First report of fusarium avenaceum causing wet core rot of ‘elstar’ apples in the Netherlands

M. Wenneker, K.T.K. Pham, M.E.C. Lemmers, Fred de Boer, Arie van der Lans, Paul van Leeuwen, T.C. Hollinger, B.P.H.J. Thomma

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Apple (Malus domestica) is an important fruit crop in the Netherlands. ‘Elstar’, the main cultivar, occupies 40% of the apple production area. Symptoms of apple wet core rot were observed on Elstar in January to March 2013 after 4 to 6 months’ storage in different packing houses at controlled atmosphere. The disease was present in a large number of lots harvested at orchards from different locations across the Netherlands, and incidences up to 25% were recorded. Apples exhibited light-brown wet rot, initially developing in the core and subsequently spreading into the surrounding cortex, often with a white to rose-reddish mycelium. Apples from five lots with infections (four apples per lot; 20 in total) were rinsed with sterile water, sprayed with 70% ethanol until droplet runoff and halved aseptically with a scalpel. The tissue next to the core rot was isolated and placed onto potato dextrose agar (PDA). The PDA plates were incubated at 20°C in the dark, and single-spore isolates were propagated on fresh PDA plates. All cultures formed abundant white aerial mycelium with yellow to rose pigment and a dark pink to red reverse. Macroconidia were slightly falcate, thin-walled, usually 5 septate, with a tapering apical cell, and 40 to 80×3.5 to 5 μm. Pathogen characteristics were similar to those described for F. avenaceum, causal agent of wet core rot of apple (Sanzani et al. 2013;Sørenson et al. 2009). The identity of two representative isolates (Fu1-44145 and Fu2-44145) from different apple lots was confirmed by means of multilocus gene sequencing. Genomic DNA was extracted and sequences of ITS region, TEF1-α, and histone H3 loci were amplified and sequenced. The sequences have been deposited in GenBank (Accession Nos. KT350586 and KT350587 [ITS], KT350603 and KT350604 [TEF1], KT935567 and KT935568 [HIS3]). MegaBLAST analysis revealed 99.8 to 100% identity to Fusarium spp. belonging to the F. avenaceum-F. tricinctumspecies complex. The TEF1 and HIS3 sequences of both isolates were 100% identical with F.avenaceum sequences JQ429374, GQ915502, JQ435857, and GQ915469, confirming their identity as F. avenaceum. Koch’s postulates were satisfied in two experiments, with 15 Elstar apples per isolate. In the first experiment, surface-sterilized fruits were inoculated with 20 μl of a suspension of 105conidiospores/ml prepared from a 15-day-old PDA culture after wounding with a needle. Inoculated fruits were sealed in a plastic bag and incubated in darkness at 20°C. In the second experiment, apples were surface sterilized, cut in half longitudinally, and one half was inoculated with 20 μl of the conidiospore suspension into the core of the apple. Control apple halves were inoculated with sterilized water. After inoculation, the halves were covered with plastic foil and incubated in darkness at 20°C. In both experiments, symptoms appeared after 4 to 6 days on 100% of the fruits; controls remained symptomless. Fungal colonies isolated from the lesions and cultured on PDA plates morphologically resembled the original isolates. Fusarium avenaceum is a wound pathogen that has been isolated from apple fruit in Croatia and in the United States (Kou et al. 2014; Sever et al. 2012). Only few reports describe wet core symptoms associated with F. avenaceum on apple (Sanzani et al. 2013; Sørenson et al. 2009). This is the first report of wet core rot caused by F. avenaceum on apple fruit in the Netherlands. As wet core of apple is undetectable until the fruit is cut or consumed, it affects consumer confidence. Due to potential mycotoxin production during infection, F. avenaceum infections potentially pose a safety issue (Sørenson et al. 2009).

Original languageEnglish
Pages (from-to)1501
Number of pages1
JournalPlant Disease
Volume100
Issue number7
DOIs
Publication statusPublished - 2016

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Fusarium avenaceum
Netherlands
apples
agar
fruits
potatoes
glucose
signs and symptoms (plants)
mycelium
Rosa
scalpels
infection
foil
packing houses
lesions (plant)
plastic bags
pathogens
fruit crops
plant damage

Cite this

Wenneker, M. ; Pham, K.T.K. ; Lemmers, M.E.C. ; de Boer, Fred ; van der Lans, Arie ; van Leeuwen, Paul ; Hollinger, T.C. ; Thomma, B.P.H.J. / First report of fusarium avenaceum causing wet core rot of ‘elstar’ apples in the Netherlands. In: Plant Disease. 2016 ; Vol. 100, No. 7. pp. 1501.
@article{b5364d401224489091c8bd28447da78f,
title = "First report of fusarium avenaceum causing wet core rot of ‘elstar’ apples in the Netherlands",
abstract = "Apple (Malus domestica) is an important fruit crop in the Netherlands. ‘Elstar’, the main cultivar, occupies 40{\%} of the apple production area. Symptoms of apple wet core rot were observed on Elstar in January to March 2013 after 4 to 6 months’ storage in different packing houses at controlled atmosphere. The disease was present in a large number of lots harvested at orchards from different locations across the Netherlands, and incidences up to 25{\%} were recorded. Apples exhibited light-brown wet rot, initially developing in the core and subsequently spreading into the surrounding cortex, often with a white to rose-reddish mycelium. Apples from five lots with infections (four apples per lot; 20 in total) were rinsed with sterile water, sprayed with 70{\%} ethanol until droplet runoff and halved aseptically with a scalpel. The tissue next to the core rot was isolated and placed onto potato dextrose agar (PDA). The PDA plates were incubated at 20°C in the dark, and single-spore isolates were propagated on fresh PDA plates. All cultures formed abundant white aerial mycelium with yellow to rose pigment and a dark pink to red reverse. Macroconidia were slightly falcate, thin-walled, usually 5 septate, with a tapering apical cell, and 40 to 80×3.5 to 5 μm. Pathogen characteristics were similar to those described for F. avenaceum, causal agent of wet core rot of apple (Sanzani et al. 2013;S{\o}renson et al. 2009). The identity of two representative isolates (Fu1-44145 and Fu2-44145) from different apple lots was confirmed by means of multilocus gene sequencing. Genomic DNA was extracted and sequences of ITS region, TEF1-α, and histone H3 loci were amplified and sequenced. The sequences have been deposited in GenBank (Accession Nos. KT350586 and KT350587 [ITS], KT350603 and KT350604 [TEF1], KT935567 and KT935568 [HIS3]). MegaBLAST analysis revealed 99.8 to 100{\%} identity to Fusarium spp. belonging to the F. avenaceum-F. tricinctumspecies complex. The TEF1 and HIS3 sequences of both isolates were 100{\%} identical with F.avenaceum sequences JQ429374, GQ915502, JQ435857, and GQ915469, confirming their identity as F. avenaceum. Koch’s postulates were satisfied in two experiments, with 15 Elstar apples per isolate. In the first experiment, surface-sterilized fruits were inoculated with 20 μl of a suspension of 105conidiospores/ml prepared from a 15-day-old PDA culture after wounding with a needle. Inoculated fruits were sealed in a plastic bag and incubated in darkness at 20°C. In the second experiment, apples were surface sterilized, cut in half longitudinally, and one half was inoculated with 20 μl of the conidiospore suspension into the core of the apple. Control apple halves were inoculated with sterilized water. After inoculation, the halves were covered with plastic foil and incubated in darkness at 20°C. In both experiments, symptoms appeared after 4 to 6 days on 100{\%} of the fruits; controls remained symptomless. Fungal colonies isolated from the lesions and cultured on PDA plates morphologically resembled the original isolates. Fusarium avenaceum is a wound pathogen that has been isolated from apple fruit in Croatia and in the United States (Kou et al. 2014; Sever et al. 2012). Only few reports describe wet core symptoms associated with F. avenaceum on apple (Sanzani et al. 2013; S{\o}renson et al. 2009). This is the first report of wet core rot caused by F. avenaceum on apple fruit in the Netherlands. As wet core of apple is undetectable until the fruit is cut or consumed, it affects consumer confidence. Due to potential mycotoxin production during infection, F. avenaceum infections potentially pose a safety issue (S{\o}renson et al. 2009).",
author = "M. Wenneker and K.T.K. Pham and M.E.C. Lemmers and {de Boer}, Fred and {van der Lans}, Arie and {van Leeuwen}, Paul and T.C. Hollinger and B.P.H.J. Thomma",
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First report of fusarium avenaceum causing wet core rot of ‘elstar’ apples in the Netherlands. / Wenneker, M.; Pham, K.T.K.; Lemmers, M.E.C.; de Boer, Fred; van der Lans, Arie; van Leeuwen, Paul; Hollinger, T.C.; Thomma, B.P.H.J.

In: Plant Disease, Vol. 100, No. 7, 2016, p. 1501.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - First report of fusarium avenaceum causing wet core rot of ‘elstar’ apples in the Netherlands

AU - Wenneker, M.

AU - Pham, K.T.K.

AU - Lemmers, M.E.C.

AU - de Boer, Fred

AU - van der Lans, Arie

AU - van Leeuwen, Paul

AU - Hollinger, T.C.

AU - Thomma, B.P.H.J.

PY - 2016

Y1 - 2016

N2 - Apple (Malus domestica) is an important fruit crop in the Netherlands. ‘Elstar’, the main cultivar, occupies 40% of the apple production area. Symptoms of apple wet core rot were observed on Elstar in January to March 2013 after 4 to 6 months’ storage in different packing houses at controlled atmosphere. The disease was present in a large number of lots harvested at orchards from different locations across the Netherlands, and incidences up to 25% were recorded. Apples exhibited light-brown wet rot, initially developing in the core and subsequently spreading into the surrounding cortex, often with a white to rose-reddish mycelium. Apples from five lots with infections (four apples per lot; 20 in total) were rinsed with sterile water, sprayed with 70% ethanol until droplet runoff and halved aseptically with a scalpel. The tissue next to the core rot was isolated and placed onto potato dextrose agar (PDA). The PDA plates were incubated at 20°C in the dark, and single-spore isolates were propagated on fresh PDA plates. All cultures formed abundant white aerial mycelium with yellow to rose pigment and a dark pink to red reverse. Macroconidia were slightly falcate, thin-walled, usually 5 septate, with a tapering apical cell, and 40 to 80×3.5 to 5 μm. Pathogen characteristics were similar to those described for F. avenaceum, causal agent of wet core rot of apple (Sanzani et al. 2013;Sørenson et al. 2009). The identity of two representative isolates (Fu1-44145 and Fu2-44145) from different apple lots was confirmed by means of multilocus gene sequencing. Genomic DNA was extracted and sequences of ITS region, TEF1-α, and histone H3 loci were amplified and sequenced. The sequences have been deposited in GenBank (Accession Nos. KT350586 and KT350587 [ITS], KT350603 and KT350604 [TEF1], KT935567 and KT935568 [HIS3]). MegaBLAST analysis revealed 99.8 to 100% identity to Fusarium spp. belonging to the F. avenaceum-F. tricinctumspecies complex. The TEF1 and HIS3 sequences of both isolates were 100% identical with F.avenaceum sequences JQ429374, GQ915502, JQ435857, and GQ915469, confirming their identity as F. avenaceum. Koch’s postulates were satisfied in two experiments, with 15 Elstar apples per isolate. In the first experiment, surface-sterilized fruits were inoculated with 20 μl of a suspension of 105conidiospores/ml prepared from a 15-day-old PDA culture after wounding with a needle. Inoculated fruits were sealed in a plastic bag and incubated in darkness at 20°C. In the second experiment, apples were surface sterilized, cut in half longitudinally, and one half was inoculated with 20 μl of the conidiospore suspension into the core of the apple. Control apple halves were inoculated with sterilized water. After inoculation, the halves were covered with plastic foil and incubated in darkness at 20°C. In both experiments, symptoms appeared after 4 to 6 days on 100% of the fruits; controls remained symptomless. Fungal colonies isolated from the lesions and cultured on PDA plates morphologically resembled the original isolates. Fusarium avenaceum is a wound pathogen that has been isolated from apple fruit in Croatia and in the United States (Kou et al. 2014; Sever et al. 2012). Only few reports describe wet core symptoms associated with F. avenaceum on apple (Sanzani et al. 2013; Sørenson et al. 2009). This is the first report of wet core rot caused by F. avenaceum on apple fruit in the Netherlands. As wet core of apple is undetectable until the fruit is cut or consumed, it affects consumer confidence. Due to potential mycotoxin production during infection, F. avenaceum infections potentially pose a safety issue (Sørenson et al. 2009).

AB - Apple (Malus domestica) is an important fruit crop in the Netherlands. ‘Elstar’, the main cultivar, occupies 40% of the apple production area. Symptoms of apple wet core rot were observed on Elstar in January to March 2013 after 4 to 6 months’ storage in different packing houses at controlled atmosphere. The disease was present in a large number of lots harvested at orchards from different locations across the Netherlands, and incidences up to 25% were recorded. Apples exhibited light-brown wet rot, initially developing in the core and subsequently spreading into the surrounding cortex, often with a white to rose-reddish mycelium. Apples from five lots with infections (four apples per lot; 20 in total) were rinsed with sterile water, sprayed with 70% ethanol until droplet runoff and halved aseptically with a scalpel. The tissue next to the core rot was isolated and placed onto potato dextrose agar (PDA). The PDA plates were incubated at 20°C in the dark, and single-spore isolates were propagated on fresh PDA plates. All cultures formed abundant white aerial mycelium with yellow to rose pigment and a dark pink to red reverse. Macroconidia were slightly falcate, thin-walled, usually 5 septate, with a tapering apical cell, and 40 to 80×3.5 to 5 μm. Pathogen characteristics were similar to those described for F. avenaceum, causal agent of wet core rot of apple (Sanzani et al. 2013;Sørenson et al. 2009). The identity of two representative isolates (Fu1-44145 and Fu2-44145) from different apple lots was confirmed by means of multilocus gene sequencing. Genomic DNA was extracted and sequences of ITS region, TEF1-α, and histone H3 loci were amplified and sequenced. The sequences have been deposited in GenBank (Accession Nos. KT350586 and KT350587 [ITS], KT350603 and KT350604 [TEF1], KT935567 and KT935568 [HIS3]). MegaBLAST analysis revealed 99.8 to 100% identity to Fusarium spp. belonging to the F. avenaceum-F. tricinctumspecies complex. The TEF1 and HIS3 sequences of both isolates were 100% identical with F.avenaceum sequences JQ429374, GQ915502, JQ435857, and GQ915469, confirming their identity as F. avenaceum. Koch’s postulates were satisfied in two experiments, with 15 Elstar apples per isolate. In the first experiment, surface-sterilized fruits were inoculated with 20 μl of a suspension of 105conidiospores/ml prepared from a 15-day-old PDA culture after wounding with a needle. Inoculated fruits were sealed in a plastic bag and incubated in darkness at 20°C. In the second experiment, apples were surface sterilized, cut in half longitudinally, and one half was inoculated with 20 μl of the conidiospore suspension into the core of the apple. Control apple halves were inoculated with sterilized water. After inoculation, the halves were covered with plastic foil and incubated in darkness at 20°C. In both experiments, symptoms appeared after 4 to 6 days on 100% of the fruits; controls remained symptomless. Fungal colonies isolated from the lesions and cultured on PDA plates morphologically resembled the original isolates. Fusarium avenaceum is a wound pathogen that has been isolated from apple fruit in Croatia and in the United States (Kou et al. 2014; Sever et al. 2012). Only few reports describe wet core symptoms associated with F. avenaceum on apple (Sanzani et al. 2013; Sørenson et al. 2009). This is the first report of wet core rot caused by F. avenaceum on apple fruit in the Netherlands. As wet core of apple is undetectable until the fruit is cut or consumed, it affects consumer confidence. Due to potential mycotoxin production during infection, F. avenaceum infections potentially pose a safety issue (Sørenson et al. 2009).

U2 - 10.1094/PDIS-01-16-0034-PDN

DO - 10.1094/PDIS-01-16-0034-PDN

M3 - Article

VL - 100

SP - 1501

JO - Plant Disease

JF - Plant Disease

SN - 0191-2917

IS - 7

ER -