Meeley R. B., Johal G. S., Briggs S. P., Walton J. D.
Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824-1312.
Plant Cell. 1992 Jan;4(1):71-77. doi: 10.1105/tpc.4.1.71.
In maize, major resistance to the pathogenic fungus Cochliobolus (Helminthosporium) carbonum race 1 is determined by the dominant allele of the nuclear locus hm. The interaction between C. carbonum race 1 and maize is mediated by a pathogen-produced, low molecular weight compound called HC-toxin. We recently described an enzyme from maize, called HC-toxin reductase, that inactivates HC-toxin by pyridine nucleotide-dependent reduction of an essential carbonyl group. We now report that this enzyme activity is detectable only in extracts of maize that are resistant to C. carbonum race 1 (genotype Hm/Hm or Hm/hm). In several genetic analyses, in vitro HC-toxin reductase activity was without exception associated with resistance to C. carbonum race 1. The results indicate that detoxification of HC-toxin is the biochemical basis of Hm-specific resistance of maize to infection by C. carbonum race 1.
在玉米中，对致病真菌玉米小斑病菌1号生理小种（Cochliobolus (Helminthosporium) carbonum race 1）的主要抗性由细胞核基因座hm的显性等位基因决定。玉米小斑病菌1号生理小种与玉米之间的相互作用是由病原菌产生的一种名为HC毒素的低分子量化合物介导的。我们最近描述了一种来自玉米的酶，称为HC毒素还原酶，它通过依赖吡啶核苷酸还原一个必需的羰基来使HC毒素失活。我们现在报告，这种酶活性仅在对玉米小斑病菌1号生理小种具有抗性的玉米提取物中可检测到（基因型为Hm/Hm或Hm/hm）。在几项遗传分析中，体外HC毒素还原酶活性无一例外地与对玉米小斑病菌1号生理小种的抗性相关。结果表明，HC毒素的解毒作用是玉米对玉米小斑病菌1号生理小种感染产生Hm特异性抗性的生化基础。
