Physiological and transcriptomic analysis of antioxidant mechanisms in sweet sorghum seedling leaves in response to single and combined drought and salinity stress

• Published in: Journal of plant interactions Vol. 17; no. 1; pp. 1006 - 1016
• Main Authors: Wang, Zhiheng, Wei, Yuqing
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 31.12.2022; Taylor & Francis Ltd; Taylor & Francis Group
• Subjects: Abbreviations; Accumulation; antioxidant mechanisms; Antioxidants; Ascorbic acid; Carbon dioxide; Carbon dioxide concentration; Catalase; Cell death; Chlorophyll; Combined stress; Damage; Drought; Electron transport; Energy conversion; Energy conversion efficiency; Gene expression; Gene sequencing; Genes; Glutathione; Glutathione peroxidase; Glutathione reductase; Hydrogen peroxide; Hydroxyl radicals; L-Ascorbate peroxidase; Leaves; Membrane permeability; Moisture content; Oxidative stress; Photochemicals; Photosynthesis; Polyethylene glycol; Principal components analysis; Reactive oxygen species; RNA-Seq; Salinity; Salinity effects; Seedlings; Sorghum; Stomata; Stomatal conductance; Superoxide anions; Superoxide dismutase; Sweet sorghum; transcriptomics; Transpiration; Water content
• ISSN: 1742-9145; 1742-9153
• DOI: 10.1080/17429145.2022.2146771

The effects of drought, salinity, and combined stress on ROS and ROS metabolic physiology and transcriptomics in sweet sorghum seedling leaves were evaluated. The results showed that drought stress had little effect on photosynthesis, while the SOD activity, CAT activity, and the expression of their related genes were elevated in leaves, but no excessive accumulation of O 2 - , H 2 O 2 , or -OH was observed. Under salinity stress, photosynthesis was inhibited, the O 2 - , H 2 O 2 and -OH contents increased significantly, and the SOD, POD, CAT activities and the expression of their related genes in leaves were elevated. Under combined stress, photosynthesis was significantly inhibited, the highest accumulation of O 2 - , H 2 O 2 and -OH contents occurred, and the SOD and POD activities and the expression of related genes in leaves were significantly increased, but the CAT was significantly decreased. These results collectively indicate that oxidative damage to sweet sorghum seedling leaves was higher with combined stress than with either drought or salinity stress alone. Under combined stress the SOD and POD activities were increased, but the CAT activity in the AsA-GSH cycle was severely reduced, demonstrating that antioxidant mechanisms in seedlings did not play a normal protective role, leaving the plants severely damaged by oxidative stress. Abbreviations: AsA: Ascorbic acid; APX: Ascorbate peroxidase; CAT: Catalase; Chl a: Chlorophyll a; Chl b: Chlorophyll b; Ci: Intercellular CO2 concentration; DHAR: Dehydroascorbate reductase; DEGs: Differentially expressed genes; DW: Dry weight; ETR: Photosynthetic electron transport rate; FW: Fresh weight; Fv/Fm: Original light energy conversion efficiency; GPX: Glutathione peroxidase; GR: Glutathione reductase; Gs: Stomatal conductance; GSH: Oxidized glutathione; H2O2: Hydrogen peroxide; MDA: Malondialdehyde; MDHAR: Monodehydroascorbate reductase; O2-: Superoxide anion; PCA: Principal component analysis; PCD: Programed cell death; PEG-6000: Polyethylene glycol 6000; POD: Peroxidase; Pn: Photosynthetic rate; Pro: Proline; qRT-PCR: Quantitative real-time PCR; RNA-seq: RNA Sequencing; ROS: Reactive oxygen species; RWC: Relative water content; RMP: Relative membrane permeability; SOD: Superoxide dismutase; SW: Saturation weight; Tr: Transpiration rate; ΦPSII: Actual photochemical efficiency; -OH: Hydroxyl radical