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The interaction of Arabidopsis with Piriformospora indica shifts from initial transient stress induced by fungus-released chemical mediators to a mutualistic interaction after physical contact of the two symbionts.

Vahabi K, Sherameti I, Bakshi M, Mrozinska A, Ludwig A, Reichelt M, Oelmüller R - BMC Plant Biol. (2015)

Bottom Line: Once a physical contact is established, the stomata re-open, ROS and phytohormone levels decline, and the number and expression level of defense/stress-related genes decreases.We propose that exudated compounds from P. indica induce stress and defense responses in the host.Root colonization results in the down-regulation of defense responses and the activation of genes involved in promoting plant growth, metabolism and performance.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Piriformospora indica, an endophytic fungus of Sebacinales, colonizes the roots of many plant species including Arabidopsis thaliana. The symbiotic interaction promotes plant performance, growth and resistance/tolerance against abiotic and biotic stress.

Results: We demonstrate that exudated compounds from the fungus activate stress and defense responses in the Arabidopsis roots and shoots before the two partners are in physical contact. They induce stomata closure, stimulate reactive oxygen species (ROS) production, stress-related phytohormone accumulation and activate defense and stress genes in the roots and/or shoots. Once a physical contact is established, the stomata re-open, ROS and phytohormone levels decline, and the number and expression level of defense/stress-related genes decreases.

Conclusions: We propose that exudated compounds from P. indica induce stress and defense responses in the host. Root colonization results in the down-regulation of defense responses and the activation of genes involved in promoting plant growth, metabolism and performance.

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Venn datagram of the number of genes which are up- or down-regulated in Arabidopsis roots exposed toP. indicafor either two or six days. Numbers of genes regulated only after 2 d of interaction are shown in red colour; those regulated only after 6 d are shown in blue; number of genes regulated at both time points are shown in green. The results are based on 3 independent biological experiments.
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Fig5: Venn datagram of the number of genes which are up- or down-regulated in Arabidopsis roots exposed toP. indicafor either two or six days. Numbers of genes regulated only after 2 d of interaction are shown in red colour; those regulated only after 6 d are shown in blue; number of genes regulated at both time points are shown in green. The results are based on 3 independent biological experiments.

Mentions: Roots exposed to P. indica for two and six days were harvested for RNA extraction and expression profiling. Root material exposed to agar plaques served as control. Only genes from P. indica-exposed material which showed a > 3-fold difference to the agar control were analysed in this study. The comparative transcriptome analysis [18] uncovered that 75 genes were up-regulated and 14 genes down-regulated after two days, whereas 50 genes were up-regulated and 4 genes down-regulated after six days (Figure 5; Figure 6; Additional file 1: Table S1A, C). Categorization of the genes using the Mapman software revealed a huge difference between the two datasets.Figure 5


The interaction of Arabidopsis with Piriformospora indica shifts from initial transient stress induced by fungus-released chemical mediators to a mutualistic interaction after physical contact of the two symbionts.

Vahabi K, Sherameti I, Bakshi M, Mrozinska A, Ludwig A, Reichelt M, Oelmüller R - BMC Plant Biol. (2015)

Venn datagram of the number of genes which are up- or down-regulated in Arabidopsis roots exposed toP. indicafor either two or six days. Numbers of genes regulated only after 2 d of interaction are shown in red colour; those regulated only after 6 d are shown in blue; number of genes regulated at both time points are shown in green. The results are based on 3 independent biological experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4384353&req=5

Fig5: Venn datagram of the number of genes which are up- or down-regulated in Arabidopsis roots exposed toP. indicafor either two or six days. Numbers of genes regulated only after 2 d of interaction are shown in red colour; those regulated only after 6 d are shown in blue; number of genes regulated at both time points are shown in green. The results are based on 3 independent biological experiments.
Mentions: Roots exposed to P. indica for two and six days were harvested for RNA extraction and expression profiling. Root material exposed to agar plaques served as control. Only genes from P. indica-exposed material which showed a > 3-fold difference to the agar control were analysed in this study. The comparative transcriptome analysis [18] uncovered that 75 genes were up-regulated and 14 genes down-regulated after two days, whereas 50 genes were up-regulated and 4 genes down-regulated after six days (Figure 5; Figure 6; Additional file 1: Table S1A, C). Categorization of the genes using the Mapman software revealed a huge difference between the two datasets.Figure 5

Bottom Line: Once a physical contact is established, the stomata re-open, ROS and phytohormone levels decline, and the number and expression level of defense/stress-related genes decreases.We propose that exudated compounds from P. indica induce stress and defense responses in the host.Root colonization results in the down-regulation of defense responses and the activation of genes involved in promoting plant growth, metabolism and performance.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Piriformospora indica, an endophytic fungus of Sebacinales, colonizes the roots of many plant species including Arabidopsis thaliana. The symbiotic interaction promotes plant performance, growth and resistance/tolerance against abiotic and biotic stress.

Results: We demonstrate that exudated compounds from the fungus activate stress and defense responses in the Arabidopsis roots and shoots before the two partners are in physical contact. They induce stomata closure, stimulate reactive oxygen species (ROS) production, stress-related phytohormone accumulation and activate defense and stress genes in the roots and/or shoots. Once a physical contact is established, the stomata re-open, ROS and phytohormone levels decline, and the number and expression level of defense/stress-related genes decreases.

Conclusions: We propose that exudated compounds from P. indica induce stress and defense responses in the host. Root colonization results in the down-regulation of defense responses and the activation of genes involved in promoting plant growth, metabolism and performance.

Show MeSH