PxCAD1与Cry1Ac蛋白混合物对小菜蛾 生长发育及体内酶活性的影响
Effects of PxCAD1 and Cry1Ac protein mixture on the growth, development and in vivo enzyme activity of Plutella xylostella
黄秀芳 龚莉君 程周强 廖文宇 文礼章 张友军 杨中侠
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DOI：10.7679/j.issn.2095-1353.2021.113
作者单位：湖南农业大学植物保护学院，长沙 410128；中国农业科学院蔬菜花卉研究所，北京 100081
中文关键词：小菜蛾；Cry1Ac；钙粘蛋白；生长发育；解毒酶；消化酶
英文关键词：Plutella xylostella; Cry1Ac; cadherin; growth and development; detoxification enzymes; digestive enzymes
中文摘要：
【目的】 PxCAD1肽段可显著增强Cry1Ac的杀虫活性，探究其与Cry1Ac混合物对靶标昆虫生物学及体内酶活性的影响对明确其增效机制具有重要意义。【方法】 采用叶片浸渍法，以PxCAD1肽段与Cry1Ac毒素的混合蛋白饲喂小菜蛾Plutella xylostella 3龄幼虫，观察并统计小菜蛾死亡率、化蛹率和羽化率，并测定小菜蛾幼虫体体内羧酸酯酶、谷胱甘肽-S-转移酶、总蛋白酶和类胰蛋白酶的变化趋势。【结果】 与对照相比，处理组幼虫的死亡率显著升高，化蛹率减少，羽化率显著降低；3龄幼虫在取食PxCAD1肽段与Cry1Ac毒素混合蛋白24 h和48 h后，羧酸酯酶活性显著升高，72 h显著降低，谷胱甘肽-S-转移酶活性在24 h显著升高，48 h显著降低，72 h则无显著差异，而总蛋白酶活性仅在72 h显著低于对照，类胰蛋白酶活性在各时间点无显著变化。【结论】 PxCAD1不仅对Cry1Ac具有显著增效作用，同时对小菜蛾幼虫的生长发育及体内羧酸酯酶、谷胱甘肽-S-转移酶及总蛋白酶的活性产生不利影响。该结果将有助于进一步研究中肠受体蛋白对Cry1Ac的增效机制。
英文摘要：
[Objectives] To investigate the
synergistic mechanism responsible for the increased insecticidal activity of
Cry1Ac when combined with the PxCAD1 peptide. [Methods] The leaf dip bioaasay method was used to
treat leaves fed to a randomly selected group of 3rd instar Plutella xylostella larvae
with a mixture of the PxCAD1 peptide and Cry1Ac toxin, after which their
larval mortality, pupation rate and emergence rate were recorded and compared to those of a control
group. In addition, trends in Carboxylesterase,
Glutathione-S-transferase, total protease and trypsin-like activity, were measured and
compared between groups. [Results] The mortality rate and
emergence rate of larvae fed leaves treated with the PxCAD1 peptide and
Cry1Ac toxin mixture were significantly higher than that of the control group,
and their pupation rate was also lower. The carboxylesterase activity of
treatment group larvae was significantly higher than that of the control group
after 24 h and 48 h, then significantly decreased after 72 h. Glutathione-S-transferase
activity was significantly higher after 24 h, then decreased significantly
after 48 h with no further change after 72 h. Total protease activity was
significantly lower than that of the control group only at 72 h, and there was
no significant change in tryptase activity. [Conclusion] PxCAD1 not only has a significant
synergistic effect on Cry1Ac, but also has an adverse effect on the growth and
development of P. xylostella larvae and the activity of
Carboxylesterase, Glutathione-S-transferase and total protease in vivo. These results facilitate further study of the synergistic effects
of midgut receptor proteins on Cry1Ac.