背景:棉花是一种重要的经济作物,也是美洲斑潜蝇的寄主。果胶甲基酯酶(PME)介导的果胶代谢在植物的多个生物学过程中起着不可或缺的作用。然而,PME的多效性功能通常会对作物对害虫的抗性产生不可预测的影响。此外,PME是否以及如何影响美洲斑潜蝇的易感性尚不清楚。
结果:这里,我们分离了位于细胞壁中的GhPME36,从陆地棉(陆地棉L.)。有趣的是,GhPME36在棉花中的过表达导致对美洲斑潜蝇的严重易感性,但增加了拟南芥的叶片生物量。细胞学观察表明,GhPME36-OE棉叶中的细胞壁比WT叶中的脱甲基酯化果胶更薄,而GhPME36-OE棉叶细胞壁的可溶性糖含量相应较高;这两个因素都吸引了美洲斑潜蝇以GhPME36-OE棉叶为食。代谢组学分析表明葡萄糖显著差异积累。转录组学分析进一步显示,当GhPME36过表达时,DEGs富含葡萄糖代谢途径,表明GhPME36通过影响细胞壁生物合成的结构和成分来加剧对美洲斑潜蝇的易感性。此外,GhPME36与另一种果胶修饰酶相互作用,GhC/VIF1,保持了果胶甲酯化的动态稳固性。
结论:综合来看,我们的结果揭示了GhPME36加重对美洲斑潜蝇易感性的细胞学和分子机制。这项研究拓宽了PME功能的知识,并为植物对害虫的抗性和转基因植物的安全性提供了新的见解。
BACKGROUND: Cotton is an important economic crop and a host of Liriomyza sativae. Pectin methylesterase (PME)-mediated pectin metabolism plays an indispensable role in multiple biological processes in planta. However, the pleiotropic functions of PME often lead to unpredictable effects on crop resistance to pests. Additionally, whether and how PME affects susceptibility to Liriomyza sativae remain unclear.
RESULTS: Here, we isolated GhPME36, which is located in the cell wall, from upland
cotton (Gossypium hirsutum L.). Interestingly, the overexpression of GhPME36 in
cotton caused severe susceptibility to Liriomyza sativae but increased leaf biomass in Arabidopsis. Cytological observations revealed that the cell wall was thinner with more demethylesterified pectins in GhPME36-OE cotton leaves than in WT leaves, whereas the soluble sugar content of GhPME36-OE
cotton leaf cell walls was accordingly higher; both factors attracted Liriomyza sativae to feed on GhPME36-OE
cotton leaves. Metabolomic analysis demonstrated that glucose was significantly differentially accumulated. Transcriptomic analysis further revealed DEGs enriched in glucose metabolic pathways when GhPME36 was overexpressed, suggesting that GhPME36 aggravates susceptibility to Liriomyza sativae by affecting both the structure and components of cell wall biosynthesis. Moreover, GhPME36 interacts with another pectin-modifying enzyme, GhC/VIF1, to maintain the dynamic stability of pectin methyl esterification.
CONCLUSIONS: Taken together, our results reveal the cytological and molecular mechanisms by which GhPME36 aggravates susceptibility to Liriomyza sativae. This study broadens the knowledge of PME function and provides new insights into plant resistance to pests and the safety of genetically modified plants.