Abstract The nucleotide binding site (NBS) domain sequences were isolated from genomic DNA in black bamboo, using the degenerate primer designed according to the conserved motifs of the NBS resistance gene. The expected size of the PCR product was about 700 bp. Among 55 positive clones, the amino acid sequence alignment identified 33 black bamboo resistance gene analogs (RGAs) that contain the NBS conserved motifs. All of the 33 RGAs ORFs were constructed in an NJ (Neighbor-joining) tree, and divided into 10 groups. This analysis demonstrated the diversity of the NBS class RGA in black bamboo. The maximum likelihood estimates of various evolutionary models were analyzed; the result showed that 2 groups with a total of 10 sequences and 12 sites demonstrated statistically significant positive selection. Most of the positive selected sites were not located in the NBS conserved motifs. Two groups of gene conversion events had been discovered, which provide a material basis and research direction in isolating black bamboo R genes.

中文翻译：

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黑竹（Phyllostachys nigra）NBS类抗性基因类似物的克隆及分子进化分析

摘要 使用根据NBS抗性基因保守基序设计的简并引物，从黑竹基因组DNA中分离出核苷酸结合位点（NBS）结构域序列。PCR 产物的预期大小约为 700 bp。在 55 个阳性克隆中，氨基酸序列比对鉴定了 33 个包含 NBS 保守基序的黑竹抗性基因类似物 (RGA)。所有 33 个 RGAs ORF 均构建在 NJ（邻居加入）树中，并分为 10 组。该分析证明了黑竹中 NBS 类 RGA 的多样性。分析了各种进化模型的最大似然估计；结果表明，共有10个序列和12个位点的2组表现出统计学上显着的阳性选择。大多数阳性选择位点不位于 NBS 保守基序中。发现了两组基因转化事件，为分离黑竹R基因提供了物质基础和研究方向。