向日葵Ha KASI基因的生物信息学和表达分析

Bioinformatics and Expression Analysis of HaKASI Gene in Sunflower

KASI编码β-酮脂酰-ACP合酶I,主要催化C4-ACP生成C16-ACP。为了解向日葵HaKASI基因的表达特性及功能,本研究对其编码蛋白进行生物信息学和基因表达模式分析,预测HaKASI为酸性且为亲水性蛋白;结果显示二级结构主要是无规则卷曲,预测亚细胞定位于叶绿体。系统进化分析发现,HaKASI与拟南芥及其他物种的KASI聚在一个大分支上,与莴苣(Lactuca sativa L.) KASI进化关系最近,序列相似性高达92%。HaKASI表达分析结果表明,HaKASI在向日葵种子中表达最高,其次为管状花和茎,在叶、舌状花和根中不表达,HaKASI在高、低油酸种子发育不同时期表达趋势大体一致,表达量均从7~12 DAF升高,之后降低,但在37 DAF,HaKASI在低油酸种子中表达量极高,明显高于高油酸种子,这暗示HaKASI在油酸含量不同的向日葵种子发育后期可能存在不同的表达调控机制。本研究为HaKASI基因功能的研究提供科学依据。

KASI encodes beta-ketoacyl-acyl carrier protein(ACP) synthase I,which mainly plays a catalytic role in the reaction of C4-ACP to C16-ACP.In order to understand the expression characteristics and function of HaKASI gene in sunflower,the bioinformatics of the protein encoded by HaKASI and gene expression pattern were analyzed.It was predicted that Ha KASI was acidic and hydrophilic.The secondary structure of the protein encoded by HaKASI was mainly random coil,and the subcellular localization was predicted in the chloroplast.Phylogenetic analysis showed that HaKASI clustered with KASI of Arabidopsis thaliana and other species in a large branch,and was closely related to Lactuca sativa L.KASI,and the sequence similarity was as high as 92%.The results of expression analysis of HaKASI showed that the expression level of HaKASI was highest in sunflower seeds,followed by tubular flowers and stems,but not in leaves,ligulate flowers and roots.The expression trend of HaKASI in high and low oleic acid seeds at different stages of development was basically the same,and the expression level increased from 7 to 12 DAF and then decreased.But at 37 DAF,the expression level of HaKASI in low oleic acid seeds was extremely high,which was significantly higher than that in high oleic acid seeds.It suggests that HaKASI may have different expression regulation mechanisms at the late development stage of sunflower seeds with different oleic acid content.This study provides a scientific basis for the study of the function of HaKASI gene.