Department of Molecular Biology, Microbiology and Biochemistry, Southern Illinois University at Carbondale, Carbondale, IL 62901, USA.
Theor Appl Genet. 2012 Apr;124(6):1027-39. doi: 10.1007/s00122-011-1766-6. Epub 2011 Dec 27.
Host resistance to "yellow dwarf" or "moonlight" disease cause by any population (Hg type) of Heterodera glycines I., the soybean cyst nematode (SCN), requires a functional allele at rhg1. The host resistance encoded appears to mimic an apoptotic response in the giant cells formed at the nematode feeding site about 24-48 h after nematode feeding commences. Little is known about how the host response to infection is mediated but a linked set of 3 genes has been identified within the rhg1 locus. This study aimed to identify the role of the genes within the locus that includes a receptor-like kinase (RLK), a laccase and an ion antiporter. Used were near isogeneic lines (NILs) that contrasted at their rhg1 alleles, gene-based markers, and a new Hg type 0 and new recombination events. A syntenic gene cluster on Lg B1 was found. The effectiveness of SNP probes from the RLK for distinguishing homolog sequence variants on LgB1 from alleles at the rhg1 locus on LgG was shown. The resistant allele of the rhg1 locus was shown to be dominant in NILs. None of the recombination events were within the cluster of the three candidate genes. Finally, rhg1 was shown to reduce the plant root development. A model for rhg1 as a dominant multi-gene resistance locus based on the developmental control was inferred.
大豆胞囊线虫（SCN）的异皮线虫属第 Hg 型种群引起的“黄矮病”或“月光病”的宿主抗性需要 rhg1 功能等位基因。编码的宿主抗性似乎模拟了线虫开始取食后 24-48 小时线虫取食部位形成的巨型细胞中的细胞凋亡反应。目前尚不清楚宿主对感染的反应是如何介导的，但在 rhg1 基因座内已经确定了一组相关的 3 个基因。本研究旨在确定包括受体样激酶 (RLK)、漆酶和离子反转运蛋白在内的基因座内基因的作用。使用的是在 rhg1 等位基因上存在差异的近等基因系 (NIL)、基于基因的标记以及新的 Hg 型 0 和新的重组事件。在 Lg B1 上发现了一个同源基因簇。结果表明，RLK 的 SNP 探针可有效区分 LgB1 上与 LgG 上 rhg1 基因座等位基因同源的序列变体。rhg1 基因座的抗性等位基因在 NILs 中表现为显性。没有任何重组事件发生在这三个候选基因的簇内。最后，rhg1 被证明会减少植物根系的发育。基于发育控制，推断出 rhg1 作为显性多基因抗性基因座的模型。
