A <it>var2 </it>leaf variegation suppressor locus, <it>SUPPRESSOR OF VARIEGATION3</it>, encodes a putative chloroplast translation elongation factor that is important for chloroplast development in the cold

• Main Authors: Yu Fei, Rodermel Steve R, Liu Xiayan
• Format: Article
• Language: English
• Published: BMC 2010-12-01
• Series: BMC Plant Biology
• Online Access: http://www.biomedcentral.com/1471-2229/10/287

<p>Abstract</p> <p>Background</p> <p>The Arabidopsis <it>var2 </it>mutant displays a unique green and white/yellow leaf variegation phenotype and lacks VAR2, a chloroplast FtsH metalloprotease. We are characterizing second-site <it>var2 </it>genetic suppressors as means to better understand VAR2 function and to study the regulation of chloroplast biogenesis.</p> <p>Results</p> <p>In this report, we show that the suppression of <it>var2 </it>variegation in suppressor line <it>TAG-11 </it>is due to the disruption of the <it>SUPPRESSOR OF VARIEGATION3 </it>(<it>SVR3</it>) gene, encoding a putative TypA-like translation elongation factor. SVR3 is targeted to the chloroplast and <it>svr3 </it>single mutants have uniformly pale green leaves at 22°C. Consistent with this phenotype, most chloroplast proteins and rRNA species in <it>svr3 </it>have close to normal accumulation profiles, with the notable exception of the Photosystem II reaction center D1 protein, which is present at greatly reduced levels. When <it>svr3 </it>is challenged with chilling temperature (8°C), it develops a pronounced chlorosis that is accompanied by abnormal chloroplast rRNA processing and chloroplast protein accumulation. Double mutant analysis indicates a possible synergistic interaction between <it>svr3 </it>and <it>svr7</it>, which is defective in a chloroplast pentatricopeptide repeat (PPR) protein.</p> <p>Conclusions</p> <p>Our findings, on one hand, reinforce the strong genetic link between VAR2 and chloroplast translation, and on the other hand, point to a critical role of SVR3, and possibly some aspects of chloroplast translation, in the response of plants to chilling stress.</p>