Fumonisin B1production byFusarium proliferatumstrains isolated fromAllium fistulosumplants and seeds in Japan

AIMS: To test the fumonisin B(1)-producing ability of Fusarium proliferatum strains isolated from Welsh onion (Allium fistulosum) plants and seeds of commercial cultivars in Japan and to examine the applicability of PCR-based assays to discriminate between fumonisin B(1)-producing and nonproducing isolates. METHODS AND RESULTS: Fumonisin B(1) levels in 20 Fusarium isolates obtained from Welsh onion plants and seeds of seven commercial cultivars were determined by HPLC. Thirteen of the 20 isolates produced fumonisin B(1). PCR assay with FUM1 gene-specific primers amplified a DNA fragment (700 bp) only from fumonisin-producing isolates. CONCLUSIONS: Fusarium proliferatum isolates that can produce fumonisin B(1) were often associated with wilted Welsh onion plants and seeds of some commercial cultivars. The PCR assay with FUM1 gene-specific primers has the potential to discriminate between fumonisin B(1)-producing and nonproducing isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: This study revealed that F. proliferatum producing fumonisin B(1) is associated with Welsh onion plants and that commercial cultivar seeds may be contaminated with the fungus. PCR amplification of FUM1 gene can be a useful tool for the rapid identification of fumonisin B(1)-producing F. proliferatum isolates.