Nucleotide Divergence Analysis of IGS Region in Fusarium oxysporum and its formae speciales Based on the Sequence

Abstract

The intergenic spacer (IGS) sequence of Fusarium oxysporum have been reported to provide reliable information concerning intraspecific variation and phylogeny of fungal species. The eleven strains of Fusarium oxysporum and its formae speciales belonging to section Elegans were compared with sequencing analysis. The direct sequencing of partial IGS was carried out using PCR with primer NIGS1 (5′-CTTCGCCTCGATTTCCCCAA-3′)/NIGS2 (5′-TCGTCGCCGACAGTTTTCTG-3′) and internal primer NIGS3 (′5-TCGAGGATCGATTCGAGG-3′)/NIGS4 (5′-CCTCGAATCGATCCTCGA-3′). A single PCR product was found for each strain. The PCR fragments were sequenced and revealed a few within species polymorphisms at the sequence level. The size of partial IGS sequencing of F. oxysporum was divided into three groups; 526~527 bp including F. o. f. sp. chrysanthemi, cucumerinum, cyclaminis, lycopersici, and fragariae; 514~516 bp including F. o. f. sp. lilii, conglutinans, and raphani; 435 bp for F. o. f. sp. cucumerinum from Korea. Sequence analysis of PCR products showed that transitions were more frequent than transversions as well as the average numbers of substitution per site were range 0.41% to 3.54%.

Key Words:

• Fusarium oxysporum
• Intergenic spacer region (IGS)
• Nucleotide divergence sequencing