Emerging Roles of β-Glucanases in Plant Development and Adaptative Responses

Abstract

Plant β-glucanases are enzymes involved in the synthesis, remodelling and turnover of cell wall components during multiple physiological processes. Based on the type of the glycoside bond they cleave, plant β-glucanases have been grouped into three categories: (i) β-1,4-glucanases degrade cellulose and other polysaccharides containing 1,4-glycosidic bonds to remodel and disassemble the wall during cell growth. (ii) β-1,3-glucanases are responsible for the mobilization of callose, governing the symplastic trafficking through plasmodesmata. (iii) β-1,3-1,4-glucanases degrade mixed linkage glucan, a transient wall polysaccharide found in cereals, which is broken down to obtain energy during rapid seedling growth. In addition to their roles in the turnover of self-glucan structures, plant β-glucanases are crucial in regulating the outcome in symbiotic and hostile plant–microbe interactions by degrading non-self glucan structures. Plants use these enzymes to hydrolyse β-glucans found in the walls of microbes, not only by contributing to a local antimicrobial defence barrier, but also by generating signalling glucans triggering the activation of global responses. As a counterpart, microbes developed strategies to hijack plant β-glucanases to their advantage to successfully colonize plant tissues. This review outlines our current understanding on plant β-glucanases, with a particular focus on the latest advances on their roles in adaptative responses.

Protective and Curative Activities of Paenibacillus polymyxa against Zucchini yellow mosaic virus Infestation in Squash Plants

“…The PR-2 gene family includes the β -1,3-glucanases that hydrolyze and modify β-glucan, which is a dominant sugar in plant cells and several invading microbes [ 77 ]. The released β-glucan units signaled the plant resistance state and enhanced the production of plant phytoalexins as antimicrobial agents [ 78 , 79 ].…”

Xylanase Inhibitors: Defense Players in Plant Immunity with Implications in Agro-Industrial Processing

“…In the primary cell wall of graminaceous monocot plants, the most abundant hemicellulose is arabinoxylan, a polysaccharide composed of a backbone of β-1,4-D-xylose substituted with arabinose and, less frequently, with glucuronic acid, methylglucuronic acid, and acetyl side groups in a non-repeating fashion [ 13 ]. The most abundant hemicellulose in the dicot primary cell wall is xyloglucan, a linear D-glucose backbone linked by β-1,4-bridges substituted at regular sites with D-xylosyl residues [ 14 ] and further extended by galactosyl, fucosyl, or arabinosyl residues [ 15 ]. Overall, the degree of substitutions and the side chains vary considerably between plant species and cell types [ 13 ].…”

The multifaceted roles of R2R3 transcription factor HlMYB7 in the regulation of flavonoid and bitter acids pathways, development and biotic stress in hop (Humulus lupulus L.)

“…Unexpectedly, CONSTANS-LIKE ( COL ) and CCT domain-containing genes that play important roles in photoperiod signalling and flowering time modulation (Chen et al, 2021) exhibited reduced expression. Furthermore, we also noticed that DEGs involved in host immune responses such as patatin-like protein 2 (La Camera et al, 2009), pathogenesis-related protein 4 (PR-4), PR-5 (Guevara-Morato et al, 2010), including TIFY proteins (Zhang et al, 2020), β-glucanases, chitinase-like (CTL) proteins (Perrot et al, 2022), leucine-rich repeat receptor kinases (Torii, 2004) which regulate a variety of developmental and defence-related processes, were downregulated (Supplemental Table S3). qRT-PCR analysis of some of these genes, including ten randomly selected DEGs (five up-regulated and five down-regulated genes) was consistent with the results of the RNA-seq data (Supplemental Figure S2), demonstrating the reproducibility of the transcriptome data.…”