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

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1819-1819 ◽  
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.

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

Plant Disease ◽  
2019 ◽  
Vol 103 (9) ◽  
pp. 2468-2468 ◽  
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

scholarly journals Emergence of Bacterial Soft Rot in Cucumber Caused by Pectobacterium carotovorum subsp. brasiliense in China

Plant Disease ◽  
2017 ◽  
Vol 101 (2) ◽  
pp. 279-287 ◽  
Author(s):  
Xianglong Meng ◽  
Ali Chai ◽  
Yanxia Shi ◽  
Xuewen Xie ◽  
Zhanhong Ma ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Soft Rot ◽  
Economic Losses ◽  
Pectobacterium Carotovorum ◽  
Bacterial Soft Rot ◽  
Bacterial Strains ◽  
Phenotypic Properties ◽  
Gene Sequence Analysis ◽  
Wide Range ◽  
Carotovorum Subsp

During 2014 to 2015, a devastating bacterial soft rot on cucumber stems and leaves occurred in Shandong, Shanxi, Hebei, Henan, and Liaoning provinces of China, resulting in serious economic losses for cucumber production. The gummosis emerged on the surface of leaves, stems, petioles, and fruit of cucumber. The basal stem color was dark brown and the stem base turned to wet rot. Yellow spots and wet rot emerged at the edge of the infected cucumber leaves and gradually infected the leaf centers. In total, 45 bacterial strains were isolated from the infected tissues. On the basis of phenotypic properties of morphology, physiology, biochemistry, and 16S ribosomal RNA gene sequence analysis, the pathogen was identified as Pectobacterium carotovorum. Multilocus sequence analysis confirmed that the isolates were P. carotovorum subsp. brasiliense, and the pathogens fell in clade II. The pathogenicity of isolated bacteria strains was confirmed. The strains reisolated were the same as the original. The host range test confirmed that strains had a wide range of hosts. As far as we know, this is the first report of cucumber stem soft rot caused by P. carotovorum subsp. brasiliense in China as well as in the world, which has a significant economic impact on cucumber production.

scholarly journals First Report of Pectobacterium carotovorum subsp. carotovorum Causing Soft Rot of Orostachys japonica in Korea

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 989-989 ◽  
Author(s):  
W. Cheon ◽  
Y. H. Jeon
Keyword(s):  
16S Rrna ◽  
Pathogenic Bacteria ◽  
Sequence Similarity ◽  
Soft Rot ◽  
Bacterial Suspension ◽  
Pectobacterium Carotovorum ◽  
First Report ◽  
Biolog System ◽  
Carotovorum Subsp ◽  
Physiological Tests

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.

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

Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1152-1152 ◽  
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.

scholarly journals First Report of Pectobacterium punjabense Causing Blackleg and Soft Rot on Potato in Hebei and Fujian Province, China

Plant Disease ◽  
2022 ◽  
Author(s):  
Utpal Handique ◽  
Yaning Cao ◽  
Dekang Wang ◽  
Ruofang Zhang ◽  
Wensi Li ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Housekeeping Genes ◽  
Soft Rot ◽  
Rrna Gene ◽  
Pectobacterium Carotovorum ◽  
Fujian Province ◽  
First Report ◽  
Potato Plants ◽  
Carotovorum Subsp

Pectobacterium spp. and Dickeya spp. cause blackleg and soft rot on potato worldwide (Charkowski, 2018). Potato plants (cv. Favorita or Jizhang 8#) with blackleg symptoms (vascular browning of crown stems, Fig. S1) were observed in the field in Zhangjiakou, Hebei province in 2018, and in Ningde, Fujian Province in 2019, in China. The disease incidence was around 50% and 10% in Zhangjiakou (5 ha) and Ningde (4 ha), respectively. Diseased plants (3 from each site) were collected to isolate the pathogen. Blackleg symptomatic stems were soaked in 75% ethanol for 2 min, rinsed and ground in sterile distilled water. Serial tenfold dilutions of the above solution were plated onto the crystal violet pectate agar (CVP) plate (Ge et al., 2018). Two to 3 days after incubation at 28°C, 4 bacterial colonies in total which digested pectin from the media and developed pit on CVP plates were purified and sequenced for identification using the universal 16S rRNA gene primer set 27F/1492R (Monciardini et al., 2002). Two colony sequences that showed more than 99% sequence identity to Pectobacterium punjabense type strain SS95 (MH249622) were submitted to the GenBank ( accession numbers: OK510280, MT242589). Additionally, six housekeeping genes proA (OK546205, OK546199), gyrA (OK546206, OK546200), icdA (OK546207, OK546201), mdh (OK546208, OK546202), gapA (OK546209, OK546203), and rpoS (OK546210, OK546204) of these two isolates were amplified and sequenced (Ma et al., 2007, Waleron et al., 2008). All strains show 99% to 100% identity with MH249622T . Phylogenetic trees based on 16S rRNA gene sequences (Fig. S2) and concatenated sequences of the housekeeping genes (Fig. S3) of the 2 isolates were constructed using MEGA 6.0 software (Tamura et al., 2013). Koch’s postulate was performed on potato seedlings and potato tubers (cv. Favorita) by injecting 100 μl bacterial suspension (105 CFU/ml) or sterile phosphate-buffered solution into the crown area of the stems or the tubers and kept at 100% humidity and 21°C for 1 day. Four days after inoculation, the infected area of the inoculated seedlings rotten and turned black, while the controls were symptomless (Fig. S4). Two days after inoculation, the infected tubers rotten and turned black, while the controls were symptomless (Fig. S4). Bacterial colonies were reisolated from these symptomatic tissues and identified using the same methods described above. Blackleg on potato plants or soft rot on potato has been reported to be caused by Pectobacterium atrosepticum, Pectobacterium carotovorum subsp. carotovorum, Pectobacterium carotovorum subsp. brasiliense, Pectobacterium parmentieri, Pectobacterium polaris in China (Zhao et al., 2018; Cao et al., 2021; Wang et al., 2021). To our knowledge, this is the first report of blackleg/soft rot of potato caused by Pectobacterium punjabense in China. We believe that this report will draw attention to the management of this pathogen in China.

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

Plant Disease ◽  
2015 ◽  
Vol 99 (8) ◽  
pp. 1175 ◽  
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

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

Plant Disease ◽  
2014 ◽  
Vol 98 (9) ◽  
pp. 1268-1268 ◽  
Author(s):  
J. Gao ◽  
N. Nan ◽  
Y. N. Liu ◽  
B. H. Lu ◽  
W. Y. Xia ◽  
...  
Keyword(s):  
Cell Suspension ◽  
16S Rdna ◽  
Soft Rot ◽  
Rdna Sequence ◽  
Jilin Province ◽  
Pectobacterium Carotovorum ◽  
Bacterial Soft Rot ◽  
16S Rdna Sequence ◽  
First Report ◽  
Carotovorum Subsp

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.

scholarly journals First Report of Soft Rot Caused by Pectobacterium carotovorum subsp. carotovorum on Cucumber in Malaysia

Plant Disease ◽  
2011 ◽  
Vol 95 (11) ◽  
pp. 1474-1474 ◽  
Author(s):  
E. Nazerian ◽  
K. Sijam ◽  
M. A. Zainal Abidin ◽  
G. Vadamalai
Keyword(s):  
Restriction Enzyme ◽  
Soft Rot ◽  
Bacterial Suspension ◽  
Pectobacterium Carotovorum ◽  
Agarose Gel ◽  
First Report ◽  
Appl Environ ◽  
Pcr Products ◽  
Carotovorum Subsp ◽  
Its Pcr

Cucumber (Cucumis sativus L.) is one of the most important vegetable fruits in Malaysia. Cucumber is principally grown in the states of Johor, Kelantan, and Perak. The broad host range Enterobacteriaceae pathogen, Pectobacterium carotovorum, can cause soft rot on stems or cucumber fruit. In Malaysia, cucumber is produced in a warm, humid climate, thus the plant is susceptible to attack by P. carotovorum at any time during production. In 2010, cucumber samples with wilted and chlorotic leaves, water-soaked lesions, and collapsed fruits were found in multiple fields. Small pieces of infected stems and fruit were immersed in 5 ml of saline solution (0.85% NaCl) for 20 min and then 50 μl of this suspension was spread onto nutrient agar (NA) and incubated at 27°C for 24 h. White-to-pale gray colonies with irregular margins were selected for analysis. For pathogenicity tests, cucumber fruits were surface sterilized by ethyl alcohol 70%, washed with sterilized distilled water, cut into small pieces, and inoculated with 20 μl of 108 CFU/ml suspensions of five representative strains. Cucumber plants were grown for 3 weeks in sterilized soil and their stems were inoculated with 20 μl of 108 CFU/ml of bacterial suspension. Inoculated samples and control (noninoculated) plants were placed in a growth chamber with 80 to 90% relative humidity at 27°C. Symptoms occurred on fruit slices and stems after 1 to 3 days and appeared the same as naturally infected samples, but the control samples remained healthy. Koch's postulates were fulfilled with the reisolation of cultures with the same characteristics as described earlier. Hypersensitivity reaction (HR) assays were done by infiltrating 108 CFU/ml of bacterial suspension into tobacco leaf epidermis and HR developed. All strains were subjected to biochemical and morphological assays, as well as molecular assessment. The strains were gram negative, facultative anaerobes, rod shaped, able to macerate potato slices and growth at 37°C; catalase positive; oxidase and phosphatase negative; able to degrade pectate; sensitive to erythromycin; negative for utilization of α-methyl glycoside, indole production, and reduction of sugars from sucrose; acid production from arabitol, sorbitol, and utilization of citrate were negative, but positive for raffinose and melibiose utilization. PCR amplification of the pel gene by Y1 and Y2 primers produced a 434-bp fragment on agarose gel 1% (1). Amplification of intergenic transcribed spacer region by G1 and L1 primers gave two main bands at approximately 535 and 580 bp on agarose gel 1.5%. The ITS-PCR products were digested with RsaI restriction enzyme (3). On the basis of biochemical and morphological characteristics, PCR-based pel gene and characterization of the ITS region, and digestion of the ITS-PCR products with RsaI restriction enzyme, all isolates were identified as P. carotovorum subsp. carotovorum. To our knowledge, this is the first report of soft rot caused by P. carotovorum subsp. carotovorum on cucumber from Malaysia. References: (1) A. Darraas et al. Appl. Environ. Microbiol. 60:1437, 1994. (2) N. W Schaad et al. Laboratory Guide for the Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society Press, St. Paul, 2001. (3) I. K. Toth et al. Appl. Environ. Microbiol. 67:4070, 2001.

scholarly journals First Report of Cabbage Soft Rot Caused by Pectobacterium carotovorum subsp. carotovorum in Malaysia

Plant Disease ◽  
2011 ◽  
Vol 95 (4) ◽  
pp. 491-491 ◽  
Author(s):  
E. Nazerian ◽  
K. Sijam ◽  
Z. A. Mior Ahmad ◽  
G. Vadamalai
Keyword(s):  
Pcr Amplification ◽  
Soft Rot ◽  
23S Rrna ◽  
Bacterial Suspension ◽  
Pectobacterium Carotovorum ◽  
Disease Symptoms ◽  
First Report ◽  
Appl Environ ◽  
Carotovorum Subsp ◽  
Its Pcr

Cabbage (Brassica oleracea L. var. capitata L.) is one of the most important vegetables cultivated in Pahang and Kelantan, Malaysia. Pectobacterium carotovorum can cause soft rot on a wide range of crops worldwide, especially in countries with warm and humid climates such as Malaysia. Cabbage with symptoms of soft rot from commercial fields were sampled and brought to the laboratory during the winter of 2010. Disease symptoms were a gray to pale brown discoloration and expanding water-soaked lesions on leaves. Several cabbage fields producing white cultivars were investigated and 27 samples were collected. Small pieces of leaf samples were immersed in 5 ml of saline solution (0.80% NaCl) for 20 min to disperse the bacterial cells. Fifty microliters of the resulting suspension was spread on nutrient agar (NA) and King's B medium and incubated at 30°C for 48 h. Purification of cultures was repeated twice on these media. Biochemical and phenotypical tests gave these results: gram negative, rod shaped, ability to grow under liquid paraffin (facultative anaerobe); oxidase negative; phosphatase negative; positive degradation of pectate; sensitive to erythromycin; negative to Keto-methyl glucoside utilization, indole production and reduction sugars from sucrose were negative; acid production from sorbitol and arabitol was negative and from melibiose, citrate, and raffinose was positive. Hypersensitivity reaction on tobacco leaf with the injection of 106 CFU/ml of bacterial suspension for all strains was positive. Four representative strains were able to cause soft rot using cabbage slices (three replications) inoculated with a bacterial suspension at 106 CFU/ml. Inoculated cabbage slices were incubated in a moist chamber at 80% relative humidity and disease symptoms occurred after 24 h. Cabbage slices inoculated with water as a control remained healthy. The bacteria reisolated from rotted cabbage slices on NA had P. carotovorum cultural characteristics and could cause soft rot in subsequent tests. PCR amplification with Y1 and Y2 primers (1), which are specific for P. carotovorum, produced a 434-bp band with 15 strains. PCR amplification of the 16S-23S rRNA intergenic transcribed spacer region (ITS) using G1 and L1 primers gave two main bands approximately 535 and 580 bp and one faint band approximately 740 bp when electrophoresed through a 1.5% agarose gel. The ITS-PCR products were digested with RsaI restriction enzyme. According to biochemical and physiological characterictics (2), PCR-based pel gene (1), and analysis by ITS-PCR and ITS-restriction fragment length polymorphism (3), all isolates were identified as P. carotovorum subsp. carotovorum. This pathogen has been reported from Thailand, Indonesia, and Singapore with whom Malaysia shares its boundaries. To our knowledge, this is the first report of P. carotovorum subsp. carotovorum in cabbage from Malaysia. References: (1) A. Darraas et al. Appl. Environ. Microbiol. 60:1437, 1994. (2) N. W. Schaad et al. Laboratory Guide for the Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, 2001. (3) I. K. Toth et al. Appl. Environ. Microbiol. 67:4070, 2001.

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