Regulation Of Abiotic Stress Responses Research Articles

Identification of the LOX Gene Family in Peanut and Functional Characterization of AhLOX29 in Drought Tolerance.

Lipoxygenases (LOXs) are a gene family of nonheme iron-containing dioxygenases that play important roles in plant development and defense responses. To date, a comprehensive analysis of LOX genes and their biological functions in response to abiotic stresses in peanut has not been performed. In this study, a total of 72 putative LOX genes were identified in cultivated (Arachis hypogaea) and wild-type peanut (Arachis duranensis and Arachis ipaensis) and classified into three subfamilies: 9-LOX, type I 13-LOX and type II 13-LOX. The gene structures and protein motifs of these peanut LOX genes were highly conserved among most LOXs. We found that the chromosomal distribution of peanut LOXs was not random and that gene duplication played a crucial role in the expansion of the LOX gene family. Cis-acting elements related to development, hormones, and biotic and abiotic stresses were identified in the promoters of peanut LOX genes. The expression patterns of peanut LOX genes were tissue-specific and stress-inducible. Quantitative real-time PCR results further confirmed that peanut LOX gene expression could be induced by drought, salt, methyl jasmonate and abscisic acid treatments, and these genes exhibited diverse expression patterns. Furthermore, overexpression of AhLOX29 in Arabidopsis enhanced the resistance to drought stress. Compared with wide-type, AhLOX29-overexpressing plants showed significantly decreased malondialdehyde contents, as well as increased chlorophyll degradation, proline accumulation and superoxide dismutase activity, suggesting that the transgenic plants exhibit strengthened capacity to scavenge reactive oxygen species and prevent membrane damage. This systematic study provides valuable information about the functional characteristics of AhLOXs in the regulation of abiotic stress responses of peanut.

Biological Parts for Engineering Abiotic Stress Tolerance in Plants.

It is vital to ramp up crop production dramatically by 2050 due to the increasing global population and demand for food. However, with the climate change projections showing that droughts and heatwaves becoming common in much of the globe, there is a severe threat of a sharp decline in crop yields. Thus, developing crop varieties with inbuilt genetic tolerance to environmental stresses is urgently needed. Selective breeding based on genetic diversity is not keeping up with the growing demand for food and feed. However, the emergence of contemporary plant genetic engineering, genome-editing, and synthetic biology offer precise tools for developing crops that can sustain productivity under stress conditions. Here, we summarize the systems biology-level understanding of regulatory pathways involved in perception, signalling, and protective processes activated in response to unfavourable environmental conditions. The potential role of noncoding RNAs in the regulation of abiotic stress responses has also been highlighted. Further, examples of imparting abiotic stress tolerance by genetic engineering are discussed. Additionally, we provide perspectives on the rational design of abiotic stress tolerance through synthetic biology and list various bioparts that can be used to design synthetic gene circuits whose stress-protective functions can be switched on/off in response to environmental cues.

Transcriptome of weeping pinyon pine, Pinus pinceana, shows differences across heterogeneous habitats

We reconstructed the needle tissue Transcriptome of P. pinceana for individuals from distinct biogeographic regions across a temperature and precipitation gradient that represents its natural distribution. Gene expression analysis via RNA-Seq identified differential response to biotic stress. Phenotypic plasticity includes physiological traits affected by subtle changes in mRNA expression levels, causing different molecular phenotypes. We assessed the differential response to climate heterogeneity across the geographic range of Pinus pinceana G. Gordon & Glendinning. This pinyon pine shows a fragmented geographic distribution suggesting adaptation to the arid and extreme conditions of the eastern mountain slopes of the Chihuahuan desert. The geographic distribution of P. pinceana spans regions with significant variation in annual temperature and precipitation. We tested whether phenotypic divergence is supported by differences in expression profiles in P. pinceana mature trees along its natural distribution and corresponds to the changes in drought and other environmental stress. The reconstructed Transcriptome included 45,431 high-quality annotations derived from the needles of seven individuals across contrasting biogeographic and climatic localities. Trees from the driest regions shared active responses related to abiotic factors. The differential expression analysis identified intermediates and regulators of abiotic stress response for 26 genes, highlighting families involved in the environmental response to abiotic stress, and proteins linked to up-regulated responses, such as LRR receptor-like serine/threonine-protein kinase and L-type lectin receptor kinases (LecRK), directly related to pathogens. When Chihuahuan desert samples were compared with arboretum samples, we found differential expression of a regulator of root morphogenesis, cysteine-rich receptor-like protein kinase (CRK28), which could relate to differential absorption in drought conditions.

MdDREB2A in apple is involved in the regulation of multiple abiotic stress responses

Abiotic stress has a serious effect on plant growth. The transcription factor DREB2A is a member of the AP2/ERF family, which is widely involved in abiotic stress response. However, the function of apple MdDREB2A has not been systematically investigated. In this study,MdDREB2A was isolated from the cultivar ‘Royal Gala’. The open reading frame of MdDREB2A was 1 197 bp in length and it encoded a protein of 398 amino acids with molecular weight of 43.8 kD. As a transcription factor, MdDREB2A was located in the nucleus. qRT-PCR analysis showed that MdDREB2A was involved in responses to drought, salt, and ABA stresses. Under these stress treatments, the relative electrical conductivity, superoxide anion and malondialdehyde (MDA) in transgenic materials significantly decreased, and the content of proline increased in MdDREB2A transgenic plants, compared to the controls, indicating that MdDREB2A transgenic apple calli and transgenic Arabidopsis exhibited improved resistance to abiotic stress. This study introduces a candidate gene for the genetic improvement of crop resistance and reveals important function of MdDREB2A in the regulation of abiotic stress response.

OsCBE1, a Substrate Receptor of Cullin4-Based E3 Ubiquitin Ligase, Functions as a Regulator of Abiotic Stress Response and Productivity in Rice

Ubiquitination is an important environmental stress response, and E3 ubiquitin ligases play a major role in the process. T-DNA insertion mutants of rice, Oscbe1-1, and Oscbe1-2, were identified through the screening of cold stress tolerance at seedling stage. Oscbe1 mutants showed a significantly higher cold stress tolerance in the fresh weight, chlorophyll content, and photosynthetic efficiency than wild type. Molecular prediction showed that OsCBE1 (Oryza sativa Cullin4-Based E3 ubiquitin ligase1) encoded a novel substrate receptor of Cullin4-based E3 ubiquitin ligase complex (C4E3). Whereas Oscbe1 mutants had fewer panicles and grains than wild type in the paddy field, the overexpression lines of OsCBE1 had more panicles and grains, suggesting that OsCBE1 is involved in the regulation of both abiotic stress response and development. Oscbe1 mutants also showed ABA hypersensitivity during seed germination, suggesting OsCBE1 function for the stress response via ABA signaling. In silico analysis of OsCBE1 activity predicted a CCCH-type transcription factor, OsC3H32, as a putative substrate. Co-IP (Co-immunoprecipitation) study showed that OsCBE1 interacts with OsDDB1, an expected binding component of OsCBE1 and OsC3H32. Additionally, expression of OsOLE16, OsOLE18, and OsBURP5 were negatively related with expression of OsCBE1. These results suggest that OsCBE1 functions as a regulator of the abiotic stress response via CCCH as a member of the C4E3.

Plant Non-Coding RNAs: Origin, Biogenesis, Mode of Action and Their Roles in Abiotic Stress.

As sessile species, plants have to deal with the rapidly changing environment. In response to these environmental conditions, plants employ a plethora of response mechanisms that provide broad phenotypic plasticity to allow the fine-tuning of the external cues related reactions. Molecular biology has been transformed by the major breakthroughs in high-throughput transcriptome sequencing and expression analysis using next-generation sequencing (NGS) technologies. These innovations have provided substantial progress in the identification of genomic regions as well as underlying basis influencing transcriptional and post-transcriptional regulation of abiotic stress response. Non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs), short interfering RNAs (siRNAs), and long non-coding RNAs (lncRNAs), have emerged as essential regulators of plants abiotic stress response. However, shared traits in the biogenesis of ncRNAs and the coordinated cross-talk among ncRNAs mechanisms contribute to the complexity of these molecules and might play an essential part in regulating stress responses. Herein, we highlight the current knowledge of plant microRNAs, siRNAs, and lncRNAs, focusing on their origin, biogenesis, modes of action, and fundamental roles in plant response to abiotic stresses.

The banana (Musa acuminata) MYB gene family and MaMYB14, MaMYB63 and MaMYB110 expression in response to salinity-stress in cv. Berangan

MYB transcription factors are among important regulators of abiotic stress responses, including response to the major agricultural constraint of increased salinity. To determine MYB gene family members associated with stress in the major starch crop banana (Musa acuminata Colla) a genome-wide analysis was made. A non-redundant set of 154 MYB genes (MaMYB) is predicted to encode proteins with variable lengths mostly localised in the nucleus. Based on the conserved repeats, MaMYB fall into subfamilies R1-MYB, R2R3-MYB and R1R2R3-MYB, with the majority (80.5%) in the R2R3-MYB subfamily. Ontology prediction indicates the involvement of MaMYB in the regulation of plant development, metabolism, cellular and various stress responses. MaMYB genes show ubiquitous distribution among the 11 banana chromosomes with the highest density in chromosome 9 (11.04%). The chromosomal distribution pattern strongly indicates that dispersed duplication mainly contributed to the expansion within the MaMYB gene family in the banana. Phylogenetic analysis identified three R2R3-MaMYB gene candidates with high similarity to salt responsive orthologues from other species. Quantitative RT-PCR analysis showed MaMYB14, MaMYB63 and MaMYB110 to have significantly increased expression in the roots of banana plants exposed to salt stress.

Role of Epichloë Endophytes in Improving Host Grass Resistance Ability and Soil Properties.

The past decade has witnessed significant advances in understanding the interaction between grasses and systemic fungal endophytes of the genus Epichloë, with evidence that plants have evolved multiple strategies to cope with abiotic stresses by reprogramming physiological responses. Soil nutrients directly affect plant growth, while soil microbes are also closely connected to plant growth and health. Epichloë endophytes could affect soil fertility by modifying soil nutrient contents and soil microbial diversity. Therefore, we analyze recent advances in our understanding of the role of Epichloë endophytes under the various abiotic stresses and the role of grass-Epichloë symbiosis on soil fertility. Various cool-season grasses are infected by Epichloë species, which contribute to health, growth, persistence, and seed survival of host grasses by regulating key systems, including photosynthesis, osmotic regulation, and antioxidants and activity of key enzymes of host physiology processes under abiotic stresses. The Epichloë endophyte offers significant prospects to magnify the crop yield, plant resistance, and food safety in ecological systems by modulating soil physiochemical properties and soil microbes. The enhancing resistance of host grasses to abiotic stresses by an Epichloë endophyte is a complex manifestation of different physiological and biochemical events through regulating soil properties and soil microbes by the fungal endophyte. The Epichloë-mediated mechanisms underlying regulation of abiotic stress responses are involved in osmotic adjustment, antioxidant machinery, photosynthetic system, and activity of key enzymes critical in developing plant adaptation strategies to abiotic stress. Therefore, the Epichloë endophytes are an attractive choice in increasing resistance of plants to abiotic stresses and are also a good candidate for improving soil fertility and regulating microbial diversity to improve plant growth.

C2H2 Zinc Finger Proteins: Master Regulators of Abiotic Stress Responses in Plants.

Abiotic stresses such as drought and salinity are major environmental factors that limit crop yields. Unraveling the molecular mechanisms underlying abiotic stress resistance is crucial for improving crop performance and increasing productivity under adverse environmental conditions. Zinc finger proteins, comprising one of the largest transcription factor families, are known for their finger-like structure and their ability to bind Zn2+. Zinc finger proteins are categorized into nine subfamilies based on their conserved Cys and His motifs, including the Cys2/His2-type (C2H2), C3H, C3HC4, C2HC5, C4HC3, C2HC, C4, C6, and C8 subfamilies. Over the past two decades, much progress has been made in understanding the roles of C2H2 zinc finger proteins in plant growth, development, and stress signal transduction. In this review, we focus on recent progress in elucidating the structures, functions, and classifications of plant C2H2 zinc finger proteins and their roles in abiotic stress responses.

OsFKBP20-1b interacts with the splicing factor OsSR45 and participates in the environmental stress response at the post-transcriptional level in rice.

Sessile plants have evolved distinct mechanisms to respond and adapt to adverse environmental conditions through diverse mechanisms including RNA processing. While the role of RNA processing in the stress response is well understood for Arabidopsis thaliana, limited information is available for rice (Oryza sativa). Here, we show that OsFKBP20-1b, belonging to the immunophilin family, interacts with the splicing factor OsSR45 in both nuclear speckles and cytoplasmic foci, and plays an essential role in post-transcriptional regulation of abiotic stress response. The expression of OsFKBP20-1b was highly upregulated under various abiotic stresses. Moreover genetic analysis revealed that OsFKBP20-1b positively affected transcription and pre-mRNA splicing of stress-responsive genes under abiotic stress conditions. In osfkbp20-1b loss-of-function mutants, the expression of stress-responsive genes was downregulated, while that of their splicing variants was increased. Conversely, in plants overexpressing OsFKBP20-1b, the expression of the same stress-responsive genes was strikingly upregulated under abiotic stress. In vivo experiments demonstrated that OsFKBP20-1b directly maintains protein stability of OsSR45 splicing factor. Furthermore, we found that the plant-specific OsFKBP20-1b gene has uniquely evolved as a paralogue only in some Poaceae species. Together, our findings suggest that OsFKBP20-1b-mediated RNA processing contributes to stress adaptation in rice.

TaPP2AbBʺ-γ, a wheat regulatory subunit of PP2A enhanced abiotic stress tolerance

Protein dephosphorylation mediated by serine/threonine protein phosphatase 2A (PP2A) plays critical roles in regulation of abiotic stress responses in plants. Here, we report the involvement of a B″ regulatory subunit of PP2A in wheat (Triticum aestivum L.), TaPP2AbB″-γ, in the positive regulation of stress responses. The transcript of TaPP2AbB″-γ was induced in roots of wheat seedlings by salinity, drought, cold stresses and exogenous ABA application. Overexpression of TaPP2AbB″-γ enhanced the tolerance to various environmental stresses in transgenic Arabidopsis seedlings. Yeast two-hybrid assay demonstrated that TaPP2AbB″-γ interact with the first 100 amino acids of TaBZR1, a positive regulator of Brassinosteroids (BRs) signaling. The expression of TaBZR1 gene was up-regulated in roots upon exposure to NaCl stress. All our results suggested that TaPP2AbB″-γ functions in improving abiotic stress tolerance by directly binding to TaBZR1, pointing to a possible cross-talk of BR signaling with TaPP2AbB″-γ mediated stress response.

Genome-wide identification and expression analysis of HSP90 gene family in Nicotiana tabacum

BackgroundHeat shock proteins 90 (HSP90s) are a highly conserved protein family of cellular chaperones widely found in plants; they play a fundamental role in response to biotic and abiotic stresses. The genome-wide analysis of HSP90 gene family has been completed for some species; however, it has been rarely reported for the tobacco HSP90 genes.ResultsIn this study, we systematically conducted genome-wide identification and expression analysis of the tobacco HSP90 gene family, including gene structures, evolutionary relationships, chromosomal locations, conserved domains, and expression patterns. Twenty-one NtHSP90s were identified and classified into eleven categories (NtHSP90–1 to NtHSP90–11) based on phylogenetic analysis. The conserved structures and motifs of NtHSP90 proteins in the same subfamily were highly consistent. Most NtHSP90 proteins contained the ATPase domain, which was closely related to conserved motif 2. Motif 5 was a low complexity sequence and had the function of signal peptide. At least 6 pairs of NtHSP90 genes underwent gene duplication, which arose from segment duplication and tandem duplication events. Phylogenetic analysis showed that most species expanded according to their own species-specific approach during the evolution of HSP90s. Dynamic expression analysis indicated that some NtHSP90 genes may play fundamental roles in regulation of abiotic stress response. The expression of NtHSP90–4, NtHSP90–5, and NtHSP90–9 were up-regulated, while NtHSP90–6, and NtHSP90–7 were not induced by ABA, drought, salt, cold and heat stresses. Among the five treatments, NtHSP90s were most strongly induced by heat stress, and weakly activated by ABA treatment. There was a similar response pattern of NtHSP90s under osmotic stress, or extreme temperature stress.ConclusionsThis is the first genome-wide analysis of Hsp90 in N. tabacum. These results indicate that each NtHSP90 member fulfilled distinct functions in response to various abiotic stresses.

Overexpression of Cotton a DTX/MATE Gene Enhances Drought, Salt, and Cold Stress Tolerance in Transgenic Arabidopsis.

Abiotic stresses have negative effects on plants growth and development. Plants, being sessile, have developed specific adaptive strategies that allow them to rapidly detect and respond to abiotic stress factors. The detoxification efflux carriers (DTX)/multidrug and toxic compound extrusion (MATE) transporters are of significance in the translocation of abscisic acid (ABA), a phytohormone with profound role in plants under various abiotic stress conditions. The ABA signaling cascades are the core regulators of abiotic stress responses in plants, triggering major changes in gene expression and adaptive physiological responses. We therefore carried out genome-wide analysis of the DTX/MATE gene family, transformed a DTX/MATE gene in Arabidopsis and carried out functional analysis under drought, salt, and cold stress conditions. We identified 128, 70, and 72 DTX/MATE genes in Gossypium hirsutum, Gossypium arboreum, and Gossypium raimondii, respectively. The proteins encoded by the DTX/MATE genes showed varied physiochemical properties but they all were hydrophobic. The Gh_D06G0281 (DTX/MATE) over-expressing Arabidopsis lines were highly tolerant under drought, salt, and cold stress with high production of antioxidant enzymes and significantly reduced levels of oxidants. Lipid peroxidation, as measured by the level of malondialdehyde concentrations was relatively low in transgenic lines compared to wild types, an indication of reduced oxidative stress levels in the transgenic plants. Based on physiological measurements, the transgenic plants exhibited significantly higher relative leaf water content, reduced excised leaf water loss and a significant reduction in ion leakage as a measure of the cell membrane stability compared to the wild types. Abiotic stress responsive genes, ABF4, CBL1, SOS1, and RD29B were highly expressed in the transgenic lines compared to the non-transformed wild type plants. The protein encoded by the Gh_D06G0281 (DTX/MATE) gene was predicted to be located within the plasma membrane. Since signals from extracellular stimuli are transmitted through the plasma membrane most of which are conducted by plasma membrane proteins it is possible the Gh_D06G0281 (DTX/MATE) gene product could be important for this process.

OsPUB75, an Armadillo/U-box protein interacts with GSK3 kinase and functions as negative regulator of abiotic stress responses

It has become increasingly evident that the protein degradation mediated by E3 ligases is a crucial cellular process that regulates both biotic and abiotic stresses in plants. Previously, we have reported the microarray expression analysis of ARM/U-box proteins during abiotic stress conditions. In this study, we have performed a detailed functional analysis of OsPUB75/ARM, which is transcriptionally repressed during stress conditions. OsPUB75/ARM is a cytosolic RING-type E3 ubiquitin (Ub) ligase that negatively regulates drought and salinity induced osmotic stress response in Arabidopsis. The phenotypic analysis of OsPUB75/ARM-OE showed inhibition of growth due to enhanced ROS production during salinity and mannitol induced oxidative stress conditions. Yeast two-hybrid screening using OsPUB75/ARM as bait identified OsSK41 (Shaggy-like kinase 41) as its target, which belongs to the Glycogen Synthase kinase 3 (GSK3) family. A specific interaction between OsPUB75/ARM and OsSK41 and auto-ubiquitination activity of OsPUB75/ARM were demonstrated in planta and in vitro. The subcellular localization and protein interaction by BiFC assay in Nicotiana benthamiana showed that OsPUB75/ARM and OsSK41 co-localize to the cytosolic spherical body, which lies in close proximity to the plasma membrane. The sensitivity of OsPUB75/ARM-OE lines on stress media indicates that this protein might be involved in the negative regulation of antioxidant system, which sets the redox-status of the cell upon activation by OsSK41. Collectively, our results suggest that OsPUB75/ARM is an important negative regulator of abiotic stress responses in Arabidopsis.

Enhanced tolerance to a combination of heat stress and drought in Arabidopsis plants deficient in ICS1 is associated with modulation of photosynthetic reaction center proteins.

Plants are exposed to multiple abiotic stresses that simultaneously occur under natural environmental conditions. Studies deciphering acclimation of plants to stress combinations are, however, still scarce. ISOCHORISMATE SYNTHASE 1 (ICS1) is known as a crucial enzyme required for synthesis of salicylic acid and phylloquinone, one of the components of the photosystem I complex. Although the significance of ICS1 in the regulation of abiotic stress response and pathogen defense in plants has been evidenced in previous studies, the role of this enzyme in the acclimation of plants to stress combinations is still largely unknown. In this study, we demonstrated the enhanced tolerance of Arabidopsis salicylic acid induction deficient 2-1(sid2-1) mutant deficient in ICS1 to a combination of heat stress and drought. H2 O2 -dependent stomatal closure and accumulation of total soluble sugars are associated with the enhanced tolerance of sid2-1 plants to this stress combination. In addition, sid2-1 plants showed higher accumulation of reaction center proteins (D1 and D2) in photosystem II accompanied by enhanced expression of transcripts involved in repair of these reaction center proteins. Furthermore, investigation of chlorophyll fluorescence indicated that mechanisms for dissipating the excess energy might be activated in sid2-1 plants specifically under a combination of heat stress and drought. Taken together, our findings suggest that maintenance of photosynthetic apparatus as well as prevention of excess water loss might enhance the tolerance of sid2-1 plants deficient in ICS1 to a combination of heat stress and drought.

A multifaceted rhizobacterium Bacillus licheniformis functions as a fungal antagonist and a promoter of plant growth and abiotic stress tolerance

Plant-growth-promoting rhizobacteria play a beneficial role in plant growth through various mechanisms. In this study, an isolated rhizobacterial strain, Bacillus licheniformis CH102 (hereafter CH102), exhibited antifungal activity and harbored genes required for lantibiotic and 2,3-butanediol production. In Arabidopsis, increased root hair number and fresh weight were obtained in the CH102-inoculated seedlings. Moreover, increases in chlorophyll content, H2O2 concentration and activities of antioxidant enzymes including catalase and POD were observed in the treated seedlings. Exposure to CH102 increased the tolerance toward high temperatures and water deficits in Arabidopsis seedlings. CH102 induced gene expression involved in induced disease resistance, nitrogen assimilation, antioxidants, photosystem II, ion transport and synthesis of secondary metabolites. Arabidopsis transcriptomic analysis revealed the CH102-upregulated genes were associated with several cellular pathways including the PEP-PEPR system, cell wall modification, and biosynthesis of osmoprotectants including choline, proline, and galactinol. The presence of CH102 elicited increased response of Arabidopsis genes associated with the jasmonic acid (JA) and abscisic acid (ABA) signaling pathways. Moreover, the upregulated expression of SLAC1 HOMOLOGUE 3 (SLAH3) function in the regulation of stomatal closure was detected. Furthermore, CH102 inoculation increased expression of transcription factors implicated in the regulation of abiotic stress responses, including DDF2, CBF1, DREB2A, HSFA2, WRKY30 and WRKY33. In summary, CH102 exerts effects on multiple cellular pathways involved in defense response, metabolism, antioxidant system and hormone signaling such as JA and ABA to regulate plant growth and tolerance to heat and drought stress.

Expression profiles of genes regulated by BplMYB46 in Betula platyphylla

The transcription factor BplMYB46 has been identified as a regulator of abiotic stress responses and promoter of secondary wall deposition in Betula platyphylla. To investigate the downstream targets of BplMYB46, the expression profiles of genes in stems from BplMYB46-overexpressing (OE) and BplMYB46-silencing (SE) plants were studied. In OE stems, 952 genes were upregulated, and 1469 were downregulated in comparison to SE stems. In a KEGG pathway enrichment analysis of differentially expressed genes (DEGs), 1387 differentially expressed genes were annotated for 117 metabolic pathways. DEGs were abundant for metabolic pathway, secondary metabolite biosynthesis, plant hormone signal transduction, phenylpropanoid and flavonoid biosynthesis. DEGs were implicated lignin or cellulose biosynthesis, cell wall modification, xylem development, disease resistance, stress responses, and anthocyanin biosynthesis. These results suggested that BplMYB46 regulates cell wall development and stress resistance by affecting the expression of these genes. Our study further elucidates the mechanism by which BplMYB46 mediates abiotic stress responses and secondary cell wall biosynthesis in birch.

Regulation of abiotic stress responses by peptides in long-distance signaling

Regulation of abiotic stress responses by peptides in long-distance signaling

Plant Responses to Abiotic Stress Regulated by Histone Deacetylases.

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.

Multilevel Regulation of Abiotic Stress Responses in Plants.

The sessile lifestyle of plants requires them to cope with stresses in situ. Plants overcome abiotic stresses by altering structure/morphology, and in some extreme conditions, by compressing the life cycle to survive the stresses in the form of seeds. Genetic and molecular studies have uncovered complex regulatory processes that coordinate stress adaptation and tolerance in plants, which are integrated at various levels. Investigating natural variation in stress responses has provided important insights into the evolutionary processes that shape the integrated regulation of adaptation and tolerance. This review primarily focuses on the current understanding of how transcriptional, post-transcriptional, post-translational, and epigenetic processes along with genetic variation orchestrate stress responses in plants. We also discuss the current and future development of computational tools to identify biologically meaningful factors from high dimensional, genome-scale data and construct the signaling networks consisting of these components.