Characterization of fatty acid conversion enzymes of soybean and their application for improvement of soybean oil quality

本研究利用X射线辐照大豆后代，通过遗传学和分子生物学方法对大豆脂肪酸合成途径的突变体进行分析，确定了与脂肪酸合成途径相关的基因家族。结果表明，sop_1和sop_2基因控制高棕榈酸性状，st_1和st_2基因控制高硬脂酸性状，ol基因控制高油酸性状，fan和fanx基因控制低亚麻酸性状。来自大豆种子cDNA文库的微粒体ω-6脂肪酸去饱和酶和微粒体ω-3脂肪酸去饱和酶。进一步分析了这些基因在植物激素处理下的表达情况，发现细胞质和微粒体ω-6去饱和酶基因的mRNA积累量协同下降，而ω-3去饱和酶基因的mRNA积累量协同增加。

Previously, we have reported to establish many fatty acid-mutants from X-ray irradiated soybean progenies.In this research, we analyzed their mutants using genetical and molecular biological approach, and then identified the gene family that is involved in fatty acid synthesis pathway. These results lead to conclusion that sop] and sop2 genes control the high palmitic acid character, st1 and st2 genes control the high stearic acid character, ol gene controls high oleic acid character, and fan and fanx genes control low linolenic acid character, respectively.We could isolate some cDNA clones encoding stearoyl-ACP desaturase, microsomal omega-6 fatty acid desaturase and microsomal omega-3 fatty acid desaturase from soybean seed cDNA library. Three of them were identified as corresponding clones to stl, ol and fan genes, respectively.Furthermore, we analyzed the expression of these genes under phytohormone treatments, and found that mRNA accumulations of both plastidal and microsomal omega-6 desaturase genes coordinately decreased, in contrast, that of omega-3 desaturase genes coordinately increased.