美国白蛾丝素蛋白基因的鉴定、时空表达及取食不同寄主植物后的表达响应

Cloning and spatio-temporal expression of fibroinsand its expression in response to feeding on different host in Hyphantria cunea(Lepidoptera:Arctiidae)

美国白蛾Hyphantria cunea Drury被列为我国林业检疫性害虫,其l~4龄幼虫具有吐丝结网幕的习性。为探究丝素蛋白基因的表达特性,本研究利用PCR技术克隆了美国白蛾的HcP25(Genbank登录号:OL625670)、HcFib-H(Genbank登录号:OL625672)、HcFib-L(Genbank登录号:OL625671)3条丝素蛋白基因,并进行生物信息学分析;利用RT-qPCR技术检测美国白蛾3条丝素蛋白基因的表达特性。结果表明:3条丝素蛋白基因序列比对均与车前灯蛾Arctia plantaginis丝素蛋白一致性最高,系统进化分析显示丝素蛋白HcP25、HcFib-H、HcFib-L在鳞翅目不同科之间在出现较大的分化。RT-qPCR试验结果显示HcP25、HcFib-H、HcFib-L 3基因相对表达量与网幕产生高峰期(1龄、2龄)相一致。3种丝素蛋白均在丝腺中特异性高水平表达,在头部及脂肪体中有少量表达。美国白蛾幼虫取食不同寄主植物后,3种丝素蛋白基因呈现不同的表达规律;取食杨树Populus L.处理组中HcP25与HcFib-H基因相对表达量极显著高于取食其它寄主处理,而取食山樱花Cerasus serrulata var.lannesiana和日本晚樱Cerasus serrulata处理组中HcFib-L基因表达量最高。研究结果为进一步探究丝素蛋白介导的美国白蛾对不同寄主的适应机制及其扩散机制奠定基础,也为开发美国白蛾防治新方法提供了潜在的基因靶标。

Hyphantria cunea Drury is listed as quarantine pests in China,and its 1^(st)~4^(th) larva aggregate by creating silk webs on tree branches,where the larvae feed and live as they growing.To explore the expression characteristics of silk fibroin genes.In this study,three silk fibroin genes were cloned from H.cunea by PCR and the results of sequence alignment showed that the silk fibroin genes of H.cunea had the highest consistency with those of Arctia plantaginis.Phylogenetic analysis showed that HcP25,HcFib-H and HcFib-L differentiated greatly among different families of Lepidoptera.RT-qPCR results indicated that the expression of HcP25,HcFib-H and HcFib-L in different developmental stages showed dynamic change and the expression level of HcP25,HcFib-H and HcFib-L was significantly related to the stage of silk-producing(1^(st) and 2^(nd) instars).RT-qPCR results in different tissues showed that HcP25,HcFib-H and HcFib-L were mainly expressed in silk glands and a small amount in head and fat body.Moreover,after feeding on different hosts,the expression trends of HcP25,HcFib-H and HcFib-L were different and the relative expression of HcP25 and HcFib-H genes of H.cunea larvae fed on Populus L.was significantly higher than that of other host populations,while the relative expression of HcFib-L fed on Cerasus serrulata var.lannesiana and Cerasus serrulata was significantly higher than that of other hosts.The results of this study laid a foundation for in-depth study of web-mediated adaptation and diffusion mechanism of H.cunea to different hosts,and provided potential genetic targets for the development of new control methods of H.cunea.