Horvath B, Kondorosi E, John M, Schmidt J, Török I, Györgypal Z, Barabas I, Wieneke U, Schell J, Kondorosi A
Cell. 1986 Aug 1;46(3):335-43. doi: 10.1016/0092-8674(86)90654-9.
In R. meliloti we have identified four nodulation genes determining plant host-range specificity and have designated them hsnABC and D. The genes code for 9.7, 41.7, 26.7, and 28.6 kd proteins, respectively, and are organized into two transcriptional units. Mutations in these genes affect nodulation of their natural plant hosts Medicago sativa and Melilotus albus to different extents and hsnD mutants have an altered host-range. These Nod- mutations are not complementable by nodulation genes of other Rhizobium species such as R. leguminosarum. The hsn genes determine plant-specific infection through root hairs: hsnD is required for host-specific root hair curling and nodule initiation while the hsnABC genes control infection thread growth from the root hairs.
在苜蓿中华根瘤菌中，我们鉴定出了四个决定植物宿主范围特异性的结瘤基因，并将它们命名为hsnABC和D。这些基因分别编码9.7、41.7、26.7和28.6千道尔顿的蛋白质，并被组织成两个转录单元。这些基因中的突变对其天然植物宿主紫花苜蓿和白花草木樨的结瘤有不同程度的影响，hsnD突变体的宿主范围发生了改变。这些结瘤阴性突变不能被其他根瘤菌物种（如豌豆根瘤菌）的结瘤基因互补。hsn基因决定了通过根毛进行的植物特异性感染：hsnD是宿主特异性根毛卷曲和根瘤起始所必需的，而hsnABC基因则控制根毛中感染丝的生长。
