Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA.
Mol Plant Microbe Interact. 2013 Aug;26(8):903-17. doi: 10.1094/MPMI-01-13-0014-R.
Victoria blight, caused by Cochliobolus victoriae, is a disease originally described on oat and recapitulated on Arabidopsis. C. victoriae pathogenesis depends upon production of the toxin victorin. In oat, victorin sensitivity is conferred by the Vb gene, which is genetically inseparable from the Pc2 resistance gene. Concurrently, in Arabidopsis, sensitivity is conferred by the LOCUS ORCHESTRATING VICTORIN EFFECTS1 (LOV1) gene. LOV1 encodes a nucleotide-binding site leucine-rich repeat protein, a type of protein commonly associated with disease resistance, and LOV1 "guards" the defense thioredoxin, TRX-h5. Expression of LOV1 and TRX-h5 in Nicotiana benthamiana is sufficient to confer victorin sensitivity. Virus-induced gene silencing was used to characterize victorin-induced cell death in N. benthamiana. We determined that SGT1 is required for sensitivity and involved in LOV1 protein accumulation. We screened a normalized cDNA library and identified six genes that, when silenced, suppressed LOV1-mediated, victorin-induced cell death and cell death induced by expression of the closely related RPP8 resistance gene: a mitochondrial phosphate transporter, glycolate oxidase, glutamine synthetase, glyceraldehyde 3-phosphate dehydrogenase, and the P- and T-protein of the glycine decarboxylase complex. Silencing the latter four also inhibited cell death and disease resistance mediated by the PTO resistance gene. Together, these results provide evidence that the victorin response mediated by LOV1 is a defense response.
维多利亚枯萎病，由 Cochliobolus victoriae 引起，是一种最初在燕麦上描述并在拟南芥上重现的疾病。C. victoriae 的发病机制依赖于毒素 victorin 的产生。在燕麦中， victorin 敏感性由 Vb 基因赋予，该基因在遗传上与 Pc2 抗性基因不可分割。同时，在拟南芥中，敏感性由 LOCUS ORCHESTRATING VICTORIN EFFECTS1 (LOV1) 基因赋予。LOV1 编码一种核苷酸结合位点亮氨酸丰富重复蛋白，是一种通常与疾病抗性相关的蛋白质，而 LOV1“保护”防御硫氧还蛋白，TRX-h5。LOV1 和 TRX-h5 在 Nicotiana benthamiana 中的表达足以赋予 victorin 敏感性。利用病毒诱导的基因沉默来表征 Nicotiana benthamiana 中 victorin 诱导的细胞死亡。我们确定 SGT1 是敏感性所必需的，并且参与 LOV1 蛋白积累。我们筛选了一个归一化 cDNA 文库，并鉴定了六个基因，当它们沉默时，抑制了 LOV1 介导的、由 victorin 诱导的细胞死亡以及由密切相关的 RPP8 抗性基因表达诱导的细胞死亡：一种线粒体磷酸盐转运蛋白、乙醛酸氧化酶、谷氨酰胺合酶、甘油醛 3-磷酸脱氢酶和甘氨酸脱羧酶复合物的 P-和 T-蛋白。沉默后四个也抑制了由 PTO 抗性基因介导的细胞死亡和抗性。这些结果共同提供了证据，表明由 LOV1 介导的 victorin 反应是一种防御反应。
