First Report of Cylindrocarpon macrodidymum Associated with Black Foot Diseases of Grapevine in Turkey

Abstract

Grape (Vitis vinifera) is widely planted and is an economically important crop in Turkey for domestic consumption and export. Black foot disease, caused by Cylindrocarpon macrodidymum Halleen, Schroers & Crous, is a recently identified but worsening problem in vineyards worldwide (3,4). Symptomatic grapevines show reduced vigor, shortened internodes, small leaves with interveinal chlorosis, and necrosis frequently leading to the death of the plants (1). Roots of symptomatic grapevines exhibit black, sunken, necrotic lesions with a reduction in root biomass. Pith of affected vines is discolored (4). During the summers of 2009 and 2010, a survey was carried out in 63 vineyards (4 to 15 years old) in six locations of Ankara Province. We collected 44 samples from roots and crowns of grapevines exhibiting black foot symptoms. In cross section, extensive necrosis at the base of the trunk and brown-black spots in xylem vessels were observed, resembling those previously reported for black foot disease (2,4). Isolations were made from roots, vascular elements, and pith tissue. In this study, 26 isolates were identified as C. macrodidymum on the basis of morphological characteristics. Isolates identified as C. macrodidymum had a dark orange-brown colony color and abundant aerial mycelia when grown on potato dextrose agar. Isolates produced ellipsoid or ovoid microconidia. The macroconidia were one to three septate, straight, and cylindrical. One-septate macroconidia were 24 to 32 × 5 to 7 μm; three-septate macroconidia were 26 to 40 × 5 to 6 μm. Chlamydospores developed in short, intercalary chains. Conidiophores were simple or complex and sporodochial. Isolate identities were confirmed by sequence analysis of the ribosomal DNA internal transcribed spacer (GenBank Accession No. HM245331) with primers ITS1 and ITS4 (4). Isolates had 99% genetic identity with other isolates of C. macrodidymum present in GenBank. In pathogenicity tests, one representative isolate was used to inoculate five grapevine plants. Tests were completed by drench inoculation onto 3-month-old rooted cuttings of cv. Sultana with 25 ml of a conidia suspension (10 ⁶ conidia ml –1 ). Controls were inoculated with an equal volume of sterile distilled water. Plants were incubated for 4 months in a controlled environment facility at 25°C. After 3 to 4 months, inoculations resulted in reduction of root mass, and C. macrodidymum was reisolated from regions of brown streaking in wood and discolored vascular tissue in all inoculated plants, fulfilling Koch's postulates. Control plants were asymptomatic and C. macrodidymum was not recovered from control plants. To our knowledge, this is the first report of the presence of C. macrodidymum causing black foot disease on grapevine in Turkey.
References: (1) S. Alaniz et al. Plant Dis. 93:821, 2009. (2) F. Hallen et al. Stud. Mycol. 50:431, 2004. (3) F. Halleen et al. Phytopathol. Mediterr. 45:S55, 2006. (4) E. Petit and W. D. Gubler. Plant Dis. 89:1051, 2005.

Full text

For Peer Review
First Report of Cylindrocarpon macrodidymum Associated
with Black Foot Diseases of Grapevine in Turkey
Journal:
Plant Disease
Manuscript ID:
PDIS-05-11-0393-PDN
Manuscript Type:
Plant Disease Note
Date Submitted by the
Author:
12-May-2011
Complete List of Authors:
ÖZBEN, Süreyya; Plant protection central research institute,
Phytopathology
Demirci, Fikret; University of Ankara, Faculty of Agriculture, Plant
Protection
DEĞĐRMENCĐ, Kemal; Plant Protection Central Research Institute,
Phytopathology
UZUNOK, Servet; Plant Protection Central Research Institute,
Phytopathology
Keywords:
Fruit < Crop Type, Pathogen detection < Subject Areas, Pathogen
diversity < Subject Areas
Plant Disease

For Peer Review
First Report of Cylindrocarpon macrodidymum Associated with Black Foot Diseases of
Grapevine in Turkey
S. Özben, Plant Protection Central Research Institute 06172 Ankara, Turkey; F. Demirci,
University of Ankara, Faculty of Agriculture, Department of Plant Protection, Ankara,
Turkey; and K. Değirmenci and S. Uzunok, Plant Protection Central Research Institute
06172 Ankara, Turkey
Grape (Vitis vinifera) is widely planted and an economically important crop in Turkey both
for domestic consumption and export. Black foot disease, caused by Cylindrocarpon
macrodidymum Halleen, Schroers & Crous, is a recently identified but worsening problem in
vineyards worldwide (1, 3). Symptomatic grapevines shows reduced vigor, shortened
internodes, small leaves with interveinal chlorosis and necrosis frequently leading to the death
of the plants (4). Roots of symptomatic grapevines exhibit black, sunken, necrotic lesions
with a reduction in root biomass. Pith of affected vines is discolored (1). During the summers
of 2009 and 2010, a survey was carried out in young vineyards of Ankara province and were
collected isolates from roots and root crown of grapevines, is 4- to 15 years-old, exhibiting
black foot symptoms. In cross section, extensive necrotic lesion the base of the trunk and
brown black spots in xylem vessels were observed resembling those previously reported for
Black foot disease (2, 1). Isolations were made from roots, vascular elements, and pith tissue.
In this study, isolates were identified as Cylindrocarpon macrodidymum on the basis of
morphological characteristics. Isolates identified as Cylindrocarpon macrodidymum were
orange-dark brown colony color and aerial mycelium abundantly formed on potato dextrose
agar. Isolates produced ellipsoid or ovoid microconidia, 1-3 septate, straight, cylindrical
macroconidia and chlamydospores in short, intercalary chains. 1-septate macroconidia were
24–32 × 5–7 µm; 3-septate macroconidia were 26-40 x 5-6 µm. Conidiophores were simple or
complex, sporodochial. Isolate identities were confirmed by sequence analysis of the ribosomal
DNA internal transcribed spacer (GenBank Accession Nos., HM245331) using primers ITS1
and ITS4 (1). Isolates had 99% genetic identity with other isolates of C. macrodidymum
present in GenBank. In pathogenicity test, one representative isolate was used to inoculate
five grapevine plants. Tests were completed by drench inoculation onto 3-month-old rooted
cuttings of ‘Sultana’ with 25 ml of conidia suspension (106 conidia ml-1). Controls were
inoculated with an equal volume of sterile distilled water. The plants were incubated for 4
months in a controlled environment facility at 25°C. After 3 to 4 months, C. macrodidymum
was reisolated from brown tissues and internal vascular lesions in all inoculated plants,
fulfilling Koch's postulates. Control plants were asymptomatic and C. macrodidymum was not
recovered. To our knowledge, this is the first report of presence C. macrodidymum causing
black foot disease on grapevine in Turkey.
References: (1) E. Petit and W. D. Gubler. Plant Dis. 89: 1051-1059, 2005. (2) F. Hallen et al.
Studıes In Mycology. 50: 431–455, 2004 (3) F. Halleen et al. Phytopathologia Mediterranea
45: S55–S67, 2006 (4) S. Alaniz et al. Plant Dis. 93: 821-825, 2009
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