Similarities and differences between various creatures are used to classify them. Those with similar characteristics are included in the same category. Starting with prokaryotes, azospirillum is categorised fundamentally. Bacteria and archaea are the two domains of the prokaryotic groupings. Proteobacteria, gram-positive bacteria and nonproteobacteria gram-negative bacteria are further members of the domain bacteria. Alphaproteobacteria, deltaproteobacteria, gammaproteobacteria, epsilon proteobacteria and beta proteobacteria are the five different kinds of proteobacteria. The alpha-proteobacteria group includes azospirillum. Alphaproteobacteria are known for their unique morphologies and ability to flourish at extremely low nutrition levels (stalks or buds).