PAP90, a novel rice protein plays a critical role in regulation of D1 protein stability of PSII.
J Adv Res 2021;
30:197-211. [PMID:
34026296 PMCID:
PMC8132209 DOI:
10.1016/j.jare.2020.11.008]
[Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/29/2020] [Accepted: 11/17/2020] [Indexed: 01/24/2023] Open
Abstract
Introduction
Photosystem II (PSII) protein complex plays an essential role in the entire photosynthesis process. Various known and unknown protein factors are involved in the dynamics of the PSII complex that need to be characterized in crop plants for enhancing photosynthesis efficiency and productivity.
Objectives
The experiments were conducted to decipher the regulatory proteins involved in PSII dynamics of rice crop.
Methods
A novel rice regulatory protein PAP90 (PSII auxiliary protein ~90 kDa) was characterized by generating a loss-of-function mutant pap90. The mutation was characterized at molecular level followed by various experiments to analyze the morphological, physiological and biochemical processes of mutant under control and abiotic stresses.
Results
The pap90 mutant showed reduced photosynthesis due to D1 protein instability that subsequently causes inadequate accumulation of thylakoid membrane complexes, especially PSII and decreases PSII functional efficiency. Expression of OsFtsH family genes and proteins were induced in the mutant, which are known to play a key role in D1 protein degradation and turnover. The reduced D1 protein accumulation in the mutant increased the production of reactive oxygen species (ROS). The accumulation of ROS along with the increased activity of antioxidant enzymes and induced expression of stress-associated genes and proteins in pap90 mutant contributed to its water-limited stress tolerance ability.
Conclusion
We propose that PAP90 is a key auxiliary protein that interacts with D1 protein and maintains its stability, thereby promoting subsequent assembly of the PSII and associated membrane complexes.
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