Isolation and characterization of NBS-LRR resistance gene candidates in rose.

RGAs have been isolated and characterized from many different plant species, and they are often located in genomic regions containing R genes. For the isolation and identification of RGAs, which were related to rose resistance to black pot, six pairs of degenerate primers were designed based on the transcriptome sequencing, and the NBS-LRR-RGAs were isolated and cloned from modern rose, Rosa laxa and Rosa rugosa ‘White’. 750 clones were selected and sequenced. Phylogenetic studies revealed that the sequenced rose RGAs clones showed a close relationship with R genes and these sequences were classified into ten clades, with non-TIR-NBS-RGAs and TIR-NBS-RGAs subclasses. The proportion of cloned non-TIR-NBS-RGAs was far greater than that of TIR-NBS-RGAs. The deduced amino acid sequences of RGAs all contained the whole conserved domains: P-Loop,kinase-2,kinase-3a and GLPL. The analysis of quantitative real-time PCR shows that the six RGAs from different clade participate in the reaction in different transcript levels and different time.