Activation of gibberellin 2-oxidase 6 decreases active gibberellin levels and creates a dominant semi-dwarf phenotype in rice (Oryza sativa L.)

作     者：Jian Huang Ding Tang Yi Shen Baoxiang Qin Lilan Hong Aiqing You Ming Li Xin Wang Hengxiu Yu Minghong Gu Zhukuan Cheng 

作者机构：State Key Laboratory of Plant Genomics and Center for Plant Gene ResearchInstitute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China Key Laboratory of Plant Functional Genomics of Ministry of EducationYangzhou UniversityYangzhou 225009China School of Basic Medicine & Biological SciencesSoochow UniversitySuzhou 215123China Food Crop Research InstituteHubei Academy of Agricultural ScienceWuhan 430064China 

出 版 物：《Journal of Genetics and Genomics》 (遗传学报（英文版）)

年 卷 期：2010年第37卷第1期

页      面：23-36页

核心收录：

学科分类：0710[理学-生物学] 1001[医学-基础医学(可授医学、理学学位)] 09[农学] 0901[农学-作物学] 0902[农学-园艺学] 090201[农学-果树学] 

基　　金：supported by grants from the Ministry of Sciences and Technology of China (No. 2005CB120805 and 2006AA10A101) the National Natural Science Foundation of China (No. 30621001 and 30871512) 

主　　题：GA 2-oxidase gibberellin biosynthesis dwarf rice 

摘      要：Gibberellin （GA） 2-oxidase plays a key role in the GA catabolic pathway through 2β-hydroxylation.In the present study,we isolated a CaMV 35S-enhancer activation tagged mutant,H032.This mutant exhibited a dominant dwarf and GA-deficient phenotype,with a final stature that was less than half of its wild-type counterpart.The endogenous bioactive GAs are markedly decreased in the H032 mutant,and application of bioactive GAs （GA3 or GA4） can reverse the dwarf phenotype.The integrated T-DNA was detected 12.8 kb upstream of the OsGA2ox6 in the H032 genome by TAIL-PCR.An increased level of OsGA2ox6 mRNA was detected at a high level in the H032 mutant,which might be due to the enhancer role of the CaMV 35S promoter.RNAi and ectopic expression analysis of OsGA2ox6 indicated that the dwarf trait and the decreased levels of bioactive GAs in the H032 mutant were a result of the up-regulation of the OsGA2ox6 gene.BLASTP analysis revealed that OsGA2ox6 belongs to the class III of GA 2-oxidases,which is a novel type of GA2ox that uses C20-GAs （GA12 and/or GA53） as the substrates.Interestingly,we found that a GA biosynthesis inhibitor,paclobutrazol,positively regulated the OsGA2ox6 gene.Unlike the over-expression of OsGA2ox1,which led to a high rate of seed abortion,the H032 mutant retained normal flowering and seed production.These results indicate that OsGA2ox6 mainly affects plant stature,and the dominant dwarf trait of the H032 mutant can be used as an efficient dwarf resource in rice breeding.