Natural genetic variation in Arabidopsis for responsiveness to plant growth-promoting rhizobacteria

• Published in: Plant molecular biology 2016-04, Vol.90 (6), p.623-634
• Main Authors: Wintermans, Paul C. A, Bakker, Peter A. H. M, Pieterse, Corné M. J
• Format: Article
• Language: English
• Subjects: Arabidopsis; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - microbiology; Arabidopsis thaliana; Bacteria; Biochemistry; Biomedical and Life Sciences; breeding; Correlation analysis; crops; Gene Expression Regulation, Plant; genes; Genetic diversity; Genetic Variation; Genome-Wide Association Study; growth promotion; Life Sciences; loci; microbiome; Organic compounds; Plant biology; Plant growth; plant growth-promoting rhizobacteria; Plant Pathology; Plant Roots - genetics; Plant Roots - microbiology; Plant Sciences; Plant Shoots - genetics; Plant Shoots - growth & development; Polymorphism, Single Nucleotide; Population genetics; Pseudomonas; Pseudomonas - physiology; Rhizobium; Rhizosphere; roots; shoots; Soil microorganisms; Symbiosis; VOCs; Volatile organic compounds
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/s11103-016-0442-2

The plant growth-promoting rhizobacterium (PGPR) Pseudomonas simiae WCS417r stimulates lateral root formation and increases shoot growth in Arabidopsis thaliana (Arabidopsis). These plant growth-stimulating effects are partly caused by volatile organic compounds (VOCs) produced by the bacterium. Here, we performed a genome-wide association (GWA) study on natural genetic variation in Arabidopsis for the ability to profit from rhizobacteria-mediated plant growth-promotion. To this end, 302 Arabidopsis accessions were tested for root architecture characteristics and shoot fresh weight in response to exposure to WCS417r. Although virtually all Arabidopsis accessions tested responded positively to WCS417r, there was a large variation between accessions in the increase in shoot fresh weight, the extra number of lateral roots formed, and the effect on primary root length. Correlation analyses revealed that the bacterially-mediated increase in shoot fresh weight is related to alterations in root architecture. GWA mapping for WCS417r-stimulated changes in root and shoot growth characteristics revealed 10 genetic loci highly associated with the responsiveness of Arabidopsis to the plant growth-promoting activity of WCS417r. Several of the underlying candidate genes have been implicated in important plant growth-related processes. These results demonstrate that plants possess natural genetic variation for the capacity to profit from the plant growth-promoting function of a beneficial rhizobacterium in their rhizosphere. This knowledge is a promising starting point for sustainable breeding strategies for future crops that are better able to maximize profitable functions from their root microbiome.