First Report of Bacterial Soft Rot of Horn Lian (Typhonium giganteum) Caused by Pectobacterium carotovorum subsp. carotovorum in Jilin Province of China

Horn lian (Typhonium giganteum) is a perennial herb of the family Aracea and is commonly used for expelling phlegm and as an antispasmodic treatment. In August 2012, horn lian grown in Changchun, Jilin Province of China, exhibited soft rot disease with ~60% incidence and experienced great losses. Water-soaked and dark green lesions on leaves expanded along main veins. Semitransparent, water-soaked, and sunken lesions on stems expanded rapidly and caused the whole plant to collapse with a foul smell. Nine representative strains were isolated from infected leaves and stems on nutrient agar (NA) medium after 36 h incubation at 28°C (1). Colonies were round, shiny, grayish white, and convex on NA medium. All strains were gram-negative, non-fluorescent on King's B medium (KB), facultatively anaerobic, motile with three to six peritrichous flagella (observed by electron transmission microscope), positive for catalase and pectolytic activity test on potato slices, but negative for oxidase, urease, and lecithinase. Strains grew at 37°C and in yeast salts broth medium containing 5% NaCl. They also liquefied gelatin and reduced nitrate, but did not reduce sucrose. Strains were also negative for starch hydrolysis, malonate utilization, gas production from glucose and indole. Results were variable for the Voges-Proskauer test. The strains utilized sucrose, arabinose, fructose, D-galactose, D-glucose, inositol, lactose, D-mannose, D-mannitol, melibiose, rhamnose, salicin, trehalose, maltose, raffinose, glycerol, D-xylose, and cellobiose as carbon sources, but not melezitose, α-CH3-D-gluconate, sorbitol, or dulcitol. Species identity was confirmed by molecular characterization of one of the nine strains, DJL1-2. DNA GC content indicated by high performance liquid chromatography (HPLC) was 51.7%. The 16S rDNA sequence (KC07897) of DJL1-2 showed 99% identity to that of a Pectobacterium carotovorum subsp. carotovorum (Pcc) strain (CP001657) and the sequence of the 16S-23S rDNA spacer region (KJ623257) was 93% similar to that of another known strain of Pcc (CP003776). As a result, the strains were identified as Pcc (2). Pathogenicity of the nine strains was evaluated by spraying 1 ml of bacterial cell suspension (108 CFU/ml) onto healthy leaves and injecting 0.1 ml of cell suspension into stems of 3-year-old horn lian plants with a sterile pipette tip. Three seedlings were used for each strain and sterilized water served as negative controls. Pcc SMG-2 reference strain (from milk thistle) was also inoculated into horn lian leaves and stems. Inoculated plants were covered with plastic bags for 24 h in a greenhouse at 28 to 30°C. After 72 h, water-soaked lesions similar to the naturally infected plants were observed on leaves and stems inoculated by the nine isolated strains and Pcc SMG-2, while negative control plants remained symptomless. Biochemical tests and 16S rDNA sequence analysis confirmed that the re-isolated bacteria were Pcc. To our knowledge, this is the first report of Pcc causing bacterial soft rot of horn lian in Changchun, Jilin Province, China. References: (1) Z. D. Fang. Research Method of Phytopathology. China Agricultural Press, 1998. (2) N. W. Schaad, et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria, 3rd ed. American Phytopathological Society, St. Paul, MN, 2001.

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First Report of Bacterial Soft Rot of Milk Thistle (Silybum marianum) Caused by Pectobacterium carotovorum subsp. carotovorum in Jilin Province of China

Plant Disease ◽

10.1094/pdis-02-14-0137-pdn ◽

2014 ◽

Vol 98 (8) ◽

pp. 1152-1152 ◽

Cited By ~ 1

Author(s):

J. Gao ◽

N. Nan ◽

B. H. Lu ◽

Y. N. Liu ◽

X. Y. Wu ◽

...

Keyword(s):

16S Rdna ◽

Soft Rot ◽

Jilin Province ◽

Milk Thistle ◽

Pectobacterium Carotovorum ◽

Bacterial Soft Rot ◽

Silybum Marianum ◽

16S Rdna Sequence ◽

First Report ◽

Carotovorum Subsp

Milk thistle (Silybum marianum) is an annual or biannual plant of the Asteraceae family that produces the hepaprotectant silymarin. In 2012, almost all milk thistle grown in the medicinal herbal garden of Jilin Agricultural University (Changchun, Jilin Province, China) exhibited symptoms of a previously undetected soft rot disease. Initial symptoms on stems appeared as tan, semitransparent, and water-soaked, then became sunken. The rotted lesions expanded rapidly and inner stem tissues were rotten with a foul smell. Eventually, the whole plant became black, then collapsed and died. Economic losses were significant as the seed crop was almost completely lost. Nine bacterial strains were isolated from tissues on nutrient agar (NA) medium after 36 h incubation at 28°C (1). Colonies of the nine strains were round, shiny, grayish white, and convex on NA medium. All strains were gram-negative, non-fluorescent, facultatively anaerobic, motile with two to four peritrichous flagella (observed by electron transmission microscope), positive for catalase and potato rot, but negative for oxidase and lecithinase. Strains grew at 37°C and in yeast salts broth medium containing 5% NaCl. They also liquefied gelatin. Strains were also negative for starch hydrolysis, malonate utilization, gas production from glucose, and indole. Results were variable for the Voges-Proskauer test and production of H2S from cysteine. The strains utilized esculin, fructose, D-galactose, D-glucose, inositol, lactose, D-mannose, D-mannitol, melibiose, rhamnose, salicin, trehalose, D-xylose, and cellobiose as carbon sources, but not melezitose, α-CH3-D-gluconate, sorbitol, or starch. Glycerol and maltose were only weakly utilized. Species identity was confirmed by molecular analysis of one of the strains, SMG-2. HPLC indicated a DNA GC content of 50.55%. The 16S rDNA sequence (KC207898) of SMG-2 showed 99% sequence identity to that of a Pectobacterium carotovorum subsp. carotovorum strain (DQ333384) and the sequence of the 16S-23S rDNA spacer region (KJ415377) was 95% similar to that of another known strain of P. carotovorum subsp. carotovorum (AF232684). Based on biochemical and physiological characteristics (2), as well as 16S rDNA gene analysis, the strains were identified as P. carotovorum subsp. carotovorum. Pathogenicity of the nine strains was evaluated by depositing a bacterial suspension (108 CFU/ml) on wounded stems (made with a disinfected razor blade) of 3-month-old milk thistle plants. Three plants were inoculated with each strain and three plants were treated with sterilized water as negative controls. Inoculated plants were covered with plastic bags for 24 h in a greenhouse at 28 to 30°C. After 48 h, the plants inoculated with bacteria showed similar symptoms as the naturally infected plants, while control plants remained symptomless. The symptoms observed on inoculated stems were rotten and sunken tissues. Bacteria were re-isolated from the inoculated plants and confirmed to be identical to the original strains based on 16S rDNA sequence analysis. To our knowledge, this is the first report of P. carotovorum subsp. carotovorum causing bacterial soft rot of milk thistle in Changchun, Jilin Province, China. References: (1) Z. D. Fang. Research Method of Phytopathology. China Agricultural Press (In Chinese), 1998. (2) N. W. Schaad et al., eds. Laboratory Guide for Identification of Plant Pathogenic Bacteria, 3rd ed. American Phytopathological Society, St. Paul, MN, 2001.

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First Report of Bacterial Soft Rot of Potato Caused by Pectobacterium carotovorum subsp. brasiliense in Guangdong Province, China

Plant Disease ◽

10.1094/pdis-03-19-0653-pdn ◽

2019 ◽

Vol 103 (9) ◽

pp. 2468-2468 ◽

Cited By ~ 1

Author(s):

S. B. Jiang ◽

B. R. Lin ◽

Q. Y. Yang ◽

J. X. Zhang ◽

H. F. Shen ◽

...

Keyword(s):

Guangdong Province ◽

Soft Rot ◽

Pectobacterium Carotovorum ◽

Bacterial Soft Rot ◽

First Report ◽

Carotovorum Subsp

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First Report of Bacterial Soft Rot of Potato Caused by Pectobacterium carotovorum subsp. carotovorum in Guangdong Province of China

Plant Disease ◽

10.1094/pdis-07-12-0620-pdn ◽

2012 ◽

Vol 96 (12) ◽

pp. 1819-1819 ◽

Cited By ~ 1

Author(s):

J. X. Zhang ◽

B. R. Lin ◽

H. F. Shen ◽

X. M. Pu ◽

Z. N. Chen ◽

...

Keyword(s):

Guangdong Province ◽

Housekeeping Genes ◽

Soft Rot ◽

Bacterial Suspension ◽

Pectobacterium Carotovorum ◽

Bacterial Soft Rot ◽

First Report ◽

Wide Range ◽

Carotovorum Subsp ◽

Agar Media

Potato (Solanum tuberosum L.) is a major crop in China, with 80.0 million tons being produced in 2010 on 3.3 million ha. Pectobacterium carotovorum subsp. carotovorum Jones 1901; Hauben et al. 1999 causes soft rot worldwide on a wide range of hosts including potato, carrot, and cabbage. During spring 2010, a soft rot with a foul smell was noted in stored potato tubers of different cultivars in the Guangdong Province. Symptoms on tubers appeared as tan, water-soaked areas with watery ooze. The rotted tissues were white to cream colored. Stems of infected plants with typical inky black symptoms could also be found in the fields prior to harvest. Three different potato fields were surveyed, and 13% of the plants had the symptoms. Twenty-seven samples (three symptomatic tubers per sample) were collected. Bacteria were successfully isolated from all diseased tissues on nutrient agar media supplemented with 5% sucrose and incubated at 26 ± 1°C for 36 h. After purification on tripticase soy agar media, four typical strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) were identified using the following deterministic tests: gram-negative rods, oxidase negative, facultatively anaerobic, able to degrade pectate, sensitive to erythromycin, negative for phosphatase, unable to produce acid from α-methyl-glucoside, and produced acid from trehalose. Biolog analysis (Ver 4.20.05, Hayward, CA) identified the strains as P. carotovorum subsp. carotovorum (SIM 0.808, 0.774, 0.782, and 0.786, respectively). The identity of strains 7-3-1 (GenBank Accession No. JX258132), 7-3-2 (JX258133), and 8-3-1 (JX196705) was confirmed by 16S rRNA gene sequencing (4), since they had 99% sequence identity with other P. carotovorum subsp. carotovorum strains (GenBank Accession Nos. JF926744 and JF926758) using BLASTn. Further genetic analysis of strain 8-3-1 was performed targeting informative housekeeping genes, i.e., acnA (GenBank Accession No. JX196704), gabA (JX196706), icdA (JX196707), mdh (JX196708), mtlD (JX196709), pgi (JX196710), and proA (JX196711) (2). These sequences from strain 8-3-1 were 99 to 100%, homologous to sequences of multiple strains of P. carotovorum subsp. carotovorum. Therefore, strain 8-3-1 grouped with P. carotovorum subsp. carotovorum on the phylogenetic trees (neighbor-joining method, 1,000 bootstrap values) of seven concatenated housekeeping genes when compared with 60 other strains, including Pectobacterium spp. and Dickeya spp. (3). Pathogenicity of four strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) was evaluated by depositing a bacterial suspension (106 CFU/ml) on the potato slices of cultivar ‘Favorita’ and incubating at 30 ± 1°C. Slices inoculated with just water served as non-inoculated checks. The strains caused soft rot within 72 h and the checks had no rot. Bacteria were reisolated from the slices and were shown to be identical to the original strains based on morphological, cultural, and biochemical tests. Although this pathogen has already been reported in northern China (1), to our knowledge, this is the first report of P. carotovorum subsp. carotovorum causing bacterial soft rot of potato in Guangdong Province of China. References: (1) Y. X. Fei et al. J. Hexi Univ. 26:51, 2010.(2) B. Ma et al. Phytobacteriology 97:1150, 2007. (3) S. Nabhan et al. Plant Pathol. 61:498, 2012. (4) W. G. Weisbury et al. J. Bacteriol. 173:697, 1991.

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First Report of Bacterial Soft Rot of Seleng Wormwood Caused by Pectobacterium carotovorum subsp. carotovorum in China

Plant Disease ◽

10.1094/pdis-12-14-1324-pdn ◽

2015 ◽

Vol 99 (8) ◽

pp. 1175 ◽

Cited By ~ 2

Author(s):

Y. Tian ◽

Y. Zhao ◽

H. Xie ◽

X. Wang ◽

J. Fan ◽

...

Keyword(s):

Soft Rot ◽

Pectobacterium Carotovorum ◽

Bacterial Soft Rot ◽

First Report ◽

Carotovorum Subsp

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First Report of Pectobacterium carotovorum subsp. carotovorum and P. carotovorum subsp. odoriferum Causing Bacterial Soft Rot of Sweetpotato in China

Plant Disease ◽

10.1094/pdis-11-15-1370-pdn ◽

2016 ◽

Vol 100 (8) ◽

pp. 1776-1776 ◽

Cited By ~ 4

Author(s):

B. Gao ◽

R. Y. Wang ◽

S. L. Chen ◽

J. Ma ◽

X. H. Li

Keyword(s):

Soft Rot ◽

Pectobacterium Carotovorum ◽

Bacterial Soft Rot ◽

First Report ◽

Carotovorum Subsp

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First Report of Pantoea sp. Induced Soft Rot Disease of Pleurotus eryngii in Korea

Plant Disease ◽

10.1094/pd-91-0109a ◽

2007 ◽

Vol 91 (1) ◽

pp. 109-109 ◽

Cited By ~ 9

Author(s):

M. K. Kim ◽

J. S. Ryu ◽

Y. H. Lee ◽

H. D. Yun

Keyword(s):

16S Rdna ◽

Water Drop ◽

Soft Rot ◽

Pleurotus Eryngii ◽

Rdna Sequence ◽

Pantoea Ananatis ◽

16S Rdna Sequence ◽

First Report ◽

Soft Rot Disease ◽

Rot Disease

The king oyster mushroom, Pleurotus eryngii, has become a popular crop because of its unique flavor and texture and is cultivated in many areas in Korea. In 2003, symptoms of water-soaked lesions and soft rot in the stipes and pileus of cultivated P. eryngii was observed in Jinju, Korea. Diseased tissue was plated on nutrient media. Dominate colonies were yellow, convex, circular with smooth margins, and had a shiny texture. Computer analysis of the data gathered, using the API kit (50CHE, bioMérieux, Marcy-l'Etoile, France), showed that the strain belongs to the Enterobacteriaceae. Although the API system did not give an exact identification, the metabolic profile of the bacterial strain closely resembled the database profile of Pantoea sp. (positive for acid production from the fermentation of d-fructose, d-galactose, d-glucose, d-trehalose, and d-ribose and negative for oxidase, urease, pectate, and thiosulfate). The 16S rDNA sequence of the bacterium was determined (GenBank Accession No. AY530796). When compared with those in GenBank, the bacterium was determined to belong to the Enterobacteriaceae family of the Gammaproteobacteria, and the highest degree of sequence similarity was found to be with Pantoea ananatis strain BD 588 (97.4%) and Pantoea ananatis strain Pna 97-1 (97.3%). In the phylogenetic tree, the bacterium clearly related to the Pantoea lineage, as evidenced by the high bootstrap value. A BLAST search with 16S rDNA sequence of the bacterium supported the API results that the isolate belongs to a species of Pantoea. Pathogenicity tests of this new Pantoea isolate were carried out with bacterial suspensions (approximately 1 × 106 CFU/ml) that were grown for 24 h in Luria-Bertani broth cultures. These were used to inoculate directly on the mycelia of P. eryngii that had been cultivated for 35 days in a plastic bottle. The water and broth were also inoculated to another set of bottles as a control experiment. Inoculated bottles were incubated in a cultivation room at 16 to 17°C with relative humidity between 80 and 95%. Early symptoms of the disease included a dark brown water drop that developed on hypha and primordium of the mushrooms after 5 to 7 days. After 13 days, water-soaked lesions developed on the stipes and pileus, and the normal growth of the mushrooms was inhibited. An offensive odor then developed along with a severe soft rot that was similar to the disease symptoms observed under natural conditions. Mushrooms in control bottles did not develop symptoms. Koch's postulates were fulfilled by isolating bacteria from typical lesions from inoculated mushrooms that were identical to the inoculated strain in colony morphology and biochemical characteristics. Pantoea ananatis was first reported as a pathogen of pineapple fruit causing brown rot (3). Several bacterial diseases, such as brown blotch on cultivated mushrooms by Pseudomonas tolaasii (2) and bacterial soft rot on winter mushroom by Erwinia carotovora subsp. Carotovora, causing severe damage to mushrooms are known (1). However, no Pantoea sp. induced disease of edible mushroom has been previously reported. To our knowledge, this is the first report of soft rot disease on P. eryngii caused by Pantoea sp. References: (1) H. Okamoto et al. Ann. Phytopathol. Soc. Jpn. 65:460. 1999. (2) S. G. Paine. Ann. Appl. Biol. 5:206. 1919. (3) F. B. Serrano. Philipp. J. Sci. 36:271, 1928.

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First Report of Artichoke Bacterial Stem Rot Caused by Pectobacterium carotovorum subsp. carotovorum in China

Plant Disease ◽

10.1094/pdis-04-11-0314 ◽

2011 ◽

Vol 95 (8) ◽

pp. 1026-1026 ◽

Cited By ~ 2

Author(s):

B.-D. Gao ◽

X.-L. Wang ◽

H. Xia

Keyword(s):

16S Rdna ◽

Chinese Cabbage ◽

Vascular Tissue ◽

Soft Rot ◽

Hunan Province ◽

Pectobacterium Carotovorum ◽

Globe Artichoke ◽

Bacterial Cells ◽

First Report ◽

Carotovorum Subsp

A new disease on globe artichoke (Cynara scolymus L.) was observed in the springs of 2008 and 2009 and during the spring and fall seasons of 2010 in commercial fields (nearly 1,000 ha) in Changde, Hunan Province, China. Characteristic symptoms were wilting and necrosis of the outermost leaves and dark brown discoloration of the vascular tissue and pith of the stem base. Eventually, the plants wilted and died. Nearly 5, 35, and 4% (2008, 2009, and 2010, respectively) of the artichoke fields were destroyed because of the disease. Manual weeding and cuttings often led to the development of typical soft rot during propagation. To investigate the causal agent of the disease, isolations were made from rotted stems of field artichoke plants on nutrient agar (NA). Bacteria consistently isolated from the diseased tissues formed gray-white, glossy, convex, translucent, and round colonies on NA. The bacterial cells were gram-negative rods with two to eight peritrichous flagella. Ten isolates were negative for oxidase, arginine dehydrolase, H2S, gelatin liquefaction, and tryptophan ammonialyase. Isolates were positive for catalase, reduced NO3 to NO2, indole, glucuroide, galactosidase, Voges-Proskauer test, and β-galactosidase, along with being facultatively anaerobic and insensitive to erythromycin (40 μg/ml). Negative results were obtained for utilization of maltose, gluconate, and phenylacetic acid, and positive results were obtained from arabinose, glucose, mannose, N-acetyl-glucosamine, mannitol, and sodium citrate for all isolates. Acid was produced from glucose, inositol, rhamnose, melibiose, arabinose, mannitol, sucrose, and amarogentin. All test results were similar to reference strain PCC1000 (GenBank Accession No. JF721959) of Pectobacterium carotovorum subsp. carotovorum. These isolates could also cause soft rot of Chinese cabbage stem, carrot slice, pepper, lettuce and artichoke stems, and tomato and potato slices within 48 h at 28°C in an artificial inoculation test (3). PCR amplification was carried out by utilizing universal 16S rDNA primer pair 16SF/16SR and pel gene primers Y1/Y2 (1). The 16S rDNA and pel gene sequences of isolate HNXDT002 (GenBank Accession Nos. JF721958 and JF721960, respectively) had 99 and 93% nucleotide identity with strains of P. carotovorum subsp. carotovorum (GenBank Accession Nos. U80197 and CP001657, respectively). Pathogenicity was confirmed by needle-stab inoculation (1 × 108 CFU/ml) at the stem on three healthy artichoke plants held at 28°C for 48 h. Sterile distilled water was used as a negative control. Within 72 h after inoculation, water-soaking and soft-rot symptoms were observed on all inoculated artichoke plants, while controls remained healthy. The bacterium was recovered only from rotted stems of inoculated plants. In recent years, P. carotovorum was reported on such plants as Pinellia ternata (4) and Chinese cabbage (2) in China. To our knowledge, this is the first report of bacterial rot disease caused by P. carotovorum subsp. carotovorum on artichoke in China. References: (1) D. J. Brenner et al. Bergey's Manual of Systematic Bacteriology. Vol. 2. Springer, NY, 2005. (2)Y. Fang et al. Acta Microbiol. Sinica 44:136, 2004. (3) H. Yi-Bo et al. Acta Phytopathol. Sinica 37:338, 2007. (4) F. X. Ying et al. Plant Dis. 91:1359, 2007.

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