Isolation and characterization of endophytic streptomycete antagonists of fusarium wilt pathogen from surface-sterilized banana roots

Abstract

A total of 131 endophytic actinomycete strains were successfully isolated from surface-sterilized banana roots. These isolates belonged to Streptomyces (n=99), Streptoverticillium (n=28), and Streptosporangium (n=2) spp. The remaining 2 isolates were not identified. About 18.3% of the isolates inhibited the growth of pathogenic Fusarium oxysporum f. sp. cubense on banana tissue extract medium. The most frequently isolated Streptomyces sp. strain S96 was similar to Streptomyces griseorubiginosus. About 37.5% of the S. griseorubiginosus strains were antagonistic to F. oxysporum f. sp. cubense. The antagonism of strain S96 was lost when FeCl(3) was introduced into the inhibition zone. In vivo biocontrol assays showed that the disease severity index (DSI) was significantly (P=0.05) reduced and mean fresh weight increased (P=0.001) in plantlets treated with strain S96 compared to those grown in the absence of the biocontrol strain. These findings indicate the potential of developing siderophore-producing Streptomyces endophytes for the biological control of fusarium wilt disease of banana.

A New Approach to Analyzing Endophytic Actinobacterial Population in the Roots of Banana Plants (Musa sp., AAA)

“…The actinobacterial taxa were not consistent with previous results. Streptomyces was the most frequently isolated genus from surface-sterilized banana roots [7] , nevertheless, it can not be isolated or detected in previous studies [1,6,22] . In the study, total 11 reads belonged to Streptomyces or Streptomycetaceae were detected by Illumina-based analysis.…”

“…The actinobacteria are rich source of biologically active natural products and are widely distributed in different terrestrial and marine habitats [8] , their growth rates were lower than other endophyic bacteria and fungi [7] . The previous culture-dependent and culture-independent methods based on E. coli 16S rRNA gene might underestimate the diversity of endophytic actinobacteria.…”

“…Endophytic non-filamentous actinobacteria had been isolated from growing shoot tips of banana [5,6] . Although the healthy-promoting roles of filamentous actinobacteria were widely accepted [7] , the diversity of actinobacteria among the banana root microbiota is still poorly understand.…”

Isolamento, armazenamento e determinação da colonização por fungos “dark septate” a partir de plantas de arroz

“…Após o período de incubação foram visualizados pouco mais de 100 colônias fúngicas e praticamente não se verificou a presença de bactérias, o que mostra que a suplementação do meio ágar-malte com antibióticos restringiu a contaminação bacteriana e favoreceu a recuperação e a purificação dos isolados de DSEF. O uso de antibióticos no meio de cultura faz-se necessário, pois muitas bactérias presentes nas raízes atuam como antagonista de fungos, não permitindo o seu crescimento (CAO et al, 2005;SILVANI et al, 2008). A suplementação do meio ágar-malte com outros antibióticos como a cloromicetina também tem mostrado eficiência para o isolamento de fungos endofíticos a partir das raízes de outras espécies de Oryza.…”

Distribution and Identification of Endophytic Streptomyces Species from Schima wallichii as Potential Biocontrol Agents against Fungal Plant Pathogens

“…Endophytes acquired a specific ability that allows them to sustain under the living tissues without any detectable infectious symptoms to the host. Thus, they are of immense importance to the host due to their capability to produce a wide array of natural bioactive compounds (Sardi et al, 1992;Strobel and Daisy, 2003;Cao et al, 2005;Kim et al, 2012).…”