stress. AtbHLH112 is a nuclear-localized protein, and its nuclear localization is induced by salt, drought and abscisic acid (ABA). In addition, AtbHLH112 serves as a transcriptional activator, with the activation domain located at its N-terminus. In addition to binding to the E-box motifs of stress-responsive genes, AtbHLH112 binds to a novel motif with the sequence 'GG[GT]CC[GT][GA][TA]C' (GCG-box). Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with salt and drought tolerance. AtbHLH112 mediates stress tolerance by increasing the expression of P5CS genes and reducing the expression of P5CDH and ProDH genes to increase proline levels. AtbHLH112 also increases the expression of POD and SOD genes to improve reactive oxygen species (ROS) scavenging ability. We present a model suggesting that AtbHLH112 is a transcriptional activator that regulates the expression of genes via binding to their GCG- or E-boxes to mediate physiological responses, including proline biosynthesis and ROS scavenging pathways, to enhance stress tolerance. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Surface physicochemistry and ionic strength affects eDNA's role in bacterial adhesion to abiotic surfaces

DEFF Research Database (Denmark)

Regina, Viduthalai R.; Lokanathan, Arcot R.; Modrzynski, Jakub Jan

2014-01-01

Extracellular DNA (eDNA) is an important structural component of biofilms formed by many bacteria, but few reports have focused on its role in initial cell adhesion. The aim of this study was to investigate the role of eDNA in bacterial adhesion to abiotic surfaces, and determine to which extent ...

Age-related Decline of Abiotic Stress Tolerance in Young Drosophila melanogaster Adults.

Science.gov (United States)

Colinet, Hervé; Chertemps, Thomas; Boulogne, Isabelle; Siaussat, David

2016-12-01

Stress tolerance generally declines with age as a result of functional senescence. Age-dependent alteration of stress tolerance can also occur in early adult life. In Drosophila melanogaster, evidence of such a decline in young adults has only been reported for thermotolerance. It is not known whether early adult life entails a general stress tolerance reduction and whether the response is peculiar to thermal traits. The present work was designed to investigate whether newly eclosed D melanogaster adults present a high tolerance to a range of biotic and abiotic insults. We found that tolerance to most of the abiotic stressors tested (desiccation, paraquat, hydrogen peroxide, deltamethrin, and malathion) was high in newly eclosed adults before dramatically declining over the next days of adult life. No clear age-related pattern was found for resistance to biotic stress (septic or fungal infection) and starvation. These results suggest that newly eclosed adults present a culminating level of tolerance to extrinsic stress which is likely unrelated to immune process. We argue that stress tolerance variation at very young age is likely a residual attribute from the previous life stage (ontogenetic carryover) or a feature related to the posteclosion development. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Oxygen and sulfur isotope systematics of sulfate produced during abiotic and bacterial oxidation of sphalerite and elemental sulfur

Science.gov (United States)

Balci, N.; Mayer, B.; Shanks, Wayne C.; Mandernack, K.W.

2012-01-01

Studies of metal sulfide oxidation in acid mine drainage (AMD) systems have primarily focused on pyrite oxidation, although acid soluble sulfides (e.g., ZnS) are predominantly responsible for the release of toxic metals. We conducted a series of biological and abiotic laboratory oxidation experiments with pure and Fe-bearing sphalerite (ZnS & Zn 0.88Fe 0.12S), respectively, in order to better understand the effects of sulfide mineralogy and associated biogeochemical controls of oxidation on the resultant ?? 34S and ?? 18O values of the sulfate produced. The minerals were incubated in the presence and absence of Acidithiobacillus ferrooxidans at an initial solution pH of 3 and with water of varying ?? 18O values to determine the relative contributions of H 2O-derived and O 2-derived oxygen in the newly formed sulfate. Experiments were conducted under aerobic and anaerobic conditions using O 2 and Fe(III) aq as the oxidants, respectively. Aerobic incubations with A. ferrooxidans, and S o as the sole energy source were also conducted. The ??34SSO4 values from both the biological and abiotic oxidation of ZnS and ZnS Fe by Fe(III) aq produced sulfur isotope fractionations (??34SSO4-ZnS) of up to -2.6???, suggesting the accumulation of sulfur intermediates during incomplete oxidation of the sulfide. No significant sulfur isotope fractionation was observed from any of the aerobic experiments. Negative sulfur isotope enrichment factors (??34SSO4-ZnS) in AMD systems could reflect anaerobic, rather than aerobic pathways of oxidation. During the biological and abiotic oxidation of ZnS and ZnS Fe by Fe(III) aq all of the sulfate oxygen was derived from water, with measured ?? 18OSO 4-H 2O values of 8.2??0.2??? and 7.5??0.1???, respectively. Also, during the aerobic oxidation of ZnS Fe and S o by A. ferrooxidans, all of the sulfate oxygen was derived from water with similar measured ?? 18OSO 4-H 2O values of 8.1??0.1??? and 8.3??0.3???, respectively. During biological oxidation

Roots withstanding their environment : Exploiting root system architecture responses to abiotic stress to improve crop tolerance

NARCIS (Netherlands)

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

2016-01-01

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

Dicty_cDB: Contig-U16287-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available zed ... 46 0.12 2 ( CK269023 ) EST715101 potato abiotic stress cDNA library Sola... 46 0.12 2 ( U54774 ) Nicotiana tabacu...a... 36 0.26 3 ( DV114899 ) CV03010A1H02.f1 CV03-normalized library Euphorbia... 36 0.26 3 ( BT013106 ) Lycopersicon esculentu...mate decarboxylase isozyme... 58 1e-06 2 ( CK273593 ) EST719671 potato abiotic stress cDNA library Sola... 5... from flowers,8... 62 7e-05 1 ( CV516768 ) 0048P0016Z_H01_SP6 Mimulus guttatus library 1 Mim... 62...e-04 1 ( CK278060 ) EST724138 potato abiotic stress cDNA library Sola... 60 3e-04 1 ( AP009552 ) Microcystis

Biotic and a-biotic Mn and Fe cycling in deep sediments across a gradient of sulfate reduction rates along the California margin

Science.gov (United States)

Schneider-Mor, A.; Steefel, C.; Maher, K.

2011-12-01

The coupling between the biological and a-biotic processes controlling trace metals in deep marine sediments are not well understood, although the fluxes of elements and trace metals across the sediment-water interface can be a major contribution to ocean water. Four marine sediment profiles (ODP leg 167 sites 1011, 1017, 1018 and 1020)were examined to evaluate and quantify the biotic and abiotic reaction networks and fluxes that occur in deep marine sediments. We compared biogeochemical processes across a gradient of sulfate reduction (SR) rates with the objective of studying the processes that control these rates and how they affect major elements as well as trace metal redistribution. The rates of sulfate reduction, methanogenesis and anaerobic methane oxidation (AMO) were constrained using a multicomponent reactive transport model (CrunchFlow). Constraints for the model include: sediment and pore water concentrations, as well as %CaCO3, %biogenic silica, wt% carbon and δ13C of total organic carbon (TOC), particulate organic matter (POC) and mineral associated carbon (MAC). The sites are distinguished by the depth of AMO: a shallow zone is observed at sites 1018 (9 to 19 meters composite depth (mcd)) and 1017 (19 to 30 mcd), while deeper zones occur at sites 1011 (56 to 76 mcd) and 1020 (101 to 116 mcd). Sulfate reduction rates at the shallow AMO sites are on the order 1x10-16 mol/L/yr, much faster than rates in the deeper zone sulfate reduction (1-3x10-17 mol/L/yr), as expected. The dissolved metal ion concentrations varied between the sites, with Fe (0.01-7 μM) and Mn (0.01-57 μM) concentrations highest at Site 1020 and lowest at site 1017. The highest Fe and Mn concentrations occurred at various depths, and were not directly correlated with the rates of sulfate reduction and the maximum alkalinity values. The main processes that control cycling of Fe are the production of sulfide from sulfate reduction and the distribution of Fe-oxides. The Mn distribution

Identification of single nucleotide polymorphisms (SNPs at candidate genes involved in abiotic stress in two Prosopis species of hybrids

Directory of Open Access Journals (Sweden)

Maria F. Pomponio

2014-12-01

Full Text Available Aim of the study: Identify and compare SNPs on candidate genes related to abiotic stress in Prosopis chilensis, Prosopis flexuosa and interspecific hybridsArea of the study: Chaco árido, Argentina. Material and Methods: Fragments from 6 candidate genes were sequenced in 60 genotypes. DNA polymorphisms were analyzed.Main Results: The analysis revealed that the hybrids had the highest rate of polymorphism, followed by P. flexuosa and P. chilensis, the values found are comparable to other forest tree species.Research highlights: This approach will help to study genetic diversity variation on natural populations for assessing the effects of environmental changes.Keywords: SNPs; abiotic stress; interspecific variation; molecular markers. 

Biotic, abiotic, and management controls on the net ecosystem CO2 exchange of European mountain grassland ecosystems

DEFF Research Database (Denmark)

Wohlfahrt, Georg; Anderson-Dunn, Margaret; Bahn, Michael

2008-01-01

The net ecosystem carbon dioxide (CO2) exchange (NEE) of nine European mountain grassland ecosystems was measured during 2002-2004 using the eddy covariance method. Overall, the availability of photosynthetically active radiation (PPFD) was the single most important abiotic influence factor for NEE....... Its role changed markedly during the course of the season, PPFD being a better predictor for NEE during periods favorable for CO2 uptake, which was spring and autumn for the sites characterized by summer droughts (southern sites) and (peak) summer for the Alpine and northern study sites. This general...... pattern was interrupted by grassland management practices, that is, mowing and grazing, when the variability in NEE explained by PPFD decreased in concert with the amount of aboveground biomass (BMag). Temperature was the abiotic influence factor that explained most of the variability in ecosystem...

Enhancements to ASHRAE Standard 90.1 Prototype Building Models

Energy Technology Data Exchange (ETDEWEB)

Goel, Supriya; Athalye, Rahul A.; Wang, Weimin; Zhang, Jian; Rosenberg, Michael I.; Xie, YuLong; Hart, Philip R.; Mendon, Vrushali V.

2014-04-16

This report focuses on enhancements to prototype building models used to determine the energy impact of various versions of ANSI/ASHRAE/IES Standard 90.1. Since the last publication of the prototype building models, PNNL has made numerous enhancements to the original prototype models compliant with the 2004, 2007, and 2010 editions of Standard 90.1. Those enhancements are described here and were made for several reasons: (1) to change or improve prototype design assumptions; (2) to improve the simulation accuracy; (3) to improve the simulation infrastructure; and (4) to add additional detail to the models needed to capture certain energy impacts from Standard 90.1 improvements. These enhancements impact simulated prototype energy use, and consequently impact the savings estimated from edition to edition of Standard 90.1.

The physicochemical process of bacterial attachment to abiotic surfaces: Challenges for mechanistic studies, predictability and the development of control strategies.

Science.gov (United States)

Wang, Yi; Lee, Sui Mae; Dykes, Gary

2015-01-01

Bacterial attachment to abiotic surfaces can be explained as a physicochemical process. Mechanisms of the process have been widely studied but are not yet well understood due to their complexity. Physicochemical processes can be influenced by various interactions and factors in attachment systems, including, but not limited to, hydrophobic interactions, electrostatic interactions and substratum surface roughness. Mechanistic models and control strategies for bacterial attachment to abiotic surfaces have been established based on the current understanding of the attachment process and the interactions involved. Due to a lack of process control and standardization in the methodologies used to study the mechanisms of bacterial attachment, however, various challenges are apparent in the development of models and control strategies. In this review, the physicochemical mechanisms, interactions and factors affecting the process of bacterial attachment to abiotic surfaces are described. Mechanistic models established based on these parameters are discussed in terms of their limitations. Currently employed methods to study these parameters and bacterial attachment are critically compared. The roles of these parameters in the development of control strategies for bacterial attachment are reviewed, and the challenges that arise in developing mechanistic models and control strategies are assessed.

The influence of abiotic factors present in the Rio de la Plata over the chromium genotoxicity

International Nuclear Information System (INIS)

Lopez, L.C.; Moretton, J.

1997-01-01

The alterations suffered by the well-known environmental genotoxic agent, Cr(V I), were studied. Cr(V I) salts were dissolved in water effluent river receptors waters such as from the Rio de la Plata. The influence of abiotic factors present in this kind of water was evaluated using the Rec. assay in Bacillus subtilis. The results detected a soluble fraction that potentiated Cr(V I) genotoxicity. This substance (or group of substances) is sensible to sterilization by heat and UV radiation, and its activity seems to decrease with particulate matter. Its genotoxicity was not affected by high concentrations of particulate matter in the Rio de la Plata water. In samples where chromium salts were added to raw river water, abiotic interference due to sterilization process occurred. A decrease in genotoxicity was found after filtration through inorganic filters (0.22 μ m) and an increase was noticed after exposure to UV radiation. (Author)

The Zinc-Finger Thylakoid-Membrane Protein FIP Is Involved With Abiotic Stress Response in Arabidopsis thaliana

Directory of Open Access Journals (Sweden)

Karina L. Lopes

2018-04-01

Full Text Available Many plant genes have their expression modulated by stress conditions. Here, we used Arabidopsis FtsH5 protease, which expression is regulated by light stress, as bait in a yeast two-hybrid screen to search for new proteins involved in the stress response. As a result, we found FIP (FtsH5 Interacting Protein, which possesses an amino proximal cleavable transit peptide, a hydrophobic membrane-anchoring region, and a carboxyl proximal C4-type zinc-finger domain. In vivo experiments using FIP fused to green fluorescent protein (GFP showed a plastid localization. This finding was corroborated by chloroplast import assays that showed FIP inserted in the thylakoid membrane. FIP expression was down-regulated in plants exposed to high light intensity, oxidative, salt, and osmotic stresses, whereas mutant plants expressing low levels of FIP were more tolerant to these abiotic stresses. Our data shows a new thylakoid-membrane protein involved with abiotic stress response in Arabidopsis thaliana.

Ectopic Expression of JcWRKY Confers Enhanced Resistance in Transgenic Tobacco Against Macrophomina phaseolina.

Science.gov (United States)

Agarwal, Parinita; Patel, Khantika; Agarwal, Pradeep K

2018-04-01

Plants possess an innate immune system comprising of a complex network of closely regulated defense responses involving differential gene expression mediated by transcription factors (TFs). The WRKYs comprise of an important plant-specific TF family, which is involved in regulation of biotic and abiotic defenses. The overexpression of JcWRKY resulted in improved resistance in transgenic tobacco against Macrophomina phaseolina. The production of reactive oxygen species (ROS) and its detoxification through antioxidative system in the transgenics facilitates defense against Macrophomina. The enhanced catalase activity on Macrophomina infection limits the spread of infection. The transcript expression of antioxidative enzymes gene (CAT and SOD) and salicylic acid (SA) biosynthetic gene ICS1 showed upregulation during Macrophomina infection and combinatorial stress. The enhanced transcript of pathogenesis-related genes PR-1 indicates the accumulation of SA during different stresses. The PR-2 and PR-5 highlight the activation of defense responses comprising of activation of hydrolytic cleavage of glucanases and thaumatin-like proteins causing disruption of fungal cells. The ROS homeostasis in coordination with signaling molecules regulate the defense responses and inhibit fungal growth.

26 CFR 1.43-4 - Qualified enhanced oil recovery costs.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 1 2010-04-01 2010-04-01 true Qualified enhanced oil recovery costs. 1.43-4... TAXES Credits Against Tax § 1.43-4 Qualified enhanced oil recovery costs. (a) Qualifying costs—(1) In... “qualified enhanced oil recovery costs” if the amounts are paid or incurred with respect to an asset which is...

Biotic conversion of sulphate to sulphide and abiotic conversion of sulphide to sulphur in a microbial fuel cell using cobalt oxide octahedrons as cathode catalyst.

Science.gov (United States)

Chatterjee, Pritha; Ghangrekar, M M; Rao, Surampalli; Kumar, Senthil

2017-05-01

Varying chemical oxygen demand (COD) and sulphate concentrations in substrate were used to determine reaction kinetics and mass balance of organic matter and sulphate transformation in a microbial fuel cell (MFC). MFC with anodic chamber volume of 1 L, fed with wastewater having COD of 500 mg/L and sulphate of 200 mg/L, could harvest power of 54.4 mW/m 2 , at a Coulombic efficiency of 14%, with respective COD and sulphate removals of 90 and 95%. Sulphide concentration, even up to 1500 mg/L, did not inhibit anodic biochemical reactions, due to instantaneous abiotic oxidation to sulphur, at high inlet sulphate. Experiments on abiotic oxidation of sulphide to sulphur revealed maximum oxidation taking place at an anodic potential of -200 mV. More than 99% sulphate removal could be achieved in a MFC with inlet COD/sulphate of 0.75, giving around 1.33 kg/m 3  day COD removal. Bioelectrochemical conversion of sulphate facilitating sulphur recovery in a MFC makes it an interesting pollution abatement technique.

Cyclophilin B enhances HIV-1 infection

Energy Technology Data Exchange (ETDEWEB)

DeBoer, Jason; Madson, Christian J. [Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE (United States); Belshan, Michael, E-mail: michaelbelshan@creighton.edu [Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE (United States); The Nebraska Center for Virology, University of Nebraska, Lincoln, NE (United States)

2016-02-15

Cyclophilin B (CypB) is a member of the immunophilin family and intracellular chaperone. It predominantly localizes to the ER, but also contains a nuclear localization signal and is secreted from cells. CypB has been shown to interact with the Gag protein of human immunodeficiency type 1 (HIV-1). Several proteomic and genetic studies identified it as a potential factor involved in HIV replication. Herein, we show that over-expression of CypB enhances HIV infection by increasing nuclear import of viral DNA. This enhancement was unaffected by cyclosporine treatment and requires the N-terminus of the protein. The N-terminus contains an ER leader sequence, putative nuclear localization signal, and is required for secretion. Deletion of the N-terminus resulted in mislocalization from the ER and suppression of HIV infection. Passive transfer experiments showed that secreted CypB did not impact HIV infection. Combined, these experiments show that intracellular CypB modulates a pathway of HIV nuclear import. - Highlights: • CypB has been identified in several proteomic studies of HIV-1 infection. • CypB expression is upregulated in activated and infected T-cells. • Over-expression of CypB enhances HIV nuclear import and infection. • The N-terminus of CypB is necessary for these effects.

Cyclophilin B enhances HIV-1 infection

International Nuclear Information System (INIS)

DeBoer, Jason; Madson, Christian J.; Belshan, Michael

2016-01-01

Cyclophilin B (CypB) is a member of the immunophilin family and intracellular chaperone. It predominantly localizes to the ER, but also contains a nuclear localization signal and is secreted from cells. CypB has been shown to interact with the Gag protein of human immunodeficiency type 1 (HIV-1). Several proteomic and genetic studies identified it as a potential factor involved in HIV replication. Herein, we show that over-expression of CypB enhances HIV infection by increasing nuclear import of viral DNA. This enhancement was unaffected by cyclosporine treatment and requires the N-terminus of the protein. The N-terminus contains an ER leader sequence, putative nuclear localization signal, and is required for secretion. Deletion of the N-terminus resulted in mislocalization from the ER and suppression of HIV infection. Passive transfer experiments showed that secreted CypB did not impact HIV infection. Combined, these experiments show that intracellular CypB modulates a pathway of HIV nuclear import. - Highlights: • CypB has been identified in several proteomic studies of HIV-1 infection. • CypB expression is upregulated in activated and infected T-cells. • Over-expression of CypB enhances HIV nuclear import and infection. • The N-terminus of CypB is necessary for these effects.

Anoxic conditions are beneficial for abiotic diclofenac removal from water with manganese oxide (MnO2)

NARCIS (Netherlands)

Liu, Wenbo; Sutton, Nora B.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.

2018-01-01

This is the first study examining pharmaceutical removal under anoxic conditions with MnO2. This study compares the abiotic removal of seven pharmaceuticals with reactive MnO2 particles in the presence of oxygen (oxic conditions) and in the absence of oxygen (anoxic conditions). Due to the novelty

The role of abiotic factors in ecological strategies of Gravettian hunter–gatherers within Moravia, Czech Republic

Czech Academy of Sciences Publication Activity Database

Lisá, Lenka; Škrdla, Petr; Havlín Nováková, D.; Bajer, A.; Čejchan, Petr; Nývltová Fišáková, Miriam; Lisý, Pavel

2013-01-01

Roč. 294, 29 April (2013), s. 71-81 ISSN 1040-6182 Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z80010507 Institutional support: RVO:67985831 ; RVO:68081758 Keywords : Gravettian * geoarchaeology * archaeology * abiotic factors Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 2.128, year: 2013

The SbMT-2 gene from a halophyte confers abiotic stress tolerance and modulates ROS scavenging in transgenic tobacco.

Directory of Open Access Journals (Sweden)

Amit Kumar Chaturvedi

Full Text Available Heavy metals are common pollutants of the coastal saline area and Salicornia brachiata an extreme halophyte is frequently exposed to various abiotic stresses including heavy metals. The SbMT-2 gene was cloned and transformed to tobacco for the functional validation. Transgenic tobacco lines (L2, L4, L6 and L13 showed significantly enhanced salt (NaCl, osmotic (PEG and metals (Zn++, Cu++ and Cd++ tolerance compared to WT plants. Transgenic lines did not show any morphological variation and had enhanced growth parameters viz. shoot length, root length, fresh weight and dry weight. High seed germination percentage, chlorophyll content, relative water content, electrolytic leakage and membrane stability index confirmed that transgenic lines performed better under salt (NaCl, osmotic (PEG and metals (Zn++, Cu++ and Cd++ stress conditions compared to WT plants. Proline, H2O2 and lipid peroxidation (MDA analyses suggested the role of SbMT-2 in cellular homeostasis and H2O2 detoxification. Furthermore in vivo localization of H2O2 and O2-; and elevated expression of key antioxidant enzyme encoding genes, SOD, POD and APX evident the possible role of SbMT-2 in ROS scavenging/detoxification mechanism. Transgenic lines showed accumulation of Cu++ and Cd++ in root while Zn++ in stem under stress condition. Under control (unstressed condition, Zn++ was accumulated more in root but accumulation of Zn++ in stem under stress condition suggested that SbMT-2 may involve in the selective translocation of Zn++ from root to stem. This observation was further supported by the up-regulation of zinc transporter encoding genes NtZIP1 and NtHMA-A under metal ion stress condition. The study suggested that SbMT-2 modulates ROS scavenging and is a potential candidate to be used for phytoremediation and imparting stress tolerance.

The SbMT-2 gene from a halophyte confers abiotic stress tolerance and modulates ROS scavenging in transgenic tobacco.

Science.gov (United States)

Chaturvedi, Amit Kumar; Patel, Manish Kumar; Mishra, Avinash; Tiwari, Vivekanand; Jha, Bhavanath

2014-01-01

Heavy metals are common pollutants of the coastal saline area and Salicornia brachiata an extreme halophyte is frequently exposed to various abiotic stresses including heavy metals. The SbMT-2 gene was cloned and transformed to tobacco for the functional validation. Transgenic tobacco lines (L2, L4, L6 and L13) showed significantly enhanced salt (NaCl), osmotic (PEG) and metals (Zn++, Cu++ and Cd++) tolerance compared to WT plants. Transgenic lines did not show any morphological variation and had enhanced growth parameters viz. shoot length, root length, fresh weight and dry weight. High seed germination percentage, chlorophyll content, relative water content, electrolytic leakage and membrane stability index confirmed that transgenic lines performed better under salt (NaCl), osmotic (PEG) and metals (Zn++, Cu++ and Cd++) stress conditions compared to WT plants. Proline, H2O2 and lipid peroxidation (MDA) analyses suggested the role of SbMT-2 in cellular homeostasis and H2O2 detoxification. Furthermore in vivo localization of H2O2 and O2-; and elevated expression of key antioxidant enzyme encoding genes, SOD, POD and APX evident the possible role of SbMT-2 in ROS scavenging/detoxification mechanism. Transgenic lines showed accumulation of Cu++ and Cd++ in root while Zn++ in stem under stress condition. Under control (unstressed) condition, Zn++ was accumulated more in root but accumulation of Zn++ in stem under stress condition suggested that SbMT-2 may involve in the selective translocation of Zn++ from root to stem. This observation was further supported by the up-regulation of zinc transporter encoding genes NtZIP1 and NtHMA-A under metal ion stress condition. The study suggested that SbMT-2 modulates ROS scavenging and is a potential candidate to be used for phytoremediation and imparting stress tolerance.

Soil respiration in the cold desert environment of the Colorado Plateau (USA): Abiotic regulators and thresholds

Science.gov (United States)

Fernandez, D.P.; Neff, J.C.; Belnap, J.; Reynolds, R.L.

2006-01-01

Decomposition is central to understanding ecosystem carbon exchange and nutrient-release processes. Unlike mesic ecosystems, which have been extensively studied, xeric landscapes have received little attention; as a result, abiotic soil-respiration regulatory processes are poorly understood in xeric environments. To provide a more complete and quantitative understanding about how abiotic factors influence soil respiration in xeric ecosystems, we conducted soil- respiration and decomposition-cloth measurements in the cold desert of southeast Utah. Our study evaluated when and to what extent soil texture, moisture, temperature, organic carbon, and nitrogen influence soil respiration and examined whether the inverse-texture hypothesis applies to decomposition. Within our study site, the effect of texture on moisture, as described by the inverse texture hypothesis, was evident, but its effect on decomposition was not. Our results show temperature and moisture to be the dominant abiotic controls of soil respiration. Specifically, temporal offsets in temperature and moisture conditions appear to have a strong control on soil respiration, with the highest fluxes occurring in spring when temperature and moisture were favorable. These temporal offsets resulted in decomposition rates that were controlled by soil moisture and temperature thresholds. The highest fluxes of CO2 occurred when soil temperature was between 10 and 16??C and volumetric soil moisture was greater than 10%. Decomposition-cloth results, which integrate decomposition processes across several months, support the soil-respiration results and further illustrate the seasonal patterns of high respiration rates during spring and low rates during summer and fall. Results from this study suggest that the parameters used to predict soil respiration in mesic ecosystems likely do not apply in cold-desert environments. ?? Springer 2006.

Exploring biotic vs. abiotic controls on syngenetic carbonate and clay mineral precipitation

Science.gov (United States)

Nascimento, Gabriela S.; McKenzie, Judith A.; Martinez Ruiz, Francisca; Bontognali, Tomaso R. R.; Vasconcelos, Crisogono

2016-04-01

A possible syngenetic relationship between carbonate and clay mineral precipitation has been reported for sedimentary rocks deposited in both lacustrine and marine sedimentary environments throughout the geological record. In particular, the mineral dolomite is often found associated with Mg-rich clays, such as stevensite. It is notable that this carbonate/clay association has been recorded in numerous samples taken from modern dolomite precipitating environments; for example, the Coorong lakes, South Australia, coastal sabkhas, Abu Dhabi, UAE and coastal hypersaline lagoons (Lagoa Vermelha and Brejo do Espinho) east of Rio de Janeiro, Brazil. An HRTEM study of samples from these three locations indicates a possible physical/chemical association between the Ca-dolomite and Mg-rich clays, demonstrating a probable co-precipitation. To test this hypothesis, we have conducted a series of biotic and abiotic laboratory experiments. If this syngenesis actually occurs in nature, what, if any, are the biogeochemical processes controlling these precipitation reactions? Our experiments were designed to determine the extent of the biotic versus abiotic component influencing the mineral precipitation and, in the case of a biotic influence, to understand the mechanism through which microorganisms might mediate the formation of clay minerals. The experiments were carried out in the Geomicrobiology Laboratory of ETH Zürich using cultures of living microbes and artificial organic compounds that simulate functional groups present in natural biofilms formed under both aerobic and anaerobic conditions. In addition, pure inorganic experiments were designed to understand possible physico-chemical conditions for diagenetic processes that could induce dissolution of Mg-carbonates and precipitation of Mg-rich clays. Our results show a remarkable biotic influence during the formation of clay minerals. Specifically, extracellular polymeric substances (EPS), released by microbes in their

Feeding in deep-sea demosponges: Influence of abiotic and biotic factors

Science.gov (United States)

Robertson, Leah M.; Hamel, Jean-François; Mercier, Annie

2017-09-01

In shallow benthic communities, sponges are widely recognized for their ability to contribute to food webs by cycling nutrients and mediating carbon fluxes through filter feeding. In comparison, little is known about filter feeding in deep-sea species and how it may be modulated by environmental conditions. Here, a rare opportunity to maintain live healthy deep-sea sponges for an extended period led to a preliminary experimental study of their feeding metrics. This work focused on demosponges collected from the continental slope of eastern Canada at 1000 m depth. Filtration rates (as clearance of phytoplankton cells) at holding temperature (6 °C) were positively correlated with food particle concentration, ranging on average from 18.8 to 160.6 cells ml-1 h-1 at nominal concentrations of 10,000-40,000 cells ml-1. Cell clearance was not significantly affected by decreasing seawater temperature, from 6 °C to 3 °C or 0 °C, although two of the sponges showed decreased filtration rates. Low pH ( 7.5) and the presence of a predatory sea star markedly depressed or inhibited feeding activity in all sponges tested. While performed under laboratory conditions on a limited number of specimens, this work highlights the possible sensitivity of deep-sea demosponges to various types and levels of biotic and abiotic factors, inferring a consequent vulnerability to natural and anthropogenic disturbances.

A Heavy Metal-Associated Protein (AcHMA1 from the Halophyte, Atriplex canescens (Pursh Nutt., Confers Tolerance to Iron and Other Abiotic Stresses When Expressed in Saccharomyces cerevisiae

Directory of Open Access Journals (Sweden)

Xin-Hua Sun

2014-08-01

Full Text Available Many heavy metals are essential for metabolic processes, but are toxic at elevated levels. Metal tolerance proteins provide resistance to this toxicity. In this study, we identified and characterized a heavy metal-associated protein, AcHMA1, from the halophyte, Atriplex canescens. Sequence analysis has revealed that AcHMA1 contains two heavy metal binding domains. Treatments with metals (Fe, Cu, Ni, Cd or Pb, PEG6000 and NaHCO3 highly induced AcHMA1 expression in A. canescens, whereas NaCl and low temperature decreased its expression. The role of AcHMA1 in metal stress tolerance was examined using a yeast expression system. Expression of the AcHMA1 gene significantly increased the ability of yeast cells to adapt to and recover from exposure to excess iron. AcHMA1 expression also provided salt, alkaline, osmotic and oxidant stress tolerance in yeast cells. Finally, subcellular localization of an AcHMA1/GFP fusion protein expressed in tobacco cells showed that AcHMA1 was localized in the plasma membrane. Thus, our results suggest that AcHMA1 encodes a membrane-localized metal tolerance protein that mediates the detoxification of iron in eukaryotes. Furthermore, AcHMA1 also participates in the response to abiotic stress.

Abiotic nitrate reduction in the presence of steel material and hydrogen in cementitious environments

International Nuclear Information System (INIS)

Truche, L.; Berger, G.; Albrecht, A.

2012-01-01

Document available in extended abstract form only. Abiotic nitrate reduction induced by different electron donors represents a major reaction of interest in the context of disposal of nuclear waste containing such oxyanions (Honda et al., 2006; Katsounaros et al., 2009). These wastes are characterized, amongst others by the coexistence of oxyanions (nitrate, phosphate, sulfate...) and potentially reducing agents such as organic matter, native metals and hydrogen gas formed or from package material via radiolysis or anaerobic corrosion. In addition to the large number of reactants present in the waste itself, the medium-level long-lived (MAVL) waste concept is based on large masses of concrete and steel in part used for primary waste containers as well as armored cement over pack and engineered barrier; a concept that guarantees the mechanical stability of both the waste container and the waste cell. In this experimental study we evaluate the consequences of steel material (carbon steel and 316L stainless steel) from waste canisters and construction material (concrete and Callovo- Oxfordian argillite), as well as magnetite as their possible corrosion by-products, on the reduction of aqueous nitrate in the presence of hydrogen. A parametric study (0 2 ) - ] 2+ , Fe 2+ ) that can act as electron donors. This experimental study demonstrates that abiotic nitrate reduction induced by the combination of steel materials and hydrogen is a likely process under waste cell conditions, thus applicable to cases where nitrate-bearing waste (i.e. nuclear) is disposed in near-surface or in deep geological settings. Depending on the nature of the steel, the reaction may exhibit different kinetic features that would require dedicated assessment. An increase in nitrate concentrat ions above the steel saturation level of 10 mM (Fig. 1; beyond the range of the current study) may also have an influence on reaction processes and kinetics and thus influence nitrate reactivity. (authors)

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.

Abiotic controls of emergent macrophyte density in a bedrock channel - The Cahaba River, AL (USA)

Science.gov (United States)

Vaughn, Ryan S.; Davis, Lisa

2015-10-01

Research examining bedrock channels is growing. Despite this, biotic-abiotic interactions remain a topic mostly addressed in alluvial systems. This research identified hydrogeomorphic factors operating at the patch-scale (100-102 m) in bedrock shoals of the Cahaba River (AL) that help determine the distribution of the emergent aquatic macrophyte, Justicia americana. Macrophyte patch density (number of stems/m2) and percent bedrock void surface area (rock surface area/m2 occupied by joints, fractures, and potholes) were measured (n = 24 within two bedrock shoals) using stem counts and underwater photography, respectively. One-dimensional hydrologic modeling (HEC-RAS 4.1.0) was completed for a section within a shoal to examine velocity and channel depth as controlling variables for macrophyte patch density. Results from binary logistic regression analysis identified depth and velocity as good predictors of the presence or absence of Justicia americana within shoal structures (depth p = 0.001, velocity p = 0.007), which is a similar finding to previous research conducted in alluvial systems. Correlation analysis between bedrock surface void area and stem density demonstrated a statistically significant positive correlation (r = 0.665, p = 0.01), elucidating a link between abiotic-biotic processes that may well be unique to bedrock channels. These results suggest that the amount of void space present in bedrock surfaces, in addition to localized depth and velocity, helps control macrophyte patch density in bedrock shoal complexes. The utility of geomorphology in explaining patch-scale habitat heterogeneity in this study highlights geomorphology's potential to help understand macrophyte habitat heterogeneity at the reach scale, while also demonstrating its promise for mapping and understanding habitat heterogeneity at the system scale.

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

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Antonela Markulj Kulundžić

2016-11-01

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

Dicty_cDB: Contig-U02963-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 3 ( CK246139 ) EST729776 potato callus cDNA library, normalized ... 36 0.066 2 ( CK260957 ) EST707035 potato abiotic stress cDNA libr...ary Sola... 36 0.066 2 ( CK264509 ) EST710587 potato abiotic stress cDNA library So...la... 36 0.066 2 ( CK270438 ) EST716516 potato abiotic stress cDNA library Sola.....e-12 3 ( FD432325 ) Atr01b_127_E02_C010.g1 FGP Male Amborella trichop... 50 4e-09 2 ( CF450348 ) EST686693 normalized cDNA library...GE498851 ) CCFT1427.b1_E22.ab1 CCF(STU) sunflower Helianthus... 42 0.005 2 ( DV105288 ) chiou01187 Subtractive cDNA library

An unified framework to integrate biotic, abiotic processes and human activities in spatially explicit models of agricultural landscapes

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Fabrice eVinatier

2016-02-01

Full Text Available Recent concern over possible ways to sustain ecosystem services has triggered important research worldwide on ecosystem processes at the landscape scale. Understanding this complexity of landscape functioning calls for coupled and spatially-explicit modelling approaches. However, disciplinary boundaries have limited the number of multi-process studies at the landscape scale, and current progress in coupling processes at this scale often reveals strong imbalance between biotic and abiotic processes, depending on the core discipline of the modellers. We propose a spatially-explicit, unified conceptual framework that allows researchers from different fields to develop a shared view of agricultural landscapes. In particular,we distinguish landscape elements that are mobile in space and represent biotic or abiotic objects (for example water, fauna or flora populations, and elements that are immobile and represent fixed landscape elements with a given geometry (for example ditch section or plot. The shared representation of these elements allows setting common objects and spatio-temporal process boundaries that may otherwise differ between disciplines. We present guidelines and an assessment of the applicability of this framework to a virtual landscape system with realistic properties. This framework allows the complex system to be represented with a limited set of concepts but leaves the possibility to include current modelling strategies specific to biotic or abiotic disciplines. Future operational challenges include model design, space and time discretization, and the availability of both landscape modelling platforms and data.

Functional and DNA-protein binding studies of WRKY transcription factors and their expression analysis in response to biotic and abiotic stress in wheat (Triticum aestivum L.).

Science.gov (United States)

Satapathy, Lopamudra; Kumar, Dhananjay; Kumar, Manish; Mukhopadhyay, Kunal

2018-01-01

WRKY, a plant-specific transcription factor family, plays vital roles in pathogen defense, abiotic stress, and phytohormone signalling. Little is known about the roles and function of WRKY transcription factors in response to rust diseases in wheat. In the present study, three TaWRKY genes encoding complete protein sequences were cloned. They belonged to class II and III WRKY based on the number of WRKY domains and the pattern of zinc finger structures. Twenty-two DNA-protein binding docking complexes predicted stable interactions of WRKY domain with W-box. Quantitative real-time-PCR using wheat near-isogenic lines with or without Lr28 gene revealed differential up- or down-regulation in response to biotic and abiotic stress treatments which could be responsible for their functional divergence in wheat. TaWRKY62 was found to be induced upon treatment with JA, MJ, and SA and reduced after ABA treatments. Maximum induction of six out of seven genes occurred at 48 h post inoculation due to pathogen inoculation. Hence, TaWRKY (49, 50 , 52 , 55 , 57, and 62 ) can be considered as potential candidate genes for further functional validation as well as for crop improvement programs for stress resistance. The results of the present study will enhance knowledge towards understanding the molecular basis of mode of action of WRKY transcription factor genes in wheat and their role during leaf rust pathogenesis in particular.

Isolation and molecular characterization of a novel WIN1/SHN1 ethylene-responsive transcription factor TdSHN1 from durum wheat (Triticum turgidum. L. subsp. durum).

Science.gov (United States)

Djemal, Rania; Khoudi, Habib

2015-11-01

Over the last decade, APETALA2/Ethylene Responsive Factor (AP2/ERF) proteins have become the subject of intensive research activity due to their involvement in a variety of biological processes. This research led to the identification of AP2/ERF genes in many species; however, little is known about these genes in durum wheat, one of the most important cereal crops in the world. In this study, a new member of the AP2/ERF transcription factor family, designated TdSHN1, was isolated from durum wheat using thermal asymetric interlaced PCR (TAIL-PCR) method. Protein sequence analysis showed that TdSHN1 contained an AP2/ERF domain of 63 amino acids and a putative nuclear localization signal (NLS). Phylogenetic analysis showed that TdSHN1 belongs to a group Va protein in the ERF subfamily which contains the Arabidopsis ERF proteins (SHN1, SHN2, and SHN3). Expression of TdSHN1 was strongly induced by salt, drought, abscisic acid (ABA), and cold. In planta, TdSHN1 protein was able to activate the transcription of GUS reporter gene driven by the GCC box and DRE element sequences. In addition, TdSHN1 was targeted to the nucleus when transiently expressed in tobacco epidermal cells. In transgenic yeast, overexpression of TdSHN1 increased tolerance to multiple abiotic stresses. Taken together, the results showed that TdSHN1 encodes an abiotic stress-inducible, transcription factor which confers abiotic stress tolerance in yeast. TdSHN1 is therefore a promising candidate for improvement of biotic and abiotic stress tolerance in wheat as well as other crops.

Integrated physiological and molecular approaches to improvement of abiotic stress tolerance in two pulse crops of the semi-arid tropics

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Arbind K. Choudhary

2018-04-01

Full Text Available Chickpea (Cicer arietinum L. and pigeonpea [Cajanus cajan L. (Millsp.] play an important role in mitigating protein malnutrition for millions of poor vegetarians living in regions of the semi-arid tropics. Abiotic stresses such as excess and limited soil moisture (water-logging and drought, heat and chilling (high and low temperature stresses, soil salinity, and acidity are major yield constraints, as these two crops are grown mostly under rainfed conditions in risk-prone marginal and degraded lands with few or no inputs. Losses due to such stresses vary from 30% to 100% depending on their severity. The literature abounds in basic information concerning screening techniques, physiological mechanisms, and genetics of traits associated with resistance/tolerance to abiotic stresses in these two crops. However, the final outcome in terms of resistant/tolerant varieties has been far from satisfactory. This situation calls for improving selection efficiency through precise phenotyping and genotyping under high-throughput controlled conditions using modern tools of genomics. In this review, we suggest that an integrated approach combining advances from genetics, physiology, and biotechnology needs to be used for higher precision and efficiency of breeding programs aimed at improving abiotic stress tolerance in both chickpea and pigeonpea.

Self-inhibition can limit biologically enhanced TCE dissolution from a TCE DNAPL.

Science.gov (United States)

Haest, P J; Springael, D; Seuntjens, P; Smolders, E

2012-11-01

Biodegradation of trichloroethene (TCE) near a Dense Non Aqueous Phase Liquid (DNAPL) can enhance the dissolution rate of the DNAPL by increasing the concentration gradient at the DNAPL-water interface. Two-dimensional flow-through sand boxes containing a TCE DNAPL and inoculated with a TCE dechlorinating consortium were set up to measure this bio-enhanced dissolution under anaerobic conditions. The total mass of TCE and daughter products in the effluent of the biotic boxes was 3-6 fold larger than in the effluent of the abiotic box. However, the mass of daughter products only accounted for 19-55% of the total mass of chlorinated compounds in the effluent, suggesting that bio-enhanced dissolution factors were maximally 1.3-2.2. The enhanced dissolution most likely primarily resulted from variable DNAPL distribution rather than biodegradation. Specific dechlorination rates previously determined in a stirred liquid medium were used in a reactive transport model to identify the rate limiting factors. The model adequately simulated the overall TCE degradation when predicted resident microbial numbers approached observed values and indicated an enhancement factor for TCE dissolution of 1.01. The model shows that dechlorination of TCE in the 2D box was limited due to the short residence time and the self-inhibition of the TCE degradation. A parameter sensitivity analysis predicts that the bio-enhanced dissolution factor for this TCE source zone can only exceed a value of 2 if the TCE self-inhibition is drastically reduced (when a TCE tolerant dehalogenating community is present) or if the DNAPL is located in a low-permeable layer with a small Darcy velocity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Comparative functional analysis of wheat (Triticum aestivum) zinc finger-containing glycine-rich RNA-binding proteins in response to abiotic stresses.

Science.gov (United States)

Xu, Tao; Gu, Lili; Choi, Min Ji; Kim, Ryeo Jin; Suh, Mi Chung; Kang, Hunseung

2014-01-01

Although the functional roles of zinc finger-containing glycine-rich RNA-binding proteins (RZs) have been characterized in several plant species, including Arabidopsis thaliana and rice (Oryza sativa), the physiological functions of RZs in wheat (Triticum aestivum) remain largely unknown. Here, the functional roles of the three wheat RZ family members, named TaRZ1, TaRZ2, and TaRZ3, were investigated using transgenic Arabidopsis plants under various abiotic stress conditions. Expression of TaRZs was markedly regulated by salt, dehydration, or cold stress. The TaRZ1 and TaRZ3 proteins were localized to the nucleus, whereas the TaRZ2 protein was localized to the nucleus, endoplasmic reticulum, and cytoplasm. Germination of all three TaRZ-expressing transgenic Arabidopsis seeds was retarded compared with that of wild-type seeds under salt stress conditions, whereas germination of TaRZ2- or TaRZ3-expressing transgenic Arabidopsis seeds was retarded under dehydration stress conditions. Seedling growth of TaRZ1-expressing transgenic plants was severely inhibited under cold or salt stress conditions, and seedling growth of TaRZ2-expressing plants was inhibited under salt stress conditions. By contrast, expression of TaRZ3 did not affect seedling growth of transgenic plants under any of the stress conditions. In addition, expression of TaRZ2 conferred freeze tolerance in Arabidopsis. Taken together, these results suggest that different TaRZ family members play various roles in seed germination, seedling growth, and freeze tolerance in plants under abiotic stress.

Performance of mesophilic anaerobic granules for removal of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) from aqueous solution

International Nuclear Information System (INIS)

An Chunjiang; He Yanling; Huang Guohe; Liu Yonghong

2010-01-01

The performance of mesophilic anaerobic granules to degrade octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) was investigated under various conditions. The results of batch experiments showed that anaerobic granules were capable of removing HMX from aqueous solution with high efficiency. Both biotic and abiotic mechanisms contributed to the removal of HMX by anaerobic granules under mesophilic conditions. Adsorption appeared to play a significant role in the abiotic process. Furthermore, HMX could be biodegraded by anaerobic granules as the sole substrate. After 16 days of incubation, 99.04% and 96.42% of total HMX could be removed by 1 g VSS/L acclimated and unacclimated granules, respectively. Vancomycin, an inhibitor of acetogenic bacteria, caused a significant inhibition of HMX biotransformation, while 2-bromoethanesulfonic acid, an inhibitor of methanogenic bacteria, only resulted in a slight decrease of metabolic activity. The presence of the glucose, as a suitable electron donor and carbon source, was found to enhance the degradation of HMX by anaerobic granules. Our study showed that sulfate had little adverse effects on biotransformation of HMX by anaerobic granules. However, nitrate had significant inhibitory effect on the extent of HMX removal especially in the initial period. This study offered good prospects of using high-rate anaerobic technology in the treatment of munition wastewater.

Intragenic HIV-1 env sequences that enhance gag expression

International Nuclear Information System (INIS)

Suptawiwat, Ornpreya; Sutthent, Ruengpung; Lee, T.-H.; Auewarakul, Prasert

2003-01-01

Expression of HIV-1 genes is regulated at multiple levels including the complex RNA splicing and transport mechanisms. Multiple cis-acting elements involved in these regulations have been previously identified in various regions of HIV-1 genome. Here we show that another cis-acting element was present in HIV-1 env region. This element enhanced the expression of Gag when inserted together with Rev response element (RRE) into a truncated HIV-1 genome in the presence of Rev. The enhancing activity was mapped to a 263-bp fragment in the gp41 region downstream to RRE. RNA analysis showed that it might function by promoting RNA stability and Rev-dependent RNA export. The enhancement was specific to Rev-dependent expression, since it did not enhance Gag expression driven by Sam68, a cellular protein that has been shown to be able to substitute for Rev in RNA export function

The Arabidopsis mutant cev1 links cell wall signaling to jasmonate and ethylene responses.

Science.gov (United States)

Ellis, Christine; Karafyllidis, Ioannis; Wasternack, Claus; Turner, John G

2002-07-01

Biotic and abiotic stresses stimulate the synthesis of jasmonates and ethylene, which, in turn, induce the expression of genes involved in stress response and enhance defense responses. The cev1 mutant has constitutive expression of stress response genes and has enhanced resistance to fungal pathogens. Here, we show that cev1 plants have increased production of jasmonate and ethylene and that its phenotype is suppressed by mutations that interrupt jasmonate and ethylene signaling. Genetic mapping, complementation analysis, and sequence analysis revealed that CEV1 is the cellulose synthase CeSA3. CEV1 was expressed predominantly in root tissues, and cev1 roots contained less cellulose than wild-type roots. Significantly, the cev1 mutant phenotype could be reproduced by treating wild-type plants with cellulose biosynthesis inhibitors, and the cellulose synthase mutant rsw1 also had constitutive expression of VSP. We propose that the cell wall can signal stress responses in plants.

Influence of abiotic factors on bacterial proliferation and anoxic survival of the sea mussel Mytilus edulis L.

NARCIS (Netherlands)

Babarro, J.M.F.; De Zwaan, A.

2002-01-01

The effect of several abiotic factors (salinity, temperature and pH) on bacterial proliferation and survival time of the sea mussel Mytilus edulis L. were studied under anoxic incubations. In addition, the presence in the incubation media of ammonium and the volatile fatty acids propionate and

Ecological relevance of strigolactones in nutrient uptake and other abiotic stresses, and in plant-microbe interactions below ground

NARCIS (Netherlands)

Andreo Jimenez, B.; Ruyter-Spira, C.P.; Bouwmeester, H.J.; Lopez-Raez, J.A.

2015-01-01

Background Plants are exposed to ever changing and often unfavourable environmental conditions, which cause both abiotic and biotic stresses. They have evolved sophisticated mechanisms to flexibly adapt themselves to these stress conditions. To achieve such adaptation, they need to control and

Earth, wind, and fire: Abiotic factors and the impacts of global environmental change on forest health

Science.gov (United States)

J.E. Lundquist; A.E. Camp; M.L. Tyrell; S.J. Seybold; P. Cannon; D.J. Lodge

2011-01-01

Trees do not just die; there is always a primary cause, and often contributing factors. Trees need adequate quantities of water, heat, light, nutrients, carbon dioxide, oxygen, and other abiotic resources to sustain life, growth, and reproduction. When these factors are deficient or excessive, they cause mortality. According to the concept of baseline mortality (...

A proposed abiotic reaction scheme for hydroxylamine and monochloramine under chloramination relevant drinking water conditions.

Science.gov (United States)

Wahman, David G; Speitel, Gerald E; Machavaram, Madhav V

2014-09-01

Drinking water monochloramine (NH2Cl) use may promote ammonia-oxidizing bacteria (AOB). AOB use (i) ammonia monooxygenase for biological ammonia (NH3) oxidation to hydroxylamine (NH2OH) and (ii) hydroxylamine oxidoreductase for NH2OH oxidation to nitrite. NH2Cl and NH2OH may react, providing AOB potential benefits and detriments. The NH2Cl/NH2OH reaction would benefit AOB by removing the disinfectant (NH2Cl) and releasing their growth substrate (NH3), but the NH2Cl/NH2OH reaction would also provide a possible additional inactivation mechanism besides direct NH2Cl reaction with cells. Because biological NH2OH oxidation supplies the electrons required for biological NH3 oxidation, the NH2Cl/NH2OH reaction provides a direct mechanism for NH2Cl to inhibit NH3 oxidation, starving the cell of reductant by preventing biological NH2OH oxidation. To investigate possible NH2Cl/NH2OH reaction implications on AOB, an understanding of the underlying abiotic reaction is first required. The present study conducted a detailed literature review and proposed an abiotic NH2Cl/NH2OH reaction scheme (RS) for chloramination relevant drinking water conditions (μM concentrations, air saturation, and pH 7-9). Next, RS literature based kinetics and end-products were evaluated experimentally between pHs 7.7 and 8.3, representing (i) the pH range for future experiments with AOB and (ii) mid-range pHs typically found in chloraminated drinking water. In addition, a (15)N stable isotope experiment was conducted to verify nitrous oxide and nitrogen gas production and their nitrogen source. Finally, the RS was slightly refined using the experimental data and an AQUASIM implemented kinetic model. A chloraminated drinking water relevant RS is proposed and provides the abiotic reaction foundation for future AOB biotic experiments. Published by Elsevier Ltd.

The relative contributions of biological and abiotic processes to carbon dynamics in subarctic sea ice

DEFF Research Database (Denmark)

Søgaard, Dorte Haubjerg; Thomas, David; Rysgaard, Søren

2013-01-01

Knowledge on the relative effects of biological activity and precipitation/dissolution of calcium carbonate (CaCO3) in influencing the air-ice CO2 exchange in sea-ice-covered season is currently lacking. Furthermore, the spatial and temporal occurrence of CaCO3 and other biogeochemical parameters...... in sea ice are still not well described. Here we investigated autotrophic and heterotrophic activity as well as the precipitation/dissolution of CaCO3 in subarctic sea ice in South West Greenland. Integrated over the entire ice season (71 days), the sea ice was net autotrophic with a net carbon fixation...... and CaCO3 precipitation. The net biological production could only explain 4 % of this sea-ice-driven CO2 uptake. Abiotic processes contributed to an air-sea CO2 uptake of 1.5 mmol m(-2) sea ice day(-1), and dissolution of CaCO3 increased the air-sea CO2 uptake by 36 % compared to a theoretical estimate...

The core regulatory network of the abscisic acid pathway in banana: genome-wide identification and expression analyses during development, ripening, and abiotic stress.

Science.gov (United States)

Hu, Wei; Yan, Yan; Shi, Haitao; Liu, Juhua; Miao, Hongxia; Tie, Weiwei; Ding, Zehong; Ding, XuPo; Wu, Chunlai; Liu, Yang; Wang, Jiashui; Xu, Biyu; Jin, Zhiqiang

2017-08-29

Abscisic acid (ABA) signaling plays a crucial role in developmental and environmental adaptation processes of plants. However, the PYL-PP2C-SnRK2 families that function as the core components of ABA signaling are not well understood in banana. In the present study, 24 PYL, 87 PP2C, and 11 SnRK2 genes were identified from banana, which was further supported by evolutionary relationships, conserved motif and gene structure analyses. The comprehensive transcriptomic analyses showed that banana PYL-PP2C-SnRK2 genes are involved in tissue development, fruit development and ripening, and response to abiotic stress in two cultivated varieties. Moreover, comparative expression analyses of PYL-PP2C-SnRK2 genes between BaXi Jiao (BX) and Fen Jiao (FJ) revealed that PYL-PP2C-SnRK2-mediated ABA signaling might positively regulate banana fruit ripening and tolerance to cold, salt, and osmotic stresses. Finally, interaction networks and co-expression assays demonstrated that the core components of ABA signaling were more active in FJ than in BX in response to abiotic stress, further supporting the crucial role of the genes in tolerance to abiotic stress in banana. This study provides new insights into the complicated transcriptional control of PYL-PP2C-SnRK2 genes, improves the understanding of PYL-PP2C-SnRK2-mediated ABA signaling in the regulation of fruit development, ripening, and response to abiotic stress, and identifies some candidate genes for genetic improvement of banana.

Disentangling effects of abiotic factors and biotic interactions on cross-taxon congruence in species turnover patterns of plants, moths and beetles.

Science.gov (United States)

Duan, Meichun; Liu, Yunhui; Yu, Zhenrong; Baudry, Jacques; Li, Liangtao; Wang, Changliu; Axmacher, Jan C

2016-04-01

High cross-taxon congruence in species diversity patterns is essential for the use of surrogate taxa in biodiversity conservation, but presence and strength of congruence in species turnover patterns, and the relative contributions of abiotic environmental factors and biotic interaction towards this congruence, remain poorly understood. In our study, we used variation partitioning in multiple regressions to quantify cross-taxon congruence in community dissimilarities of vascular plants, geometrid and arciinid moths and carabid beetles, subsequently investigating their respective underpinning by abiotic factors and biotic interactions. Significant cross-taxon congruence observed across all taxon pairs was linked to their similar responses towards elevation change. Changes in the vegetation composition were closely linked to carabid turnover, with vegetation structure and associated microclimatic conditions proposed causes of this link. In contrast, moth assemblages appeared to be dominated by generalist species whose turnover was weakly associated with vegetation changes. Overall, abiotic factors exerted a stronger influence on cross-taxon congruence across our study sites than biotic interactions. The weak congruence in turnover observed particularly between plants and moths highlights the importance of multi-taxon approaches based on groupings of taxa with similar turnovers, rather than the use of single surrogate taxa or environmental proxies, in biodiversity assessments.

Abiotic condensation synthesis of glyceride lipids and wax esters under simulated hydrothermal conditions.

Science.gov (United States)

Rushdi, Ahmed I; Simoneit, Bernd R T

2006-04-01

Precursor compounds for abiotic proto cellular membranes are necessary for the origin of life. Amphipathic compounds such as fatty acids and acyl glycerols are important candidates for micelle/bilayer/vesicle formation. Two sets of experiments were conducted to study dehydration reactions of model lipid precursors in aqueous media to form acyl polyols and wax esters, and to evaluate the stability and reactions of the products at elevated temperatures. In the first set, mixtures of n-nonadecanoic acid and ethylene glycol in water, with and without oxalic acid, were heated at discrete temperatures from 150 ( composite function)C to 300 ( composite function)C for 72 h. The products were typically alkyl alkanoates, ethylene glycolyl alkanoates, ethylene glycolyl bis-alkanoates and alkanols. The condensation products had maximum yields between 150 ( composite function)C and 250 ( composite function)C, and were detectable and thus stable under hydrothermal conditions to temperatures acid and glycerol were heated using the same experimental conditions, with and without oxalic acid, between 100 ( composite function)C and 250 ( composite function)C. The main condensation products were two isomers each of monoacylglycerols and diacylglycerols at all temperatures, as well as minor amounts of the fatty acid anhydride and methyl ester. The yield of glyceryl monoheptanoates generally increased with increasing temperature and glyceryl diheptanoates decreased noticeably with increasing temperature. The results indicate that condensation reactions and abiotic synthesis of organic lipid compounds under hydrothermal conditions occur easily, provided precursor concentrations are sufficiently high.

Identification of abiotic and biotic reductive dechlorination in a chlorinated ethene plume after thermal source remediation by means of isotopic and molecular biology tools

DEFF Research Database (Denmark)

Badin, Alice; Broholm, Mette Martina; Jacobsen, Carsten S.

2016-01-01

-Cl isotope analysis together with the almost absent VC 13C depletion in comparison to cDCE 13C depletion suggested that cDCE was subject to abiotic degradation due to the presence of pyrite, possible surface-bound iron (II) or reduced iron sulphides in the downgradient part of the plume. This interpretation...... reduced redox conditions which favor active reductive dechlorination and/or may lead to a series of redox reactions which may consecutively trigger biotically induced abiotic degradation. Finally, this study illustrates the valuable complementary application of compound-specific isotopic analysis combined...

Enhanced abiotic and biotic contributions to dechlorination of pentachlorophenol during Fe(III) reduction by an iron-reducing bacterium Clostridium beijerinckii Z

Energy Technology Data Exchange (ETDEWEB)

Xu, Yan [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); He, Yan, E-mail: yhe2006@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Feng, Xiaoli [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Liang, Luyi [Experiment Teaching Center for Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Xu, Jianming, E-mail: jmxu@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Brookes, Philip C.; Wu, Jianjun [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China)

2014-03-01

A novel Fe(III) reducing bacterium, Clostridium beijerinckii Z, was isolated from glucose amended paddy slurries, and shown to dechlorinate pentachlorophenol (PCP). Fifty percent of added PCP was removed by C. beijerinckii Z alone, which increased to 83% in the presence of both C. beijerinckii Z and ferrihydrite after 11 days of incubation. Without C. beijerinckii Z, the surface-bound Fe(II) also abiotically dechlorinated more than 40% of the added PCP. This indicated that the biotic dechlorination by C. beijerinckii Z is a dominant process causing PCP transformation through anaerobic dechlorination, and that the dechlorination rates can be accelerated by simultaneous reduction of Fe(III). A biochemical electron transfer coupling process between sorbed Fe(II) produced by C. beijerinckii Z and reductive dehalogenation is a possible mechanism. This finding increases our knowledge of the role of Fe(III) reducing genera of Clostridium in dechlorinating halogenated organic pollutants, such as PCP, in anaerobic paddy soils. - Highlights: • A novel Fe(III) reducing bacterium Clostridium beijerinckii Z was isolated and could dechlorinate pentachlorophenol. • Anaerobic transformation of PCP by C. beijerinckii Z could be accelerated by simultaneous reduction of Fe(III). • Biochemical electron transfer coupling between Fe redox cycling and reductive dechlorination was the mechanism involved. • The finding increases our knowledge of Clostridium sp. regarding their multiple functions for dechlorinating pollutants.

Enhanced abiotic and biotic contributions to dechlorination of pentachlorophenol during Fe(III) reduction by an iron-reducing bacterium Clostridium beijerinckii Z

International Nuclear Information System (INIS)

Xu, Yan; He, Yan; Feng, Xiaoli; Liang, Luyi; Xu, Jianming; Brookes, Philip C.; Wu, Jianjun

2014-01-01

A novel Fe(III) reducing bacterium, Clostridium beijerinckii Z, was isolated from glucose amended paddy slurries, and shown to dechlorinate pentachlorophenol (PCP). Fifty percent of added PCP was removed by C. beijerinckii Z alone, which increased to 83% in the presence of both C. beijerinckii Z and ferrihydrite after 11 days of incubation. Without C. beijerinckii Z, the surface-bound Fe(II) also abiotically dechlorinated more than 40% of the added PCP. This indicated that the biotic dechlorination by C. beijerinckii Z is a dominant process causing PCP transformation through anaerobic dechlorination, and that the dechlorination rates can be accelerated by simultaneous reduction of Fe(III). A biochemical electron transfer coupling process between sorbed Fe(II) produced by C. beijerinckii Z and reductive dehalogenation is a possible mechanism. This finding increases our knowledge of the role of Fe(III) reducing genera of Clostridium in dechlorinating halogenated organic pollutants, such as PCP, in anaerobic paddy soils. - Highlights: • A novel Fe(III) reducing bacterium Clostridium beijerinckii Z was isolated and could dechlorinate pentachlorophenol. • Anaerobic transformation of PCP by C. beijerinckii Z could be accelerated by simultaneous reduction of Fe(III). • Biochemical electron transfer coupling between Fe redox cycling and reductive dechlorination was the mechanism involved. • The finding increases our knowledge of Clostridium sp. regarding their multiple functions for dechlorinating pollutants

Substituted N-Phenylpyrazine-2-carboxamides, Their Synthesis and Evaluation as Herbicides and Abiotic Elicitors

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Katarína Kráľová

2007-12-01

Full Text Available The condensation of substituted pyrazine-2-carboxylic acid chlorides with ring-substituted anilines yielded five substituted pyrazine-2-carboxylic acid amides. Thesynthesis, and analytical, lipophilicity and biological data of the newly synthesizedcompounds are presented in this paper. The photosynthesis inhibition, antialgal activityand the effect of a series of pyrazine derivatives as abiotic elicitors on the accumulation offlavonoids in a callus culture of Ononis arvensis (L. were investigated. The most activeinhibitor of the oxygen evolution rate in spinach chloroplasts was 6-chloro-pyrazine-2-carboxylic acid (3-iodo-4-methylphenyl-amide (2, IC50 = 51.0 μmol·L-1. The highestreduction of chlorophyll content in Chlorella vulgaris was found for 5-tert-butyl-N-(4-chloro-3-methylphenyl-pyrazine-2-carboxamide (3, IC50 = 44.0 μmol·L-1. The maximalflavonoid production (about 900% was reached after a twelve-hour elicitation processwith 6-chloropyrazine-2-carboxylic acid (3-iodo-4-methylphenyl-amide (2.

Evaluation of candidate reference genes for normalization of quantitative RT-PCR in soybean tissues under various abiotic stress conditions.

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Dung Tien Le

Full Text Available Quantitative RT-PCR can be a very sensitive and powerful technique for measuring differential gene expression. Changes in gene expression induced by abiotic stresses are complex and multifaceted, which make determining stably expressed genes for data normalization difficult. To identify the most suitable reference genes for abiotic stress studies in soybean, 13 candidate genes collected from literature were evaluated for stability of expression under dehydration, high salinity, cold and ABA (abscisic acid treatments using delta CT and geNorm approaches. Validation of reference genes indicated that the best reference genes are tissue- and stress-dependent. With respect to dehydration treatment, the Fbox/ABC, Fbox/60s gene pairs were found to have the highest expression stability in the root and shoot tissues of soybean seedlings, respectively. Fbox and 60s genes are the most suitable reference genes across dehydrated root and shoot tissues. Under salt stress the ELF1b/IDE and Fbox/ELF1b are the most stably expressed gene pairs in roots and shoots, respectively, while 60s/Fbox is the best gene pair in both tissues. For studying cold stress in roots or shoots, IDE/60s and Fbox/Act27 are good reference gene pairs, respectively. With regard to gene expression analysis under ABA treatment in either roots, shoots or across these tissues, 60s/ELF1b, ELF1b/Fbox and 60s/ELF1b are the most suitable reference genes, respectively. The expression of ELF1b/60s, 60s/Fbox and 60s/Fbox genes was most stable in roots, shoots and both tissues, respectively, under various stresses studied. Among the genes tested, 60s was found to be the best reference gene in different tissues and under various stress conditions. The highly ranked reference genes identified from this study were proved to be capable of detecting subtle differences in expression rates that otherwise would be missed if a less stable reference gene was used.

Metabolomics reveals biotic and abiotic elicitor effects on the soft coral Sarcophyton ehrenbergi terpenoid content

OpenAIRE

Farag, Mohamed A.; Al-Mahdy, Dalia A.; Meyer, Achim; Westphal, Hildegard; Wessjohann, Ludger A.

2017-01-01

The effects of six biotic and abiotic elicitors, i.e. MeJA (methyl jasmonate), SA (salicylic acid), ZnCl2, glutathione and ?-glucan BG (fungal elicitor), and wounding, on the secondary metabolite accumulation in the soft coral Sarcophyton ehrenbergi were assessed. Upon elicitation, metabolites were extracted and analysed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Except for MeJA, no differences in photosynthetic efficiency were observed after treatments, suggestin...

Auxin Response Factors (ARFs are potential mediators of auxin action in tomato response to biotic and abiotic stress (Solanum lycopersicum.

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Sarah Bouzroud

Full Text Available Survival biomass production and crop yield are heavily constrained by a wide range of environmental stresses. Several phytohormones among which abscisic acid (ABA, ethylene and salicylic acid (SA are known to mediate plant responses to these stresses. By contrast, the role of the plant hormone auxin in stress responses remains so far poorly studied. Auxin controls many aspects of plant growth and development, and Auxin Response Factors play a key role in the transcriptional activation or repression of auxin-responsive genes through direct binding to their promoters. As a mean to gain more insight on auxin involvement in a set of biotic and abiotic stress responses in tomato, the present study uncovers the expression pattern of SlARF genes in tomato plants subjected to biotic and abiotic stresses. In silico mining of the RNAseq data available through the public TomExpress web platform, identified several SlARFs as responsive to various pathogen infections induced by bacteria and viruses. Accordingly, sequence analysis revealed that 5' regulatory regions of these SlARFs are enriched in biotic and abiotic stress-responsive cis-elements. Moreover, quantitative qPCR expression analysis revealed that many SlARFs were differentially expressed in tomato leaves and roots under salt, drought and flooding stress conditions. Further pointing to the putative role of SlARFs in stress responses, quantitative qPCR expression studies identified some miRNA precursors as potentially involved in the regulation of their SlARF target genes in roots exposed to salt and drought stresses. These data suggest an active regulation of SlARFs at the post-transcriptional level under stress conditions. Based on the substantial change in the transcript accumulation of several SlARF genes, the data presented in this work strongly support the involvement of auxin in stress responses thus enabling to identify a set of candidate SlARFs as potential mediators of biotic and abiotic

Impact of phenolic compounds and related enzymes in Sorghum varieties for resistance and susceptibility to biotic and abiotic stresses

NARCIS (Netherlands)

Dicko, M.H.; Gruppen, H.; Barro, C.; Traore, A.S.; Berkel, van W.J.H.; Voragen, A.G.J.

2005-01-01

Contents of phenolic compounds and related enzymes before and after sorghum grain germination were compared between varieties either resistant or susceptible to biotic (sooty stripe, sorghum midge, leaf anthracnose, striga, and grain molds) and abiotic (lodging, drought resistance, and photoperiod

Detection of Abiotic Methane in Terrestrial Continental Hydrothermal Systems: Implications for Methane on Mars

Science.gov (United States)

Socki, Richard A.; Niles, Paul B.; Gibson, Everett K., Jr.; Romanek, Christopher S.; Zhang, Chuanlun L.; Bissada, Kadry K.

2008-01-01

The recent detection of methane in the Martian atmosphere and the possibility that its origin could be attributed to biological activity, have highlighted the importance of understanding the mechanisms of methane formation and its usefulness as a biomarker. Much debate has centered on the source of the methane in hydrothermal fluids, whether it is formed biologically by microorganisms, diagenetically through the decomposition of sedimentary organic matter, or inorganically via reduction of CO2 at high temperatures. Ongoing research has now shown that much of the methane present in sea-floor hydrothermal systems is probably formed through inorganic CO2 reduction processes at very high temperatures (greater than 400 C). Experimental results have indicated that methane might form inorganically at temperatures lower still, however these results remain controversial. Currently, methane in continental hydrothermal systems is thought to be formed mainly through the breakdown of sedimentary organic matter and carbon isotope equilibrium between CO2 and CH4 is thought to be rarely present if at all. Based on isotopic measurements of CO2 and CH4 in two continental hydrothermal systems, we suggest that carbon isotope equilibration exists at temperatures as low as 155 C. This would indicate that methane is forming through abiotic CO2 reduction at lower temperatures than previously thought and could bolster arguments for an abiotic origin of the methane detected in the martian atmosphere.

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

Science.gov (United States)

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

The HIV1 protein Vpr acts to enhance constitutive DCAF1-dependent UNG2 turnover.

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Xiaoyun Wen

Full Text Available The HIV1 protein Vpr assembles with and acts through an ubiquitin ligase complex that includes DDB1 and cullin 4 (CRL4 to cause G2 cell cycle arrest and to promote degradation of both uracil DNA glycosylase 2 (UNG2 and single-strand selective mono-functional uracil DNA glycosylase 1 (SMUG1. DCAF1, an adaptor protein, is required for Vpr-mediated G2 arrest through the ubiquitin ligase complex. In work described here, we used UNG2 as a model substrate to study how Vpr acts through the ubiquitin ligase complex. We examined whether DCAF1 is essential for Vpr-mediated degradation of UNG2 and SMUG1. We further investigated whether Vpr is required for recruiting substrates to the ubiquitin ligase or acts to enhance its function and whether this parallels Vpr-mediated G2 arrest.We found that DCAF1 plays an important role in Vpr-independent UNG2 and SMUG1 depletion. UNG2 assembled with the ubiquitin ligase complex in the absence of Vpr, but Vpr enhanced this interaction. Further, Vpr-mediated enhancement of UNG2 degradation correlated with low Vpr expression levels. Vpr concentrations exceeding a threshold blocked UNG2 depletion and enhanced its accumulation in the cell nucleus. A similar dose-dependent trend was seen for Vpr-mediated cell cycle arrest.This work identifies UNG2 and SMUG1 as novel targets for CRL4(DCAF1-mediated degradation. It further shows that Vpr enhances rather than enables the interaction between UNG2 and the ubiquitin ligase. Vpr augments CRL4(DCAF1-mediated UNG2 degradation at low concentrations but antagonizes it at high concentrations, allowing nuclear accumulation of UNG2. Further, the protein that is targeted to cause G2 arrest behaves much like UNG2. Our findings provide the basis for determining whether the CRL4(DCAF1 complex is alone responsible for cell cycle-dependent UNG2 turnover and will also aid in establishing conditions necessary for the identification of additional targets of Vpr-enhanced degradation.

Expression of an engineered heterologous antimicrobial peptide in potato alters plant development and mitigates normal abiotic and biotic responses.

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Ravinder K Goyal

Full Text Available Antimicrobial cationic peptides (AMPs are ubiquitous small proteins used by living cells to defend against a wide spectrum of pathogens. Their amphipathic property helps their interaction with negatively charged cellular membrane of the pathogen causing cell lysis and death. AMPs also modulate signaling pathway(s and cellular processes in animal models; however, little is known of cellular processes other than the pathogen-lysis phenomenon modulated by AMPs in plants. An engineered heterologous AMP, msrA3, expressed in potato was previously shown to cause resistance of the transgenic plants against selected fungal and bacterial pathogens. These lines together with the wild type were studied for growth habits, and for inducible defense responses during challenge with biotic (necrotroph Fusarium solani and abiotic stressors (dark-induced senescence, wounding and temperature stress. msrA3-expression not only conferred protection against F. solani but also delayed development of floral buds and prolonged vegetative phase. Analysis of select gene transcript profiles showed that the transgenic potato plants were suppressed in the hypersensitive (HR and reactive oxygen species (ROS responses to both biotic and abiotic stressors. Also, the transgenic leaves accumulated lesser amounts of the defense hormone jasmonic acid upon wounding with only a slight change in salicylic acid as compared to the wild type. Thus, normal host defense responses to the pathogen and abiotic stressors were mitigated by msrA3 expression suggesting MSRA3 regulates a common step(s of these response pathways. The stemming of the pathogen growth and mitigating stress response pathways likely contributes to resource reallocation for higher tuber yield.

Linking Species Traits to the Abiotic Template of Flowing Waters: Contrasting Eco physiologies Underlie Displacement of Zebra Mussels by Quagga Mussels in a Large River-Estuary

Science.gov (United States)

Casper, A. F.

2005-05-01

The St. Lawrence River-Estuary was the gateway of entry for dreissenids to North America and holds some of the oldest populations. The St. Lawrence also has four distinct physical-chemical water masses (a regional scale abiotic template) that both species inhabit. Despite their ecological similarities, quagga mussels are supplanting zebra mussels in much of their shared range. In order to try to better understand the changing distributions of these two species we compared glycogen, shell mass and tissue biomass in each of the water masses. This comparative physiological combined with experimental approaches (estuarine salinity experiments and reciprocal transplants) showed that while quagga mussels should dominate in most habitats, that abiotic/bioenergetic constraints in two regions (the Ottawa River plume and the freshwater-marine transition zone) might prevent them from dominating these locations. These findings are an example of how the interaction of landscape scale abiotic heterogeneity and a species-specific physiology can have strong impacts of distribution of biota large rivers.

A Dehydration-Induced Eukaryotic Translation Initiation Factor iso4G Identified in a Slow Wilting Soybean Cultivar Enhances Abiotic Stress Tolerance in Arabidopsis

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Juan P. Gallino

2018-03-01

Full Text Available Water is usually the main limiting factor for soybean productivity worldwide and yet advances in genetic improvement for drought resistance in this crop are still limited. In the present study, we investigated the physiological and molecular responses to drought in two soybean contrasting genotypes, a slow wilting N7001 and a drought sensitive TJS2049 cultivars. Measurements of stomatal conductance, carbon isotope ratios and accumulated dry matter showed that N7001 responds to drought by employing mechanisms resulting in a more efficient water use than TJS2049. To provide an insight into the molecular mechanisms that these cultivars employ to deal with water stress, their early and late transcriptional responses to drought were analyzed by suppression subtractive hybridization. A number of differentially regulated genes from N7001 were identified and their expression pattern was compared between in this genotype and TJS2049. Overall, the data set indicated that N7001 responds to drought earlier than TJ2049 by up-regulating a larger number of genes, most of them encoding proteins with regulatory and signaling functions. The data supports the idea that at least some of the phenotypic differences between slow wilting and drought sensitive plants may rely on the regulation of the level and timing of expression of specific genes. One of the genes that exhibited a marked N7001-specific drought induction profile encoded a eukaryotic translation initiation factor iso4G (GmeIFiso4G-1a. GmeIFiso4G-1a is one of four members of this protein family in soybean, all of them sharing high sequence identity with each other. In silico analysis of GmeIFiso4G-1 promoter sequences suggested a possible functional specialization between distinct family members, which can attain differences at the transcriptional level. Conditional overexpression of GmeIFiso4G-1a in Arabidopsis conferred the transgenic plants increased tolerance to osmotic, salt, drought and low

Abiotic/biotic coupling in the rhizosphere: a reactive transport modeling analysis

Science.gov (United States)

Lawrence, Corey R.; Steefel, Carl; Maher, Kate

2014-01-01

A new generation of models is needed to adequately simulate patterns of soil biogeochemical cycling in response changing global environmental drivers. For example, predicting the influence of climate change on soil organic matter storage and stability requires models capable of addressing complex biotic/abiotic interactions of rhizosphere and weathering processes. Reactive transport modeling provides a powerful framework simulating these interactions and the resulting influence on soil physical and chemical characteristics. Incorporation of organic reactions in an existing reactive transport model framework has yielded novel insights into soil weathering and development but much more work is required to adequately capture root and microbial dynamics in the rhizosphere. This endeavor provides many advantages over traditional soil biogeochemical models but also many challenges.

Episodic abiotic stress and Phytophthora ramorum blight in rhododendron: impacts on root infection, symptom expression and chemical management

Science.gov (United States)

Tatiana Roubtsova; Richard Bostock

2013-01-01

Of concern for disease management and certification programs in nursery ornamentals is that roots, when colonized by Phytophthora ramorum, may serve as a potential reservoir of inoculum. An additional complication is that the above ground portion of plants with root infections may be asymptomatic. Our central hypothesis is that mild abiotic...

Functional roles of the pepper RING finger protein gene, CaRING1, in abscisic acid signaling and dehydration tolerance.

Science.gov (United States)

Lim, Chae Woo; Hwang, Byung Kook; Lee, Sung Chul

2015-09-01

Plants are constantly exposed to a variety of biotic and abiotic stresses, which include pathogens and conditions of high salinity, low temperature, and drought. Abscisic acid (ABA) is a major plant hormone involved in signal transduction pathways that mediate the defense response of plants to abiotic stress. Previously, we isolated Ring finger protein gene (CaRING1) from pepper (Capsicum annuum), which is associated with resistance to bacterial pathogens, accompanied by hypersensitive cell death. Here, we report a new function of the CaRING1 gene product in the ABA-mediated defense responses of plants to dehydration stress. The expression of the CaRING1 gene was induced in pepper leaves treated with ABA or exposed to dehydration or NaCl. Virus-induced gene silencing of CaRING1 in pepper plants exhibited low degree of ABA-induced stomatal closure and high levels of transpirational water loss in dehydrated leaves. These led to be more vulnerable to dehydration stress in CaRING1-silenced pepper than in the control pepper, accompanied by reduction of ABA-regulated gene expression and low accumulation of ABA and H2O2. In contrast, CaRING1-overexpressing transgenic plants showed enhanced sensitivity to ABA during the seedling growth and establishment. These plants were also more tolerant to dehydration stress than the wild-type plants because of high ABA accumulation, enhanced stomatal closure and increased expression of stress-responsive genes. Together, these results suggest that the CaRING1 acts as positive factor for dehydration tolerance in Arabidopsis by modulating ABA biosynthesis and ABA-mediated stomatal closing and gene expression.

Arabidopsis thaliana Remorins Interact with SnRK1 and Play a Role in Susceptibility to Beet Curly Top Virus and Beet Severe Curly Top Virus

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Seungmin Son

2014-09-01

Full Text Available Remorins, a family of plant-specific proteins containing a variable N-terminal region and conserved C-terminal domain, play a role in various biotic and abiotic stresses, including host-microbe interactions. However, their functions remain to be completely elucidated, especially for the Arabidopsis thaliana remorin group 4 (AtREM4. To elucidate the role of remorins in Arabidopsis, we first showed that AtREM4s have typical molecular characteristics of the remorins, such as induction by various types of biotic and abiotic stresses, localization in plasma membrane and homo- and hetero-oligomeric interaction. Next, we showed that their loss-of-function mutants displayed reduced susceptibility to geminiviruses, Beet Curly Top Virus and Beet Severe Curly Top Virus, while overexpressors enhanced susceptibility. Moreover, we found that they interacted with SnRK1, which phosphorylated AtREM4.1, and were degraded by the 26S proteasome pathway. These results suggest that AtREM4s may be involved in the SnRK1-mediated signaling pathway and play a role as positive regulators of the cell cycle during geminivirus infection.

Abiotic and biotic factors responsible for antimonite oxidation in Agrobacterium tumefaciens GW4

Science.gov (United States)

Li, Jingxin; Yang, Birong; Shi, Manman; Yuan, Kai; Guo, Wei; Wang, Qian; Wang, Gejiao

2017-03-01

Antimonite [Sb(III)]-oxidizing bacteria can transform the toxic Sb(III) into the less toxic antimonate [Sb(V)]. Recently, the cytoplasmic Sb(III)-oxidase AnoA and the periplasmic arsenite [As(III)] oxidase AioAB were shown to responsible for bacterial Sb(III) oxidation, however, disruption of each gene only partially decreased Sb(III) oxidation efficiency. This study showed that in Agrobacterium tumefaciens GW4, Sb(III) induced cellular H2O2 content and H2O2 degradation gene katA. Gene knock-out/complementation of katA, anoA, aioA and anoA/aioA and Sb(III) oxidation and growth experiments showed that katA, anoA and aioA were essential for Sb(III) oxidation and resistance and katA was also essential for H2O2 resistance. Furthermore, linear correlations were observed between cellular H2O2 and Sb(V) content in vivo and chemical H2O2 and Sb(V) content in vitro (R2 = 0.93 and 0.94, respectively). These results indicate that besides the biotic factors, the cellular H2O2 induced by Sb(III) also catalyzes bacterial Sb(III) oxidation as an abiotic oxidant. The data reveal a novel mechanism that bacterial Sb(III) oxidation is associated with abiotic (cellular H2O2) and biotic (AnoA and AioAB) factors and Sb(III) oxidation process consumes cellular H2O2 which contributes to microbial detoxification of both Sb(III) and cellular H2O2.

Interfacial photochemistry of biogenic surfactants: a major source of abiotic volatile organic compounds.

Science.gov (United States)

Brüggemann, Martin; Hayeck, Nathalie; Bonnineau, Chloé; Pesce, Stéphane; Alpert, Peter A; Perrier, Sébastien; Zuth, Christoph; Hoffmann, Thorsten; Chen, Jianmin; George, Christian

2017-08-24

Films of biogenic compounds exposed to the atmosphere are ubiquitously found on the surfaces of cloud droplets, aerosol particles, buildings, plants, soils and the ocean. These air/water interfaces host countless amphiphilic compounds concentrated there with respect to in bulk water, leading to a unique chemical environment. Here, photochemical processes at the air/water interface of biofilm-containing solutions were studied, demonstrating abiotic VOC production from authentic biogenic surfactants under ambient conditions. Using a combination of online-APCI-HRMS and PTR-ToF-MS, unsaturated and functionalized VOCs were identified and quantified, giving emission fluxes comparable to previous field and laboratory observations. Interestingly, VOC fluxes increased with the decay of microbial cells in the samples, indicating that cell lysis due to cell death was the main source for surfactants and VOC production. In particular, irradiation of samples containing solely biofilm cells without matrix components exhibited the strongest VOC production upon irradiation. In agreement with previous studies, LC-MS measurements of the liquid phase suggested the presence of fatty acids and known photosensitizers, possibly inducing the observed VOC production via peroxy radical chemistry. Up to now, such VOC emissions were directly accounted to high biological activity in surface waters. However, the results obtained suggest that abiotic photochemistry can lead to similar emissions into the atmosphere, especially in less biologically-active regions. Furthermore, chamber experiments suggest that oxidation (O 3 /OH radicals) of the photochemically-produced VOCs leads to aerosol formation and growth, possibly affecting atmospheric chemistry and climate-related processes, such as cloud formation or the Earth's radiation budget.

Abiotic and biotic controls on local spatial distribution and performance of Boechera stricta

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KUSUM J NAITHANI

2014-07-01

Full Text Available This study investigates the relative influence of biotic and abiotic factors on community dynamics using an integrated approach and highlights the influence of space on genotypic and phenotypic traits in plant community structure. We examined the relative influence of topography, environment, spatial distance, and intra- and interspecific interactions on spatial distribution and performance of Boechera stricta (rockcress, a close perennial relative of model plant Arabidopsis. First, using Bayesian kriging, we mapped the topography and environmental gradients and explored the spatial distribution of naturally occurring rockcress plants and two neighbors, Taraxacum officinale (dandelion and Solidago missouriensis (goldenrod found in close proximity within a typical diverse meadow community across topographic and environmental gradients. We then evaluated direct and indirect relationships among variables using Mantel path analysis and developed a network displaying abiotic and biotic interactions in this community. We found significant spatial autocorrelation among rockcress individuals, either because of common microhabitats as displayed by high density of individuals at lower elevation and high soil moisture area, or limited dispersal as shown by significant spatial autocorrelation of naturally occurring inbred lines, or a combination of both. Goldenrod and dandelion density around rockcress does not show any direct relationship with rockcress fecundity, possibly due to spatial segregation of resources. However, dandelion density around rockcress shows an indirect negative influence on rockcress fecundity via herbivory, indicating interspecific competition. Overall, we suggest that common microhabitat preference and limited dispersal are the main drivers for spatial distribution. However, intra-specific interactions and insect herbivory are the main drivers of rockcress performance in the meadow community.

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.

SEASONALITY OF THE LEAF MINER, LEVEL OF PREDATION AND TEMPORAL OCCURRENCE OF RUST CORRELATED TO ABIOTIC FACTORS

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B. M. R. Melo

2018-04-01

Full Text Available The coffee leaf miner and a rust are considered as major diseases that are able to reduce productivity in coffee plantations. These agents are influenced by abiotic factors, and their occurrence may suffer oscillation over the years. The objective of this study was to evaluate the seasonal fluctuation of the coffee leaf miner, incidence of coffee prediction and rust, correlated with abiotic factors. The study was performed IFSULDEMINAS-Campus Inconfidentes, in a coffee crop of the cultivar Rubi. A sample for a rust and a coffee leaf miner, in addition to the middle and upper third of the plants, totaling 42 plants in the study area. At the same sampling point, perform soil analysis to correlate nutrients as studied variables. The Pearson correlation of the biotic variables was performed with a precipitation and fertility, a rate of 1 and 5% probability. It was verified that the rust cycle alternated its incidence for the same period in different years and the miner showed behavior coincident to the driest periods of the year. Data not available on precipitation data and number of mines. These diseases had no significant correlation with the fertility parameter. The coffee leaf miner yielded higher rates of occurrence in June and December of 2014. It was concluded that the percentage of coffee leaf miner was higher in the months with lower rainfall indices or no longer summer period; What is it you want to know about the one-time development that may have been influenced by the nearby woods under study and the rust alternated the peaks of occurrence for the two autumners, correlating with a precipitation.

Transformation and biodegradation of 1,2,3-trichloropropane (TCP).

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Samin, Ghufrana; Janssen, Dick B

2012-09-01

1,2,3-Trichloropropane (TCP) is a persistent groundwater pollutant and a suspected human carcinogen. It is also is an industrial chemical waste that has been formed in large amounts during epichlorohydrin manufacture. In view of the spread of TCP via groundwater and its toxicity, there is a need for cheap and efficient technologies for the cleanup of TCP-contaminated sites. In situ or on-site bioremediation of TCP is an option if biodegradation can be achieved and stimulated. This paper presents an overview of methods for the remediation of TCP-contaminated water with an emphasis on the possibilities of biodegradation. Although TCP is a xenobiotic chlorinated compound of high chemical stability, a number of abiotic and biotic conversions have been demonstrated, including abiotic oxidative conversion in the presence of a strong oxidant and reductive conversion by zero-valent zinc. Biotransformations that have been observed include reductive dechlorination, monooxygenase-mediated cometabolism, and enzymatic hydrolysis. No natural organisms are known that can use TCP as a carbon source for growth under aerobic conditions, but anaerobically TCP may serve as electron acceptor. The application of biodegradation is hindered by low degradation rates and incomplete mineralization. Protein engineering and genetic modification can be used to obtain microorganisms with enhanced TCP degradation potential.

Mediterranean coastal dune systems: Which abiotic factors have the most influence on plant communities?

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Ruocco, Matteo; Bertoni, Duccio; Sarti, Giovanni; Ciccarelli, Daniela

2014-08-01

Mediterranean coastal dunes are dynamic and heterogeneous ecosystems characterised by a strong interaction between abiotic and biotic factors. The present study aimed to adopt a multidisciplinary approach - integrating data on dune morphology, sediment texture and soil parameters as well as shoreline trend - in order to define which are the abiotic factors that most affect the distribution and composition of Mediterranean plant dune communities. The study was carried out in two protected areas, located in central Italy, subjected to different shoreline trends in recent years. 75 plots were identified along eleven randomly positioned cross-shore transects, starting from the beach continuing up to the plant communities of the backdunes. In each plot floristic and environmental data - such as distance to the coastline, plot altitude, inclination, shoreline trend, mean grain-size, sorting, pH, conductivity and organic matter concentration - were collected. The analyses revealed significant changes of vegetational cover, dune morphology and geopedological features along the coast-to-inland gradient. Relationships between vegetation composition and environmental factors were investigated through Canonical Correspondence Analysis (CCA). Four factors - distance to the coastline, mean grain-size, shoreline trend and organic matter - were found to be closely correlated with the floristic composition of plant communities. Finally, soil properties were highlighted as the most determinant factors of community zonation in these Mediterranean coastal dune ecosystems. These results could be taken into account by local managers in conservation actions such as protecting the eroding foredunes as well as in artificial dune reconstructions.

Abiotic nitrogen fixation on terrestrial planets: reduction of NO to ammonia by FeS.

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Summers, David P; Basa, Ranor C B; Khare, Bishun; Rodoni, David

2012-02-01

Understanding the abiotic fixation of nitrogen and how such fixation can be a supply of prebiotic nitrogen is critical for understanding both the planetary evolution of, and the potential origin of life on, terrestrial planets. As nitrogen is a biochemically essential element, sources of biochemically accessible nitrogen, especially reduced nitrogen, are critical to prebiotic chemistry and the origin of life. Loss of atmospheric nitrogen can result in loss of the ability to sustain liquid water on a planetary surface, which would impact planetary habitability and hydrological processes that shape the surface. It is known that NO can be photochemically converted through a chain of reactions to form nitrate and nitrite, which can be subsequently reduced to ammonia. Here, we show that NO can also be directly reduced, by FeS, to ammonia. In addition to removing nitrogen from the atmosphere, this reaction is particularly important as a source of reduced nitrogen on an early terrestrial planet. By converting NO directly to ammonia in a single step, ammonia is formed with a higher product yield (~50%) than would be possible through the formation of nitrate/nitrite and subsequent conversion to ammonia. In conjunction with the reduction of NO, there is also a catalytic disproportionation at the mineral surface that converts NO to NO₂ and N₂O. The NO₂ is then converted to ammonia, while the N₂O is released back in the gas phase, which provides an abiotic source of nitrous oxide.

[Effect of abiotic and biotic factors on the structural and functional organization of the saline lake ecosystems in Crimea].

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Balushkina, E V; Golubkov, S M; Golubkov, M S; Litvinchuk, L F; Shadrin, N V

2009-01-01

Decrease of both zooplankton and zoobenthos species richness and a trend toward decrease of their biomass with the salinity increase was recorded in the hypersaline lakes of Crimea. The most of structural and functional characteristics of macrobenthos is positively correlated with abiotic and biotic characteristics of those lakes. Abundance, biomass, productivity of macrobenthos and ration of non-predating macrozoobenthos decrease with salinity increase, while they increase with the depth and growth of amount of chlorophyll a and primary production. Macrozoobenthos portion in the total zooplankton and macrozoobenthos biomass decreases with both salinity and depth increase. Zooplankton community is less controlled by abiotic factors as compared to macrozoobenthos, while the former's species number significantly decrease with salinity increase. Effect of salinity on zooplankton biomass is slightly significant, unlike that of macrozoobenthos. Comparison of total amount of rations of zooplankton and macrozoobenthos with amount of primary production indicates intense trophic interactions in the lakes under study.

Cyclophilin B enhances HIV-1 infection.

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DeBoer, Jason; Madson, Christian J; Belshan, Michael

2016-02-01

Cyclophilin B (CypB) is a member of the immunophilin family and intracellular chaperone. It predominantly localizes to the ER, but also contains a nuclear localization signal and is secreted from cells. CypB has been shown to interact with the Gag protein of human immunodeficiency type 1 (HIV-1). Several proteomic and genetic studies identified it as a potential factor involved in HIV replication. Herein, we show that over-expression of CypB enhances HIV infection by increasing nuclear import of viral DNA. This enhancement was unaffected by cyclosporine treatment and requires the N-terminus of the protein. The N-terminus contains an ER leader sequence, putative nuclear localization signal, and is required for secretion. Deletion of the N-terminus resulted in mislocalization from the ER and suppression of HIV infection. Passive transfer experiments showed that secreted CypB did not impact HIV infection. Combined, these experiments show that intracellular CypB modulates a pathway of HIV nuclear import. Copyright © 2015 Elsevier Inc. All rights reserved.

Overexpression of transcription factor OsWR2 1 regulates wax/cutin biosynthesis and enhances drought tolerance in rice

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Drought is the major abiotic stress limiting crop production. Plant cuticle represents the outer-most layer of the epidermis and previous studies demonstrate its association with plant response to climatological drought. We report here the functional characterization of the rice ((Oryza sativa L.) W...

Grin1 receptor deletion within CRF neurons enhances fear memory.

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Georgette Gafford

Full Text Available Corticotropin releasing factor (CRF dysregulation is implicated in mood and anxiety disorders such as posttraumatic stress disorder (PTSD. CRF is expressed in areas engaged in fear and anxiety processing including the central amygdala (CeA. Complicating our ability to study the contribution of CRF-containing neurons to fear and anxiety behavior is the wide variety of cell types in which CRF is expressed. To manipulate specific subpopulations of CRF containing neurons, our lab has developed a mouse with a Cre recombinase gene driven by a CRF promoter (CRFp3.0Cre (Martin et al., 2010. In these studies, mice that have the gene that encodes NR1 (Grin1 flanked by loxP sites (floxed were crossed with our previously developed CRFp3.0Cre mouse to selectively disrupt Grin1 within CRF containing neurons (Cre+/fGrin1+. We find that disruption of Grin1 in CRF neurons did not affect baseline levels of anxiety, locomotion, pain sensitivity or exploration of a novel object. However, baseline expression of Grin1 was decreased in Cre+/fGrin1+ mice as measured by RTPCR. Cre+/fGrin1+ mice showed enhanced auditory fear acquisition and retention without showing any significant effect on fear extinction. We measured Gria1, the gene that encodes AMPAR1 and the CREB activator Creb1 in the amygdala of Cre+/fGrin1+ mice after fear conditioning. Both Gria1 and Creb1 were enhanced in the amygdala after training. To determine if the Grin1-expressing CRF neurons within the CeA are responsible for the enhancement of fear memory in adults, we infused a lentivirus with Cre driven by a CRF promoter (LV pCRF-Cre/fGrin1+ into the CeA of floxed Grin1 mice. Cre driven deletion of Grin1 specifically within CRF expressing cells in the CeA also resulted in enhanced fear memory acquisition and retention. Altogether, these findings suggest that selective disruption of Grin1 within CeA CRF neurons strongly enhances fear memory.

The SULTR gene family in maize (Zea mays L.): Gene cloning and expression analyses under sulfate starvation and abiotic stress.

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Huang, Qin; Wang, Meiping; Xia, Zongliang

2018-01-01

Sulfur is an essential macronutrient required for plant growth, development and stress responses. The family of sulfate transporters (SULTRs) mediates the uptake and translocation of sulfate in higher plants. However, basic knowledge of the SULTR gene family in maize (Zea mays L.) is scarce. In this study, a genome-wide bioinformatic analysis of SULTR genes in maize was conducted, and the developmental expression patterns of the genes and their responses to sulfate starvation and abiotic stress were further investigated. The ZmSULTR family includes eight putative members in the maize genome and is clustered into four groups in the phylogenetic tree. These genes displayed differential expression patterns in various organs of maize. For example, expression of ZmSULTR1;1 and ZmSULTR4;1 was high in roots, and transcript levels of ZmSULTR3;1 and ZmSULTR3;3 were high in shoots. Expression of ZmSULTR1;2, ZmSULTR2;1, ZmSULTR3;3, and ZmSULTR4;1 was high in flowers. Also, these eight genes showed differential responses to sulfate deprivation in roots and shoots of maize seedlings. Transcript levels of ZmSULTR1;1, ZmSULTR1;2, and ZmSULTR3;4 were significantly increased in roots during 12-day-sulfate starvation stress, while ZmSULTR3;3 and ZmSULTR3;5 only showed an early response pattern in shoots. In addition, dynamic transcriptional changes determined via qPCR revealed differential expression profiles of these eight ZmSULTR genes in response to environmental stresses such as salt, drought, and heat stresses. Notably, all the genes, except for ZmSULTR3;3, were induced by drought and heat stresses. However, a few genes were induced by salt stress. Physiological determination showed that two important thiol-containing compounds, cysteine and glutathione, increased significantly under these abiotic stresses. The results suggest that members of the SULTR family might function in adaptations to sulfur deficiency stress and adverse growing environments. This study will lay a

Role of miRNAs and siRNAs in biotic and abiotic stress responses of plants

KAUST Repository

Khraiwesh, Basel

2012-02-01

Small, non-coding RNAs are a distinct class of regulatory RNAs in plants and animals that control a variety of biological processes. In plants, several classes of small RNAs with specific sizes and dedicated functions have evolved through a series of pathways. The major classes of small RNAs include microRNAs (miRNAs) and small interfering RNAs (siRNAs), which differ in their biogenesis. miRNAs control the expression of cognate target genes by binding to reverse complementary sequences, resulting in cleavage or translational inhibition of the target RNAs. siRNAs have a similar structure, function, and biogenesis as miRNAs but are derived from long double-stranded RNAs and can often direct DNA methylation at target sequences. Besides their roles in growth and development and maintenance of genome integrity, small RNAs are also important components in plant stress responses. One way in which plants respond to environmental stress is by modifying their gene expression through the activity of small RNAs. Thus, understanding how small RNAs regulate gene expression will enable researchers to explore the role of small RNAs in biotic and abiotic stress responses. This review focuses on the regulatory roles of plant small RNAs in the adaptive response to stresses. This article is part of a Special Issue entitled: Plant gene regulation in response to abiotic stress. © 2011 Elsevier B.V.

ThWRKY4 from Tamarix hispida Can Form Homodimers and Heterodimers and Is Involved in Abiotic Stress Responses

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Liuqiang Wang

2015-11-01

Full Text Available WRKY proteins are a large family of transcription factors that are involved in diverse developmental processes and abiotic stress responses in plants. However, our knowledge of the regulatory mechanisms of WRKYs participation in protein–protein interactions is still fragmentary, and such protein–protein interactions are fundamental in understanding biological networks and the functions of proteins. In this study, we report that a WRKY protein from Tamarix hispida, ThWRKY4, can form both homodimers and heterodimers with ThWRKY2 and ThWRKY3. In addition, ThWRKY2 and ThWRKY3 can both bind to W-box motif with binding affinities similar to that of ThWRKY4. Further, the expression patterns of ThWRKY2 and ThWRKY3 are similar to that of ThWRKY4 when plants are exposed to abscisic acid (ABA. Subcellular localization shows that these three ThWRKY proteins are nuclear proteins. Taken together, these results demonstrate that ThWRKY4 is a dimeric protein that can form functional homodimers or heterodimers that are involved in abiotic stress responses.

Effects of soil abiotic factors on the plant morphology in an intertidal salt marsh, Yellow River Delta, China

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Li, Shanze; Cui, Baoshan; Bai, Junhong; Xie, Tian; Yan, Jiaguo; Wang, Qing; Zhang, Shuyan

2018-02-01

Plant morphology plays important role in studying biogeography in many ecosystems. Suadea salsa, as a native plant community of northern China and an important habitat for diversity of waterbirds and macrobenthos, has often been overlooked. Nowadays, S. salsa community is facing great loss due to coastal reclamation activities and natural disturbances. To maintain and restore S. salsa community, it's important to address the plant morphology across marsh zones, as well as its relationships with local soil abiotic conditions. In our studied intertidal salt marsh, we found that less flood disturbance frequency, softer soil conditions, rich soil organic matter, total carbon and total nitrogen, lower water depth and water content, less species competition will benefit S. salsa plant in the morphology of high coverage, above-ground biomass, shoot height and leaf length. Lower soil porewater salinity will benefit the below-ground biomass of S. salsa. Thus, we recommend managers help alleviate soil abiotic stresses in the intertidal salt marshes, making the soil conditions more suitable for S. salsa growth and succession.

ThWRKY4 from Tamarix hispida Can Form Homodimers and Heterodimers and Is Involved in Abiotic Stress Responses.

Science.gov (United States)

Wang, Liuqiang; Zheng, Lei; Zhang, Chunrui; Wang, Yucheng; Lu, Mengzhu; Gao, Caiqiu

2015-11-13

WRKY proteins are a large family of transcription factors that are involved in diverse developmental processes and abiotic stress responses in plants. However, our knowledge of the regulatory mechanisms of WRKYs participation in protein-protein interactions is still fragmentary, and such protein-protein interactions are fundamental in understanding biological networks and the functions of proteins. In this study, we report that a WRKY protein from Tamarix hispida, ThWRKY4, can form both homodimers and heterodimers with ThWRKY2 and ThWRKY3. In addition, ThWRKY2 and ThWRKY3 can both bind to W-box motif with binding affinities similar to that of ThWRKY4. Further, the expression patterns of ThWRKY2 and ThWRKY3 are similar to that of ThWRKY4 when plants are exposed to abscisic acid (ABA). Subcellular localization shows that these three ThWRKY proteins are nuclear proteins. Taken together, these results demonstrate that ThWRKY4 is a dimeric protein that can form functional homodimers or heterodimers that are involved in abiotic stress responses.

Enhancement of Thiamin Content in Arabidopsis thaliana by Metabolic Engineering.

Science.gov (United States)

Dong, Wei; Stockwell, Virginia O; Goyer, Aymeric

2015-12-01

Thiamin is an essential nutrient in the human diet. Severe thiamin deficiency leads to beriberi, a lethal disease which is common in developing countries. Thiamin biofortification of staple food crops is a possible strategy to alleviate thiamin deficiency-related diseases. In plants, thiamin plays a role in the response to abiotic and biotic stresses, and data from the literature suggest that boosting thiamin content could increase resistance to stresses. Here, we tested an engineering strategy to increase thiamin content in Arabidopsis. Thiamin is composed of a thiazole ring linked to a pyrimidine ring by a methylene bridge. THI1 and THIC are the first committed steps in the synthesis of the thiazole and pyrimidine moieties, respectively. Arabidopsis plants were transformed with a vector containing the THI1-coding sequence under the control of a constitutive promoter. Total thiamin leaf content in THI1 plants was up approximately 2-fold compared with the wild type. THI1-overexpressing lines were then crossed with pre-existing THIC-overexpressing lines. Resulting THI1 × THIC plants accumulated up to 3.4- and 2.6-fold more total thiamin than wild-type plants in leaf and seeds, respectively. After inoculation with Pseudomonas syringae, THI1 × THIC plants had lower populations than the wild-type control. However, THI1 × THIC plants subjected to various abiotic stresses did not show any visible or biochemical changes compared with the wild type. We discuss the impact of engineering thiamin biosynthesis on the nutritional value of plants and their resistance to biotic and abiotic stresses. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Brassinosteroid Mediated Cell Wall Remodeling in Grasses under Abiotic Stress

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Xiaolan Rao

2017-05-01

Full Text Available Unlike animals, plants, being sessile, cannot escape from exposure to severe abiotic stresses such as extreme temperature and water deficit. The dynamic structure of plant cell wall enables them to undergo compensatory changes, as well as maintain physical strength, with changing environments. Plant hormones known as brassinosteroids (BRs play a key role in determining cell wall expansion during stress responses. Cell wall deposition differs between grasses (Poaceae and dicots. Grass species include many important food, fiber, and biofuel crops. In this article, we focus on recent advances in BR-regulated cell wall biosynthesis and remodeling in response to stresses, comparing our understanding of the mechanisms in grass species with those in the more studied dicots. A more comprehensive understanding of BR-mediated changes in cell wall integrity in grass species will benefit the development of genetic tools to improve crop productivity, fiber quality and plant biomass recalcitrance.

Plant survival in a changing environment: the role of nitric oxide in plant responses to abiotic stress

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Marcela eSimontacchi

2015-11-01

Full Text Available Nitric oxide in plants may originate endogenously or come from surrounding atmosphere and soil. Interestingly, this gaseous free radical is far from having a constant level and varies greatly among tissues depending on a given plant´s ontogeny and environmental fluctuations.Proper plant growth, vegetative development, and reproduction require the integration of plant hormonal activity with the antioxidant network, as well as the maintenance of concentration of reactive oxygen and nitrogen species within a narrow range. Plants are frequently faced with abiotic stress conditions such as low nutrient availability, salinity, drought, high ultraviolet (UV radiation and extreme temperatures, which can influence developmental processes and lead to growth restriction making adaptive responses the plant´s priority. The ability of plants to respond and survive under environmental-stress conditions involves sensing and signalling events where nitric oxide becomes a critical component mediating hormonal actions, interacting with reactive oxygen species, and modulating gene expression and protein activity. This review focuses on the current knowledge of the role of nitric oxide in adaptive plant responses to some specific abiotic stress conditions, particularly low mineral nutrient supply, drought, salinity and high UV-B radiation.

Plant Survival in a Changing Environment: The Role of Nitric Oxide in Plant Responses to Abiotic Stress

Science.gov (United States)

Simontacchi, Marcela; Galatro, Andrea; Ramos-Artuso, Facundo; Santa-María, Guillermo E.

2015-01-01

Nitric oxide in plants may originate endogenously or come from surrounding atmosphere and soil. Interestingly, this gaseous free radical is far from having a constant level and varies greatly among tissues depending on a given plant’s ontogeny and environmental fluctuations. Proper plant growth, vegetative development, and reproduction require the integration of plant hormonal activity with the antioxidant network, as well as the maintenance of concentration of reactive oxygen and nitrogen species within a narrow range. Plants are frequently faced with abiotic stress conditions such as low nutrient availability, salinity, drought, high ultraviolet (UV) radiation and extreme temperatures, which can influence developmental processes and lead to growth restriction making adaptive responses the plant’s priority. The ability of plants to respond and survive under environmental-stress conditions involves sensing and signaling events where nitric oxide becomes a critical component mediating hormonal actions, interacting with reactive oxygen species, and modulating gene expression and protein activity. This review focuses on the current knowledge of the role of nitric oxide in adaptive plant responses to some specific abiotic stress conditions, particularly low mineral nutrient supply, drought, salinity and high UV-B radiation. PMID:26617619

Phospholipid mediated activation of calcium dependent protein kinase 1 (CaCDPK1 from chickpea: a new paradigm of regulation.

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Ajay Kumar Dixit

Full Text Available Phospholipids, the major structural components of membranes, can also have functions in regulating signaling pathways in plants under biotic and abiotic stress. The effects of adding phospholipids on the activity of stress-induced calcium dependent protein kinase (CaCDPK1 from chickpea are reported here. Both autophosphorylation as well as phosphorylation of the added substrate were enhanced specifically by phosphatidylcholine and to a lesser extent by phosphatidic acid, but not by phosphatidylethanolamine. Diacylgylerol, the neutral lipid known to activate mammalian PKC, stimulated CaCDPK1 but at higher concentrations. Increase in V(max of the enzyme activity by these phospholipids significantly decreased the K(m indicating that phospholipids enhance the affinity towards its substrate. In the absence of calcium, addition of phospholipids had no effect on the negligible activity of the enzyme. Intrinsic fluorescence intensity of the CaCDPK1 protein was quenched on adding PA and PC. Higher binding affinity was found with PC (K(½ = 114 nM compared to PA (K(½ = 335 nM. We also found that the concentration of PA increased in chickpea plants under salt stress. The stimulation by PA and PC suggests regulation of CaCDPK1 by these phospholipids during stress response.

Fish mercury development in relation to abiotic characteristics and carbon sources in a six-year-old, Brazilian reservoir

Energy Technology Data Exchange (ETDEWEB)

Tuomola, Leena; Niklasson, Terese [Evolutionary Biology Centre and Department of Limnology, Uppsala University, Norbyvaegen 20, S-752 36 Uppsala (Sweden); Castro e Silva, Edinaldo de [Departamento de Quimica, Universidade Federal de Mato Grosso (UFMT), Av. Fernando C. Costa/sn, 78 090-900 Cuiaba-MT (Brazil); Hylander, Lars D. [Department of Earth Sciences, Air, Water and Landscape Science, Uppsala University, Villavaegen 16, S-752 36 Uppsala (Sweden)], E-mail: Lars.Hylander@hyd.uu.se

2008-02-01

Time series on fish mercury (Hg) development are rare for hydroelectric reservoirs in the tropics. In the central-western part of Brazil, a hydroelectric reservoir, called Lago Manso, was completed in 1999 after that background levels of fish Hg concentrations had been determined. The development for the first 3 years was studied in 2002. The objective of the present study was to determine development of fish Hg concentrations for a second three-year period after flooding. The bioaccumulation factor and certain abiotic and biotic factors, possibly affecting the availability and accumulation of Hg, were also examined. The results show that Hg levels in fish from Lago Manso have increased more than five times compared to the background levels observed before construction of the reservoir. At the same time, dissolved organic carbon has increased while dissolved oxygen has decreased indicating enhanced bioavailability of Hg. In the reservoir, Salminus brasiliensis had in average a Hg content of 1.1 {mu}g g{sup -1} f.w., Pseudoplatystoma fasciatum 1.2, Serrasalmus marginatus/spilopleura 0.9, and Brycon hilarii 0.6 {mu}g g{sup -1} f.w. The average fish Hg contents were higher downstream, except for B. hilarii. In the reservoir, the average Hg content of each species was in 2005 always over the consumption limit (0.55 {mu}g total Hg g{sup -1} f.w.) recommended by WHO. Therefore, the people living around Lago Manso should be informed of the health effects of Hg, and fish consumption recommendations should be carried out. The accumulation of Hg varies widely between species as shown by the bioaccumulation factor which ranges between 5.08 and 5.59 log units. The observed variation is explained by differences in diet and trophic position with piscivorous fish exhibiting the highest mean Hg concentration, followed by carnivorous and omnivorous species. Carbon isotope analyses imply that trophic position is not the only cause of the observed differences in Hg levels between

Expression Patterns and Identified Protein-Protein Interactions Suggest That Cassava CBL-CIPK Signal Networks Function in Responses to Abiotic Stresses.

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Mo, Chunyan; Wan, Shumin; Xia, Youquan; Ren, Ning; Zhou, Yang; Jiang, Xingyu

2018-01-01

Cassava is an energy crop that is tolerant of multiple abiotic stresses. It has been reported that the interaction between Calcineurin B-like (CBL) protein and CBL-interacting protein kinase (CIPK) is implicated in plant development and responses to various stresses. However, little is known about their functions in cassava. Herein, 8 CBL ( MeCBL ) and 26 CIPK ( MeCIPK ) genes were isolated from cassava by genome searching and cloning of cDNA sequences of Arabidopsis CBL s and CIPK s. Reverse-transcriptase polymerase chain reaction (RT-PCR) analysis showed that the expression levels of MeCBL and MeCIPK genes were different in different tissues throughout the life cycle. The expression patterns of 7 CBL and 26 CIPK genes in response to NaCl, PEG, heat and cold stresses were analyzed by quantitative real-time PCR (qRT-PCR), and it was found that the expression of each was induced by multiple stimuli. Furthermore, we found that many pairs of CBLs and CIPKs could interact with each other via investigating the interactions between 8 CBL and 25 CIPK proteins using a yeast two-hybrid system. Yeast cells co-transformed with cassava MeCIPK24, MeCBL10 , and Na + /H + antiporter MeSOS1 genes exhibited higher salt tolerance compared to those with one or two genes. These results suggest that the cassava CBL-CIPK signal network might play key roles in response to abiotic stresses.

Expression Patterns and Identified Protein-Protein Interactions Suggest That Cassava CBL-CIPK Signal Networks Function in Responses to Abiotic Stresses

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Chunyan Mo

2018-03-01

Full Text Available Cassava is an energy crop that is tolerant of multiple abiotic stresses. It has been reported that the interaction between Calcineurin B-like (CBL protein and CBL-interacting protein kinase (CIPK is implicated in plant development and responses to various stresses. However, little is known about their functions in cassava. Herein, 8 CBL (MeCBL and 26 CIPK (MeCIPK genes were isolated from cassava by genome searching and cloning of cDNA sequences of Arabidopsis CBLs and CIPKs. Reverse-transcriptase polymerase chain reaction (RT-PCR analysis showed that the expression levels of MeCBL and MeCIPK genes were different in different tissues throughout the life cycle. The expression patterns of 7 CBL and 26 CIPK genes in response to NaCl, PEG, heat and cold stresses were analyzed by quantitative real-time PCR (qRT-PCR, and it was found that the expression of each was induced by multiple stimuli. Furthermore, we found that many pairs of CBLs and CIPKs could interact with each other via investigating the interactions between 8 CBL and 25 CIPK proteins using a yeast two-hybrid system. Yeast cells co-transformed with cassava MeCIPK24, MeCBL10, and Na+/H+ antiporter MeSOS1 genes exhibited higher salt tolerance compared to those with one or two genes. These results suggest that the cassava CBL-CIPK signal network might play key roles in response to abiotic stresses.

Fe(II-III) Hydroxysalt Green Rusts; from Corrosion to Mineralogy and Abiotic to Biotic Reactions by Moessbauer Spectroscopy

International Nuclear Information System (INIS)

Genin, J.-M. R.

2004-01-01

Fe(II)-Fe(III) hydroxysalts commonly called green rusts are layered double hydroxides of formula [Fe II (1-x) Fe III x (OH) 2 ] x+ .[(x/n)A n- .(m/n)H 2 O] x- constituted of brucite-like layers containing Fe cations in the centres of OH - octahedrons and interlayers, which anions and water molecules belong to. They play a key role in corrosion and environmental sciences as well as mineralogy since they are, on the one hand, intermediate products between Fe(II) and Fe(III) states and, on the other hand, can be the major iron-bearing mineral in hydromorphic gley soils. Their crystal structure, Moessbauer spectra, methods of synthesis, abiotic as well as biotic, and some applications are presented here.

Comparative study of biogenic and abiotic iron-containing materials

Energy Technology Data Exchange (ETDEWEB)

Cherkezova-Zheleva, Z., E-mail: zzhel@ic.bas.bg; Shopska, M., E-mail: shopska@ic.bas.bg; Paneva, D. [Bulgarian Academy of Sciences, Institute of Catalysis (Bulgaria); Kovacheva, D. [Bulgarian Academy of Sciences, Institute of General and Inorganic Chemistry (Bulgaria); Kadinov, G.; Mitov, I. [Bulgarian Academy of Sciences, Institute of Catalysis (Bulgaria)

2016-12-15

Series of iron-based biogenic materials prepared by cultivation of Leptothrix group of bacteria in different feeding media (Sphaerotilus-Leptothrix group of bacteria isolation medium, Adler, Lieske and silicon-iron-glucose-peptone) were studied. Control samples were obtained in the same conditions and procedures but the nutrition media were not infected with bacteria, i.e. they were sterile. Room and low temperature Mössbauer spectroscopy, powder X-ray diffraction (XRD), and infrared spectroscopy (IRS) were used to reveal the composition and physicochemical properties of biomass and respective control samples. Comparative analysis showed differences in their composition and dispersity of present phases. Sample composition included different ratio of nanodimensional iron oxyhydroxide and oxide phases. Relaxation phenomena such as superparamagnetism or collective magnetic excitation behaviour were registered for some of them. The experimental data showed that the biogenic materials were enriched in oxyhydroxides of high dispersion. Catalytic behaviour of a selected biomass and abiotic material were studied in the reaction of CO oxidation. In situ diffuse-reflectance (DR) IRS was used to monitor the phase transformations in the biomass and CO conversion.

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

Science.gov (United States)

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

2016-04-01

How the abiotic factors represented by cold environment and biotic factors represented by livestock grazing will affect the vegetation structure of alpine grassland is a core issue in understanding the cause of biodiversity change on Tibetan Plateau. Past studies on changes of floristic composition, growth forms did not adequately answer question. Given the fact that the response of plant to environment change depend on its life strategy, a synthetical method that based on plant life strategy may deepen our understanding of the mechanism. Using Grime's concept of CSR plant classification, we carried out a vegetation survey along a gradient (three levels) of graze intensity on the south-east of Tibet Plateau, in order to evaluate the role and mechanism of abiotic stress and grazing disturbance in driving plant diversity change, by analyzing the plant life strategy compositions in each of the community and by comparing the characteristic of the strategy compositions along the graze gradient. When the graze intensity was relative low, the dominant plant life strategy gathered in the stress tolerance corner, which conformed the theory of environmental filter, indicating that the ideal top plant community may be dominated by the species with stress tolerant strategy. We also found that the response of strategy dominance to graze intensity increase is positively correlated with the competitive capacity (R 2=0.671; Pstrategy (R 2=0.047; P=0.42). This reflected a general shift of plant strategy from stress tolerant to competitive (rather than ruderal as expected) and suggested that the mechanism of graze to affect plant community is different from that of other disturbance like fire, clipping, till, etc. The particular selective foraging and escaping from feces may provide more opportunities for competitive than ruderal strategy to dominant the community. This study demonstrated that CSR plant strategy be a useful tool to evaluate the effects of abiotic and biotic factors

Development of a Model of Geophysical and Geochemical Controls on Abiotic Carbon Cycling on Earth-Like Planets

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Neveu, M.; Felton, R.; Domagal-Goldman, S. D.; Desch, S. J.; Arney, G. N.

2017-12-01

About 20 Earth-sized planets (0.6-1.6 Earth masses and radii) have now been discovered beyond our solar system [1]. Although such planets are prime targets in the upcoming search for atmospheric biosignatures, their composition, geology, and climate are essentially unconstrained. Yet, developing an understanding of how these factors influence planetary evolution through time and space is essential to establishing abiotic backgrounds against which any deviations can provide evidence for biological activity. To this end, we are building coupled geophysical-geochemical models of abiotic carbon cycling on such planets. Our models are controlled by atmospheric factors such as temperature and composition, and compute interior inputs to atmospheric species. They account for crustal weathering, ocean-atmosphere equilibria, and exchange with the deep interior as a function of planet composition and size (and, eventually, age).Planets in other solar systems differ from the Earth not only in their bulk physical properties, but also likely in their bulk chemical composition [2], which influences key parameters such as the vigor of mantle convection and the near-surface redox state. Therefore, simulating how variations in such parameters affect carbon cycling requires us to simulate the above processes from first principles, rather than by using arbitrary parameterizations derived from observations as is often done with models of carbon cycling on Earth [3] or extrapolations thereof [4]. As a first step, we have developed a kinetic model of crustal weathering using the PHREEQC code [5] and kinetic data from [6]. We will present the ability of such a model to replicate Earth's carbon cycle using, for the time being, parameterizations for surface-interior-atmosphere exchange processes such as volcanism (e.g., [7]).[1] exoplanet.eu, 7/28/2017.[2] Young et al. (2014) Astrobiology 14, 603-626.[3] Lerman & Wu (2008) Kinetics of Global Geochemical Cycles. In Kinetics of Water

Screening and Validation of Housekeeping Genes of the Root and Cotyledon of Cunninghamia lanceolata under Abiotic Stresses by Using Quantitative Real-Time PCR

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Wenlong Bao

2016-07-01

Full Text Available Cunninghamia lanceolata (Chinese fir is a fast-growing and commercially important conifer of the Cupressaceae family. Due to the unavailability of complete genome sequences and relatively poor genetic background information of the Chinese fir, it is necessary to identify and analyze the expression levels of suitable housekeeping genes (HKGs as internal reference for precise analysis. Based on the results of database analysis and transcriptome sequencing, we have chosen five candidate HKGs (Actin, GAPDH, EF1a, 18S rRNA, and UBQ with conservative sequences in the Chinese fir and related species for quantitative analysis. The expression levels of these HKGs in roots and cotyledons under five different abiotic stresses in different time intervals were measured by qRT-PCR. The data were statistically analyzed using the following algorithms: NormFinder, BestKeeper, and geNorm. Finally, RankAggreg was applied to merge the sequences generated from three programs and rank these according to consensus sequences. The expression levels of these HKGs showed variable stabilities under different abiotic stresses. Among these, Actin was the most stable internal control in root, and GAPDH was the most stable housekeeping gene in cotyledon. We have also described an experimental procedure for selecting HKGs based on the de novo sequencing database of other non-model plants.

Quantifying Components of Soil Respiration and Their Response to Abiotic Factors in Two Typical Subtropical Forest Stands, Southwest China

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Yu, Lei; Wang, Yujie; Wang, Yunqi; Sun, Suqi; Liu, Liziyuan

2015-01-01

Separating the components of soil respiration and understanding the roles of abiotic factors at a temporal scale among different forest types are critical issues in forest ecosystem carbon cycling. This study quantified the proportions of autotrophic (R A) and heterotrophic (R H) in total soil (R T) respiration using trenching and litter removal. Field studies were conducted in two typical subtropical forest stands (broadleaf and needle leaf mixed forest; bamboo forest) at Jinyun Mountain, near the Three Georges Reservoir in southwest China, during the growing season (Apr.–Sep.) from 2010 to 2012. The effects of air temperature (AT), soil temperature (ST) and soil moisture (SM) at 6cm depth, solar radiation (SR), pH on components of soil respiration were analyzed. Results show that: 1) SR, AT, and ST exhibited a similar temporal trend. The observed abiotic factors showed slight interannual variability for the two forest stands. 2) The contributions of R H and R A to R T for broadleaf and needle leaf mixed forest were 73.25% and 26.75%, respectively, while those for bamboo forest were 89.02% and 10.98%, respectively; soil respiration peaked from June to July. In both stands, CO2 released from the decomposition of soil organic matter (SOM), the strongest contributor to R T, accounted for over 63% of R H. 3) AT and ST were significantly positively correlated with R T and its components (psoil respiration. 4) Components of soil respiration were significantly different between two forest stands (psoil respiration and its components. PMID:25680112