Interactive Effects of Abiotic Factors on the Ecophysiology Characteristics of Aspergillus flavus Under Future Climate Conditions

Climate change could affect the growth and colonization of Aspergillus flavus (A. flavus) in maize, increasing the risk of mycotoxins in aflatoxins (AFs) and cyclopiazonic acid (CPA). However, changes in ecophysiological characteristics of A. flavus under future climate scenarios remain unclear, particularly under alternating temperatures resulting from day and night variations. This study aims to explore the interactive effects of alternating temperatures (28/20 o C and 33/25 o C) under the photoperiod with 13 h light/11h darkness, CO 2 (400 ppm and 1000 ppm), and different water activities (0.93aw, 0.95aw and 0.99aw). The growth rate, lag phase, conidia production, oxidative stress indicators and related mycotoxins (AFs and CPA) of A. flavus were analyzed under a combination of different climatic factors in maize flour agar (MFA) and potato dextrose agar (PDA) medium. The results indicate that water activity is the primary factor regulating A. flavus growth, conidia production, and mycotoxin production. Its single-factor effects and interactions with other factors exert a highly significant influence on all indicators (p<0.001). Elevated alternating temperatures promote the growth of A. flavus . The impact of CO 2 is relatively limited, with significant effects observed only on conidia and CPA. The interaction between alternating temperature, water activity, and CO 2 concentration have an effect on growth and mycotoxin production in A. flavus . However, mycotoxin production does not fully correlate with gene expression. These findings provide valuable baseline data on the interactions between temperature, water activity, and CO 2 concentration in relation to A. flavus growth and mycotoxin production.