Temperature and water stress impacts on growth and production of altertoxin-II by strains of Alternaria tenuissima from Argentinean wheat

Abstract

Alternaria tenuissima is commonly isolated from wheat in Argentina. The objective of this study was to examine the effects of temperature (15-34 °C) and water activity (0.98, 0.95 aw) on growth and temporal altertoxin II (ALTX-II) production by two strains over 14-21 days on a milled wheat agar. It was shown that growth occurred over the whole temperature range tested and was optimum at 25-30 °C and 0.98 aw, and 30 °C at 0.95 aw. The incubation time did not show any significant effect on ALTX-II accumulation. The optimum conditions for ALTX-II production were 0.98 aw and 30 °C for both strains. The strains also accumulated significant amounts of this toxin at 34 °C. This is the first study to evaluate the ecology of growth and production of ALTX-II by strains of A. tenuissima.