Net photosynthesis acclimates to low growth temperature in cotton seedlings by shifting temperature thresholds for photosynthetic component processes and respiration

Authors: SNIDER, JOHN - University Of Georgia; PILON, CHRISTIANE - University Of Georgia; HU, WEI - Nanjing Agricultural University; WANG, HAI-MIAO - Nanjing Agricultural University; TISHCHENKO, VICTOR - University Of Georgia; SLATON, WILLIAM - University Of Central Arkansas; Chastain, Daryl; PARKASH, VED - University Of Georgia

Submitted to: Environmental and Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2022
Publication Date: 2/4/2022
Publication URL: https://handle.nal.usda.gov/10113/7671032
Citation: Snider, J., Pilon, C., Hu, W., Wang, H., Tishchenko, V., Slaton, W., Chastain, D.R., Parkash, V. 2022. Net photosynthesis acclimates to low growth temperature in cotton seedlings by shifting temperature thresholds for photosynthetic component processes and respiration. Environmental and Experimental Botany. 196:104816. https://doi.org/10.1016/j.envexpbot.2022.104816.
DOI: https://doi.org/10.1016/j.envexpbot.2022.104816

Interpretive Summary: Cotton is one of the most important and versatile crops in the world, but it suffers from exceptional sensitivity to low temperature in the seedling phase. Information on photosynthetic cold acclimation in cotton is extremely limited and studies defining the relative cold sensitivity of photosynthetic component processes are essentially non-existent. The current manuscript reports that 1) some low temperature acclimation of net photosynthesis exists for cotton, primarily due to acclimation of mitochondrial respiration to under low growth temperature conditions and 2) that differences in cold sensitivity between different photosynthetic processes can lead to oxidative stress, thereby necessitating enhanced antioxidant enzyme activity and increased dissipation of excess energy during the light-dependent reactions of photosynthesis. This work essentially defines the weakest links in cotton’s photosynthetic response to low temperature, which will be extremely important for future efforts aimed at improving crop performance under sub-optimal early-season temperatures.

Technical Abstract: Temperatures between 10°C and 25°C substantially limit seedling growth and reversibly inhibit net assimilation (An) in cold-sensitive plants. Because An represents a number of component processes operating in a highly concerted manner, quantifying the cold sensitivities of each constituent would provide targets for improving cold tolerance. In the current study, Gossypium hirsutum (cotton) seedlings grown under sub-optimal temperatures exhibited substantial declines in plant growth, An, and nearly every thylakoid process assessed, relative to optimal conditions. In contrast, energy dissipation by photosystem II (PSII) increased under low temperature concomitant with a rise in carotenoid content, hydrogen peroxide production, and ascorbate peroxidase activity. Low temperature threshold experiments showed electron transport was more cold-sensitive than gross or net photosynthesis and acclimation of dark respiration (Rd) slightly enhanced cold tolerance of An for plants grown under low temperatures. [CO2] × temperature response experiments further revealed that carboxylation was more temperature sensitive than RuBP regeneration. It is concluded that 1) low temperature acclimation of An exists for G. hirsutum, primarily due to plasticity of Rd to growth temperature and 2) differences in cold sensitivity between carboxylation and RuBP regeneration favor reactive oxygen species production, thereby necessitating enhanced ROS scavenging and upstream energy dissipation by PSII.