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香味是优良稻米品质的重要衡量标准之一,2-乙酰-1-吡咯啉(2AP)是最主要的香味物质,然而2AP生物合成机理至今仍未确凿。本研究筛选了与2AP生物合成密切相关的甜菜碱脱氢酶2基因(Badh2)在30份水稻材料中的3种突变类型,从中发现1份新的香稻材料渝恢2103,该材料Badh2基因序列编码区无突变,遗传分析显示渝恢2103与badh2-E7突变型香稻宜香1B香味基因不等位,与非香稻杂交F2香与非香分离比接近9∶7,与香稻杂交F2香与非香分离比接近7∶9,表明渝恢2103的香味受多基因控制。进一步利用实时荧光定量PCR技术(qRT-PCR)比较了与2AP生物合成相关基因在日本晴、渝恢2103和宜香1B的表达情况,结果显示,Badh2基因在日本晴和渝恢2103中表达差异不大,但在宜香1B中表达量异常高;多数脯氨酸与谷氨酸代谢途径相关基因在宜香1B中的表达水平显著高于日本晴和渝恢2103;推测宜香1B的2AP合成同时受Badh2基因以及脯氨酸与谷氨酸代谢途径相关基因的影响;渝恢2103香味形成可能与这些基因无必然联系。渝恢2103特殊的遗传特性可能为水稻香味形成机理研究提供新的突破点。
Fragrance is one of the most important criteria for the quality of good rice. 2-Acetyl-1-pyrroline (2AP) is the most important flavor substance, however, the mechanism of 2AP biosynthesis is still not conclusive. This study screened 3 kinds of mutation types of Badh2, which is closely related to 2AP biosynthesis, in 30 rice materials. One new fragrant rice material, Yuhui 2103, was screened from this study. Badh2 gene There was no mutation in the sequence coding region. Genetic analysis showed that Yuhui 2103 and badh2-E7 mutant Xiangxiangxiang 1B scented genes were heterogeneous. The F2 aromatic and non-fragrant hybrids were nearly 9: 7 with non-fragrant rice, F2 fragrant and non-fragrant separation ratio close to 7: 9, indicating that the flavor of Yu Hui 2103 controlled by multiple genes. The expression of 2AP biosynthesis-related genes in Nipponbare, Yuhui 2103 and Yixiang 1B were further compared by real-time quantitative PCR (qRT-PCR). The results showed that there was no significant difference in Badh2 gene expression between Nipponbare and Yuhui 2103 , But the expression level in Yixiang 1B was abnormally high. The expression level of most proline and glutamate metabolic pathways in Yixiang 1B was significantly higher than that of Nipponbare and Yuhui 2103. Badh2 gene and proline and glutamate metabolic pathway related genes; Yu Hui 2103 flavor formation may not necessarily associated with these genes. The special genetic characteristics of Yuhui 2103 may provide a new breakthrough point for the research on the formation mechanism of rice scent.