Zhu Hongyan, Cannon Steven B, Young Nevin D, Cook Douglas R
Department of Plant Pathology, University of California, Davis 95616, USA.
Mol Plant Microbe Interact. 2002 Jun;15(6):529-39. doi: 10.1094/MPMI.2002.15.6.529.
Sequences homologous to the nucleotide binding site (NBS) domain of NBS-leucine-rich repeat (LRR) resistance genes were retrieved from the model legume M. truncatula through several methods. Phylogenetic analysis classified these sequences into TIR (toll and interleukin-1 receptor) and non-TIR NBS subfamilies and further subclassified them into several well-defined clades within each subfamily. Comparison of M. truncatula NBS sequences with those from several closely related legumes, including members of the tribes Trifoleae, Viceae, and Phaseoleae, reveals that most clades contain sequences from multiple legume species. Moreover, sequences from species within the closely related Trifoleae and Viceae tribes (e.g., Medicago and Pisum spp.) tended to be cophyletic and distinct from sequences of Phaseoleae species (e.g., soybean and bean). These results suggest that the origin of major clades within the NBS-LRR family predate radiation of these Papilionoid legumes, while continued diversification of these sequences mirrors speciation within this legume subfamily. Detailed genetic and physical mapping of both TIR and non-TIR NBS sequences in M. truncatula reveals that most NBS sequences are organized into clusters, and few, if any, clusters contain both TIR and non-TIR sequences. Examples were found, however, of physical clusters that contain sequences from distinct phylogenetic clades within the TIR or non-TIR subfamilies. Comparative mapping reveals several blocks of resistance gene loci that are syntenic between M. truncatula and soybean and between M. truncatula and pea.
通过多种方法从模式豆科植物蒺藜苜蓿中检索到与NBS-富含亮氨酸重复序列（LRR）抗性基因的核苷酸结合位点（NBS）结构域同源的序列。系统发育分析将这些序列分为TIR（Toll和白细胞介素-1受体）和非TIR NBS亚家族，并在每个亚家族内进一步细分为几个明确的进化枝。将蒺藜苜蓿NBS序列与几种近缘豆科植物（包括三叶草族、野豌豆族和菜豆族的成员）的序列进行比较，发现大多数进化枝包含来自多个豆科物种的序列。此外，近缘三叶草族和野豌豆族内物种（如苜蓿属和豌豆属物种）的序列往往是共系的，且与菜豆族物种（如大豆和菜豆）的序列不同。这些结果表明，NBS-LRR家族内主要进化枝的起源早于这些蝶形花亚科豆科植物的辐射分化，而这些序列的持续多样化反映了该豆科亚科内的物种形成。对蒺藜苜蓿中TIR和非TIR NBS序列进行详细的遗传和物理图谱分析发现，大多数NBS序列被组织成簇，很少有簇同时包含TIR和非TIR序列。然而，发现了一些物理簇的例子，这些簇包含来自TIR或非TIR亚家族内不同系统发育进化枝的序列。比较图谱分析揭示了蒺藜苜蓿与大豆之间以及蒺藜苜蓿与豌豆之间几个抗性基因位点的共线性区域。
