The mechanisms of hyphal pellet formation mediated by polysaccharides, α-1,3-glucan and galactosaminogalactan, in Aspergillus species
The mechanisms of hyphal pellet formation mediated by polysaccharides, α-1,3-glucan and galactosaminogalactan, in Aspergillus species
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DOI：
10.1186/s40694-020-00101-4
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发表时间：
2020-07-01
影响因子：
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通讯作者：
Abe, Keietsu
中科院分区：
文献类型：
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作者：
Miyazawa, Ken;Yoshimi, Akira;Abe, Keietsu
丝状真菌广泛用于生产酶和化学品，并且在液体和固体培养物中工业化培养。液体深层培养是丝状真菌的液体培养。在液体培养中，丝状真菌表现出不同的宏观形态，如菌丝球和分散的菌丝取决于培养条件和真菌菌株的遗传背景。虽然宏观形态极大地影响了生产力的淹没文化，具体的细胞成分需要菌丝聚集分生孢子萌发后还没有得到表征。最近，我们报道了初生细胞壁多糖α-1，3-葡聚糖和胞外多糖半乳糖胺半乳聚糖（GAG）有助于曲霉菌丝聚集，α-1，3-葡聚糖和GAG缺陷的菌株在液体培养中显示分散的菌丝。在这篇综述中，我们总结了我们目前的理解的贡献的化学性质的α-1，3-葡聚糖和糖胺聚糖菌丝聚集。多种子囊菌和担子菌具有α-1，3-葡聚糖合酶基因。此外，一些盘菌亚门真菌，包括用于发酵工业的物种，也具有GAG生物合成基因。我们还在这里综述了已知的α-1，3-葡聚糖和GAG的生物合成机制。调节这两种多糖的生物合成可能是控制菌丝球形成的一种潜在方法。
Filamentous fungi are widely used for production of enzymes and chemicals, and are industrially cultivated both in liquid and solid cultures. Submerged culture is often used as liquid culture for filamentous fungi. In submerged culture, filamentous fungi show diverse macromorphology such as hyphal pellets and dispersed hyphae depending on culture conditions and genetic backgrounds of fungal strains. Although the macromorphology greatly affects the productivity of submerged cultures, the specific cellular components needed for hyphal aggregation after conidial germination have not been characterized. Recently we reported that the primary cell wall polysaccharide alpha-1,3-glucan and the extracellular polysaccharide galactosaminogalactan (GAG) contribute to hyphal aggregation in Aspergillus oryzae, and that a strain deficient in both alpha-1,3-glucan and GAG shows dispersed hyphae in liquid culture. In this review, we summarize our current understanding of the contribution of chemical properties of alpha-1,3-glucan and GAG to hyphal aggregation. Various ascomycetes and basidiomycetes have alpha-1,3-glucan synthase gene(s). In addition, some Pezizomycotina fungi, including species used in the fermentation industry, also have GAG biosynthetic genes. We also review here the known mechanisms of biosynthesis of alpha-1,3-glucan and GAG. Regulation of the biosynthesis of the two polysaccharides could be a potential way of controlling formation of hyphal pellets.