Project description:Plants remember what they have experienced and are thereby able to confront repeated stresses more promptly and strongly. A subset of genes showed increased transcript levels under drought stress conditions, followed by a return to basal levels during recovery (watered) states, and then displayed elevated levels again under subsequent drought conditions. To screen for a set of drought stress memory genes in soybean (Glycine max L. cv. Daepoong), we designed a 180K DNA chip comprising 60-bp probes synthesized in situ to examine 55,588 loci. Through microarray analysis using the DNA chip, we identified 2,165 and 2,385 genes with more than 4-fold increases or decreases in transcript levels, respectively, under initial (first) drought stress conditions, when compared with the non-treated control. The transcript levels of the genes returned to basal levels during recovery (watered) states, then 677 and 987 genes displayed more than 16-fold elevated or reduced levels, respectively, under subsequent (second) drought conditions, when compared to the non-treated control. Gene Ontology analysis classified the drought stress memory genes into several functional categories, including those involved in trehalose biosynthesis and drought tolerance responses. We selected a number of drought stress memory genes encoding various transcription factors, protein phosphatase 2Cs, and late embryogenesis abundant proteins, and confirmed the microarray data by quantitative reverse-transcription real-time PCR. Upon repeated watering and subsequent (third) drought treatment, the elevated levels of the drought stress memory gene transcripts were propagated into newly developed second leaves, although at reduced levels when compared to the second drought treatment on the first leaves.
Project description:RNA splicing is a molecular mechanism to increase protein diversities acquired through the evolution while the underlieing driving forces for the phenomenon are unknown especially in terms of gene expression. Rice alternatively spliced transcript detecting microarray (ASDM) was designed and applied to differentiate the transcriptome of 4 representative organs of Oryza sativa L. cv. Ilmi including leaves, roots, panicles at 1 cm stage and young seeds at 20 days after pollination. The comparison of the data between the microarray and RNA-seq shows a ‘bell shape distribution’ and a strong co-lineation for highly expressed genes. The transcripts are classified according to the degree of organ enrichment using coefficient value (CV, the ratio of standard deviation to the mean values); highly variable (CVI), variable (CVII), and constitutive (CVIII) groups. The genes of highly variable group show the characteristics of the organs. The index of the portion of loci with alternatively spliced transcripts in a group (IAS) is designated for these CV groups and showed the higher value in the constitutive group. In addition, within a locus, a transcript with longer cds tends to be higher expressed and the spliced_intron is the most commonly found type of alternative splicing for the extended cds. Thus, constitutively expressed genes might be under evolutionary pressure toward alternative splicing that might have a longer cds. These data show that less resource consuming and better designed microarray might be a niche technology to test the transcriptome analysis including alternatively spliced transcripts in plants.
Project description:Systematic mutagenesis has revealed that synonymous, non-synonymous and intronic mutations frequently alter the inclusion levels of alternatively spliced exons, suggesting that altered splicing might be a common mechanism by which mutations cause disease. However, most exons expressed in any cell are highly-included in mature mRNAs. Here, by performing deep mutagenesis of highly-included exons and by analysing the association between sequence variation and exon inclusion across the genome, we report that mutations only very rarely alter the inclusion of highly-included exons. This is true for both exonic and intronic mutations as well as for perturbations in trans. Therefore, mutations that affect splicing are not evenly distributed across the genome but are focussed in and around alternatively spliced exons with intermediate inclusion levels. These results provide a resource for prioritising synonymous and other variants as disease-causing mutations.
Project description:Transcript profiling of control vs Mungbean yellow mosaic India virus infected Glycine max variety JS335. RNA samples were collected at 2 dpi to study change in transcript profile at early infection.