Impact of cycling temperatures on Fusarium verticillioides and F. graminearum growth and mycotoxins production in soybean.

GARCÍA, D.; BARROS G.; CHULZE, S.; RAMOS A.; SANCHIS V.; MARÍN S.

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

JOHN WILEY & SONS LTD

Lugar: Londres; Año: 2012 vol. 92 p. 2952 - 2959

0022-5142

Fusarium graminearum and F. verticillioides are two very important mycotoxigenic species as they cause diverse diseases in crops. The effect of constant and cycling temperatures on growth and mycotoxin production of these species were studied on soybean based medium and on irradiated soya beans. Fusarium graminearum grew better when was incubated at 15, 20 and 15-20 ºC (isothermal or cycling temperature). With respect to F. verticillioides, grew better at 25 ºC in culture medium and at 15-20 ºC, 15-25 ºC on soybean seeds. Besides, mycotoxins production was higher under isothermal temperatures compared to cycling temperatures. Maximum levels of zearalenone (ZEA) and deoxynivalenol (DON) (39.25 and 1040.4 µg/g, respectively) were detected on soya beans after 15 days of incubation. However, optimum temperature for mycotoxin production was different for each toxin: 15 ºC for ZEA and 20 ºC for DON. On the other side, F. verticillioides only produced fumonisin B1 (FB1) on culture medium, and the maximum level (7.38 µg/g) was found at 15 ºC after 7 days of incubation. Finally, growth and mycotoxin production under cycling temperatures were predicted with the sum of 12 hours under constant condition. In general, observed values were different from calculated (p<0.05) for both species and substrate medium. Therefore, care should be taken when data are extrapolated to real field conditions from constant growth conditions.