|Kuldau, G - PLANT PATH/PENN STATE U|
|Leslie, J - PLANT PATH/KSU, MANHATTAN|
Submitted to: International IUPAC Symposium on Mycotoxins and Phycotoxins
Publication Type: Proceedings
Publication Acceptance Date: August 1, 2000
Publication Date: June 1, 2001
Interpretive Summary: Fusaric acid (5-butyl-picolinic acid) is produced by most Fusarium species and is implicated as a phytotoxin and mycotoxin. However, research suggest that fusaric acid, as well as other alkyl-picolinic acids (APAs) may have unique roles in Fusarium- intermediary metabolism, in symptomatic or asymptomatic Fusarium- related activities in plants, and also animal toxicities. In previous research, we reported fusaric acid was synergistic with fumonisin FB1 in the egg test and that contaminated feeds toxic to poultry contained fusaric acid, other analogues of this mycotoxin, and trace quantities of FB1. Present studies show F. thapsinum (the endophyte of sorghum) and F. moniliforme (the endophyte of corn) produce varying amounts of fusaric acid along with several other APAs, that frequently occur in Fusarium- contaminated agricultural products. To further understand the APAs' potential in food and feed while Fusaria are in planta, the above were measured in five strains of F. thapsinum, in F. moniliforme, and in F. semitectum on corn and synthetic media. Analysis of the media by gas chromatography-mass spectroscopy show these fungi produce various amounts and numerous analogues of fusaric acid. The abundance of these mycotoxins in cultures and field samples, along with our previous research, suggest further investigations are needed to define the APAs' role in Fusarium-plant interactions and animal toxicities.
Technical Abstract: FA (5-butyl-picolinic acid) is produced by most Fusarium species and is a phytotoxin and mycotoxin. Research suggest FA has a unique role in Fusarium-intermediary metabolism, in symptomatic or asymptomatic Fusarium-related activities in plants, and animal toxicity. Previously, we reported FA is synergistic with FB1 in the egg test and contaminated feeds toxic to poultry contained FA, 9,10-dehydro-FA (DHFA), 10-hydroxy-FA (10OHFA), with trace amounts of FB1. Present studies show F. thapsinum and F. moniliforme produce varying amounts of the above, with three other unknown APAs, that frequently occur in Fusarium- contaminated agricultural products. To further understand the APAs potential in food and feed while Fusaria are in planta, the above were measured in five strains of F. thapsinum (FB1 synthesis is nominal in these strains), in F. moniliforme (FmA), two FA-mutant strains (FmB; FmC), and F. semitectum. GC/MS analyses of the trimethyl-silyl-esters (TMS) of the three unknowns (i.e., APA1, APA2, APA3) suggest they are analogs of FA (i.e., amu fragmentation patterns similar to FATMS, DHFATMS, and 10OHFATMS2). In all F. thapsinum, FA was in minor conc. (range 27-663 micro-g/g corn), whereas 10OHFA was the major APA (2.5- 31xFA). In FmA: APA1>10OHFA>APA2>FA>DHFA>APA3 (micro-g/g corn). On corn and synthetic medium, FA in FmA>FmB>FmC and only FA was detected in FmC. The abundance of these APAs in culture and field samples warrant further research on their role in Fusarium-plant interactions.