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Large scale transcriptome analysis reveals interplay between development of forest trees and a beneficial mycorrhiza helper bacterium.

Kurth F, Feldhahn L, Bönn M, Herrmann S, Buscot F, Tarkka MT - BMC Genomics (2015)

Bottom Line: To this end, we compared transcript profiles of oak microcuttings at RF and SF during interactions with AcH 505 alone and in combination with the basidiomycetous EMF Piloderma croceum.Treatment with AcH 505 induces and maintains the expression levels of signalling genes encoding candidate receptor protein kinases and TFs and leads to differential expression of cell wall modification related genes in pedunculate oak microcuttings.Local gene expression response to AcH 505 alone and in combination with P. croceum are more pronounced when roots are in resting stages, possibly due to the fact that non growing roots re-direct their activity towards plant defence rather than growth.

View Article: PubMed Central - PubMed

Affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, 06120, Halle/Saale, Germany. florence.kurth@ufz.de.

ABSTRACT

Background: Pedunculate oak, Quercus robur is an abundant forest tree species that hosts a large and diverse community of beneficial ectomycorrhizal fungi (EMFs), whereby ectomycorrhiza (EM) formation is stimulated by mycorrhiza helper bacteria such as Streptomyces sp. AcH 505. Oaks typically grow rhythmically, with alternating root flushes (RFs) and shoot flushes (SFs). We explored the poorly understood mechanisms by which oaks integrate signals induced by their beneficial microbes and endogenous rhythmic growth at the level of gene expression. To this end, we compared transcript profiles of oak microcuttings at RF and SF during interactions with AcH 505 alone and in combination with the basidiomycetous EMF Piloderma croceum.

Results: The local root and distal leaf responses to the microorganisms differed substantially. More genes involved in the recognition of bacteria and fungi, defence and cell wall remodelling related transcription factors (TFs) were differentially expressed in the roots than in the leaves of oaks. In addition, interaction with AcH 505 and P. croceum affected the expression of a higher number of genes during SF than during RF, including AcH 505 elicited defence response, which was attenuated by co-inoculation with P. croceum in the roots during SF. Genes encoding leucine-rich receptor-like kinases (LRR-RLKs) and proteins (LRR-RLPs), LRR containing defence response regulators, TFs from bZIP, ERF and WRKY families, xyloglucan cell wall transglycolases/hydrolases and exordium proteins were differentially expressed in both roots and leaves of plants treated with AcH 505. Only few genes, including specific RLKs and TFs, were induced in both AcH 505 and co-inoculation treatments.

Conclusion: Treatment with AcH 505 induces and maintains the expression levels of signalling genes encoding candidate receptor protein kinases and TFs and leads to differential expression of cell wall modification related genes in pedunculate oak microcuttings. Local gene expression response to AcH 505 alone and in combination with P. croceum are more pronounced when roots are in resting stages, possibly due to the fact that non growing roots re-direct their activity towards plant defence rather than growth.

No MeSH data available.


Related in: MedlinePlus

Pedunculate oak microcuttings with interacting microorganisms. Streptomyces sp. AcH 505 on soil particles in the microcosm (a) Piloderma croceum – oak ectomycorrhizas (b) and a pedunculate oak Quercus robur microcutting (c)
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Fig1: Pedunculate oak microcuttings with interacting microorganisms. Streptomyces sp. AcH 505 on soil particles in the microcosm (a) Piloderma croceum – oak ectomycorrhizas (b) and a pedunculate oak Quercus robur microcutting (c)

Mentions: Oak microcuttings were successfully inoculated with AcH 505 (Fig. 1). Three replicate RNA-Seq datasets were generated for microcutting lateral roots and leaves, during both RF and SF, following no inoculation, inoculation with AcH 505 and with both AcH 505 and P. croceum (n = 36; Additional files 1 and 2). For differential gene expression analysis, pairwise comparisons of datasets from plants inoculated with AcH 505 versus non-inoculated plants [differentially expressed contigs (DECs) in AcH 505 inoculated plants] and plants inoculated with AcH 505 and P. croceum versus non-inoculated plants [DECs in co-inoculated plants] were performed for roots and leaves at RF and SF respectively. The validity of the differential expression analyses was confirmed by qRT-PCR analysis (Additional file 3). Numbers of DECs among the samples are visualised in the Venn diagrams shown in Fig. 2 and tabulated in Additional file 4. AcH 505 treatment induced more DECs during SF than during RF in both roots and leaves. A suppressive effect by AcH 505-P. croceum co-inoculation on the numbers of DECs was evident during SF. Proportions of contigs regulated in AcH 505 inoculated plants which were also regulated when subjected to co-inoculation with P. croceum, were 33 in roots and 23 % in leaves during RF, and 5 and 3 % during SF.Fig. 1


Large scale transcriptome analysis reveals interplay between development of forest trees and a beneficial mycorrhiza helper bacterium.

Kurth F, Feldhahn L, Bönn M, Herrmann S, Buscot F, Tarkka MT - BMC Genomics (2015)

Pedunculate oak microcuttings with interacting microorganisms. Streptomyces sp. AcH 505 on soil particles in the microcosm (a) Piloderma croceum – oak ectomycorrhizas (b) and a pedunculate oak Quercus robur microcutting (c)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4557895&req=5

Fig1: Pedunculate oak microcuttings with interacting microorganisms. Streptomyces sp. AcH 505 on soil particles in the microcosm (a) Piloderma croceum – oak ectomycorrhizas (b) and a pedunculate oak Quercus robur microcutting (c)
Mentions: Oak microcuttings were successfully inoculated with AcH 505 (Fig. 1). Three replicate RNA-Seq datasets were generated for microcutting lateral roots and leaves, during both RF and SF, following no inoculation, inoculation with AcH 505 and with both AcH 505 and P. croceum (n = 36; Additional files 1 and 2). For differential gene expression analysis, pairwise comparisons of datasets from plants inoculated with AcH 505 versus non-inoculated plants [differentially expressed contigs (DECs) in AcH 505 inoculated plants] and plants inoculated with AcH 505 and P. croceum versus non-inoculated plants [DECs in co-inoculated plants] were performed for roots and leaves at RF and SF respectively. The validity of the differential expression analyses was confirmed by qRT-PCR analysis (Additional file 3). Numbers of DECs among the samples are visualised in the Venn diagrams shown in Fig. 2 and tabulated in Additional file 4. AcH 505 treatment induced more DECs during SF than during RF in both roots and leaves. A suppressive effect by AcH 505-P. croceum co-inoculation on the numbers of DECs was evident during SF. Proportions of contigs regulated in AcH 505 inoculated plants which were also regulated when subjected to co-inoculation with P. croceum, were 33 in roots and 23 % in leaves during RF, and 5 and 3 % during SF.Fig. 1

Bottom Line: To this end, we compared transcript profiles of oak microcuttings at RF and SF during interactions with AcH 505 alone and in combination with the basidiomycetous EMF Piloderma croceum.Treatment with AcH 505 induces and maintains the expression levels of signalling genes encoding candidate receptor protein kinases and TFs and leads to differential expression of cell wall modification related genes in pedunculate oak microcuttings.Local gene expression response to AcH 505 alone and in combination with P. croceum are more pronounced when roots are in resting stages, possibly due to the fact that non growing roots re-direct their activity towards plant defence rather than growth.

View Article: PubMed Central - PubMed

Affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, 06120, Halle/Saale, Germany. florence.kurth@ufz.de.

ABSTRACT

Background: Pedunculate oak, Quercus robur is an abundant forest tree species that hosts a large and diverse community of beneficial ectomycorrhizal fungi (EMFs), whereby ectomycorrhiza (EM) formation is stimulated by mycorrhiza helper bacteria such as Streptomyces sp. AcH 505. Oaks typically grow rhythmically, with alternating root flushes (RFs) and shoot flushes (SFs). We explored the poorly understood mechanisms by which oaks integrate signals induced by their beneficial microbes and endogenous rhythmic growth at the level of gene expression. To this end, we compared transcript profiles of oak microcuttings at RF and SF during interactions with AcH 505 alone and in combination with the basidiomycetous EMF Piloderma croceum.

Results: The local root and distal leaf responses to the microorganisms differed substantially. More genes involved in the recognition of bacteria and fungi, defence and cell wall remodelling related transcription factors (TFs) were differentially expressed in the roots than in the leaves of oaks. In addition, interaction with AcH 505 and P. croceum affected the expression of a higher number of genes during SF than during RF, including AcH 505 elicited defence response, which was attenuated by co-inoculation with P. croceum in the roots during SF. Genes encoding leucine-rich receptor-like kinases (LRR-RLKs) and proteins (LRR-RLPs), LRR containing defence response regulators, TFs from bZIP, ERF and WRKY families, xyloglucan cell wall transglycolases/hydrolases and exordium proteins were differentially expressed in both roots and leaves of plants treated with AcH 505. Only few genes, including specific RLKs and TFs, were induced in both AcH 505 and co-inoculation treatments.

Conclusion: Treatment with AcH 505 induces and maintains the expression levels of signalling genes encoding candidate receptor protein kinases and TFs and leads to differential expression of cell wall modification related genes in pedunculate oak microcuttings. Local gene expression response to AcH 505 alone and in combination with P. croceum are more pronounced when roots are in resting stages, possibly due to the fact that non growing roots re-direct their activity towards plant defence rather than growth.

No MeSH data available.


Related in: MedlinePlus