Wilcox P L, Amerson H V, Kuhlman E G, Liu B H, O'Malley D M, Sederoff R R
Department of Forestry, North Carolina State University, Raleigh 37695, USA.
Proc Natl Acad Sci U S A. 1996 Apr 30;93(9):3859-64. doi: 10.1073/pnas.93.9.3859.
Genomic mapping has been used to identify a region of the host genome that determines resistance to fusiform rust disease in loblolly pine where no discrete, simply inherited resistance factors had been previously found by conventional genetic analysis over four decades. A resistance locus, behaving as a single dominant gene, was mapped by association with genetic markers, even though the disease phenotype deviated from the expected Mendelian ratio. The complexity of forest pathosystems and the limitations of genetic analysis, based solely on phenotype, had led to an assumption that effective long-term disease resistance in trees should be polygenic. However, our data show that effective long-term resistance can be obtained from a single qualitative resistance gene, despite the presence of virulence in the pathogen population. Therefore, disease resistance in this endemic coevolved forest pathosystem is not exclusively polygenic. Genomic mapping now provides a powerful tool for characterizing the genetic basis of host pathogen interactions in forest trees and other undomesticated, organisms, where conventional genetic analysis often is limited or not feasible.
基因组图谱已被用于确定火炬松宿主基因组中的一个区域，该区域决定了对梭形锈病的抗性，而在过去四十多年的传统遗传分析中，此前并未发现离散的、简单遗传的抗性因子。一个表现为单个显性基因的抗性位点通过与遗传标记的关联进行了定位，尽管疾病表型偏离了预期的孟德尔比率。森林病理系统的复杂性以及仅基于表型的遗传分析的局限性，导致人们假设树木中有效的长期抗病性应该是多基因的。然而，我们的数据表明，尽管病原菌群体中存在毒力，但从单个定性抗性基因中仍可获得有效的长期抗性。因此，在这种地方性共同进化的森林病理系统中，抗病性并非完全是多基因的。基因组图谱现在为表征林木和其他未驯化生物中宿主-病原体相互作用的遗传基础提供了一个强大的工具，而在这些生物中，传统遗传分析往往受到限制或不可行。
