西瓜斑枯病病原菌分离鉴定及特异性引物设计OA

Watermelon spot disease,one of the important diseases in greenhouse watermelon cultivation,has been a major constraint on the effective implementation of green control measures due to unclear pathogen identification and lack of early diagnostic techniques.From 2022 to 2025,this study focused on the primary greenhouse watermelon production ar-eas in Shandong,China.Typical watermelon spot samples were systematically collected,and the pathogenic fungus was isolated through tissue separation,further verified for pathogenicity using Koch's postulates,and identified based on mor-phological characteristics and multilocus phylogenetic analysis.The pathogen was determined to be Cercospora citrulli-na.Specific primers(Cer-F/Cer-R)were designed based on conserved regions of the pathogen's genome.After optimiz-ing reaction conditions,a specific 301 bp fragment was successfully amplified at an annealing temperature≥69.5℃,with the limit of detection of 100 pg·μL-1.Specificity assays demonstrated no cross-reaction with seven common watermelon pathogens,including Alternaria spp.,Fusarium spp.,and Stagonosporopsis spp.,Colletotrichum spp.,confirming high specificity.This study confirms C.citrullina was the causal agent of watermelon spot disease in Shandong and establishes a highly specific and sensitive PCR-based detection method,providing technical support for early monitoring and green management of the disease.