Chitin Nanofiber Elucidates the Elicitor Activity of Polymeric Chitin in Plants

Abstract

Chitin, an N-acetyl-D-glucosamine polymer, is a component of fungal cell walls and a microbe/pathogen-associated molecular pattern that elicits plant defense responses. As polymeric chitin is difficult to handle due to its insolubility in water, many studies on chitin-induced immune responses have used water-soluble low-molecular weight chitin instead. Thus, it is unclear if polymeric chitin can induce resistance. Here, we examined the elicitor activity of chitin nanofiber (CNF) of submicron thickness prepared from polymeric chitin. CNF showed a high dispersing ability in water and induced both reactive oxygen species (ROS) production and chitin-induced defense-related gene expression in Arabidopsis thaliana seedlings. The Arabidopsis chitin elicitor receptor kinase 1 (Atcerk1) mutant, which is impaired in chitin perception, also failed to respond to CNF. CNF exposure triggered ROS generation in suspension-cultured cells from Oryza sativa. Furthermore, pre-treatment of Arabidopsis leaves with CNF effectively reduced pathogen infection by both the fungus Alternaria brassicicola and the bacterium Pseudomonas syringae pv. tomato DC3000. These results demonstrate that CNF has elicitor activity and will help define the role of polymeric chitin in plant immune responses.

Potential Biostimulant Effect of Clam Shells on Growth Promotion of Plantain PIF Seedlings (<i>var</i>. Big Ebanga & Batard) and Relation to Black Sigatoka Disease Susceptibility

“…Such effects of shells or chitin-source treatments on growth promotion and/or host resistance have also been reported for other pathosystems such as cocoa/snail shells/Phytophthora megakarya [9], tobacco/nanochitin/Fusarium spp. [21], chilli/chitosan/Colletotrichum capsica [22], millet/chitosan derivatives/Pyricola grisea [23], tomato/crab shells/Fusarium oxysporum [24] and cocoa/oyster shells/P. megakarya [20] through the possible triggering of biochemical pathways associated with growth promotion and disease resistance [8] [25] [26].…”

Method for Zero-Waste Circular Economy using worms for plastic agriculture: Augmenting polystyrene consumption and plant growth

“…Worms such as superworms (Zophobas morio) and mealworms (Tenebro molitor) belongs to the darkling beetle (Tenebrionidae) family and are naturally voracious pests in agriculture, consuming dry grain stock even though they are food sources themselves in many societies 7 . Mealworms have been recently shown to be able to consume and metabolize plastics 8 safely, a capability attributed to commensal gut bacteria in these worms confirmed with 13 Ccarbon isotope tracing experiments 9 . At the worm stage, they can be kept at high density, and excrete nitrogen-rich waste in the form of frass 10 that can be potential fertilizers for plant crops.…”

“…The worms are also rich in chitin 11,12 , a chemical shown to improve the growth and the yields of plants [13][14][15] . More recently, superworms are also been reported to consume PS, and at a higher rate than mealworms 16 , showing promise in the use of superworms in the fight against plastics.…”

Recent Applications of Chitin- and Chitosan-Based Polymers in Plants

“…CH nanofibers (CNF) can be more feasibly used since they behave as a water-soluble material. Thus, they were tested for their elicitor capacity, and Egusa et al first showed that CNF enhanced resistance against pathogens in A. thaliana and rice [6]. More recently, when challenged with the fungal pathogens, cabbage and strawberry plants, grown in a mixture of soil and CNF, showed a reduction in the number of spots caused by Alternaria brassicicola and lesion size by Colletotrichum fructicola in respect to control plants [7].…”