Hormonal and proteomic analyses of southern blight disease caused by Athelia rolfsii and root chitosan priming on Cannabis sativa in an in vitro hydroponic system

Abstract

Southern blight disease, caused by the fungal pathogen Athelia rolfsii, suppresses plant growth and reduces product yield in Cannabis sativa agriculture. Mechanisms of pathology of this soil‐borne disease remain poorly understood, with disease management strategies reliant upon broad‐spectrum antifungal use. Exposure to chitosan, a natural elicitor, has been proposed as an alternative method to control diverse fungal diseases in an eco‐friendly manner. In this study, C. sativa plants were grown in the Root‐TRAPR system, a transparent hydroponic growth device, where plant roots were primed with .2% colloidal chitosan prior to A. rolfsii inoculation. Both chitosan‐primed and unprimed inoculated plants displayed classical symptoms of wilting and yellowish leaves, indicating successful infection. Non‐primed infected plants showed increased shoot defense responses with doubling of peroxidase and chitinase activities. The levels of growth and defense hormones including auxin, cytokinin, and jasmonic acid were increased 2–5‐fold. In chitosan‐primed infected plants, shoot peroxidase activity and phytohormone levels were decreased 1.5–4‐fold relative to the unprimed infected plants. When compared with shoots, roots were less impacted by A. rolfsii infection, but the pathogen secreted cell wall‐degrading enzymes into the root‐growth solution. Chitosan priming inhibited root growth, with root lengths of chitosan‐primed plants approximately 65% shorter than the control, but activated root defense responses, with root peroxidase activity increased 2.7‐fold along with increased secretion of defense proteins. The results suggest that chitosan could be an alternative platform to manage southern blight disease in C. sativa cultivation; however, further optimization is required to maximize effectiveness of chitosan.

Impact of Chitosan-Based Foliar Application on the Phytochemical Content and the Antioxidant Activity in Hemp (Cannabis sativa L.) Inflorescences

“…This is the first evidence of the ability of CHT-based treatments to induce the accumulation of secondary metabolites in hemp inflorescences. In fact, the only other study related to the treatment of hemp plants with CHT concerned the ability of this elicitor to enhance defense responses in hemp roots through the up-regulation of defense-related genes and the secretion of defense proteins in the root exudate [43]. Conversely, the ability of CHT-based applications to increase the levels of phenolic compounds has been reported in many other plant species, including many herb plants.…”

Chitosan induces salicylic acid local and systemically in banana plants and reduces colonization by the pathogenFusarium oxysporumf. sp. cubense TR4

“…Chitosan also modifies root cell membranes architecture and root differentiation 12,36 . Plasma membrane of plant cells regulates nutrient exchanges and controls signal perception, inducing adaptive responses to environmental changes 37 .…”