DNA based detection of blackleg and soft rot disease causing Erwinia strains in seed potatoes

Author(s):  
Yeshitila Degefu ◽  
Sanna Jokela ◽  
Erkki Joki-Tokola ◽  
Elina Virtanen

Erwinia carotovora subsp. atroseptica (Eca), Erwinia carotovora subsp. carotovora (Ecc) and Erwinia chrysanthemi (Ech) are the different sub species of Erwinia that cause the diseases commonly known as blackleg, aerial stem rot and soft rot on potato. Blackleg and aerial stem rot affect vines during the growing season, whereas soft rot affects tubers in the field and during transit and storage. The three species can cause soft rot under cool and moist conditions. E. carotovora subsp. atroseptica is the major cause of blackleg, a blackening of the stem base of potato plants, which originates from the mother tuber (Pérombelon and Kelman, 1987). Erwinia carotovora subsp. carotovora mainly causes aerial stem rot (aerial blackleg), but under high temperatures it has been reported to cause blackleg like symptoms. E. chrysanthemi also induces blackleg-like symptoms. Until recently E. chrysanthemi had been mainly confined to warmer climates of Europe, Australia and the tropics. To date the species has been known to occur in cool temperate regions including Finland. In Finland E. chrysanthemi the strain has been reported for the first time in 2004 and it appears to spread fast in certain parts of country (Degefu, unpublished, Pirhonen, personal communication). Although infested crop residues and rotting tubers are among the important sources of inoculum, latent infections in seed tuber provide the major source of infection in potato production (Hannukkala and Segertedt, 2004). At the seed potato laboratory MTT, Ruukki we are carrying out research and services on PCR (DNA) based detection of latent infection of blackleg and soft rot Erwinia strains. The enrichment of the bacteria in semi selective liquid medium prior to PCR ( BIO-PCR) is an important initial step for the success in PCR detection extremely low number of the target bacteria from tubers. The different strains appear to differ in their ability to compete with other saprophytes and reach the target detection limit of bacterial population during the enrichment culture of the potato peel extract. Results of prior PCR enrichment of the bacteria, detection limits of the different strains and preliminary data, from the analysis of some seed lots from the high grade area of north Ostrobothnia and Åland regions, on the occurrence of the strains and the new trends of introduction and spread of E. chrysanthemi in Finland are presented and discussed. Evaluation of the current status of Erwinia diagnostics and areas of future research are highlighted

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Yeshitila Degefu

Recent methodological developments have uncovered the etiological diversity of the potato blackleg and soft rot Pectobacteriaceae. At least five species in the genera Dickeya and Pectobacterium have been confirmed to cause blackleg on potatoes in Finland. The bacteria are seed borne and remain latent in the tuber until conditions favourable for growth, multiplication and infection prevail. Tubers could be infected by one or more of these species. This short communication is based on the results of molecular detection data collected for more than 14 years from potato seed lots produced in Finland. Diagnostic PCR assay specific to Dickeya solani, Pectobacterium atrosepticum, Pectobacterium carotovorum, P. brasiliense and P. parmentieri revealed that potatoes are infected by one or more of these species; it also revealed that single species infection is more common than multiple colonization. An event of simultaneous occurrences of different strains from the Pectobacterium species appears to be more frequent than that observed between Dickeya and Pectobacterium species. The absence of co-occurrence of Dickeya solani and Pectobacterium atrosepticum is intriguing.


Plant Disease ◽  
2021 ◽  
Author(s):  
Wanxin Han ◽  
Jinhui Wang ◽  
Zheng Li ◽  
Yang Pan ◽  
Dai Zhang ◽  
...  

Pectobacterium species cause blackleg, soft rot and stem rot in potato and many other vegetable crops (Charkowski 2015). In July 2020, potato plants showing characteristic symptoms of aerial stem rot were observed in a field (cv. Xisen 6) in Fengning Manchu Autonomous County, Chengde, Hebei Province (North China). The disease incidence in that field (5 ha in size) was more than 50%. Putative pectolytic bacteria were obtained from symptomatic stem tissues (light brown and water-soaked stem sections) by culturing on the crystal violet pectate (CVP) medium. Bacterial colonies producing pits, were restreaked and purified on Luria-Bertani (LB) agar. The isolates causing stem rot were gram negative and rod shaped, negative for oxidase, urease, indole production, gelatin liquefaction and acid production from maltose and D-sorbitol. All isolates were catalase positive, produced acid from lactose, rhamnose, saccharose, raffinose and D-arabinose, and were tolerant to 5% NaCl, and able to utilize citrate. The bacterial gDNA was extracted using the EasyPure Bacteria Genomic DNA Kit (TransGen Biotech). The 16S rDNA region was amplified by PCR using the universal primer pair 27F/1492R and sequenced. Result of the Blastn analysis of the 16S rDNA amplicons (MZ379788, MZ379789) suggested that the isolates FN20111 and FN20121 belonged to the genus Pectobacterium. To determine the species of the stem rot Pectobacterium isolates, multi-locus sequence analysis (MLSA) was performed with six housekeeping genes acnA, gapA, icdA, mdh, proA and rpoS (MZ403781-MZ403792), and phylogenetic tree was reconstructed using RAxML v8.2.12 (https://github.com/stamatak/standard-RAxML). The result of phylogenetic analysis showed that the stem rot Pectobacterium isolates FN20111 and FN20121 clustered with P. versatile (syn. ‘Candidatus Pectobacterium maceratum’) strains CFBP6051T (Portier et al. 2019), SCC1 (Niemi et al. 2017) and F131 (Shirshikov et al. 2018). And the isolates FN20111 and FN20121 were more closely related to the type strain CFBP6051T than to strains SCC1 and F131. Potato seedlings (cv. Xisen 6 and Favorita) were inoculated with the isolates FN20111 and FN20121 by injecting 100 µl of bacterial suspensions (108 CFU·mL-1) into the upper parts of the stems of potato plants, or injected with 100 µl of 0.9% saline solution as control. The seedlings were grown at 28°C and 50% relative humidity. Three days post-inoculation, only the bacteria-inoculated seedlings showed diseased symptoms resembling to those observed in the field. Bacterial colonies were obtained from the infected stems and were identified using the same PCR primers of housekeeping genes as described above, fulfill Koch’s postulates. P. versatile causing soft rot and blackleg on potato plants has been reported in Finland (Niemi et al. 2017), Russia (Shirshikov et al. 2018), Netherlands (Portier et al. 2019), Poland (Waleron et al. 2019) and in New York State (Ma et al. 2021). To our knowledge, this is the first report of P. versatile causing aerial stem rot of potato in China.


Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 129-129 ◽  
Author(s):  
C. A. Clark ◽  
M. W. Hoy ◽  
J. P. Bond ◽  
C. Chen ◽  
Y.-K. Goh ◽  
...  

Bacterial root and stem rot of sweetpotato (Ipomoea batatas (L.) Lam.) was first fully characterized in the U.S. in 1977 (2). It was thought to be caused exclusively by Erwinia chrysanthemi. Although a previous report described sweetpotato as a host for E. carotovora subsp. carotovora, based on artificial inoculations, others have reported that neither E. carotovora subsp. carotovora nor E. carotovora subsp. atroseptica decay sweetpotato storage roots (1). In October 1995, storage roots of sweetpotato cv. Beauregard were received from St. Landry Parish, LA, that displayed typical bacterial root rot. Isolations from these roots yielded bacteria that showed a similarity of 0.945 to E. carotovora subsp. carotovora with the Biolog GN Bacterial Identification System (version 3.50). This isolate (Ecc-LH) also differed from isolates of E. chrysanthemi (Ech) from sweetpotato and other hosts in that it was insensitive to erythromycin, did not produce phosphatase or lecithinase, and did not produce gas from glucose. Ecc-LH differed from known strains of E. carotovora subsp. atroseptica in that it did not produce reducing substances from sucrose or acid from palatinose. When Beauregard storage roots were inoculated by inserting micropipette tips containing 50 μl of 1.0 × 108 CFU/ml, both Ecc-LH and Ech-48 produced typical bacterial root rot symptoms. However, when they were compared by infectivity titrations at 28 to 32°C, Ecc-LH was less virulent than Ech-48. Ecc-LH had an ED50 of approximately 1.0 × 106 CFU/ml and did not cause appreciable disease below inoculum concentrations of 1.0 × 105, whereas Ech-48 had an ED50 of approximately 1.0 × 108 and caused soft rot at the lowest concentration tested, 1.0 × 103. Similar disease incidence was observed in infectivity titrations at 22 to 24°C, but Ech-48 caused less severe soft rot. E. carotovora subsp. carotovora was reisolated from inoculated storage roots and its identity was reconfirmed by Biolog. When terminal vine cuttings of Beauregard were dipped in 1.0 × 108 CFU/ml and planted in a greenhouse, bacterial stem rot symptoms developed on plants inoculated with Ech-48 at about 4 weeks postinoculation, or when new growth began. However, no symptoms developed on plants inoculated with Ecc-LH. This is the first report of natural occurrence of E. carotovora subsp. carotovora causing bacterial root rot of sweetpotato in Louisiana. E. chrysanthemi remains the most important pathogen causing bacterial soft rot in sweetpotato since it is widely associated with sweetpotato, is more virulent on storage roots and also causes a stem rot. E. carotovora subsp. carotovora can cause root rot, but has been isolated in only one location to date, is less virulent on storage roots, and apparently does not cause stem rot on the predominant cultivar in U.S. sweetpotato production, Beauregard. References: (1) C. A. Clark and J. W. Moyer. 1988. Compendium of Sweet Potato Diseases. American Phytopathological Society, St. Paul, MN. (2) N. W. Schaad and D. Brenner. Phytopathology 67:302, 1977.


1980 ◽  
Vol 58 (2) ◽  
pp. 270-280
Author(s):  
Gabrielle-Françoise Vogt

Root cells of young pumpkins (Cucurbita pepo L.), infected by a 30-min exposure to a phytopathogenic bacterium, Erwinia carotovora (Jones) Holland, show an activation of the cell wall polysaccharides' renovation. The processes of exocytosis and endocytosis which take place lead to a plasmic renovation. Hypotheses concerning certain moments of this turnover and its possible phytopathologic consequences may constitute the basis of future research.


Plant Disease ◽  
2004 ◽  
Vol 88 (3) ◽  
pp. 310-310 ◽  
Author(s):  
R. Cetinkaya-Yildiz ◽  
M. Mirik ◽  
Y. Aysan ◽  
M. Kusek ◽  
F. Sahin

Severe outbreaks of bacterial stem rot disease occurred on dieffenbachia plants (Dieffenbachia amoena cv. Tropic Snow) during the autumn and spring seasons of 2002 and 2003 in two commercial glasshouses (3.5 ha) near Adana and Mersin in the Eastern Mediterranean Region of Turkey. Characteristic symptoms of the disease were wilting of the lower leaves, darkening and water soaking of the leaves and stem at or below the soil level, and browning in the vessel and pith of the diseased plants. Eventually, the stem and leaves completely rotted, and the plants collapsed. Nearly 30 and 40% (2002 and 2003, respectively) of the 20,000 potted plants in the glasshouses were destroyed because of the disease. Cuttings often developed a typical soft rot during propagation. Disease incidence was estimated at approximately 50% on propagating material during 2003. Isolations were made from rotted stems, leaves, and discolored vessels of the dieffenbachia plants on King's medium B. Bacteria consistently isolated from the diseased tissues formed white-to-cream colonies on the medium. Bacteria from purified colonies were gram, oxidase, and arginine dyhidrolase negative, catalase positive, and facultative anaerobic. Ten representative strains all fermented glucose and reduced nitrates to nitrites. The strains caused soft rot of potato slices within 24 h at 25°C. All strains were resistant to erythromycin in an antibiotic disk (15 μg) assay. Negative results were obtained from utilization of α-methyl glycoside, reducing substance from sucrose, and indole production from tryptophane and phosphathase activity. Positive results were obtained from pectate, aesculin, and gelatine liquefaction for all strains. Acid was produced from glucose, sucrose, mannitol, mannose, lactose, raffinose, melibiose, trehalose, and L(+)-arabinose but not Darabinose, sorbitol, inulin, and maltose. Pathogenicity was confirmed by needle-stab inoculation at the stem on three plants each of dieffenbachia and tomato plants (5-week-old cv. H-2274). Sterile distilled water was used as a negative control. All plants were covered with polyethylene bags for 48 h at 25°C. Within 72 h after inoculation, water-soaking and soft-rot symptoms were observed on dieffenbachia and tomato plants. All of the bacterial strains isolated in the present study were identified as Erwinia carotovora subsp. carotovora (Jones) based on fatty acid methyl ester analysis with similarity indices ranging from 80 to 94%. Furthermore, Biolog GN (Department of Plant Protection, Faculty of Agriculture, Ataturk University, Erzurum, Turkey) profiles identified them as the same pathovar with similarity values of 67 to 72%. All of the test results were similar to those of reference strain GSPB 435 (Gottinger Sammlung phytopathogener Bakterien, Georg-August University, Gottingen, Germany) of E. carotovora subsp. carotovora used in this study. To our knowledge, this is the first report of the occurrence and outbreak of a bacterial rot disease on dieffenbachia grown in the Eastern Mediterranean Region of Turkey. Contaminated cuttings may be the primary source of inoculum within and between glasshouses.


2020 ◽  
Vol 18 ◽  
Author(s):  
Rina Das ◽  
Dinesh Kumar Mehta ◽  
Meenakshi Dhanawat

Abstract:: A novel virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), appeared and expanded globally by the end of year in 2019 from Wuhan, China, causing severe acute respiratory syndrome. During its initial stage, the disease was called the novel coronavirus (2019-nCoV). It was named COVID-19 by the World Health Organization (WHO) on 11 February 2020. The WHO declared worldwide the SARS-CoV-2 virus a pandemic on March 2020. On 30 January 2020 the first case of Corona Virus Disease 2019 (COVID-19) was reported in India. Now in current situation the virus is floating in almost every part of the province and rest of the globe. -: On the basis of novel published evidences, we efficiently summarized the reported work with reference to COVID-19 epidemiology, pathogen, clinical symptoms, treatment and prevention. Using several worldwide electronic scientific databases such as Pubmed, Medline, Embase, Science direct, Scopus, etc were utilized for extensive investigation of relevant literature. -: This review is written in the hope of encouraging the people successfully with the key learning points from the underway efforts to perceive and manage SARS-CoV-2, suggesting sailent points for expanding future research.


2021 ◽  
Vol 13 (13) ◽  
pp. 7217
Author(s):  
Zhen Liu ◽  
Jing Liu ◽  
Mohamed Osmani

Circular economy (CE) is a concept actively advocated by the European Union (EU), China, Japan, and the United Kingdom. At present, CE is considered to grant the most traction for companies to achieve sustainable development. However, CE is still rarely adopted by enterprises. As the backbone of the fourth industrial revolution, the digital economy (DE) is considered to have a disruptive effect. Studies have shown that digital technology has great potential in promoting the development of CE. Especially during the COVID-19 epidemic that has severely negatively affected the global economy, environment, and society, CE and DE are receiving high attention from policy makers, practitioners, and scholars around the world. However, the integration of CE and digital technology is a small and rapidly developing research field that is still in its infancy. Although there is a large amount of research in the fields of CE and DE, respectively, there are few studies that look into integrating these two fields. Therefore, the purpose of this paper is to explore the research progress and trends of the integration of CE and DE, and provide an overview for future research. This paper adopts a bibliometric research method, employs the Web of Science database as its literature source, and uses VOSviewer visual software to carry out keyword co-occurrence analysis, which focuses on publication trends, journal sources, keyword visualization, multidisciplinary areas, life cycle stages, and application fields.


2021 ◽  
pp. 135481662199996
Author(s):  
Ali Salman Saleh ◽  
Charbel Bassil ◽  
Arsalan Safari

Tourism in the Gulf Cooperation Council (GCC) countries has recently been considered by policymakers as a new avenue for economic diversification. Despite the considerable literature concerning the impact of tourism worldwide, only a limited number of studies have looked at the tourism sector in the GCC region or analyzed its economic, sociocultural, and environmental impacts. This article therefore conducts a systematic review of the state of the literature related to tourism in the GCC region. It provides effective insights about the current status, gaps, and challenges and proposes future research directions in this area for academics, practitioners, and policymakers with an interest in regional tourism development. The preferred reporting items for systematic reviews and meta-analyses approach was used to identify and select the papers. Some 23 papers were identified and analyzed. The majority of these studies focused on the United Arab Emirates, specifically the Dubai emirate. We found the most dominant research theme to be tourism planning.


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