Identification of the Vb Gene Which Confers Sensitivity to the Host-Selective Toxin, Victorin

9631442燕麦的沃尔伯特维多利亚枯萎病是由真菌Cochliobolus victoriae引起的。这种真菌是致病的，因为它产生宿主特有的毒素Victorin。在宿主中，对Victorin的敏感性，从而对病原体的敏感性，是由VB基因座上的显性等位基因决定的。据推测，VB基因通过编码毒素“受体”(作用部位)来调节敏感性，该受体在毒素敏感品系(敏感品系)中起作用，而在毒素不敏感品系中缺失或改变。该毒素具有生物活性的标记衍生物已被用于鉴定只在毒素敏感(敏感)燕麦中结合Victorin的100 kDa蛋白质和在敏感和抗性基因中都结合Victorin的15 kDa蛋白质。100 kDa的Victorin结合蛋白(VBP)是线粒体多酶复合体甘氨酸脱羧酶的P蛋白组分。结果还表明，甘氨酸脱羧酶复合体(GDC)的15 kDa H蛋白成分为VBP。这项研究将测试一个生化模型，即毒素特异性由两个Victorin结合蛋白，即GDC的P-和H-蛋白成分的相互作用来调节。这些结果将为了解寄主特异性毒素依赖型植物病害的性质提供新的信息，这可能导致新的作物保护策略。

9631442 Wolpert Victoria blight of oats is caused by the fungus Cochliobolus victoriae. This fungus is pathogenic because it produces the host-specific toxin, victorin. In the host, sensitivity to victorin, and thus, susceptibility to the pathogen, is conditioned by the dominant allele at the Vb locus. It has been hypothesized that the Vb gene conditions susceptibility by coding for a toxin "receptor" (site of action) which is functional in toxin-sensitive lines (susceptible lines) and either absent or altered in toxin-insensitive lines. Biologically-active, labeled derivatives of the toxin have been used to identify and 100 kDa protein that binds victorin only in toxin-sensitive (susceptible) genotypes of oats and a 15 kDa protein that binds victorin in both susceptible and resistant genotypes. The 100 kDa victorin-binding protein (VBP) has been identified as the P-protein component of the nuclear-encoded, mitochondrial multienzyme complex, glycine decarboxylase. Results have also indicated that the 15 kDa H-protein component of the glycine decarboxylase complex (GDC) is a VBP. This research will test a biochemical model that toxin specificity is regulated by the interaction of the two victorin binding proteins, the P- and the H-protein components of the GDC. The results will provide new information about the nature of Host-specific toxin dependent plant disease, which may lead to a new crop protection strategy.