Development of SCAR from SRAP molecular markers closely linked to powdery mildew-resistant genes in bitter melon (Momordica charantia L.).

【Objective】Molecular markers closely linked to powdery mildew resistant genes in bitter melon(Momordica charantia L.) were obtained to provide basis on accelerating the development of new powdery mildew resistant cultivars.【Method】The plants from F2generations were created through the hybridization of highly powdery mildew-sensitive and cultivated bitter melon MC1-2 as female parent with strongly powdery mildew- resistant and wild bitter melon MC18 as male parent. After identification powdery mildew resistance abilities with their parents, the near-isogenic DNA pools from F2population plants were classified on the basis of bulked segregation analysis(BSA) method. Polymorphic amplified fragments were screened from near-isogenic DNA pools by sequence-related amplified polymorphism(SRAP) technique.The differential fragments only belonging to powdery mildew-resistant near-isogenic pool and paternal plant were retrieved, sequenced, blasted, and changed into SCAR marker. The correlations of sequence characterized amplified region(SCAR) molecular marker with powdery mildew-resistant abilities were analyzed based on DNA of the known disease-resistant or-sensitive plants. 【Result】Five pairs of SRAP primers in 1188 had stable and positive differential fragments,of which ME20EM5 primer combination not only got a differential fragment with 332 bp sharing comparatively high similarity with gene encoded grape antibody protein(disease-resistant gene), but also changed into 320 bp SCAR molecular marker significantly correlated with powdery mildew resistance. 【Conclusion】SCAR molecular marker screened could be used to develop powdery mildew-resistant bitter melon using marker-assisted selection.