The actinobacteria Streptomyces wadayamensis A23, an endophitic strain, was recently sequenced and previous work showed qualitatively that the strain inhibits the growth of some pathogens. Herein we report the genome analysis of S. wadayamensis which reveals several antibiotic biosynthetic pathways. Using mass spectrometry, we were able to identify desferoxamines, several antimycins and candicidin, as predicted. Additionally, it was possible to confirm that the biosynthetic machinery of the strain when compared to identified known metabolites is far underestimated. As suggested by biochemical qualitative tests, genome encoded information reveals that the strain A23 has high capability to produce antibiotics.

Polyketides and non-ribosomal peptides are natural products widely found in bacteria, fungi and plants. The biological activities associated with these metabolites have attracted special attention in biopharmaceutical studies. Polyketide synthases act similarly to fatty acids synthetases and the whole multi-enzymatic set coordinating precursor and extending unit selection and reduction levels during chain growth. Acting in a similarly orchestrated model, non-ribosomal peptide synthetases biosynthesize NRPs. PKSs-I and NRPSs enzymatic modules and domains are collinearly organized with the parent gene sequence. This arrangement allows the use of degenerated PCR primers to amplify targeted regions in the genes corresponding to specific enzymatic domains such as ketosynthases and acyltransferases in PKSs and adenilation domains in NRPSs. Careful analysis of these short regions allows the classifying of a set of organisms according to their potential to biosynthesize PKs and NRPs. In this work, the biosynthetic potential of a set of 13 endophytic actinobacteria from Citrus reticulata for producing PKs and NRP metabolites was evaluated. The biosynthetic profile was compared to antimicrobial activity. Based on the inhibition promoted, 4 strains were considered for cluster analysis. A PKS/NRPS phylogeny was generated in order to classify some of the representative sequences throughout comparison with homologous genes. Using this approach, a molecular fingerprint was generated to help guide future studies on the most promising strains.

Two endophytic strains of Methylobacterium spp. were used to evaluate biofilm formation on sugarcane roots and on inert wooden sticks. Results show that biofilm formation is variable and that plant surface and possibly root exudates have a role in Methylobacterium spp. host recognition, biofilm formation and successful colonization as endophytes.

The colonization of Spodoptera frugiperda J.E. Smith larvae and rice seedlings by genetically modified endophytic bacterium Methylobacterium mesophilicum, and also the possible transfer of this bacterium to inside the larva's body during seedlings consumption were studied. The data obtained by bacterial reisolation and fluorescence microscopy showed that the bacterium colonized the rice seedlings, the larva's body and that the endophytic bacteria present in seedlings could be acquired by the larvae. In that way, the transference of endophytic bacterium from plants to insect can be a new and important strategy to insect control using engineered microorganisms.