Department of Food Engineering, Faculty of Agriculture, Cukurova University, Adana, Turkey.
Yeast. 2020 Sep;37(9-10):437-448. doi: 10.1002/yea.3501. Epub 2020 Jun 4.
Epiphytic yeasts were isolated from different cultivars of apples and lemons and identified by a combination of PCR-RFLP of 5.8S rRNA region and sequencing of D1/D2 domain of the 26S rRNA gene. Among 69 isolates, Aureobasidium pullulans GE17 and Meyerozyma guilliermondii KL3 strains showed the greatest antagonistic activity against two significant apple and lemon postharvest pathogens, Penicillium expansum DSM62841 (blue mold) and Penicillium digitatum DSM2750 (green mold), after preliminary screening. Yeasts were applied as single and mixed cultures with two different cell concentrations of 10 and 10 cells/ml in the present study. It was determined that antagonistic activity of two yeast strains studied emerged with a combination of several mechanisms of action including competition for space and nutrients, production of volatile organic compounds (VOCs), secretion of extracellular lytic enzymes and inhibition of fungal spore germination. The highest inhibition of mycelial growth on P. expansum DSM62841 and P. digitatum DSM2750 (83.4% and 74.7%, respectively) was achieved by utilization of single culture of A. pullulans GE17. Otherwise, the application of mixed culture at the ratio of 10 cells/ml inhibited spore germination of both pathogens from 86% to 95%. Results of this study suggest that an increase in yeast cell concentrations positively affected their biocontrol activity against blue and green molds. According to the results, employing single culture of M. guilliermondii KL3 did not exhibit effective antagonistic activity against blue and green molds. However, utilization of A. pullulans GE17 alone and mixed culture showed succesfull controlling against both P. expansum DSM62841 and P. digitatum DSM2750.
从不同品种的苹果和柠檬中分离出了附生酵母，并通过 5.8S rRNA 区域的 PCR-RFLP 和 26S rRNA 基因的 D1/D2 结构域测序相结合的方法进行了鉴定。在 69 株分离株中，经过初步筛选，出芽短梗霉 GE17 和毕赤酵母 KL3 菌株对两个重要的苹果和柠檬采后病原菌——扩展青霉 DSM62841（青霉）和桔青霉 DSM2750（绿霉）表现出最大的拮抗活性。在本研究中，酵母被应用于单一和混合培养，两种不同的细胞浓度分别为 10 和 10 个细胞/ml。研究确定，所研究的两种酵母菌株的拮抗活性是通过几种作用机制的组合产生的，包括空间和营养物质的竞争、挥发性有机化合物（VOCs）的产生、细胞外裂解酶的分泌和真菌孢子萌发的抑制。利用出芽短梗霉 GE17 的单一培养，对 P. expansum DSM62841 和 P. digitatum DSM2750 的菌丝生长抑制率最高，分别达到 83.4%和 74.7%。否则，以 10 细胞/ml 的比例应用混合培养，可将两种病原菌的孢子萌发抑制率从 86%提高到 95%。本研究结果表明，增加酵母细胞浓度可显著提高其对青霉和绿霉的生物防治活性。根据结果，单独使用毕赤酵母 KL3 单一培养对青霉和绿霉没有表现出有效的拮抗活性。然而，单独使用出芽短梗霉 GE17 或混合培养对 P. expansum DSM62841 和 P. digitatum DSM2750 都显示出成功的控制作用。
