RESUMO
The production of bioethanol and sugar from sugarcane is an important economic activity in several countries. Sugarcane is susceptible to different phytopathogens. Over the last years, the red stripe disease caused by the bacterium Acidovorax avenae subsp. avenae produced significant losses in sugarcane crops. Bio-nanotechnology emerged as an eco-friendly alternative to the biosynthesis of antimicrobial molecules. The aims of this study were to (a) produce extracellular silver nanoparticles using the heavy metal resistant strain Amycolatopsis tucumanensis, (b) evaluate their antibacterial in vitro effect and (c) determine the potential of silver nanoparticles to protect sugarcane against red stripe disease. Amycolatopsis tucumanensis synthesized spherical silver nanoparticles with an average size of 35 nm. Nanoparticles were able to control the growth of A. avenae subsp. avenae in in vitro assays. In addition, in vivo assays in sugarcane showed a control upon the red stripe disease when silver nanoparticles were applied as preventive treatment. The Disease Severity Index was 28.94% when silver nanoparticles were applied 3 days before inoculation with A. avenae subsp. a venae. To our knowledge, this is the first report of silver nanoparticles extracellularly synthesized by an Amycolatopsis strain that were able to inhibited the growth of A. avenae subsp. avenae and control the red stripe disease in sugarcane.
RESUMO
Through the years, the genus Amycolatopsis has demonstrated its biotechnological potential. The need to clean up the environment and produce new antimicrobial molecules led to exploit promising bacterial genera such as Amycolatopsis. In this present work, we analyze the genome of the strain Amycolatopsis tucumanensis AB0 previously isolated from copper-polluted sediments. Phylogenomic and comparative analysis with the closest phylogenetic neighbor was performed. Our analysis showed the genetic potential of the strain to deal with heavy metals such as copper and mitigate oxidative stress. In addition, the ability to produce copper oxide nanoparticles and the presence of genes potentially involved in the synthesis of secondary metabolites suggest that A. tucumanensis may find utility in gray, red, and nano-biotechnology. To our knowledge, this is the first genomic analysis of an Amycolatopsis strain with potential for different biotechnological fields.
Assuntos
Actinomycetales , Cobre , Amycolatopsis , Cobre/metabolismo , DNA Bacteriano/genética , Genômica , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Old Yellow Enzymes play key roles in several cellular processes and have become an important family of enzymes with biotechnological potential. One of the major challenges of biotechnology consists of the bioremediation of co-polluted soils with organic and inorganic compounds. In co-contaminated areas, chromium normally exists in its more toxic and carcinogenic form Cr(VI). Microorganisms can reduce this metal to the insoluble and less toxic Cr(III). Streptomyces sp. M7 is a strain able to efficiently bioremediate polluted soils with γ-hexachlorocyclohexane and Cr(VI). The complete degradation pathway for γ-hexachlorocyclohexane was recently elucidated in this strain. In the present work, we confirmed the ability of Streptomyces sp. M7 to eliminate a high percentage of Cr(VI) from a synthetic culture medium. After a transcriptional study in the presence of Cr(VI), we also report the molecular cloning of a gene coding for an Old Yellow Enzyme with chromate reductase activity. Our results suggest that the elimination of Cr(VI) by Streptomyces sp. M7 is directly related to the activity of this Old Yellow Enzyme. The importance of our work is in identifying for the first time an Old Yellow Enzyme with chromate reductase activity in Streptomyces and Actinobacteria. Finding this enzyme helps understand chromium homeostasis in Streptomyces sp. M7, in addition to opening a new research window related to Old Yellow Enzymes from Actinobacteria.