丙酮酸羧化酶在棉蚜生长发育及蜜露形成中的作用

Role of pyruvate carboxylase in the growth, development and honeydew formation of the cotton aphid Aphis gossypii

中文关键词:棉蚜  丙酮酸羧化酶  蜜露  总糖  生长发育  生命表参数

keywords:Aphis gossypii  pyruvate carboxylase  honeydew  total sugar  growth and development  life table parameter

中文摘要:为探究棉蚜Aphis gossypii丙酮酸羧化酶（pyruvate carboxylase,PYC）基因AgPYC在棉蚜生长发育及蜜露形成中的作用，对棉蚜AgPYC基因进行生物信息学分析，体外合成干扰片段dsAgPYC，通过干扰试验测定沉默AgPYC基因对棉蚜体内及其蜜露中总糖含量、生长发育及种群生命表参数的影响。结果显示：棉蚜AgPYC基因序列具有PYC的典型结构特征，PYC蛋白主要位于线粒体内。棉蚜AgPYC蛋白的氨基酸序列与雪松长足大蚜Cinara cedri体内PYC蛋白的氨基酸序列的亲缘关系最近。在3个dsAgPYC浓度中，浓度750 ng/μL dsAgPYC的沉默效果最好。喷洒750 ng/μL dsAgPYC后72 h，棉蚜体内AgPYC基因的相对表达量较喷洒ds GFP降低了44.5%，棉蚜体内及其蜜露中总糖含量分别较喷洒ddH₂O降低了16.2%和18.1%。喷洒750 ng/μL dsAgPYC后棉蚜体型明显小于其他两个处理，第9天的累计死亡率达47.8%，种群适合度下降至0.71。表明AgPYC基因可能在棉蚜糖代谢、蜜露形成及生长发育过程中起着调控作用。

Abstract:To investigate the role of the pyruvate carboxylase(PYC) gene AgPYC in the growth, development and honeydew production of the cotton aphid Aphis gossypii, bioinformatics analysis of the AgPYC gene was performed. The interference fragment dsAgPYC was synthesized in vitro, and RNA interference assays were conducted to evaluate the effects of AgPYC silencing on the total sugar content in cotton aphids and their honeydews, as well as on aphid growth, developmental and population life table parameters. The results showed that the AgPYC gene sequence possessed typical structural features of PYC, and the predicted PYC protein was primarily localized in mitochondria. Phylogenetic analysis revealed that the amino acid sequence of the AgPYC protein was most closely related to that of PYC protein Cinara cedri. Among the three tested dsAgPYC concentrations, 750 ng/μL dsAgPYC exhibited the highest silencing efficiency. At 72 h after spraying with 750 ng/μL dsAgPYC, the relative expression level AgPYC in cotton aphids decreased by 44.5% compared with that after ds GFP treatment, and the total sugar contents in cotton aphids and their honeydews decreased by 16.2% and 18.1%, respectively, compared with those after ddH₂O treatment. After spraying with 750 ng/μL dsAgPYC, the body size of cotton aphids was markedly smaller than that in the other treatments, the cumulative mortality reached 47.8% on day 9, accompanied by a notable decline in the population fitness index(0.71). These findings indicate that the AgPYC gene may play an important regulatory role in sugar metabolism, honeydew formation, and growth and development in cotton aphids.