State Key laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China.
Shandong Provincial Key Laboratory of Plant Stress, College of Life Science, Shandong Normal University, Jinan, 250014, China.
BMC Plant Biol. 2020 Apr 19;20(1):172. doi: 10.1186/s12870-020-02393-5.
Chloroplasts are essential organelles of plant cells for not only being the energy factory but also making plant cells adaptable to different environmental stimuli. The nuclear genome encodes most of the chloroplast proteins, among which a large percentage of membrane proteins have yet to be functionally characterized.
We report here functional characterization of two nuclear-encoded chloroplast proteins, Chloroplast protein for Growth and Fertility (CGF1) and CGF2. CGF1 and CGF2 are expressed in diverse tissues and developmental stages. Proteins they encode are associated with chloroplasts through a N-terminal chloroplast-targeting signal in green tissues but also located at plastids in roots and seeds. Mutants of CGF1 and CGF2 generated by CRISPR/Cas9 exhibited vegetative defects, including reduced leaf size, dwarfism, and abnormal cell death. CGF1 and CGF2 redundantly mediate female gametogenesis, likely by securing local energy supply. Indeed, mutations of both genes impaired chloroplast integrity whereas exogenous sucrose rescued the growth defects of the CGF double mutant.
This study reports that two nuclear-encoded chloroplast proteins, Chloroplast protein for Growth and Fertility (CGF1) and CGF2, play important roles in vegetative growth, in female gametogenesis, and in embryogenesis likely by mediating chloroplast integrity and development.
叶绿体是植物细胞的重要细胞器，不仅是能量工厂，还使植物细胞能够适应不同的环境刺激。核基因组编码大多数叶绿体蛋白，其中很大一部分膜蛋白尚未具有功能特征。
我们在此报告了两个核编码的叶绿体蛋白，叶绿体生长和育性蛋白（CGF1）和 CGF2 的功能特征。CGF1 和 CGF2 在不同的组织和发育阶段表达。它们编码的蛋白通过绿色组织中的 N 端叶绿体靶向信号与叶绿体相关，但也位于根和种子中的质体中。CRISPR/Cas9 产生的 CGF1 和 CGF2 突变体表现出生长缺陷，包括叶片变小、矮化和异常细胞死亡。CGF1 和 CGF2 冗余介导雌性配子体发生，可能通过确保局部能量供应。事实上，这两个基因的突变都损害了叶绿体的完整性，而外源性蔗糖则挽救了 CGF 双突变体的生长缺陷。
本研究报告称，两个核编码的叶绿体蛋白，叶绿体生长和育性蛋白（CGF1）和 CGF2，在营养生长、雌性配子体发生和胚胎发生中发挥重要作用，可能通过介导叶绿体的完整性和发育。
