Exacerbation of drought-induced physiological and biochemical changes in leaves of < em > Pisum sativum < /em > upon restriction of COX and AOX pathways of mitochondrial oxidative electron transport

J Biosci. 2024;49:5.ABSTRACTDrought stress affects photosynthesis, leading to significant decrease in crop productivity. In the current study, the importance of the cytochrome oxidase (COX) and alternative oxidase (AOX) pathways of themitochondrial oxidative electron transport chain (mETC) for photosynthesis and reactive oxygen species (ROS) homeostasis was evaluated in the leaves of Pisum sativum plants exposed to drought stress for 3 days (D3), 6 days (D6), and 9 days (D9). While drought stress resulted in decreased CO2 assimilation rates, leaf stomatal conductance, transpiration, and leaf intercellular CO2 concentration in a stress-dependent manner, superimposition with mETC inhibitors, antimycin A (AA) and salicylhydroxamic acid (SHAM), aggravated the responses. Decreased chlorophyll content, photosynthesis, and RubisCO (RbcL) degradation during progressive drought and their aggravation upon AOX pathway restriction indicated the importance of the AOX pathway for photosynthetic activity. Compared with COX pathway inhibition, higher intracellular H2O2 and O2.- levels, and increased cell death upon restriction of the AOX pathway during D6 and D9 stress conditions correlating with the modulation in antioxidant enzyme activities, signify the essentiality of the AOX pathway for ROS maintenance at optimal levels. Further, increased AOX1a expression during D6 and D9 conditions along with increasedAOXprotein levels indicated the activation of theAOXpathway during drought stress. D...
Source: Journal of Biosciences - Category: Biomedical Science Authors: Source Type: research