Johal G S, Briggs S P
Department of Biotechnology Research, Pioneer Hi-Bred International, Inc., Johnston, IA 50131.
Science. 1992 Nov 6;258(5084):985-7. doi: 10.1126/science.1359642.
The HM1 gene in maize controls both race-specific resistance to the fungus Cochliobolus carbonum race 1 and expression of the NADPH (reduced form of nicotinamide adenine dinucleotide phosphate)-dependent HC toxin reductase (HCTR), which inactivates HC toxin, a cyclic tetrapeptide produced by the fungus to permit infection. Several HM1 alleles were generated and cloned by transposon-induced mutagenesis. The sequence of wild-type HM1 shares homology with dihydroflavonol-4-reductase genes from maize, petunia, and snap-dragon. Sequence homology is greatest in the beta alpha beta-dinucleotide binding fold that is conserved among NADPH- and NADH (reduced form of nicotinamide adenine dinucleotide)-dependent reductases and dehydrogenases. This indicates that HM1 encodes HCTR.
玉米中的HM1基因既控制对真菌玉米炭疽菌1号生理小种的小种特异性抗性，又控制NADPH（还原型烟酰胺腺嘌呤二核苷酸磷酸）依赖性HC毒素还原酶（HCTR）的表达，该酶可使HC毒素失活，HC毒素是真菌产生的一种环状四肽，可促进感染。通过转座子诱导诱变产生并克隆了几个HM1等位基因。野生型HM1的序列与来自玉米、矮牵牛和金鱼草的二氢黄酮醇-4-还原酶基因具有同源性。在β-α-β二核苷酸结合折叠区序列同源性最高，该区域在NADPH和NADH（还原型烟酰胺腺嘌呤二核苷酸）依赖性还原酶和脱氢酶中保守。这表明HM1编码HCTR。
