花生高油品系农大D666及其亲本油脂合成酰基转移酶基因的表达分析

Expression Analysis of Acyltransferase Genes Involved in Oil Biosynthesis in High-oil Peanut Line Nongda D666 and Parents

为了探讨农大D666含油量超亲遗传的分子机制,以及籽仁含油量与油脂合成酰基转移酶基因(GPAT9,LPAAT,DGAT1-2)表达水平的相关性,选取油脂积累的三个关键期R4、R5和R6期荚果的籽仁,进行荧光定量PCR检测,分析了高油品系农大D666及其亲本不同发育时期籽仁内三类酰基转移酶基因的表达量,结果表明:在检测的3个材料中属于B染色体组的GPAT9-B和DGAT1-2B表达量明显高于A染色体组的部分同源基因GPAT9-A和DGAT1-2A,属于A染色体组LPAAT-A表达量明显高于B染色体组的LPAAT-B。农大D666的3类酰基转移酶基因表达量随荚果发育时期变化的模式与两个亲本、以及两个亲本间存在差异。农大D666的GPAT9-A表达量不同发育时期籽仁间无差异,其余基因随着荚果发育表达量逐渐升高。在R6期籽仁中,农大D666的GPAT9-B、GPAT9、DGAT1-2A、DGAT1-2B、DGAT1-2表达量均极显著高于两个亲本品种。DGAT1-2和GPAT9、LPAAT表达量的比值与种子最终含油量存在明显正相关。在发育的花生种子油脂积累的过程中,DGAT1-2和GPAT9、LPAAT表达量需要维持一定的协调性才有利于油脂的积累,从本研究中可得出R5期DGAT1-2和GPAT9、LPAAT表达量之间协调性较好,有利于油脂的合成与积累。推测高油品系农大D666含油量高的原因与R5期DGAT1-2和GPAT9、LPAAT表达量的相对值大小及R6期GPAT9、DGAT1-2的高表达有关。

The use of the study was to investigate the mechanism of transgressive inheritance of oil content in Nongda D666 and the correlation between the oil content of peanut kernel and the differential expression of acyltransferase genes （GPA T9, LPAA T, DGA T1-2） which were related to oil synthesis. Three kernel developmental stages （R4, R5, R6） were sampled from high oil line Nongda D666 and its parents. The quantitative analysis of the three acyltransferase genes in kernel of high oil line Nongda D666 and its parents at different developmental stages was carded out by quantitative PCR assay. The results showed that the expression levels of GPA T9-B and DGA T1-2B in B genome were significantly higher than GPA T9-A and DGA T1-2A in A genome. The expression level ofLPAA T-A in A genome was significantly higher than LPAA T-B in the B genome. The expression pattern of acyltransferase genes in Nongda D666 was different from that in two parental cultivars. There was no significant difference in GPA T9-A expression among the different developmental stages. The expression of other genes increased gradually with the development of pods. The expression levels of GPA T9-B, GPA T9, DGA T1-2A, DGA T1-2B and DGA T1-2 in the R6 phase of peanut kernel were significantly higher than those of the two parental eultivars. The ratio of DGA T1-2, GPA T9 and LPAA T expression was positively correlated with the final oil content of seeds. In the process of seed oil synthesis in peanut, DGA T1-2, GPA T9 and LPAA T expression need to have a certain coordination in order to promote the accumulation of oil. From the present study, the coordination of DGA T1-2, GPA T9 and LPAA T in R5 stage was better, which was beneficial to the synthesis and accumulation of oil and fat. It was suggested that the high oil content of NongdaD666 was related to the relative value of DGA T1-2, GPA T9 and LPAA T expression in R5 stage and the high expression of GPA T9 and DGA T1-2 in R6 stage.