Antimicrobial activity of volatile organic compounds and their effect on lipid peroxidation and electrolyte loss in Colletotrichum gloeosporioides and Colletotrichum acutatum mycelia

Abstract

Anthracnose is an important plant disease and is the main disease affecting guava (Psidium guajava) post-harvest, leading to economic losses and limiting fruit export. Because of the indiscriminate use of fungicides, along with environmental and food safety concerns, alternative methods of disease control are warranted. The yeast Saccharomyces cerevisiae produces a mixture of volatile organic compounds (VOCs) that show in vitro antimicrobial activity against various phytopathogens, with the compounds 3-methyl-1-butanol (3M1B) and 2-methyl-1-butanol (2M1B) being primarily responsible for this activity. Considering the potential of using VOCs for controlling post-harvest anthracnose, this study aimed to evaluate the in vitro effect of 3M1B and 2M1B on the development of Colletotrichum gloeosporioides and C. acutatum, the causal agents of the disease in guava, and to elucidate the possible modes of action of these antimicrobials. The mycelial growth of the plant pathogens was inhibited similarly by 3M1B and 2M1B, and complete inhibition occurred at doses ≥1 μLmL -1 of air. Exposure of fungi to the VOCs increased the peroxidation levels of membrane lipids, indicating the occurrence of oxidative stress, in addition to increasing the non-selective permeability of the plasma membrane. Therefore, both 3M1B and 2M1B show potential to control C. gloeosporioides and C. acutatum.

Detection of Fungi and Oomycetes by Volatiles Using E-Nose and SPME-GC/MS Platforms

“…It has been proposed that these molecules could be waste products resulting from microbial metabolism, and released for detoxification purposes [17]. Previous studies have shown that volatiles are involved in antimicrobial activity [8,18]. They have highlighted VOC involvement in interactions with distant microbial colonies in the form of infochemical compounds, influencing development, gene expression, and behavior of the recipient microorganisms [4].…”

Antimicrobial Volatiles of the Insect Pathogen Metarhizium brunneum

“…Many non-EPF, such as Muscodor heveae, Xylaria sp., Daldinia cf concentrica and Saccharomyces cerevisiae, also produce antifungal VOCs that inhibit the growth of a wide range of phytopathogens, including Sclerotinia sclerotiorum, Colletotrichum gloeosporioides, Botrytis cinerea and Phyllosticta citricarpa [40][41][42][43][44][45][46]. Interestingly, one of the most inhibitory compounds produced by these fungi was methyl-1-butanol (isoamyl alcohol), which, in the current study, showed moderate inhibition of F. graminearum and B. cinerea and weak inhibition of P. ultimum.…”