Redox Metabolism Stimulation in Bioethanol Sorghum Under Water Deficit Stress

Abstract

Rainfed conditions affect sorghum’s different growth stages and result in reduced biomass yield. In the present investigation, influence of water deficit stress on redox metabolism was studied in two BMR (CSV 43 and SPV 2017) and two non-BMR (CSV 15 and SPV 462) sorghum genotypes at 45, 55, 65, and 75 days after sowing (DAS). The membrane stability index i.e., malondialdehyde (MDA), antioxidative enzymes, total antioxidant potential, phenylalanine ammonia lyase (PAL), tyrosine ammonia lyase (TAL), polyphenol oxidase(PPO), and phenolic compounds were studied under rainfed conditions that created water deficit stress. Higher SOD, POX, CAT, and total antioxidant potential (FRAP, DPPH, TRP, and HFRS) were observed under rainfed conditions with lower H₂O₂ and MDA content in BMR genotypes over the non-BMR genotypes. Rainfed conditions increased the PAL, TAL activity, and phenolic compounds in BMR genotypes compared to non-BMR genotypes. The redox homeostasis was well established during the stress in BMR genotypes (CSV 43 and SPV 2017) compared to non-BMR sorghum genotypes (CSV 15 and SPV 462) by maintaining higher antioxidants counteracting the negative impact of rainfed conditions, and therefore, scrutiny of present data indicates that BMR sorghum, that is now-a-days used mostly for bioethanol production, may perform better under water deficit conditions.