Light is an important signal in the growth and development of plants, and it is one of the elements of photosynthesis. However, the phenomenon of photoinhibition in plants under strong light is mainly due to the damage of the D1 protein in the photosystem II (PSII) and photosynthesis. At the same time, plants have evolved a mechanism to repair damaged D1 protein. The main function of FtsH protease is to degrade and clear damaged D1 protein in time. Although the FtsH2 gene has been studied in the model plant Arabidopsis thaliana, the function of the FtsH2 gene in crops is not yet clear.
The research group of Xia Zhengjun, a researcher at the Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, published a research paper entitled A critical role of PvFtsH2 in the degradation of photodamaged D1 protein in common bean on Horticulture Research. The study used the Chinese kidney bean variety”Dalong No. 1″ as the background material, and found a seedling lethal pvsl1 mutant in the mutant material created by 60Co radiation. The mutant died within 2 weeks in the field or under high light intensity after emergence; in the greenhouse Under medium and low light intensities, the chlorosis phenotype appears, and it can bloom and bear fruit normally. The PvSL1 candidate gene was located in the 53.7 kb region of chromosome 2 by INDEL molecular markers. The CDS region of the candidate gene Phvul.002G190900 was deleted by 1 bp in the pvsl1 mutant, which resulted in the early termination of protein translation. The expression of Phvul.002G190900 gene (PvFtsH2) was up-regulated with increasing light intensity, and its expression was significantly down-regulated in the pvsl1 mutant. The loss of PvFtsH2 protein function in the pvsl1 mutant caused the damaged D1 protein under high light intensity to not be degraded and cleared in time, causing irreversible damage to PSⅡ, reducing the photosynthesis capacity and the death of leaf cells, which led to the overall death of the plant. In the pvsl1 mutant, the expression levels of PvFtsH5 and PvFtsH8 were up-regulated, suggesting that other FtsH family members also have the ability to partially compensate for the degradation of PvFtsH2 to remove the light-damaged D1 protein, so that the pvsl1 mutant can complete vegetative growth under low light intensity. The study revealed that the PvFtsH2 protein plays an important role in ensuring the normal operation of the kidney bean photosynthetic system under strong light.
Northeast Geography Institute Special Research Assistant Xu Kun is the first author of the paper, and Xia Zhengjun is the corresponding author of the paper. The research work has been funded by national key research and development projects and the National Natural Science Foundation of China.
Phaseolus vulgaris PvFtsH2 protein degradation and light damage D1 protein model