RESUMEN
The present work aimed to characterize rhizobia nodulating Trigonella foenum-graecum L. (fenugreek) cultivated in six different geographical locations in Northwestern Morocco. Forty-seven rhizobial isolates from nodules of Trigonella foenum-graecum were grouped into thirteen clusters using the Rep-PCR technique. The phylogenetic analysis based on 16S rRNA gene sequences of 13 groups showed that all representative strains were closely related to members of the genus Ensifer (syn. Sinorhizobium) of the Alphaproteobacteria. All the representative strains shared 100% similarity with Ensifer medicae WSM419T. NodC and nifH gene analysis revealed a close phylogenetic relationship of the representative strains with those of the strains belonging to the symbiovar meliloti. Furthermore, nodulation ability of our rhizobial strains was efficient in their host plant (Trigonella foenum-graecum L.).
Asunto(s)
Rhizobium , Trigonella , ADN Bacteriano/genética , Variación Genética , Marruecos , Filogenia , ARN Ribosómico 16S/genética , Rhizobium/genética , Nódulos de las Raíces de las Plantas/microbiología , Análisis de Secuencia de ADN , Simbiosis/genéticaRESUMEN
Seventy bacterial strains were isolated from root nodules of the legume Hedysarum flexuosum grown wild in soils from Northwest Morocco. Repetitive extragenic palindromic (REP)-polymerase chain reaction (PCR) clustered the strains into 30 REP-PCR groups. The nearly complete sequence of the 16S rRNA gene from a representative strain of each REP-PCR pattern showed that 17 strains were closely related to members of the genus Rhizobium of the family Rhizobiaceae of the Alphaproteobacteria. Pairwise alignments between globally aligned sequences of the 16S rRNA gene indicated that the strains from H. flexuosum had 99.75-100% identity with Rhizobium sullae type strain IS123(T). The phenotypic characteristics analyzed allowed description of a wide physiological diversity among the isolates, where the carbohydrate assimilation test was the most discriminating. Analysis of the 16S rRNA gene of a representative strains from the remaining 13 REP-PCR groups showed they belong to a wide variety of phylogenetic groups being closely related to species of genera Stenotrophomonas, Serratia, Massilia, Acinetobacter, Achromobacter, and Pseudomonas from the Beta- and Gammaproteobacteria. The R. sullae strains identified in this study produced effective symbiosis with their original host plant. None of the other bacterial strains could form nodules on H. flexuosum.
Asunto(s)
Bacterias/clasificación , Bacterias/aislamiento & purificación , Fabaceae/microbiología , Fenotipo , Rhizobium/clasificación , Rhizobium/genética , Nódulos de las Raíces de las Plantas/microbiología , Bacterias/genética , ADN Bacteriano , Genes de ARNr , Variación Genética , Marruecos , Filogenia , Reacción en Cadena de la Polimerasa , ARN Ribosómico 16S/genética , Rhizobium/aislamiento & purificación , Alineación de Secuencia , SimbiosisRESUMEN
OBJECTIVES: Plasmid mediated quinolone resistance (PMQR) genes are increasingly detected worldwide. However, in Morocco a few studies have been carried out. The aim of this study was to investigate the prevalence of these determinants among Escherichia coli and Klebsiella spp. isolated from North-West of Morocco. METHODS: The prevalence of PMQR genes was investigated among 398 E. coli and 118 Klebsiella spp. clinical isolates collected between 2012 and 2015 from North-West of Morocco. Antimicrobial susceptibility was determined by disc diffusion assay and minimal inhibitory concentrations (MIC) of quinolone were determined by micro-dilution. The screening of qnrA, qnrB, qnrC qnrS, Aac(6')-Ib and qepA genes were done by PCR, DNA sequencing and RFLP analyses. RESULTS: Among 398 E. coli and 118 Klebsiella spp. analyzed, 51% of E. coli and 61% of Klebsiella spp. were multidrug resistant (MDR). For the E. coli group, qnrB, qnrS, and aac(6')-Ib-cr genes were detected in 05.02%, 01.50%, and 13.81%, respectively. These determinants were more prevalent in Klebsiella spp. group, hence they represented 11.86%, 05.93% and 18.64% respectively. QnrA, qnrC and qepA were absent in this study. For aac(6')Ib determinant, 84.41% were belong to the Aac(6') Ib-cr variant while for qnrB and qnrS the most determined variants were qnrB1, B6, B16, B42, B66 and qnrS1, S4, S7. Different plasmid sizes were detected in PMQR strains. CONCLUSION: This is the first study conducted in North-West of Morocco and shows important dissemination of MDR and PMQR among Enterobacteriaceae.