Mannan oligosaccharides trigger multiple defence responses in rice and tobacco as a novel danger‐associated molecular pattern

Abstract

Summary Oligosaccharide, a typical danger‐associated molecular pattern (DAMP), has been studied and applied as plant defence elicitor for several years. Here, we report a novel oligosaccharide, mannan oligosaccharide (MOS) with a degree of polymerization of 2–6, which was hydrolysed from locust bean gum by a newly reported enzyme, BpMan5. The MOS treatment can significantly enhance the generation of signalling molecules such as intracellular Ca 2+ and reactive oxygen species. Subsequent defence events like stomata closure and cell death were also caused by MOS, eventually leading to the prevention of pathogen invasion or expansion. Transcriptional expression assay indicated that MOS activated mitogen‐activated protein kinase cascades in tobacco and rice via different cascading pathways. The expression levels of the defence‐related genes PR‐1a and LOX were both up‐regulated after MOS treatment, suggesting that MOS may simultaneously activate salicylic acid and jasmonic acid‐dependent signalling pathways. Furthermore, liquid chromatography‐mass spectrometry analysis showed that MOS led to the accumulation of four phytoalexins (momilactone A, phytocassane A, phytocassane D, and phytocassane E) in rice seedling leaves within 12–24 h. Finally, MOS conferred resistance in rice and tobacco against Xanthomonas oryzae and Phytophthora nicotianae , respectively. Taken together, our results indicated that MOS, a novel DAMP, could trigger multiple defence responses to prime plant resistance and has a great potential as plant defence elicitor for the management of plant disease.

Arabinoxylan-Oligosaccharides Act as Damage Associated Molecular Patterns in Plants Regulating Disease Resistance

“…Anyway, in spite of the high doses required of these novel groups of hemicellulosic DAMPs to be perceived by plants as such, they were able to enhance plant protection against different plant pathogens. Xyloglucan effectively protected grapevine and Arabidopsis against the necrotrophic fungus Botrytis cinerea or the oomycete Hyaloperonospora arabidopsidis pathogens while mannans improved rice protection against the bacteria Xanthomonas oryzae and the oomycete Phytophthora nicotianae, respectively (Claverie et al, 2018;Zang et al, 2019). In this work we have shown the protection capacity of XA3XX on tomato and pepper plants against bacterial plant pathogen P. syringae and the fungus S. sclerotiorum (Figure 7).…”

“…Bearing in mind that the presence of glucuronoAXs has been suggested to be a component of Arabidopsis cell walls (Zablackis et al, 1995), XA3XX and related structures characterized in this work could be considered as plant DAMPs even in Arabidopsis model species. Structurally, the most similar plant DAMPs characterized so far would be other b-1,4-linked hemicelluloses such as xyloglucan and mannan (Claverie et al, 2018;Zang et al, 2019). Xyloglucan recently proposed as DAMP consists of a b-1,4-glucan backbone associated with xylosyl, galactosyl, and fucosyl-type branching, mainly of DP 7 (Claverie et al, 2018).…”

“…With around 20 different monosaccharide moieties building the polysaccharides of the plant cell wall, other carbohydrate-based cell wall molecules in addition to OGs and cello-oligosaccharides should have been selected by plants as DAMPs. In line with this hypothesis, recent works have also nominated xyloglucan and mannan cell wall-derived oligosaccharides as plant DAMPs ( Claverie et al., 2018 ; Zang et al., 2019 ), and β-1,3-glucan oligosaccharides present in plant callose but also in fungal cell walls, as dual DAMPs/MAMPs ( Mélida et al., 2018 ).…”

“…benthamiana and Oryza sativa (Zang et al, 2019). Mannan oligosaccharides triggered Ca 2+ influxes, ROS production, stomata closure, and over-expression of defense-related genes such as PR-1a and LOX.…”

Ultrahigh-activity immune inducer from Endophytic Fungi induces tobacco resistance to virus by SA pathway and RNA silencing

“…They can also be highly expressed in plants with the induction of SA [22,31,32]. PR-1A and nonexpressor of PR (NPR) are the key factors in the SA pathway, involved in N. benthamiana resistance to viruses [33] or other pathogens, such as phytophthora infestations [34]. WRKYs can bind the promoter region of NPR and have functions in the SA signaling pathway [35][36][37].…”