First Report of Rhizopus Head Rot of Sunflower Caused by Rhizopus arrhizus (syn. R. oryzae) in Xinjiang and Gansu Provinces of China

Bacterial stalk and head rot on sunflower (Helianthus annuus) was investigated in Konya Province of Turkey in 2008. Disease incidence was estimated as 30%. Bacteria appeared as droplets and ooze and symptoms were dark and water-soaked necrotic areas on stems and heads. Twenty-four strains were isolated from lesions on stalks and heads of sunflower cv. TR3080 from a 25-ha field and identified as Pectobacterium atrosepticum (formerly Erwinia caratovora subsp. atroseptica) (2) on the basis of biochemical, physiological (3), and molecular tests (1). Bacteria were gram negative, rod shaped, fermentative, nonfluorescent on King's B medium; positive for gelatin liquefaction, CVP test, catalase, and pectolytic activity, growth on 5% NaCl, reducing substances from sucrose, acid-production from lactose and α-methyl glucoside; and negative for growth at 37°C, acid production from sorbitol and maltose, phosphatase activity, tests for egg yolk (lecithin), sensitivity to erythromycin, and pigmentation on yeast dextrose calcium carbonate agar medium. To distinguish between P. atrosepticum and P. carotovorum, particular attention was paid to the growth at 37°C, reducing substances from sucrose and the utilization of α-methyl glucoside. Mesophyll cells of tobacco plants (Nicotiana tobaccum cv. White Burley) were infiltrated with bacterial suspensions (108 cells/ml) or water (control). Brown, collapsed areas of tissues (hypersensitive response) were observed at the injection sites after incubation for 48 h at 28°C and 80% relative humidity. A P. atrosepticum-specific primer set, Y45/Y46 (3), was used in PCR reactions to generate a 439-bp DNA fragment. Reference strains, Eca17 from Aegean University, Department of Plant Protection (İzmir, Turkey) and NCPPB 1277 from Selcuk University, Department of Plant Protection, Konya, Turkey, were employed in all biochemical, physiological, and molecular tests as positive controls and similar results were obtained. Koch's postulates were carried out to establish a causal relationship between the bacteria and the disease. A bacterial suspension (108 CFU/ml) was injected into sunflower shoot tips and inoculated plants were incubated for 2 weeks at 28°C and 80% relative humidity. All bacterial strains obtained from the stalks and heads produced the rot symptoms and ooze following inoculation to the susceptible sunflower cv. TR 3080. No symptoms were observed on controls that were inoculated with sterile water. The bacteria were isolated from the lesions on stalks and heads and their identities confirmed by the biochemical, physiological, and molecular tests. All tests were performed three times on three plants per strain. To our knowledge, this is the first report of P. atrosepticum on sunflower in Turkey. Further research is needed to determine how far the disease is spread in Turkey since other provinces also grow sunflowers. References: (1) L. Gardan et al. Int. J. Syst. Evol. Microbiol. 53:381, 2003. (2) L. Hauben et al. Syst. Appl. Microbiol. 21:384, 1998. (3) A. Darrasse et al. Appl. Environ. Microbiol. 60:298, 1994.

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First Report of Tuber Soft Rot of Jerusalem Artichoke (Helianthus tuberosus) Caused by Rhizopus arrhizus in Qinghai Province of China

Plant Disease ◽

10.1094/pdis-02-20-0280-pdn ◽

2020 ◽

Vol 104 (12) ◽

pp. 3265

Author(s):

S. P. Yang ◽

G. L. Du ◽

J. Tian ◽

X. T. Jiang ◽

X. M. Sun ◽

...

Keyword(s):

Jerusalem Artichoke ◽

Soft Rot ◽

Rhizopus Arrhizus ◽

Helianthus Tuberosus ◽

Qinghai Province ◽

First Report

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First Report of Bacterial Head Rot of Broccoli Caused by Pseudomonas fluorescens in China

Plant Disease ◽

10.1094/pdis-93-11-1219a ◽

2009 ◽

Vol 93 (11) ◽

pp. 1219-1219 ◽

Cited By ~ 2

Author(s):

B. Li ◽

G. L. Wang ◽

Z. Y. Wu ◽

W. Qiu ◽

Q. M. Tang ◽

...

Keyword(s):

Fatty Acid ◽

Pseudomonas Fluorescens ◽

Pathogenic Bacteria ◽

Disease Incidence ◽

Identification System ◽

Rrna Gene ◽

First Report ◽

Microbial Identification ◽

Microbial Identification System ◽

Head Rot

During warm and humid periods in the winters from 2005 to 2008, head rot symptoms on broccoli (cv. Sijilv) (Brassica oleracea L. var italica Planch) were observed in commercial fields in Ningbo, Zhejiang Province, China. In agreement with the report of Cui and Harling (1), water-soaked lesions developed on the buds and then progressed into a brown-black soft rot. Longitudinal sections of the symptomatic inflorescences showed brown discoloration and rotting of the internal tissues. Broccoli production is hampered by the disease, with disease incidence ranging from 65 to 81%. Bacteria were isolated by streaking on nutrient agar (3) and individual colonies formed after 2 to 3 days of incubation at 28°C. Fifteen of thirty isolates induced hypersensitive reactions (HR) on tobacco leaves (Nicotiana tabacum cv. Samsun) within 48 h. All the HR-positive strains were fluorescent on King's medium B and the colonies were smooth, convex, entire, and round. Classical bacteriological tests indicated that the fluorescent strains were gram negative, obligate aerobes, arginine dihydrolase positive, and oxidase positive. Also, the fluorescent strains were positive for the production of levan from sucrose. Five representative strains were further characterized by the Biolog Microbial Identification System, version 4.2 (Biolog Inc., Hayward, CA) and gas chromatography of fatty acid methyl esters (FAME) using the Microbial Identification System (MIDI Inc., Newark, DE) with the aerobic bacterial library (TSBA50). The five strains were identified as Pseudomonas fluorescens with Biolog and FAME similarity indexes of 0.61 to 0.68 and 0.52 to 0.58, respectively. The 16S rRNA gene sequence of broccoli strain PFB-01 (GenBank Accession No. GQ352649) was determined according to Li et al. (2). A subsequent GenBank search showed that this sequence had 98% nucleotide identity with the type strain of P. fluorescens (ATCC 17386T, GenBank Accession No. AF094726). Koch's postulates were completed by the inoculation of broccoli heads (cv. Sijilv) with cell suspensions (107 CFU/ml) of the above five strains by spraying on the surface of subcorymbs. Each treatment had five replicates. All strains induced head rot symptoms similar to those observed in natural infections. No symptoms were noted on the control plants inoculated with sterile water. Bacteria were successfully reisolated from symptomatic heads and confirmed by the cellular fatty acid composition. To our knowledge, this is the first report in China that P. fluorescens is the causal pathogen of bacterial head rot of broccoli. References: (1) X. Cui and R. Harling. Phytopathology 96:408, 2006. (2) B. Li et al. J. Phytopathol. 154:711, 2006. (3) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society. St. Paul, MN, 2001.

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First report of Rhizoctonia solani AG-1 IC causing head rot of cabbage in Japan

New Disease Reports ◽

10.5197/j.2044-0588.2017.036.012 ◽

2017 ◽

Vol 36 ◽

pp. 12 ◽

Cited By ~ 2

Author(s):

T. Misawa ◽

M. Aoki

Keyword(s):

Rhizoctonia Solani ◽

First Report ◽

Head Rot

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FIRST REPORT OF BACTERIAL HEAD ROT DISEASE CAUSED BYPECTOBACTERIUM ATROSEPTICUM ON SUNFLOWER IN PAKISTAN

Pakistan Journal of Phytopathology ◽

10.33866/phytopathol.029.01.0306 ◽

2017 ◽

Vol 29 (1) ◽

pp. 167

Author(s):

Shahzad Asad ◽

Anjum Munir ◽

Ayub Khan ◽

Ishaq Ahmad ◽

Muhammad Arshad

Keyword(s):

Agricultural Research ◽

Colony Growth ◽

Pathogenicity Test ◽

Biochemical Tests ◽

Isolation And Purification ◽

Pectobacterium Atrosepticum ◽

First Report ◽

Sunflower Crop ◽

Rot Disease ◽

Head Rot

is an important oil seed crop in Pakistan. During a field visit at National Agricultural Research Center (NARC), Islamabad, Pakistan bacterial head rot disease caused by Pectobacterium atrosepticum (formly Erwinaia caratovora subsp. atroseptica) has been observed on both local and exotic hybrids of Sunflower crop. Pathogenicity test has been carried out to fulfill Koch’s postulates. White and creamy colony growth was observed upon isolation and purification of the bacteria. Biochemical tests were conducted at Crop Diseases Research Institute (CDRI), NARC, Islamabad. Pathogenicity test has confirmed the presence of Pectobacterium atrosepticum on sunflower. This is first report documented this pathogen on sunflower crop in Pakistan.

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First Report of Cabbage Head Rot Caused by Fusarium avenaceum in Poland

Plant Disease ◽

10.1094/pdis-05-14-0507-pdn ◽

2014 ◽

Vol 98 (12) ◽

pp. 1741-1741 ◽

Cited By ~ 2

Author(s):

J. Robak ◽

A. Czubatka ◽

A. Czajka ◽

U. Smolinska

Keyword(s):

Aerial Mycelium ◽

Colony Growth ◽

The United States ◽

Control Treatment ◽

Its2 Region ◽

Academic Press ◽

Laboratory Manual ◽

First Report ◽

Head Rot ◽

Excised Tissue

Cabbage (Brassica oleracea L. var. capitata L.) is an important crop in Poland. Symptoms of a disease affecting cabbage were observed in 2012 and 2013 both in mid-August during the growing season and during storage in January and February. The disease affected about 30 to 40% of crops grown on ~9,000 ha over three locations: Charsznica in south Poland and Bedlno and Skierniewice in central Poland. Circular, watery lesions ranging from 10 to 60 mm in diameter on the surface of affected cabbage heads included whitish aerial mycelium that developed orange sporodochia in the center of each lesion. After 2 to 3 weeks, infection covered each entire cabbage head. A fungal pathogen was isolated from the orange lesions and from infected internal tissue. After sterilization of the excised tissue in 70% ethanol, the sections were each rinsed twice with sterilized water, dried on sterilized filter paper, and plated onto potato dextrose agar (PDA). Isolations consistently yielded morphologically homogeneous fungal colonies with abundant aerial mycelium that ranged from yellow to brownish yellow. The fungus produced pigmentation that changed the agar medium from dark yellow to brownish-burgundy. The mean colony growth was 66 mm after 7 days at 25°C. The fungus formed macroconidia, but microconidia and chlamydospores were not observed. Macroconidia were slender, slightly falcate, usually 3- to 5-septate, 44.7 to 60.7 × 3.7 to 5.5 μm, and formed in abundant orange sporodochia. On PDA, the isolates lost the ability to form sporodochia. Morphological and cultural features were typical of those of F. avenaceum (Fries) Saccardo (2). Koch's postulates were conducted to establish pathogenicity of each of four of the isolates on cabbage heads of the cv. Jaguar F1 (Bejo Seeds, Poland). The outer leaf of each head was inoculated with an 8-mm-diameter PDA plug colonized by the appropriate isolate (four cabbage heads/isolate), and the heads stored in a growth chamber at 25°C. After 5 to 7 days, lesions similar to those observed on naturally infested cabbage were observed on all the inoculated cabbage leaves. Four cabbage heads treated similarly with water as a control treatment remained symptomless. The experiment was repeated. DNA extracted from two of the four isolates was subjected to a PCR assay with primers ITS5 and ITS4 (4) for species identification based on the ITS1 and ITS2 sequences of ribosomal DNA (rDNA). The two sequences differed by 1 bp in the ITS2 region and had 100% identity with ITS sequences of F. avenaceum Accession Nos. AY147283 and AY147285 in GenBank. The sequences were deposited in GenBank as KM189440 and KM189441. Descriptions of fusarium head rot of cabbage in the United States (1) and Canada (3) were consistent with these observations in Poland. To our knowledge, this is the first report of F. avenaceum causing head rot of cabbage in Poland and in Europe. References: (1) H. R. Dillard and A. C. Cobb. Phytopathology 96:30. 2006. (2) J. F. Leslie and B. A. Summerell. Page 132 in: The Fusarium Laboratory Manual, Blackwell Publishing, Hoboken, NJ, 2006. (3) R. D. Peters et al. HortSci. 42:737. 2007. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

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EPIDEMIOLOGY AND CONTROL OF A SUNFLOWER HEAD ROT IN ISRAEL CAUSED BY RHIZOPUS ARRHIZUS

Canadian Journal of Plant Science ◽

10.4141/cjps70-053 ◽

1970 ◽

Vol 50 (3) ◽

pp. 283-288 ◽

Cited By ~ 5

Author(s):

M. ARNAN ◽

M. J. PINTHUS ◽

R. G. KENNETH

Keyword(s):

Helianthus Annuus ◽

Soft Rot ◽

Causal Agent ◽

Rhizopus Arrhizus ◽

Single Application ◽

Helianthus Annuus L ◽

Head Rot ◽

And Control

Injury of the heads was found to be necessary for the infection of sunflower (Helianthus annuus L.) by Rhizopus arrhizus Fischer, identified as the causal agent of a soft rot. Infection did not take place before flowering. Birds visiting the heads in search of seed were implicated in the spread of the disease. The disease was controlled by a single application of Copper 8-quinolinolate.

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