TY - JOUR
T1 - Volatiles of antagonistic soil yeasts inhibit growth and aflatoxin production of Aspergillus flavus
AU - Natarajan, Subramani
AU - Balachandar, Dananjeyan
AU - Senthil, Natesan
AU - Velazhahan, Rethinasamy
AU - Paranidharan, Vaikuntavasan
N1 - Publisher Copyright:
© 2022 Elsevier GmbH
PY - 2022/10/1
Y1 - 2022/10/1
N2 - Minimizing Aspergillus flavus growth is an effective strategy to mitigate aflatoxin contamination in food and agricultural products. In the present investigation, we attempted to utilize soil-associated yeasts from the Western and Eastern Ghats of India against A. flavus to reduce aflatoxin contamination. Forty-five yeast isolates were screened against A. flavus using overlay and dual plate assays. Among them, 12 isolates effectively inhibited the growth of A. flavus. The 18S rDNA gene sequence analysis identified the twelve antagonistic isolates as belonging to Saccharomyces cerevisiae, Suhomyces xylopsoci, Pichia kudriavzevii, and Candida tropicalis. From the isolated yeasts, S. cerevisiae strains were selected for further evaluation based on the potential antagonistic activity. Volatiles of S. cerevisiae effectively suppressed the mycelial growth of A. flavus (P < 0.05) up to 92.1 % at 7 DAI. Scanning electron microscopic images of the fungus exposed to volatiles showed hyphal deformity and mycelial damage. Aflatoxin B
1 (AFB
1) production was drastically reduced up to 99.0 % in the volatile-exposed fungus compared to the control. The yeast strain YKK1 showed consistent Aspergillus flavus growth inhibition (80.7 %) and AFB
1 production (98.1 %) for 14 days. Gas chromatography-mass spectrophotometry analysis of the yeast volatiles revealed the presence of antimicrobial compounds, including 1-pentanol, 1-propanol, ethyl hexanol, ethanol, 2-methyl-1-butanol, ethyl acetate, dimethyl trisulfide, p-xylene, styrene, and 1,4-pentadiene. The evaluated compounds of yeast volatiles, including ethyl acetate, hexanal, 1-propanol, 1-heptanol, 1-butanol, and benzothiazole, inhibited the fungal growth and AFB
1 production of Aspergillus flavus when applied as pure chemicals. Benzothiazole at 5 mM was responsible for a high level of growth inhibition (23.6 %) and reduction of AFB
1 synthesis (93.5 %). Hence, volatile compounds produced by soil yeast strains could be a potential biocontrol mechanism against aflatoxin contamination.
AB - Minimizing Aspergillus flavus growth is an effective strategy to mitigate aflatoxin contamination in food and agricultural products. In the present investigation, we attempted to utilize soil-associated yeasts from the Western and Eastern Ghats of India against A. flavus to reduce aflatoxin contamination. Forty-five yeast isolates were screened against A. flavus using overlay and dual plate assays. Among them, 12 isolates effectively inhibited the growth of A. flavus. The 18S rDNA gene sequence analysis identified the twelve antagonistic isolates as belonging to Saccharomyces cerevisiae, Suhomyces xylopsoci, Pichia kudriavzevii, and Candida tropicalis. From the isolated yeasts, S. cerevisiae strains were selected for further evaluation based on the potential antagonistic activity. Volatiles of S. cerevisiae effectively suppressed the mycelial growth of A. flavus (P < 0.05) up to 92.1 % at 7 DAI. Scanning electron microscopic images of the fungus exposed to volatiles showed hyphal deformity and mycelial damage. Aflatoxin B
1 (AFB
1) production was drastically reduced up to 99.0 % in the volatile-exposed fungus compared to the control. The yeast strain YKK1 showed consistent Aspergillus flavus growth inhibition (80.7 %) and AFB
1 production (98.1 %) for 14 days. Gas chromatography-mass spectrophotometry analysis of the yeast volatiles revealed the presence of antimicrobial compounds, including 1-pentanol, 1-propanol, ethyl hexanol, ethanol, 2-methyl-1-butanol, ethyl acetate, dimethyl trisulfide, p-xylene, styrene, and 1,4-pentadiene. The evaluated compounds of yeast volatiles, including ethyl acetate, hexanal, 1-propanol, 1-heptanol, 1-butanol, and benzothiazole, inhibited the fungal growth and AFB
1 production of Aspergillus flavus when applied as pure chemicals. Benzothiazole at 5 mM was responsible for a high level of growth inhibition (23.6 %) and reduction of AFB
1 synthesis (93.5 %). Hence, volatile compounds produced by soil yeast strains could be a potential biocontrol mechanism against aflatoxin contamination.
KW - 1-heptanol
KW - 1-propanol
KW - Aflatoxin inhibition
KW - Aspergillus flavus
KW - Benzothiazole
KW - Saccharomyces cerevisiae
KW - VOCs
KW - Aflatoxin B1/genetics
KW - 1-Propanol/pharmacology
KW - Benzothiazoles/pharmacology
KW - Aflatoxins/pharmacology
KW - Soil
KW - 1-Butanol/pharmacology
UR - http://www.scopus.com/inward/record.url?scp=85135527582&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85135527582&partnerID=8YFLogxK
UR - https://www.mendeley.com/catalogue/862bd49a-dddf-36b7-b20a-3ab9eafadcdf/
U2 - 10.1016/j.micres.2022.127150
DO - 10.1016/j.micres.2022.127150
M3 - Article
C2 - 35940109
AN - SCOPUS:85135527582
SN - 0944-5013
VL - 263
JO - Microbiological Research
JF - Microbiological Research
M1 - 127150
ER -