First Report of Bacterial Soft Rot Caused by Pantoea agglomerans on Chinese Cabbage in China

Chinese yam (Dioscorea opposita Thunb.), which belongs to the family of Dioscorea, is widely naturalized throughout China, due to its high economic and medicinal value. Since 2019, water-soaked lesions were frequently observed in the underground tubers of Chinese yam located in Xinyang City, Henan Province. To identify the causal agent, ten pieces of tissue from the underground tubers with disease symptoms were collected. Those infected tissues (5×5 mm) were crushed in 500 μL sterilized water after surface sterilization and streaked onto Luria-Bertani agar plates. Pale-yellowish, rod-shaped, slimy single bacterial colonies with smooth margin were observed after 24 hours of incubation, and three bacterial colonies (named CY-1, CY-2 and CY-3) were randomly selected for further biochemical and molecular characterization. These bacteria were gram-negative with the cell length of 1.0 to 3.0 μm, width of 0.5 to 1.0 μm, and with peritrichous flagella. Subsequently, the bacteria were biochemically analyzed through BIOLOG (Hayward, CA) and identified as Pantoea agglomerans with 99% probability. Furthermore, the phylogenetic analysis results based on 16S rDNA, DNA gyrase subunit B (gyrB), and RNA polymerase sigma factor (rpoD) showed these three isolates were most closely related to P. agglomerans. The sequence of 16S rDNA, gyrB and rpoD of each strain was submitted to GenBank with the accession numbers MZ541065 MZ541066 and MZ541067 for 16S rDNA; MZ669846, MZ669847 and MZ669848 for gyrB; MZ669849, MZ669850 and MZ669851 for ropD. Pathogenicity test was performed to complete Koch’s postulates. Tubers of Chinese yam were wounded by sterile needle and inoculated with 500 μL 108 CFU/mL bacterial suspension. Sterilized water was used as a control. Five pots were inoculated for each isolate. Water-soaked lesions appeared after five days incubation at 25°C in a biochemical incubator and no lesions were observed on the control. Bacteria re-isolated from the lesions were similar in phenotypic and molecular characteristics to the original isolates. In brief, based on colony morphology, biochemical tests, characteristic sequence analysis, and pathogenicity verification, the pathogen responsible for the soft rot of Chinese yam in Henan Province was identified as P. agglomerans. In China, P. agglomerans has been reported to associate with bacterial soft rot on Chinese cabbage (Guo et al., 2020). To our knowledge, this work is the first report of bacterial rot caused by P. agglomerans on Chinese yam.

Download Full-text

First Report of Bacterial Soft Rot of Ginseng Caused by Pseudomonas qessardii in Jilin Province of China

Plant Disease ◽

10.1094/pdis-04-17-0546-pdn ◽

2018 ◽

Vol 102 (2) ◽

pp. 437-437

Author(s):

A. H. Zhang ◽

X. X. Zhang ◽

F. J. Lei ◽

L. X. Zhang

Keyword(s):

Soft Rot ◽

Jilin Province ◽

Bacterial Soft Rot ◽

First Report

Download Full-text

First Report of Bacterial Soft Rot and Blackleg on Potato Caused by Pectobacterium parmentieri in Hawaii

Plant Disease ◽

10.1094/pdis-09-19-1894-pdn ◽

2020 ◽

Vol 104 (3) ◽

pp. 970 ◽

Cited By ~ 4

Author(s):

Dario Arizala ◽

Shefali Dobhal ◽

Sujan Paudel ◽

Samudra Gunarathne ◽

Gamze Boluk ◽

...

Keyword(s):

Soft Rot ◽

Bacterial Soft Rot ◽

First Report

Download Full-text

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

Download Full-text

NITROGEN MANAGEMENT AND CULTIVAR EVALUATION FOR CONTROLLING PETIOLE SPOTTING AND BACTERIAL SOFT ROT OF CHINESE CABBAGE

Acta Horticulturae ◽

10.17660/actahortic.2004.635.19 ◽

2004 ◽

pp. 151-157 ◽

Cited By ~ 3

Author(s):

J. Warner ◽

R. Cerkauskas ◽

T. Zhang

Keyword(s):

Chinese Cabbage ◽

Soft Rot ◽

Nitrogen Management ◽

Bacterial Soft Rot

Download Full-text

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.

Download Full-text

First Report of Dickeya dianthicola Causing Blackleg and Bacterial Soft Rot on Potato in Maine

Plant Disease ◽

10.1094/pdis-12-15-1513-pdn ◽

2016 ◽

Vol 100 (11) ◽

pp. 2320-2320 ◽

Cited By ~ 14

Author(s):

H. H. Jiang ◽

J. J. Hao ◽

S. B. Johnson ◽

R. S. Brueggeman ◽

G. Secor

Keyword(s):

Soft Rot ◽

Bacterial Soft Rot ◽

First Report

Download Full-text

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.

Download Full-text