Dense Panicle Related Gene Cloning from Rice Mutant A989 and Transgenic Plant Analysis

Flowering time and inflorescence architecture are important and inter-relating traits in rice (Oryza sativa L.). Overexpression of each of RCN1 to RCN3 in rice could result in delayed flowering and abnormal inflorescence architecture. From a transferred DNA (T-DNA) insertion population constructed from japonica rice cv. Zhonghua 11, a mutant, A989, exhibiting dense panicle and late flowering was isolated. Genetic and molecular analysis showed that a single copy of T-DNA was inserted into the genome of the mutant, and the T-DNA was inserted into the 330 bp position after RCN2 poly A. Overexpression of RCN2 was observed in the mutant as revealed by reverse transcription-polymerase chain reaction (RT-PCR) test. When RCN2 gene was transferred into wild type driven by double 35S promoters, the transformants showed no panicle due to the suspensions of differentiation and growth of the secondary-branch primordium; however, the transition from vegetative growth to productive growth was normal in the transgenic plant.

摘要从水稻T-DNA插入突变群体中分离得到一个密穗突变体A989, 表现晚开花、穗二级枝梗和小花数增加以及包颈。分子检测证明A989中T-DNA是单拷贝插入, 通过inverse PCR的方法分离得到A989中T-DNA的旁邻序列, 表明T-DNA插入在RCN2基因polyA加A位点后330 bp处; RT-PCR检测发现在A989中, RCN2基因的表达被显著上调。利用2×35S启动子在野生型水稻Zhonghua 11中超表达RCN2基因, 转基因植株表现为不抽穗, 通过细胞学观察发现转基因植株能完成营养生长向生殖生长的转变, 但是生殖生长期的分生组织在分化出二级枝梗原基后停止分化和生长。此外, 通过比较部分开花相关基因在野生型Zhonghua 11、突变体A989中的表达, 推测了RCN2基因可能的作用途径。