Mycoflora and fumonisin mycotoxins associated with cowpea [Vigna unguiculata (L.) Walp] seeds.
Cowpea seed samples from South Africa and Benin were analyzed for seed mycoflora. Fusariumspecies detected were F. equiseti, F. chlamydosporum, F. graminearum, F. proliferatum, F. sambucinum, F. semitectum, and F. subglutinans. Cowpea seed from South Africa and Benin and F. proliferatum isolates from Benin, inoculated onto maize patty medium, were analyzed for fumonisin production. Samples were extracted with methanol/water and cleaned up on strong anion exchange solid phase extraction cartridges. HPLC with precolumn derivatization using o-phthaldialdehyde was used for the detection and quantification of fumonisins. Cowpea cultivars from South Africa showed the presence of fumonisin B(1) at concentrations ranging between 0.12 and 0.61 microg/g, whereas those from Benin showed no fumonisins. This is believed to be the first report of the natural occurrence of FB(1) on cowpea seed. Fumonisin B(1), B(2), and B(3) were produced by all F. proliferatum isolates. Total fumonisin concentrations were between 0.8 and 25.30 microg/g, and the highest level of FB(1) detected was 16.86 microg/g.
Kritzinger
Quenton
Q
Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, 0002 South Africa. qkritz@postino.up.ac.za
Aveling
Theresa A S
TA
Marasas
Walter F O
WF
Rheeder
John P
JP
Van Der Westhuizen
Liana
L
Shephard
Gordon S
GS
D001230:Aspergillus / Q000302:isolation & purification; D037341:Fumonisins / Q000032:analysis*; D005670:Fusarium / Q000302:isolation & purification / Q000378:metabolism; D010407:Penicillium / Q000302:isolation & purification; D027805:Phaseolus / Q000737:chemistry* / Q000382:microbiology*; D012639:Seeds / Q000737:chemistry* / Q000382:microbiology*
D037341:Fumonisins; C056934:fumonisin B2; C073063:fumonisin B3; C056933:fumonisin B1