Kosakonia Radicincitans Research Articles

A Proteomic Approach Suggests Unbalanced Proteasome Functioning Induced by the Growth-Promoting Bacterium Kosakonia radicincitans in Arabidopsis.

Endophytic plant growth-promoting bacteria have significant impact on the plant physiology and understanding this interaction at the molecular level is of particular interest to support crop productivity and sustainable production systems. We used a proteomics approach to investigate the molecular mechanisms underlying plant growth promotion in the interaction of Kosakonia radicincitans DSM 16656 with Arabidopsis thaliana. Four weeks after the inoculation, the proteome of roots from inoculated and control plants was compared using two-dimensional gel electrophoresis and differentially abundant protein spots were identified by liquid chromatography tandem mass spectrometry. Twelve protein spots were responsive to the inoculation, with the majority of them being related to cellular stress reactions. The protein expression of 20S proteasome alpha-3 subunit was increased by the presence of K. radicincitans. Determination of proteasome activity and immuno blotting analysis for ubiquitinated proteins revealed that endophytic colonization interferes with ubiquitin-dependent protein degradation. Inoculation of rpn12a, defective in a 26S proteasome regulatory particle, enhanced the growth-promoting effect. This indicates that the plant proteasome, besides being a known target for plant pathogenic bacteria, is involved in the establishment of beneficial interactions of microorganisms with plants.

Identification and Whole Genome Sequencing of the First Case of Kosakonia radicincitans Causing a Human Bloodstream Infection.

The taxonomy of Enterobacter species is rapidly changing. Herein we report a bloodstream infection isolate originally identified as Enterobacter cloacae by Vitek2 methodology that we found to be Kosakonia radicincitans using genetic means. Comparative whole genome sequencing of our isolate and other published Kosakonia genomes revealed these organisms lack the AmpC β-lactamase present on the chromosome of Enterobacter sp. A fimbriae operon primarily found in Escherichia coli O157:H7 isolates was present in our organism and other available K. radicincitans genomes. This is the first report of a Kosakonia species, which are typically associated with plants, causing a human infection.

Antagonistic effects of biofilm-forming bacterial strains co-inoculated with blood disease pathogenic strain, Ralstonia syzygii subspecies celebesensis in banana plants

A blood disease pathogenic strain, Ralstonia syzygii subspecies celebesensis was used to study the possible association of biofilm-forming bacteria with the development and severity of blood disease in banana plants. Therefore, the objective of this study was to determine the effects of mono-culture and co-culture inoculation of isolated biofilm-forming bacteria with the blood disease pathogen in banana pseudostems in glasshouse conditions. Putative biofilm-forming bacteria were isolated from an infected banana plant and were further identified using 16SrRNA sequencing. Four isolates, identified as Enterobacter hormaechei, Enterobacter cloacae, Kosakonia radicincitans and Klebsiella pneumoniae, were inoculated as a mono- and co-culture with R. syzygii subsp. celebesensis into 2 months old banana plants. The observation after the 8 weeks of post inoculation showed that plants which were co-inoculated with the pathogen and K. radicincitans, a biofilm-forming bacterium, were the most susceptible towards the infection. In contrast, plants under two treatments (which were co-inoculated with the pathogen and E. cloacae and the pathogen with E. hormaechei) were less susceptible towards the infection. This study revealed the antagonistic effects of two biofilm-forming strains which reduced the severity of infection caused by the pathogenic agent. Scanning electron micrographs of the cross section of plant rhizomes indicated the dissimilarity of adhesion and host colonization conditions of the pathogen in each infected plant from different treatments.

Kosakonia pseudosacchari sp. nov., an endophyte of Zea mays

A beige pigmented bacterial strain (JM-387T), isolated from field-grown corn root tissue, Tallassee, Alabama, was studied for its taxonomic allocation. A comparison of the 16S rRNA gene sequence with those of the type strains of most closely related species of the family Enterobacteriaceae showed highest sequence similarities to the type strain of Kosakonia sacchari (99.5%), “Enterobacter oryzendophyticus” (98.8%), and Kosakonia radicincitans (98.6%).Construction of phylogenetic trees based on the 16S rRNA gene and partial sequences of four protein-coding genes, rpoB, gyrB, infB, and atpD (multilocus sequence analysis, MLSA) showed a distinct clustering of strain JM-387T with Kosakonia sacchari. DNA-DNA hybridizations between JM-387T and the type strains of most similar Kosakonia/“Enterobacter” species including K. sacchari LMG 26783T, “E. oryzendophyticus” LMG 26432T, K. radicincitans D5/23T, K. oryzae LMG 24251T, E. cancerogenus LMG 2693T, and E. cloacae subsp. dissolvens CCUG 25230T were in the range of 14.4–60.2%. The average nucleotide identity (ANI) of the genome sequence of the new strain to K. sacchari SP1T was 94.47%.Strain JM-387T had a typical enterobacterial fatty acid pattern consisting of the major fatty acids C16:0, C16:1 ω7c/C16:1 ω6c/C15:0 2OH, C18:1 ω7c/C18:1 ω6c with C14:0 3-OH as hydroxylated fatty acid.Genotypic data and the differentiating biochemical and chemotaxonomic properties showed that strain JM-387T represents a novel species of the genus Kosakonia, for which the name Kosakonia pseudosacchari sp. nov. (type strain JM-387T=CIP 110597T=DSM 27151T) is proposed.

K. radicincitans, a beneficial bacteria that promotes radish growth under field conditions

Conserving arable soils is a major challenge in agronomy. Using beneficial native microorganisms such as plant growth-promoting bacteria contributes to sustainability in agricultural systems and helps maintain stable yields and product quality. However, the growth-promoting effects of candidate strains observed in pot trials often disappear under field conditions. Therefore, we studied here the bacterial colonization of Kosakonia radicincitans, a known plant growth-promoting bacteria, and the effect of K. radicincitans on radish. We measured plant growth and glucosinolate profile when plants were grown under glasshouse and field conditions. K. radicincitans cells were applied onto seeds or plants when two leaves had emerged. Our results show an increase of up to 25 % of leaf and tuber weights of inoculated radish plants under glasshouse and field conditions, compared to non-inoculated plants. Glucosinolate contents remained unchanged, except when leaves were sprayed with K. radicincitans. We also found that K. radicincitans suppressed aromatic 2-phenylethyl glucosinolates in leaves. To sum up, we demonstrate for the first time the capability of K. radicincitans to persist and promote plant growth in a member of the Brassicaceae family under field conditions. Therefore, K. radicincitans is a promising candidate for further processing as a growth-promoting product in sustainable agriculture.

Bio-inoculation of yerba mate seedlings (Ilex paraguariensis St. Hill.) with native plant growth-promoting rhizobacteria: a sustainable alternative to improve crop yield

In this study, the role of native plant growth-promoting rhizobacteria (PGPR) as bio-inoculants was assessed as an alternative to ameliorate Ilex paraguariensis St. Hill. growth in nursery comparing poorer (soil) versus richer (compost) substrates. Twelve rhizospheric strains isolated from yerba mate plantations were evaluated in vitro for their potential as PGPRs. Three isolates, identified as Kosakonia radicincitans YD4, Rhizobium pusense YP3, and Pseudomonas putida YP2, were selected on the basis of their N2 fixation activity, IAA-like compound and siderophore production, and phosphate solubilization. A highly significant positive effect of bio-inoculation with the native isolates was observed in 5-month-old seedlings cultivated in soil. The highest increase was observed in seedlings inoculated with K. radicincitans YD4 with an increase of 183 % in the dry shoot weight and a 30 % increase in shoot N content. In contrast, in compost, no increment in the dry weight was observed; however, an increase in content in some macronutrients in shoots was observed. Remarkably, when plant biomass was compared between soil and compost, seedlings inoculated with K. radicincitans YD4 in soil produced the highest yields, even though higher yields could be expected in compost due to the richness of this substrate. In conclusion, bio-inoculation of yerba mate seedlings with native PGPR increases the yield of this crop in nursery and could represent a promising sustainable strategy to improve yerba mate growth in low-fertility soils.

Genome Sequence of Kosakonia radicincitans Strain YD4, a Plant Growth-Promoting Rhizobacterium Isolated from Yerba Mate (Ilex paraguariensis St. Hill.).

Kosakonia radicincitans strain YD4 is a rhizospheric isolate from yerba mate (Ilex paraguariensis St. Hill.) with plant growth-promoting effects on this crop. Genes involved in different plant growth-promoting activities are present in this genome, suggesting its potential as a bioinoculant for yerba mate.

Genome sequence of Kosakonia radicincitans UMEnt01/12, a bacterium associated with bacterial wilt diseased banana plant.

Kosakonia radicincitans (formerly known as Enterobacter radicincitans), an endophytic bacterium was isolated from the symptomatic tissues of bacterial wilt diseased banana (Musa spp.) plant in Malaysia. The total genome size of K. radicincitans UMEnt01/12 is 5 783 769 bp with 5463 coding sequences (CDS), 75 tRNAs, and 9 rRNAs. The annotated draft genome of the K. radicincitans UMEnt01/12 strain might shed light on its role as a bacterial wilt-associated bacterium.

Taxonomic evaluation of the genus Enterobacter based on multilocus sequence analysis (MLSA): Proposal to reclassify E. nimipressuralis and E. amnigenus into Lelliottia gen. nov. as Lelliottia nimipressuralis comb. nov. and Lelliottia amnigena comb. nov., respectively, E. gergoviae and E. pyrinus into Pluralibacter gen. nov. as Pluralibacter gergoviae comb. nov. and Pluralibacter pyrinus comb. nov., respectively, E. cowanii, E. radicincitans, E.

The taxonomy of Enterobacter has a complicated history, with several species transferred to and from this genus. Classification of strains is difficult owing to its polyphyletic nature, based on 16S rRNA gene sequences. It has been previously acknowledged that Enterobacter contains species which should be transferred to other genera. In an attempt to resolve the taxonomy of Enterobacter, MLSA based on partial sequencing of protein-encoding genes (gyrB, rpoB, infB and atpD) was performed on the type strains and reference strains of Enterobacter, Cronobacter and Serratia species, as well as members of the closely related genera Citrobacter, Klebsiella, Kluyvera, Leclercia, Mangrovibacter, Raoultella and Yokenella. Phylogenetic analyses of the concatenated nucleotide sequences revealed that Enterobacter can be divided into five strongly supported MLSA groups, suggesting that the species should be reclassified into five different genera. Further support for this was provided by a concatenated amino acid tree, phenotypic characteristics and fatty acid profiles, enabling differentiation of the MLSA groups. Three novel genera are proposed: Lelliottia gen. nov., Pluralibacter gen. nov. and Kosakonia gen. nov. and the following new combinations: Lelliottia nimipressuralis comb. nov., Lelliottia amnigena comb. nov., Pluralibacter gergoviae comb. nov., Pluralibacter pyrinus comb. nov., Kosakonia cowanii comb. nov., Kosakonia radicincitans comb. nov., Kosakonia oryzae comb. nov., Kosakonia arachidis comb. nov., Cronobacter helveticus comb. nov. and Cronobacter pulveris comb. nov. Additionally, the novel epithet Cronobacter zurichensis nom. nov. is proposed for the reclassification of Enterobacter turicensis into the genus Cronobacter, as Cronobacter turicensis (Iversen et al., 2008) is already in use.