Abstract
The recent worldwide discovery of plant growth-promoting (PGP) Kosakonia radicincitans in a large variety of crop plants suggests that this species confers significant influence on plants, both in terms of yield increase and product quality improvement. We provide a comparative genome analysis which helps to unravel the genetic basis for K. radicincitans' motility, competitiveness and plant growth-promoting capacities. We discovered that K. radicincitans carries multiple copies of complex gene clusters, among them two flagellar systems and three type VI secretion systems (T6SSs). We speculate that host invasion may be facilitated by different flagella, and bacterial competitor suppression by effector proteins ejected via T6SSs. We found a large plasmid in K. radicincitans DSM 16656T, the species type strain, that confers the potential to exploit plant-derived carbon sources. We propose that multiple copies of complex gene clusters in K. radicincitans are metabolically expensive but provide competitive advantage over other bacterial strains in nutrient-rich environments. The comparison of the DSM 16656T genome to genomes of other genera of enteric plant growth-promoting bacteria (PGPB) exhibits traits unique to DSM 16656T and K. radicincitans, respectively, and traits shared between genera. We used the output of the in silico analysis for predicting the purpose of genomic features unique to K. radicincitans and performed microarray, PhyloChip, and microscopical analyses to gain deeper insight into the interaction of DSM 16656T, plants and associated microbiota. The comparative genome analysis will facilitate the future search for promising candidates of PGPB for sustainable crop production.
Highlights
Among the approaches to achieve food security and the sustainable handling of resources, one of the most promising is considered the tailored application of microorganismbased inoculants in agriculture, with an expected compound annual growth rate of 9% during 2015–2020 on a global scale
A category summarizing plant growth-promoting (PGP) genes does not exist in the applied functional classification tools (RAST from SEED and BlastKOALA from KEGG), but summing up the coding sequences (CDS) allocated to PGP we found 243 genes (= 4.4% of the genome) of K. radicincitans DSM 16656T (Table 1)
We considered the consistency of these two gene clusters in K. radicincitans to reflect important functions and asked the three following questions: (1) Why has K. radicincitans two flagellar systems? (2) Does K. radicincitans affect the natural microbiota of plants? (3) How and where is K. radicincitans colonizing the plant?
Summary
Among the approaches to achieve food security and the sustainable handling of resources, one of the most promising is considered the tailored application of microorganismbased inoculants in agriculture, with an expected compound annual growth rate of 9% during 2015–2020 on a global scale (http://www.researchandmarkets.com/reports/3786558). Plant-associated microorganisms have proven to protect their hosts from pathogens and herbivores, providing efficient supplements of, or alternatives to pesticides, while other microorganisms were shown to increase nutrient availability, promoting plant growth and yield. Over the past two decades effort has been made to explore the association between so-called plant growth-promoting bacteria (PGPB) and nonleguminous plants for producing agricultural inoculants made from bacteria. Being the three most produced cereals of the world and accounting for approximately two-thirds of human food consumption, maize, rice and wheat are of particular interest for the application of PGPB. Root nodulecolonizing rhizobia (= plant development-enhancing strains of family Rhizobiaceae) and filamentous Actinobacteria from genus Frankia, many enteric PGPB, strains from genera Enterobacter, Klebsiella and Kosakonia, are able to colonize a wide range of hosts. “Alcedo”) and selected putatively plant growth-promoting strains. In the course of this reclassification E. radicincitans was renamed Kosakonia radicincitans
Sign-in/Register to view highlights & summary 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 callDisclaimer: 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.
