β-Glucan and its nanocomposites in sustainable agriculture and environment: an overview of mechanisms and applications

beta-Glucan is an eco-friendly, biodegradable, and economical biopolymer with important roles for acquiring adaptations to mitigate climate change in crop plants. beta-Glucan plays a crucial role in the activation of functional plant innate immune system by triggering the downward signaling cascade/s, resulting in the accumulation of different pathogenesis-related proteins (PR-proteins), reactive oxygen species (ROS), antioxidant defense enzymes, Ca2+-influx as well as activation of mitogen-activated protein kinase (MAPK) pathway. Recent experimental studies have shown that beta-glucan recognition is mediated by co-receptor LysMPRR (lysin motif pattern recognition receptor)-CERK1 (chitin elicitor receptor kinase 1), LYK4, and LYK5 (LysM-containing receptor-like kinase), as well as different receptor systems in plants that could be plant species-specific and/or age and/or tissue-dependent. Transgenic overexpression of beta-glucanase, chitinase, and/or in combination with other PR-proteins like cationic peroxidase, AP24,thaumatin-likeprotein 1 (TLP-1) has also been achieved for improving plant disease resistance in crop plants, but the transgenic methods have some ethical and environmental concerns. In this regard, elicitation of plant immunity using biopolymer like beta-glucan and chitosan offers an economical, safe, and publicly acceptable method. The beta-glucan and chitosan nanocomposites have proven to be useful for the activation of plant defense pathways and to enhance plant response/systemic acquired resistance (SAR) against broad types of plant pathogens and mitigating multiple stresses under the changing climate conditions.

Automated summary

Beta-glucan, an eco-friendly and biodegradable biopolymer, plays important roles in crop plants by activating the innate immune system and enhancing plant disease resistance. It triggers a cascade of reactions, resulting in the accumulation of pathogenesis-related proteins, antioxidant defense enzymes, and activation of signaling pathways. Eliciting plant immunity using beta-glucan and chitosan offers an economical, safe, and publicly acceptable method to enhance plant defense and mitigate multiple stresses.