Impairment of peroxisomal APX and CAT activities increases protection of photosynthesis under oxidative stress
Fabricio E. L. Carvalho; Yugo Lima-Melo; Rachel H. V. Sousa; Marcia Margis-Pinheiro; Setsuko Komatsu; Joaquim A. G. Silveira; Vicente T. C. B. Alencar; Danilo M. Daloso
https://urn.fi/URN:NBN:fi-fe2021042720521
Tiivistelmä
Retrograde signalling pathways that are triggered by changes in cellular redox homeostasis remain poorly understood.
Transformed rice plants that are deficient in peroxisomal ascorbate peroxidase APX4 (OsAPX4-RNAi) are
known to exhibit more effective protection of photosynthesis against oxidative stress than controls when catalase
(CAT) is inhibited, but the mechanisms involved have not been characterized. An in-depth physiological and proteomics
analysis was therefore performed on OsAPX4-RNAi CAT-inhibited rice plants. Loss of APX4 function led to an
increased abundance of several proteins that are involved in essential metabolic pathways, possibly as a result of
increased tissue H2O2 levels. Higher photosynthetic activities observed in the OsAPX4-RNAi plants under CAT inhibition
were accompanied by higher levels of Rubisco, higher maximum rates of Rubisco carboxylation, and increased
photochemical efficiencies, together with large increases in photosynthesis-related proteins. Large increases were
also observed in the levels of proteins involved in the ascorbate/glutathione cycle and in other antioxidant-related
pathways, and these changes may be important in the protection of photosynthesis in the OsAPX4-RNAi plants. Large
increases in the abundance of proteins localized in the nuclei and mitochondria were also observed, together with
increased levels of proteins involved in important cellular pathways, particularly protein translation. Taken together,
the results show that OsAPX4-RNAi plants exhibit significant metabolic reprogramming, which incorporates a more
effective antioxidant response to protect photosynthesis under conditions of impaired CAT activity.
Kokoelmat
- Rinnakkaistallenteet [19207]