Thomas S L, Bonello P, Lipps P E, Boehm M J
Department of Plant Pathology, The Ohio State University, Columbus 43210.
Department of Plant Pathology, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691.
Plant Dis. 2006 Jan;90(1):33-38. doi: 10.1094/PD-90-0033.
Avenacinase activity has been shown to be a key factor determining the host range of Gaeumannomyces graminis on oats (Avena sativa). G. graminis var. avenae produces avenacinase, which detoxifies the oat root saponin avenacin, enabling it to infect oats. G. graminis var. tritici does not produce avenacinase and is unable to infect oats. G. graminis var. avenae is also reported to incite take-all patch on creeping bentgrass (Agrostis stolonifera). It is unknown whether creeping bentgrass produces avenacin and if the avenacin-avenacinase interaction influences G. graminis pathogenicity on creeping bentgrass. The root extracts of six creeping bentgrass cultivars were analyzed by fluorimetry, thin-layer chromatography, and high performance liquid chromatography for avenacin content. Avenacin was not detected in any creeping bentgrass cultivars, and pathogenicity assays confirmed that both G. graminis var. avenae and G. graminis var. tritici can infect creeping bentgrass and wheat (Triticum aestivum), but only G. graminis var. avenae incited disease on oats. These results are consistent with the root analyses and confirm that avenacinase activity is not required for creeping bentgrass infection by G. graminis.
燕麦 avenacinase 活性已被证明是决定禾顶囊壳菌燕麦变种（Gaeumannomyces graminis var. avenae）寄主范围的关键因素。禾顶囊壳菌燕麦变种能产生 avenacinase，该酶可使燕麦根皂苷 avenacin 解毒，从而使其能够感染燕麦。禾顶囊壳菌小麦变种（G. graminis var. tritici）不产生 avenacinase，无法感染燕麦。据报道，禾顶囊壳菌燕麦变种还会引发匍匐翦股颖（Agrostis stolonifera）的全蚀病斑。尚不清楚匍匐翦股颖是否产生 avenacin，以及 avenacin-avenacinase 相互作用是否会影响禾顶囊壳菌对匍匐翦股颖的致病性。通过荧光法、薄层色谱法和高效液相色谱法对六个匍匐翦股颖品种的根提取物进行了 avenacin 含量分析。在任何匍匐翦股颖品种中均未检测到 avenacin，致病性测定证实，禾顶囊壳菌燕麦变种和禾顶囊壳菌小麦变种均可感染匍匐翦股颖和小麦（Triticum aestivum），但只有禾顶囊壳菌燕麦变种会引发燕麦病害。这些结果与根部分析结果一致，并证实禾顶囊壳菌感染匍匐翦股颖不需要 avenacinase 活性。
