Unexpected Phytostimulatory Behavior for <i>Escherichia coli</i> and <i>Agrobacterium tumefaciens</i> Model Strains

Walker, Vincent; Bruto, Maxime; Bellvert, Floriant; Bally, René; Müller, Daniel; Prigent‐Combaret, Claire; Moënne‐Loccoz, Yvan; Comte, Gilles

doi:10.1094/mpmi-12-12-0298-r

Cited by 22 publications

(21 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although it shares nearly identical circular and linear chromosomes with the pathogenic A. tumefaciens C58, RrF4 is non-pathogenic. As shown previously, and consistent with our finding, curing C58 from its pTi plasmid results in a non-pathogenic strain with albeit weak plant growth-stimulating activity (Walker et al, 2013). Nevertheless, at present, we do not know all the factors needed by RrF4 to associate with its fungal host P. indica.…”

Section: Resultssupporting

confidence: 79%

Non-pathogenic Rhizobium radiobacter F4 deploys plant beneficial activity independent of its host Piriformospora indica

et al. 2015

View full text Add to dashboard Cite

The Alphaproteobacterium Rhizobium radiobacter F4 (RrF4) was originally characterized as an endofungal bacterium in the beneficial endophytic Sebacinalean fungus Piriformospora indica. Although attempts to cure P. indica from RrF4 repeatedly failed, the bacterium can easily be grown in pure culture. Here, we report on RrF4's genome and the beneficial impact the free-living bacterium has on plants. In contrast to other endofungal bacteria, the genome size of RrF4 is not reduced. Instead, it shows a high degree of similarity to the plant pathogenic R. radiobacter (formerly: Agrobacterium tumefaciens) C58, except vibrant differences in both the tumor-inducing (pTi) and the accessor (pAt) plasmids, which can explain the loss of RrF4's pathogenicity. Similar to its fungal host, RrF4 colonizes plant roots without host preference and forms aggregates of attached cells and dense biofilms at the root surface of maturation zones. RrF4-colonized plants show increased biomass and enhanced resistance against bacterial leaf pathogens. Mutational analysis showed that, similar to P. indica, resistance mediated by RrF4 was dependent on the plant's jasmonate-based induced systemic resistance (ISR) pathway. Consistent with this, RrF4-and P. indica-induced pattern of defense gene expression were similar. In clear contrast to P. indica, but similar to plant growth-promoting rhizobacteria, RrF4 colonized not only the root outer cortex but also spread beyond the endodermis into the stele. On the basis of our findings, RrF4 is an efficient plant growth-promoting bacterium.

show abstract

Section: Resultssupporting

confidence: 79%

Non-pathogenic Rhizobium radiobacter F4 deploys plant beneficial activity independent of its host Piriformospora indica

et al. 2015

View full text Add to dashboard Cite

show abstract

“…As shown previously, and consistent with our finding, curing C58 from its pTi plasmid results in a nonpathogenic strain with albeit weak plant growth-stimulating activity (Walker et al 2013). Nevertheless, at present we do not know all the factors needed by RrF4 to associate with its fungal host P. indica.…”

Section: Analysis Of the Rrf4 Genomesupporting

confidence: 79%

Detection and Characterization of Endobacteria in the Fungal Endophyte Piriformospora indica

Glaeser

Alabid

Guo

et al. 2017

Modern Tools and Techniques to Understand Microbes

View full text Add to dashboard Cite

The nonpathogenic Alphaproteobacterium Rhizobium radiobacter (syn. Agrobacterium tumefaciens) (RrF4) is a subculture of the endobacterium R. radiobacter, which is intricately associated with its host, the beneficial plantcolonizing fungal basidiomycete Piriformospora indica. RrF4 is genetically very similar to the well-studied plant pathogenic R. radiobacter biovar I strain C58 (genomovar G8). Highly similar genetic content of RrF4 and C58 denotes the high potential for RrF4 to directly interact with plants. The failure to cure P. indica from its endobacterium still hampers a conclusive prediction of the bacterium's extended role in the interaction of the fungus with a broad spectrum of host plants. However, beneficial activities shown in cereals and the Brassicaceae Arabidopsis thaliana were hardly distinguishable when induced either by RrF4 or P. indica. We discuss here the various strategies employed to detect, characterize, and eventually elucidate the endobacterium's role in the tripartite symbiosis with its fungal host and a plant.

show abstract

“…Several taxa associated with suppressive soils in this study can have plant protecting and/or plant‐growth promoting properties, e.g. Agrobacterium , Azospirillum , Gluconacetobacter , Sphingomonadaceae and Methylobacterium (Adhikari et al ., ; Kennedy et al ., ; Russo et al ., ; Poorniammal et al ., ; Walker et al ., ), and they merit further assessment for T. basicola biocontrol. Even though their actual contribution to black root rot control is not known yet, the corresponding probes may be useful as indicators.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of rhizobacterial indicators of tobacco black root rot suppressiveness in farmers' fields

Kyselková

Almario

Kopecký

et al. 2014

Environ Microbiol Rep

Self Cite

View full text Add to dashboard Cite

Very few soil quality indicators include disease-suppressiveness criteria. We assessed whether 64 16S rRNA microarray probes whose signals correlated with tobacco black root rot suppressiveness in greenhouse analysis could also discriminate suppressive from conducive soils under field conditions. Rhizobacterial communities of tobacco and wheat sampled in 2 years from four farmers' fields of contrasted suppressiveness status were compared. The 64 previously identified indicator probes correctly classified 72% of 29 field samples, with nine probes for Azospirillum, Gluconacetobacter, Sphingomonadaceae, Planctomycetes, Mycoplasma, Lactobacillus crispatus and Thermodesulforhabdus providing the best prediction. The whole probe set (1033 probes) revealed strong effects of plant, field location and year on rhizobacterial community composition, and a smaller (7% variance) but significant effect of soil suppressiveness status. Seventeen additional probes correlating with suppressiveness status in the field (noticeably for Agrobacterium, Methylobacterium, Ochrobactrum) were selected, and combined with the nine others, they improved correct sample classification from 72% to 79% (100% tobacco and 63% wheat samples). Pseudomonas probes were not informative in the field, even those targeting biocontrol pseudomonads producing 2,4-diacetylphloroglucinol, nor was quantitative polymerase chain reaction for 2,4-diacetylphloroglucinol-synthesis gene phlD. This study shows that a subset of 16S rRNA probes targeting diverse rhizobacteria can be useful as suppressiveness indicators under field conditions.

show abstract

Unexpected Phytostimulatory Behavior for Escherichia coli and Agrobacterium tumefaciens Model Strains

Cited by 22 publications

References 55 publications

Non-pathogenic Rhizobium radiobacter F4 deploys plant beneficial activity independent of its host Piriformospora indica

Non-pathogenic Rhizobium radiobacter F4 deploys plant beneficial activity independent of its host Piriformospora indica

Detection and Characterization of Endobacteria in the Fungal Endophyte Piriformospora indica

Evaluation of rhizobacterial indicators of tobacco black root rot suppressiveness in farmers' fields

Contact Info

Product

Resources

About