Development of PCR-based markers for powdery mildew resistance gene Pm4a of wheat.

摘要

Ma et al (1994) reported a co-segregating RFLP marker Xbcdl231 for Pm4a. To simplify the genotyping process for Pm4a-carried lines, the conversion of BCD 1231 to a STS marker was performed. The STS primers designed based on the end sequences of BCD 1231 amplified a 1584 bp fragment in the Pm4a isogenic lines. Polymorphism of the amplified products was discovered after four-cutter enzymes Hae III and Msp I were applied. A F2 population of 88 plants was surveyed with this STS marker and the polymorphism showed co-segregation with the resistance, consistent with the result of RFLP genotyping with BCD 1231. To design Pm4a-specific PCR markers, the -1.5 kb products from the susceptible parent were sequenced and compared with the one linked to Pm4a. A newPCR marker, based on the sequence in an intron region covered in the -1.5 kb sequence, was identified, which detects a product of 470 bp only in the Pm4a-carried lines. These STS markers is useful for marker-assisted selection (MAS) of Pm4a.