Development of Molecular Markers for Detection of Acidovorax citrulli Strains Causing Bacterial Fruit Blotch Disease in Melon

Abstract

Acidovorax citrulli (A. citrulli) strains cause bacterial fruit blotch (BFB) in cucurbit crops and affect melon significantly. Numerous strains of the bacterium have been isolated from melon hosts globally. Strains that are aggressively virulent towards melon and diagnostic markers for detecting such strains are yet to be identified. Using a cross-inoculation assay, we demonstrated that two Korean strains of A. citrulli, NIHHS15-280 and KACC18782, are highly virulent towards melon but avirulent/mildly virulent to the other cucurbit crops. The whole genomes of three A. citrulli strains isolated from melon and three from watermelon were aligned, allowing the design of three primer sets (AcM13, AcM380, and AcM797) that are specific to melon host strains, from three pathogenesis-related genes. These primers successfully detected the target strain NIHHS15-280 in polymerase chain reaction (PCR) assays from a very low concentration of bacterial gDNA. They were also effective in detecting the target strains from artificially infected leaf, fruit, and seed washing suspensions, without requiring the extraction of bacterial DNA. This is the first report of PCR-based markers that offer reliable, sensitive, and rapid detection of strains of A. citrulli causing BFB in melon. These markers may also be useful in early disease detection in the field samples, in seed health tests, and for international quarantine purposes.

Characterization, identification and expression profiling of genome-wide R-genes in melon and their putative roles in bacterial fruit blotch resistance

“…Bacterial fruit blotch (BFB) is a devastating disease of melon caused by Acidovorax citrulli, an aerobic, mesophilic, gram-negative, rod-shaped seedborne bacterium belonging to the beta subdivision of the Proteobacteria [9]. BFB has been reported in many countries and poses a serious threat to melon, as well as other cucurbit crops including prickly paddy melon, citron melon, cucumber, pumpkin, squash, several types of gourds, and watermelon [10][11][12][13][14][15][16]. BFB causes watersoaked lesions to form on cotyledons and leaves, leading to collapse and death.…”

Characterization, Identification and Expression Profiling of Genome-Wide R-Genes in Melon and Their Putative Roles in Bacterial Fruit Blotch Resistance

“…BFB disease is caused by Acidovorax citrulli, an aerobic, mesophilic, gram-negative, rod-shaped seed-borne bacterium belonging to the beta subdivision of the Proteobacteria [9]. BFB has been reported in many countries and poses a serious threat to melon, as well as other cucurbit crops including prickly paddy melon, citron melon, cucumber, pumpkin, squash, several types of gourds, and watermelon [10][11][12][13][14][15][16]. BFB causes water-soaked lesions to form on cotyledons and leaves, leading to collapse and death.…”

Characterization, Identification and Expression Profiling of Genome-Wide R-Genes in Melon and Their Putative Roles in Bacterial Fruit Blotch Resistance

“…Bacterial fruit blotch (BFB) is a devastating disease of melon caused by Acidovorax citrulli, an aerobic, mesophilic, gram-negative, rod-shaped seed-borne bacterium belonging to the beta subdivision of the Proteobacteria [9]. BFB has been reported in many countries and poses a serious threat to melon, as well as other cucurbit crops including prickly paddy melon, citron melon, cucumber, pumpkin, squash, several types of gourds, and watermelon [10][11][12][13][14][15][16]. BFB causes water-soaked lesions to form on cotyledons and leaves, leading to collapse and death.…”