棉 花 学 报      Cotton Science     2009，21(6)：462-467

Isolation，Characterization and Phylogenetic Analysis of the Resistance Gene Analogues (RGAs) in Upland Cotton ( Gossypium hirsutum L.) Zhongzhimian KV-1
ZHAO Lei，WANG Sheng-zheng，QI Fang-jun，ZHANG Wen-wei，JIAN Gui-liang^*
（Institute of Plant Protection，CAAS，the State Key Lab．for Biology of Plant Diseases and Insect Pest， Beijing 100193, China ）

Abstract：Most of known plant disease-resistance genes are featured with a nucleotide-binding site (NBS) and leucine-rich repeats (LRR)．A pair of degenerate primers and a pair of specific primer were designed based on the conserved NBS-LRR motifs among the known disease-resistance genes．The primers were used to amplify the disease-resistance gene analogues (RGAs) in upland cotton ( Gossypium hirsutum L.)．A PCR product about 500 bp was obtained．After cloning and sequences of the DNA fragments，10 NBS-LRR type RGAs were obtained．The deduced amino acid sequences of the DNA fragments contained the conserved motifs of NBS-LRR type RGAs，such as P-loop （kinase-1a），kinase-2，kinase -3a and GLPL domains．One of the RGAs is belonged to TIR-NBS-LRR type and the other nine are belonged to non-TIR-NBS-LRR type．When the TIR-NBS-LRR type RGA was compared with known disease-resistance gene such as N、L6、M，the percentage of amino acid homology ranged from 51% to 60%，while the other nine non-TIR-NBS-LRR type RGAs had 51%-60% homologous compared with known resistance gene such as RPS5、RPR1、Xa1 and so on．These RGAs may be further used as molecular marker for screening of candidate disease-resistance gene in cotton．
Key words：cotton；resistance gene analogues；NBS-LRR     [Full Text, 3999KB]