Physiological, Biochemical, and Transcriptomic Analyses Reveal the Response to Oxidative Stress Under Drought Stress in Castor (Ricinus communis L.)
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. Overall design: RNA-seq analysis of castor roots under 15% PEG-6000 Stress for 3, 7, and 4 d (11 d) of rehydration.