Potential biocontrol activity of a strain of Pichia guilliermondii against grey mold of apples and its possible modes of action (original) (raw)
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Biological Control, 2011
The interactions of Penicillium italicum, which causes blue mould, and antagonistic yeast Pichia guilliermondii strain Z1 were examined in controlled environments, to determine the influence of relative humidity (RH) (45%, 75%, 85%, 98%, and 100%) and temperature (T) (5, 10, 15, 20, and 25°C). All main effects and interactions were significant (P 6 0.05), with the exception of interactions RHÂT and strain Z1 (BCA)ÂRHÂT. In the pathogen control, the lesion diameter of blue mould developed under all environmental conditions but was the largest at a RH range between 98% and 100%, independent of the temperature. The efficacy of strain Z1 appeared to be independent of the environment and reduced disease incidence by more than 85% in all environmental conditions. Rapid colonization of the antagonistic yeast strain Z1 on citrus wounded sites was recorded during the first week at 5°C. Colonization then stabilized at ±6.9 Â 10 6 CFU/ml for 30 days. This indicates that P. guilliermondii is able to adapt itself and colonize the wound sites prior to the arrival of the pathogen, displaying greater efficiency than when colonizing wounds after pathogen. The antagonist was capable of growing in low concentrations of orange juice (0.1-5%), with greatest growth at 5%. Applying strain Z1 (1 Â 10 8 CFU/ml) as a formulated product significantly reduced the incidence of infected fruits and the percentage of infected wounds relative to the pathogen control. Disease control with formulated product (45%) was slightly lower than that obtained with thiabendazole (20%) or strain Z1 culturable cells (25%). These results suggest that strain Z1 may be a useful BCA for control of blue mould under varying environmental conditions, and control may be enhanced by combining with other eco-friendly post-harvest treatments or improved formulation.
Italian Journal of Food Safety, 2014
In previous studies it was shown that Pichia guilliermondii strain Z1, isolated from healthy Moroccan citrus Valencia-Late oranges, was effective against Penicillium italicum. Here the effectiveness of strain Z1 was assessed against Penicillium digitatum, the causal agent of green mould, under different temperature (5-25°C) and relative humidity (RH) (45-100%) regimes for its reliable and largescale application in packinghouse. All main effects and interactions were significant (P<0.0001). In the pathogen control, the largest lesion diameter was at an RH range between 98 and 100%, regardless of the incubation temperature. The efficacy of strain Z1 was not dependent on the environment and reduced disease incidence by >80%. Its applications as a formulated product significantly reduced the incidence of infected fruit (55%) and the percentage of infected wounds (47%) compared to the only pathogen control treatment. However, disease control with formulated product was significantly less than that obtained with thiabendazole (30%) or strain Z1 culturable cells (35%). These results highlight that strain Z1 is an effective biological control agent for control of green mould under varying environmental conditions, and control may be optimized by combining its use with other environmentally-safe post-harvest treatments or improved formulation. This work is licensed under a Creative Commons Attribution 3.0 License (by-nc 3.0). ©Copyright R.
In the present study, two yeast antagonists, Cryptococcus laurentii (strain 317) and Candida ciferrii (strain 283) isolated from the surface of healthy apples, controlled blue mold of apple caused by Penicillium expansum. Both antagonists reduced the incidence of blue mold by 80% at 25°C. At 5°C C. ciferrii (strain 283) maintained the efficacy of disease control, but C. laurentii (strain 317) only reduced disease incidence by 50%. Moreover C. ciferrii (strain 283) exhibited significant protection at lower concentrations than C. laurentii (strain 317). The population of both strains increased in wounds of apples at 25 and 5°C, and both strains maintained viable over a period of 35 days at 5°C. Nutrient competition into wounds appeared to be the principal mode of action of these antagonists. Nitrogen rather than carbon appeared to be the limiting factor to both the antagonists and the pathogen. Further research will explore commercial potential of these antagonists and the possibility of enhancing biocontrol efficacy by using mixtures of antagonists or addtives such as calcium chloride or deoxyglucose.
European Journal of Plant Pathology, 2009
The yeast Pichia anomala strain K was selected in Belgium from the apple surface for its antagonistic activity against post-harvest diseases of apples. The efficacy of this strain against P. expansum was evaluated in the laboratory in three scenarios designed to mimic practical conditions, with different periods of incubation between biological treatment, wounding of fruit surface, and pathogen inoculation. Higher protection levels and higher final yeast densities were obtained when the applied initial concentration was 1 × 108 cfu ml−1 than when it was only 1 × 105 cfu ml−1. The protection level correlated positively with the yeast density determined in wounds and was influenced by apple surface wetness. In orchard trials spanning two successive years, biological treatment against P. expansum, based on a powder of P. anomala strain K (1 × 107 cfu ml−1), β-1,3-glucans (YGT 2 g l−1), and CaCl2.2H20 (20 g l−1), was applied to apples pre- or post-harvest under practical conditions and its effect compared with standard chemical treatments. The first year, the highest reduction (95.2%) against blue decay was obtained by means of four successive fungicide treatments and the next-highest level (87.6%) with pre-harvest high-volume spraying of the three-component mixture 12 days before harvest. The second year, the best results were obtained with post-harvest Sumico (carbendazim 25% and diethofencarb 25%) treatment and post-harvest biological treatment, both by dipping the apples, 88.3 and 56.3% respectively. A density threshold of 1 × 104 cfu cm−2 of strain K on the apple surface seemed to be required just after harvest for high protective activity, whatever the method and time of application. In the case of pre-harvest biological treatments, variations in meteorological conditions between the 2 years may have considerably affected strain K population density and its efficacies.
Characterization of biocontrol activity of two yeast strains from Uruguay against blue mold of apple
Postharvest Biology and Technology, 2002
Six yeast strains isolated from the surface of pear fruits were evaluated for their ability to control postharvest blue mold (caused by Penicillium expansum) on Golden Delicious apple fruits. All strains significantly reduced blue mold incidence and severity when applied simultaneously with the pathogen. Cryptococcus infirmo-miniatus strain YY6 and Cryptococcus laurentii strain HRA5 were the most effective, and populations in apple wounds increased approximately 1.2 log units within 10 days at 0°C and approximately 1.4 log units in 2 days at 5, 10, or 20°C. Control of blue mold by these two yeasts alone or in combination with a low dose of thiabendazole (15 mg/ml) was tested at 5, 10, and 20°C. Yeasts combined with thiabendazole controlled the disease significantly better at all temperatures (except at 10°C during 1994) than the low dose of thiabendazole alone, and the control was comparable to that achieved using a commercially recommended high dose of thiabendazole (525 mg/ml). C. infirmominiatus controlled disease incidence better than C. laurentii at 5, 10, and 20°C during 1993 and 1994. On sweet cherry, C. infirmo-miniatus or C. laurentii combined with a low dose (20 mg/ml) of iprodione controlled brown rot caused by Monilinia fructicola as did a high dose (1175 mg/ml) of iprodione. r 1996 Academic Press, Inc.
Control of Mould Spoilage on Apples Using Yeasts as Biological Control Agents
Polish Journal of Food and Nutrition Sciences
Considerable quantities of fruit are lost during pre-and post-harvest stages due to mould spoilage. The aim of this study was to evaluate the antagonistic effect of selected yeasts against spoilage mould Botrytis cinerea, Penicillium expansum and Alternaria alstroemeriae. One hundred and four yeast isolates were screened for antagonistic activity against B. cinerea, P. expansum and A. alstroemeriae using radial inhibition, dual and mouth-to-mouth plate assays. Sixty-seven out of 104 yeasts showed growth inhibition activity against P. expansum, while 36 yeasts inhibited B. cinerea, 47 yeasts inhibited A. alstroemeriae, but only 22 yeasts displayed inhibition activity against all three moulds. Candida pyralidae Y63, Meyerozyma guilliermondii Y88 and Zygoascus hellenicus Y89 had the highest inhibition activity against all three moulds, when mode of inhibition was due to direct contact. Volatile organic compounds produced by Pichia kluyveri Y64, C. pyralidae Y63 and M. guilliermondii Y88 demonstrated the highest growth inhibition against all three moulds. These yeasts were also evaluated against all three moulds on apples. P. kluyveri Y64 displayed 100%, 57% and 26% growth inhibition against A. alstroemeriae, B. cinerea and P. expansum, respectively, on apples and performed slightly better than a commercial fungicide against B. cinerea and P. expansum. While M. guillermondii Y88 showed 100%, 60% and 18% inhibition on apples against A. alstroemeriae, B. cinerea and P. expansum, respectively. P. kluyveri Y64 and M. guilliermondii Y88 demonstrated potential as biofungicides and warrant further investigation.
Biological Control of Gray Mold in Pears by Antagonistic Bacteria
Biological Control, 1996
The possibility of employing antagonistic bacteria for postharvest control of gray mold on pear was studied. Approximately 175 strains of bacteria were isolated from beneath the skin of various fruits and vegetables and 14 of these possessed high levels of antagonistic properties. They significantly reduced gray mold in cv Conference pear artificially inoculated with Botrytis cinerea and stored at 20°C for at least 9 days. Two strains, 3PPE (Bacillus pumilus) and 2TOE (Bacillus amyloliquefaciens), were particularly active. They did not produce antibiotic substances and their application was compatible with iprodione-based antifungal treatments. The bacterial antagonist mixed with the fungicide at 50 ppm a.i. resulted in a greater control of the pathogen compared to the single ingredient. Holding bacteria-treated fruits at 20°C for 24 h before cold storage improved the efficacy of the bacteria against gray mold.
Applied and environmental microbiology, 1994
The glucose analog, 2-deoxy-d-glucose (2-DOG) enhanced biocontrol of blue mold (caused by Penicillium expansum), the most important postharvest disease of apples and pears. 2-DOG strongly inhibited P. expansum, and of the two antagonists investigated, Pseudomonas syringae was resistant to 2-DOG at 10 mg/ml whereas Sporobolomyces roseus was susceptible. A mutant of S. roseus resistant to 2-DOG was developed. Addition of 2-DOG at 4 mg/ml allowed more than a 10-fold reduction in the concentration of the antagonists applied to fruits without diminishing control. This effect was still apparent at an inoculum of 5 x 10 conidia of P. expansum per ml, which greatly exceeds concentrations found under normal commercial conditions. The effect of 2-DOG on biocontrol was stronger on apples than on pears. 2-DOG had no effect on populations of the antagonists, which increased greatly in wounds on apples and pears. The reduction in the concentration of the antagonists needed for control may improve...
Biological Control, 1996
Twenty-eight yeasts isolated from habitats other than apple were screened for their potential to protect wounds of Golden Delicious apples during storage from gray mold caused by Botrytis cinerea. All isolates reduced (P F 0.05) decay severity and 23 reduced decay incidence after 7 days at 22-24°C when applied at 5 3 10 6 CFU per wound 1-2 h earlier than 8 3 10 3 conidia of B. cinerea (P F 0.05). When selected isolates were tested at 5 3 10 5 CFU per wound on apples stored for 30 days at 4°C, Cryptococcus humicola NRRL Y1266, Filobasidium floriforme NRRL Y7454, and Rhodosporidium toruloides NRRL Y1091, previously unreported gray mold antagonists, reduced both incidence and decay severity as well as chlorothalonil and Sporobolomyces roseus FS-43-238, a reported biocontrol agent. Experiments at 22-24°C indicated that, with the exception of R. toruloides, protection generally required yeast inoculation into wounds before conidia. Nine yeasts protected wounds at 5 3 10 6 CFU per wound, whereas only three of nine were effective at 5 3 10 2 CFU per wound, a density calculated to be too low to preemptively carpet the wound, even though selected yeasts increased at least one log unit in the first 24 h following inoculation into wounds. In vitro utilization of 14 Clabeled sucrose by the yeasts was greater than that by the conidia after 12-48 h incubation, supporting nutrient competition as a mechanism of antagonism. Cellfree, dilute sucrose solutions that were preincubated with effective biocontrol yeasts for 24 h significantly inhibited conidium germination; however, a solution preincubated with a sucrose-utilizing but less effective yeast did not. Results suggest that nutrient competition may have played a significant role in biocontrol, but the contribution of preemptive physical exclusion and antifungal metabolites to a complex biocontrol process cannot be dismissed. r