Genetic Interactions Reveal that Speci c Defects of Chloroplast Translation are Associated with the Suppression of var2-Mediated Leaf Variegation

作     者：Xiayan Liu Mengdi Zheng Rui Wang Ruijuan Wang Lijun An Steve R.Rodermel Fei Yu 

作者机构：State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences Northwest A&F University Department of Genetics Development and Cell Biology Iowa State University 

出 版 物：《Journal of Integrative Plant Biology》 (植物学报（英文版）)

年 卷 期：2013年第55卷第10期

页      面：979-993页

核心收录：

学科分类：0710[理学-生物学] 07[理学] 09[农学] 071007[理学-遗传学] 0901[农学-作物学] 0703[理学-化学] 0902[农学-园艺学] 090102[农学-作物遗传育种] 

基　　金：supported by funds from National Natural Science Foundation of China to F.Y. (31071073 31170219) and to X.L. (31100864) by Chinese Ministry of Education Program of New Century Excellent Talents in University (NCET 09 0657) to F.Y by funding to S.R. from the US Department of Energy Energy Biosciences panel (DE FG02 94ER20147) 

主　　题：Chloroplast ribosomal protein L24 chloroplast rRNA processing genetic suppressor leaf variegation var2. 

摘      要：Arabidopsis thaliana L. yellow variegated （var2） mutant is defective in a chloroplast FtsH family metalloprotease, AtFtsH2/VAR2, and displays an intriguing green and white leaf variegation. This unique var2-mediated leaf variegation offers a simple yet powerful tool for dissecting the genetic regulation of chloroplast development. Here, we report the isolation and characterization of a new var2 suppressor gene, SUPPRESSOR OF VARIEGA TION8 （SVR8）, which encodes a putative chloroplast ribosomal large subunit protein, L24. Mutations in SVR8 suppress var2 leaf variegation at ambient temperature and partially suppress the cold-induced chlorosis phenotype of var2. Loss of SVR8 causes unique chloroplast rRNA processing defects, particularly the 23S-4.5S dicistronic precursor. The recovery of the major abnormal processing site in svr823S-4.5S precursor indicate that it does not lie in the same position where SVR8/L24 binds on the ribosome. Surprisingly, we found that the loss of a chloroplast ribosomal small subunit protein, $21, results in aberrant chloroplast rRNA processing but not suppression of var2 variegation. These findings suggest that the disruption of specific aspects of chloroplast translation, rather than a general impairment in chloroplast translation, suppress var2variegation and the existence of complex genetic interactions in chloroplast development.