Considerable quantities of fruit are lost during pre- and post-harvest stages due to mould spoilage. The aim of this study was to evaluate the antagonistic effect of selected yeasts against spoilage mould Botrytis cinerea , Penicillium expansum and Alternaria alstroemeriae . One hundred and...

Apples and strawberries hold significant commercial and nutritional value but face pre- and post-harvest spoilage due to infections by Botrytis cinerea. While spoilage is conventionally managed using synthetic chemicals, there is a growing interest in utilising yeasts as biological control agents. This study aimed to assess the antifungal potential of non-Saccharomyces yeasts Suhomyces pyralidae, Meyerozyma guilliermondii, Pichia kluyveri, Zygoascus hellenicus, and Aureobasidium melanogenum against three B. cinerea strains (B05.10, IWBT-FF1, and PPRI 30807) on agar plates and in post-harvest trials on apples and strawberries. Aureobasidium melanogenum exhibited a broad range of extracellular enzyme production and inhibition rates of 55%, 52%, and 40% against the strains. In volatile organic compound (VOC) assays, P. kluyveri and S. pyralidae achieved 79% and 56% inhibition, respectively, with VOCs like isobutanol, isoamyl alcohol, 2-phenylethanol, isoamyl acetate, and 2-phenethyl acetate identified. In post-harvest trials, S. pyralidae was most effective on apples, with inhibition rates up to of 64%. The commercial fungicide Captan and S. pyralidae and P. kluyveri achieved 100% inhibition against the B. cinerea strains B05.10 and IWBT-FF1 on strawberries. These findings highlight the potential of the selected yeast species as biological control agents against B. cinerea, warranting further research into their application in commercial fruit protection.

Fruit producers and exporters around the world are grappling with challenges related to post-harvest fruit decay, particularly in fruits such as apples and oranges destined for export, leading to waste and financial losses. The filamentous fungi, specifically Penicillium species, are the primary post-harvest pathogens affecting apples and oranges. This study evaluated the use of five non -Saccharomyces yeast species ( Suhomyces pyralidae, Meyerozyma guilliermondii, Pichia kluyveri , Zygoascus helenicus and Aureobasidium melanogenum ) as biocontrol agents against Penicillium expansum , P. digitatum and P. italicum . The yeasts were screened for their inhibitory effects using radial inhibition and mouth-to-mouth assays on agar plates and post-harvest trials on apples and oranges. Aureobasidium melanogenum exhibited the most significant growth inhibition in the radial inhibition assay, achieving 60%, 100% and 70% inhibition against P. expansum , P. digitatum and P. italicum, respectively. In the volatile compound assay, Pi. kluyveri achieved complete (100%) inhibition of P. expansum, P. digitatum and P. italicum. Seven volatile compounds were identified, isobutanol, 2-phenylethanol, isoamyl acetate, isoamyl alcohol and 2-phenethyl acetate associated with the inhibition of P. expansum . In post-harvest trials, the yeast treatments displayed limited inhibition activity on apples ( ca. 15%). However, on oranges, M. guilliermondii demonstrated substantial inhibition, achieving 72% and 77% inhibition against P. digitatum and P. italicum, respectively . These findings suggest that the selected yeast species have potential as biological control agents against P. expansum, P. digitatum and P. italicum , although further research is required to fully understand and optimise their application.

Ten phyllospheric yeast strains were studied for their potential as biocontrol agents against fruit spoilage mould. The efficacy of these yeasts against Botrytis cinerea and Fusarium fujikuroi was assessed using dual-culture, mouth-to-mouth, radial growth inhibition and post-harvest fruit assays. Additionally, their capacity for producing hydrolytic enzymes was examined. Results from the ten yeasts revealed dual culture antagonism ranging from 41% to 63% against B. cinerea and 23% to 48% against F. fujikuroi, along with radial inhibition ranging from 70% to 100% and 47% to 100%, respectively. Additionally, in vitro inhibition through the production of volatile organic compounds (VOCs) varied from 2% to 46% against B. cinerea and 6% to 64% against F. fujikuroi. Overall, Aureobasidium melanogenum J7, Suhomyces pyralidae Y1117, Dekkera anomala V38, and Rhodotorula diarenensis J43 emerged as the best-performing biocontrol yeasts. Volatile organic compounds produced by the four yeasts were also identified and included in fruit bioassays using pears and tomatoes. Various VOCs, including 1-butanol, 3-methylbutanol, and butyric acid, were linked to the antagonistic properties of the selected yeasts. Lastly, the four chosen yeast strains significantly mitigated post-harvest spoilage caused by B. cinerea and F. fujikuroi in pear and tomato fruits, with D. anomala V38 exhibiting the greatest inhibitory activity. These findings underscore a potential sustainable and efficient approach to reducing mould-induced post-harvest spoilage while reducing reliance on synthetic fungicides.