枯水椪柑果肉挥发性物质及萜烯类合成途径基因表达特征

摘要

Both GC-MS and RNA-Seq were employed to investigate the changes in volatile compounds and expression pattern of genes involved in biosynthesis pathway of terpenoid in the pulp of Ponkan fruit during section-drying process.The results were as follows:① 13 volatile components were identified from pulp of Ponkan fruit,among which seven components were terpenoid,accounting for more than 85％ of the total volatile contents.② The volatile constituents in pup were same between normal and disordered fruits.In fruits affected by section-drying,the content of total volatiles and terpenoid decreased to 32％ and 22％,respectively,of normal fruits.A total of five volatiles including β-myrcene,d-limonene,γ-terpinene,valencene and dodecanal showed a significant decrease in content during the section-drying process.③ Eight differentially expressed genes involved in terpenoid biosynthesis pathway were identified,all of which were decreased in disordered fruits.The present study elucida ted that the volatile constituents in pulp of Ponkan fruits decreased upon section-drying,which was quite closely related to the decreasing expression of genes involved in terpenoid synthesis.Moreover,this study provided invaluable information for further research to reveal the molecular mechanism underlying section-drying in citrus fruits.%运用GC-MS和RNA-Seq技术研究椪柑果实在发生枯水时,果肉挥发性物质组分及含量和萜烯类化合物合成途径相关基因表达的变化特征.研究结果发现:①椪柑果肉挥发性组分共13种,其中萜烯类物质7种,相对含量超过85％;②椪柑桔水时,果肉挥发性物质含量降为正常果实的32％,其中萜烯类物质下降为正常果实的22％,另外挥发性物质的组分种类不变,有5种挥发性物质的含量发生显著改变,分别是β-月桂烯、d-柠檬烯、γ-松油烯、瓦伦西亚烯和十二醛;③鉴定到8个萜烯类化合物合成途径的差异表达基因,在枯水时全部下调.研究表明椪柑枯水时果肉挥发性物质的含量显著下调,与萜烯类合成途径相关基因表达降低密切相关,为进一步深入研究椪柑枯水发生的分子机制提供依据.