Project description:The diurnal transcriptome of field-grown Glycine max was investigated in relation to diurnal physiological processes in the field and compared to diurnal transcription data from growth chamber studies
Project description:Xanthomonas axonopodis pv. manihotis (Xam) is a gram negative bacterium causing Cassava Bacterial Blight (CBB), an important limitation for cassava production. The genetic bases underlying cassava resistance and susceptibility to different Xam strains are currently unknown. To identify genes and pathways important for the interaction, we used RNA-seq data to study transcriptomic changes in cassava plants inoculated with the non-pathogenic Xam strain, (ORST4) and a pathogenic strain, ORST4 transformed with the TAL effector TALE1Xam (ORST4+TALE1Xam). This analysis revealed that transcriptomic responses to both strains were very similar and were dominated by the induction of genes related to photosynthesis and phenylpropanoid biosynthesis and the down-regulation of genes related to jasmonic acid signaling, features possibly related to defense responses. Among the genes induced exclusively in cassava plants inoculated with ORST4 + TALE1Xam we found one gene containing a predicted binding site for TALE1Xam in its promoter region. This gene encodes for a Heat Shock Transcription Factor B3 (HsfB3) and likely acts a transcriptional repressor. HsfB3 may constitute a new type of susceptibility gene activated by a TAL effector that manages to be sufficient for symptom development without suppressing defense responses in the plant. mRNA of Cassava stems inoculated with a non-pathogenic (ORST4) and pathogenic (+TALE1Xam) strain of Xanthomonas axonopodis pv. Manihotis, tissues collected at 0, 5 and7 days post-inoculation, 2 technical replicates used
Project description:Cassava is the most important root crop in the tropics but rapid post-harvest physiological root deterioration (PPD) is a major constraint to commercial cassava production. We used label-free quantitative proteomics to generate an extensive cassava root and PPD proteome. Over 2400 unique proteins were identified in the cassava root and nearly 300 proteins showed significant abundance regulation during PPD. A candidate gene for reducing PPD was identified from the regulated proteins with enzymatic assays and afterwards verified with a transgene approach. This demonstrates the relevance of proteomics approach for crop improvements.
Project description:Mechanisms related to the development of cassava storage roots and starch accumulation remain largely unknown. To evaluate genome-wide expression patterns during cassava tuberization, a 60-mer oligonucleotide microarray representing 20,840 cassava genes was designed to identify differentially expressed transcripts in fibrous root, developing storage root and mature storage root. Using a random variance model and the traditional two-fold change method for statistical analysis, 912 and 3386 differentially expressed genes were identified related to the three different phases. Among 25 significant pathways identified, glycolysis/gluconeogenesis was the most important pathway signature due to its effects on other pathways. Rate-limiting enzymes were identified from each individual pathway, such as pectinesterase, enolase, L-lactate dehydrogenase and aldehyde dehydrogenase in glycolysis/gluconeogenesis, and ADP-glucose pyrophosphorylase, starch branching enzyme and glucan phosphorylase in sucrose and starch metabolism. This study revealed that dynamic changes in at least 16% of the transcriptome, including hundreds of transcription factors, oxidoreductases/transferases/hydrolases, hormone-related genes, and effectors of homeostasis, all of which highlight the complexity of this biological process. The reliability of differentially expressed genes in microarray analysis was further verified by quantitative real-time RT-PCR. The genome-wide transcription analysis facilitates our understanding of the formation of the storage root and deciphers key genes for further cassava improvement. Fibrous roots (FR), developing storage roots (DR) and mature storage roots (MR) were collected for RNA extractions from three independent healthy 4 month-old cassava (cultivar TMS60444) plants in the field .Two RNA samples extracted from stored storage root slices were used as technical repeats (TR) for quality control.
Project description:These experiments were to investigate changes in gene expression associated with maize competition for light when grown at double normal population density or under 60% shaded conditions as opposed to when maize is grown under normal field conditions.
Project description:microRNAs can play a crucial role in stress response in plants, including biotic stress. Some miRNAs are known to respond to bacterial infection. This work has addressed the role of miRNAs in Manihot esculenta (cassava)-Xanthomonas axonopodis pv. manihotis (Xam) interaction. Illumina sequencing was used for analyzing small RNA libraries from cassava tissue infected and non-infected with Xam. Cassava variety MBRA685 (resistant to Xam-CIO151) Six-week-old plants were inoculated with 36h-old cultures of the aggressive Xanthomonas axonopodis pv. manihotis strain CIO151 in both leaves and stems. Leaves were inoculated by piercing six holes in the mesophyll and placing a 5µL drop of a liquid Xam-MgCl2 culture calibrated at OD600nm = 0.002 (1 x108cfu/ml). Two leaflets per leaf and three leaves per plant were inoculated. Stems were inoculated by puncture in the stems as described previously (24). At least three plants per collection time were inoculated. Leaves and stems were collected from inoculated plants (0 hours post inoculation -hpi, 6hpi, 24hpi, 2 days post-inoculation -dpi, 5dpi, 7dpi and 15dpi) and non-inoculated plants. RNA extractions were made using a LiCl-acid phenol:chloroform method.
Project description:Rice (IR64) was grown in a field plot at the International Rice Research Institute in the Phillipines. This data shows transcriptional changes happening throughout the day in leaf tissue and how warm nighttime temperature may influence those transcriptional changes.
Project description:A IR64 variety of rice was grown in a field plot at the International Rice Research Institute (IRRI) in the Philippines. The data ganied from the expremint provides infromation of the daily trnascriptional changes occur in panicle tissue during an important developmental period.