RESUMO
Astragalus cicer (cicer milkvetch) nodule bacteria were investigated for host plant specificity and partial nodC gene sequences, whilst their native host was studied for the microscopic structure of root nodules. The strains under investigation formed nodules not only on the original host but also on Astragalus glycyphyllos, Astragalus sinicus, Lotus corniculatus, and Phaseolus vulgaris. The nodules induced on the cicer milkvetch were classified as indeterminate and characterized by apical, persistent meristem, a large bacteroid region with infected and uninfected cells, and elongated bacteroids singly located inside peribacteroid membranes. By comparison of the partial nodC gene sequences of a representative strain of astragali rhizobia to those contained in the GenBank database, a close symbiotic relationship of A. cicer microsymbionts to Rhizobium sp. (Oxytropis) was found.
Assuntos
Fabaceae/microbiologia , N-Acetilglucosaminiltransferases/genética , Raízes de Plantas/microbiologia , Plantas Medicinais , Rhizobium/isolamento & purificação , Simbiose , Proteínas de Bactérias , Bacilos e Cocos Aeróbios Gram-Negativos/classificação , Bacilos e Cocos Aeróbios Gram-Negativos/genética , Bacilos e Cocos Aeróbios Gram-Negativos/isolamento & purificação , Filogenia , Raízes de Plantas/anatomia & histologia , Rhizobium/classificação , Rhizobium/genética , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
Thirty-seven rhizobium strains, isolated from root nodules of Astragalus cicer (L.) (cicer milkvetch) deriving from different geographic regions, were compared with the representative strains of the known rhizobial species and genera by numerical analysis of phenotypic characteristics. Our results indicated that Astragalus cicer rhizobia were related to the bacteria of Mesorhizobium species and formed two major phena. One phenon, localized on Mesorhizobium loti branch, contained strains from Poland. Another cluster, placed in the vicinity of M. tianshanense, M. mediterraneum, M. ciceri, and M. huakuii, comprised cicer milkvetch nodule isolates from Canada, Ukraine, and one strain from Poland. The relationship of Astragalus cicer microsymbionts to bacteria of the Mesorhizobium species was also supported by phage typing.
Assuntos
Fabaceae/microbiologia , Análise Numérica Assistida por Computador , Plantas Medicinais , Rhizobium/classificação , Antibacterianos/farmacologia , Tipagem de Bacteriófagos , Resistência Microbiana a Medicamentos , Fenótipo , Raízes de Plantas/microbiologia , Plasmídeos/análise , Rhizobium/efeitos dos fármacos , Rhizobium/fisiologia , SimbioseRESUMO
Three newly isolated phages, K1, K2, and C1, specific for A. cicer rhizobia were characterized by their morphology, host range, rate of adsorption, restriction endonuclease patterns, and DNA molecular weights. All three phages were classified to the morphological group B of Bradley's (Siphoviridae family) on the basis of presence of hexagonal in outline heads and long noncontractile tails. Phages K1, K2, and C1 are related by host range and restriction endonuclease patterns. The molecular weights of phage DNAs estimated from restriction enzyme digests were in the range from 64.6 kb to 68.5 kb.