Antagonistic Yeast Research Articles

Isolation and in vivo screening of yeast antagonists for the control of Botrytis cinerea and Penicillium expansum of pome fruit

ISHS V International Symposium on Postharvest Pathology: From Consumer to Laboratory-Sustainable Approaches to Managing Postharvest Pathogens Isolation and in vivo screening of yeast antagonists for the control of Botrytis cinerea and Penicillium expansum of pome fruit

Analysis of Stored Wheat Grain-Associated Microbiota Reveals Biocontrol Activity among Microorganisms against Mycotoxigenic Fungi.

Wheat grains are colonized by complex microbial communities that have the potential to affect seed quality and susceptibility to disease. Some of the beneficial microbes in these communities have been shown to protect plants against pathogens through antagonism. We evaluated the role of the microbiome in seed health: in particular, against mycotoxin-producing fungi. Amplicon sequencing was used to characterize the seed microbiome and determine if epiphytes and endophytes differ in their fungal and bacterial diversity and community composition. We then isolated culturable fungal and bacterial species and evaluated their antagonistic activity against mycotoxigenic fungi. The most prevalent taxa were found to be shared between the epiphytic and endophytic microbiota of stored wheat seeds. Among the isolated bacteria, Bacillus strains exhibited strong antagonistic properties against fungal pathogens with noteworthy fungal load reduction in wheat grain samples of up to a 3.59 log10 CFU/g compared to untreated controls. We also found that a strain of the yeast, Rhodotorula glutinis, isolated from wheat grains, degrades and/or metabolizes aflatoxin B1, one of the most dangerous mycotoxins that negatively affects physiological processes in animals and humans. The mycotoxin level in grain samples was significantly reduced up to 65% in the presence of the yeast strain, compared to the untreated control. Our study demonstrates that stored wheat grains are a rich source of bacterial and yeast antagonists with strong inhibitory and biodegradation potential against mycotoxigenic fungi and the mycotoxins they produce, respectively. Utilization of these antagonistic microorganisms may help reduce fungal and mycotoxin contamination, and potentially replace traditionally used synthetic chemicals.

Suppression of Bacterial Leaf Spot by Green Synthesized Silica Nanoparticles and Antagonistic Yeast Improves Growth, Productivity and Quality of Sweet Pepper.

Plants are challenged with many kinds of biotic stresses caused by different living organisms, which result in various types of diseases, infections, and damage to crop plants and ultimately affect crop productivity. Plant disease management strategies based on current approaches are necessary for sustainable agriculture. A pot experiment was carried out under greenhouse conditions to evaluate the potential of green synthesized silica nanoparticles (SiO2-NPs) and antagonistic yeast (Saccharomyces cerevisiae) against pepper bacterial leaf spot disease, caused by Xanthomonas vesicatoria. In addition, to assess their efficacy and suppressive effects in reducing disease severity and improving sweet pepper growth, productivity, and quality. Results revealed that the combination of BCA (5%) and SiO2-NPs (150 ppm) was the most effective treatment for reducing disease severity and improving vegetative growth characters, mineral contents (N, P, K, Ca, Mg, and Si in leaves), as well as stimulating polyphenol oxidase (PPO) activity of sweet pepper leaves at 90 days from transplanting, while also at harvesting time enhancing sweet pepper fruit yield quality parameters significantly. In conclusion, green synthesized silica nanoparticles combined with antagonistic yeast have the potential to suppress a bacterial leaf spot disease with ecologically-sound management, while also boosting sweet pepper growth, productivity, and quality.

Integrated control of blue and gray molds of apples with antagonistic yeasts combined with carbon dioxide or ozone

Integrated control of blue and gray molds of apples with antagonistic yeasts combined with carbon dioxide or ozone

Biodegradation of mycotoxin patulin by the yeast Meyerozyma guilliermondii

Patulin is a well-known mycotoxin widely found in rotten fruits, produced by a series of toxigenic fungi, particularly Penicillium expansum. Patulin is hazardous to human and animal health. Meyerozyma guilliermondii is an antagonistic yeast that has been found to have biocontrol properties against blue mold disease in pears. But, it is not clear whether M. guilliermondii can degrade patulin. The present study aimed to investigate M. guilliermondii to degrade patulin and the possible mechanisms involved. The results showed that neither uptake of patulin by cells nor adsorption by cell wall components were involved in patulin elimination by M. guilliermondii. Extracellular metabolites also do not degrade patulin. The addition of cycloheximide to the M. guilliermondii cells decreased the capacity of patulin degradation. Enzymes induced by patulin had a more substantial degradation effect on patulin, which indicated that the patulin-degradation ability of M. guilliermondii was inducible. Our results confirmed that M. guilliermondii could degrade patulin. The intracellular enzymes of M. guilliermondii, particularly a short-chain dehydrogenase (SDR), carried out the degradation process. The degradation ability of M.guilliermondii towards patulin would be a novel approach for the elimination of patulin contamination.

Efficacy of an antifungal edible coating for the quality maintenance of Tarocco orange fruit during cold storage

This study evaluated the effectiveness of a novel pectin-based edible coating (PBEC), alone or added with the antagonistic yeast Wickerhamomyces anomalus BS91 (PBECY), in reducing postharvest rots of Tarocco orange fruit. Their antifungal efficacy was assessed in vitro and in vivo, as well as their ability to preserve fruit quality under refrigerated conditions on three different cultivars, comparing a commercial wax amended with a fungicide. For all the treatments, the decay incidence, physiological disorders, weight loss and physical-chemical parameters were evaluated. The in vivo test results indicated that PBECY enhanced the antifungal effect compared to PBEC, given the significant reduction (p ≤ 0.01) of Penicillium digitatum (PD) decay incidence (up to 90%). After 30 d of cold storage, both PBEC and PBECY reduced fruit decay (p ≤ 0.05) in all cultivars, with values between 0 and 1.2%, relatively to the untreated control (up to 10%). Pectin-coated fruit showed a cultivar-dependent weight loss, with values comparable or higher to the other treatments, respectively for T. Lempso and T. Messina, whereas weight loss in T. Sciara was higher only when coated with PBEC. Fruit physical and chemical parameters were preserved until 30 d of storage, thus demonstrating the potential of this edible coating for future industrial application.

Successful biocontrol of major postharvest and soil-borne plant pathogenic fungi by antagonistic yeasts

Fungal pathogens are the main biotic burden of productivity for economically important crops under field, greenhouse or postharvest conditions. The discovery and development of new environmental-friendly solutions, such as application of living organisms and their derivatives to control plant diseases and pests, are of enormous interest. This study presents the results of a mass screening designed to detect yeast strains with antagonistic activity against postharvest pathogens (Alternaria alternata, Penicillium expansum and Botrytis cinerea) and soil-borne diseases (Verticillium dahliae and Fusarium oxysporum). In fact, this is the first study that focuses on screening the antagonistic potential of a wide variety of yeast genera (13) and species (30) against vascular wilts. The results from in vivo trials demonstrated that fungal infected tomato plants, grown under hydroponic or soil conditions, showed a significant reduction in disease severity after yeast treatment. Wickerhamomyces anomalus Wa-32 was able to antagonise both pathogens and reduce the disease severity up to 40% (V. dahliae) and 50% (F. oxysporum) in soil conditions. In addition, this strain became endophytic in tomato plants. The features of Wa-32 are of enormous interest since no effective antagonistic biocontrol product is available for the simultaneous control of these two fungal pathogens. Postharvest assays with wounded tomato fruits showed that several strains displayed very high biocontrol levels against P. expansum and B. cinerea (up to 86 and 97% reduction in disease severity, respectively) but none of them showed protection against A. alternata. The best protection against B. cinerea was again achieved with W. anomalus Wa-32 and two Metschnikowia pulcherrima strains (Mp-22 and Mp-30). However, the best antagonistic strains of P. expansum were Candida lusitaniae Cl-28, Candida oleophila Co-13, Debaryomyces hansenii Dh-67 and Hypopichia pseudoburtonii Hp-54. These biocontrol effects were also demonstrated in grapes and apples.

New Isolated Metschnikowia pulcherrima Strains from Apples for Postharvest Biocontrol of Penicillium expansum and Patulin Accumulation.

Wild yeasts isolated from the surface of apples were screened for antagonistic activity against Penicillium expansum, the main producer of the mycotoxin patulin. Three antagonistic yeasts (Y33, Y29 and Y24) from a total of 90 were found to inhibit P. expansum growth. Identification by ITS region sequence and characterization showed that three selected isolates of yeast should be different strains of Metschnikowia pulcherrima. Several concentrations of the selected yeasts were used to study their in vitro antifungal effectivity against P. expansum on Petri dishes (plates with 63.6 cm2 surface) whereas their potential activity on patulin reduction was studied in liquid medium. Finally, the BCA that had the best in vitro antifungal capacity against P. and the best patulin degradation capacity was selected to be assessed directly on apples. All the selected strains demonstrated antifungal activity in vitro but the most efficient was the strain Y29. Isolated strains were able to reduce patulin content in liquid medium, Y29 being the only strain that completely reduced patulin levels within 120 h. The application of Y29 as biocontrol agent on the surface of apples inoculated with P. expansum, inhibited fungal growth and patulin production during storage. Therefore, the results shown that this yeast strain could be used for the reduction of P. expansum and its mycotoxin in apples or apple-based products by adapting the procedure application.

Trehalose supplementation enhanced the biocontrol efficiency of Sporidiobolus pararoseus Y16 through increased oxidative stress tolerance and altered transcriptome.

In the process of biological control, the antagonistic yeasts contend with various stresses that negatively influence yeasts' biocontrol efficiency. In the current study, we investigated the effect of trehalose supplementation on the biocontrol efficiency and oxidative stress tolerance of Sporidiobolus pararoseus Y16. S. pararoseus Y16, an antagonistic yeast cultured in trehalose supplemented medium, exhibited better biocontrol efficiency against Penicillium expansum and Aspergillus tubingensis in table grapes. Trehalose-treated S. pararoseus Y16 cells showed good proliferation efficiency and oxidative stress tolerance than untreated cells. Increased β-1,3-glucanase, catalase, superoxide dismutase activity, and low protein carbonylation were observed in trehalose-amended S. pararoseus Y16 upon H2 O2 exposure. The RNA sequencing results indicated that trehalose significantly altered the transcriptome of S. pararoseus Y16. The GO, KEGG, and COG annotations revealed that the differentially regulated genes corresponded to the various biological process of the yeast. Our findings suggested that trehalose use could enhance the biocontrol efficiency and oxidative stress tolerance of S. pararoseus Y16. Trehalose supplementation altered the transcriptome of S. pararoseus Y16, particularly the genes that correspond to amino acid metabolism, nucleotide metabolism, and protein modification. Thereby the oxidative stress tolerance and biological control efficiency of S. pararoseus Y16 was enhanced by trehalose. © 2021 Society of Chemical Industry.

Effect of Rhodotorula mucilaginosa on patulin degradation and toxicity of degradation products

ABSTRACT Rhodotorula mucilaginosa is an antagonistic yeast for which our research team has recently reported interesting biocontrol activities against blue mould decay of apples and a strong ability to decrease the patulin concentration in vivo. However, the possible mechanisms of patulin degradation by R. mucilaginosa and the toxicity of patulin degradation products remain unclear. In this study, the effect of R. mucilaginosa on patulin degradation and toxicity of degradation products were investigated, the results showed that viable cells of R. mucilaginosa are essential to patulin degradation. Also, R. mucilaginosa eliminated patulin without adsorbing it through its cell wall. The extracellular metabolites of R. mucilaginosa stimulated by patulin showed little degradation activity for patulin. Cycloheximide addition into the medium significantly decreased the patulin degradation capacity of R. mucilaginosa cells. The main patulin degradation product by R. mucilaginosa was ascladiol, which was proved non-toxic to human hepatoma (HepG2) cells at 0.625–10 g/mL. Furthermore, toxicological analysis using a confocal laser scanning microscope revealed that the degradation product induced cellular apoptosis to a lesser extent than patulin itself. This result offers an innovative method to detoxify patulin and limit the risks of patulin in fruits and vegetables using R. mucilaginosa.

The antagonistic Metschnikowia andauensis produces extracellular enzymes and pulcherrimin, whose production can be promoted by the culture factors

Biological control against microbial infections has a great potential as an alternative approach instead of fungicidal chemicals, which can cause environmental pollution. The pigment producer Metschnikowia andauensis belongs to the antagonistic yeasts, but details of the mechanism by which it inhibits growth of other microbes are less known. Our results confirmed its antagonistic capacity on other yeast species isolated from fruits or flowers and demonstrated that the antagonistic capacity was well correlated with the size of the red pigmented zone. We have isolated and characterized its red pigment, which proved to be the iron chelating pulcherrimin. Its production was possible even in the presence of 0.05 mg/ml copper sulphate, which is widely used in organic vineyards because of its antimicrobial properties. Production and localisation of the pulcherrimin strongly depended on composition of the media and other culture factors. Glucose, galactose, disaccharides and the presence of pectin or certain amino acids clearly promoted pigment production. Higher temperatures and iron concentration decreased the diameter of red pigmented zones. The effect of pH on pigment production varied depending of whether it was tested in liquid or solid media. In addition, our results suggest that other mechanisms besides the iron depletion of the culture media may contribute to the antagonistic capacity of M. andauensis.

Selecting Antagonistic Yeast for Postharvest Biocontrol of Colletotrichum gloeosporioides in Papaya Fruit and Possible Mechanisms Involved

Colletotrichum gloeosporioides causes anthracnose disease in papaya fruit resulting in tremendous economic loss due to its latent infection. This study aimed to evaluate the biocontrol activity of antagonistic yeasts against C. gloeosporioides in papaya and determine the possible mechanism involved. One hundred and ten yeast strains were isolated from different parts of the papaya plant. Among them, only five strains, namely F001, F006, L003, FL013 and LP010, showed more than 55% radial growth inhibition of C. gloeosporioides. These five potent yeast strains were further evaluated in vitro and in vivo. The results indicated that strain F001 had the strongest biocontrol activity based on spore germination and fungal growth inhibition. In vivo, the strain F001 caused 66.7% and 25% reductions in disease incidence and severity, respectively. Based on molecular identification, the strain F001 was confirmed as Trichosporon asahii. Despite there was no significant induction of defense enzyme activities found on the treated fruits, SEM observation showed direct attachment of T. asahii with the fungal hyphae and interfere in their establishment to the fruit surface. Based on these findings, the antagonistic yeast T. asahii strain F001 may be used as a potential natural biological control agent against anthracnose disease in papaya fruit.

Heat stress alters the transcriptome of Debaryomyces hansenii and reduces its biocontrol activity against postharvest gray mold on kiwifruit

Heat stress plays an important role in a postharvest biocontrol system. A basic understanding of heat stress response is crucial to the use of antagonistic yeasts as postharvest biocontrol agents. In the present study, heat stress (42 °C, 20 min) decreased the biocontrol efficacy of the yeast antagonist, Debaryomyces hansenii, against gray mold, caused by Botrytis cinerea, on kiwifruit. RNA-seq was used to conduct a comparative transcriptomic analysis of heat-treated vs. non-heat-treated cultures of D. hansenii. A total of 9775 transcripts comprising 7805 unigenes were obtained from the two treatment groups by de novo assembly. A set of 706 differentially expressed genes (DEGs) were identified between the two treatment groups, comprising 376 up-regulated DEGs and 330 down-regulated DEGs. The identified DEGs were mainly associated with response to stimulus, biological regulation, and developmental process. RT-qPCR analysis was conducted on a subset of eight genes to corroborate the results of the RNA-seq data. The present study provides new information on the molecular response of biocontrol yeasts to heat stress.

Impact of antagonistic yeasts from wine grapes on growth and mycotoxin production by Alternaria alternata.

Alternaria alternata is a major contaminant of wine grapes, meaning a health risk for wine consumers due to the accumulation of toxic metabolites. To develop a successful biofungicide, the effectiveness of epiphytic wine grape yeasts against A. alternata growth and toxin production was assessed in vitro under temperature and aW conditions that simulate those present in the field. The effect of 14 antagonistic yeasts was evaluated on growth and alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA) production by three A. alternata strains in a synthetic medium with composition similar to grape (SN) at three temperatures (15, 25 and 30°C). All Metschnikowia sp. yeast strains evaluated completely prevented A. alternata growth and mycotoxin production at all temperatures in SN medium. Meanwhile, the growth inhibition exerted by Starmerella bacillaris yeast strains was higher at 30°C, followed by 25 and 15°C, being able to show a stimulating or inhibiting effect. Hanseniaspora uvarum yeast strains showed a growth promoting activity higher at 15°C, followed by 25 and 30°C. Even at conditions where A. alternata growth was stimulated by the S. bacillaris and H. uvarum yeasts, high inhibitions of mycotoxin production (AOH, AME and TA) were observed, indicating a complex interaction between growth and mycotoxin production. There is a significant influence of temperature on the effectiveness of biocontrol against A. alternata growth and mycotoxin production. Metschnikowia sp. strains are good candidates to compose a biofungicide against A. alternata. Among the different antagonistic yeasts evaluated, only Metschnikowia sp. strains were equally effective reducing A. alternata growth and mycotoxin at different temperatures underlining the importance of considering environmental factors in the selection of the antagonists.

Meyerozyma guilliermondii SQUCC-33Y suppresses postharvest fruit rot of strawberry caused by Alternaria alternata

Strawberry fruits are vulnerable to infection by a broad range of fungal pathogens before and after harvest. In this study, Alternaria spp. strains associated with fruit rot of strawberry were isolated and characterized and the potential of the antagonistic yeast Meyerozyma guilliermondii strain SQUCC-33Y for the control of fruit rot of strawberry was evaluated. A total of seven isolates of Alternaria (STR2-STR8) were isolated from strawberry fruits showing symptoms of rot. On the basis of internal transcribed spacer (ITS) ribosomal RNA (rRNA) sequences, these fungal isolates were identified as Alternaria alternata. Pathogenicity tests revealed that most of the strains of A. alternata were pathogenic to strawberry. The measurement of disease severity on strawberry fruits revealed significant differences in the virulence between A. alternata strains. M. guilliermondii restricted the growth of all the strains of A. alternata in dual culture assay. Postharvest treatment of strawberry fruits with M. guilliermondii significantly reduced the fruit rot lesion size caused by A. alternata. This antagonistic yeast has the potential for use as a biofungicide for the control of A. alternata-induced postharvest fruit rot of strawberry.

In vitro tolerance to antifungal glycoalkaloids and biofilm forming ability of the antagonistic yeast Meyerozyma guilliermondii strain SQUCC-33Y

Meyerozyma guilliermondii strain SQUCC-33Y is an antagonistic yeast against Alternaria alternata, the tomato fruit rot pathogen. In a previous study, we demonstrated the potential of M. guilliermondii SQUCC-33Y in the control of A. alternata-induced postharvest fruit rot of tomato. In this study, M. guilliermondii SQUCC-33Y was evaluated for its ability to tolerate antifungal glycoalkaloids of tomato and to form biofilm under in vitro conditions. Glycoalkaloids were extracted from immature green tomato fruits. Electrospray ionization-mass spectrometry (ESI-MS) analysis showed the presence of α-tomatine, β-tomatine, tomatidine, lycoperoside A, lycoperoside H, coumaric acid and sinapic acid in the glycoalkaloids extract. In vitro antifungal assays showed that M. guilliermondii SQUCC-33Y and A. alternata were tolerant to glycoalkaloids of tomato, while Rhizoctonia solani was sensitive. M. guilliermondii SQUCC-33Y was able to form biofilm as determined by in vitro microtiter plate assay.

Transcriptome analysis reveals the mechanisms involved in the enhanced antagonistic efficacy of Rhodotorula mucilaginosa induced by chitosan

Our previous study showed that the biocontrol efficacy of Rhodotorula mucilaginosa against postharvest diseases of strawberries can be significantly enhanced by chitosan. Proteome analysis of R. mucilaginosa induced by chitosan has preliminarily explored the molecular mechanisms involved in the enhanced antagonistic efficacy of R. mucilaginosa induced by chitosan. In this study, transcriptome analysis of R. mucilaginosa cultured with and without chitosan was performed, and the activities of CAT, PPO, POD, and SOD were also investigated to further explore the involved mechanisms. The results indicated that the activities of these antioxidant enzymes in R. mucilaginosa were all significantly increased by 0.5 g/100 mL chitosan. Especially, POD activity was about 1.5 - fold higher than the control. Transcriptome and bioinformatic analysis revealed that significant number of genes involved in growth and reproduction, adhesion, energy production, oxidative stress response and other stress response were all induced by chitosan, which resulted in the enhanced antagonistic efficacy of R. mucilaginosa. These results provide a reference for the future study on controlling postharvest disease of fruit and vegetables by antagonist yeast and provide a theoretical basis for the practical application of antagonist yeast.

Analysis of long non-coding RNAs and mRNAs in harvested kiwifruit in response to the yeast antagonist, Wickerhamomyces anomalus

Biological control utilizing antagonistic yeasts is an effective method for controlling postharvest diseases. Long non-coding RNAs (lncRNAs) have been found to be involved in a variety of plant growth and development processes, including those associated with plant disease resistance. In the present study, the yeast antagonist, Wickerhamomyces anomalus, was found to strongly inhibit postharvest blue mold (Penicillium expansum) and gray mold (Botrytis cinerea) decay of kiwifruit. Additionally, lncRNA high-throughput sequencing and bioinformatic analysis was used to identify lncRNAs in W. anomalus-treated wounds in kiwifruit and predict their function based on putative target genes. Our results indicate that lncRNAs may be involved in increasing ethylene (ET), jasmonic acid (JA), abscisic acid (ABA), and auxin (IAA) levels, as well as activating signal transduction pathways that regulate the expression of several transcription factors (WRKY72, WRKY53, JUB1AP2). These transcription factors (TFs) then mediate the expression of downstream, defense-related genes (ZAR1, PAD4, CCR4, NPR4) and the synthesis of secondary metabolites, thus, potentially enhancing disease resistance. Notably, by stimulating the accumulation of antifungal compounds, such as phenols and lignin, disease resistance in kiwifruit was enhanced. Our study provides new information on the mechanism underlying the induction of disease resistance in kiwifruit by W. anomalus, as well as a new disease resistance strategy that can be used to enhance the defense response of fruit to pathogenic fungi.

Assessing hydrothermal treatment and antagonistic yeasts combination for mango anthracnose control

Anthracnose caused by Colletotrichum gloeosporioides is the main post-harvest disease in mango in almost all production areas in the world. Hydrothermal treatment (HT: 46.1 °C for 70 min) and antagonism of yeasts Pichia guilliermondii, Candida oleophila and Candida quercitrusa were evaluated in vitro and in vivo to determine the most appropriate post-harvest management of anthracnose in "Ataulfo" mango. The pathogen C. gloeosporioides and the yeasts were evaluated at concentrations of 105 conidia ml-1 and 108 cells ml-1, respectively. The growth areas of the pathogen subjected to HT and in interaction with the yeasts were evaluated with ImageJ software. Subsequently, the most effective strains and the HT were evaluated in "Ataulfo" mango inoculated with C. gloeosporioides and the severity of the anthracnose was determined. In the in vitro assays, P. guilliermondii strain CDBB-932 was the most effective (18.6%) in controlling pathogen growth, presenting an inhibition halo that the rest of the yeasts did not show. In the in vivo assays, the combination of HT and C. quercitrusa (strain 42) was the most effective (96.8%) in the control of anthracnose. The hydrothermal treatment in combination with yeasts could be implemented preventative control of the postharvest diseases.

Pemanfaatan Khamir Antagonis untuk Memperpanjang Umur Simpan dan Mengendalikan Penyakit Antraknosa Buah Pepaya

Pepaya adalah buah klimakterik yang memiliki umur simpan pendek dan potensi gangguan penyakit antraknosa pada saat tahap pascapanen yang disebabkan oleh patogen Colletotrichum gloeosporioides. Tujuan dari penelitian ini adalah mengkaji keefektifan beberapa spesies khamir antagonis untuk memperpanjang umur simpan dan mengendalikan penyakit antraknosa pada pascapanen buah pepaya Callina. Penelitian ini dilaksanakan di kebun pepaya Desa Kanaga, Kabupaten Lebak, Banten pada November 2018 sampai Juli 2019 dan Laboratorium Pascapanen AGH, IPB pada bulan Maret sampai dengan Juli 2019. Penelitian ini menggunakan rancangan kelompok lengkap teracak dengan perlakuan lima jenis khamir yaitu Cryptococcus albidus Yp, Aureobasidium pullulans Dmg 30 DEP, Rhodotorula minuta Dmg 16 BEP, Candida tropicalis Lm 13 BE, dan Pseudozyma hubeiensis Dmg 18 BEP, dan sebagai pembanding perlakuan fungisida berbahan aktif azoksistrobin serta tanpa perlakuan sebagai kontrol. Hasil penelitian menunjukkan penggunaan khamir Candida tropicalis, Aureobasidium pullulans, dan Cryptococcus albidus dapat memperpanjang umur simpan buah pepaya Callina masing-masing 12.6, 12.4, dan 12.2 hari, lebih lama dibandingkan kontrol yang hanya 7 hari, dan efektif mengendalikan penyakit antraknosa dengan tingkat penekanan secara berturut-turut 58.33%, 54.17%, dan 50.00%, selama penyimpanan. Penggunaan khamir antagonis tidak mempengaruhi mutu fisik dan kimia buah pepaya Callina.
 Kata kunci: buah klimakterik, Colletotrichum gloeosporioides, pascapanen