The C2H2 zinc-finger protein LACKING RUDIMENTARY GLUME 1 regulates spikelet development in rice  

C2H2锌指蛋白LRG1调控水稻小穗的发育

作　　者：Qiankun Xu Haiping Yu Saisai Xia Yuanjiang Cui Xiaoqi Yu He Liu Dali Zeng Jiang Hu Qiang Zhang Zhenyu Gao Guangheng Zhang Li Zhu Lan Shen Longbiao Guo Yuchun Rao Qian Qian Deyong Ren 徐乾坤;余海平;夏赛赛;崔元江;俞晓琦;刘贺;曾大力;胡江;张强;高振宇;张光恒;朱丽;沈兰;郭龙彪;饶玉春;钱前;任德勇(State Key Lab of Rice Biology,China National Rice Research Institute,Hangzhou 310006,China;College of Chemistry and Life Sciences,Zhejiang Normal University,Jinhua 321004,China)

机构地区：[1]State Key Lab of Rice Biology,China National Rice Research Institute,Hangzhou 310006,China [2]College of Chemistry and Life Sciences,Zhejiang Normal University,Jinhua 321004,China

出　　处：《Science Bulletin》2020年第9期753-764,M0004,共13页科学通报（英文版）

基　　金：supported by the Zhejiang Natural Science Foundation(LY18C130007);the National Natural Science Foundation of China(91735304);the Central Public-interest Scientific Institution Basal Research Fund of China National Rice Research Institute(2017RG001-4);the National Science and Technology Major Project(2016ZX08009003-003-008)。

摘　　要：Rice(Oryza sativa)spikelets are a unique inflorescence structure and their development directly determines grain size and yield.Although many genes related to spikelet development have been reported,the molecular mechanisms underlying this process have not been fully elucidated.In this study,we identified a new recessive rice mutant,lacking rudimentary glume 1(lrg1).The lrg1 spikelets only formed one rudimentary glume,which,along with the sterile lemmas,was homeotically transformed into lemma-like organs and acquired lemma identity.The transition from the spikelet to the floral meristem was delayed in the lrg1 mutant,resulting in the formation of an ectopic lemma-like organ between the sterile lemma and the terminal floret.In addition,we found that the abnormal lrg1 grain phenotype resulted from the alteration of cell numbers and the hull size.LRG1 encodes a ZOS4-06-C2H2 zinc-finger protein with the typical EAR motifs,and is expressed in all organs and tissues.LRG1 localizes to the nucleus and can interact with the TOPLESS-RELATED PROTEINs(TPRs)to repress the expressions of their downstream target genes.Taken together,our results reveal that LRG1 plays an important role in the regulation of spikelet organ identity and grain size.水稻小穗是一种独特的花序结构,其发育直接决定种子的大小和产量.一个正常的水稻小穗包含一个可育小花(1个外稃、1个内稃、2个浆片、6个雄蕊和1个雌蕊)、一对护颖及一对副护颖.通过EMS诱变,本研究分离得到了一个新的隐性水稻小穗突变体lacking rudimentary glume 1(lrg1).lrg1的小穗仅仅只有一个副护颖,且其与护颖一起被同源转化为外稃状器官.细胞学和分子生物学研究发现,LRG1基因在水稻小穗副护颖中显著表达,证明了LRG1是副护颖的特征基因.此外,lrg1突变体谷粒表型异常是由颖壳细胞数目和大小决定的,说明LRG1还参与调控谷粒大小.进一步的实验发现,LRG1基因编码的ZOS4-06-C2H2锌指结构转录因子可能是与TPRs蛋白相互作用来抑制下游基因表达.本研究一方面证实了副护颖、护颖和外稃是同源器官,另一方面LRG1基因参与调控种子大小,为分子设计育种提供了新的基因资源.

关 键 词：Rice(Oryza sativa) LRG1 Rudimentary glume Sterile lemma Grain size Spikelet determinacy 

分 类 号：S511[农业科学—作物学]