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 (15-34o24 C) and water activity (aw, 0.98, 0.95) on growth 25 and temporal altertoxin-II (ALTX-II) production by two strains over 14-21 days on a milled 26 wheat agar. This showed that growth occurred over the whole temperature range tested and was optimum at 25-30oC and 0.98 aw, and 30o27 C at 0.95 aw. The incubation time did not show a 28 significant effect on ALTX-II accumulation. The optimum conditions for ALTX-II production 29 were 0.98 aw and 30°C for both strains. The strains also accumulated significant amounts of this 30 toxin at 34°C. This is the first study to evaluate the ecology of growth and production of ALTX31 II by strains of A. tenuissima.