Pseudomonas and Azospirillum

Abstract

Pseudomonas strains are fast growing, genetically diverse and metabolically versatile bacteria. Many pseudomonad species are preferential inhabitants of the rhizosphere of plants, reaching up to 10 8 CFU/g of roots for crop species like soybean or maize in the fi eld. Rhizospheric pseudomonads contribute to plant growth and health through a variety of plant probiotic mechanisms, including protection of roots against fungal pathogen attack. Due to their relative ease to isolate and cultivate in the lab, there is an enormous wealth of knowledge about physiological, biochemical, and genetic traits of pseudomonads. Based on their PGPR traits, several inoculant products are commercialized, either for seed, foliar, or postharvest treatment of crops, vegetables, and fruits. Provided that pseudomonads share the rhizosphere niche with Azospirillum species, as well as with many other PGPR microorganisms, combined formulations have also become available for agronomic purposes. However, little information about interspecies and multispecies interactions is available. This chapter describes microbiological, genetic, and agronomic tools that may be applied to isolate and characterize novel Pseudomonas spp. from diverse source materials, to study their interaction with Azospirillum cells in the context of dual or multispecies inoculants, and to evaluate the quality and effectiveness of formulated products.

Azospirillum baldaniorum Sp245 exploits Pseudomonas fluorescens A506 biofilm to overgrow in dual‐species macrocolonies

“…Rhizobacteria belonging to Azospirillum and fluorescent Pseudomonas groups have been extensively studied over the last decades due to the many benefits these microorganisms can exert on plant health (Vessey, 2003). This has led to their biotechnological exploitation as inoculants of agronomic use, mainly as single strain formulations but also as consortia (Valverde et al, 2015). However, research on Azospirillum‐Pseudomonas interaction dynamics has not been assessed until recently.…”

A novel, green, low-cost chitosan-starch hydrogel as potential delivery system for plant growth-promoting bacteria

“…brasilense and P. fluorescens can stimulate each other when cultivated together (Pagnussat et al, 2016) and are increasingly employed in combined inoculants as biofertilizers (Valverde, Gonzalez Anta, & Ferraris, 2015).…”