The impact of the postharvest environment on the viability and virulence of decay fungi

ABSTRACT

Postharvest decay of fruits, vegetables, and grains by fungal pathogens causes significant economic losses. Infected produce presents a potential health risk since some decay fungi produce mycotoxins that are hazardous to human health. Infections are the result of the interplay between host resistance and pathogen virulence. Both of these processes, however, are significantly impacted by environmental factors, such as temperature, UV, oxidative stress, and water activity. In the present review, the impact of various physical postharvest treatments (e.g., heat and UV) on the viability and virulence of postharvest pathogens is reviewed and discussed. Oxidative injury, protein impairment, and cell wall degradation have all been proposed as the mechanisms by which these abiotic stresses reduce fungal viability and pathogenicity. The response of decay fungi to pH and the ability of pathogens to modulate the pH of the host environment also affect pathogenicity. The effects of the manipulation of the postharvest environment by ethylene, natural edible coatings, and controlled atmosphere storage on fungal viability are also discussed. Lastly, avenues of future research are proposed.

KEYWORDS:

• Heat stress
• manipulated environment
• oxidative stress
• pathogen viability
• pH
• stress response

Acknowledgments

We greatly appreciate the many contributions published on the subject of this review, and apologize to the investigators whose specific studies were not be cited due to space limitations but whose work framed the issues and ideas that are discussed.

Funding

This work was supported by National Natural Science Foundation of China (31501688 and 31670688), the project of Chongqing Education Commission (KJ1711275), the project sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry to Yuan Sui, and the project of Chongqing Science & Technology Commission (cstc2016jcyjA1769).