The presence of a novel type of surface polysaccharide in Rhizobium meliloti requires a new fatty acid synthase-like gene cluster involved in symbiotic nodule development.
The presence of a novel type of surface polysaccharide in Rhizobium meliloti requires a new fatty acid synthase-like gene cluster involved in symbiotic nodule development.
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苜蓿根瘤菌中存在一种新型表面多糖，需要一种新的脂肪酸合酶样基因簇参与共生根瘤的发育。
DOI：
10.1111/j.1365-2958.1993.tb01653.x
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发表时间：
1993
影响因子：
3.6
通讯作者：
Kondorosi,A
中科院分区：
文献类型：
--
作者：
Petrovics,G;Putnoky,P;Reuhs,B;Kim,J;Thorp,TA;Noel,KD;Carlson,RW;Kondorosi,A
细菌胞外多糖(EPS)和脂多糖(LPS)分子在植物-细菌相互作用中发挥着重要作用。在这里，我们证明了FIX-23基因座，它补偿了共生根瘤发育过程中的突变，参与了一种新的多糖的产生，这种多糖富含3-脱氧-Dmanno-2-辛酸(Kdo)，但不是经典的脂多糖。这个分子可能是一个表面抗原，因为整个苜蓿根瘤菌的抗血清与它发生强烈的反应，而且由于INFIX-23的突变导致不能产生这种多糖并与噬菌体16-3结合。这种富含Kdo的多糖很可能类似于某些通过磷脂部分固定在膜上的Escherichia coliK-抗原。对该区域一个基因簇的DNA序列分析表明，预测的6个基因的蛋白质产物与大鼠脂肪酸合成酶多功能酶结构域的蛋白质产物具有高度的同源性和相似的组织结构。
Bacterial exopolysaccharide (EPS) and lipopolysaccharide (LPS) molecules have been shown to play important roles in plant‐bacterium interactions. Here we have demonstrated that thefix‐23 loci, which compensate forexomutations during symbiotic nodule development, are involved in the production of a novel polysaccharide that is rich in 3‐deoxy‐Dmanno‐2‐octulosonic acid (Kdo) but is not the classical LPS. This molecule is likely to be a surface antigen since antiserum to wholeRhizobium meliloticells reacts strongly with it, and since mutations infix‐23 result in an inability to produce this polysaccharide and to bind bacteriophage 16‐3. It is likely that this Kdo‐rich polysaccharide is analogous to certainEscherichia coliK‐antigens which are anchored to the membrane via a phospholipid moiety. DNA sequence analysis of one gene cluster of this region revealed that the predicted protein products of six genes exhibit a high degree of homology and similar organization to those of the rat fatty acid synthase multifunctional enzyme domains.