Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Institute of Applied Chemistry, Guizhou University, Guiyang 550025, China.
Engineering and Technology Research Center of Kiwifruit, Guizhou University, Guiyang 550025, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2024 Dec 5;322:124837. doi: 10.1016/j.saa.2024.124837. Epub 2024 Jul 22.
To further reveal the interaction mechanism between plants and pathogens, this study used confocal Raman microscopy spectroscopy (CRM) combined with chemometrics to visualize the biopolymers distribution of kiwifruit cell walls at different infection stages at the cellular micro level. Simultaneously, the changes in the content of various monosaccharides in fruit were studied at the molecular level using high-performance liquid chromatography (HPLC). There were significant differences in the composition of various nutrient components in the cell wall structure of kiwifruit at different infection times after infection by Botryosphaeria dothidea. PCA could cluster samples with infection time of 0-9 d into different infection stages, and SVM was used to predict the PCA classification results, the accuracy >96 %. Multivariate curve resolution-alternating least squares (MCR-ALS) helped to identify single substance spectra and concentration signals from mixed spectral signals. The pure substance chemical imaging maps of low methylated pectin (LMP), high methylated pectin (HMP), cellulose, hemicellulose, and lignin were obtained by analyzing the resolved concentration data. The imaging results showed that the lignin content in the kiwifruit cell wall increased significantly to resist pathogens infection after the infection of B. dothidea. With the development of infection, B. dothidea decomposed various substances in the host cell walls, allowing them to penetrate the interior of fruit cells. This caused significant changes in the form, structure, and distribution of various chemicals on the fruit cell walls in time and space. HPLC showed that glucose was the main carbon source and energy substance obtained by pathogens from kiwifruit during infection. The contents of galactose and arabinose, which maintained the structure and function of the fruit cell walls, decreased significantly and the cell wall structure was destroyed in the late stage of pathogens infection. This study provided a new perspective on the cellular structure changes caused by pathogenic infection of fruit and the defense response process of fruit and provided effective references for further research on the mechanisms of host-pathogen interactions in fruit infected by pathogens.
为了进一步揭示植物与病原菌之间的相互作用机制，本研究采用共聚焦拉曼显微镜光谱（CRM）结合化学计量学方法，在细胞微观水平上可视化猕猴桃细胞壁在不同感染阶段的生物聚合物分布。同时，采用高效液相色谱（HPLC）法从分子水平研究了果实中各种单糖的含量变化。在博落回葡萄座腔菌感染猕猴桃后不同感染时间，猕猴桃细胞壁结构中各种营养成分的组成存在显著差异。PCA 可以将感染时间为 0-9d 的样品聚类到不同的感染阶段，SVM 用于预测 PCA 分类结果，准确率>96%。多变量曲线分辨-交替最小二乘法（MCR-ALS）有助于从混合光谱信号中识别单物质光谱和浓度信号。通过分析解析浓度数据，获得了低甲基化果胶（LMP）、高甲基化果胶（HMP）、纤维素、半纤维素和木质素的纯物质化学成像图谱。成像结果表明，在博落回葡萄座腔菌感染后，猕猴桃细胞壁中的木质素含量显著增加，以抵抗病原菌的感染。随着感染的发展，病原菌分解了宿主细胞壁中的各种物质，使其能够穿透果实细胞内部。这导致了果实细胞壁上各种化学物质的形态、结构和分布在时间和空间上发生了显著变化。HPLC 表明，在感染过程中，病原菌从猕猴桃中获得的主要碳源和能量物质是葡萄糖。维持果实细胞壁结构和功能的半乳糖和阿拉伯糖含量显著下降，病原菌感染后期细胞壁结构被破坏。本研究为病原菌感染果实引起的细胞结构变化和果实的防御反应过程提供了新的视角，并为进一步研究病原菌感染果实中宿主-病原菌相互作用的机制提供了有效参考。
