Chen Wei, Sheng Zhonghua, Cai Yicong, Li Qianlong, Wei Xiangjin, Xie Lihong, Jiao Guiai, Shao Gaoneng, Tang Shaoqing, Wang Jianlong, Hu Peisong
State Key Laboratory of Rice Biology, Key Laboratory of Rice Biology and Genetic Breeding of Ministry of Agriculture, China National Rice Research Institute, Hangzhou, China.
The Collaborative Innovation Center of Southern Grain and Oil Crops, Agricultural College of Hunan Agricultural University, Changsha, China.
Front Plant Sci. 2019 Feb 19;10:175. doi: 10.3389/fpls.2019.00175. eCollection 2019.
Rice yield is closely related to plant leaf shape and chlorophyll content. In this study, we isolated and identified a narrow and rolled leaf mutant, temporarily named with darker green leaves. Histological analysis showed that has a reduced number of vascular bundles and undergoes abnormal abaxial sclerenchymatous cell differentiation. The mutant phenotype was controlled by a single recessive gene, fine-mapped to a 221 kb interval between Indel3 and RM2322 on Chr3. There are 42 ORF in this interval. Sequencing identified an SNP mutant leading to a premature stop in ORF 18, the candidate gene. Bioinformation analysis indicated that encodes a novel protein with unknown function. NRL3 is localized in cytoplasm, membrane and nucleus. Expression analysis of showed that genes involved in chlorophyll synthesis were significantly up-regulated while those involved in chlorophyll degradation and programmed cell death (PCD) were significantly down-regulated. The expression levels of photosynthesis genes were also affected. Y2H and BIFC assays indicated that NRL3 interacts directly with NAL9/VYL to regulate leaf morphology in rice. Thus, plays an important role in leaf morphogenesis and chlorophyll accumulation, and can be used as a new gene resource for constructing improved rice.
水稻产量与植株叶形和叶绿素含量密切相关。在本研究中，我们分离并鉴定了一个窄卷叶突变体，暂命名为深绿叶突变体。组织学分析表明，该突变体维管束数量减少，叶背厚壁细胞分化异常。该突变体表型受单个隐性基因控制，精细定位到第3号染色体上Indel3和RM2322之间的221 kb区间。此区间有42个开放阅读框（ORF）。测序鉴定出一个单核苷酸多态性（SNP）突变体，导致候选基因ORF 18提前终止。生物信息学分析表明，该基因编码一个功能未知的新蛋白。NRL3定位于细胞质、细胞膜和细胞核。对该基因的表达分析表明，参与叶绿素合成的基因显著上调，而参与叶绿素降解和程序性细胞死亡（PCD）的基因显著下调。光合作用相关基因的表达水平也受到影响。酵母双杂交（Y2H）和双分子荧光互补（BIFC）分析表明，NRL3直接与NAL9/VYL相互作用，调控水稻叶片形态。因此，NRL3在叶片形态建成和叶绿素积累中起重要作用，可作为改良水稻的新基因资源。
