Developments of functional markers for Fom-2-mediated fusarium wilt resistance based on single nucleotide polymorphism in melon (Cucumis melo L.)

Abstract

Three single nucleotide polymorphism (SNP) sites in which amino acids had changed were detected by sequence analysis within the leucine-rich repeat (LRR) region of the Fom-2 gene. Cleaved amplified polymorphic sequence (CAPS) and allele-specific PCR (AS-PCR) methods were employed to explore the SNP validation linked to fusarium wilt resistance in the F1 and F2 generations simultaneously. Homozygous- and heterozygous-resistant genotypes and homozygous-susceptible genotype could be clearly distinguished using the CAPS method, and three detected SNP sites were observed to be linked to fusarium wilt resistance, with a segregation ratio of 1:2:1 in the F2 generation. In addition, heterozygous-resistant and homozygous-susceptible genotypes could be clearly distinguished in the F1 generation using the AS-PCR method, showing a 3:1 segregation in terms of resistant and susceptible genotypes in the F2 generation. We therefore developed SNP-based functional markers (FMs) and identified some melon germplasm resistant to fusarium wilt by FM analysis within melon species. In conclusion, the SNP-based FMs originating from the SNP site of the Fom-2 LRR region were determined to be linked to fusarium wilt resistance and showed promise in the enhancement of breeding in melon.