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Anne M Alvarez - One of the best experts on this subject based on the ideXlab platform.
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Seed-associated subspecies of the genus Clavibacter are clearly distinguishable from Clavibacter michiganensis subsp. michiganensis.
International journal of systematic and evolutionary microbiology, 2014Co-Authors: Jarred Yasuhara-bell, Anne M AlvarezAbstract:The genus Clavibacter contains one recognized species, Clavibacter michiganensis. Clavibacter michiganensis is subdivided into subspecies based on host specificity and bacteriological characteristics, with Clavibacter michiganensis subsp. michiganensis causing bacterial canker of tomato. Clavibacter michiganensis subsp. michiganensis is often spread through contaminated Seed leading to outbreaks of bacterial canker in tomato production areas worldwide. The frequent occurrence of non-pathogenic Clavibacter michiganensis subsp. michiganensis-like bacteria (CMB) is a concern for Seed producers because Clavibacter michiganensis subsp. michiganensis is a quarantine organism and detection of a non-pathogenic variant may result in destruction of an otherwise healthy Seed lot. A thorough biological and genetic characterization of these Seed-associated CMB strains was performed using standard biochemical tests, cell wall analyses, metabolic profiling using Biolog, and single-gene and multilocus sequence analyses. Combined, these tests revealed two distinct populations of Seed-associated members of the genus Clavibacter that differed from each other, as well as from all other described subspecies of Clavibacter michiganensis. DNA-DNA hybridization values are 70 % or higher, justifying placement into the single recognized species, C. michiganensis, but other analyses justify separate subspecies designations. Additionally, strains belonging to the genus Clavibacter isolated from pepper also represent a distinct population and warrant separate subspecies designation. On the basis of these data we propose subspecies designations for separate non-pathogenic subpopulations of Clavibacter michiganensis: Clavibacter michiganensis subsp. californiensis subsp. nov. and Clavibacter michiganensis subsp. chilensis subsp. nov. for Seed-associated strains represented by C55(T) ( = ATCC BAA-2691(T) = CFBP 8216(T)) and ZUM3936(T) ( = ATCC BAA-2690(T) = CFBP 8217(T)), respectively. Recognition of separate subspecies is essential for improved international Seed Testing operations.
R H Morrison - One of the best experts on this subject based on the ideXlab platform.
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sampling in Seed health Testing
Phytopathology, 1999Co-Authors: R H MorrisonAbstract:ABSTRACT Seed health tests are usually performed on a sample of a Seed lot; therefore, it is crucial that the test sample be as homogeneous as possible and representative of the lot. Seed sampling procedures appropriate for Seed health Testing have been developed by Seed Testing organizations such as the International Seed Testing Association and the Association of Official Seed Analysts. Seed lot size is generally not a constraint when the distribution of contaminated/infected Seed in the lot is relatively homogeneous; if the distribution is heterogeneous, increased sampling intensity is required. Sample size is determined by the damage threshold (intolerable infection level) for the pathogen and the probability of detection desired, commonly 95 or 99%. The probability of detection at a given damage threshold is greater as sample size increases, and this probability and the appropriate sample size can be determined by statistical methods. Most Seed health tests utilize qualitative data based on the presence or absence of the pathogen in the test sample, with the lot being rejected if the pathogen is detected in the sample and accepted if the sample is negative.
Jarred Yasuhara-bell - One of the best experts on this subject based on the ideXlab platform.
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Seed-associated subspecies of the genus Clavibacter are clearly distinguishable from Clavibacter michiganensis subsp. michiganensis.
International journal of systematic and evolutionary microbiology, 2014Co-Authors: Jarred Yasuhara-bell, Anne M AlvarezAbstract:The genus Clavibacter contains one recognized species, Clavibacter michiganensis. Clavibacter michiganensis is subdivided into subspecies based on host specificity and bacteriological characteristics, with Clavibacter michiganensis subsp. michiganensis causing bacterial canker of tomato. Clavibacter michiganensis subsp. michiganensis is often spread through contaminated Seed leading to outbreaks of bacterial canker in tomato production areas worldwide. The frequent occurrence of non-pathogenic Clavibacter michiganensis subsp. michiganensis-like bacteria (CMB) is a concern for Seed producers because Clavibacter michiganensis subsp. michiganensis is a quarantine organism and detection of a non-pathogenic variant may result in destruction of an otherwise healthy Seed lot. A thorough biological and genetic characterization of these Seed-associated CMB strains was performed using standard biochemical tests, cell wall analyses, metabolic profiling using Biolog, and single-gene and multilocus sequence analyses. Combined, these tests revealed two distinct populations of Seed-associated members of the genus Clavibacter that differed from each other, as well as from all other described subspecies of Clavibacter michiganensis. DNA-DNA hybridization values are 70 % or higher, justifying placement into the single recognized species, C. michiganensis, but other analyses justify separate subspecies designations. Additionally, strains belonging to the genus Clavibacter isolated from pepper also represent a distinct population and warrant separate subspecies designation. On the basis of these data we propose subspecies designations for separate non-pathogenic subpopulations of Clavibacter michiganensis: Clavibacter michiganensis subsp. californiensis subsp. nov. and Clavibacter michiganensis subsp. chilensis subsp. nov. for Seed-associated strains represented by C55(T) ( = ATCC BAA-2691(T) = CFBP 8216(T)) and ZUM3936(T) ( = ATCC BAA-2690(T) = CFBP 8217(T)), respectively. Recognition of separate subspecies is essential for improved international Seed Testing operations.
Felipe Siverio - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the efficacy of immunomagnetic separation for the detection of clavibacter michiganensis subsp michiganensis in tomato Seeds
Journal of Applied Microbiology, 2008Co-Authors: L De Leon, A Rodriguez, M M Lopez, Felipe SiverioAbstract:Aims: To evaluate the effectiveness of the optimized immunomagnetic separation (IMS)-plating protocol in relation to other culture, serological and molecular techniques currently used for Clavibacter michiganensis subsp. michiganensis in Seed-Testing laboratories. Methods and results: Bacterial suspensions, tomato Seed extracts spiked with the pathogen and naturally infected Seeds were IMS-plated for the detection of C. m. subsp. michiganensis. These results were compared with plating on general (YPGA) and semiselective (mSCM) media, double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), immunofluorescent assay (IF) or polymerase chain reaction (PCR). Different Seed lots and pathogen strains were also tested. IMS-plating allowed the detection of less than 10 CFU ml−1 of pathogen in all assayed samples. The mSCM medium provided positive results for 10 CFU ml−1 in naturally infected Seeds, but up to 14 days was necessary for the typical colonies of the target to be come visible. By serological techniques, 103 and up to 104 CFU ml−1 were detected by IF and ELISA, respectively. DNA extraction was required to obtain positive results by PCR in Seed extracts containing 103 CFU ml−1 or more. Conclusions: Among the evaluated methods, IMS-plating provided the best results regarding sensitivity and specificity for C. m. subsp. michiganensis detection, allowing the recovery of viable bacteria from Seed extracts. Significance and impact of the study: IMS-plating increases isolation rates of C. m. subsp. michiganensis and could improve standard protocols currently used for routine analysis.
L De Leon - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the efficacy of immunomagnetic separation for the detection of clavibacter michiganensis subsp michiganensis in tomato Seeds
Journal of Applied Microbiology, 2008Co-Authors: L De Leon, A Rodriguez, M M Lopez, Felipe SiverioAbstract:Aims: To evaluate the effectiveness of the optimized immunomagnetic separation (IMS)-plating protocol in relation to other culture, serological and molecular techniques currently used for Clavibacter michiganensis subsp. michiganensis in Seed-Testing laboratories. Methods and results: Bacterial suspensions, tomato Seed extracts spiked with the pathogen and naturally infected Seeds were IMS-plated for the detection of C. m. subsp. michiganensis. These results were compared with plating on general (YPGA) and semiselective (mSCM) media, double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), immunofluorescent assay (IF) or polymerase chain reaction (PCR). Different Seed lots and pathogen strains were also tested. IMS-plating allowed the detection of less than 10 CFU ml−1 of pathogen in all assayed samples. The mSCM medium provided positive results for 10 CFU ml−1 in naturally infected Seeds, but up to 14 days was necessary for the typical colonies of the target to be come visible. By serological techniques, 103 and up to 104 CFU ml−1 were detected by IF and ELISA, respectively. DNA extraction was required to obtain positive results by PCR in Seed extracts containing 103 CFU ml−1 or more. Conclusions: Among the evaluated methods, IMS-plating provided the best results regarding sensitivity and specificity for C. m. subsp. michiganensis detection, allowing the recovery of viable bacteria from Seed extracts. Significance and impact of the study: IMS-plating increases isolation rates of C. m. subsp. michiganensis and could improve standard protocols currently used for routine analysis.