Biocontrol ability and action mechanisms of Aureobasidium pullulans GE17 and Meyerozyma guilliermondii KL3 against Penicillium digitatum DSM2750 and Penicillium expansum DSM62841 causing postharvest diseases

Abstract

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 6 and 10 8 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 8 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. K E Y W O R D S antagonistic yeast, Aureobasidium pullulans, biocontrol, blue mold, green mold, Meyerozyma guilliermondii, mode of action 1 | INTRODUCTION Increased consumer awareness of the relationship between nutrition and health issues led to an increase in fruit and vegetable consumption. According to the data from Food and Agriculture Organization of the United Nations (FAO, 2017), 865.6 million tons of fresh fruit in 65.2 million hectares, 1.1 billion tons of fresh vegetables in 57 million hectares, hence approximately two billion tons of fresh fruit and vegetables have been produced in total. However, after harvesting, fresh fruit and vegetables undergo various spoilages resulting in economic

Fungal Community Analyses of Endophytic Fungi from Two Oak Species, Quercus mongolica and Quercus serrata, in Korea

“…Among Aureobasidium spp., A. pullulans has been identified as one of the biocontrol agents to control various fruit postharvest pathogens such as Monilinia laxa on plums, peaches, sweet cherries, apricots, and table grapes [63][64][65][66]; Botrytis cinerea on apples, sweet cherries, tomatoes. and table grapes [63,[66][67][68]; Penicillium expansum on apples, lemons [63,67,69]; Monilinia fructicola, Monilinia polystroma and Monilinia fructigena on sweet cherries, peaches, and apricots [64,65]; Colletotrichum acutatum on apples [67]; Penicillium italicum and Penicillium digiatum on citruses, apples, and lemons [67,69]. Aureobasidium pullulans was also used to control plant pathogens, namely Phytophthora infestans causing tomato late blight [70], Rhizoctonia solani causing damping-off in tomato, bean, and soybean seedlings [71,72], Fusarium culmorum causing Fusarium head blight of common wheat (Triticum aestivum) [73], and Neofusicoccum parvum causing stem canker disease in apple trees [74].…”

Trunk Surgery as a Tool to Reduce Foliar Symptoms in Diseases of the Esca Complex and Its Influence on Vine Wood Microbiota

“… Ascomycota Herpotrichiellaceae E ■; ▲ 2.0; 0.7 [ 28 ] Fomitiporia mediterranea Basidiomycota Hymenochaetaceae P ■; ▲; ● 45.0; 5.9; 55.0 [ 6 , 79 , 82 , 130 , 143 , 144 , 145 , 146 ] Leptosphaeria sp. Ascomycota Leptosphaeriacea E; S ▲ 0.1 [ 80 , 88 ] Meyerozyma guilliermondii Ascomycota Debaryomycetaceae E ■; ▲ 0.1; 2.3 [ 147 , 148 ] Penicillium sp. Ascomycota Aspergillaceae E; P; S ■; ▲ 0.9;5.5 [ 28 , 80 ,...…”

Increased Organic Fertilizer and Reduced Chemical Fertilizer Increased Fungal Diversity and the Abundance of Beneficial Fungi on the Grape Berry Surface in Arid Areas

“…In the production of organic apples and pears, A. pullulans is used as a biocontrol agent for fire blight protection (Temple et al, 2020). Utilization of A. pullulans was shown to be successful in controlling against both P. expansum and Penicillium digitatum (Agirman and Erten, 2020). A better understanding of these interactions may provide novel opportunities to develop creative biocontrol methods against plant pathogens (Sebastien et al, 2015).…”