Table_1_Covering Soybean Leaves With Cellulose Nanofiber Changes Leaf Surface Hydrophobicity and Confers Resistance Against Phakopsora pachyrhizi.XLSX

Asian soybean rust (ASR) caused by Phakopsora pachyrhizi, an obligate biotrophic fungal pathogen, is the most devastating soybean production disease worldwide. Currently, timely fungicide application is the only means to control ASR in the field. We investigated cellulose nanofiber (CNF) application on ASR disease management. CNF-treated leaves showed reduced lesion number after P. pachyrhizi inoculation compared to control leaves, indicating that covering soybean leaves with CNF confers P. pachyrhizi resistance. We also demonstrated that formation of P. pachyrhizi appressoria, and also gene expression related to these formations, such as chitin synthases (CHSs), were significantly suppressed in CNF-treated soybean leaves compared to control leaves. Moreover, contact angle measurement revealed that CNF converts soybean leaf surface properties from hydrophobic to hydrophilic. These results suggest that CNF can change soybean leaf surface hydrophobicity, conferring resistance against P. pachyrhizi, based on the reduced expression of CHSs, as well as reduced formation of pre-infection structures. This is the first study to investigate CNF application to control field disease.

由专性活体营养型真菌病原菌豆薯层锈菌（Phakopsora pachyrhizi）引发的亚洲大豆锈病（Asian soybean rust, ASR）是全球范围内危害最严重的大豆生产病害。目前，田间防控ASR的唯一手段为及时喷施杀菌剂。本研究探究了纤维素纳米纤维（cellulose nanofiber, CNF）在ASR病害防控中的应用效果。结果显示，相较于对照组叶片，经CNF处理的大豆叶片在接种豆薯层锈菌后病斑数量显著减少，表明通过CNF覆盖大豆叶片可赋予其对豆薯层锈菌的抗性。本研究还证实，相较于对照组，经CNF处理的大豆叶片中，豆薯层锈菌附着胞的形成以及与之相关的基因表达（如几丁质合酶（chitin synthases, CHSs））均受到显著抑制。此外，接触角测量结果表明，CNF可将大豆叶片表面特性从疏水状态转变为亲水状态。综上，本研究结果提示，CNF可通过改变大豆叶片表面疏水性，下调几丁质合酶的表达并抑制侵染前结构的形成，从而赋予大豆对豆薯层锈菌的抗性。本研究是首个探究CNF应用于田间病害防控的相关研究。