Analysis of plant growth-promoting properties of Bacillus amyloliquefaciens UCMB5113 using Arabidopsis thaliana as host plant

• Published in: Planta Vol. 245; no. 1; pp. 15 - 30
• Main Authors: Asari, Shashidar, Tarkowská, Danuše, Rolčík, Jakub, Novák, Ondřej, Palmero, David Velázquez, Bejai, Sarosh, Meijer, Johan
• Format: Journal Article
• Language: English
• Published: Germany Springer Science + Business Media 01-01-2017; Springer Nature B.V
• Subjects: Acetic acid; Arabidopsis; Arabidopsis - drug effects; Arabidopsis - growth & development; Arabidopsis - microbiology; Arabidopsis thaliana; Bacillus amyloliquefaciens; Bacillus amyloliquefaciens - drug effects; Bacillus amyloliquefaciens - physiology; Botanik; Botany; Brassinosteroids - pharmacology; Crop production; Cytokinins - pharmacology; Environmental factors; Gibberellins - pharmacology; Host-Pathogen Interactions - drug effects; Indoleacetic Acids - pharmacology; Lipopeptides - pharmacology; ORIGINAL ARTICLE; Plant growth; Plant Growth Regulators - pharmacology; Plant Roots - anatomy & histology; Plant Roots - drug effects; Plant tissues; Rhizosphere; Root development; Roots; Seedlings - drug effects; Seedlings - growth & development; Sustainable agriculture; Sustainable production; Phytohormones; Root structure; Rhizosphere; Beneficial bacteria; Growth promotion; Biocontrol
• ISSN: 0032-0935; 1432-2048; 1432-2048
• DOI: 10.1007/s00425-016-2580-9

Root architecture plays a crucial role for plants to ensure uptake of water, minerals and nutrients and to provide anchorage in the soil. The root is a dynamic structure with plastic growth and branching depending on the continuous integration of internal and environmental factors. The rhizosphere contains a complex microbiota, where some microbes can colonize plant roots and support growth and stress tolerance. Here, we report that the rhizobacterium Bacillus amyloliquefaciens subsp. plantarum UCMB5113 stimulated the growth of Arabidopsis thaliana Col-0 by increased lateral root outgrowth and elongation and roothair formation, although primary root elongation was inhibited. In addition, the growth of the above ground tissues was stimulated by UCMB5113. Specific hormone reporter gene lines were tested which suggested a role for at least auxin and cytokinin signaling during rhizobacterial modulation of Arabidopsis root architecture. UCMB5113 produced cytokinins and indole-3-acetic acid, and the formation of the latter was stimulated by root exudates and tryptophan. The plant growth promotion effect by UCMB5113 did not appear to depend on jasmonic acid in contrast to the disease suppression effect in plants. UCMB5113 exudates inhibited primary root growth, while a semi-purified lipopeptide fraction did not and resulted in the overall growth promotion indicating an interplay of many different bacterial compounds that affect the root growth of the host plant. This study illustrates that beneficial microbes interact with plants in root development via classic and novel signals.