Microbial culture collections are very important components of biological science. They provide researchers
with material for studies and preserve biological resources. One such collection is the Collection of Rhizosphere
Microorganisms, kept at the Institute of Biochemistry and Physiology of Plants and Microorganisms of
the Russian Academy of Sciences, Saratov (IBPPM). Its activity is primarily directed toward the isolation and preservation
of microorganisms from the plant root zone. The international research interest in microorganisms from
this ecological niche is not waning, because they are very important for plant growth and development and, consequently,
for plant breeding. The group of bacteria with properties of significance for plants has been given the
name “plant-growth-promoting rhizobacteria” (PGPR). This group includes nitrogen-fixing soil alpha-proteobacteria
of the genus Azospirillum, which form the core of the IBPPM collection. First discovered by Brazilian scientists
in the 1970s, azospirilla are now a universally recognized model object for studying the molecular mechanisms
underlying plant-bacterium interactions. The broad range of useful properties found in these microorganisms,
including the fixation of atmospheric nitrogen, production of phytohormones, solubilization of phosphates, control
of pathogens, and formation of induced systemic resistance in the colonized plants, make these bacteria an
all-purpose tool that has been used for several decades in basic and applied research. This article reviews the
current state of Azospirillum research, with emphasis on the results obtained at the IBPPM. Scientific expeditions
across the Saratov region undertaken by IBPPM microbiologists in the early 1980s formed the basis for the unique
collection of members of this bacterial taxon. Currently, the collection has more than 160 Azospirillum strains and
is one of the largest collections in Europe. The research conducted at the IBPPM is centered mostly on the Azospirillum
structures involved in associative symbiosis with plants, primarily extracellular polysaccharide-containing
complexes and lectins. The development of immunochemical methods contributed much to our understanding
of the overall organization of the surface of rhizosphere bacteria. The extensive studies of the Azospirillum genome
largely deepened our understanding of the role of the aforesaid bacterial structures, motility, and biofilms in the
colonization of host plant roots. Of interest are also applied studies focusing on agricultural and environmental
technologies and on the “green” synthesis of Au, Ag, and Se nanoparticles. The Collection of Rhizosphere Microorganisms
continues to grow, being continually supplemented with newly isolated strains. The data presented in
this article show the great importance of specialized microbial culture repositories, such as the IBPPM collection,
for the development and maintenance of the microbial research base and for the effective solution of basic and
applied tasks in microbiology.
