水稻窄叶突变体zy17的遗传分析和候选基因鉴定

器官大小调控是一个基本的发育生物学过程,受细胞分裂和细胞扩展的影响。然而,植物器官大小调控的遗传和分子机理仍不清楚。为了进一步了解器官大小调控的分子机制,文章分离了一系列水稻叶子宽窄改变的突变体。其中,窄叶突变体zy17叶变窄,同时伴有植株矮化、穗子变小、枝梗数和穗粒数降低的表型。遗传分析表明该窄叶性状受1个隐性基因控制;细胞学分析表明该突变体叶子的细胞数目和维管束数目显著降低,表明ZY17影响了细胞分裂。基因组重测序进一步筛选出ZY17的3个候选基因：Os02g22390基因突变发生在内含子区,编码蛋白为逆转座蛋白;Os02g28280和Os02g29530基因突变都发生在外显子区,其中Os02g28280编码一个功能未知蛋白,该基因突变后,发生碱基置换,产生非同义突变;Os02g29530编码一个含糖基转移酶相关的PFAM结构域的蛋白,该基因突变后,出现两个碱基的缺失,从而导致其蛋白翻译提前终止。对候选基因的深入研究,将揭示水稻叶子大小调控的机制。

Genetic analysis and identification of candidate genes for a narrow leaf mutant (zy17) in rice

Control of organ size by cell proliferation and cell expansion is a fundamental process in plant development, but little is known about the genetic and molecular mechanisms that determine organ size in plants. To understand the genetic and molecular mechanisms of organ growth control, we isolate a set of mutants with altered leaf size and identify the narrow leaf mutant, zhaiye 17 (zy17) (zhaiye means narrow leaf in Chinese). zy17 exhibits narrow leaves, slightly short plants, small panicles, reduced panicle branches and decreased grain numbers per panicle compared with the wild type. Our cytological analyses show that the narrow leaf phenotype of zy17 is caused by the reduced number of cells, indicating that ZY17 regulates cell proliferation. Genetic analyses show that the zy17 mutant phenotypes are controlled by a single gene. Using the whole genome resequencing approach and linkage analysis, we identify Os02g22390, Os02g28280 and Os02g29530 as candidate genes. Os02g22390 encodes a retrotransposon protein with the mutation occurring in the intronic region; Os02g28280 encodes a protein with unknown function with a base substitution resulting in non-synonymous mutation; Os02g29530 encodes a protein containing the PFAM domain related to glycosyltransferase, with a 2 bp deletion mutation causing a premature termination. Further studies on these three candidate genes will be helpful for understanding the molecular mechanism of organ size control in rice.