Bacteria Associated with the Roots of Common Bean (Phaseolus vulgaris L.) at Different Development Stages: Diversity and Plant Growth Promotion

Abstract

Current agricultural methodologies are vulnerable to erratic climate and are dependent on cost-intensive fertilization to ensure high yields. Sustainable practices should be pursued to ensure food security. Phaseolus vulgaris L. is one of the most produced legumes worldwide and may be an alternative to reduce the environmental impact of meat production as a reliable source of high-quality protein. Plant growth-promoting rhizobacteria (PGPR) are emerging as a sustainable option to increase agricultural production. To understand the dynamics between plants and microorganisms, the culturable microbiota of bean roots was isolated and identified at distinct stages of plant development (early and late vegetative growth, flowering, and pod) and root compartments (rhizoplane, endosphere, and nodules). Diversity and abundance of bacteria associated with root compartments differed throughout the plant life cycle. Bacterial plant growth promotion (PGP) and protection abilities (indole-3-acetic acid production, siderophore synthesis, and antifungal activity) were assessed and associated with plant phenology, demonstrating that among the bacteria associated with plant roots, several strains had an active role in the response to plant biological needs at each stage. Several strains stood out for their ability to display one or more PGP traits, being excellent candidates for efficient stage-specific biostimulants for application in precision agriculture.

The elite common beanPhaseolus vulgariscultivar Pinto Saltillo hosts a rich and diverse array of plant-growth promoting bacteria in its rhizosphere

“…To the best of our knowledge, these genera have also been found in different high-throughput studies but not in the microbiome of Phaseolus vulgaris (23). However, Rocha et al (63) recently reported a plethora of cultivated PGPR in the rhizosphere of Phaseolus vulgaris L., variety “Patareco,” in agreement with the metagenomic PGPR registered in this study.…”

“…In the rhizosphere of the Pinto Saltillo cultivar, abundance at the genus level indicated that a group of Promoter-Growth Plant Rhizobacteria plays an important role (63). Consistently, the genera Pseudomonas , Rhizobium , Pantoea , and Variovorax were the most abundant in the rhizosphere of the cultivar Pinto Saltillo.…”