Caracterização taxonomica de actinomicetos endofiticos produtores de antibioticos isolados de cupuaçuzeiro (Theobroma grandiflorum Schum.) / Taxomnomic caracterization of endophytics actinomycetes producteurs of antibiotic cupuçu seeds isolated .

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Cupuaçu seeds (Theobroma grandiflorum) planted at the Universidade Federal do Amazonas (Manaus, AM, Brazil) were harvested after 15, 30, 45 and 60 days after germination and subjected to the isolation of endophytic bacteria. Fifty two endophytic actinomycetes were isolated from surface-sterilized leaves and roots using ISP 2 medium supplemented with starch, Starch-Casein and Raffinose-Histidine Agar, after incubation at 30° C. From these, seven isolates (13.5%) were obtained from leaves and 45 (86.5%) from roots. Antimicrobial activity in solid media was detected in 23 strains (44.2%), which were antagonistic for Bacillus subtilis (21.7%), Escherichia coli (17.4%), Staphylococcus aureus (39.1%), Candida albicans (30.4%) and Aspergillus flavus (17.4%), whereas only six isolates (11.5%) showed activity against Candida albicans when grown in liquid medium. Endophytic actinomycetes isolated from roots showed higher antimicrobial activity (87%) compared to isolates from leaves (13%). Taxonomic characterization showed that the majority of isolates recovered, 42 strains (80.8%), belonged to the genus Streptomyces. Restriction analysis of 16S rDNA fragments (ARDRA) using Alu I, Dde I, Hae III, Rsa I, Msp I, Sau3A I and Taq I enzymes revealed the presence of 17 different clusters among theses isolates. Phylogenetic analyses of 16S rDNA sequences suggest the existence of novel taxa amongst the endophytic streptomycetes strains recovered from cupuaçu seedlings.

ASSUNTO(S)

endofitico actinomicetos isolation taxonomia taxonomy isolamento endophytic cupuaçu actinomycetes

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