Identification of a new virulence locus in Agrobacterium tumefaciens that affects polysaccharide composition and plant cell attachment.
Identification of a new virulence locus in Agrobacterium tumefaciens that affects polysaccharide composition and plant cell attachment.
复制标题
鉴定根癌农杆菌中影响多糖组成和植物细胞附着的新毒力位点。
DOI：
10.1128/jb.169.7.3209-3216.1987
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发表时间：
1987
影响因子：
3.2
通讯作者：
Hurlbert,RE
中科院分区：
文献类型：
--
作者：
Thomashow,MF;Karlinsey,JE;Marks,JR;Hurlbert,RE
我们在根癌农杆菌中发现了一个新的毒力基因座。在该位点携带Tn5插入片段的菌株不能对大青烟、黄花烟草、烟草和向日葵产生致瘤作用，对胡萝卜盘上的致病力有严重的抑制作用。我们将该基因座命名为PSCA，因为定义该基因座的突变体最初被分离出来时具有改变的多糖组成；它们在含有利血磷或硫代氟的培养基上是非荧光的，表明纤维素纤维的生产存在缺陷。进一步的分析表明，野生型菌株合成的四种胞外多糖中，PscA突变体几乎没有产生。DNA杂交分析和遗传互补实验表明，PSCA基因座不是由Ti质粒编码的，它与已报道的染色体毒力基因Chva和ChvB不同。然而，像chva和chvB突变体一样，PSCA突变体不能形成肿瘤显然是由于植物细胞附着的缺陷。虽然我们可以证明野生型菌株与烟草悬浮细胞的结合，但PSCA突变体的附着显著减少或完全消失。
We have identified a new virulence locus in Agrobacterium tumefaciens. Strains carrying Tn5 inserts at this locus could not incite tumors on Kalanchoe daigremontiana, Nicotiana rustica, tobacco, or sunflower and had severely attenuated virulence on carrot disks. We termed the locus pscA, because the mutants that defined the locus were initially isolated as having an altered polysaccharide composition; they were nonfluorescent on media containing Leucophor or Calcofluor, indicating a defect in the production of cellulose fibrils. Further analysis showed that the pscA mutants produced little, if any, of the four species of exopolysaccharide synthesized by the wild-type strain. DNA hybridization analysis and genetic complementation experiments indicated that the pscA locus is not encoded by the Ti plasmid and that it is distinct from the previously described chromosomal virulence loci chvA and chvB. However, like chvA and chvB mutants, the inability of the pscA mutants to form tumors is apparently due to a defect in plant cell attachment. Whereas we could demonstrate binding of the wild-type strain to tobacco suspension cells, attachment of the pscA mutants was drastically reduced or completely absent.