PDF(Pubmed)
Abstract：
Many plant species, particularly legumes, protect themselves with saponins. Previously, a correlation was observed between levels of oleanolic acid-derived saponins, such as hederagenin-derived compounds, in the legume Medicago truncatula and caterpillar deterrence. Using concentrations that reflect the foliar levels of hederagenin-type saponins, the sapogenin hederagenin was not toxic to 4th instar caterpillars of the cabbage looper Trichoplusia ni nor did it act as a feeding deterrent. Female caterpillars consumed more diet than males, presumably to obtain the additional nutrients required for oogenesis, and are, thus, exposed to higher hederagenin levels. When fed the hederagenin diet, male caterpillars expressed genes encoding trypsin-like proteins (LOC113500509, LOC113501951, LOC113501953, LOC113501966, LOC113501965, LOC113499659, LOC113501950, LOC113501948, LOC113501957, LOC113501962, LOC113497819, LOC113501946, LOC113503910) as well as stress-responsive (LOC113503484, LOC113505107) proteins and cytochrome P450 6B2-like (LOC113493761) at higher levels than females. In comparison, female caterpillars expressed higher levels of cytochrome P450 6B7-like (LOC113492289). Bioinformatic tools predict that cytochrome P450s could catalyze the oxygenation of hederagenin which would increase the hydrophilicity of the compound. Expression of a Major Facilitator Subfamily (MFS) transporter (LOC113492899) showed a hederagenin dose-dependent increase in gene expression suggesting that this transporter may be involved in sapogenin efflux. These sex-related differences in feeding and detoxification should be taken into consideration in insecticide evaluations to minimize pesticide resistance.
摘要：
许多植物物种,尤其是豆类,用皂甙保护自己。以前,齐墩果酸衍生的皂苷水平之间存在相关性，如hederagenin衍生的化合物，在豆科植物紫花苜蓿和毛毛虫威慑中。使用反映hederagenin型皂苷叶面水平的浓度，saposeninhederagenin对卷心菜弯子Trichopulsiani的4龄毛毛虫没有毒性，也没有起到喂养威慑作用。雌性毛虫比雄性消耗更多的饮食，大概是为了获得卵子发生所需的额外营养，而且是，因此，暴露于较高的hederagenin水平。当喂海德拉胶素饮食时，雄性毛虫表达的基因编码胰蛋白酶样蛋白（LOC113500509，LOC113501951，LOC113501953，LOC113501966，LOC113501965，LOC113499659，LOC113501950，LOC113501948，LOC113501957，LOC113501962，LOC1134919，LOC113501946，LOC113503910）以及响应水平高于L0135相比之下,雌性毛虫表达较高水平的细胞色素P4506B7样(LOC113492289)。生物信息学工具预测，细胞色素P450可以催化hederagenin的氧合，这将增加化合物的亲水性。主要促进子家族（MFS）转运蛋白（LOC113492899）的表达显示基因表达中hederagenin的剂量依赖性增加，表明该转运蛋白可能参与皂苷元外排。在杀虫剂评估中应考虑这些与性别有关的进食和解毒差异，以最大程度地减少对杀虫剂的抗药性。
