White Leaf and Panicle 2, encoding a PEP-associated protein, is required for chloroplast biogenesis under heat stress in rice. (16th October 2017)

• Record Type: Journal Article
• Authors: Lv, Yusong; Shao, Gaoneng; Qiu, Jiehua; Jiao, Guiai; Sheng, Zhonghua; Xie, Lihong; Wu, Yawen; Tang, Shaoqing; Wei, Xiangjin; Hu, Peisong
• Is Part Of: Journal of experimental botany. Volume 68:Number 18(2017)
• Page Start: 5147
• Page End: 5160
• Publication Date: 2017-10-16
• Subjects: chloroplast biogenesis -- heat stress -- PEP-associated protein -- redox balance -- rice -- White Leaf and Panicle 2 -- WLP2; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/erx332
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract : WLP2, encoding a PEP-associated protein, and its paralog OsFLN2 can interact with OsTRXz to form a TRX-FLN regulatory module to protect chloroplast development from heat stress in rice. Abstract: The plastid-encoded RNA polymerase (PEP) plays an important role in the transcription machinery of mature chloroplasts, yet details of its function remain elusive in rice. Here, we identified a novel PEP-associated protein (PAP), WLP2, based on its two allelic white leaf and panicle mutants, wlp2s and wlp2w . The two mutants were albino lethal at high temperatures and showed decreased chlorophyll accumulation, abnormal chloroplast ultrastructure, and attenuated photosynthetic activity. Map-based cloning suggested that WLP2 encodes a putative pfkB-type carbohydrate kinase family protein, which is homologous to fructokinase-like 1 (AtFLN1) in Arabidopsis. WLP2 is mainly expressed in green tissues and its protein localizes in chloroplasts. Expression levels of PEP-encoded genes, chloroplast development genes and photosynthesis-related genes were compromised in wlp2 mutants, indicating that WLP2 is essential for normal chloroplast biogenesis. Moreover, WLP2 and its paralog OsFLN2 can physically interact with thioredoxin OsTRXz to form a TRX-FLN regulatory module, which not only regulates transcription of the PEP-encoded genes but also maintains the redox balance in chloroplasts under heat stress. Furthermore, the wlp2w mutant gene represents a potential advantage in enhancing seed purity and high-throughput breeding. Our results strongly indicate that WLP2 protects chloroplast development from heat stress via a TRX-FLN regulatory module in rice.