De novo genome assembly of faba bean (Vicia faba L.) leaf transcriptome provide novel insights into the drought stress tolerance mechanisms
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ABSTRACT: Drought is a major limiting constraint to faba bean production worldwide, including Tunisia. However, molecular mechanisms underlying faba bean responses to drought stress are not well understood. In this context, transcriptome analysis by RNA-seq was performed to investigate drought-related genes and construct a network of faba bean drought stress response and tolerance. De novo assembly of the transcriptome generated 26,728 differentially expressed genes (DEGs). Of these, 13,920 were up-regulated and 12,808 down-regulated in faba bean drought-stressed leaves. Moreover, a total of 10,800 simple sequence repeats (SSRs) and 2130 transcription factors involved in major metabolic pathways including abscisic acid (ABA)-dependent and -independent signaling pathway were identified. GO, KOG and KEGG enrichment analyses revealed that these DEGs were involved in several important processes including photosynthesis, flavonoid biosynthesis, response to stimulus and abiotic stress, reactive oxygen species (ROS) scavengers, signal transduction, biosynthesis of secondary metabolites and transporters, suggesting the involvement of these important pathways in faba bean response to water deficit. Various stress proteins such as late embryogenesis abundant proteins (LEA), dehydrins (DHNs) and heat shock proteins (HSPs) have been identified and their expression was robustly upregulated in drought-stressed leaves, indicating their key contribution to drought response and adaptation by conferring protection and providing stability to faba bean plant cellular processes under water deficit. The reliability of the RNA-seq results was confirmed by the analysis of 10 randomly selected genes using qRT-PCR. Taken together, these findings help advancing our knowledge and can guide breeding programs aimed at improving the tolerance of faba bean to drought stress.
Project description:Drought is one of the major factor that limits crop production and reduces yield. To understand the early response of plants under nearly natural conditions, pepper plants were grown in a greenhouse and drought stressed by withholding water for one week. Plants adapted to the decreasing water content of the substrate by adjustment of their osmotic potential in roots by accumulation of raffinose, glucose, galactinol and proline. In contrast in leaves levels of fructose, sucrose and also galactinol increased. Due to the water deficit cadaverine, putrescine, spermidine and spermine accumulated in leaves whereas the concentration of polyamines was reduced in roots. These polyamines are suggested to rather act as stress protectants than for osmotic adjustment. To understand the molecular basis of the response to this early drought stress better, four suppression subtractive hybridisation libraries from leaves and roots were constructed. Microarray technique was used to identify differentially expressed genes. A total of 109 unique ESTs were detected. The diversity of the putative functions of all identified genes confirms the complexity of the plant response to drought stress. Keywords: Transcription profiling Two-condition experiment in roots and leaves, control leaves (CL) vs. drought-stressed leaves (DL) and control roots (CR) vs. drought-stressed roots (DR). Biological replicates: 4 control (1-4), drought-stressed (1-4), independently grown and harvested. One swap replicate per array.
Project description:Drought is one of the major factor that limits crop production and reduces yield. To understand the early response of plants under nearly natural conditions, pepper plants were grown in a greenhouse and drought stressed by withholding water for one week. Plants adapted to the decreasing water content of the substrate by adjustment of their osmotic potential in roots by accumulation of raffinose, glucose, galactinol and proline. In contrast in leaves levels of fructose, sucrose and also galactinol increased. Due to the water deficit cadaverine, putrescine, spermidine and spermine accumulated in leaves whereas the concentration of polyamines was reduced in roots. These polyamines are suggested to rather act as stress protectants than for osmotic adjustment. To understand the molecular basis of the response to this early drought stress better, four suppression subtractive hybridisation libraries from leaves and roots were constructed. Microarray technique was used to identify differentially expressed genes. A total of 109 unique ESTs were detected. The diversity of the putative functions of all identified genes confirms the complexity of the plant response to drought stress. Keywords: Transcription profiling
Project description:affy_popsec_nancy_leaves_poplar - affy_popsec_nancy_leaves2007_poplar - This project aims to identify genes of interest for water deficit acclimation and/or adaptation in a tree species: poplar. We look for genes and gene expression networks related to drought stress. We intend to analyse the transcriptome in mature leaves, in two genotypes, Carpaccio and Soligo, at various stages and intensities of stress. During water deficit, leaves underwent many processes aiming to maintain cells integrity such as water status adjustment through osmoregulation or cell detoxication. These analyses intend to identify genes of interest involved in homeostasis maintenance. The comparison between medium and severe stress intensities and between early and long term stresses will power the selection of genes of interest. The co-analysis of two genotypes of contrasted tolerance to water deficit should help to discriminate genes presenting a potential adaptative character from genes responding passively to the constraint-In a first experiment, two poplar clones, Soligo (S) and Carpacio (C) were submitted to 4 treatments: control, mild water deficit, moderate water deficit (12-day long for both) and early-drought stress (about 36-h long). Growth and physiology was characterised on a batch of plants and samples collected on another batch of plants. In a second experiment, two poplar clones, Soligo (S) and Carpacio (C) were submitted to 2 treatments: control and moderate water deficit. Mature leaves were collected and total RNAs were extracted from each tree individually. Two pools of 3 (or 2) individuals were made using equimolar ratio. A pool is considered as one biological replicate and corresponds to one Affimetrix slide. Keywords: treated vs untreated comparison
Project description:affy_popsec_nancy_leaves_poplar - affy_popsec_nancy_leaves2008_poplar - This project aims to identify genes of interest for water deficit acclimation and/or adaptation in a tree species: poplar. We look for genes and gene expression networks related to drought stress. We intend to analyse the transcriptome in mature leaves, in two genotypes, Carpaccio and Soligo, at various stages and intensities of stress. During water deficit, leaves underwent many processes aiming to maintain cells integrity such as water status adjustment through osmoregulation or cell detoxication. These analyses intend to identify genes of interest involved in homeostasis maintenance. The comparison between medium and severe stress intensities and between early and long term stresses will power the selection of genes of interest. The co-analysis of two genotypes of contrasted tolerance to water deficit should help to discriminate genes presenting a potential adaptative character from genes responding passively to the constraint-In a first experiment, two poplar clones, Soligo (S) and Carpacio (C) were submitted to 4 treatments: control, mild water deficit, moderate water deficit (12-day long for both) and early-drought stress (about 36-h long). Growth and physiology was characterised on a batch of plants and samples collected on another batch of plants. In a second experiment, two poplar clones, Soligo (S) and Carpacio (C) were submitted to 2 treatments: control and moderate water deficit. Mature leaves were collected and total RNAs were extracted from each tree individually. Two pools of 3 (or 2) individuals were made using equimolar ratio. A pool is considered as one biological replicate and corresponds to one Affymetrix slide. Keywords: treated vs untreated comparison
Project description:Structural and functional approaches were used to study cotton (Gossypium) genes implicated in water-deficit stress. A genetic map representing the hypothetical ancestral diploid genome (Consensus Map) was used to map 1,907 of 15,784 tentative consensus sequences (TCs). These TCs represent 25,119 cotton ESTs derived from various tissues under irrigated and water-limited condition. The correspondence of mapped TCs and 42 stress-related quantitative trait loci (QTLs) revealed that 391 of the initial 1907 TCs co-localized within a QTL interval. About 31% of these TCs were annotated as genes involved in plant responses to abiotic stress. By comparison, only 18% of the total annotated TCs mapped on the Consensus map were classified as abiotic stress genes. The enrichment of stress-related TCs that map to stress-related QTLs could not be explained by chance (P = 1.5 x 10-7). Gene expression profiling experiments were carried out using a microarray composed of 12,006 oligonucleotides. Transcriptional responses to imposed water-deficit stress in root and leaf tissue of 8-week old cotton plants revealed 1401 transcripts identified as drought responsive. A total of 158 (84 drought-induced and 74 drought-repressed) genes were mapped, of which 22 (8 induced and 14 repressed) genes co-localized with a QTL. A total of 539 unique genes were identified in the drought-stressed libraries. However, only 91 of these genes are contained on the array. Of these genes, 12 showed significant changes in transcript abundance between stressed and irrigated leaf and root. Forty-five candidate genes implicated in drought-stress response at some level of characterization were identified. Keywords: stress response
Project description:affy_popsec_nancy_pophydro_roots_poplar - This project aims to identify genes of interest for control of root growth in response to water deficit in a tree species: poplar. We look for genes and gene expression networks related to drought stress. We intend to analyse the transcriptome in root apices of cuttings grown in hydroponics and osmotically stressed with PEG. Root apex is the location of root elongation and these analyses intend to identify genes involved in the control of cell expansion and thus of root elongation. Indeed, root growth maintenance in response to water shortage contributes to plant tolerance to water deficit.-Poplar cuttings (cv Soligo) were grown in hydroponics. A moderate water deficit was applied by adding PEG to the nutrient solution (200g/l). After 3 days, the apex (1 cm-long) of the roots of each cutting were collected. For control and stressed treatments, RNAs were extracted from two pools of 5 to 9 roots (issued from 2 to 5 cuttings). A pool is considered as one biological replicate and corresponds to one Affymetrix slide. Keywords: treated vs untreated comparison
Project description:Periods of soil water deficit could occur at any time during the crop season, but maize is particularly sensitive to water stress around flowering time. At this time the stress usually causes remarkable yield loss. Heading time, which is just before tassel flowering, is one of the most important stages that maize productivity would be affected severely if plants encounter water stress. The whole-genomic gene expression changes of maize plants in response to water deficit stress at this stage have not been studied. The present work utilized an Arizona Maize Oligonucleotide Array Version 1.9ï¼which was consisted of A and B slides carrying with a total of 57,452 maize 70-mer oligonucleotides, was used to monitor gene expression profile changes in maize leaves subjected to 1 day and 7 days water-deficit stress respectively at the heading stage. Keywords: stress response Maize (Zea mays L.) inbred line DH4866 was used in this study. Plants grew in flowerpots containing field soil under natural conditions. When the tassel spread out of the uppermost leaf, some plants were treated with drought stress for 7 days, and others were left under normal-watered conditions as control. In the period of the stress, the middle part of the top fully expanded leaves of the plants under water stress treatment and the control were taken to measure the leaf osmotic potential at different times by the Fiske® Micro-Osmometer (FISKE® ASSOCIATES, USA). And the stressed plants were watered every day to maintain a similar water-deficiency state by adjusting water supply, according to the osmotic potential of the fully expended leaf of the plants measured at 8:00 am each day. During the stress, the leaf osmotic potential of the stressed plants was hold to -0.4 to -0.5 Mpa, while the osmotic potential was -0.2 to -0.25 Mpa in the leaves of the control plants. And there were visible signs of water deficiency such as leaf rolling during the daytime, though at night the rolled leaves spread out. Maize plants were stress-treated at the beginning of heading stage. After 7 days of water deficiency by withholding water, the plants began to enter the flowering stage. The maize flag leaves were harvested after 24h (1d) and 168h ï¼7dï¼ of stress treatment, frozen in liquid nitrogen immediately and stored at -80â for further analysis. Unstressed plants as controls were harvested at the same time as the stressed plants. One sample consisted of the leaves from three independent plants under the same condition. Total RNA was isolated as McCarty (1986) described from the frozen samples. For each sample, 100ïg of total RNA was transcribed into cDNA and fluorescently labeled with Cy3 and Cy5 dyes using the SuperScript indirect cDNA labeling system (INVITROGEN, USA) according to the manufacturerâs instructions. The Cy3 and Cy5 labels were swapped between sample and control cDNA to minimize any possible impact of inequalities in DNA incorporation and photobleaching of the fluorescent dyes. Hybridizations were performed according to the protocols at the website of the Maize Oligonucleotide Array Project. Two technical replicates (dye-swap experiments) for each biological sample from two independent treatments were performed.
Project description:affy_popsec_nancy_pophydro_roots_poplar - This project aims to identify genes of interest for control of root growth in response to water deficit in a tree species: poplar. We look for genes and gene expression networks related to drought stress. We intend to analyse the transcriptome in root apices of cuttings grown in hydroponics and osmotically stressed with PEG. Root apex is the location of root elongation and these analyses intend to identify genes involved in the control of cell expansion and thus of root elongation. Indeed, root growth maintenance in response to water shortage contributes to plant tolerance to water deficit.-Poplar cuttings (cv Soligo) were grown in hydroponics. A moderate water deficit was applied by adding PEG to the nutrient solution (200g/l). After 3 days, the apex (1 cm-long) of the roots of each cutting were collected. For control and stressed treatments, RNAs were extracted from two pools of 5 to 9 roots (issued from 2 to 5 cuttings). A pool is considered as one biological replicate and corresponds to one Affymetrix slide. Keywords: treated vs untreated comparison 4 arrays - poplar
Project description:Cotton productivity is affected by water deficit and little is known about the molecular basis of drought tolerance in cotton. In this study, microarray analysis was carried out to identify drought responsive genes in functional leaves of the field-grown drought stressed cotton (Gossypium hirsutum L.) Acala 1517-99. The water stress was imposed after withholding irrigation for 9 days in the early squaring stage, which resulted in 10-15% reduction in plant growth compared to the well watered plants. A total of 110 drought responsive genes (0.5% of the total genes represented in the microarray) were identified, 79% (88 genes) of which were down-regulated and 21% (22 genes) were up-regulated by water stress. The responsiveness of 19 selected drought responsive genes was validated by real time PCR. The drought inducible genes were grouped into six functional categories only including stress related (10 genes, 9 of which are heat shock proteins), metabolism (3) and one each for transcription factor, proline biosynthesis and cellular transport. The down-regulated genes were classified into 14 functional categories including metabolism (20 genes), cellular transport (12), stress related (12), and regulation of gene expression (9) and transcription factor (4), signal transduction (7) and 2 genes each for biosynthesis of secondary compounds, cell wall, fatty acids/lipids and chlorophyll, and protein degradation. Most of the genes have been reported in other plants as drought tolerant/responsive and only 21 drought responsive genes (19%) were functionally unknown. The genes identified provides the first glimpse into the molecular basis of drought response in cotton.
Project description:Drought is one of the most crucial environmental stresses limiting faba bean growth and productivity in the Mediterranean region. In order to explore how the faba bean plant responds to drought stress, a physiological and proteomic analysis was performed in leaf tissue. All physiological parameters were affected by drought. The physiological mechanism underlying the response of faba bean leaves to drought was therefore attributed to the alleviation of oxidative stress via the accumulation of organic solutes such as proline and to the synergistic action of the antioxidant enzyme system (CAT, SOD, APX and GPOX). Proteomic analysis identified 2000 proteins from faba bean leaves, of which were 81 differentially expressed. Of those, 45 were upregulated and 36 were downregulated under drought treatment. GO and KEGG enrichments indicated differentially abundant proteins (DAPs) associated with photosynthesis, antioxidants/detoxifying enzymes, molecular chaperones, biosynthesis of amino acids and secondary metabolites, signal transduction, energy and carbohydrate metabolism and metabolic enzymes. The current results provide evidence for a complex synergetic pathway, in which ROS detoxification mechanisms and photoprotection constituted the major aspect of drought tolerance in faba bean leaves. These results offer a foundational basis regarding the molecular mechanism involved in drought resistance within the faba bean species