Effects On The Growth Of Transgenic Rice With Overexpression Of HL-CMS Candidate Gene Orf216 And Tobacco Glycosyltransferase Gene Sm-Ngt1

Honglian cytoplasmic male sterility (HL-CMS) is one of the three major CMS types in rice (Oryza sativa L.) used in commercial production of hybrid rice. There are two described candidate genes, orfH79 and orf216, involved in HL-CMS, but their sterile-induced mechanisms are still unknown.Glycosyltransferases (GTs) are involved in the biosynthesis and modification of many substances, and it plays a critical role in the construction of organism cell, cell metabolism and regulation of life activities. In our laboratory, a new tobacco glycosyltransferase gene, sm-Ngt1, has been cloned. It is demonstrated that its expression could be dually induced by methyl jasmonate (MeJA) and salicylic acid (SA), but its physiological function in vivo is still unclear.In order to verify the function, the copy of orf216 in male sterile line YTA, maintainer line YTB, restorer line 9311, hybrid HL-2 and transgenic plant of orf216, and the expression analysis of HL-CMS candidates gene orf216 in RNA level were studied. On the other hand, the gene sm-Ngt1 which can lead to tobacco dwarf was transformed into the YTB (Oryza sativa L.) to see whether it can produce dwarf phenotype.1. Using the gene orf216 as a probe, Southern blot on DNA digested with different restriction enzymes of YTA, YTB, HL-2, 9311 and transgenic plants was carried out. It is demenstrated that a single copy of orf216 exists only in YTA, HL-2 and the positive transgenic plants.2. In order to study the expression of candidate gene orf216, Northern blot on RNA extracted from anther of YTA, YTB, HL-2 and 9311 was analyzed. It was showed that the orf216 expression was detected only in male sterile line YTA, and not in HL-2.3. By the ORF of sm-Ngt1 recombined pCAMBIA1305 vector, the sm-Ngt1 expression vector, PZ46, was constructed (Wang Zhuo, 2008). In this study, using PZ46 to tansform YTB by agrobacterium-mediated method, 130 positive transgenic rice plants with appearing different degrees of dwarf were obtained compared with the control of untransgenic plant YTB. Statistical data showed that the average height of transgenic plants with PZ46 is much lower than that of control plants of YTB and transgenic plants with pCAMBIA1305. Among transgenic plants with PZ46, there are 37% transgenic plants with height 71.4±9.8 cm , 27% with 65.1±4.6 cm, respectively; while the height of transgenic plants with pCAMBIA1305 is 114.1±5.2cm and control of YTB is 130.0±4.3 cm. It is certain that the over expression of glycosyltransferase gene can lead to the dwarf of rice plants.