Molecular and biochemical characterization of Xanthomonas axonopodis pv. citri pathotypes (original) (raw)
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Background: Xanthomonas axonopodis or X. axonopdis is the devastating causal organism of citrus canker, widely spread bacterial disease of plants from both epidemiological and economic points of view. Furthermore, the situation is worsening by the advent of increased antibiotic resistance among this bacteria. The major interests of this study were isolation, identification and in vitro antibiotic sensitivity pattern of the causal organism. Besides, herbal sensitivity of those organisms was also tested. Methods: In this study, 9 isolates of the organism were identified based on morphological, cultural and biochemical characteristics. All the isolates were tested for antibiotic sensitivity against 5 commonly used antibiotics namely, cefotaxime, bacitracin, chloramphenicol, streptomycin and gentamycin.
Citrus has an important value as fruit crop. Present day citrus is delectable, juicy, and seedless is of great nutritional significance as well, additionally, it possesses enormous therapeutic qualities. Citrus canker caused by Xanthomonas axonopodis pv.citri is a damaging disease of acid lime. The bacterium infects the twigs, petioles, fruit stalks and fruits, resulting in both qualitative and quantitative loss in acid lime. The isolations and identification were made from the symptomatic samples collected from different districts, viz. Ahmednagar (XacI), Pune (XacII), solapur (XacIII), Nashik (XacIV), Belgaum (XacV), and grouped as per agro-ecological zones. The growth characteristics of all the isolates were studied on nutrient agar medium.Through morphological, biochemical and pathogenicity test isolates were identified and confirmed as Xanthomonas axonopodis pv.citri.The variability was studied among the five isolates of Xac by using 14 RAPD and 08 ISSR primers.Level of polymorphism was 100%. The RAPD UPGMA analysis showed that the isolate Xac III (Solapur) was found to have higher value of similarity coefficient (0.4000) with Xac V (Balgaon) whereas Xac I (Ahmednagar) was found to have lower value of similarity coefficient (0.1304) with Xac II (Pune), and for the ISSR UPGMA analysis showed that the isolate Xac II (Pune) was found to have higher value of similarity coefficient (1.000) with Xac V (Balgaon) whereas Xac I (Ahmednagar) was found to have lower value of similarity coefficient (0.00) with Xac II (Pune).Efficacy of different combination of chemicals, oils against Xanthomonas axonopodis pv. citri was assessed in vitro by measuring the growth by paper disc method and turbidiometrically method. Maximum zone of inhibition was recorded in chemical treatments. i.e. bronopol ranges from 18-26 mm zone of inhibition. Among the oils clove oil (18mm) exhibited maximum zone of inhibition followed by Eucalyptus oil (14 mm) in 5µl concentration by paper disc diffusion method.The antibiotic sensitivity against Xanthomonas axonopodis pv. citri was tested using seven Hi-media hexa discs The causal pathogen Xanthomonas axonopodis pv. citri showed sensitivity to most of the antibiotic tested. Antibiotic Ofloxacin (OF) (5mg) showed maximum zone of inhibition (39mm), following Norfloxacin (NX) (10mg), Levofoxacin (LE) (5mg) showed zone of inhibition (35mm) (35mm) respectively. However, resistant of antibiotics i.e., Aztreonam (AT), Cefuroximeaxetil (CXM) observed against Xac.
Pak. J. Phytopathol, 2007
Fifteen citrus cultivars were screened for the sources of resistance against citrus canker disease incited by Xanthomonas axonopodis pv. citri in a field trial conducted at research area of plant pathology department for two years i.e. 2005-07. Citrus sinensis cv. jaffa exhibited resistant response while Citrus paradise, Citrus sinensis cv. blood red, Citrus limonia cv. mayer lemon showed highly susceptible expression. Citrus sinensis cv. valentia late, Citrus reticulate cv. feutral's early showed moderately resistant while Citrus reticulate cv. malta, Citrus limettioides, Citrus limonia cv. china lemon, Citrus sinensis cv. musambi were found moderately susceptible towards canker disease. No citrus cultivar was found immune.
Xanthomonas axonopodis pv. citri: factors affecting successful eradication of citrus canker
Molecular plant pathology, 2004
SUMMARY Taxonomic status: Bacteria, Proteobacteria, gamma subdivision, Xanthomodales, Xanthomonas group, axonopodis DNA homology group, X. axonopodis pv. citri (Hasse) Vauterin et al. Microbiological properties: Gram negative, slender, rod-shaped, aerobic, motile by a single polar flagellum, produces slow growing, non-mucoid colonies in culture, ecologically obligate plant parasite. Host range: Causal agent of Asiatic citrus canker on most Citrus spp. and close relatives of Citrus in the family Rutaceae. Disease symptoms: Distinctively raised, necrotic lesions on fruits, stems and leaves. Epidemiology: Bacteria exude from lesions during wet weather and are disseminated by splash dispersal at short range, windblown rain at medium to long range and human assisted movement at all ranges. Crop loss: Severe infections cause defoliation, blemished fruit, premature fruit drop, die-back of twigs and general debilitation of the tree. Distribution: Citrus canker is not present in all subtropi...
Journal of Applied Microbiology, 2007
Aims: To show the results of the detection of an EU quarantine organism, Xanthomonas axonopodis pv. citri (Xac), in citrus fruits imported from countries where this bacterium is present, using an integrated approach that includes isolation, pathogenicity assays and molecular techniques.Methods and Results: Citrus fruits with canker-like symptoms, exported to Spain from South American countries were analysed by several methods. Bacterial isolation, three conventional polymerase chain reaction (PCR) protocols, and real-time PCR with SYBR Green or a TaqMan probe, were compared. Canker-like lesions were disrupted in PBS buffer, and the extract used for bacterial isolation and DNA extraction followed by PCR amplification. Canker lesions, identified by PCR, showed viable bacteria in eleven of fifteen fruit samples. In 16 out of 130 lesions analysed from these samples, Xac was isolated, and pathogenicity on grapefruit leaves confirmed. By real-time PCR, using SYBR green or a Taqman probe, Xac was detected in 58 and 80 lesions respectively. By conventional PCR the bacterium was detected in 39–52 lesions depending on the protocol employed.Conclusions: An integrated approach for reliable detection of Xac in lesions of fruit samples, employing several techniques and with real-time PCR using a TaqMan probe as the fastest and most sensitive screening method, has been established and validated and is proposed as a useful tool for the analysis of Xac on fresh fruits.Significance and Impact of the Study: This work faces up to the real threat of the importation of citrus fruits that can harbour quarantine bacteria and will be useful in diagnostic laboratories for the analysis of commercial fresh fruits from countries where citrus canker is present.
Molecular plant pathology, 2018
Taxonomic status: Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Order Xanthomonadales; Family Xanthomonadaceae; Genus Xanthomonas; Species Xanthomonas citri ssp. citri (Xcc). Host range: Compatible hosts vary in their susceptibility to citrus canker (CC), with grapefruit, lime and lemon being the most susceptible, sweet orange being moderately susceptible, and kumquat and calamondin being amongst the least susceptible. Microbiological properties: Xcc is a rod-shaped (1.5-2.0 × 0.5-0.75 µm), Gram-negative, aerobic bacterium with a single polar flagellum. The bacterium forms yellow colonies on culture media as a result of the production of xanthomonadin. Distribution: Present in South America, the British Virgin Islands, Africa, the Middle East, India, Asia and the South Pacific islands. Localized incidence in the USA, Argentina, Brazil, Bolivia, Uruguay, Senegal, Mali, Burkina Faso, Tanzania, Iran, Saudi Arabia, Yemen and Bangladesh. Widespread throughout Paraguay, Como...
The present study is based on biochemical characterization, pathogenicity test and DNA based technique. Here apart from biochemical test, RAPD analysis was used to distinguish and differentiate among 24 strains of Xac isolated from Marathwada region in Maharashtra. 200 strains of Xac isolated from Citrus lemona from different location within Marathwada region of Maharashtra and 24 strains representing all the 8 districts were used in this study. All these strains were purified and maintained on YDC (Yeast extract-1gm, D-glucose-2gm, Calcium carbonate-2gm) slants. The presently used primer could resolve genetic diversity and geographical distribution in the study of Xanthomonas axonopodis pv citri and RAPD marker gave reproducible and reliable results.
Ecology, Environment and Conservation
Bacterial canker is one of the most common citrus diseases, causing widespread losses throughout the citrus growing regions of the world, including India. Madhya Pradesh is one among the leading states in India for citrus production. Therefore, to Keep track of the disease prevalence on lime, lemon, malta, grapefruit, and other citrus fruits, a survey was conducted in eastern (Baghelkhand) and northern (Gird) regions of Madhya Pradesh during the months of February to March 2022. Various crucial data were collected on disease severity (percentage) and disease incidence (percentage). During the survey, disease incidence was recorded from 0% to 40% range, and disease severity from 0% to 37%, with a maximum mean disease incidence (36.5%) and severity (34%), respectively, in Chinor tahsil of Gwalior district and a minimum disease incidence (18%) and severity (17.3%) in Satna district of Madhya Pradesh. Disease samples of Xanthomonas axonopodis pv.citri were collected from various village...
Applied and Environmental Microbiology, 2002
Partial sequence analysis of the ribosomal operon in Xanthomonas axonopodis allowed discrimination among strains causing the A, B, and C types of citrus bacterial canker (CBC) and quantification of the relationship of these organisms with other species and pathovars in the same genus. Sets of primers based on sequence differences in the internally transcribed spacer and on a sequence from the plasmid gene pthA involved in virulence were designed for specific identification of xanthomonads causing CBC diseases. The two sets were validated with a collection of Xanthomonas strains associated with citrus species. The primer set based on ribosomal sequences had a high level of specificity for X. axonopodis pv. citri, whereas the set based on the pthA gene was universal for all types of CBC organisms. Moreover, the relationships among worldwide Xanthomonas strains causing CBC were analyzed by amplification of repetitive sequences (enterobacterial repetitive intergenic consensus and BOX el...