Impact of Fusarium dry rot on physicochemical attributes of potato tubers during postharvest storage

Potato tubers, under storage conditions, suffer from Fusarium dry rot disease caused by Fusarium spp. leading to devastating losses of stored tubers. Newly harvested tubers are resistance toward Fusarium infection, but disease becomes more vigorous by increasing storage period. Inoculation of potato tuber slices of Desiree cv. (highly susceptible) or Spunta cv. (highly resistant) either by a weak pathogen (F. moniliforme) or severe pathogen (F. solani) and tracking accumulation of phytoalexin rishitin in inoculated tissues at different intervals from inoculation revealed that Desiree cv. accumulated high amounts of rishitin in a very short time in comparison to another three tested situations. Dipping of potato tuber slices of both cvs. in different concentrations of the known antibiotic chloramphenicol prior to inoculation with a weak pathogen (F. moniliforme) led to increased disease severity associated with accumulation huge amounts of rishitin in inoculated tissues. The correlation coefficient between disease severity and rishitin production was +0.83. Moreover, the reaction of spunta cv. toward inoculation by a weak pathogen was changed from the state of resistance to very severe susceptibility. Since chloramphenicol affects protein synthesis on 70S ribosome’s, it was postulated that it prevents synthesis of factor(s) take a part in cell death during infection. Mitochondria extracted from potato tuber tissues secret compound(s) decreased rishitin synthesis in potato tuber slices treated with mycelia extract of F. solani. Treatment of isolated mitochondria with this antibiotic led to the elimination of this factor(s) from their secretions. Results obtained revealed that the elicitation of phytoalexins may consider one of pathogenicity factor of such system.

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First Report of Fusarium torulosum Causing Dry Rot of Seed Potato Tubers in the United States

Plant Disease ◽

10.1094/pdis-04-11-0291 ◽

2011 ◽

Vol 95 (9) ◽

pp. 1194-1194 ◽

Cited By ~ 6

Author(s):

E. Gachango ◽

W. Kirk ◽

L. Hanson ◽

A. Rojas ◽

P. Tumbalam

Keyword(s):

United States ◽

Sodium Hypochlorite ◽

Fusarium Species ◽

The United States ◽

Distilled Water ◽

Potato Tubers ◽

Dry Rot ◽

Fusarium Dry Rot ◽

Half Strength ◽

Potato Dry Rot

Fusarium dry rot of potato (Solanum tuberosum L.) is a postharvest disease caused by several Fusarium species and is of worldwide importance. Thirteen species of Fusarium have been implicated in fungal dry rots of potatoes worldwide. Among them, eight species have been reported in the northern United States (2). In Michigan potato production, F. sambucinum was the predominant species reported to be affecting seed potato in storage and causing seed piece decay after planting (3). Some previous identifications of F. sambucinum as dry rot may have been F. torulosum since F. torulosum was previously classified within F. sambucinum (4). To further investigate this, dry rot symptomatic tubers were collected from Michigan seed lots in the summers of 2009 and 2010. Small sections from the margins of necrotic regions were cut with a scalpel, surface sterilized in 0.5% sodium hypochlorite for 10 s, rinsed twice in sterile distilled water, and blotted with sterile filter paper. The tissue pieces were plated on half-strength potato dextrose agar (PDA) amended with 0.5 g/liter of streptomycin sulfate and incubated at 23°C for 5 to 7 days. Cultures resembling Fusarium species were transferred onto water agar, and single hyphal tips from actively growing isolates were removed and plated either on carnation leaf agar (CLA) or on half-strength PDA to generate pure cultures. Among the Fusarium isolates obtained, five isolates were identified as F. torulosum (GenBank Accessions Nos. JF803658–JF803660). Identification was based on colony and conidial morphology on PDA and CLA, respectively. These features included slow growth (2.8 ± 0.2 cm in 5 days), white mycelium that became pigmented with age, narrow concentric rings, red or white pigmentation on agar, macroconidia (32.4 ± 0.4 μm average length) with five septa, a pointed apical cell, and a foot-shaped basal cell (4). The identity was confirmed through DNA extraction followed by amplification and sequencing of the translation elongation factor (EF-1α) gene region (1). The Fusarium-ID.v (1) and the NCBI database were used to obtain the closest match (99%) to previously sequenced materials (GenBank Accession No. AJ543611). Pathogenicity testing was done on disease-free potato tubers cv. Red Norland. Tubers were surface sterilized for 10 min in 0.5% sodium hypochlorite and rinsed twice in distilled water. Three tubers per isolate were injected with 20 μl of a conidial suspension (106 conidia/ml) made from F. torulosum cultures grown on PDA for 7 to 10 days. Control tubers were injected with 20 μl of sterile distilled water. All tubers inoculated with F. torulosum developed typical potato dry rot symptoms consisting of a brown and dry decay. There was no disease incidence on the control tubers. F. torulosum was reisolated from the symptomatic tubers. To our knowledge, this is the first report of F. torulosum causing potato dry rot in the United States. References: (1) D. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (2) L. E. Hanson et al. Phytopathology 86:378, 1996. (3) M. L. Lacy and R. Hammerschmidt. Fusarium dry rot. Extension Bulletin. Retrieved from http://web1.msue.msu.edu/msue/iac/onlinepubs/pubs/E/E2448POT , 23 May 2010. (4) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Wiley-Blackwell, Hoboken, NJ, 2006.

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First Report of Potato Tuber Sprout Rot Caused by Fusarium sambucinum in Michigan

Plant Disease ◽

10.1094/pd-90-1460b ◽

2006 ◽

Vol 90 (11) ◽

pp. 1460-1460 ◽

Cited By ~ 13

Author(s):

P. S. Wharton ◽

P. Tumbalam ◽

W. W. Kirk

Keyword(s):

Fusarium Sambucinum ◽

Potato Tubers ◽

Tuber Tissue ◽

Dry Rot ◽

First Report ◽

Seed Tubers ◽

Fusarium Dry Rot ◽

Whole Seed ◽

Cut Seed ◽

Cut Surface

Fusarium dry rot is one of the most important diseases of potato (Solanum tuberosum L.), affecting tubers in storage and whole seed or seed pieces after planting (2). Fusarium sambucinum Fuckel (teleomorph Giberella pulicaris) is the most common pathogen causing dry rot of stored tubers in North America. (4). Cut seed potato tubers of cvs. FL1879 and Pike with severe sprout rot were collected in Michigan during May 2006. As well as having rotted sprouts, all diseased tubers had dry rot. When diseased sprouts were cut in half, brown, necrotic lesions could be seen spreading down the center of the sprout in vascular tissue and at the base of the sprout in tuber tissue. Pathogen isolations were made from both infected tuber tissue and diseased sprouts on potato dextrose agar (PDA). In both cases, only F. sambucinum was isolated from diseased sprout and tuber tissue. Identification of the pathogen was based on colony and conidial morphology. This included white, fluffy mycelium on the surface and crimson coloration of the colonies viewed from the underside of PDA plates and large distinctive macroconidia (3). Identification was confirmed by comparison of ITS (internal transcribed spacer) sequence data with reference isolates. The ITS region of rDNA was amplified by polymerase chain reaction (PCR) with primers ITS1/ITS4 and sequenced. BLASTn analysis (1) of the sequence obtained showed a 100% homology with F. sambucinum Fuckel. For inoculum production, isolates were grown on PDA at 8°C for 14 days prior to inoculation. Pathogenicity was tested in potato tubers of cv. FL1879 with a single isolate collected from diseased sprouts. Whole seed tubers with 4 mm long sprouts were cut in half longitudinally with a sterile knife to ensure that seed pieces had viable sprouts. The cut surfaces of seed pieces were spray inoculated with 200 ml of conidial suspension (1 × 104 conidia ml-1) over the entire cut surface to give a final dosage of approximately 1 ml per seed piece. Care was taken to limit inoculum spray to the cut surface so that sprouts were not inoculated. Seed pieces (40 per replicate × 4 replicates) were then placed in plastic boxes (30 × 15 × 10 cm) and incubated in the dark at 18°C and 95% relative humidity for 30 days in a controlled environment chamber. As a control, cut seed pieces were spayed with sterile distilled water and incubated as above. All tubers inoculated with the pathogen developed typical Fusarium dry rot symptoms consisting of a brown, dry decay of tuber tissue with mycelial lined cavities. Sprouts on inoculated tubers developed symptoms that were observed in the initially collected seed pieces, and F. sambucinum was reisolated from all infected sprouts. The noninoculated control tubers did not develop any symptoms of dry rot. The results of the pathogenicity tests indicate that F. sambucinum caused sprout rot on potato seed pieces. Since only the cut surfaces of tubers were inoculated, it is assumed that infection of sprouts is systemic through the tuber. To our knowledge, this is the first report of F. sambucinum causing a sprout rot of developing sprouts on seed tubers in the United States. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) L. E. Hanson et al. Phytopathology 86:378, 1996. (3) P. E. Nelson et al. Pages 118–119 in: Fusarium Species: An Illustrated Manual for Identification. The Pennsylvania State University, University Park and London, 1983. (4) G. A. Secor and B. Salas. Fusarium dry rot and Fusarium wilt. Pages 23–25 in: Compendium of Potato Diseases. 2nd ed. W. R. Stevenson et al., eds. The American Phytopathological Society, St. Paul, MN, 2001.

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Identification of Fusarium spp. Associated with Potato Tubers in Upper Egypt by Morphological and Molecular Characters

Asian Journal of Biochemistry, Genetics and Molecular Biology ◽

10.9734/ajbgmb/2019/v2i330062 ◽

2019 ◽

pp. 1-14 ◽

Cited By ~ 1

Author(s):

Youssuf A. Gherbawy ◽

Mohamed A. Hussein ◽

Eman G. A. El-Dawy ◽

Nabila A. Hassany ◽

Saad A. Alamri

Keyword(s):

Solanum Tuberosum L ◽

Fusarium Species ◽

Correct Diagnosis ◽

Potato Tubers ◽

Fusarium Spp ◽

Dry Rot ◽

Upper Egypt ◽

Fusarium Dry Rot ◽

Global Population ◽

Highly Virulent

Potato (Solanum tuberosum L.) is an important crop which holds promise for food security considering the global population growth rate. Fusarium dry rot is one of the most significant diseases of potato. To build up strategies for the control of this disease, it ought to be made primarily a correct diagnosis and identification of the pathogen. A total of 504 Fusarium isolates were recovered from potato tubers collected from Upper Egypt. Fusarium isolates were identified based on morphology and partial DNA sequencing of β-tubulin (TUB) genes. 62.5% of the isolates were identified as F. sambucinum, followed F. oxysporum (57.5%), then F. verticillioides (56.25%) and F. incarnatum (47.5%). All the tested Fusarium species were able to produce amylase. The pathogenicity of the isolates was tested by inoculation of healthy potato tubers; all of the tested isolates were pathogenic to healthy potato tubers. F. sambucinum had a highly virulent effect.

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First Report of Fusarium graminearum Causing Dry Rot of Potato in North Dakota

Plant Disease ◽

10.1094/pd-89-0105b ◽

2005 ◽

Vol 89 (1) ◽

pp. 105-105 ◽

Cited By ~ 21

Author(s):

S. Ali ◽

V. V. Rivera ◽

G. A. Secor

Keyword(s):

North Dakota ◽

Distilled Water ◽

Conidial Suspension ◽

State University ◽

Potato Tubers ◽

Pennsylvania State University ◽

Dry Rot ◽

Fusarium Dry Rot ◽

Half Strength ◽

Potato Dry Rot

Fusarium dry rot of potato can be caused by several species of Fusarium, but F. sambucinum is considered the primary cause in stored potatoes in North America and Europe (2). Potato tubers of cvs. Shepody and Russet Burbank with severe dry rot were collected from a commercial processing storage facility in central North Dakota during 2003–2004. Pathogen isolations were made from infected tubers on one-half strength acidified potato dextrose agar (APDA). Only F. graminearum was isolated from all rotted tubers used. Identification was based on colony morphology and conidial and perithecial characteristics, which included a carmine coloration of the underside of the agar and white fluffy mycelium on APDA, the presence of black perithecia on carnation leaf agar, and large distinctive macroconidia (1). The identity was confirmed by the Fusarium Research Institute at Pennsylvania State University. Pathogenicity was tested in potato tubers and greenhouse-grown potato plants cv. Atlantic. Nine tubers were wounded by removal of a plug of tissue with a cork borer, 3 mm in diameter and 5 mm deep, and inoculated by placing either 100 μl of a conidial suspension (5 × 104 conidia per ml) from a 7-day-old culture or a mycelial plug, 3 mm in diameter, from a 7-day-old culture in the wound. Nine tubers wounded and treated with either sterile distilled water or one-half strength APDA served as controls. Plant inoculations were performed by cutting a slit in the lower stem with a sterile scalpel and placing a cotton collar saturated with a conidial suspension (5 × 104 conidia per ml) around the wound and held in place with a clothespin. Four plants were inoculated with a conidial suspension, and four plants were treated with sterile distilled water. All tubers inoculated with either Fusarium treatment developed typical potato dry rot symptoms consisting of a brown, dry decay with mycelium lined cavities, and F. graminearum was reisolated from all symptomatic tubers. The control tubers did not develop symptoms. No symptoms developed in any of the greenhouse inoculated plants. Fifteen isolates were tested for sensitivity to thiabendazole, and all were sensitive with EC50 (50% effective concentration) values ranging from 0.8 to 3.7 μl/ml. The results indicate that F. graminearum can cause dry rot of potato, and to our knowledge, this is the first report of F. graminearum as a cause of potato dry rot. These results have epidemiological implications in the persistence, spread, and management of F. graminearum in cereals and potatoes, since potato is often used in rotation with other hosts of F. graminearum, including wheat, barley, and corn. References: (1) P. E. Nelson et al. Pages 118–119 in: Fusarium Species: An Illustrated Manual for Identification. The Pennsylvania State University, University Park and London, 1983. (2) G. A. Secor and B. Salas. Fusarium dry rot and fusarium wilt. Pages 23–25 in: Compendium of Potato Diseases. 2nd ed. W. R. Stevenson, R. Loria, G. D. Franc, and D. P. Weingartner, eds. The American Phytopathological Society, St. Paul, MN, 2001.

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