Expression And Function Analysis Of ESP2, A Gene Involving Enclosed Panicle In Rice

The phenomenon of panicle enclosed generally exsist in indica rice males terile lines in rice production, which is mainly caused by the shortening of uppermost internode. Therefor, clone the gene related to the panicle enclosed and clarify its molecular mechanism will not only provide a theoretical basis for us to reduce or even completely remove the phenomenon of panicle enclosed but also a way to find a new rice germplasm. We found a new mutant of panicle enclosed named esp2(enclosed short panicle) from Minghui86by tissue cluture method. The ability of vegetative growth and fructification represented nomally. The results of genetical analysis showed that the mutant of panicle enclosed was a single recessive mutant, and we speculated ESP2is likely a key gene to control the development of the the uppermost internode. At present, our group have made a fine mapping and found a candidate gene named ESP2. On this basis, we anslysis the biological function and promoter sequences of ESP2by bioinformatics methods, and we also studied the expressional and functional features of ESP2by GUS transgenic plants and over-expressional of ESP2. The main results are as follows:(1) We make a predetermination about the biological function of ESP2by the bioinformatical analysis, and analysis the promoter sequences of ESP2. The results indicated that ESP2encodes a protein which has a high homology to the phosphatidylserine synthase, and it contains two transmembrane domains. So we supposed that ESP2may be a membrane protein. The gene which encode phosphatidylserine synthase exists in plants, animals and microorganisms, the main function of them is to catalyze the biosynthesis of phospholipids, while phospholipids are important components of membrane phospholipids on the cell metabolism,which take an inportant role to regulate the process of metabolism. We found two core promoter which were located in the domain of348bp-398bp and2780bp-2830bp in the upstream of ATG of ESP2by bioinformatics software of BDGP. Therefore, we chosed3570bp sequences as promoter of ESP2.(2) A GUS expression vector of pESP2:GUS was used to transform a japonica rice cultivar zhonghua15, and19transgenic plants were obtained. Staining results showed that expression signals of ESP2was detected in root, leaf, internode and spikelet, and strong expression signals of ESP2were detected at the uppermost internode and the internode of spikelet. But expression signals of ESP2were not detected in the stem apex at the vegetative growth phase. ESP2expression was also found in lemma/palea and anther a mature spikelet, but which was not found in faliment and lodicule.(3) An over-expression vector of Ubi:ESP2, was constructed and used to transform rice.27transgenic plants were obtained. real-time quantitative PCR analysis indicated that ESP2expression was significantly increased in transgenic plant. But the phenotype of the transgenic plants (To)was the same as that of wild type, so we will continue to observate and analysis the phenotype of transgenic plant progenies (T1) and no transgenic plant progenies.