The presence of genes for glycosyl hydrolases in many Acidobacteria genomes indicates an important role in the degradation of plant cell wall material. Acidobacteria bacterium AB60 was obtained from Cerrado oligotrophic soil in Brazil, where this phylum is abundant. The 16S rRNA gene analyses showed that AB60 was closely related to the genera Occallatibacter and Telmatobacter. However, AB60 grew on xylan as carbon source, which was not observed in Occallatibacter species; but growth was not detected on medium containing carboxymethyl cellulose, as observed in Telmatobacter. Nevertheless, the genome analysis of AB60 revealed genes for the enzymes involved in cellulose as well as xylan degradation. In addition to enzymes involved in xylan degradation, α-l-rhamnosidase was detected in the cultures of AB60. Functional screening of a small-insert genomic library did not identify any clones capable of carboxymethyl cellulose degradation, but open reading frames coding α-l-arabinofuranosidase and α-l-rhamnosidase were present in clones showing xylan degradation halos. Both enzymes act on the lateral chains of heteropolymers such as pectin and some hemicelluloses. These results indicate that the hydrolysis of α-linked sugars may offer a metabolic niche for slow-growing Acidobacteria, allowing them to co-exist with other plant-degrading microbes that hydrolyze β-linked sugars from cellulose or hemicellulose backbones.

中文翻译：

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揭示 Cerrado 土壤中酸杆菌 AB60 的木聚糖分解潜力。

许多酸杆菌基因组中糖基水解酶基因的存在表明在植物细胞壁材料的降解中起重要作用。酸杆菌 AB60 是从巴西的 Cerrado 贫营养土壤中获得的，在那里这个门很丰富。16S rRNA基因分析表明AB60与Occalatibacter和Telmatobacter属密切相关。然而，AB60 以木聚糖为碳源生长，这在Occalatibacter物种中未观察到；但在含有羧甲基纤维素的培养基上未检测到生长，如在Telmatobacter 中观察到的. 尽管如此，AB60 的基因组分析揭示了参与纤维素和木聚糖降解的酶的基因。除了参与木聚糖降解酶，α -1-鼠李糖苷酶在AB60的培养物中检测到。小插入基因组文库的功能筛选没有发现任何能够降解羧甲基纤维素的克隆，但编码α- l-阿拉伯呋喃糖苷酶和α- l的开放阅读框-鼠李糖苷酶存在于显示木聚糖降解晕圈的克隆中。这两种酶都作用于杂聚物的侧链，如果胶和一些半纤维素。这些结果表明，α-连接糖的水解可能为缓慢生长的酸杆菌提供一个代谢生态位，使它们能够与其他植物降解微生物共存，这些微生物从纤维素或半纤维素骨架中水解 β-连接糖。