Abstract

BackgroundBacillus amyloliquefaciens SQR9 is a plant growth-promoting rhizobacteria (PGPR) with outstanding abilities to enhance plant growth and to control soil-borne diseases. Root exudates is known to play important roles in plant-microbe interactions. To explore the rhizosphere interactions and plant-beneficial characteristics of SQR9, the complete genome sequence as well as the transcriptome in response to maize root exudates under biofilm-forming conditions were elucidated.ResultsMaize root exudates stimulated SQR9 biofilm formation in liquid culture, which is known to be positively correlated with enhanced root colonization. Transcriptional profiling via RNA-sequencing of SQR9 under static conditions indicated that, at 24 h post-inoculation, root exudates stimulated the expression of metabolism-relevant genes, while at 48 h post-inoculation, genes related to extracellular matrix production (tapA-sipW-tasA operon) were activated by root exudates. The individual components in maize root exudates that stimulated biofilm formation included glucose, citric acid, and fumaric acid, which either promoted the growth of SQR9 cells or activated extracellular matrix production. In addition, numerous groups of genes involved in rhizosphere adaptation and in plant-beneficial traits, including plant polysaccharide utilization, cell motility and chemotaxis, secondary antibiotics synthesis clusters, and plant growth promotion-relevant, were identified in the SQR9 genome. These genes also appeared to be induced by the maize root exudates.ConclusionsEnhanced biofilm formation of B. amyloliquefaciens SQR9 by maize root exudates could mainly be attributed to promoting cell growth and to inducing extracellular matrix production. The genomic analysis also highlighted the elements involved in the strain’s potential as a PGPR. This study provides useful information for understanding plant-rhizobacteria interactions and hence for promoting the agricultural applications of this strain.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1825-5) contains supplementary material, which is available to authorized users.

Highlights

  • Bacillus amyloliquefaciens SQR9 is a plant growth-promoting rhizobacteria (PGPR) with outstanding abilities to enhance plant growth and to control soil-borne diseases

  • Complete genome sequencing of several plant-associated Bacillus amyloliquefaciens strains, including FZB42, CAU B946, and YAU B9601-Y2, have revealed functional genes involved in growth promotion and disease control [4,5,6,7]

  • The results of this study reveal the genetic basis of rhizosphere adaption and plant beneficial effects of SQR9, which are crucial for understanding plant-rhizobacteria interactions and improving the application of this strain in agriculture

Read more

Summary

Introduction

Bacillus amyloliquefaciens SQR9 is a plant growth-promoting rhizobacteria (PGPR) with outstanding abilities to enhance plant growth and to control soil-borne diseases. Plant growth-promoting rhizobacteria (PGPR) are a group of rhizosphere-colonizing bacteria that can promote plant growth and control soil-borne diseases, which are of great importance in both basic and applied microbiology [1, 2]. Flavonoids secreted by roots of leguminous plants are known to play an important role in the early signaling events of legume-rhizobia interactions [12]; while organic acids, such as malic acid and citric acid, in root exudates recruit Bacillus strains in the rhizosphere [15, 16]

Methods
Results
Discussion
Conclusion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.