桉蝙蛾3龄幼虫嗅觉结合蛋白的高表达量与其寄主选择时期的一致性

High expression of binding proteins in 3^(rd) larvae of Endoclita signifier consistent with its host selection behavior

为分析桉蝙蛾Endoclita signifer幼虫嗅觉蛋白中结合蛋白(OBPs+CSPs)在不同龄期和体段的表达,揭示桉蝙蛾幼虫结合蛋白的时空表达谱,基于表达谱阐明其与幼虫寄主选择行为的关系,本研究利用qRT-PCR分析桉蝙蛾幼虫结合蛋白在4个龄期和3个体段中的表达。在各龄期幼虫的头部中,EsigOBP2、EsigOBP5、EsigOBP8、EsigGOBP2、EsigGOBP3、EsigGOBP6、EsigCSP1和EsigCSP2均在3龄幼虫头部显著地高量表达,同时82.4%的结合蛋白在幼龄幼虫(3龄和5龄)的某个体段表达量最高。此外,47.1%和35.3%的结合蛋白在桉蝙蛾幼虫腹部和胸部的表达量最高。以上筛选出的8个结合蛋白是桉蝙蛾3龄幼虫在地栖转树栖过程中,参与寄主识别最主要的蛋白;且结合蛋白在3龄幼虫头部的显著高量表达与3龄幼虫转移栖息地和选择寄主相一致,同时结合蛋白在幼龄幼虫中的高量表达可能与选择寄主后幼龄幼虫对寄主挥发物的适应相一致;本研究支持了桉蝙蛾幼龄幼虫寄主选择的推测。与其他昆虫一致,结合蛋白在桉蝙蛾幼虫的腹部和胸部(非嗅觉部位)高量表达,其功能有待解读。

The expression of binding proteins of olfactory proteins(OBPs+CSPs) in Endoclita signifier larvae at different instar and somite were analyzed to reveal the spatio-temporal expression profiles of binding proteins of E.signifier larvae,and to elucidate the relationship between binding proteins and host selection behavior of larvae based on the expression profiles.The expression of the expression of larval binding proteins in four instar and three somite was analyzed by the real-time fluorescence quantitative PCR(qRT-PCR).In the head of each larval instar,EsigOBP2,EsigOBP5,EsigOBP8,EsigOBP2,EsigOBP3,EsigOBP6,EsigCSP1 and EsigCSP2 were significantly and highly expressed in the heads of 3^(rd) larvae,and 82.4% of the binding proteins were expressed in some somite of 3^(rd) and 5^(th) larvae simultaneously.In addition,47.1% and 35.3% of binding proteins were most expressed in the abdomen and thorax of E.signifier larvae.The eight binding proteins screened above were the most important proteins involved in host recognition of 3^(rd) larvae of E.signifier in the process of terrestrial to arboreal transformation,and the significant high expression of binding protein in the head of 3^(rd) larvae was consistent with its habitat transfer and host selection.Meanwhile,the high expression of binding protein in the young larvae might be consistent with the adaptation of the young larvae to host volatiles after host selection.This study supported the speculation of host selection of young larvae of E.signifier.In line with other insects,binding proteins were highly expressed in the abdomen and thorax(non-olfactory parts) of E.signifier larvae,and their function remains to be interpreted.