Zhengzhou Research Base, National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, China.
Hainan Seed Industry Laboratory, Sanya, 572000, China.
BMC Biol. 2024 Sep 11;22(1):197. doi: 10.1186/s12915-024-01999-7.
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.
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.
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.
棉花是一种重要的经济作物，也是南美斑潜蝇的宿主。果胶甲酯酶（PME）介导的果胶代谢在植物体内的多个生物学过程中起着不可或缺的作用。然而，PME 的多效性功能常常导致对作物抗虫性的不可预测影响。此外，PME 是否以及如何影响对南美斑潜蝇的易感性尚不清楚。
我们从陆地棉（Gossypium hirsutum L.）中分离出位于细胞壁中的 GhPME36。有趣的是，棉花中 GhPME36 的过表达导致对南美斑潜蝇的敏感性严重增加，但增加了拟南芥的叶片生物量。细胞学观察表明，GhPME36-OE 棉花叶片的细胞壁更薄，具有更多去甲酯化的果胶，而 GhPME36-OE 棉花叶片细胞壁的可溶性糖含量相应更高；这两个因素都吸引了南美斑潜蝇来取食 GhPME36-OE 棉花叶片。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表明，GhPME36 过表达时，富集了参与葡萄糖代谢途径的 DEGs，表明 GhPME36 通过影响细胞壁生物合成的结构和组成来加剧对南美斑潜蝇的易感性。此外，GhPME36 与另一种果胶修饰酶 GhC/VIF1 相互作用，以维持果胶甲酯化的动态稳定性。
综上所述，我们的结果揭示了 GhPME36 加剧对南美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，并为植物抗虫性和转基因植物的安全性提供了新的见解。
