Study Of PLA3 On Rice Seed Germination And Early Seedling Growth

Rice is the primary food crop in our country. ABA is one of the most important hormones in seed germination. PLASTOCHRON gene in rice regulates the rate of leaf initiation and the vegetative-reproductive phase change. The mutant pla3 was proved to be not sensitive to ABA during germination in previous research. To explore the roles of PLA3 in rice seed germination and interaction with ABA, our study was conducted on the rice materials including wild type, pla3, abll (mutant not sensitive to ABA),Gang 46B, and D84B. We have screened PLA3 mutant seeds, analyzed its phenotype, investigated the effects of PLA3 on rice seed germination and seedling growth and discussed the role of PLA3 with ABA during seed germination and hybrid rice seed production. Results are as follows:1. Screening and analyzing pla3 mutant:the embryo of pla3 mutant was larger than the wild type and sag under stereoscopic microscope, features with which was applied to sort out the mutant seeds. Besides, pla3 mutant was easy to germinate, but the seedling grew slowly with leaf malformation, multi-tillers and dwarf plant. The pla3 plant couldn’t turn to reproductive growth resulted in completely sterile.2. PLA3 modulates rice seed germination and seedling growth and is induced by ABA. We have analyzed the germination characteristics of G46B and D84B, ang found out that germination rate was 90% for G46B and 70% for D84B within 36h. Therefore, we identified G46B was easy to germinate and D84B was difficult to germinate. The expression PLA3 gene in G46B and D84B was analyzed during rice seed germination and seedling growth. It was found that the expression of PL A3 showed significant difference in rice with different germination rate. In addition, diastase activity and hormone content decreased under 2 μmol/L and 5μmol/L ABA treatments, while PLA3 expression increased. PLA3 gene expression in abll mutant,which is not sensitive to ABA, is significantly lower than wild type in early seedling. The preliminary research implied PLA3 associated with ABA signal transduction pathways. R9311 and R4163. PLA3 regulates the formation of hybrid rice pre-harvest sprouting (PHS). R9311 and R416 (male parent) crossed with Y58S and Ⅱ-32A (female parent) respectively to breed hybrid seeds Y Liangyou 1 and Ⅱ You 416. Those hybrid rice differ in PHS, that Y Liangyou 1 is susceptible to PHS and Ⅱ You 416 isn’t. The dynamic of phytohormone contents and expression of PLA3 have been detected in hybrid rice before seed harvest. The results showed that the contents of endogenous hormone IAA and ZR, GA1 in Y Liangyou 1 is higher than that in Ⅱ You 416, but ABA content and PLA3 expression is quite the contrary. However, the expression of PLA3 is higher in Ⅱ You 416. It was speculated that PLA3 may be induced to express by ABA to work in this process.In this paper, we have done the relavent experiment on the role of PLA 3 in rice seed germination and early seedling growth. The results showed that PLA3 involved in ABA signal transduction during rice seed germination, early seedling growth and rice spike germination, which is also provide a basis for the study of PLA3 gene function on rice seed germination, seedling growth and spike germination.