Project description:Transcriptome sequencing (RNA-seq) was used to profile genome-wide transcript abundance in the primary root growth zone (PRGZ) of maize seedlings grown in different water deficit treatments: well-watered (-0.02 MPa), mild water deficit stress (-0.3 MPa), or severe water deficit stress (-1.6 MPa). For each water deficit treatment, the PRGZ transcriptome was profiled at 26 hours after initiation of the water deficit treatment. By comparing the abundance of each transcript under mild or severe water deficit stress relative to its abundance under well-watered conditions, we identified transcripts that are differentially regulated in the PRGZ in response to the two levels of water deficit stress.
Project description:Background: MicroRNAs are endogenous small noncoding RNAs that play critical roles in plant abiotic stress responses. The interaction between miRNA-mRNA targets and their regulatory pathways in response to water deficit stress has been investigated in many plant species. However, the miRNA transcriptome of durum wheat (Triticum turgidum L. ssp. durum) is poorly characterised, with little known about miRNA functions related to water deficit stress. Yield loss in durum wheat can be exacerbated due to minimal rainfall in the early reproductive stages of development during Spring in Australia. This study describes genotypic differences in the miRNAome between water deficit tolerant/sensitive durum, using flag leaf and developing head tissue, and more specifically identifies miRNAs associated with water deficit stress. Results: Small RNA libraries (96 in total) were constructed from flag leaf and developing head tissues of four durum genotypes (Tamaroi, Yawa, EGA Bellaroi, Tjilkuri), with or without water deficit stress. Illumina sequencing and subsequent analysis detected 110 conserved miRNAs and 159 novel candidate miRNA hairpins. Statistical analysis of the abundance of sequencing reads revealed 66 conserved miRNAs and five novel miRNA hairpins showing differential expression under water deficit stress. During stress, several conserved and novel miRNAs showed unambiguous inverted regulatory profiles between the durum genotypes studied. Several miRNAs were also identified to have different abundance in the flag leaf compared to the developing head regardless of treatment. Predicted mRNA targets from four novel durum miRNAs were characterised using Gene Ontology (GO) which revealed functions common to stress responses and plant development. Conclusion: For the first time, we present a comprehensive study of the miRNA transcriptome of flag leaf and developing head tissues in different durum genotypes under water deficit stress. The identification of differentially expressed miRNAs provides molecular evidence that miRNAs are potential determinants of water stress tolerance in durum wheat. GO analysis of predicted targets contributes to the understanding of genotype-specific physiological responses leading to stress tolerance capacity. Further functional analysis of specific stress responsive miRNAs identified, and their interaction with mRNA targets is ongoing and will assist in developing future durum wheat varieties with enhanced water deficit stress tolerance.
Project description:Switchgrass (Panicum virgatum L.) has been subject to breeding to improve its yield and composition for bioenergy, but improving its tolerance to environmental variability is just beginning. Different ploidy populations act as somewhat distinct gene pools which can only be bridged through whole genome reduction or duplication events. In order to document potential wide-ranging effects of whole genome duplication, we examined the effects of water stress on growth, physiology, and gene expression in individual tetraploid clones of the switchgrass cultivar ‘Liberty’ as well as neo-octoploid lines derived from it. The neo-octoploids behaved similarly to Liberty under water-stress and recovery conditions. Growth rates, photosynthesis, gas exchange, node numbers, and height were reduced in plants under water stress while proline levels were increased. A total of 6134 differentially expressed genes (8% of the annotated genes with detectable expression in crown tissue) were detected under water deficit stress, while 3310 differentially expressed genes were detected in crown tissue after 1 week of recovery from water deficit stress relative to well-watered treatments. Only a small number of genes were identified as being differentially expressed between 4x Liberty and its 8x derivatives.
Project description:By sequencing 36 cDNA libraries with Illumina technology, we identified genes differentially expressed in soybean plants in response to water deficit and genes that were either up- or down-regulated in different periods of the day. Of 54,175 predicted soybean genes (Glyma v1.1), 35.52% exhibited expression oscillations in a 24 h period. This number increased to 39.23% when plants were submitted to water deficit. Major differences in gene expression were observed in the control plants from late day (ZT16) until predawn (ZT20) periods, indicating that gene expression oscillates during the course of 24 h in normal development. Under water deficit, dissimilarity increased in all time-periods, indicating that the applied stress influenced gene expression. Results suggest that time of day, as well as light and temperature oscillations that occur considerably affect the regulation of water deficit stress response in soybean plants. Gene expression analysis of soybean leaves under water deficit in 6 periods of day by sequencing 36 libraries, in triplicate, in Illumina platform.
Project description:Soybean plants were subjected to water deficit, heat stress, and combination of water deficit and heat stress. Flower parts, sepal, anther, ovary and stigma were collected from 8-10 different plants at R1 stage growing under three above mentioned stress conditions, and under control conditions 10 days after initiation of the stresses. Differential gene expression compared to control was studied using RNAseq method.
Project description:Soybean plants were subjected to a multifactorial stress combination of up to five different stresses (water deficit, salinity, low phosphate, acidity, and cadmium), in an increasing level of complexity. All stresses were applied at the beginning of the experiment except for water deficit stress that was imposed after 21 days. Leaves and flowers were collected from 5-7 different plants under the mentioned stress conditions and after 10 days of starting water deficit conditions. Differential gene expression compared to control was studied using RNAseq method for all the possible stress combinations.
Project description:By sequencing 36 cDNA libraries with Illumina technology, we identified genes differentially expressed in soybean plants in response to water deficit and genes that were either up- or down-regulated in different periods of the day. Of 54,175 predicted soybean genes (Glyma v1.1), 35.52% exhibited expression oscillations in a 24 h period. This number increased to 39.23% when plants were submitted to water deficit. Major differences in gene expression were observed in the control plants from late day (ZT16) until predawn (ZT20) periods, indicating that gene expression oscillates during the course of 24 h in normal development. Under water deficit, dissimilarity increased in all time-periods, indicating that the applied stress influenced gene expression. Results suggest that time of day, as well as light and temperature oscillations that occur considerably affect the regulation of water deficit stress response in soybean plants.
Project description:Genome-wide transcriptome analysis was performed to understand the expression pattern of transcriptomes in tolerant and susceptible subtropical maize genotypes under water deficit stress condition.<br><br>
Project description:In light of the changes in precipitation and soil water availability expected with climate change, understanding the mechanisms underlying plant responses to water deficit is essential. Toward that end we have conducted an integrative analysis of responses to drought stress in the perennial C4 grass and biofuel crop, Panicum virgatum (switchgrass). Responses to soil drying and re-watering were measured at transcriptional, physiological, and metabolomic levels. To assess the interaction of soil moisture with diel light:dark cycles, we profiled gene expression in drought and control treatments under pre-dawn and mid-day conditions. Soil drying resulted in reduced leaf water potential, gas exchange, and chlorophyll fluorescence along with differential expression of a large fraction of the transcriptome (37%). Many transcripts responded differently depending on time of day (e.g. up-regulation pre-dawn and down-regulation mid-day). Genes associated with C4 photosynthesis were down-regulated during drought, while C4 metabolic intermediates accumulated. Rapid changes in gene expression were observed during recovery from drought, along with increased water use efficiency and chlorophyll fluorescence. Our findings demonstrate that drought responsive gene expression depends strongly on time of day and that gene expression is extensively modified during the first few hours of drought recovery. Analysis of covariation in gene expression, metabolite abundance, and physiology among plants revealed non-linear relationships that suggest critical thresholds in drought stress responses. Future studies may benefit from evaluating these thresholds among diverse accessions of switchgrass and other C4 grasses. mRNA profiles of leaf tissue from clonal replicates at various time points during drydown and recovery were generated by deep sequencing 3' mRNA tags using SOLiD.
Project description:The transcriptome profiling of three samples in A. mongolicum Keng were studied using next-generation RNA sequencing under different drought stress conditions. This study aimed to identify genes of A. mongolicum Keng metabolism pathways that might be involved in this plant’s response to water deficit. 14.33 Gb high quality reads were assembled into 92,752 unigenes (unique transcripts), with a mean length of 1,303 bp. 76.26% had homologous genes in function databases.