Biological control of Penicillium italicum, P. digitatum and P. expansum by the predacious yeast Saccharomycopsis schoenii on oranges (original) (raw)
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Efficacy and mode of action of yeast antagonists for control of Penicillium digitatum in oranges
Tropical Plant Pathology
Three yeast antagonists (two strains of Cryptococcus laurentii and one of Candida sake) from orange trees reduced incidence of green mold by 80 to 95% when tested in wounded orange fruits inoculated with Penicillium digitatum and incubated at 7ºC for 30 days. The yeasts inhibited conidial germination of the pathogen, but did not kill the spores. Effectiveness of the three yeasts as antagonists was associated in part with their ability to rapidly colonize wound sites, despite low nutrient availability. Observations suggested that production of extracellular matrix by the yeasts may have facilitated rapid wound colonization. Germination of P. digitatum conidia was significantly inhibited when the pathogen and antagonists were in direct physical contact in a culture suspension. The results supported the view that competition for nutrients is also a mode of action of yeasts against P. digitatum.
Brazilian Journal of Microbiology, 2010
Our investigation of integrated biological control (IBC) started with an assay testing activity of the predacious yeast Saccharomycopsis crataegensis UFMG-DC19.2 against Penicillium digitatum LCP 4354, a very aggressive fungus that causes postharvest decay in oranges. Under unfavourable environmental conditions, the yeast showed a high potential for control (39.9% disease severity reduction) of this fungus. This result was decisive for the next step, in which S. crataegensis was tested in association with sodium bicarbonate salt, a generally regarded as safe (GRAS) substance. The yeast was able to survive at different concentrations of the salt (1%, 2% and 5%), and continued to grow for a week at the wound site, remaining viable at high population for 14 days on the fruit surface. The yeast alone reduced the severity of decay by 41.7% and sodium bicarbonate alone reduced severity of decay by 19.8%, whereas the application of both led to a delay in the development of symptoms from 2 to 10 days. Ingredients of the formulations were not aggressive to fruits since no lesions were produced in control experiments.
Biocontrol activity of antagonistic yeasts against Penicillium expansum on apple
Journal of Plant …, 2003
Penicillium expansum causes severe rots on apple fruit during storage and shelf life. Aiming at the development of new antagonistic yeast active in controlling postharvest pathogens of fruit, several isolates were obtained from fig (Ficus carica) and cactus pear (Opuntia ficus-indica) grown in untreated orchards in Northern Sardinia (Italy). Two yeast strains of Candida guillermondii were selected for their remarkable antagonistic properties against P. expansum on apple. A film-forming strain of Saccharomyces cerevisiae isolated from wine was also included in the experiments. In trials carried out on the cv. Golden Delicious and Fuji, the yeasts applied alone or in the presence of various additives reduced apple rot with up to 100% efficacy. Killed yeast cells and culture filtrates had no biocontrol activity. Addition of different sugars in the apple wound had no detrimental effect on the biocontrol potential of the tested yeasts. Conversely, several nitrates significantly inhibited the antagonistic capability of C. guillermondii, thus suggesting that competition for nitrogen should play a major role in the biocontrol activity of the antagonistic yeast.
Notulae Botanicae Horti Agrobotanici Cluj-Napoca
One of the most important orange fruit diseases is blue mold which cause by Penicillium italicum that is responsible for important economic losses. This study investigated biochemical changes in exo-mesocarp layers of orange fruits related to host- pathogen- yeast interactions. Initial result showed that among eight strains isolated, the most effective antagonist were belonged to two species of Pichia kluyveri (M45) and Rhodotorula mucilaginosa (M61). These isolates were selected for biochemical evaluation. In order to assessment of biochemical changes, the orange fruits were inoculated with 40 µl of yeast cell suspension and after 24 h, the wounds were inoculated with 20 µl of conidial suspension of P. italicum. The analysis of variance showed that all of the measured biochemical characterises were significant in both layers by treatments (yeast isolates; pathogen; yeast isolates + pathogen and control) (P ≤ 0.01), including POD, CAT and β-1, 3-glucanase activities and total p...
Postharvest Biology and Technology, 2019
Twenty five isolates of epiphytic yeasts were isolated from healthy surface of tomato, mango, lemon, orange, grape fruit and green chili and evaluated for their potential against postharvest Penicillium digitatum decay of kinnow fruits. Identification of yeast was confirmed by molecular biology tools. Twenty isolates have shown maximum in-vitro activity against P. digitatum. Eight effective lead isolates were examined for their potential against postharvest natural infection of P. digitatum on kinnow fruit stored for fifteen days at the room temperature (25-30°C). All eight isolates showed least infection of P. digitatum with minimum quality loss as compared to a set of control and positive control (1% K sorbate). Isolates HAB-31 and HAB-53 which showed no postharvest decay of kinnow due to P. digitatum were further evaluated on kinnow by artificially spraying of P. digitatum on kinnow fruits. Yeast treated fruit showed least fruit decay with minimum quality changes as compared to control and positive control set.
Microorganisms, 2020
Fungal rots are one of the main causes of large economic losses and deterioration in the quality and nutrient composition of fruits during the postharvest stage. The yeast Clavispora lusitaniae 146 has previously been shown to efficiently protect lemons from green mold caused by Penicillium digitatum. In this work, the effect of yeast concentration and exposure time on biocontrol efficiency was assessed; the protection of various citrus fruits against P. digitatum by C. lusitaniae 146 was evaluated; the ability of strain 146 to degrade mycotoxin patulin was tested; and the effect of the treatment on the sensory properties of fruits was determined. An efficient protection of lemons was achieved after minimum exposure to a relatively low yeast cell concentration. Apart from lemons, the yeast prevented green mold in grapefruits, mandarins, oranges, and tangerines, implying that it can be used as a broad-range biocontrol agent in citrus. The ability to degrade patulin indicated that str...
ANTAGONIST YEAST: AN EFFICIENT BIOAGENT FOR THE CONTROL OF POST HARVEST PATHOGENS OF FRUITS
Over the years, use of chemical fungicides has been employed as primary method in postharvest disease management of fruits. Although effective, their long-term applications caused disruptions in equilibrium of ecosystems, environmental problems, health hazards to human and animals. Thus, safety of synthetic fungicides in delicate foods like fruits has alarmed legal enforcers and consumers to demand green technology and quality products. Antagonistic organisms have enormous potential to influence agrochemical research. Among them, yeasts are found to be very effective particularly against various post harvest diseases of fruits. Yeasts are a group of fungi which are very efficient in colonizing the wound sites and hence provide protection against various postharvest pathogens through mechanisms like competition for nutrients and space, augmentation of various defense responses in the host and tolerance to reactive oxygen species. Advantages of using of yeasts as biocontrol are controlling environmental conditions during storage suitable for the bioagents as well as the fruits, easy application to the target site and economic viability considering the high cost value of the fruits.
International Journal of Food Microbiology, 2018
Penicillium italicum (Blue mold) is a major postharvest disease of citrus. An alternative to controlling the disease is through the use of yeasts. The purpose of the present study was to screen effective yeast antagonists against P. italicum, isolated from soil, leaves, flowers, and citrus fruits, to assess the action mechanisms of the yeast isolates that were demonstrated to be effective for biocontrol, and to identify the most effective yeast isolates for the biocontrol of blue mold. The in vitro assays showed that six yeast strains inhibited up to 90% of the pathogen's mycelial growth. In vivo assays, evaluating the incidence of blue mold on sweet oranges, the strains ACBL-04, ACBL-05, ACBL-10 and ACBL-11 were effective, demonstrating the potential for the blue mold control when preventively applied, whereas the ACBL-08 strain showed a high potential to preventive and curative applications. Additional studies on the modes of action of these yeast strains showed that most of the evaluated yeast strains did not produce antifungal substances, in sufficient quantities to inhibit the pathogen growth. Competition for nutrients was not a biocontrol strategy used by the yeast strains. The 'killer' activity might be the main action mechanism involved in P. italicum biocontrol. This study indicated that the multiple modes of action against the pathogen presented by yeasts may explain why these strains provided P. italicum control under in vitro and in vivo conditions. However, further studies in future might be able to elucidate the 'killer' activity and its interaction with pathogen cells and the bioproduct production using Candida stellimalicola strains for control postharvest diseases.
Microorganisms
To select antagonistic yeasts for the control of fruit rot caused by Lasiodiplodia theobromae and anthracnose caused by Colletotrichum gloeosporioides in postharvest mango fruit, 307 yeast strains isolated from plant leaves were evaluated for their antagonistic activities against these two fungal pathogens in vitro. Torulaspora indica DMKU-RP31, T. indica DMKU-RP35 and Pseudozyma hubeiensis YE-21 were found to inhibit the growth of L. theobromae whereas only Papiliotrema aspenensis DMKU-SP67 inhibited the growth of C. gloeosporioides. Antagonistic mechanisms of these four antagonistic yeasts in vitro consisted of the production of antifungal volatile organic compounds (VOCs), biofilm formation and siderophore production. T. indica DMKU-RP35 was the most effective strain in controlling fruit rot on postharvest mango fruits. Its action was comparable to that of the fungicide, benomyl, reducing the disease severity by 82.4%, whereas benomyl revealed 87.5% reduction. P. aspenensis DMKU-...