Abstract:

【Objective】 Pre-harvest sprouting is a phenomenon that seeds germinate while still attached onto the maternal plants in the condition of cloudy and rainy weather, and is also a restrictive factor of hybrid rice production and seed propagation. The phenotype of rice pre-harvest sprouting is very similar to that of maize seed-specific vp1 mutant. VP1 gene is essential for seeds maturation and dormancy, and is also a key transcription factor of ABA signal transduction pathway. Thus, it is of great significance to effectively control the occurrence and hazard of hybrid rice pre-harvest sprouting. The aim of the current investigation is to dissect the biological function of homologous gene OsVP1 in Oryza sativa by using transgenic technology. 【Method】 To further elucidate the function of VP1, the RNA interference (RNAi) vector containing the sequence fragment of OsVP1 was constructed and introduced into rice cv. Nipponbare by Agrobacterium-mediated genetic transformation. 【Results】 Analysis of semi-quantitative RT-PCR revealed a distinct reduction of endogenous OsVP1 expression levels in RNAi transgenic lines compared with wild-type plants. Germination experiment showed that the percentage of geminated seeds from T1 transgenic plants was higher than that of wild-type plants. Under the different concentrations of abscisic acid (ABA) treatment, the inhibition of germination ratio of transgenic seeds was not significantly different when comparing with wild-type plants. Germination experiment of T2 panicles from transgenic plants showed more severe pre-harvest sprouting than wild-type plants. 【Conclusion】 RNA interference of OsVP1 gene can increase germination velocity of transgenic seeds and also lead to pre-harvest sprouting.

Key words: OsVP1, RNA interference, Agrobacterium, Oryza sativa