Laboratory of Biochemistry, Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, Saratov 410049, Russia.
Microbiol Res. 2011 Oct 20;166(7):585-93. doi: 10.1016/j.micres.2011.01.002. Epub 2011 Feb 21.
Azospirillum brasilense SR55, isolated from the rhizosphere of Triticum durum, was classified as serogroup II on the basis of serological tests. Such serogroup affiliation is uncharacteristic of wheat-associated Azospirillum species. The lipid A of A. brasilense SR55 lipopolysaccharide contained 3-hydroxytetradecanoic, 3-hydroxyhexadecanoic, hexadecanoic and octadecenoic fatty acids. The structure of the lipopolysaccharide's O polysaccharide was established, with the branched octasaccharide repeating unit being represented by l-rhamnose, l-3-O-Me-rhamnose, d-galactose and d-glucuronic acid. The SR55 lipopolysaccharide induced deformations of wheat root hairs. The lipopolysaccharide was not involved in bacterial cell aggregation, but its use to pretreat wheat roots was conducive to cell adsorption. This study shows that Azospirillum bacteria can utilise their own lipopolysaccharide as a carbon source, which may give them an advantage in competitive natural environments.
从硬粒小麦根际分离到的慢生根瘤菌（Azospirillum brasilense）SR55 基于血清学试验被分类为血清 II 群。这种血清群归属与小麦相关的根瘤菌属物种不同。慢生根瘤菌 SR55 脂多糖的脂 A 含有 3-羟基十四烷酸、3-羟基十六烷酸、十六烷酸和十八烯酸。脂多糖的 O-多糖结构被建立，支化的八糖重复单元由 l-鼠李糖、l-3-O-Me-鼠李糖、d-半乳糖和 d-葡萄糖醛酸组成。SR55 脂多糖诱导小麦根毛变形。脂多糖不参与细菌细胞聚集，但它用于预处理小麦根有利于细胞吸附。本研究表明，根瘤菌可以利用自身的脂多糖作为碳源，这可能使它们在竞争激烈的自然环境中具有优势。
