Effect of different temperatures and CO2 levels on Alternaria toxins produced on cultivated rocket, cabbage and cauliflower

Abstract

Over the last 100 years, the global mean temperature has increased and has influenced several key factors that affect the occurrence and severity of fungal diseases. The effect of an increase in CO2 concentration and temperature on disease caused by four Alternaria strains and their mycotoxin production on cultivated rocket, cabbage and cauliflower plants has been investigated in this study. Six different temperature and CO2 combinations were considered: (1) 400-450 ppm CO2, 14-18 °C; (2) 800-850 ppm CO2, 14-18 °C; (3) 400-450 ppm CO2, 18-22 °C; (4) 800-850 ppm CO2, 18-22 °C; (5) 400-450 ppm CO2, 22-26 °C; and (6) 800-850 ppm CO2, 22-26 °C. Higher levels of CO2 and temperature have been found to significantly influence the disease index of the infected plants. In fact, the disease index was significantly increased at 22-26 °C and 800-850 ppm of CO2 for all of the host plants. Tenuazonic acid (TeA), alternariol, alternariol monomethyl ether and tentoxin were analysed for each climate condition using HPLC-MS/MS, and disease severity was evaluated. Higher temperature influences environmental conditions and different factors involved in plant-pathogen interaction. Temperature was the main factor involved in disease severity, while host plants and strains were found to be the factors that had the most influence on the variation of the production of mycotoxins. A large variability in the production of mycotoxins among the different host plants was observed, but TeA was always the most frequently produced mycotoxin.