Abstract
In the search for new organisms and new secondary metabolites, a study was conducted to evaluate the diversity of endophytic bacteria from ethnovarieties of cassava cultivated by Brazilian Amazon Indian tribes and also to study the secondary metabolites produced by a Bacillus pumilus strain. Sixty seven cassava endophytic bacteria were subjected to 16S rRNA sequencing and FAME analysis. The bacterial profile revealed that 25% of all endophytic isolates belonged to the genus Bacillus. The isolate B. pumilus MAIIIM4a showed a strong inhibitory activity against the fungi Rhizoctonia solani, Pythium aphanidermatum and Sclerotium rolfsii. Secondary metabolites of this strain were extracted using hexane, dichloromethane and ethyl acetate. Extracts were subjected to bioautography and LC/MS analysis, which allowed the identification of pumilacidin, an antifungal compound produced by B. pumilus MAIIIM4a. The bacterial endophytic localization was confirmed by cassava cell tissue examination using scanning electron microscopy.
Highlights
Endophytes are microorganisms that inhabit a wide variety of plant tissue types without causing any apparent harm to the host (Hallmann et al, 1997)
The resulting profiles were identified with microbial identification software (MIDI) using the TSBA database, version 4.0 (MIDI, Newark, Del.) and a dendrogram can be visualized in Figure 1 (Teixeira, 2004)
The bootstrap analysis based on 1,000 resamplings of the neighbour-joining data, used to test the robustness and stability of the branching, showed that the B. pumilus strains sequences clustered with high bootstrap value (98%) separated from the other species of Bacillus
Summary
Endophytes are microorganisms (bacterial and fungal) that inhabit a wide variety of plant tissue types without causing any apparent harm to the host (Hallmann et al, 1997). In order to colonize the plant and compete with other microorganisms, they produce many enzymes and toxins (Lima et al, 2005). A variety of secondary metabolites, including enzymes, antibiotics (Pleban et al, 1997), anticancer (Stierle et al, 1993), anti-inflammatory (Trischman et al, 1994), antifungal (Korzybski et al, 1978), and biological control agents (Hallmann et al, 1997) have been isolated from endophytic microorganisms. Most of them produce enzymes and antibiotics as the main action mechanisms.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
