Genetics and molecular biology of Azospirillum

Genetic manipulation of Azospirillum spp. has facilitated a better understa nding of the mode of action of this plant-growth promoting bacterium and sh ould help to improve its ability to stimulate plant growth and development. This review considers and discusses Agospirillum plasmids, promoter sequen ces, the isolation of Azospirillum mutants, the genetic transformation of A zospirillum the transfer of foreign genes into Azospirillum by conjugation and the Azospirillum genes that have been isolated and characterized. The A zospirillum genes that are discussed include genes involved in nitrogen fix ation: plant root attachment, phytohormone biosynthesis, tryptophan biosynt hesis, carbon metabolism and a few other less well characterized processes.