Covering Soybean Leaves With Cellulose Nanofiber Changes Leaf Surface Hydrophobicity and Confers Resistance Against Phakopsora pachyrhizi

Abstract

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.

Breeding for disease resistance in soybean: a global perspective

“…The most recent and novel attempt to control this disease is the treatment of liquid suspension of cellulose nanofibers (CNF) to plants before inoculation with the pathogen. The authors suggest that this application changes the hydrophobicity of the leaf surface, suppressing P. pachyrhizi CHSs (chitin synthases) expression related to chitin formation, which are associated with reduced formation of pre-infection structures (Saito et al 2021 ).…”

Appressoria—Small but Incredibly Powerful Structures in Plant–Pathogen Interactions

“…Phakopsora pachyrhizi is the causative agent of Asian soybean rust, which is the most devastating soybean production disease worldwide. The germ tubes and appressoria formation can be hindered with cellulose nanofibers (CNFs) covering soybean leaves [151].…”

Sustainable Applications of Nanofibers in Agriculture and Water Treatment: A Review

“…Recently, many researchers studied the main applications of nanofibers in agriculture because of their tailoring properties, including the biocompatible and biodegradable features, high surface area and porosity, ease of active ingredient additions (i.e., fungicides, insecticides, herbicides, pesticides, hormones, and pheromones), and flexibility of electrospun nanofibers [55]. Nanofibers can apply for plant protection (through applying pesticides for pest control), plant growth (through applying hormones and/or fertilizers), pollution and contamination controls, and irrigation systems (through water filtration), as reported in Table 3 by Meraz-Dávila et al [56], Raja et al [57], and [58]. The main applications of nanofibers in the agricultural field may include coating seeds [60][61][62], nanofibers-based filters for irrigation systems [65], nanofibers for plant protection [56] through encapsulation of fungicides [66,67], or detecting trace some pesticides in water [69], nano-silica grafted fiber [70], smart nanotextiles for sustainable agriculture [13], nanofibers for encapsulation of agrochemicals including fertilizer [75], and phytohormones [71,72].…”

“…The synthetic material-based composites should be replaced by natural ones in several manufacturing industries, such as the field of textiles, which flax was used in ancient Egypt nearly 7000 years ago [3]. The cellulose is the most important component of the lignocellulosic natural fibers, which many plants could order their content of cellulose (%) as follows straw of rice (41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57), leaf of date palm (46), leaf of abaca (56)(57)(58)(59)(60)(61)(62)(63), bast of jute (61)(62)(63)(64)(65)(66)(67)(68)(69)(70)(71), leaf of banana , leaf of sisal (65), bast of hemp (68), bast of ramie (68.6-76.2), bast of flax (71), bast of kenaf (72), leaf of curaua (73.6), leaf of pineapple (81), bast of nettle (81)…”