FGB1 and WSC3 are in planta‐induced β‐glucan‐binding fungal lectins with different functions

Abstract

Summary In the root endophyte Serendipita indica, several lectin‐like members of the expanded multigene family of WSC proteins are transcriptionally induced in planta and are potentially involved in β‐glucan remodeling at the fungal cell wall. Using biochemical and cytological approaches we show that one of these lectins, SiWSC3 with three WSC domains, is an integral fungal cell wall component that binds to long‐chain β1‐3‐glucan but has no affinity for shorter β1‐3‐ or β1‐6‐linked glucose oligomers. Comparative analysis with the previously identified β‐glucan‐binding lectin SiFGB1 demonstrated that whereas SiWSC3 does not require β1‐6‐linked glucose for efficient binding to branched β1‐3‐glucan, SiFGB1 does. In contrast to SiFGB1, the multivalent SiWSC3 lectin can efficiently agglutinate fungal cells and is additionally induced during fungus–fungus confrontation, suggesting different functions for these two β‐glucan‐binding lectins. Our results highlight the importance of the β‐glucan cell wall component in plant–fungus interactions and the potential of β‐glucan‐binding lectins as specific detection tools for fungi in vivo.

A secreted fungal histidine‐ and alanine‐rich protein regulates metal ion homeostasis and oxidative stress

“…5c, d), suggesting that iron chelation alone does not fully explain the effect of Dld1 activity. In contrast to Dld1, the recombinant S. indica effector FGB1 (Wawra et al, 2016(Wawra et al, , 2019) (Methods S1) did not affect DAB oxidation and polymerization ( Fig. 5d,e).…”

“…To compare the activity of Dld1 with that of the S. indica effector FGB1 (Wawra et al, 2016(Wawra et al, , 2019; Methods S1), which served as negative control, purified proteins were dialyzed overnight against 5 l of 50 mM MES containing 150 mM NaCl, pH 6. DAB, H 2 O 2 and PRX stock solutions for this experiment were freshly prepared in the dialysis buffer.…”

The Ustilago hordei–Barley Interaction is a Versatile System for Characterization of Fungal Effectors

“…Chemically fixed samples were prepared according to Wawra et al [31] with minor changes. For TEM observation, 2 mm leaf discs from infected and non-infected Hordeum vulgare leaves were excised from 1 cm below infection sites by using a biopsy punch and chemically fixed in 2.5% glutaraldehyde and 2% paraformaldehyde in 0.05 M sodium cacodylate buffer, pH 6.9, supplemented with 0.025% CaCl 2 (w/v) for 2 h at room temperature.…”

Fungi hijack a plant apoplastic endoglucanase to release a ROS scavenging β-glucan decasaccharide to subvert immune responses

“…Surface exposed and accessible fungal polysaccharides are hydrolyzed by apoplastic CAZymes, such as chitinases and glucanases and the resulting oligosaccharides can act as elicitors to trigger plant immune responses (Rovenich et al , 2016). Recently, we described a soluble extracellular β-glucan matrix produced by endophytic fungi during root colonization of Arabidopsis thaliana (hereafter Arabidopsis) and barley (Wawra et al , 2019). Very little is known about the biochemical properties, composition and function of this EPS matrix, but its detection in beneficial and pathogenic fungi strongly suggests a conserved role in counteracting environmental and immunological challenges during plant colonization (Wanke et al , 2021).…”