水稻灌浆相关转录因子基因OsNAC26的克隆与功能初步分析

Cloning and Functional Analysis of Os NA C26,A Grain Filling Related NAC Transcription Factor Gene from Rice

籽粒灌浆是水稻等谷类作物最重要的生理过程之一,直接影响稻米的产量和品质。本研究通过对水稻弱势粒灌浆相关转录因子OsNAC26进行表达分析,结果发现该基因在水稻籽粒灌浆及种子萌发时期高表达。此外,本研究还对OsNAC26进行了克隆和初步功能验证,结果显示OsNAC26的过量表达使水稻株高变矮,粒长粒宽降低,粒重降低;相反,OsNAC26突变则造成水稻株高增长,粒长粒宽增加,粒重提高。通过转录组关联分析,发现OsNAC26与种子储存蛋白及淀粉合成基因的表达高度相关。通过水稻原生质体转化及双荧光素酶报告实验,发现OsNAC26能够直接激活种子储存蛋白合成基因的表达。这些结果证明OsNAC26不仅参与了水稻籽粒灌浆调控,并且参与调控水稻株高以及粒型的调控,对研究水稻灌浆生理与分子机理和培育高产水稻新品种具有一定的理论指导意义和实践意义。

Grain filling is one of the most important biological processes in cereal crops,which determines the final yield and grain quality of rice.To characterize the function of transcription factor OsNAC26,which was reported to be involved in grain flling of inferior grain,the overexpression lines and CRISPR/Cas9 knock-out mutant of OsNAC26 were generated.The qPCR results demonstrated that OsNA C26 was highly and specifically expressed in seeds of germination stage and grain flling stage.On the other hands,overexpression of OsNAC26 resulted in reduced plant height,grain length,grain width and grain weight.While mutation of OsNAC26 promoted the plant height,grain length,grain width and grain weight in rice.By transcriptomic analysis,the expression of OsNAC26 was found to be co-expressed with seed storage protein and starch synthesis genes.The dual-luciferase reporter assay in rice protoplasts demonstrated that OsNAC26 could directly activate the expression of genes related with seed storage protein biosynthesis.Our results suggest OsNAC26 not only plays an important role in grain filling regulation,but also regulates plant height and grain size in rice,which has certain theoretical and practical significance for the study of rice flling physiology and molecular mechanism and the cultivation of new high-yield rice varieties.