油葵HaDGAT2基因的功能及表达特性分析

Analysis of Functional and Expression Characteristics of HaDGAT2 Gene in Helianthus annuus L.

二酰甘油酰基转移酶(DGAT)在植物油脂合成中起关键作用,其活性高低与植物含油量显著相关。为探明油葵二酰甘油酰基转移酶2基因(HaDGAT2)的功能,本研究以‘新葵杂5号’为试验材料,从油葵中扩增HaDGAT2基因序列并构建酵母穿梭表达载体pYES2-Ha DGAT2,将重组载体转入酿酒酵母INVSc1后提取酵母总脂肪酸,甲酯化后GC-MS分析。结果显示,在酿酒酵母中可成功诱导HaDGAT2基因,且转HaDGAT2基因酵母中棕榈油酸(16:1)和油酸(18:1)含量与对照相比得到提高。结果表明,HaDGAT2基因在调控油脂合成的过程中具有重要作用。实时荧光定量PCR分析结果表明HaDGAT2基因在油葵根、茎、叶、花、子叶和不同发育时期的种子中都有表达,且在开花后31天的种子中表达量高,说明该基因表达无组织特异性,在油葵种子油脂积累后期起关键调控作用。本研究为深入了解油葵油脂和调控机制提供了基础,为今后利用分子育种手段提高并改良葵花籽油的品质提供了理论基础。

Diacylglycerol acyltransferase(DGAT) plays a key role in the synthesis of vegetable oils, and its activity is significantly related to the oil content of plants. To investigate the function of HaDGAT2 gene in oil sunflower,the CDS of the gene was isolated from oil sunflower ’Xinza5’. Then the recombinant expression vector pYES2 –HaDGAT2 was constructed and transferred into Saccharomyces cerevisiae INVSc1. The total fatty acids of recombinant yeast were analyzed by GC-MS after methylation. The results showed that the palmitoleic acid(16:1) and oleic acid(18:1) were increased in transgenic yeast compared with control, which indicated that HaDGAT2 gene plays an important role in the regulation of lipid synthesis. Quantitative real-time PCR(qRT-PCR) analysis showed that HaDGAT2 gene expressed in root, stem, leaf, flower, cotyledon and seed in different developmental stages, especially expressed the highest in the period of seeds at 31 day after flowering, indicating that the HaDGAT2 gene had no expression specificity and may play an important role in regulating seed oil accumulation during the later stage of seed development. This study laid the foundation for further exploring the molecular mechanism of fatty acids and triacylglycerol in oil sunflower, and provide the theoretical basis for improving the quality of sunflower oil.