Whole-genome comparisons of Penicillium spp. reveals secondary metabolic gene clusters and candidate genes associated with fungal aggressiveness during apple fruit decay

Blue mold is a postharvest rot of pomaceous fruits caused by Penicillium expansum and a number of other Penicillium species. The genome of the highly aggressive P. expansum strain R19 was re-sequenced and analyzed together with the genome of the less aggressive P. solitum strain RS1. Whole genome scale similarities and differences were examined. A phylogenetic analysis of P. expansum, P. solitum, and several closely related Penicillium species revealed that the two pathogens isolated from decayed apple with blue mold symptoms are not each other’s closest relatives. Among a total of 10,560 and 10,672 protein coding sequences respectively, a comparative genomics analysis revealed 41 genes in P. expansum R19 and 43 genes in P. solitum RS1 that are unique to these two species. These genes may be associated with pome fruit–fungal interactions, subsequent decay processes, and mycotoxin accumulation. An intact patulin gene cluster consisting of 15 biosynthetic genes was identified in the patulin producing P. expansum strain R19, while only a remnant, seven-gene cluster was identified in the patulin-deficient P. solitum strain. However, P. solitum contained a large number of additional secondary metabolite gene clusters, indicating that this species has the potential capacity to produce an array of known as well as not-yet-identified products of possible toxicological or biotechnological interest.

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Whole-genome comparisons of Penicillium spp. reveals secondary metabolic gene clusters and candidate genes associated with fungal aggressiveness during apple fruit decay

10.7287/peerj.preprints.27430v1 ◽

2018 ◽

Author(s):

Guangxi Wu ◽

Wayne M Jurick II ◽

Franz J Lichtner ◽

Hui Peng ◽

Guohua Yin ◽

...

Keyword(s):

Gene Cluster ◽

Gene Clusters ◽

Apple Fruit ◽

Penicillium Expansum ◽

Whole Genome ◽

Blue Mold ◽

Pome Fruit ◽

Fruit Decay ◽

Postharvest Rot ◽

Fungal Interactions

Blue mold is a postharvest rot of pomaceous fruits caused by Penicillium expansum and a number of other Penicillium species. The genome of the highly aggressive P. expansum strain R19 was re-sequenced and analyzed together with the genome of the less aggressive P. solitum strain RS1. Whole genome scale similarities and differences were examined. A phylogenetic analysis of P. expansum, P. solitum, and several closely related Penicillium species revealed that the two pathogens isolated from decayed apple with blue mold symptoms are not each other’s closest relatives. Among a total of 10,560 and 10,672 protein coding sequences respectively, a comparative genomics analysis revealed 41 genes in P. expansum R19 and 43 genes in P. solitum RS1 that are unique to these two species. These genes may be associated with pome fruit–fungal interactions, subsequent decay processes, and mycotoxin accumulation. An intact patulin gene cluster consisting of 15 biosynthetic genes was identified in the patulin producing P. expansum strain R19, while only a remnant, seven-gene cluster was identified in the patulin-deficient P. solitum strain. However, P. solitum contained a large number of additional secondary metabolite gene clusters indicating that this species has the potential capacity to produce an array of known, as well as not-yet-identified products, of possible toxicological or biotechnological interest.

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Whole-genome comparisons of Penicillium spp. reveals secondary metabolic gene clusters and candidate genes associated with fungal aggressiveness during apple fruit decay

10.7287/peerj.preprints.27430 ◽

2018 ◽

Author(s):

Guangxi Wu ◽

Wayne M Jurick II ◽

Franz J Lichtner ◽

Hui Peng ◽

Guohua Yin ◽

...

Keyword(s):

Gene Cluster ◽

Gene Clusters ◽

Apple Fruit ◽

Penicillium Expansum ◽

Whole Genome ◽

Blue Mold ◽

Pome Fruit ◽

Fruit Decay ◽

Postharvest Rot ◽

Fungal Interactions

Blue mold is a postharvest rot of pomaceous fruits caused by Penicillium expansum and a number of other Penicillium species. The genome of the highly aggressive P. expansum strain R19 was re-sequenced and analyzed together with the genome of the less aggressive P. solitum strain RS1. Whole genome scale similarities and differences were examined. A phylogenetic analysis of P. expansum, P. solitum, and several closely related Penicillium species revealed that the two pathogens isolated from decayed apple with blue mold symptoms are not each other’s closest relatives. Among a total of 10,560 and 10,672 protein coding sequences respectively, a comparative genomics analysis revealed 41 genes in P. expansum R19 and 43 genes in P. solitum RS1 that are unique to these two species. These genes may be associated with pome fruit–fungal interactions, subsequent decay processes, and mycotoxin accumulation. An intact patulin gene cluster consisting of 15 biosynthetic genes was identified in the patulin producing P. expansum strain R19, while only a remnant, seven-gene cluster was identified in the patulin-deficient P. solitum strain. However, P. solitum contained a large number of additional secondary metabolite gene clusters indicating that this species has the potential capacity to produce an array of known, as well as not-yet-identified products, of possible toxicological or biotechnological interest.

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Characterization of Fludioxonil-Resistant and Pyrimethanil-Resistant Phenotypes of Penicillium expansum from Apple

Phytopathology ◽

10.1094/phyto-98-4-0427 ◽

2008 ◽

Vol 98 (4) ◽

pp. 427-435 ◽

Cited By ~ 55

Author(s):

H. X. Li ◽

C. L. Xiao

Keyword(s):

Osmotic Stress ◽

The United States ◽

Apple Fruit ◽

Penicillium Expansum ◽

Postharvest Disease ◽

Wild Type ◽

Blue Mold ◽

Pome Fruit ◽

Development Of Resistance ◽

Resistant Mutants

Penicillium expansum is the primary cause of blue mold, a major postharvest disease of apple. Fludioxonil and pyrimethanil are two newly registered postharvest fungicides for pome fruit in the United States. To evaluate the potential risk of resistance development in P. expansum to the new postharvest fungicides, one isolate of each of thiabendazole-resistant (TBZ-R) and -sensitive (TBZ-S) P. expansum was exposed to UV radiation to generate fungicide-resistant mutants. Four fludioxonil highly-resistant mutants (EC50 > 1,000 μg/ml) and four pyrimethanil-resistant mutants (EC50 > 10 μg/ml) were tested for sensitivities to thiabendazole, fludioxonil, and pyrimethanil, and fitness parameters including mycelial growth, sporulation on potato dextrose agar (PDA), sensitivity to osmotic stress, and pathogenicity and sporulation on apple fruit. The stability of resistance of the mutants was tested on PDA and apple fruit. Efficacy of the three fungicides to control blue mold incited by the mutants was evaluated on apple fruit. Six fungicide-resistant phenotypes were identified among the parental wild-type isolates and their mutants based upon their resistance levels. All four fludioxonil highly-resistant mutants were sensitive to pyrimethanil and retained the same phenotypes of resistance to TBZ as the parental isolates. All four pyrimethanil-resistant mutants had a low level of resistance to fludioxonil with a resistance factor >15. The two pyrimethanil-resistant mutants derived from a TBZ-S isolate became resistant to TBZ at 5 μg/ml. After 20 successive generations on PDA and four generations on apple fruit, the mutants retained the same phenotypes as the original generations. All mutants were pathogenic on apple fruit at both 0 and 20°C, but fludioxonil highly-resistant mutants were less virulent and produced fewer conidia on apple fruit than pyrimethanil-resistant mutants and their parental wild-type isolates. Compared with the parental isolates, all four fludioxonil highly-resistant mutants had an increased sensitivity to osmotic stress on PDA amended with NaCl, while the pyrimethanil-resistant mutants did not. Pyrimethanil was effective against blue mold caused by fludioxonil-resistant mutants at both 0 and 20°C. Pyrimethanil and fludioxonil reduced blue mold incited by pyrimethanil-resistant mutants during 12-week storage at 0°C but were not effective at 20°C. TBZ was not effective against pyrimethanil-resistant mutants derived from TBZ-S wild-type isolates at room temperature but provided some control at 0°C. The results indicate that: (i) a fitness cost was associated with fludioxonil highly resistant mutants of P. expansum in both saprophytic and pathogenic phases of the pathogen but not pyrimethanil-resistant mutants; (ii) pyrimethanil possessed a higher risk than fludioxonil in the development of resistance in P. expansum; and (iii) triple resistance to the three apple-postharvest fungicides could emerge and become a practical problem if resistance to pyrimethanil develops in P. expansum populations.

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Effects of Sporidiobolus pararoseus Y16 on Postharvest Blue Mold Decay and the Defense Response of Apples

Journal of Food Quality ◽

10.1155/2018/6731762 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9 ◽

Cited By ~ 8

Author(s):

Lina Zhao ◽

Yiwen Sun ◽

Dongbiao Yang ◽

Jun Li ◽

Xiangyu Gu ◽

...

Keyword(s):

Defense Response ◽

Apple Fruit ◽

Penicillium Expansum ◽

Tube Length ◽

Blue Mold ◽

Expression Levels ◽

Germ Tube Length ◽

Fruit Decay ◽

Sporidiobolus Pararoseus

The efficacy of Sporidiobolus pararoseus Y16 in controlling postharvest blue mold caused by Penicillium expansum on apples and the defense response involved were evaluated. The results suggested that the decay incidence of blue mold of apples treated by S. pararoseus Y16 was significantly reduced compared with the control. In vitro testing indicated that germination of spores and germ tube length of P. expansum were markedly inhibited by S. pararoseus Y16. Meanwhile, polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia lyase (PAL), and catalase (CAT) activities and several pathogenesis-related (PR) gene expression levels (including PR3, PR4, PR5, and PR9) were determined. In apples, the activities of PPO, POD, CAT, and PAL were significantly induced by S. pararoseus Y16 treatment compared with the control fruits. The relative expression levels of PR3 and PR4 were significantly induced at 4 and 6 d, while PR5 was significantly induced at 4 and 6 d and PR9 was significantly induced at 4 d. Therefore, the reduction in apple fruit decay by S. pararoseus Y16 treatment could be related to the increased activities of related enzymes and proteins involved in the defense against pathogens, which suggest that S. pararoseus Y16 is a potential antagonistic yeast.

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Genomic Analyses of Penicillium Species Have Revealed Patulin and Citrinin Gene Clusters and Novel Loci Involved in Oxylipin Production

Journal of Fungi ◽

10.3390/jof7090743 ◽

2021 ◽

Vol 7 (9) ◽

pp. 743

Author(s):

Guohua Yin ◽

Hui Zhao ◽

Kayla K. Pennerman ◽

Wayne M. Jurick ◽

Maojie Fu ◽

...

Keyword(s):

New Jersey ◽

Gene Cluster ◽

Gene Clusters ◽

Apple Fruit ◽

Hurricane Sandy ◽

Blue Mold ◽

Penicillium Species ◽

Genomic Analyses ◽

Penicillium Spp ◽

Complete Genomic

Blue mold of apple is caused by several different Penicillium species, among which P. expansum and P. solitum are the most frequently isolated. P. expansum is the most aggressive species, and P. solitum is very weak when infecting apple fruit during storage. In this study, we report complete genomic analyses of three different Penicillium species: P. expansum R21 and P. crustosum NJ1, isolated from stored apple fruit; and P. maximae 113, isolated in 2013 from a flooded home in New Jersey, USA, in the aftermath of Hurricane Sandy. Patulin and citrinin gene cluster analyses explained the lack of patulin production in NJ1 compared to R21 and lack of citrinin production in all three strains. A Drosophila bioassay demonstrated that volatiles emitted by P. solitum SA and P. polonicum RS1 were more toxic than those from P. expansum and P. crustosum strains (R27, R11, R21, G10, and R19). The toxicity was hypothesized to be related to production of eight-carbon oxylipins. Putative lipoxygenase genes were identified in P. expansum and P. maximae strains, but not in P. crustosum. Our data will provide a better understanding of Penicillium spp. complex secondary metabolic capabilities, especially concerning the genetic bases of mycotoxins and toxic VOCs.

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Indole-3-Acetic Acid Improves Postharvest Biological Control of Blue Mold Rot of Apple by Cryptococcus laurentii

Phytopathology ◽

10.1094/phyto-99-3-0258 ◽

2009 ◽

Vol 99 (3) ◽

pp. 258-264 ◽

Cited By ~ 22

Author(s):

Ting Yu ◽

Jishuang Chen ◽

Huangping Lu ◽

Xiaodong Zheng

Keyword(s):

Acetic Acid ◽

Apple Fruit ◽

Natural Resistance ◽

Penicillium Expansum ◽

Cryptococcus Laurentii ◽

Blue Mold ◽

Biocontrol Efficacy ◽

Indole 3 Acetic Acid

Cryptococcus laurentii is a well-known postharvest biocontrol yeast; however, it cannot provide satisfactory levels of decay control when used alone. Here, we evaluated the effects of indole-3-acetic acid (IAA), a plant growth regulator, on the biocontrol efficacy of the yeast antagonist C. laurentii against blue mold rot caused by Penicillium expansum in apple fruit. Results showed that the addition of IAA at 20 μg/ml to suspensions of C. laurentii greatly enhanced inhibition of mold rot in apple wounds compared with that observed with C. laurentii alone. The addition of IAA at 20 μg/ml or lower did not influence the population growth of C. laurentii in wounds, but adverse effects were seen on C. laurentii when the concentration of IAA was increased to 200 μg/ml or above in vitro and in vivo. P. expansum infection in apple wounds was not inhibited when the pathogen was inoculated into the fruit wounds within 2 h after application of IAA; however, infection was reduced when inoculated more than 12 h after IAA application. Treatment of wounds with IAA at 20 μg/ml 24 h before pathogen inoculation resulted in significant inhibition of P. expansum spore germination and host infection. Application of IAA at 20 μg/ml also reduced P. expansum infection when it was applied 48 h before pathogen inoculation in the intact fruit. Thus, IAA could reinforce the biocontrol efficacy of C. laurentii in inhibiting blue mold of apple fruit by induction of the natural resistance of the fruit.

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Occurrence and Phenotypes of Pyrimethanil Resistance in Penicillium expansum from Apple in Washington State

Plant Disease ◽

10.1094/pdis-07-13-0721-re ◽

2014 ◽

Vol 98 (7) ◽

pp. 924-928 ◽

Cited By ~ 14

Author(s):

R. Caiazzo ◽

Y. K. Kim ◽

C. L. Xiao

Keyword(s):

High Resistance ◽

Apple Fruit ◽

Washington State ◽

Penicillium Expansum ◽

Small Scale ◽

Blue Mold ◽

Resistance Phenotype ◽

Low Resistance

Penicillium expansum is the cause of blue mold in stored apple fruit. In 2010–11, 779 isolates of P. expansum were collected from decayed apple fruit from five packinghouses, tested for resistance to the postharvest fungicide pyrimethanil, and phenotyped based on the level of resistance. In 2010, 85 and 7% of the isolates were resistant to pyrimethanil in packinghouse A and B, respectively, where pyrimethanil had been used for four to five consecutive years. In 2011, pyrimethanil or fludioxonil was used in packinghouse A, and 96% of the isolates from the fruit treated with pyrimethanil were resistant but only 4% of the isolates from the fruit treated with fludioxonil were resistant to pyrimethanil, suggesting that fungicide rotation substantially reduced the frequency of pyrimethanil resistance. No pyrimethanil-resistant isolates were detected in 2010 in the three other packinghouses where the fungicide had been used recently on a small scale. However 1.8% of the isolates from one of the three packinghouses in 2011 were resistant to pyrimethanil. A significantly higher percentage of thiabendazole-resistant than thiabendazole-sensitive isolates were resistant to pyrimethanil. Of the pyrimethanil-resistant isolates, 37 to 52, 4 to 5, and 44 to 58% were phenotyped as having low, moderate, and high resistance to pyrimethanil, respectively. Fludioxonil effectively controlled pyrimethanil-resistant phenotypes on apple fruit but pyrimethanil failed to control phenotypes with moderate or high resistance to pyrimethanil and only partially controlled the low-resistance phenotype.

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Pre- and Post-harvest Harpin Treatments of Apples Induce Resistance to Blue Mold

Plant Disease ◽

10.1094/pdis.2003.87.1.39 ◽

2003 ◽

Vol 87 (1) ◽

pp. 39-44 ◽

Cited By ~ 43

Author(s):

Guy de Capdeville ◽

Steven V. Beer ◽

Christopher B. Watkins ◽

Charles L. Wilson ◽

Luís O. Tedeschi ◽

...

Keyword(s):

Apple Fruit ◽

Penicillium Expansum ◽

Blue Mold ◽

Apple Trees ◽

Inoculum Concentration ◽

Commercial Formulation ◽

Disease Progress ◽

Promising Strategy ◽

Cold Room ◽

Induce Resistance

Harpin was studied for its ability to induce resistance in apple fruit to blue mold caused by Penicillium expansum after harvest. Red Delicious fruit were harvested and sprayed with harpin at 0, 40, 80, and 160 mg/liter applied as a commercial formulation. At 48, 96, and 144 h after treatment, fruit were wound inoculated with spore suspensions of P. expansum at 103, 5 × 103, or 104 spores/ml. The diameters of the resulting lesions were directly proportional to the inoculum concentration. Fewer fruit treated with harpin became infected relative to the controls, and disease progress was considerably reduced. In a second experiment, apple trees of the cultivars McIntosh, Empire, and Red Delicious were sprayed with different concentrations of harpin 8 or 4 days before harvest. Fruit were harvested, wounded, inoculated with the fungus, and stored in a commercial cold room. Fewer fruit treated with harpin became infected compared with the controls. Greater control resulted from the higher concentrations of harpin, but no difference in control occurred as a function of interval between the spray time and harvest. Spraying apple trees with harpin a few days before harvest is a promising strategy for reducing blue mold decay in storage.

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Fumigation of Fruit with Short-Chain Organic Acids to Reduce the Potential of Postharvest Decay

Plant Disease ◽

10.1094/pdis.1998.82.6.689 ◽

1998 ◽

Vol 82 (6) ◽

pp. 689-693 ◽

Cited By ~ 40

Author(s):

P. L. Sholberg

Keyword(s):

Formic Acid ◽

Fungal Pathogens ◽

Citrus Fruit ◽

Penicillium Expansum ◽

Monilinia Fructicola ◽

Rhizopus Stolonifer ◽

Pome Fruit ◽

Fruit Peel ◽

Postharvest Decay ◽

Fruit Decay

Vapors of acetic (1.9 or 2.5 μl/liter), formic (1.2 μl/liter), and propionic (2.5 μl/liter) acids were tested for postharvest decay control on 8 cherry, 14 pome, and 3 citrus fruit cultivars. Surfacesterilized fruit were inoculated with known fungal pathogens by drying 20-μl drops of spore suspension on marked locations on each fruit, placing at 10°C to equilibrate for approximately 24 h, and fumigating by evaporating the above acids in 12.7-liter airtight fumigation chambers for 30 min. Immediately after fumigation, the fruit were removed, aerated, aseptically injured, and placed at 20°C until decay occurred. All three fumigants controlled Monilinia fructicola, Penicillium expansum, and Rhizopus stolonifer on cherry. Formic acid increased fruit pitting on six of eight cultivars and was the only organic acid to increase blackening of cherry stems when compared to the control. Decay of pome fruit caused by P. expansum was reduced from 98% to 16, 4, or 8% by acetic, formic, and propionic acids, respectively, without injury to the fruit. Decay of citrus fruit by P. digitatum was reduced from 86 to 11% by all three acids, although browning of the fruit peel was observed on grapefruit and oranges fumigated with formic acid.

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Fumigation of Stored Pome Fruit with Hexanal Reduces Blue and Gray Mold Decay

HortScience ◽

10.21273/hortsci.42.3.611 ◽

2007 ◽

Vol 42 (3) ◽

pp. 611-616 ◽

Cited By ~ 18

Author(s):

Peter L. Sholberg ◽

Paul Randall

Keyword(s):

Titratable Acidity ◽

Polynomial Equation ◽

Gray Mold ◽

Soluble Solids ◽

Penicillium Expansum ◽

Effective Control ◽

Blue Mold ◽

Pome Fruit ◽

Third Order ◽

Apple Slices

Stored apples and pears are subject to blue and gray mold decay incited by Penicillium expansum and Botrytis cinerea respectively. Hexanal, a C6 carbon aldehyde, used as a vapor provided effective control of both blue and gray molds in laboratory experiments on apple slices. A preliminary trial with ‘Anjou’ pears in bins showed that hexanal was not corrosive and could reduce gray mold in pears stored for 7 months. However details on the correct procedure for fumigating pome fruit were lacking, and further studies were needed to develop a reliable fumigation strategy. In trials with inoculated fruit, hexanal inactivated conidia of B. cinerea contaminating the pear surface when used at a rate of 2 mg·L−1 for 24 hours or 4 mg·L−1 for 18 hours. It was less effective on ‘Gala’ apples inoculated with conidia of P. expansum, but reduced blue mold decay to low levels at 15 ºC. On the other hand, hexanal increased gray and blue molds when used after wounds were made in inoculated fruit. The use of a preharvest treatment with cyprodinil (0.62 g·L−1) reduced both blue and gray molds in wounds with or without hexanal fumigation. Thus a strategy for controlling postharvest decay was developed by which fruit were treated 2 weeks before harvest with cyprodinil, followed by fumigation with hexanal immediately after harvest. The use of this strategy on ‘Anjou’ pears produced the highest number of mold-free fruit in 2003 and the least amount of gray and blue mold decay in 2003 and 2004 on pears stored for 4 months. Wounded apples only developed 1% rot compared with 10% in the control, indicating that hexanal fumigation of stored apples reduced contamination. Monitoring hexanal during fumigation showed that hexanal concentration declined slowly over a 24-hour period and could accurately be described by a third-order polynomial equation. Hexanal fumigation at low rates (2–3 mg·L−1) was not phytotoxic and improved aroma in ‘Anjou’ pears and ‘Gala’ apples with no harmful effects on apple or pear firmness, pH, titratable acidity, or soluble solids.

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