叶片是水稻进行光合作用的重要器官，其大小与产量直接相关。迄今虽已定位克隆了一些水稻叶片大小相关基因，但是其调控的分子机制还有待进一步研究。我们的前期研究筛选到多个叶片大小改变的突变体，其中nal24是一个窄叶的突变体，Mutmap方法克隆其编码一个细胞核定位的含有PARP结构域的未知功能蛋白。与此同时，利用LCI、Co-IP和体外Pull-down实验证实NAL24与转录因子DST (DROUGHT AND SALT TOLERANCE)存在直接相互作用。而中花11背景下NAL24的 CRISPR水稻nal24叶片变窄，而DST的CRISPR水稻dst植株叶片变宽，穗子变大。这些结果初步表明NAL24和DST可能作用于相同的遗传途径参与水稻叶片大小的调控。我们将在前期研究基础上，拟从遗传、生化、分子、细胞等方面阐明这两个基因调控叶片大小的分子机制，并评价它们在提高水稻产量方面的应用潜力。

Rice (Oryza sativa L.) is one of the most important food crops in the world, and the leaf size and shape are key agronomic traits related with yield. Although several genes controlling leaf morphology have been isolated, the molecular networks that establish leaf morphology still remain to be studied. Our group has isolated a set of rice leaf morphology mutants. Among these, the narrow leaf 24 (nal24) mutant has narrower leaves than the wild type. By using Mutmap, we cloned a NAL24 gene encoding a unknown nuclear localized protein with a Poly(ADP-ribose)polymerase (PARP) domain. In addition, luciferase complementation imaging (LCI) assay, co-immunoprecipitation assay (Co-IP) and in vitro pull-down assay confirmed the direct interaction between NAL24 and DROUGHT AND SALT TOLERANCE (DST). It is worth noting that the nal24 loss of function mutant using CRISPR had narrow leaf, while dst loss of function mutant had wider leaf, both of which showed great yield potential. Thus, these preliminary studies revealed that NAL24 and DST might act on the same genetic pathway to regulate rice leaf size. In this proposal, we tend to use the methods including molecular biology, cell biology, biochemistry and genetics to analyze the genetic interactions between NAL24 and DST, validate the physical interaction between NAL24 and DST in rice, investigate expression pattern and subcellular localization of NAL24 and DST, test whether NAL24 poly(ADP-ribosyl)ates DST directly, characterize the cellular basis of NAL24 and DST in regulating leaf size, and measure the yield of mutants and overexpression lines of NAL24 and DST. Our study will elucidate the molecular mechanisms of NAL24 and DST in rice leaf size control, and also evaluate the potential of employing NAL24 and DST to increase rice yield.