Tools for genetic manipulation of the plant growth-promoting bacterium Azospirillum amazonense

Abstract

Background: Azospirillum amazonense has potential to be used as agricultural inoculant since it promotes plant growth without causing pollution, unlike industrial fertilizers. Owing to this fact, the study of this species has gained interest. However, a detailed understanding of its genetics and physiology is limited by the absence of appropriate genetic tools for the study of this species. Results: Conjugation and electrotransformation methods were established utilizing vectors with broad hostreplication origins (pVS1 and pBBR1). Two genes of interest - glnK and glnB, encoding PII regulatory proteins - were isolated. Furthermore, glnK-specific A. amazonense mutants were generated utilizing the pK19MOBSACB vector system. Finally, a promoter analysis protocol based on fluorescent protein expression was optimized to aid genetic regulation studies on this bacterium. Conclusion: In this work, genetic tools that can support the study of A. amazonense were described. These methods could provide a better understanding of the genetic mechanisms of this species that underlie its plant growth promotion.