The β-1,3-glucan synthase gene GFGLS2 plays major roles in mycelial growth and polysaccharide synthesis in Grifola frondosa.

Li-Hua Jiang, Xiang-Fei Li, Xin-Yi Zan, Xin Fu, Feng-Jie Cui, Hong-An Zhu, Wen-Jing Sun, Ting-Lei Tao

Applied microbiology and biotechnology 2022 Jan

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β-1,3-Glucans are well-known biological and health-promoting compounds in edible fungi. Our previous results characterized a glucan synthase gene (GFGLS) of Grifola frondosa for the first time to understand its role in mycelial growth and glucan biosynthesis. In the present study, we identified and functionally reannotated another glucan synthase gene, GFGLS2, based on our previous results. GFGLS2 had a full sequence of 5944 bp including 11 introns and 12 exons and a coding information for 1713 amino acids of a lower molecular weight (195.2 kDa) protein with different conserved domain sites than GFGLS (5927 bp with also 11 introns and a coding information for 1781 aa). Three dual-promoter RNA-silencing vectors, pAN7-iGFGLS-dual, pAN7-iGFGLS2-dual, and pAN7-CiGFGLS-dual, were constructed to downregulate GFGLS, GFGLS2, and GFGLS/GFGLS2 expression by targeting their unique exon sequence or conserved functional sequences. Silencing GFGLS2 resulted in higher downregulation efficiency than silencing GFGLS. Cosilencing GFGLS and GFGLS2 had a synergistic downregulation effect, with slower mycelial growth and glucan production by G. frondosa. These findings indicated that GFGLS2 plays major roles in mycelial growth and polysaccharide synthesis and provides a reference to understand the biosynthesis pathway of mushroom polysaccharides. KEY POINTS: • The 5944-bp glucan synthase gene GFGLS2 of G. frondosa was cloned and reannotated • GFGLS2 showed identity and significant differences with the previously identified GFGLS • GFGLS2 played a major role in fermentation and glucan biosynthesis. © 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Citation

Li-Hua Jiang, Xiang-Fei Li, Xin-Yi Zan, Xin Fu, Feng-Jie Cui, Hong-An Zhu, Wen-Jing Sun, Ting-Lei Tao. The β-1,3-glucan synthase gene GFGLS2 plays major roles in mycelial growth and polysaccharide synthesis in Grifola frondosa. Applied microbiology and biotechnology. 2022 Jan;106(2):563-578