Glucanase-Induced Stipe Wall Extension Shows Distinct Differences from Chitinase-Induced Stipe Wall Extension of Coprinopsis cinerea

Abstract

This study reports that a high concentration of the endo-β-1,3-glucanase ENG (200 μg ml−1) induced heat-inactivated stipe wall extension of Coprinopsis cinerea, whereas a high concentration of the extracellular β-glucosidase BGL2 (1,000 μg ml−1) did not; however, in combination, low concentrations of ENG (25 μg ml−1) and BGL2 (260 μg ml−1) induced heat-inactivated stipe cell wall extension. In contrast to the previously reported chitinase-reconstituted stipe wall extension, β-1,3-glucanase-reconstituted heat-inactivated stipe cell wall extension initially exhibited a fast extension rate that quickly decreased to zero after approximately 60 min; the stipe cell wall extension induced by a high concentration of β-1,3-glucanase did not result in stipe breakage during measurement, and the inner surfaces of glucanase-reconstituted extended cell walls still remained as amorphous matrices that did not appear to have been damaged. These distinctive features of the β-1,3-glucanase-reconstituted wall extension may be because chitin chains are cross-linked not only to the nonreducing termini of the side chains and the backbones of β-1,6 branched β-1,3-glucans but also to other polysaccharides. Remarkably, a low concentration of either the β-1,3-glucanase ENG or of chitinase ChiE1 did not induce heat-inactivated stipe wall extension, but a combination of these two enzymes, each at a low concentration, showed stipe cell wall extension activity that exhibited a steady and continuous wall extension profile. Therefore, we concluded that the stipe cell wall extension is the result of the synergistic actions of glucanases and chitinases. IMPORTANCE We previously reported that the chitinase could induce stipe wall extension and was involved in stipe elongation growth of the mushroom Coprinopsis cinerea. In this study, we explored that β-1,3-glucanase also induced stipe cell wall extension. Interestingly, the extension profile and extended ultra-architecture of β-1,3-glucanase-reconstituted stipe wall were different from those of chitinase-reconstituted stipe wall. However, β-1,3-glucanase cooperated with chitinase to induce stipe cell wall extension. The significance of this synergy between glucanases and chitinases is that it enables a low concentration of active enzymes to induce wall extension, and the involvement of β-1,3-glucanases is necessary for the cell wall remodeling and the addition of new β-glucans during stipe elongation growth.

The extracellular β-glucosidase BGL2 has two variants with different molecular sizes and hydrolytic activities in the stipe or pilei of Coprinopsis cinerea

“…We previously reported that BGL2 performs different physiological functions in stipe elongation and pilei autolysis of C. cinerea [3,12,14]. In the early stage of fruiting-body development, the physiological role of BGL2 in the elongating stipe is to keep the stipe cellwall plastic and synergize with other glucanohydrolases and chitinases to induce wall extension [12,14]. During this stage, excessive hydrolytic activity of β-glucosidase will destroy the structure of the cell wall and affect the elongation of the stipe [12].…”

Seaweed-Based Products and Mushroom β-Glucan as Tomato Plant Immunological Inducers

“…The β-1,3-glucanase induces the stipe wall extension activity in the fungi [ 53 ]. It was also reported that extracts from the brown seaweed Laminaria digitata can induce plant systemic resistance.…”

A 21st century miniguide to sporophore morphogenesis and development in Agaricomycetes and their biotechnological potential

“…In Coprinopsis cinerea and Coprinus comatus development-related increases in the activities of glucosidase and glucanases, protease and chitinase have been noted during cap expansion (Iten, 1970;Iten & Matile, 1970;Bush, 1974); so, degradation of the substance of the spent gill tissue is provided for by specific enzyme derepression. Whilst in the stipe, specific chitinases and glucanases act synergistically in cell wall extension of C. cinerea (Kang et al, 2019a;Zhou et al, 2019). In earlier stages, prior to the onset of autodigestion, a number of enzymes are specifically derepressed as tissues of the C. cinerea mushroom cap begin to form (Moore, 2013b).…”