Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-Saving Fertilizers, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, People's Republic of China.
Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250014, Shandong, People's Republic of China.
Microb Cell Fact. 2019 Sep 3;18(1):148. doi: 10.1186/s12934-019-1196-8.
Colonization of Trichoderma spp. is essential for exerting their beneficial functions on the plant. However, the interactions between Trichoderma spp. and plant roots are still not completely understood. The aim of this study was to investigate how TgSWO affect Trichoderma guizhouense to establish themselves in the plant rhizosphere and promote plant growth. In this study, we deeply analyzed the molecular mechanism by which the functional characterization of the TgSWO by expressing different functional region deletion proteins (FRDP) of TgSWO.
Root scanning analysis results showed that TgSWO could dramatically increase root density and promote growth. In addition, we also found that TgSWO could expand root cell walls, subsequently increase root colonization. Moreover, knockout of TgSWO mutants (KO) or overexpression of TgSWO mutants (OE) produced greatly reduced or increased the number of cucumber root, respectively. To clarify the molecular mechanism of TgSWO in plant-growth-promotion, we analyzed the ability of different FRDP to expand the root cell wall. The root cell wall architecture were considerably altered when treated by ΔCBD protein (the TgSWO gene of lacking in the CBD domain was cloned and heterologously expressed), in correlation with the present YoaJ domain of TgSWO. In contrast, neither the expansion of cell walls nor the increase of roots was detectable in ΔYoaJ protein.
Our results emphasize the YoaJ domain is the most critical functional area of TgSWO during the alteration of cell wall architecture. Simultaneously, the results obtained in this study also indicate that TgSWO might play a plant-growth-promotion role in the Trichoderma-plant interactions by targeting the root cell wall.
木霉属（Trichoderma spp.）的定殖对于发挥其对植物的有益功能至关重要。然而，木霉属与植物根系之间的相互作用仍不完全清楚。本研究旨在探讨 TgSWO 如何影响贵州木霉（Trichoderma guizhouense）在植物根际定殖并促进植物生长。在本研究中，我们通过表达 TgSWO 的不同功能区域缺失蛋白（FRDP），深入分析了 TgSWO 功能特征的分子机制。
根扫描分析结果表明，TgSWO 可显著增加根密度并促进生长。此外，我们还发现 TgSWO 可扩展根细胞壁，随后增加根定殖。此外，TgSWO 缺失突变体（KO）或过表达突变体（OE）的敲除或过表达分别产生了大大减少或增加黄瓜根的数量。为了阐明 TgSWO 在植物促生长中的分子机制，我们分析了不同 FRDP 扩展根细胞壁的能力。当用 ΔCBD 蛋白（缺乏 CBD 结构域的 TgSWO 基因被克隆并异源表达）处理时，根细胞壁结构发生了很大的改变，与 TgSWO 中的 YoaJ 结构域相关。相比之下，ΔYoaJ 蛋白既不能扩展细胞壁，也不能增加根的数量。
我们的结果强调了 YoaJ 结构域是 TgSWO 在细胞壁结构改变过程中最关键的功能区域。同时，本研究的结果还表明，TgSWO 可能通过靶向根细胞壁在木霉-植物相互作用中发挥促植物生长的作用。
