Cloning and Sequence Analysis of NBS Type Resistant Gene Analogs from Black Wax Gourd(Benincasa hispida)

According to the conserved domains of NBS typ e disease-resistant genes in most known plants,two degenerate primers were designed and synthesized.Nineteen RGAs named from DNB1 to DNA19 were obtained by PCR amplification of genome DNA from black wax gourd B98K variety.Sequences analysis and alignment results indicated that full-length of these RGAs varied from 249 nt to 252 nt,the deduced amino acids sequences contained typical conserved domains of NBS family,such as P-loop(GGVGKTT) and Kinase-2a(VLDDVW).The Gen Bank accession numbers were obtained(from KF776401 to KF776419).These RGAs showed great homologous differences with the similarity from 48.4% to 98.8% and with genetic divergence from 1.2 to 88.9 in nucleotide sequence level,while the amino acid sequence homology varied from 23.2% to 100.0%.These RGAs were all divided into non TIR-NBS-LRR group,which was consistent with the multiple-alignment of deduced amino acid sequences.The similarities varied from 24.7% to 99.0% compared with NBS RGAs of other known species.