ABSTRACT Identifying the maximum level of inherent defense against harmful insects in natural variation among wild lineages of crop plants may result in high yield tolerant varieties and reducing use of chemical insecticides. However, knowledge of natural cotton genotypes with high insect‐resistance is still indistinguishable at the biochemical or molecular level. In the present study, different cultivated Gossypium hirsutum varieties were evaluated for their inherent insect-tolerance against two major cottons chewing pests. The insect bio-assay identified two tolerant and one susceptible cotton varieties. The study demonstrates difference in phenolic acids, proanthocyanidin and tannin accumulation in tolerant and susceptible varieties. The post–infestation of chewing pests increases transcript level of the phenylpropanoid pathway genes were detected in tolerant varieties as compared to the susceptible varieties. Altogether, chewing pest-tolerance level in cotton varieties is the cumulative effect of enhanced phenylpropanoid pathway genes expression and secondary metabolite leading to defense responses to conventional host plant.

中文翻译：

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不同棉花品种酚类和苯丙烷途径基因对咀嚼害虫的不同防御活性

摘要 在农作物野生谱系的自然变异中确定对有害昆虫的最大固有防御水平可能会导致高产耐受品种并减少化学杀虫剂的使用。然而，关于具有高抗虫性的天然棉花基因型的知识在生化或分子水平上仍然难以区分。在本研究中，评估了不同栽培的陆地棉品种对两种主要棉花咀嚼害虫的固有昆虫耐受性。昆虫生物测定鉴定了两种耐受性和一种易感性棉花品种。该研究表明，耐受和易感品种的酚酸、原花青素和单宁的积累存在差异。与易感品种相比，咀嚼害虫的侵染后增加了在耐受品种中检测到的苯丙烷途径基因的转录水平。总之，棉花品种的咀嚼害虫耐受水平是苯丙烷途径基因表达增强和次生代谢物导致对常规宿主植物的防御反应的累积效应。