Dataset Information

The antibiotic peptaibol alamethicin from Trichoderma permeabilises Arabidopsis root apical meristem and epidermis but is antagonised by cellulase-induced resistance to alamethicin.

ABSTRACT:

Background

Trichoderma fungi live in the soil rhizosphere and are beneficial for plant growth and pathogen resistance. Several species and strains are currently used worldwide in co-cultivation with crops as a biocontrol alternative to chemical pesticides even though little is known about the exact mechanisms of the beneficial interaction. We earlier found alamethicin, a peptide antibiotic secreted by Trichoderma, to efficiently permeabilise cultured tobacco cells. However, pre-treatment with Trichoderma cellulase made the cells resistant to subsequent alamethicin, suggesting a potential mechanism for plant tolerance to Trichoderma, needed for mutualistic symbiosis.

Results

We here investigated intact sterile-grown Arabidopsis thaliana seedlings germinated in water or growth medium. These could be permeabilised by alamethicin but not if pretreated with cellulase. By following the fluorescence from the membrane-impermeable DNA-binding probe propidium iodide, we found alamethicin to mainly permeabilise root tips, especially the apical meristem and epidermis cells, but not the root cap and basal meristem cells nor cortex cells. Alamethicin permeabilisation and cellulase-induced resistance were confirmed by developing a quantitative in situ assay based on NADP-isocitrate dehydrogenase accessibility. The combined assays also showed that hyperosmotic treatment after the cellulase pretreatment abolished the induced cellulase resistance.

Conclusion

We here conclude the presence of cell-specific alamethicin permeabilisation, and cellulase-induced resistance to it, in root tip apical meristem and epidermis of the model organism A. thaliana. We suggest that contact between the plasma membrane and the cell wall is needed for the resistance to remain. Our results indicate a potential mode for the plant to avoid negative effects of alamethicin on plant growth and localises the point of potential damage and response. The results also open up for identification of plant genetic components essential for beneficial effects from Trichoderma on plants.

SUBMITTER: Dotson BR

PROVIDER: S-EPMC6086028 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The antibiotic peptaibol alamethicin from Trichoderma permeabilises Arabidopsis root apical meristem and epidermis but is antagonised by cellulase-induced resistance to alamethicin.

Dotson Bradley R BR Soltan Dia D Schmidt John J Areskoug Mariam M Rabe Kenny K Swart Corné C Widell Susanne S Rasmusson Allan G AG

BMC plant biology 20180810 1

<h4>Background</h4>Trichoderma fungi live in the soil rhizosphere and are beneficial for plant growth and pathogen resistance. Several species and strains are currently used worldwide in co-cultivation with crops as a biocontrol alternative to chemical pesticides even though little is known about the exact mechanisms of the beneficial interaction. We earlier found alamethicin, a peptide antibiotic secreted by Trichoderma, to efficiently permeabilise cultured tobacco cells. However, pre-treatment ...[more]

PMID: 30097019

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Project description:The study of the concerted action of hormones and transcription factors is fundamental to understand cell differentiation and pattern formation during organ development. The root apical meristem of Arabidopsis thaliana is a useful model to address this. It has a stem cell niche near its tip conformed of a quiescent organizer and stem or initial cells around it, then a proliferation domain followed by a transition domain, where cells diminish division rate before transiting to the elongation zone; here, cells grow anisotropically prior to their final differentiation towards the plant base. A minimal model of the gene regulatory network that underlies cell-fate specification and patterning at the root stem cell niche was proposed before. In this study, we update and couple such network with both the auxin and cytokinin hormone signaling pathways to address how they collectively give rise to attractors that correspond to the genetic and hormonal activity profiles that are characteristic of different cell types along A. thaliana root apical meristem. We used a Boolean model of the genetic-hormonal regulatory network to integrate known and predicted regulatory interactions into alternative models. Our analyses show that, after adding some putative missing interactions, the model includes the necessary and sufficient components and regulatory interactions to recover attractors characteristic of the root cell types, including the auxin and cytokinin activity profiles that correlate with different cellular behaviors along the root apical meristem. Furthermore, the model predicts the existence of activity configurations that could correspond to the transition domain. The model also provides a possible explanation for apparently paradoxical cellular behaviors in the root meristem. For example, how auxin may induce and at the same time inhibit WOX5 expression. According to the model proposed here the hormonal regulation of WOX5 might depend on the cell type. Our results illustrate how non-linear multi-stable qualitative network models can aid at understanding how transcriptional regulators and hormonal signaling pathways are dynamically coupled and may underlie both the acquisition of cell fate and the emergence of hormonal activity profiles that arise during complex organ development.

Dataset Information

The antibiotic peptaibol alamethicin from Trichoderma permeabilises Arabidopsis root apical meristem and epidermis but is antagonised by cellulase-induced resistance to alamethicin.

Background

Results

Conclusion

Publications

The antibiotic peptaibol alamethicin from Trichoderma permeabilises Arabidopsis root apical meristem and epidermis but is antagonised by cellulase-induced resistance to alamethicin.

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