Mode of action of the Arabidopsis thaliana phytoalexin camalexin and its role in Arabidopsis-pathogen interactions
Mode of action of the Arabidopsis thaliana phytoalexin camalexin and its role in Arabidopsis-pathogen interactions
复制标题
DOI：
10.1094/mpmi-9-0748
复制
发表时间：
1996-11-01
影响因子：
3.5
通讯作者：
Ausubel, FN
中科院分区：
文献类型：
--
作者：
Rogers, EE;Glazebrook, J;Ausubel, FN
拟南芥致病菌假单胞菌致病变种（Pseudomonasseringae pv.）斑壳菌E54326（Psm E54326）和其它革兰氏阴性细菌对camalexin（3-噻唑-2 '-基-吲哚）敏感，而拟南芥植物抗毒素（Arabidopsis phytoalexin）Furtfiermore、Psm E54326不能降解camalexin或变得对camalexin耐受。膜完整性的测定显示，与其他植物抗毒素一样，Camalexin破坏细菌膜，表明Camalexin毒性是膜破坏的结果。对Psm ES 4326的Camalexin抗性突变体进行筛选，仅得到部分抗性突变体，其在杀伤和膜完整性测定中均显示部分抗性。这些突变体还对低浓度四环素和萘啶酸具有抗性，表明它们的外膜组分受到影响。Camalexin对组织培养中生长的拟南芥细胞是有毒的，然而，与野生型拟南芥和Camalexin缺陷突变体的受感染叶片中的疾病症状相关的细胞死亡的程度的比较表明，Camalexin对受感染组织中的细胞死亡没有显著贡献。
The virulent Arabidopsis thaliana pathogen Pseudomonas syringae pv. maculicola strain E54326 (Psm E54326) and other gram-negative bacteria are sensitive to camalexin (3-thiazol-2'-yl-indole), the Arabidopsis phytoalexin, Furtfiermore, Psm E54326 is unable to degrade camalexin or to become tolerant to it. Apparently, Psm E54326 is a successful pathogen even though it elicits synthesis of a host phytoalexin to which it is sensitive. Assays of membrane integrity revealed that, like other phytoalexins, camalexin disrupts bacterial membranes, suggesting that camalexin toxicity is a consequence of membrane disruption. A screen for camalexin-resistant mutants of Psm ES4326 yielded only partially resistant mutants, which displayed partial resistance in both killing and membrane integrity assays, These mutants were also resistant to low concentrations of tetracycline and nalidixic acid, suggesting that they were affected in components of the outer membrane, The mutants were not distinguishable from Psm ES4326 in virulence assays, Camalexin was toxic to Arabidopsis cells growing in tissue culture, However, comparison of the extent of cell death associated with disease symptoms in infected leaves of wild-type Arabidopsis and a camalexin-deficient mutant suggested that camalexin does not contribute significantly to cell death in infected tissue.