Functional Analysis Of AGL6-like Gene OsMADS17in Rice

Some researches have shown that AGL6genes play important roles in floral organ development in plant. There are two AGL6genes in rice, namely,OsMADS6and OsMADS17. The function of OsMADS6has been very clear. It regulates the development of carpel, stamen, lodicule, lemma and palea in rice. A few studies have shown that OsMADS17is expressed in floral meristem, lemma, palea, pulp film, pistil and receptacle, but its exact function is still not clear. In this study, the function and expression of OsMADS17were analyzed using the methods of RNAi, over-expression, GUS expression and semi-quantitative RT-PCR.The major results are as follows:(1) A GUS expression vector of OsMADS17, pCAMBIA1391T-OsMADS17, was constructed and used to transform three japonica rice cultivars Nipponbare, zhonghua-11and zhonghua-15. Twenty six transgenic plants were obtained. Floral organs were collected at different developmental stages and stained histochemically. The results showed that OsMADS17was not expressed in root, shoot apical meristem, leaf blade and leaf sheath, but strongly expressed in young panicle and the lemma, palea and pedicle of developing spikelets. In a mature spikelet, weak expression of OsMADS17was detected in all floral organs including lemma/palea, lodicule, stamen and carpel.(2) An over-expression vector of OsMADS17, Ubi:OsMADS17, was constructed and used to transform rice.42transgenic plants were obtained.13transgenic plants displayed spikelet abnormality, with axis significantly elongated and the development of lemma and palea obviously inhibited. Semi-quantitative RT-PCR analysis showed that OsMADS17expression was significantly increased in the spikelets of these plants.(3) An RNAi vector of OsMADSl7, pTCK303-OsMADS17, was constructed and used to transform rice.32transgenic plants were obtained. Semi-quantitative RT-PCR analysis showed that the expression of OsMADS17was reduced at different extent in the transgenic plants, but no obvious pheonotypic changes were observed in the floral organs of these plants.