Antagonistic Yeast Research Articles

Carboxymethyl cellulose-induced Cryptococcus laurentii improves disease resistance and regulates phenylpropane and reactive oxygen metabolism in grapefruit

Green mould disease poses a significant threat to the citrus industry. Cryptococcus laurentii can stimulate the fruit defence system, whereas the use of antagonistic yeast alone demonstrates limited efficacy. This study investigated the molecular mechanisms of C. laurentii cultured with carboxymethyl cellulose (CMCC. laurentii), and evaluated the effects of CMCC. laurentii on phenylpropane and reactive oxygen metabolism in grapefruit fruit. Transcriptome analysis revealed that the upregulation of gene expression associated with yeast growth and antagonistic ability occurred in CMCC. laurentii after 72 h cultivation. Meanwhile, CMCC. laurentii reduced lesion diameter and disease incidence in fruit. This treatment promoted phenylpropane metabolism by activating PAL, C4H, 4CL, POD, and PPO and increasing the secondary metabolites. CMCC. laurentii also activated the AsA-GSH cycle, enhanced the activities of SOD and CAT, and reduced the accumulation of H2O2 and O2•-. The results suggested that CMCC. laurentii maintained high postharvest fruit quality in grapefruit fruit by elevating the phenylpropane and reactive oxygen metabolism.

The presence of a significant endophytic fungus in mycobiome of rice seed compartments

Seed microbial communities have been known to have a crucial role in the life cycle of a plant. In this study, we examined the distribution of the fungal communities in three compartments (husk, brown rice, and milled rice) of the fourteen rice seed samples. Ten fungal genera distributed throughout the three compartments of the rice seeds were identified as the core mycobiome of the rice seeds, regardless of collecting regions or cultivars. Based on the diversity analysis, the distribution of the fungal community in milled rice was found to be more diversified, evenly distributed, and differently clustered from the other two compartments. Among the core mycobiome, Moesziomyces dominated almost 80% of the fungal communities in the outer compartments of rice seeds, whereas the abundances of other endophytic pathogenic fungi declined. Our results provide that antagonistic yeast Moesziomyces may be able to control the endogenous pathogenic fungal communities in rice seeds, hence maintaining the quality of rice seeds. In addition, the distribution of fungal communities differs depending on the rice seed’s compartment, indicating that the compartment can affect the distribution of the seed microbial community.

Genome-wide investigation and analysis of U-box E3 ubiquitin-protein ligase gene family in kiwifruit (Actinidia chinensis) in response to the yeast antagonist, Wickerhamomyces anomalus

ABSTRACT Although the ubiquitin ligase U-box protein family is a vital component of plant development and stress response, the exact role of kiwifruit U-box genes family is not known. The study identified 73 putative U-box genes from the kiwifruit genome. Chromosomal localisation, phylogenetic analysis, physicochemical properties, gene structure, motifs, and promoters of these genes were analysed. Distribution of Actinidia chinensis PUB (AcPUB) genes exhibited varying densities across 27 chromosomes. The study found that U-box clusters were classified into groups I–VII in phylogenetic analyses of a variety of plants, including kiwifruit, Arabidopsis thaliana, and rice, with most of the genes in kiwifruit being related to rice. The conserved motif analyses revealed that all the AcPUB genes have typical U-box structural domains. Analysis of the cis-acting elements suggested that AcPUBs expression may be responsive to several hormones and stresses. RNA-Seq analysis showed that six kiwifruit U-box genes were differentially expressed after induction by Wickerhamomyces anomalus, suggesting a potential involvement of these U-box genes in the kiwifruit's response to W. anomalus, which might include mechanisms related to resistance. Overall, our findings provide valuable insights into the function and structure of U-box genes that will help develop new genomic technologies and study plant resistance.

Efficacy of Postharvest Application of Aureobasidium pullulans to Control White Haze on Apples and Effect on the Fruit Mycobiome

White haze, an emerging disorder caused by extensive fungal growth on the apple surface, results in a compromised fruit quality and decreased marketability. The use of biological control agents could be an interesting tool to reduce its development. This work aimed to test the efficacy of two Aureobasidium pullulans strains (AP2 and PL5) in controlling white haze on stored apples. An in vivo trial was conducted by inoculating fruits with white haze causal agents (Entyloma belangeri, Golubevia pallescens, Tilletiopsis washingtonensis) and treating them with the antagonistic yeasts. Three commercial biofungicides were also included in the trial. Both A. pullulans strains, along with the Metschnikowia fructicola-based product, reduced white haze incidence after 110 days of storage at 1 ± 1 °C and after 7 days of shelf life. Furthermore, the effect of A. pullulans application on the fruit fungal microbiome was assessed. A significant impact of apple matrix and treatment on the mycobiome composition was observed. Analyses showed a good colonization of A. pullulans on the treated apples, both epiphytically and endophytically. A decrease in white haze-related fungi abundance was observed in the treated fruits. Additionally, a reduction of Ramularia spp. and modifications in the abundance of other fungal genera were detected after storage and shelf life.

Identification and evaluation of an endophytic antagonistic yeast for the control of gray mold (Botrytis cinerea) in apple and mechanisms of action

Gray mold, caused by Botrytis cinerea, is a prevalent postharvest disease of apple that limits their shelf life, resulting in significant economic losses. The use of antagonistic microorganisms has been shown to be an effective approach for managing postharvest diseases of fruit. In the present study, an endophytic yeast strain PGY-2 was isolated from apples and evaluated for its biocontrol efficacy against gray mold and its mechanisms of action. Results indicated that strain PGY-2, identified as Bullera alba, reduced the occurrence of gray mold on apples and significantly inhibited lesion development in pathogen-inoculated wounds. Gray mold control increased with the use of increasing concentrations of PGY-2, with the best disease control observed at 108 cells/mL. Notably, Bullera alba PGY-2 did not inhibit the growth of Botrytis cinerea in vitro indicating that the yeast antagonist did not produce antimicrobial compounds. The rapid colonization and stable population of PGY-2 in apple wounds at 4 °C and 25 °C confirmed its ability to compete with pathogens for nutrients and space. PGY-2 also had a strong ability to form a biofilm and enhanced the activity of multiple defense-related enzymes (POD, PPO, APX, SOD, PAL) in host tissues. Our study is the first time to report the use of Bullera alba PGY-2 as a biocontrol agent for postharvest diseases of apple and provide evidence that Bullera alba PGY-2 represents an endophytic antagonistic yeast with promising biocontrol potential and alternative to the use of synthetic, chemical fungicides for the control of postharvest gray mold in apples.

Evaulation of Effective Antagonistic Yeasts in Kalasin Province, a Biocontrol Agent against the Fungal Colletotrichum capsici Caused Anthracnose Diseases in Chili Fruits

Primary screening of epiphytic and endophytic yeasts, the majority yeast was found from rhizosphere soil (21 isolates, 31.81%), and 5 antagonistic yeasts can have inhibited the growth of mycelia of C. capsici up to 60%. Efficacy of five antagonistic yeasts were screened under plant nurseries conditions. The result found all isolates were tested and compared with control and chemical plots. The result of plant height showed that, yeast isolate KS34 had highest of plant height at 45.80 cm. For the result of branch per plant of chili plant found isolate KS37 showed highest of branch per plant at 16.60 branches and the flower of chili per plant presented that isolate KS37 had highest of flower at 18.60 flowers. The result of anthracnose disease control by antagonistic yeasts in disease incidence and category mean as plant resistance. These results found that, Isolates KS46 had a great disease incidence at 7.80% that mean this isolate prove chili plant to resistance to C. capsisci. Addition, isolate KS46 had highest of activity of chitinase enzyme at 170.72 U/ml. Isolate KS46 identified by D1/D2 domain of 26S ribosomal DNA sequencing. The sequence analysis showed maximum identity of 100% with Candida haemulonii. This assumed C. haemulonii was showed the best to control C. capsici. For confirmed this result, all isolates were determined the mode of action by studied in relationship between antagonist isolates. The action of yeast isolate could competition the nutrient with mycelia of pathogen. This mode effect to C. capsici loss nutrient caused the pathogen get stuck to braked and died later.

The Effect of Yeast Antagonist Isolated from the Fermentation of Cocoa Beans (Theobroma cacao) from Lampung, Indonesia, on the Growth of Aspergillus flavus UNJCC F-55

Mold is one of the microorganisms that causes damage to cocoa fruit because it produces mycotoxins as secondary metabolites that can decrease the crop yield. One type of pathogenic mold that destroys cocoa fruit is Aspergillus flavus. A. flavus produces aflatoxin B1 which is the most potent hepatotoxin and carcinogen to humans. Amongst the most effective ways to avoid alpha-toxin contamination in cocoa beans is to inhibit the growth of A. flavus in the beans. However, the use of pesticides and fungicides can increase the development of resistant strains of fungi and have a negative impact on the environment and human health. Therefore, we need other alternatives such as bio-control agents using antagonistic microorganisms, including yeasts. Thus, this study aims to characterize yeasts isolated from the fermented cocoa beans (Theobroma cacao) from Lampung, Indonesia, and evaluate their ability to inhibit the growth of Aspergillus flavus UNJCCF-55. The methods used were yeast screening, dual culture technique for antagonistic test, and morphological characterization. The 37ºC-growth screening gave 89 out of 98 yeast isolates. The subsequent antagonist test resulted in 13 isolates with the highest inhibition zone against A. flavus UNJCCF-55. These yeast isolates were macroscopically of smooth surface, butyrous texture, milky white color, irregular edges, and convex elevation. Microscopic observation showed that the isolates have oval cell shape, asexual reproduction of budding, and non-hyphae structure.
 Keywords: yeast antagonist, cocoa fermentation, aspergillus flavus

Antagonistic yeast and trehalose-enriched gelatin film: A bioactive antifungal packaging film for cherry tomato preservation

To extend the shelf-life of cherry tomatoes infected with Botrytis cinerea, this study analyzed the effect of Pichia membranifaciens (PM) on a composite film of gelatin (Gel) and trehalose (Tre), and explored the effect of different concentrations of trehalose on the yeast in the bioactive film and its control effect on cherry tomatoes. Scanning electron microscopy showed that Tre/Gel-based film can be applied as effective carriers to protect the cellular integrity of PM. Fourier-transform infrared spectroscopy, thermogravimetric analysis, and tests of mechanical properties showed that there was interaction between PM and the Tre/Gel base film, which maintained the thermal stability of the base film. The addition of PM reduced the water vapor permeability, hygroscopicity, and moisture content of the Tre/Gel base film, effectively extending the active film's storage time. This study also explored the growth curve of PM and found that 15% trehalose was effective in maintaining PM activity and could result in a 30-day survival rate of 62% for PM in Tre/Gel films, with 72.41% inhibition of B. cinerea. Finally, the PM/Tre/Gel film significantly reduced the incidence of decay in cherry tomatoes and improved the storage quality and fungal resistance of the fruit. Thus, PM/Tre/Gel films may be applied as a new antifungal packaging material for the preservation of fresh fruit.

Transcriptomic analysis to elucidate the molecular mechanisms underlying the growth advantage of Kluyveromyces marxianus XZ1 and the development of resistance in apple induced by XZ1

The preceding study demonstrated that Kluyveromyces marxianus XZ1 (XZ1) exhibits potential as a biological agent for combating disease by P. expansum in apple fruit. This potential is primarily attributed to its capacity for competing for resources and space, as well as activating certain genes involved in the transduction of plant hormone signals. In this study, transcriptomic analysis was performed on the interaction system of XZ1 and apple to investigate the detail molecular mechanisms of the yeast to develop competitive advantage and the molecular mechanisms of the apple to develop defense response action at the gene expression level. The transcriptome analysis of XZ1 in apple indicated that the meiosis pathway was activated to promote rapid proliferation of the yeast in apple. Autophagy, ubiquitin-mediated proteolysis, and the starch and sucrose metabolism pathway are induced to generate vital nutrients and energy for yeast proliferation. The transcriptome analysis of apple revealed upregulation in the expression levels of genes associated with transcription factors (TFS) involved in pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) following treatment with XZ1. This finding suggests that XZ1 activates PTI and ETI in apple, thereby promoting disease resistance. Moreover, the yeast treatment induced the activation of ethylene and jasmonate signal transduction pathways, which play a crucial role in regulating disease resistance development in apple. Additionally, the yeast treatment resulted in the enhancement of lignin biosynthesis, serving as a protective mechanism for the apple against potential threats, as observed in the response to XZ1 treatment. The findings of this study establish a theoretical foundation for elucidating the molecular mechanism underlying the growth advantage of antagonistic yeast in the host and the induced resistance in apple. Additionally, this study offers a substantial repertoire of gene resources that can be utilized to enhance yeast biocontrol efficacy and bolster the disease resistance of apple through the application of molecular biology techniques.

Antagonistic yeast: Eco-friendly tool for management plant diseases

Antagonistic yeast: Eco-friendly tool for management plant diseases

Recruiting grape‐isolated antagonistic yeasts for the sustainable bio‐management of Botrytis cinerea on grapes

AbstractBotrytis cinerea is the causative agent of grey mould disease in grapes, which was linked to significant postharvest losses. This study examined three grape‐isolated yeasts (Metschnikowia aff. fructicola, Metschnikowia pulcherrima, and Hansenispora uvarum) through in vitro and in vivo tests on detached grape berries against grey mould, as well as the elucidation of their possible mechanisms of action. The antifungal mechanism of action of yeasts was determined by the lytic enzyme activity, inhibition of spore germination, biofilm activity, iron depletion, diffusible metabolites, wound‐site colonisation, mycocin, and volatile organic compounds (VOCs) production. The highest in vitro efficacy (83.13%) was observed on M. aff. fructicola, followed by M. pulcherrima (82.10%) and H. uvarum (71.66%). Metschnikowia yeasts exhibited comparable enzyme activities, including protease, β‐1,3 glucanase, gelatinase chitinase, and cellulase, while H. uvarum had a poor enzymatic activity with chitinase and gelatinase. M. aff. fructicola showed relatively higher iron depletion activity than M. pulcherrima, while M. pulcherrima outperformed via diffusible metabolites. All yeast cultures significantly reduced spore germination by at least 86%. Overall, M. aff. fructicola exhibited the highest biocontrol activity with its iron depletion, inhibition of conidial germination, biofilm formation, VOCs, and well colonisation on grape berries. M. aff. fructicola 1‐UDM outperformed all other yeasts by significantly reducing disease incidence and lesion diameter values (93.4% and 94.3%, respectively). Remarkably, H. uvarum VOCs demonstrated potential as a biofumigant for suppressing grey mould. All yeasts are well adapted to their ecological niche to bio‐protect grapes from grey mould disease.

A transcriptome profile of Wickerhamomyces anomalus incubated with chitosan revealed dynamic changes in gene expression and metabolic pathways

Previous studies have shown that Wickerhamomyces anomalus can control postharvest diseases of fruits and incubation of the yeast with chitosan can improve its efficiency. In this study, transcriptome study was conducted to determine molecular mechanisms involved in the yeast-chitosan interaction. The bioinformatics analysis of the RNA-seq data confirmed that incubating W. anomalus with 1 % chitosan for 24 h significantly altered the expression of differential genes involved in yeast metabolic and cellular activities. Genes involved in ethyl acetate production, reactive oxygen species regulation, cell wall reinforcement, stress resistance, and signalling were all significantly up-regulated. Pathways which have significant role in the yeast growth and reproduction, energy production, cellular homeostasis, signal transduction, catalytic, and antioxidant activities were significantly enriched. In general, incubation of the yeast with chitosan genes metabolic pathways which are important for the yeast survival, adaptation, and reproduction. Molecular studies are important in providing fundamental theoretical foundation for the practical application of antagonistic yeasts for future uses. As a result, this research will be an input for use of the antagonistic yeast as microbial or biochemical pesticides instead of synthetic chemicals which have both health and environmental effects.

The biopreservative properties of Metschnikowia pulcherrima LMA 2038 and Trichosporon asahii LMA 810 in a model fresh cheese, are presented

The diversity of microorganisms present in cheeses contributes to their typicity and organoleptic properties. Inhibitory strains found in these ecosystems could be used as biopreservative agents in order to replace chemicals, which are increasingly decried by consumers. Here, we isolated from cheese two yeasts named, Metschnikowia pulcherrima LMA 2038 and Trichosporon asahii LMA 810, which are active against fungi, such as Yarrowia lipolytica LMA 800, Rhodotorula mucilaginosa LMA 808, Cladosporium cladosporioides LMA 31, and Penicillium commune LMA 72, as well as against bacteria, such as Listeria innocua ATCC 33090 and Clostridium tyrobutyricum LMG 1285. When cultivated on model fresh cheese, these antagonistic yeasts significantly reduced the number of Y. lipolytica LMA 800 and R. mucilaginosa LMA 808. Preliminary data enabled us to establish a snapshot of the molecules responsible for these antifungal and antibacterial inhibitions. The molecules presumed to be present in the culture supernatant were subjected to various treatments, including heat, pH variations and enzymatic treatments. Thus, we hypothesize that different antimicrobial compounds were produced by the aforementioned antagonistic yeasts, and these molecules act in a target strain-specific manner. In summary, our findings demonstrate that cheeses possess an innumerable supply of antagonistic microbial strains, which can be exploited in the field of biopreservation to substitute chemicals and extend the shell-life of food products, including cheese.

The potentiality of Wickerhamomyces anomalus against postharvest black spot disease in cherry tomatoes and insights into the defense mechanisms involved

Our previous study revealed that Wickerhamomyces anomalus effectively inhibited Botrytis cinerea disease in cherry tomatoes. However, the potentiality of W. anomalus against black spot disease in cherry tomatoes as well as possible mechanisms related to this efficacy remain unclear. In our current study, we investigated the efficacy of W. anomalus against black spot disease in cherry tomatoes, and the molecular mechanisms related to disease-resistance response of W. anomalus treated cherry tomatoes were also investigated by transcriptome analysis. The results exhibited that W. anomalus successfully controlled postharvest black spot disease of cherry tomatoes caused by Alternaria alternata. Furthermore, W. anomalus vigorously controlled the spore germination and reduced the germ tube elongation of A. alternata. The physiological mechanisms by which W. anomalus inhibited the black spot decay in cherry tomatoes mainly through enhancing the ascorbate peroxidase (APX) and chitinase (CHI), and reducing the content of malondialdehyde (MDA). In addition, based on transcriptome technology, W. anomalus could up-regulate genes involved in several important KEGG pathways, including amino sugar and nucleotide sugar metabolism pathway, selenocompound metabolism pathway, linoleic acid metabolism pathway, and galactose metabolism pathway. These genes may help the fruit to enhance the enzyme activities and nutritional values of cherry tomatoes, synthesize the regulatory molecules in plant disease response as well as plant growth and development, increase the defense and oxidation resistance of the fruit during and after harvesting, and trigger ROS induced resistance in cherry tomatoes. Ultimately, W. anomalus has been proved as a biocontrol agent which could effectively control black spot disease in cherry tomatoes caused by A. alternata. This study can provide theoretical reference for the practical application of antagonistic yeasts in the biological control of postharvest diseases of cherry tomatoes.

Potential of yeasts as biocontrol agents against Fusarium graminearum in vitro and on corn.

The antifungal effect of the yeast species Kluyveromyces marxianus, Meyerozyma caribbica, and Wickerhamomyces anomalus was evaluated against two Fusarium graminearum strains (FRS 26 and FSP 27) in vitro and on corn seeds. The antifungal effect of the yeasts against F. graminearum was evaluated using scanning electron microscopy and extracellular chitinase and glucanase production to further elucidate the biocontrol mode of action. In addition, the germination percentage and vigor test were investigated after applying yeast on corn seeds. All the yeast strains inhibited fungal growth in vitro (57.4%-100.0%) and on corn seeds (18.9%-87.2%). In co-culture with antagonistic yeasts, F. graminearum showed collapsed hyphae and turgidity loss, which could be related to the ability of yeasts to produce chitinases and glucanases. The three yeasts did not affect the seed corn germination, and W. anomalus and M. caribbica increased corn seed growth parameters (germination percentage, shoot and root length, and shoot dry weight). Meyerozyma caribbica and W. anomalus showed satisfactory F. graminearum growth inhibition rates and did not affect seed growth parameters. Further studies are required to evaluate the application of these yeasts to the crop in the field.

Glycine Enhances Oxidative Stress Tolerance and Biocontrol Efficacy of Sporidiobolus pararoseus against Aspergillus niger Decay of Apples.

Apples are deeply loved by people because of their rich nutritional value, but they are susceptible to rotting. The use of antagonistic yeast is a promising method for controlling postharvest fruit diseases, but biocontrol efficacy of yeast will be weakened in environmental stress. In this study, the effects of glycine (Gly) on the oxidative stress tolerance and the biocontrol efficacy of Sporidiobolus pararoseus (S. pararoseus) against Aspergillus niger (A. niger) are discussed. Under the stimulation of H2O2, the yeast cells treated with Gly (1 mM) showed lower ROS content, less mitochondrial impairment and cellular oxidative damage, and the cell survival rate was significantly higher than Gly-untreated yeast. The yeast cells exposed to Gly significantly increased the activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and the content of glutathione (GSH). Notably, Gly-treated yeast cells had better biocontrol efficacy against A. niger in postharvest apples. The lesion diameter and decay incidence were reduced by 17.67 mm and 79.63% compared to the control, respectively, when S. pararoseus was treated with 1 mM Gly. Moreover, Gly-treated yeast increased the antioxidant enzymes activities and their gene expression were up-regulated in apples. These results indicated that 1 mM Gly not only reduced the oxidative damage of yeast, but also induced resistance-related enzymes of apples under oxidative stress, which contributed to enhancing the biocontrol efficacy of S. pararoseus against A. niger in apples.

ФУЗАРИОЗ ВИНОГРАДА: ОТ СКРИНИНГА ДО БИОКОНТРОЛЯ ДРОЖЖЕВЫМИ ГРИБАМИ

The grapevine (Vitis vinifera L.) is one of the most important fruit crops in the world. Cultivated grape varieties are considerably affected by a large number of pathogenic microorganisms that cause diseases during the growing season impacting the quantity and quality of the crop its processing and export. Potential threats include bacteria, fungi, oomycetes or viruses with different life cycles, infection mechanisms and survival strategies. In recent years there has been an increase in grape fusarium and a change in the complex of its pathogens in various countries. Fusarium of grapes being a relatively new and dangerous disease negatively affects grape must. A complex of fungi of the genus Fusarium is involved in the defeat of grapes the main feature of which is the ability to produce mycotoxins. The species composition and the proportion of each species in the complex of detected fungi can vary with changes in the conditions of cultivation or storage of grapes, which is accompanied by changes in the spectrum of mycotoxins. Therefore, effective Fusarium control methods need to be introduced in the field before harvest especially using alternative methods to pesticides such as biocontrol. One of the most promising but at the same time poorly developed is the use of antagonists of mycotoxin producers. The use of yeast fungi as a biologized technology of protection against Fusarium in viticulture is relevant. Frequently reported yeast antagonists include strains belonging to the genus Pichia, Meyerozyma, Rhodotorula, Metschnikowia Saccharomyces, Candida, Hanseniaspora, and the yeast-like fungus Aureobasidium pullulans. The review is devoted to the characterization of Fusarium fungi pathogenic for grapes and perspectives of application of biological means of their control with the help of yeast fungi.

Efficacy of Wickerhamomyces anomalus in the biocontrol of black spot decay in tomatoes and investigation of the mechanisms involved

Black spot caused by Alternaria alternata is a common postharvest disease of tomato. In the current study, Wickerhamomyces anomalus was used to control the disease. The experimental results showed that W. anomalus had the effect of controlling black spot disease, and 108 cells/mL of W. anomalus was the most suitable concentration for controlling the disease. W. anomalus has the ability to reduce the spore germination and inhibit germ tubes growth of A. alternata, and its volatile substances also have inhibitory effects on pathogenic fungi. W. anomalus can reduce the natural decay rate of tomato, retain postharvet quality of tomato, and increase the contents of ascorbic acid and lycopene. In addition, W. anomalus can significantly reduce the H2O2, O2– production rate, and MDA contents of tomato. It increased the enzymatic activities of catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPX), glutathione S-transferase (GST), and increased the content of glutathione (GSH). Furthermore, the yeast improved the ability of tomato to resist oxidative stress, thereby better resisting the pathogen infection. Generally, this study will significantly contribute to use antagonistic yeasts or their products to control postharvest diseases of horticultural produces.

Biocontrol Efficacy of Metschnikowia spp. Yeasts in Organic Vineyards against Major Airborne Diseases of Table Grapes in the Field and in Postharvest.

The aim of this work was to evaluate the efficacy of two antagonistic yeasts, Metschnikowia pulcherrima strain MPR3 and M. fructicola strain NRRL Y-27328 (commercial product NOLI), applied in addition to the "on-farm biological treatments" (BIO) carried out during the production season, for the containment of powdery mildew and grey mould diseases on organic table grapes 'Italia'. The yeast strains were applied in the field three times, and their efficacy was evaluated during the production season and under postharvest conditions. Overall, M. pulcherrima MPR3 combined with BIO treatments reduced disease incidence caused by Erysiphe necator and disease incidence and severity caused by Botrytis cinerea with values between 67.8% and 86.2%, showing higher efficacy than BIO treatments applied alone and in combination with NOLI. Field treatments based on BIO+MPR3 maintained their performance also during fruit storage, protecting grape berries from grey mould development to a greater extent than the other treatments (disease reduction of about 98%). Thus, the presence of M. pulcherrima MPR3 seems to improve disease management both in the field and in postharvest environments, without negative impacts on grape microbial communities. These findings highlight the potential of M. pulcherrima MPR3 as a promising alternative strategy for disease control in organic vineyards and in postharvest, providing sustainable solutions to improve food quality and safety.

Exploring yeast-based microbial interactions: The next frontier in postharvest biocontrol.

Fresh fruits and vegetables are susceptible to a large variety of spoilage agents before and after harvest. Among these, fungi are mostly responsible for the microbiological deteriorations that lead to economically significant losses of fresh produce. Today, synthetic fungicides represent the first approach for controlling postharvest spoilage in fruits and vegetables worldwide. However, the emergence of fungicide-resistant pathogen biotypes and the increasing awareness of consumers towardthe health implications of hazardous chemicals imposed an urgent need to reduce the use of synthetic fungicides in the food supply; this phenomenon strengthened the search for alternative biocontrol strategies that are more effective, safer, nontoxic, low-residue, environment friendly, and cost-effective. In the last decade, biocontrol with antagonistic yeasts became a promising strategy to reduce chemical compounds during fruit and vegetable postharvest, and several yeast-based biocontrol products have been commercialized. Biocontrol is a multipartite system that includes different microbial groups (spoilage mold, yeast, bacteria, and nonspoilage resident microorganisms), host fruit, vegetables, or plants, and the environment. The majority of biocontrol studies focused on yeast-mold mechanisms, with little consideration for yeast-bacteria and yeast-yeast interactions. The current review focused mainly on the unexplored yeast-based interactions and the mechanisms of actions in biocontrol systems as well as on the importance and advantages of using yeasts as biocontrol agents, improving antagonist efficiency, the commercialization process and associated challenges, and future perspectives.