椰子脂肪酸积累及与FatB基因表达关系研究

为筛选控制椰子果实中低碳链脂肪酸积累的关键FatB基因,本研究以海南本地高种绿椰四个发育时期的果实为试验材料,参考国家标准GB/T2906-1982谷类、油料作物种子粗脂肪测定方法,用索氏提取法提取果肉脂肪酸,应用气质联用检测技术测定各发育时期脂肪酸含量及组分,同时应用qRT-PCR对椰子脂肪酸合成相关基因FatB1、FatB2及FatB3进行相对定量分析,明确各发育时期椰子果实脂肪酸积累与FatB基因表达量变化之间的关系。结果表明:(1)椰子油含9种脂肪酸成分,在椰子果实发育的早期(第6和第7个月),棕榈酸、硬脂酸和油酸的含量较高,月桂酸和肉豆蔻酸相对含量较低,通过实时荧光定量PCR发现,此时FatB1基因的相对表达量较高。(2)而在椰子果实发育的后期(第8和第9个月),棕榈酸、硬脂酸和油酸的相对含量迅速降低,月桂酸和肉豆蔻酸相对含量迅速升高,FatB2和FatB3基因的相对表达量较高,FatB1的表达量略有降低。该研究初步掌握了椰果各发育时期FatB基因表达量与脂肪酸成分间的变化趋势,该结果为将来筛选控制椰子果实中低碳链脂肪酸积累的关键FatB基因奠定基础,同时为椰子脂肪酸成分的分子改良提供理论依据。

Relationship between fatty acid accumulation and FatB gene expression in Cocos nucifera

In order to screen the key genes controlling the accumulation of low-carbon chain fatty acid in coconut fruit, Hainan high-grade green coconut fruits at four growth stages were used as experimental materials, according to GB/T 2906-1982 method for the determination of crude fats in cereals and oil crop seeds, the oil in fresh fruit of Hainan high-grade green coconut was extracted by Soxhler extractor, the contents and components of fatty acids were determined by GC-MS, and quantitative analyses of FatB1, FatB2 and FatB3 genes were carried out by qRT-PCR. The relationship between fatty acid accumulation and FatB gene expression in coconut fruit at each development stage were clarified. The results were as follows:(1)Coconut oil contains nine kinds of fatty acid. In the early growth stage of coconut fruit development(the 6th and 7th months), the contents of palmitic acid, stearic acid and oleic acid were higher, and the relative contents of lauric acid and myristic acid were lower. The relative expression of FatB1 gene was higher through real-time fluorescent quantitative PCR.(2)In the later growth stage of coconut fruit(the 8th and 9th month), the relative contents of palmitic acid, stearic acid and oleic acid decreased rapidly, the relative contents of lauric acid and myristic acid increased rapidly, the relative expression of FatB2 and FatB3 genes was higher, and the expression of FatB1 was lower. Through this study, we preliminarily explored the change trend of FatB gene expression and fatty acid composition in different growth stages of coconut fruit. The results establish foundation for screening the key FatB gene that controls the accumulation of low-carbon chain fatty acids in coconut fruit, and provide theoretical basis for the molecular improvement of fatty acid composition.