Pathogenicity and potential Toxigenicity of seed- borne Fusarium species on soybean and pea

The effect of 15 Fusarium species on seed germination and early plant development was examined in a laboratory study, together with the potential toxigenicity of selected isolates and the possibility of T-2 toxin production on soybean and pea grain. In germination tests, 33 out of 47 isolates of Fusarium chlamydosporum, F. pseudograminearum, F. sporotrichioides, F. crookwellense, F. verticillioides, F. equiseti, F. semitectum, F. solani, F. poae, F. sambucinum and F. compactum significantly reduced the number of normal soybean seedlings, while only six out of 48 isolates of F. sporotrichioides, F. semitectum and F. chlamydosporum significantly reduced the number of normal pea seedlings. When inoculated on plants grown in Hoagland's media, nearly all Fusarium isolates caused necrosis of soybean and pea root, but neither of them significantly reduced shoot and root dry mass of pea plants, or shoot dry mass of soybean plants. Amplification of tri5 and FUM1 genes, required for trichothecene and fumonisin biosynthesis, was carried out by PCR in 45 Fusarium isolates from soybean and 40 isolates from pea. Positive tri5 PCR reaction was recorded in 19 isolates of F. sporotrichioides, F. crookwellense, F. pseudograminearum, F. poae, F. sambucinum, F. culmorum, F. equiseti and F. chlamydosporum. Positive FUM1 PCR reaction was recorded in 35 out of 38 F. verticillioides and F. proliferatum isolates. The content of T-2 toxin produced by eight F. sporotrichioides isolates inoculated on autoclaved soybean, pea and barley grain ranged from 69.4 to 2595.5 μg/kg. No significant differences were determined between T-2 toxin production on soybean and barley grain, nor on pea and barley grain.