Sequence Analysis Of NBS Type Resistance Gene Analongs In Secale L.

Secale L., the tertiary gene pool of Triticum, has a lot of resistance genes in its R genome. Thus, it has great potential to be an important genetic resources to increase the genetic variations and introduce desirable genes for wheat improvement. Up to now, no disease resistance-relative genes have been cloned from Secale L. In this study, the degenerate primers were designed based on the NBS-LRR resistance gene structure of the amino domains, and some RGAs were isolated form Secale. The results were described as follows:1. According to the conserved domains NBS-LRR of the cloned R gene, 10 degenerate primers were designed, and used to amplify the RGAs from the genomic DNA of five Secale species. A total of 45 RGAs were obtained, among which 16 RGAs had the uninterrupted open reading frames(ORFs).2 .The analyses of the 16 RGAs structures and NBS domains indicated that all the RGAs from Secale contained the motifs of P-loop, Kin-2 and "GLPL". Comparison of the putative amino acid sequences of these 16 RGAs with known genes showed that these RGAs has homologous with flax L6, Arabidopsis RPP5, Arabidopsis RPM1 and Triticum PM3A.3. The 16 RGAs had the conserved domains of NB-ARC, among which RGA1, RGA2, RAG4 and RGA5 had the 86%-94% homologous with resistance protein from Triticum, while RGA3, RGA4 and RGA14 had the 77%, 78% and 84% homologous with resistance protein fom Hordem vulgare, respectively.RGA11 and RGA14 had 94% and 98% homologous with resistance protein from Lolium perenne.These results could provide some theoretic and experimental data for the isolation of related resistance genes from Secale, and the development of molecular markers for MAS. And also, it would give some information for the origin and evolution of NBS-LRR type R gene.