Isolation and characterization of resistance gene candidates from a genomic TAC library of a wheat- Thinopyrum intermedium translocation line.

摘要

Nine resistance gene analogs (RGAs) of Tlx. intermedium were obtained by PCR with degenerate primers to the conversed motifs in resistance genes and sequence analysis. Using the RGAs as probes, the results of RFLP analysis indicated that the NBS-RGA TirgaZl was associated with Bdv2 gene. Based on the sequence of TirgaZl, a pair of new specific primers of TZ1U and TZ1L were designed, synthesized and used to screen the genomic DNA TAC library of HW642. By 3 rounds of screening, 4 positive TAC clones ofTl, T2, T3 and T4 were isolated, of which Tl, T2 and T3 contained the insert about 23kb, and T4 belonged to another with the insert about 25kb. Results indicated that the clones of Tl and T4 share common sequences and different sequences, contain NBS-RGA TirgaZl, and derived from the Th. intermedium chromosome 7XL. Sequence analysis showed that the clones of Tl and T4 harbored NBS conversed domains, and could be used as BYDV resistance candidates.