RESUMO
Clavibacter michiganensis is a Gram-stain-positive bacterium with eight subspecies. One of these subspecies is C. michiganensis subsp. michiganensis, which causes bacterial canker disease in tomato. Bacterial strains showing very similar canker disease symptoms to those of a strain originally classified as C. michiganensis have been isolated from pepper. In this paper, we reclassified strains isolated from pepper. On the basis of phylogenetic analysis with 16S rRNA gene sequences, the strains isolated from pepper were grouped in a separate clade from other subspecies of C. michiganensis. Biochemical, physiological and genetic characteristics of strain PF008T, which is the representative strain of the isolates from pepper, were examined in this study. Based on multi-locus sequence typing and other biochemical and physiological features including colony color, utilization of carbon sources and enzyme activities, strain PF008T was categorically differentiated from eight subspecies of C. michiganensis. Moreover, genome analysis showed that the DNA G+C content of strain PF008T is 73.2 %. These results indicate that PF008T is distinct from other known subspecies of C. michiganensis. Therefore, we propose a novel subspecies, C. michiganensis subsp. capsici, causing bacterial canker disease in pepper, with a type strain of PF008T (=KACC 18448T=LMG 29047T).
Assuntos
Capsicum/microbiologia , Micrococcaceae/classificação , Filogenia , Doenças das Plantas/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Micrococcaceae/genética , Micrococcaceae/isolamento & purificação , Tipagem de Sequências Multilocus , RNA Ribossômico 16S/genética , República da Coreia , Análise de Sequência de DNARESUMO
Heat treatment is commonly used to control viral contamination of seeds. To study virus inactivation, virus was purified from seeds contaminated with Cucumber green mottle mosaic virus (CGMMV) after various heat treatments. CGMMV particles were observed to be physically disrupted by high temperature. Analysis of viral RNA revealed that the 5' and 3' termini of the genome were protected whereas regions between 2-2.5, 3.2-3.7 and 4-4.8 kb from the 5' terminus were not. Heat inactivation of virus on seeds was confirmed by RT-PCR using primers for a heat-sensitive region. The RT-PCR approach developed here may prove preferable to time- and labor-intensive bioassays for assessing virus heat inactivation.
Assuntos
Cucumis sativus/virologia , Desinfecção/métodos , Temperatura Alta , Tobamovirus/metabolismo , Microscopia Eletrônica , Sementes/virologia , Tobamovirus/genéticaRESUMO
The nucleotide sequences of the genomic RNAs of Cucumber green mottle mosaic virus Korean watermelon isolate (CGMMV-KW) and Korean oriental melon isolate (CGMMV-KOM) were determined and compared to the sequences of other tobamoviruses including CGMMV strains W and SH. Each CGMMV isolate had a genome of 6,424 nucleotides. Each also had 60 and 176 nucleotides of 5' and 3' untranslated regions (UTRs), respectively, and four open reading frames (ORF1-4). ORFs 1 to 4 encode proteins of 129, 186, 29, and 17.4 kDa, respectively. The nucleotide and deduced amino acid sequences of CGMMV-KOM and CGMMV-KW were more than 98.3% identical. When compared to other CGMMV strains in a phylogenetic analysis they were found to form a distinct virus clade, and were more distantly related to other tobamoviruses (23.5-56.7% identity).
