Project description:The aim of the project was to elucidate the inter-organellar interplay of plastids, mitochondria, and peroxisomes during storage reserve mobilization in the endosperm to supply the growing seedling with nutrients upon germination. Organelles from endosperm of etiolated castor bean seedlings were isolated and subjected to liquid chromatography-tandem mass spectrometry. The data were used to build a comprehensive metabolic model for plastids, mitochondria, and peroxisomes.
Project description:Small noncoding RNA (sncRNA), including microRNAs (miRNAs) and endogenous small-interfering RNAs (endo-siRNAs) are key gene regulators in eukaryotes, playing critical roles in plant development and stress tolerance. Trans-acting siRNAs (ta-siRNAs), which are secondary siRNAs triggered by miRNAs, and siRNAs from natural antisense transcripts (nat-siRNAs) are two well-studied classes of endo-siRNAs. In order to understand sncRNAs’ roles in plant cold response and stress acclimation, we studied miRNAs and endo-siRNAs in Cassava (Manihot esculenta), a major source of food for the world populations in tropical regions. Combining Next-Generation sequencing and computational and experimental analyses, we profiled and characterized sncRNA species and mRNA genes from the plants that experienced severe and moderate cold stresses, that underwent further severe cold stress after cold acclimation at moderate stress, and that grew under the normal condition. We also included Castor bean (Ricinus communis) to understand conservation of sncRNAs. In addition to known miRNAs, we identified dozens of novel miRNAs as well as ta-siRNA-yielding and nat-siRNA-yielding loci in Cassava and Castor bean, respectively. Among the expressed sncRNAs, many sncRNAs were differentially expressed under cold stresses. Our study provided the results on gene regulation by sncRNAs in cold acclimation of Euphorbiaceous plants and the role of sncRNA-mediated pathways affected by cold stress and stress acclimation in Cassava.
Project description:Small noncoding RNA (sncRNA), including microRNAs (miRNAs) and endogenous small-interfering RNAs (endo-siRNAs) are key gene regulators in eukaryotes, playing critical roles in plant development and stress tolerance. Trans-acting siRNAs (ta-siRNAs), which are secondary siRNAs triggered by miRNAs, and siRNAs from natural antisense transcripts (nat-siRNAs) are two well-studied classes of endo-siRNAs. In order to understand sncRNAsM-bM-^@M-^Y roles in plant cold response and stress acclimation, we studied miRNAs and endo-siRNAs in Cassava (Manihot esculenta), a major source of food for the world populations in tropical regions. Combining Next-Generation sequencing and computational and experimental analyses, we profiled and characterized sncRNA species and mRNA genes from the plants that experienced severe and moderate cold stresses, that underwent further severe cold stress after cold acclimation at moderate stress, and that grew under the normal condition. We also included Castor bean (Ricinus communis) to understand conservation of sncRNAs. In addition to known miRNAs, we identified dozens of novel miRNAs as well as ta-siRNA-yielding and nat-siRNA-yielding loci in Cassava and Castor bean, respectively. Among the expressed sncRNAs, many sncRNAs were differentially expressed under cold stresses. Our study provided the results on gene regulation by sncRNAs in cold acclimation of Euphorbiaceous plants and the role of sncRNA-mediated pathways affected by cold stress and stress acclimation in Cassava. Examination of small RNA populations in Cassava cultivar SC124 under the normal condition (NC), gradual cold acclimation (CA), cold shock (CS) and stress acclimation Cold stress after cold acclimation (CCA).
Project description:Castor is an important industrial raw material. Drought leads to delayed development and reduced yield of castor plants. However, the molecular mechanism of the response of castor plants to drought stress has not been determined. In this study, physiological, biochemical, and RNA-seq analyses were conducted on castor roots under PEG-6000 stress for 3, 7, and 4 d (11 d) of rehydration. The activities of GR, APX, SOD, and CAT in the roots of the castor plants under PEG-6000 stress increased at 3 d and decreased at 7 d, while the activity of POD continued to increase. A total of 2926, 1507, and 111 DEGs were identified in castor roots stressed with PEG-6000 for 3 d and 7 d and rehydrated for 4 d (11 d), respectively. GO analysis revealed that antioxidant activity was significantly enriched under PEG stress. In addition, KEGG enrichment analysis revealed that the DEGs were significantly involved in glutathione metabolism, fatty acid metabolism, and plant hormone signal transduction. KEGG combined with WGCNA was used to screen two drought stress-related genes, PP2C39 and GA2ox4. We propose an oxidative stress model for castor plants under drought stress based on GO terms, KEGG pathway, and WGNA analyses. This study identified high-quality genes for the genetic and molecular breeding of drought-resistant castor beans.
Project description:Early planting is one of the strategies used to increase grain yield in temperate regions. However, poor cold tolerance in castor inhibits seed germination, resulting in lower seedling emergence and biomass. To date, proteomics studies have identified diverse proteins associated with germinating or developing castor seeds; however, the regulators involved in early imbibed castor seeds under cold stress are rare. Here, the elite castor variety Tongbi 5 was used to identify the differential abundance protein species (DAPS) between cold stress (4 °C) and control conditions (30 °C ) imbibed seeds. As a result, 127 proteins were identified to be differentially accumulated according to iTRAQ strategy. Bioinformatics analyses revealed that 84 DAPS were annotated in 24 GO functional groups, 70 DAPS were classified into 16 COG categories, and 56 DAPS were involved in 16 KEGG pathways. Based on physiological index assays and iTRAQ results, this study provided some invaluable insights into the cold stress responses of early imbibed castor seeds.
Project description:A wide range of environmental stresses lead to an elevated production of reactive oxygen species (ROS) in plant cells thus resulting in oxidative stress. The biological nitrogen fixation in the legume - Rhizobium symbiosis is at high risk of damage from oxidative stress. Common bean (Phaseolus vulgaris) active nodules exposed to the herbicide Paraquat (1,1 '-Dimethyl-4, 4'-bipyridinium dichloride hydrate) that generates ROS accumulation, showed a reduced nitrogenase activity and ureide content. We analyzed the global gene response of stressed nodules using the Bean CombiMatrix Custom Array 90K, that includes probes from some 30,000 expressed sequence tags (EST). A total of 4,280 ESTs were differentially expressed in oxidative stressed bean nodules; of these 2,218 were repressed. These genes were grouped in 44 different biological processes as defined by Gene Onthology. Analysis with the PathExpress bioinformatic tool, adapted for bean, identified five significantly repressed metabolic path This work presents the transcriptional profile of bean nodules, induced by strain Rhizobium tropici CIAT 899, under oxidative stress, generated experimentally by adding the herbicide Paraquat (1,1 '-Dimethyl-4, 4'-bipyridinium dichloride hydrate) for 48 hours. We analyzed the transcript profile, via microarray hybridization, using the Bean CombiMatrix Custom Array 90K, that includes probes from some 30,000 expressed sequence tags (EST). A total of 4,280 ESTs were differentially expressed in oxidative stressed bean nodules; of these 2,218 were repressed.