Cell wall‐derived mixed‐linked β‐1,3/1,4‐glucans trigger immune responses and disease resistance in plants

Pattern-triggered immunity (PTI) is activated in plants upon recognition by pattern receptors (PRRs) of damage- and microbe-associated molecular patterns (DAMPs MAMPs) derived from or microorganisms, respectively. To understand better the plant mechanisms involved perception carbohydrate-based structures recognized as DAMPs/MAMPs, we have studied ability mixed-linked β-1,3/1,4-glucans (MLGs), present some microbial cell walls, to trigger immune responses disease resistance plants. A range MLG were tested for their capacity induce PTI hallmarks, such cytoplasmic Ca2+ elevations, reactive oxygen species production, phosphorylation mitogen-activated protein kinases gene transcriptional reprogramming. These analyses revealed that oligosaccharides are perceived Arabidopsis thaliana identified a trisaccharide, β-d-cellobiosyl-(1,3)-β-d-glucose (MLG43), smallest structure triggering strong responses. MLG43-mediated partially dependent on LysM PRRs CERK1, LYK4 LYK5, they weaker cerk1 lyk4 lyk5 mutants than wild-type Cross-elicitation experiments between MLG43 carbohydrate MAMP chitohexaose [β-1,4-d-(GlcNAc)6], which also these PRRs, indicated mechanism could differ chitohexaose, fully impaired treatment confers enhanced A. oomycete Hyaloperonospora arabidopsidis tomato pepper different bacterial fungal pathogens. Our data support classification MLGs group resistance.