Stefanato Francesca L, Abou-Mansour Eliane, Buchala Antony, Kretschmer Matthias, Mosbach Andreas, Hahn Matthias, Bochet Christian G, Métraux Jean-Pierre, Schoonbeek Henk-jan
Department of Biology, University of Fribourg, Chemin du Musée 8, CH-1700 Fribourg, Switzerland.
Plant J. 2009 May;58(3):499-510. doi: 10.1111/j.1365-313X.2009.03794.x. Epub 2008 Jan 18.
Arabidopsis thaliana is known to produce the phytoalexin camalexin in response to abiotic and biotic stress. Here we studied the mechanisms of tolerance to camalexin in the fungus Botrytis cinerea, a necrotrophic pathogen of A. thaliana. Exposure of B. cinerea to camalexin induces expression of BcatrB, an ABC transporter that functions in the efflux of fungitoxic compounds. B. cinerea inoculated on wild-type A. thaliana plants yields smaller lesions than on camalexin-deficient A. thaliana mutants. A B. cinerea strain lacking functional BcatrB is more sensitive to camalexin in vitro and less virulent on wild-type plants, but is still fully virulent on camalexin-deficient mutants. Pre-treatment of A. thaliana with UV-C leads to increased camalexin accumulation and substantial resistance to B. cinerea. UV-C-induced resistance was not seen in the camalexin-deficient mutants cyp79B2/B3, cyp71A13, pad3 or pad2, and was strongly reduced in ups1. Here we demonstrate that an ABC transporter is a virulence factor that increases tolerance of the pathogen towards a phytoalexin, and the complete restoration of virulence on host plants lacking this phytoalexin.
已知拟南芥会在应对非生物和生物胁迫时产生植物抗毒素camalexin。在此，我们研究了灰葡萄孢菌（一种拟南芥的坏死营养型病原体）对camalexin的耐受机制。将灰葡萄孢菌暴露于camalexin会诱导BcatrB的表达，BcatrB是一种ABC转运蛋白，在真菌毒性化合物的外排中起作用。接种在野生型拟南芥植株上的灰葡萄孢菌产生的病斑比接种在缺乏camalexin的拟南芥突变体上的病斑小。一株缺乏功能性BcatrB的灰葡萄孢菌在体外对camalexin更敏感，在野生型植株上的毒性更低，但在缺乏camalexin的突变体上仍具有完全毒性。用UV-C对拟南芥进行预处理会导致camalexin积累增加，并对灰葡萄孢菌产生显著抗性。在缺乏camalexin的突变体cyp79B2/B3、cyp71A13、pad3或pad2中未观察到UV-C诱导的抗性，在ups1中抗性大幅降低。在此，我们证明一种ABC转运蛋白是一种毒力因子，它增加了病原体对植物抗毒素的耐受性，并使在缺乏这种植物抗毒素的宿主植物上的毒力完全恢复。
