scholarly journals First Report of Bacterial Stem Rot Caused by Pectobacterium carotovorum subsp. carotovorum and P. carotovorum subsp. atrosepticum on Grafted Eggplant in Italy

Plant Disease ◽  
2001 ◽  
Vol 85 (8) ◽  
pp. 921-921 ◽  
Author(s):  
V. Catara ◽  
P. Bella ◽  
G. Polizzi ◽  
A. Paratore

In December 1999, widespread dieback of eggplant (Solanum melongena L., hybrid Mission Bell), grafted onto the interspecific hybrid Beaufort (Lycopersicon esculentum × Lycopersicon hirsutum) and on tomato hybrid Energy, was observed during four rootstock evaluation trials in greenhouses in Sicily, Italy. Dark brown to black, firm but sometimes fissured lesions, 1 to 20 cm long, were observed just above the grafting point. Water-soaked, soft, dark green lesions that turned brown with age were observed on the upper stem. Extensive discoloration of vascular tissues and, in some cases, breakdown of the pith and stem hollowness occurred. Eggplant seedlings, present in the same experimental trials, did not show any symptoms. From symptomatic tissues, numerous bacterial colonies were obtained on nutrient dextrose agar. Bacteria from purified colonies were gram-negative, oxidase-negative, facultatively anaerobic pectolitic on crystal violet pectate agar, which is nonfluorescent on King's B medium. On the basis of biochemical and physiological tests (1), seven of 10 isolates were identified as Pectobacterium carotovorum subsp. carotovorum (Jones 1901) Hauben et al. 1999, comb. nov. (2), and the remaining three were identified as P. carotovorum subsp. atrosepticum (van Hall 1902) Hauben et al. 1999, comb. nov. (2). Four days after prick inoculation of the stems of eggplant and tomato plants, all isolates caused extensive collapse of stems and internal brown discoloration and hollowness, respectively. In a second pathogenicity test, basil leaves of grafted eggplants and eggplant seedlings were either removed or left intact. These plants were then sprayed with bacterial suspensions (108 CFU/ml) of one isolate of each pathogen. Plants were held at 100% relative humidity or in a low-moisture incubator. After 6 days incubation, stem lesions and vascular discoloration, typical of symptoms observed in greenhouses, were observed on plants held at 100% relative humidity. No symptoms were observed in unwounded plants or plants maintained in low relative humidity. Similar symptoms on grafted eggplant have been attributed to physiological disorders (3). To our knowledge, only P. carotovorum subsp. carotovorum has been reported on eggplant as causing fruit rot. References: (1) N. W. Schaad, ed. 1988. Laboratory Guide for Identification of Plant Pathogenic Bacteria, 2nd ed. American Phytopathological Society, St. Paul, MN. (2) L. Hauben et al. Int. J. Syst. Bacteriol. 41:582, 1999. (3) G. Ginoux and H. Laterrot. Rev. Horticole (Paris) 321:49, 1991.

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 989-989 ◽  
Author(s):  
W. Cheon ◽  
Y. H. Jeon

Orostachys japonica (Maxim) A. Berger is an important traditional medicine in Korea. The extract of this plant has antioxidant activity and suppresses cancer cell proliferation (1). From summer through fall of 2012 and 2013, a high incidence (~10% to 30%) of disease outbreaks of all plants characterized by water-soaked lesions and soft rot with a stinky odor was observed in cultivated O. japonica around Uljin (36°59′35.04″N, 126°24′1.51″E), Korea. Water-soaked lesions were first observed on the stem base of plants. Subsequently, the plants collapsed, although the upper portion remained asymptomatic. Thereafter, the lesions expanded rapidly over the entire plant. To isolate potential pathogens from infected leaves, small sections (5 to 10 mm2) were excised from the margins of lesions. Ten bacteria were isolated from ten symptomatic plants. Three representative isolates from different symptomatic plants were used for identification and pathogenicity tests. Isolated bacteria were gram negative, pectolytic on crystal violet pectate agar, nonfluorescent on King's medium B, and elicited a hypersensitive response in tobacco plants. All isolates caused soft rot of potato tubers. These isolates also differed from isolates of Erwinia chrysanthemi (Ech) that they were insensitive to erythromycin and did not produce phosphatase. These isolates differed from known strains of E. carotovora subsp. atroseptica in that they did not produce reducing substances from sucrose (2). Use of the Biolog GN microplate and the Release 4.0 system identified the isolate as Pectobacterium carotovorum subsp. carotovorum with 81.2% similarity. The 16S rRNA of the isolated bacteria was amplified by PCR and sequenced as described by Weisburg et al. (3). A BLAST analysis for sequence similarity of the 16S rRNA region revealed 99% similarity with nucleotide sequences for P. carotovorum subsp. carotovorum isolates (KC790305, KC790280, JF926758, JX196705, and AB680074). The pathogenicity of three bacterial isolates was examined on three 2-year-old O. japonica plants by adding 50 μl of a bacterial suspension containing 108 CFU/ml when wounding the leaves with sterile needles. Ten control plants were inoculated with sterilized water. After inoculation, plants were maintained in a growth chamber at 25°C with relative humidity ranging from 80 to 90%. After 2 to 3 days, tissue discoloration, water-soaked lesions, and soft rot developed around the inoculation point. Severe symptoms of soft rot and darkening developed on leaves of inoculated plants within 3 to 5 days after inoculation. All controls remained healthy during these experiments. The bacterial strains re-isolated from the parts of the leaf showing the symptoms and identified as P. carotovorum subsp. carotovorum on the basis of the biochemical and physiological tests, as well as Biolog system. The results obtained for pathogenicity, Biolog analysis, and molecular data corresponded with those for P. carotovorum subsp. carotovorum. To our knowledge, this is the first report of the presence of P. carotovorum on O. japonica in Korea. References: (1) C.-H. Kim et al. Kor. J. Med. Crop Sci. 11:31, 2003. (2) N. W. Schaad et al. Erwinia Soft Rot Group. Page 56 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et al. eds. American Phytopathological Society, St. Paul. MN, 2001. (3) W. G. Weisburg et al. J. Bacteriol. 173:697, 1991.


2021 ◽  
Author(s):  

Abstract P. vexans is a pynicidial anamorph with a teleomorph in the genus Diaporthe. Easily seedborne and producing large numbers of conidia, it causes disease in Solanum melongena [aubergine/brinjal/eggplant], its only significant host. This ranges from poor seed germination and damping-off of seedlings, to leaf and stem lesions and to fruit rot, both in the field and after harvest. The fungus has been reported from widely distributed areas of most continents, but only a few of those are in Europe and Africa, even though the climates are favourable. Seed transmission may explain its broad historical distribution, but limitation of its host range to a non-staple vegetable crop can allow for its avoidance and eradication by cultural methods. As a result, perhaps, it does not appear often on lists of restricted pathogens, even though it may cause yield losses of more than 50%.


Plant Disease ◽  
2008 ◽  
Vol 92 (8) ◽  
pp. 1247-1247 ◽  
Author(s):  
M. H. Nam ◽  
T. I. Kim ◽  
M. L. Gleason ◽  
J. Y. Song ◽  
H. G. Kim

Symptoms typical of anthracnose fruit rot; sunken, dark brown lesions on maturing fruits, were found in a commercial field of strawberry (Fragaria × ananassa) cv. Cal Giant in Yangyang County, Korea in May 2007. Masses of conidia were produced in acervuli in the center of lesions. The fungus was isolated on potato dextrose agar (PDA). Colonies grown on PDA were pale to mouse gray and became dark green to black in reverse. Conidia were formed in orange-to-salmon pink masses in the center of the culture. The average size of conidia on PDA was 15.2 × 4.6 μm, and they were hyaline, straight, cylindrical, with pointed ends, and aseptate (1). The fungus did not form an ascigerous stage in culture. Mycelial growth rate was 7.5 mm per day at 25°C on PDA. The identity of two isolates was confirmed as Colletotrichum acutatum J.H. Simmonds by PCR amplification using species-specific primers TBCA and TB5 (2), resulting in a characteristic 330-bp band on agarose gel. Morphological characters were in accordance with previous reports on C. acutatum. A pathogenicity test was conducted with five healthy plants of cvs. Cal Giant, Maehyang, Seolhyang, Kumhyang, Akihime, and Redpearl. After fruits and flowers were sprayed with a conidia suspension (105 conidia per ml), the plants were maintained at 10 to 25°C and 100% relative humidity in a greenhouse. As a control, five healthy plants were sprayed with sterile distilled water and incubated under the same conditions. Dark brown, water-soaked spots appeared on mature fruits of all cultivars after 5 days, and lesions on green fruits appeared on individual achenes. Flowers developed dark lesions, dried out, and died. No symptoms were found on the control plants. After the pathogen was reisolated from fruits and flowers lesions, the morphological characters developed in culture as described above. To our knowledge, this is the first report of C. acutatum causing strawberry anthracnose in Korea. References: (1) B. J. Smith and L. L. Black. Plant Dis. 74:69, 1990. (2) P. Talhinhas et al. Appl. Environ. Microbiol. 71:2987, 2005.


Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1504-1504 ◽  
Author(s):  
K. Gašic ◽  
V. Gavrilović ◽  
Ž. Ivanović ◽  
A. Obradović

In September 2012, soft rot symptoms on broccoli (Brassica oleracea L. var. italica Plenck) were observed in several commercial fields in the western part of Serbia. Following the first harvest, water-soaked areas developed on broccoli stem tissue and progressed into soft rot decay of entire plants. The incidence of disease was approximately 30%. In Serbia, broccoli is grown on smaller fields compared to other vegetables, but its production and consumption increased significantly in recent years. From the diseased tissue, shiny, grayish white, round colonies were isolated on nutrient agar. Six non-fluorescent, gram-negative, facultative anaerobic, oxidase-negative, and catalase-positive bacterial strains were chosen for further identification. All strains caused soft rot on potato and carrot slices and did not induce hypersensitive reaction on tobacco leaves. They grew at 37°C and in yeast salts broth medium containing 5% NaCl (2), did not produce acid from α-methyl glucoside, but utilized lactose and trehalose, and did not produce indole or lecitinase. Investigated strains formed light red, 1.5-mm-diameter colonies on Logan's medium (2), and did not produce blue pigmented indigoidine on glucose yeast calcium carbonate agar (2) nor “fried egg” colonies on potato dextrose agar. Based on biochemical and physiological characteristics (1) and ITS-PCR and ITS-RFLP analysis (4), the strains were identified as Pectobacterium carotovorum subsp. carotovorum. The 16S rRNA gene sequence from two strains (GenBank KC527051 and KC527052) showed 100% identity with sequences of P. carotovorum subsp. carotovorum previously deposited in GenBank (3). Pathogenicity of the strains was confirmed by inoculation of broccoli head tissue fragments. Three florets per strain were inoculated by pricking the petals with a syringe and hypodermic needle and depositing a droplet of bacterial suspension (approx. 1 × 108 CFU/ml) at the point of inoculation. Sterile distilled water was used as a negative control. Inoculated florets were placed in a sealed plastic container and incubated in high humidity conditions at 28°C. Tissue discoloration and soft rot developed around the inoculation point within 48 to 72 h. No symptoms developed on control florets. Identity of bacterial strains reisolated from inoculated plant tissues was confirmed by ITS-PCR using G1/L1 primers followed by digestion of PCR products with Rsa I restriction enzyme (4). In Serbia, P. carotovorum subsp. carotovorum has been isolated from potato, some vegetable crops, and ornamentals, but not from broccoli until now. References: (1) S. H. De Boer and A. Kelman. Page 56 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria, 3rd ed. N. W. Schaad et al., eds. The American Phytopathological Society, St. Paul, MN, 2001. (2) P. C. Fahy and A. C. Hayward. Page 337 in: Plant Bacterial Diseases: A Diagnostic Guide. P. C. Fahy and G. J. Persley eds. Academic Press, New York, 1983. (3) S. Nabhan et al. J. Appl. Microbiol. 113: 904, 2012. (4) I. K. Toth et. al. Appl. Environ. Microbiol. 67:4070, 2001.


Author(s):  
E. Punithalingam

Abstract A description is provided for Phomopsis vexans[Diaporthe vexans]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Solanum melongena, S. wendlandii. DISEASE: The only economic host is eggplant or brinjal (Solanum melongena) and the disease is variously known as tip over, stem blight or canker, leaf blight or spot and fruit rot; damping-off can also take place. Leaf spots (up to 3 cm diam.) are conspicuous, irregular in outline and may coalesce; lower leaves may be affected first. In stem lesions the cortex dries and cracks, plants become stunted and girdling cankers cause death. Fruit spots are pale, sunken, conspicuous and may affect the whole fruit; fruit may drop or remain attached, becoming mummified after a soft decay. Pycnidia are abundant. GEOGRAPHICAL DISTRIBUTION: Widespread in N. America, the West Indies, and E. and central Asia, also in Africa (Senegal, Tanzania, Zambia) and Mauritius (CMI Map 329, ed. 2, 1968). The record from Australia (NSW) should be deleted. Additional records not yet mapped are: Brunei, Haiti, Iran, Iraq, Rumania. TRANSMISSION: Host debris and seed from infested fruit are primary sources of inoculum. Naturally infected seed germinates less well and more slowly (20: 621; 22: 511).


Plant Disease ◽  
2020 ◽  
Author(s):  
Sanja Marković ◽  
Slaviša Stanković ◽  
Aleksandra Jelušić ◽  
Renata Ilicic ◽  
Andrea Kosovac ◽  
...  

Blackleg outbreaks were noticed on three fields (total c. 100 ha) during two consecutive years (2018, 2019) in one of the main potato growing areas in Serbia (Bačka region, Vojvodina). The percentage of infected plants reached 40-70% with 10.5% to 44.7% yield reductions. From the three fields out of 90 samples Pectobacterium carotovorum subsp. brasiliensis was most frequently identified and diagnosed as causal agent of potato blackleg in Serbia for the first time (29 isolates). Dickeya dianthicola was a less frequently causative bacterium, which was also noticed for the first time (nine isolates). A total of 38 isolates were characterized based on their phenotypic and genetic features, including a pathogenicity test on potato. The repetitive element Polymerase Chain Reaction (rep-PCR) using BOX, REP and ERIC primer pairs differentiated five genetic profiles among 38 tested isolates. Multilocus sequence analysis (MLSA) of four housekeeping genes, acnA, gapA, icdA and mdh, revealed the presence of three so far unknown P. c. subsp. brasiliensis multilocus genotypes and confirmed clustering into two main genetic clades as determined in other studies. MLSA also revealed the presence of a new genotype of D. dianthicola in Serbia.


Plant Disease ◽  
2008 ◽  
Vol 92 (2) ◽  
pp. 317-317 ◽  
Author(s):  
S. Aranda ◽  
M. Montes-Borrego ◽  
F. J. Muñoz-Ledesma ◽  
R. M. Jiménez-Díaz ◽  
B. B. Landa

Opium poppy (Papaver somniferum L.) is an economically important pharmaceutical crop in Spain. Approximately 8,000 ha are cultivated annually in southern and central Spain. To improve yields, opium poppy cultivation is expanding to more humid or irrigated areas of Spain. In the springs of 2005 and 2007, we observed poppy plants with wilt and stem rot symptoms in irrigated, commercial opium poppy (cv. Nigrum) at Carmona and Écija, which are in Seville Province in southern Spain. Closer observations of affected plants revealed darkening and water soaking of the leaves and stem at the soil level, wilting of the lower leaves or the entire plant, and dark brown discoloration of stem vascular tissues and pith of the plant. Severely affected plants became completely rotten and collapsed. Isolations from symptomatic tissues on nutrient agar consistently yielded bacterial colonies. Pure cultures of four representative bacterial strains (two per each of affected field and year of isolation) were used in triplicate for a comparative analysis of biochemical and physiological traits in the ‘carotovora’ group of Erwinia (1) with known isolates of Pectobacterium carotovorum subsp. carotovorum, P. carotovorum subsp. atrosepticum, and Dickeya chrysanthemi. The isolates from opium poppy were gram negative, facultatively anaerobic, oxidase negative, catalase positive, grew at 37°C, and did not produce gas from D-glucose. Acid was produced from D(+)-arabinose, lactose, and D(+)-trehalose, but not from α-D-methylglucoside. In addition, the opium poppy bacterial isolates caused soft rot on potato slices within 24 h at 25°C and did not induce a hypersensitive reaction on tobacco leaves. Use of the Biolog GN microplates and the OmniLog ID 1.2 system identified the four poppy isolates as P. carotovorum (showing a 66.7% similarity with the subsp. carotovorum). Pathogenicity of poppy isolates was tested on three 6-week-old opium poppy plants (cv. Nigrum) by injecting 100 μl of a bacterial suspension containing 108 CFU/ml in the basal stem. Plants that served as controls were injected with sterile water. Plants were incubated in a growth chamber adjusted to 28°C, 90% relative humidity, and a 14-h photoperiod of fluorescent light of 360 μE·m-2·s-1. Severe symptoms of soft rot and darkening developed on stems of inoculated plants within 3 to 5 days after inoculation. No symptoms developed on control plants. Bacterial strains reisolated from inoculated plants were identified as P. carotovorum on the basis of the Biolog system, as well as biochemical and physiological characters. To our knowledge, this is the first report of P. carotovorum causing soft rot of commercial opium poppy crops in Spain and elsewhere. The presence of this bacterial pathogen to irrigated crops and humid areas may pose an important constraint on the yield of opium poppy crops in Spain. References: (1) R. S. Dickey and A. Kelman. Pages 44-59 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. N. W. Schaad, ed. The American Phytopathological Society, St. Paul, MN, 1988.


Plant Disease ◽  
2019 ◽  
Vol 103 (10) ◽  
pp. 2667-2667 ◽  
Author(s):  
N. Zlatković ◽  
A. Prokić ◽  
K. Gašić ◽  
N. Kuzmanović ◽  
M. Ivanović ◽  
...  

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