AtACDO1, an ABC1-like kinase gene, is involved in chlorophyll degradation and the response to photooxidative stress in Arabidopsis

• Published in: Journal of experimental botany 2012-06, Vol.63 (10), p.3959-3973
• Main Authors: Yang, Songguang, Zeng, Xueqin, Li, Tao, Liu, Ming, Zhang, Shengchun, Gao, Sujuan, Wang, Yaqin, Peng, Changliang, Li, Ling, Yang, Chengwei
• Format: Article
• Language: English
• Subjects: Arabidopsis; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - radiation effects; Biological and medical sciences; carotenoids; chlorophyll; Chlorophyll - metabolism; Chlorophyllides - metabolism; Chloroplast Proteins - genetics; Chloroplast Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant; genes; leaves; Light; oxidative stress; Oxidative Stress - radiation effects; paraquat; Plant physiology and development; Protein Kinases - genetics; Protein Kinases - metabolism; proteins; RNA interference; stress response; thylakoids
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/ers072

ABC1 (activity of bc1 complex) is a newly discovered atypical kinase in plants. Here, it is reported that an ABC1 protein kinase-encoded gene, AtACDO1 (ABC1-like kinase related to chlorophyll degradation and oxidative stress), located in chloroplasts, was up-regulated by methyl viologen (MV) treatment. AtACDO1 RNAi (RNA interference) plants showed developmental defects, including yellow-green leaves and reduced contents of carotenoids and chlorophyll; the chlorophyll reduction was associated with a change in the numbers of chlorophyll-binding proteins of the photosynthetic complexes. Chlorophyllide (Chlide) a the first product of chlorophyll degradation, and pheophorbide a, a subsequent intermediate of Chlide a degradation, were increased in AtACDO1 RNAi plants. The AtACDO1 RNAi plants were more sensitive to high light and MV than wild-type plants. The AtACDO1 RNAi plants had lower transcript levels of the oxidative stress response genes FSD1, CSD1, CAT1, and UTG71C1 after MV treatment compared with wild-type or 35S::AtACDO1 plants. Taken together, the results suggest that the chloroplast AtACDO1 protein plays important roles in mediating chlorophyll degradation and maintaining the number of chlorophyll-binding photosynthetic thylakoid membranes, as well as in the photooxidative stress response.