Bertioli D J, Leal-Bertioli S C M, Lion M B, Santos V L, Pappas G, Cannon S B, Guimarães P M
Universidade Católica de Brasília, Pós Graduação Campus II, SGAN 916, DF CEP 70.790-160, Brasília, Brazil.
Mol Genet Genomics. 2003 Oct;270(1):34-45. doi: 10.1007/s00438-003-0893-4. Epub 2003 Aug 19.
Arachis hypogaea L., commonly known as the peanut or groundnut, is an important and widespread food legume. Because the crop has a narrow genetic base, genetic diversity in A. hypogaea is low and it lacks sources of resistance to many pests and diseases. In contrast, wild diploid Arachis species are genetically diverse and are rich sources of disease resistance genes. The majority of known plant disease resistance genes encode proteins with a nucleotide binding site domain (NBS). In this study, degenerate PCR primers designed to bind to DNA regions encoding conserved motifs within this domain were used to amplify NBS-encoding regions from Arachis spp. The Arachis spp. used were A. hypogaea var. Tatu and wild species that are known to be sources of disease resistance: A. cardenasii, A. duranensis, A. stenosperma and A. simpsonii. A total of 78 complete NBS-encoding regions were isolated, of which 63 had uninterrupted ORFs. Phylogenetic analysis of the Arachis NBS sequences derived in this study and other NBS sequences from Arabidopsis thaliana, Medicago trunculata, Glycine max, Lotus japonicus and Phaseolus vulgaris that are available in public databases This analysis indicates that most Arachis NBS sequences fall within legume-specific clades, some of which appear to have undergone extensive copy number expansions in the legumes. In addition, NBS motifs from A. thaliana and legumes were characterized. Differences in the TIR and non-TIR motifs were identified. The likely effect of these differences on the amplification of NBS-encoding sequences by PCR is discussed.
落花生（Arachis hypogaea L.），通常被称为花生或地豆，是一种重要且广泛种植的食用豆类。由于该作物的遗传基础狭窄，落花生的遗传多样性较低，并且缺乏对许多病虫害的抗性来源。相比之下，野生二倍体花生物种具有遗传多样性，是抗病基因的丰富来源。大多数已知的植物抗病基因编码具有核苷酸结合位点结构域（NBS）的蛋白质。在本研究中，设计用于结合该结构域内编码保守基序的DNA区域的简并PCR引物，被用于从花生属物种中扩增编码NBS的区域。所使用的花生属物种是落花生变种塔图（A. hypogaea var. Tatu）以及已知为抗病来源的野生种：卡氏花生（A. cardenasii）、杜兰花生（A. duranensis）、窄叶花生（A. stenosperma）和辛普森花生（A. simpsonii）。总共分离出78个完整的编码NBS的区域，其中63个具有不间断的开放阅读框。对本研究中获得的花生NBS序列与公共数据库中可获得的来自拟南芥（Arabidopsis thaliana）、蒺藜苜蓿（Medicago trunculata）、大豆（Glycine max）、百脉根（Lotus japonicus）和菜豆（Phaseolus vulgaris）的其他NBS序列进行了系统发育分析。该分析表明，大多数花生NBS序列属于豆科植物特有的进化枝，其中一些进化枝在豆科植物中似乎经历了广泛的拷贝数扩增。此外，还对拟南芥和豆科植物的NBS基序进行了表征。鉴定了TIR和非TIR基序的差异。讨论了这些差异对通过PCR扩增编码NBS序列可能产生的影响。
