Combinatorial interactions of multiple cis-elements regulating the induction of the Arabidopsis XERO2 dehydrin gene by abscisic acid and cold

Transcriptome Analysis of Eggplant under Salt Stress: AP2/ERF Transcription Factor SmERF1 Acts as a Positive Regulator of Salt Stress

Salt stress, a type of abiotic stress, impedes plant growth and development and strongly reduces crop yield. The molecular mechanisms underlying plant responses to salt stress remain largely unclear. To characterize the enriched pathways and genes that were affected during salt treatment, we performed mRNA sequencing (mRNA-seq) in eggplant roots and identified 8509 differentially expressed genes (DEGs) between the mock and 24 h under salt stress. Among these DEGs, we found that the AP2/ERF transcription factor family member SmERF1 belongs to the plant-pathogen interaction pathway, which was significantly upregulated by salt stress. We found that SmERF1 localizes in the nuclei with transcriptional activity. The results of the virus-induced gene silencing assay showed that SmERF1 silencing markedly enhanced the susceptibility of plants to salt stress, significantly downregulated the transcript expression levels of salt stress defense-related marker genes (9-cis-epoxycarotenoid dioxygenase [SmNCED1, SmNCED2], Dehydrin [SmDHN1], and Dehydrin (SmDHNX1), and reduced the activity of superoxide dismutase and catalase. Silencing SmERF1 promoted the generation of H₂O₂ and proline. In addition, the transient overexpression of SmERF1 triggered intense cell death in eggplant leaves, as assessed by the darker diaminobenzidine and trypan blue staining. These findings suggest that SmERF1 acts as a positive regulator of eggplant response to salt stress. Hence, our results suggest that AP2/ERF transcription factors play a vital role in the response to salt stress.

The AC2 Protein of a Bipartite Geminivirus Stimulates the Transcription of the BV1 Gene through Abscisic Acid Responsive Promoter Elements

Geminiviruses possess single-stranded, circular DNA genomes and control the transcription of their late genes, including BV1 of many bipartite begomoviruses, through transcriptional activation by the early expressing AC2 protein. DNA binding by AC2 is not sequence-specific; hence, the specificity of AC2 activation is thought to be conferred by plant transcription factors (TFs) recruited by AC2 in infected cells. However, the exact TFs AC2 recruits are not known for most viruses. Here, we report a systematic examination of the BV1 promoter (P_BV1) of the mungbean yellow mosaic virus (MYMV) for conserved promoter motifs. We found that MYMV P_BV1 contains three abscisic acid (ABA)-responsive elements (ABREs) within its first 70 nucleotides. Deleting these ABREs, or mutating them all via site-directed mutagenesis, abolished the capacity of P_BV1 to respond to AC2-mediated transcriptional activation. Furthermore, ABRE and other related ABA-responsive elements were prevalent in more than a dozen Old World begomoviruses we inspected. Together, these findings suggest that ABA-responsive TFs may be recruited by AC2 to BV1 promoters of these viruses to confer specificity to AC2 activation. These observations are expected to guide the search for the actual TF(s), furthering our understanding of the mechanisms of AC2 action.

PropaNet: Time-Varying Condition-Specific Transcriptional Network Construction by Network Propagation

Transcription factor (TF) has a significant influence on the state of a cell by regulating multiple down-stream genes. Thus, experimental and computational biologists have made great efforts to construct TF gene networks for regulatory interactions between TFs and their target genes. Now, an important research question is how to utilize TF networks to investigate the response of a plant to stress at the transcription control level using time-series transcriptome data. In this article, we present a new computational network, PropaNet, to investigate dynamics of TF networks from time-series transcriptome data using two state-of-the-art network analysis techniques, influence maximization and network propagation. PropaNet uses the influence maximization technique to produce a ranked list of TFs, in the order of TF that explains differentially expressed genes (DEGs) better at each time point. Then, a network propagation technique is used to select a group of TFs that explains DEGs best as a whole. For the analysis of Arabidopsis time series datasets from AtGenExpress, we used PlantRegMap as a template TF network and performed PropaNet analysis to investigate transcriptional dynamics of Arabidopsis under cold and heat stress. The time varying TF networks showed that Arabidopsis responded to cold and heat stress quite differently. For cold stress, bHLH and bZIP type TFs were the first responding TFs and the cold signal influenced histone variants, various genes involved in cell architecture, osmosis and restructuring of cells. However, the consequences of plants under heat stress were up-regulation of genes related to accelerating differentiation and starting re-differentiation. In terms of energy metabolism, plants under heat stress show elevated metabolic process and resulting in an exhausted status. We believe that PropaNet will be useful for the construction of condition-specific time-varying TF network for time-series data analysis in response to stress. PropaNet is available at http://biohealth.snu.ac.kr/software/PropaNet.

Regulation of low temperature stress in plants by microRNAs

Low temperature is one of the most common environmental stresses that seriously affect the growth and development of plants. However, plants have the plasticity in their defence mechanisms enabling them to tolerate and, sometimes, even survive adverse environmental conditions. MicroRNAs (miRNAs) are small non-coding RNAs, approximately 18-24 nucleotides in length, and are being increasingly recognized as regulators of gene expression at the post-transcriptional level and have the ability to influence a broad range of biological processes. There is growing evidence in the literature that reprogramming of gene expression mediated through miRNAs is a major defence mechanism in plants enabling them to respond to stresses. To date, numerous studies have established the importance of miRNA-based regulation of gene expression under low temperature stress. Individual miRNAs can modulate the expression of multiple mRNA targets, and, therefore, the manipulation of a single miRNA has the potential to affect multiple biological processes. Numerous functional studies have attempted to identify the miRNA-target interactions and have elaborated the role of several miRNAs in cold-stress regulation. This review summarizes the current understanding of miRNA-mediated modulation of the expression of key genes as well as genetic and regulatory pathways, involved in low temperature stress responses in plants.

Evidence for ACD5 ceramide kinase activity involvement in Arabidopsis response to cold stress

Although sphingolipids emerged as important signals for plant response to low temperature, investigations have been limited so far to the function of long-chain base intermediates. The formation and function of ceramide phosphates (Cer-Ps) in chilled Arabidopsis were explored. Cer-Ps were analysed by thin layer chromatography (TLC) following in vivo metabolic radiolabelling. Ceramide kinase activity, gene expression and growth phenotype were determined in unstressed and cold-stressed wild type (WT) and Arabidopsis ceramide kinase mutant acd5. A rapid and transient formation of Cer-P occurs in cold-stressed WT Arabidopsis plantlets and cultured cells, which is strongly impaired in acd5 mutant. Although concomitant, Cer-P formation is independent of long-chain base phosphate (LCB-P) formation. No variation of ceramide kinase activity was measured in vitro in WT plantlets upon cold stress but the activity in acd5 mutant was further reduced by cold stress. At the seedling stage, acd5 response to cold was similar to that of WT. Nevertheless, acd5 seed germination was hypersensitive to cold and abscisic acid (ABA), and ABA-dependent gene expression was modified in acd5 seeds when germinated at low temperature. Our data involve for the first time Cer-P and ACD5 in low temperature response and further underline the complexity of sphingolipid signalling operating during cold stress.

Comparative Transcriptomics of Sijung and Jumli Marshi Rice during Early Chilling Stress Imply Multiple Protective Mechanisms

INTRODUCTION

Low temperature is one of the major environmental factors that adversely affect plant growth and yield. Many cereal crops from tropical regions, such as rice, are chilling sensitive and, therefore, are affected already at <10 °C. Interestingly, it has been demonstrated that chilling susceptibility varies greatly among rice varieties, which indicates differences in the underlying molecular responses. Understanding these differences is vital for continued development of rational breeding and transgenic strategies for more tolerant varieties. Thus, in this study, we conducted a comparative global gene expression profiling analysis of the chilling tolerant varieties Sijung and Jumli Marshi (spp. Japonica) during early chilling stress (<24 h, 10 °C).

METHODS AND RESULTS

Global gene expression experiments were conducted with Agilent Rice Gene Expression Microarray 4 x 44 K. The analysed results showed that there was a relatively low (percentage or number) overlap in differentially expressed genes in the two varieties and that substantially more genes were up-regulated in Jumli Marshi than in Sijung but the number of down-regulated genes were higher in Sijung. In broad GO annotation terms, the activated response pathways in Sijung and Jumli Marshi were coherent, as a majority of the genes belonged to the catalytic, transcription regulator or transporter activity categories. However, a more detailed analysis revealed essential differences. For example, in Sijung, activation of calcium and phosphorylation signaling pathways, as well as of lipid transporters and exocytosis-related proteins take place very early in the stress response. Such responses can be coupled to processes aimed at strengthening the cell wall and plasma membrane against disruption. On the contrary, in Jumli Marshi, sugar production, detoxification, ROS scavenging, protection of chloroplast translation, and plausibly the activation of the jasmonic acid pathway were the very first response activities. These can instead be coupled to detoxification processes.

CONCLUSIONS

Based on the results inferred from this study, we conclude that different, but overlapping, strategies are undertaken by the two varieties to cope with the chilling stress; in Sijung the initial molecular responses seem to be mainly targeted at strengthening the cell wall and plasma membrane, whereas in Jumli Marshi the protection of chloroplast translation and detoxification is prioritized.

Low Temperature-Induced 30 (LTI30) positively regulates drought stress resistance in Arabidopsis: effect on abscisic acid sensitivity and hydrogen peroxide accumulation

As a dehydrin belonging to group II late embryogenesis abundant protein (LEA) family, Arabidopsis Low Temperature-Induced 30 (LTI30)/XERO2 has been shown to be involved in plant freezing stress resistance. However, the other roles of AtLTI30 remain unknown. In this study, we found that the expression of AtLTI30 was largely induced by drought stress and abscisic acid (ABA) treatments. Thereafter, AtLTI30 knockout mutants and overexpressing plants were isolated to investigate the possible involvement of AtLTI30 in ABA and drought stress responses. AtLTI30 knockout mutants were less sensitive to ABA-mediated seed germination, while AtLTI30 overexpressing plants were more sensitive to ABA compared with wild type (WT). Consistently, the AtLTI30 knockout mutants displayed decreased drought stress resistance, while the AtLTI30 overexpressing plants showed improved drought stress resistance compared with WT, as evidenced by a higher survival rate and lower leaf water loss than WT after drought stress. Moreover, manipulation of AtLTI30 expression positively regulated the activities of catalases (CATs) and endogenous proline content, as a result, negatively regulated drought stress-triggered hydrogen peroxide (H2O2) accumulation. All these results indicate that AtLTI30 is a positive regulator of plant drought stress resistance, partially through the modulation of ABA sensitivity, H2O2 and proline accumulation.

The up-regulation of elongation factors in the barley leaf and the down-regulation of nucleosome assembly genes in the crown are both associated with the expression of frost tolerance

We report a series of microarray-based leaf and crown transcriptome comparisons involving three barley cultivars (cvs. Luxor, Igri and Atlas 68) which express differing degrees of frost tolerance. The transcripts were obtained following the exposure of seedlings to low (above and below zero) temperatures, aiming to identify those genes and signalling/metabolic pathways which are associated with frost tolerance. Both the leaves and the crowns responded to low temperature by the up-regulation of a suite of abscisic acid (ABA)-responsive genes, most of which have already been recognized as components of the plant low temperature response. The inter-cultivar comparison indicated that genes involved in maintaining the leaf's capacity to synthesize protein and to retain chloroplast activity were important for the expression of frost tolerance. In the crown, the repression of genes associated with nucleosome assembly and transposon regulation were the most relevant transcriptional changes associated with frost tolerance, highlighting the role of gene repression in the cold acclimation response.

OsRMC, a negative regulator of salt stress response in rice, is regulated by two AP2/ERF transcription factors

High salinity causes remarkable losses in rice productivity worldwide mainly because it inhibits growth and reduces grain yield. To cope with environmental changes, plants evolved several adaptive mechanisms, which involve the regulation of many stress-responsive genes. Among these, we have chosen OsRMC to study its transcriptional regulation in rice seedlings subjected to high salinity. Its transcription was highly induced by salt treatment and showed a stress-dose-dependent pattern. OsRMC encodes a receptor-like kinase described as a negative regulator of salt stress responses in rice. To investigate how OsRMC is regulated in response to high salinity, a salt-induced rice cDNA expression library was constructed and subsequently screened using the yeast one-hybrid system and the OsRMC promoter as bait. Thereby, two transcription factors (TFs), OsEREBP1 and OsEREBP2, belonging to the AP2/ERF family were identified. Both TFs were shown to bind to the same GCC-like DNA motif in OsRMC promoter and to negatively regulate its gene expression. The identified TFs were characterized regarding their gene expression under different abiotic stress conditions. This study revealed that OsEREBP1 transcript level is not significantly affected by salt, ABA or severe cold (5 °C) and is only slightly regulated by drought and moderate cold. On the other hand, the OsEREBP2 transcript level increased after cold, ABA, drought and high salinity treatments, indicating that OsEREBP2 may play a central role mediating the response to different abiotic stresses. Gene expression analysis in rice varieties with contrasting salt tolerance further suggests that OsEREBP2 is involved in salt stress response in rice.

An Arabidopsis R2R3-MYB transcription factor, AtMYB20, negatively regulates type 2C serine/threonine protein phosphatases to enhance salt tolerance

We have characterized the function of a plant R2R3-MYB transcription factor, Arabidopsis thaliana MYB20 (AtMYB20). Transgenic plants overexpressing AtMYB20 (AtMYB20-OX) enhanced salt stress tolerance while repression lines (AtMYB20-SRDX) were more vulnerable to NaCl than wild-type plants. Following NaCl treatment, the expressions of ABI1, ABI2 and AtPP2CA, which encode type 2C serine/threonine protein phosphatases (PP2Cs) that act as negative regulators in abscisic acid (ABA) signaling, were suppressed in AtMYB20-OX but induced in AtMYB20-SRDX. The electrophoretic mobility shift assay results revealed that AtMYB20 binds to the promoter regions containing the MYB recognition sequence (TAACTG) and an ACGT core element of ABI1 and AtPP2CA. These findings suggest that AtMYB20 down-regulates the expression of PP2Cs, the negative regulator of ABA signaling, and enhances salt tolerance.

Transcriptional profiling of bud dormancy induction and release in oak by next-generation sequencing

Background

In temperate regions, the time lag between vegetative bud burst and bud set determines the duration of the growing season of trees (i.e. the duration of wood biomass production). Dormancy, the period during which the plant is not growing, allows trees to avoid cold injury resulting from exposure to low temperatures. An understanding of the molecular machinery controlling the shift between these two phenological states is of key importance in the context of climatic change. The objective of this study was to identify genes upregulated during endo- and ecodormancy, the two main stages of bud dormancy. Sessile oak is a widely distributed European white oak species. A forcing test on young trees was first carried out to identify the period most likely to correspond to these two stages. Total RNA was then extracted from apical buds displaying endo- and ecodormancy. This RNA was used for the generation of cDNA libraries, and in-depth transcriptome characterization was performed with 454 FLX pyrosequencing technology.

Results

Pyrosequencing produced a total of 495,915 reads. The data were cleaned, duplicated reads removed, and sequences were mapped onto the oak UniGene data. Digital gene expression analysis was performed, with both R statistics and the R-Bioconductor packages (edgeR and DESeq), on 6,471 contigs with read numbers ≥ 5 within any contigs. The number of sequences displaying significant differences in expression level (read abundance) between endo- and ecodormancy conditions ranged from 75 to 161, depending on the algorithm used. 13 genes displaying significant differences between conditions were selected for further analysis, and 11 of these genes, including those for glutathione-S-transferase (GST) and dehydrin xero2 (XERO2) were validated by quantitative PCR.

Conclusions

The identification and functional annotation of differentially expressed genes involved in the “response to abscisic acid”, “response to cold stress” and “response to oxidative stress” categories constitutes a major step towards characterization of the molecular network underlying vegetative bud dormancy, an important life history trait of long-lived organisms.

RAP2.6L overexpression delays waterlogging induced premature senescence by increasing stomatal closure more than antioxidant enzyme activity

Waterlogging usually results from overuse or poor management of irrigation water and is a serious constraint due to its damaging effects. RAP2.6L (At5g13330) overexpression enhances plant resistance to jasmonic acid, salicylic acid, abscisic acid (ABA) and ethylene in Arabidopsis thaliana. However, it is not known whether RAP2.6L overexpression in vivo improves plant tolerance to waterlogging stress. In this study, the RAP2.6L transcript was induced by waterlogging or an ABA treatment, which was reduced after pretreatment with an ABA biosynthesis inhibitor tungstate. Water loss and membrane leakage were reduced in RAP2.6L overexpression plants under waterlogging stress. Time course analyses of ABA content and production of hydrogen peroxide (H(2)O(2)) showed that increased ABA precedes the increase of H(2)O(2). It is also followed by a marked increase in the antioxidant enzyme activities. Increased ABA promoted stomatal closure and made leaves exhibit a delayed waterlogging induced premature senescence. Furthermore, RAP2.6L overexpression caused significant increases in the transcripts of antioxidant enzyme genes APX1 (ascorbate peroxidase 1) and FSD1 (Fe-superoxide dismutase 1), the ABA biosynthesis gene ABA1 (ABA deficient 1) and signaling gene ABH1 (ABA-hypersensitive 1) and the waterlogging responsive gene ADH1 (alcohol dehydrogenase 1), while the transcript of ABI1 (ABA insensitive 1) was decreased. ABA inhibits seed germination and seedling growth and phenotype analysis showed that the integration of abi1-1 mutation into the RAP2.6L overexpression lines reduces ABA sensitivity. These suggest that RAP2.6L overexpression delays waterlogging induced premature senescence and might function through ABI1-mediated ABA signaling pathway.

Extracting plants core genes responding to abiotic stresses by penalized matrix decomposition

Sparse methods have a significant advantage to reduce the complexity of genes expression data and to make them more comprehensible and interpretable. In this paper, based on penalized matrix decomposition (PMD), a novel approach is proposed to extract plants core genes, i.e., the characteristic gene set, responding to abiotic stresses. Core genes can capture the changes of the samples. In other words, the features of samples can be caught by the core genes. The experimental results show that the proposed PMD-based method is efficient to extract the core genes closely related to the abiotic stresses.

Designer promoter: an artwork of cis engineering

Advances in systematic computational biology and rapid elucidation of synergistic interplay between cis and trans factors governing transcriptional control have facilitated functional annotation of gene networks. The generation of data through deconstructive, reconstructive and database assisted promoter studies, and its integration to principles of synthetic engineering has started an era of designer promoters. Exploration of natural promoter architecture and the concept of cis engineering have not only enabled fine tuning of single or multiple transgene expression in response to perturbations in the chemical, physiological and environmental stimuli but also provided researchers with a unique answer to various problems in crop improvement in the form of bidirectional promoters.

Supra-optimal expression of the cold-regulated OsMyb4 transcription factor in transgenic rice changes the complexity of transcriptional network with major effects on stress tolerance and panicle development

The R2R3-type OsMyb4 transcription factor of rice has been shown to play a role in the regulation of osmotic adjustment in heterologous overexpression studies. However, the exact composition and organization of its underlying transcriptional network has not been established to be a robust tool for stress tolerance enhancement by regulon engineering. OsMyb4 network was dissected based on commonalities between the global chilling stress transcriptome and the transcriptome configured by OsMyb4 overexpression. OsMyb4 controls a hierarchical network comprised of several regulatory sub-clusters associated with cellular defense and rescue, metabolism and development. It regulates target genes either directly or indirectly through intermediary MYB, ERF, bZIP, NAC, ARF and CCAAT-HAP transcription factors. Regulatory sub-clusters have different combinations of MYB-like, GCC-box-like, ERD1-box-like, ABRE-like, G-box-like, as1/ocs/TGA-like, AuxRE-like, gibberellic acid response element (GARE)-like and JAre-like cis-elements. Cold-dependent network activity enhanced cellular antioxidant capacity through radical scavenging mechanisms and increased activities of phenylpropanoid and isoprenoid metabolic processes involving various abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), ethylene and reactive oxygen species (ROS) responsive genes. OsMyb4 network is independent of drought response element binding protein/C-repeat binding factor (DREB/CBF) and its sub-regulons operate with possible co-regulators including nuclear factor-Y. Because of its upstream position in the network hierarchy, OsMyb4 functions quantitatively and pleiotrophically. Supra-optimal expression causes misexpression of alternative targets with costly trade-offs to panicle development.

AP2/EREBP transcription factors are part of gene regulatory networks and integrate metabolic, hormonal and environmental signals in stress acclimation and retrograde signalling

To optimize acclimation responses to environmental growth conditions, plants integrate and weigh a diversity of input signals. Signal integration within the signalling networks occurs at different sites including the level of transcription factor activation. Accumulating evidence assigns a major and diversified role in environmental signal integration to the family of APETALA 2/ethylene response element binding protein (AP2/EREBP) transcription factors. Presently, the Plant Transcription Factor Database 3.0 assigns 147 gene loci to this family in Arabidopsis thaliana, 200 in Populus trichocarpa and 163 in Oryza sativa subsp. japonica as compared to 13 to 14 in unicellular algae ( http://plntfdb.bio.uni-potsdam.de/v3.0/ ). AP2/EREBP transcription factors have been implicated in hormone, sugar and redox signalling in context of abiotic stresses such as cold and drought. This review exemplarily addresses present-day knowledge of selected AP2/EREBP with focus on a function in stress signal integration and retrograde signalling and defines AP2/EREBP-linked gene networks from transcriptional profiling-based graphical Gaussian models. The latter approach suggests highly interlinked functions of AP2/EREBPs in retrograde and stress signalling.

Transcriptional regulatory network triggered by oxidative signals configures the early response mechanisms of japonica rice to chilling stress

BACKGROUND

The transcriptional regulatory network involved in low temperature response leading to acclimation has been established in Arabidopsis. In japonica rice, which can only withstand transient exposure to milder cold stress (10 degrees C), an oxidative-mediated network has been proposed to play a key role in configuring early responses and short-term defenses. The components, hierarchical organization and physiological consequences of this network were further dissected by a systems-level approach.

RESULTS

Regulatory clusters responding directly to oxidative signals were prominent during the initial 6 to 12 hours at 10 degrees C. Early events mirrored a typical oxidative response based on striking similarities of the transcriptome to disease, elicitor and wounding induced processes. Targets of oxidative-mediated mechanisms are likely regulated by several classes of bZIP factors acting on as1/ocs/TGA-like element enriched clusters, ERF factors acting on GCC-box/JAre-like element enriched clusters and R2R3-MYB factors acting on MYB2-like element enriched clusters.Temporal induction of several H2O2-induced bZIP, ERF and MYB genes coincided with the transient H2O2 spikes within the initial 6 to 12 hours. Oxidative-independent responses involve DREB/CBF, RAP2 and RAV1 factors acting on DRE/CRT/rav1-like enriched clusters and bZIP factors acting on ABRE-like enriched clusters. Oxidative-mediated clusters were activated earlier than ABA-mediated clusters.

CONCLUSION

Genome-wide, physiological and whole-plant level analyses established a holistic view of chilling stress response mechanism of japonica rice. Early response regulatory network triggered by oxidative signals is critical for prolonged survival under sub-optimal temperature. Integration of stress and developmental responses leads to modulated growth and vigor maintenance contributing to a delay of plastic injuries.

ESKIMO1 is a key gene involved in water economy as well as cold acclimation and salt tolerance

BACKGROUND

Drought is a major social and economic problem resulting in huge yield reduction in the field. Today's challenge is to develop plants with reduced water requirements and stable yields in fluctuating environmental conditions. Arabidopsis thaliana is an excellent model for identifying potential targets for plant breeding. Drought tolerance in the field was successfully conferred to crops by transferring genes from this model species. While involved in a plant genomics programme, which aims to identify new genes responsible for plant response to abiotic stress, we identified ESKIMO1 as a key gene involved in plant water economy as well as cold acclimation and salt tolerance.

RESULTS

All esk1 mutants were more tolerant to freezing, after acclimation, than their wild type counterpart. esk1 mutants also showed increased tolerance to mild water deficit for all traits measured. The mutant's improved tolerance to reduced water supply may be explained by its lower transpiration rate and better water use efficiency (WUE), which was assessed by carbon isotope discrimination and gas exchange measurements. esk1 alleles were also shown to be more tolerant to salt stress. Transcriptomic analysis of one mutant line and its wild-type background was carried out. Under control watering conditions a number of genes were differentially expressed between the mutant and the wild type whereas under mild drought stress this list of genes was reduced. Among the genes that were differentially expressed between the wild type and mutant, two functional categories related to the response to stress or biotic and abiotic stimulus were over-represented. Under salt stress conditions, all gene functional categories were represented equally in both the mutant and wild type. Based on this transcriptome analysis we hypothesise that in control conditions the esk1 mutant behaves as if it was exposed to drought stress.

CONCLUSION

Overall our findings suggest that the ESKIMO1 gene plays a major role in plant response to water shortage and in whole plant water economy. Further experiments are being undertaken to elucidate the function of the ESKIMO1 protein and the way it modulates plant water uptake.