Powdery mildew resistance gene ( Pm- AN) located in a segregation distortion region of melon LGV.

Powdery mildew is one of the most important melon pathogens all over the world. So far, many genes conferring resistance to powdery mildew of melon have been described, but few of these have been finely mapped or cloned. Two F populations derived from Ano2 × Hami413 and Ano2 × Queen were used to map the powdery mildew resistance gene by methods of Bulked Segregation Analysis (BSA), comparative genomics and Resistance Gene Analogues (RGA) mapping. It was found that the resistance to powdery mildew in Ano2 was conferred by a dominant gene, and the gene was named Pm- AN. The genetic analysis revealed that Pm- AN located between two codominant markers RPW and MRGH63B in linkage groupV. The genetic distances between Pm- AN and these two markers were 1.4-1.8 and 1.6-2 cM. No recombination was found between Pm- AN and markers ME/E1, SRAP23. Pm- AN was located in a RGA-rich region and cosegregated with the RGA marker MRGH5 and the resistance gene Vat. Synteny analysis showed that markers in this region were collinear between melon and cucumber. Segregation distortion was found in this region using both Ano2 × Hami413 and Ano2 × Queen F populations, and the distortion was more distinct in Ano2 × Hami413 F population. The center of segregation distortion was located in the RGA rich region harboring Pm- AN. [ABSTRACT FROM AUTHOR]