油葵HaFAD2-5基因的克隆及其对低温和光照的响应

Cloning of HaFAD2-5 Gene in Helianthus annuus L. and Its Response to Low Temperature and Light

油葵(Helianthus annuus L.)是世界重要的油料作物之一,种子中含有大量亚油酸,但其合成与调控机制尚不清楚。本实验利用RT-PCR技术从油葵叶片中克隆了一个FAD2家族基因,命名为HaFAD2-5。并使用半定量RT-PCR分析其在低温和光照处理下的表达模式。结果表明,HaFAD2-5基因的开放阅读框(ORF)为1 113 bp,编码蛋白质含370个氨基酸,等电点(p I)为6.52,相对分子质量为43.21 kD。半定量RT-PCR表明,低温和光照处理可调节HaFAD2-5在油葵根、茎和叶中的表达,但响应程度不同。茎和叶中HaFAD2-5的表达量在低温下增高;暗处理1 d和2 d后,根和叶中HaFAD2-5的表达量下降;暗处理1 d后,茎中HaFAD2-5的表达量达到最高,暗处理2 d后又降低。研究表明,HaFAD2-5可能参与油葵对低温胁迫应答的调节,并且其表达具有昼夜节律性。

Oil sunflower（Helianthus annuus L.） is one of the important oil crops in the world.There are plenty of linoleic acid in its seeds,but the synthesis and regulation mechanism are still unclear.In this study,a FAD2 family gene was cloned from the leaves of oil sunflower by RT-PCR,which was named as HaFAD2-5.The expression pattern of HaFAD2-5 was analyzed by semi-quantitative RT-PCR under low temperature and light treatment.The results showed that the open reading frame（ORF） of HaFAD2-5 gene was 1 113 bp,encoding 370 amino acids.The relative molecular mass of HaFAD2-5 was 43.21 k D with isoelectric point（pI） of 6.52.Semi-quantitative RT-PCR indicated that low temperature and light treatment could regulate the expression of HaFAD2-5 in roots,stems and leaves of Helianthus annuus,but the expression pattern was different.The low temperature stress treatment resulted in the increase of HaFAD2-5 expression in stems and leaves.After 1 day and 2 days of dark treatment,HaFAD2-5 expression in roots and leaves decreased.While in stems,HaFAD2-5 expression achieved the highest after 1 day of dark treatment but decreased after 2 days of dark treatment.Our study suggested that HaFAD2-5 might be involved in the regulation of Helianthus annuus response to cold stress,and its expression might have diurnal rhythmicity.