Project description:‘Pulsechip’, a boutique cDNA microarray, generated from a set of chickpea (Cicer arietinum L.) unigenes, grasspea (Lathyrus sativus L.) ESTs and lentil (Lens culinaris Med.) resistance gene analogs, was employed to generate an expression profile of chickpea accessions tolerant and susceptible to cold stress. Two groups of a tolerant and susceptible accession were challenged with cold stress. The experiments were performed in three biological replications. The experiments were conducted in reference design where respective tissues from unstressed plants served as control. The leaves and flowers/buds/early pods tissues were collected and used for hybridization to measure changes in RNA abundance of treatment vs. control. The tissues from five experimental replicate plants per biological replication were pooled together (leaf and flower tissues separate) before RNA extraction. This RNA was used to prepare cDNA targets for expression analysis using microarray. The microarray had six technical replicate spots per EST. The transcript level for each EST/cDNA was firstly calculated as the average intensity of the six technical replicates and then the average intensity of three biological replicates. Data analysis included LOWESS normalization (LOcally WEighted polynomial regreSSion) to adjust for differences in quantity of initial RNA, labeling and detection efficiencies. A dye swap in one biological replicate adjusted dye bias, if any. The Differentially Expressed (DE) ESTs were identified as those with a 95% confidence interval for mean fold change (FC) that extended beyond the two-fold cut-off and also passed the Students t test (P<0.05) and FDR correction. These cut-offs translate into induced ESTs having a log2 ratio > 1 and repressed ESTs a ratio of < -1. The analysis consisted of three fold comparison. Firstly, the ESTs that were differentially expressed between treatment and control plants of each accession were detected. Then the ESTs that were similarly expressed by tolerant and susceptible accessions were then eliminated by comparison. This included a two-way comparison, where tolerant and susceptible genotypes were compared within and between groups. Lastly, ESTs that were consensually differentially expressed between tolerant and susceptible accessions of the two batches were identified. The hypothesis was that if a putative gene was consistently expressed only in tolerant or susceptible genotype for a particular stress, it might be a candidate for tolerance/susceptibility for that stress. Globally, the level of 221 transcripts was affected in response to cold stress in all the genotypes and tissue types studied. The DE transcripts in response to cold stress fell into various functional categories, indicating a broad response. Sixteen out of the 221 DE transcripts were consistently expressed in cold tolerant/susceptible genotypes. All these transcripts were repressed and none was found to be consistently induced in response to cold-stress. Most of the putative genes were identified in leaves of tolerant genotypes, and included a beta-galactosidase (DY475141) transcript that was possibly indicative of disaccharide (e. g. sucrose) retention with the effect of protecting cell membranes during cold stress. Several protein synthesis/modification and energy/metabolism transcripts were also repressed (e.g. DY475282, DY396371 and DY475555), which was likely due to the impairment of photosynthesis and respiration at low temperature. Other consistently repressed transcripts in tolerant genotypes included putative signalling (DY396262, DY475384 and DY396307) and defence-related proteins (CV793589 and DY396343), which may be involved in the repression of cell death mechanisms that are absent in tolerant genotypes. In susceptible genotypes, a putative superoxide dismutase precursor protein (DY475397) and sorting nexin protein (DY475523) were the only known transcripts to be consistently repressed. Keywords: Chickpea, Cold stress, Tolerant, Susceptible, cDNA microarray

Project description:Background: Rice grain production is susceptible to a changing environment that imposes both biotic and abiotic stress conditions. Cold episodes are becoming more frequent in the last years and directly affect rice yield in areas with a temperate climate. Rice is particularly susceptible to cold stress during the reproductive phase, especially in anthers during post-meiotic stages which, in turn, affect pollen production. However, a number of rice cultivars with a certain degree of tolerance to cold have been described, which may represent a good breeding resource for improvement of susceptible commercial varieties. Plants experiencing cold stress activate a molecular response in order to reprogram many metabolic pathways to face these hostile conditions. Results: Here we performed RNA-seq analysis using cold-stressed post-meiotic anther samples from a cold-tolerant, Erythroceros Hokkaido (ERY), and a cold-susceptible commercial cultivar Sant´Andrea (S.AND). Both cultivars displayed an early common molecular response to cold, although the changes in expression levels are much more drastic in the tolerant one. Comparing our datasets, obtained after one-night cold stress, with other similar genome-wide studies showed very few common deregulated genes, leading to the conclusion that molecular responses in cold-stressed anthers strongly depend on conditions and the duration of the cold treatments. Cold-tolerant ERY exhibits specific molecular responses related to ethylene metabolism, which appears to be activated after cold stress. On the other hand, S.AND cold-treated plants showed a general downregulation of photosystem I and II genes, supporting a role of photosynthesis and chloroplasts in cold responses in anthers, which has remained elusive. Conclusions: Our study revealed that a number of ethylene-related transcription factors, as putative master regulators of cold responses, were upregulated in ERY providing promising candidates to confer tolerance to susceptible cultivars. Our results also suggest that the photosynthesis machinery might be a good target to improve cold tolerance in anthers. In summary, our study provides valuable candidates for further analysis and molecular breeding for cold-tolerant rice cultivars.

Project description:Background: MicroRNAs (miRNAs) are a class of single-stranded non-coding small RNAs (sRNAs) that are 20-24 nucleotides (nt) in length. Extensive studies have indicated that miRNAs play important roles in plant growth, development, and stress responses. With more copper (Cu) and copper-containing compounds used as bactericides and fungicides in viticulture, Cu stress has become one of the serious environmental problems that affect plant growth and development. In order to uncover the hidden response mechanisms of Cu stress, many Cu-responsive miRNAs have been detected in several plant species. However, there have been few reports about the grapevine miRNAs in response to Cu. Results: Here, two small RNA libraries were constructed from Cu-treated and water-treated (control) leaves of 'Summer Black' grapevine. Following high-throughput sequencing and filtering, 158 known vvi-miRNAs and 98 novel vvi-miRNAs were identified in the two libraries. Among these, 24 could only be detected in the treatment, and 63 were only detected in the control. Additionally, 100 known vvi-miRNAs were found to be clearly responsive to Cu, among which 96 were down-regulated and four were up-regulated; 47 novel vvi-miRNAs were found to be clearly responsive to Cu, among which 35 were down-regulated and 12 were up-regulated. Subsequently, expression patterns of a set of Cu-responsive vvi-miRNAs were validated by quantitative real-time PCR (qRT-PCR). There existed some consistency in expression levels of Cu-responsive vvi-miRNAs between high-throughput sequencing and qRT-PCR assays. In addition, 92 putative targets for 79 known vvi-miRNAs and 51 putative targets for 22 novel vvi-miRNAs were predicted, and most of the targets are involved in multiple biological processes including transcriptional regulation and response to biotic and abiotic stresses. Conclusions: In this study, 147 Cu-responsive vvi-miRNAs were identified using high-throughput sequencing, and their target genes were predicted, which will be helpful to understanding the molecular mechanisms of miRNAs in response to Cu stress. Furthermore, this work can also provide a foundation for further study of the networks of miRNAs involved in grapevine plant growth and breeding some Cu-tolerant grapevine cultivars. Mixed 'Summer Black' grapevine young leaves (2 weeks old), large leaves (5 weeks old), and old leaves (9 week old) in randomly-selected plants from both the Cu-treated and control groups were collected for high-throughput sequencing. Subsequently, we carried out the analysis of Solexa sequencing data, and performed the research of regulatory modes of grapevine miRNAs on their target genes during Cu stress.

Project description:Background: MicroRNAs (miRNAs) are a class of single-stranded non-coding small RNAs (sRNAs) that are 20-24 nucleotides (nt) in length. Extensive studies have indicated that miRNAs play important roles in plant growth, development, and stress responses. With more copper (Cu) and copper-containing compounds used as bactericides and fungicides in viticulture, Cu stress has become one of the serious environmental problems that affect plant growth and development. In order to uncover the hidden response mechanisms of Cu stress, many Cu-responsive miRNAs have been detected in several plant species. However, there have been few reports about the grapevine miRNAs in response to Cu. Results: Here, two small RNA libraries were constructed from Cu-treated and water-treated (control) leaves of 'Summer Black' grapevine. Following high-throughput sequencing and filtering, 158 known vvi-miRNAs and 98 novel vvi-miRNAs were identified in the two libraries. Among these, 24 could only be detected in the treatment, and 63 were only detected in the control. Additionally, 100 known vvi-miRNAs were found to be clearly responsive to Cu, among which 96 were down-regulated and four were up-regulated; 47 novel vvi-miRNAs were found to be clearly responsive to Cu, among which 35 were down-regulated and 12 were up-regulated. Subsequently, expression patterns of a set of Cu-responsive vvi-miRNAs were validated by quantitative real-time PCR (qRT-PCR). There existed some consistency in expression levels of Cu-responsive vvi-miRNAs between high-throughput sequencing and qRT-PCR assays. In addition, 92 putative targets for 79 known vvi-miRNAs and 51 putative targets for 22 novel vvi-miRNAs were predicted, and most of the targets are involved in multiple biological processes including transcriptional regulation and response to biotic and abiotic stresses. Conclusions: In this study, 147 Cu-responsive vvi-miRNAs were identified using high-throughput sequencing, and their target genes were predicted, which will be helpful to understanding the molecular mechanisms of miRNAs in response to Cu stress. Furthermore, this work can also provide a foundation for further study of the networks of miRNAs involved in grapevine plant growth and breeding some Cu-tolerant grapevine cultivars.

			Action	DRS
	SRR28065200_1.fastq.gz	Fastqsanger.gz
	SRR28065200_2.fastq.gz	Fastqsanger.gz
	SRR28065201_1.fastq.gz	Fastqsanger.gz
	SRR28065201_2.fastq.gz	Fastqsanger.gz
	SRR28065202_1.fastq.gz	Fastqsanger.gz

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