A Complex Molecular Interplay of Auxin and Ethylene Signaling Pathways Is Involved in Arabidopsis Growth Promotion by Burkholderia phytofirmans PsJN

Although not fully understood, molecular communication in the rhizosphere plays an important role regulating traits involved in plant–bacteria association. Burkholderia phytofirmans PsJN is a well-known plant-growth-promoting bacterium, which establishes rhizospheric and endophytic colonization in different plants. A competent colonization is essential for plant-growth-promoting effects produced by bacteria. Using appropriate mutant strains of B. phytofirmans, we obtained evidence for the importance of N-acyl homoserine lactone-mediated (quorum sensing) cell-to-cell communication in efficient colonization of Arabidopsis thaliana plants and the establishment of a beneficial interaction. We also observed that bacterial degradation of the auxin indole-3-acetic acid (IAA) plays a key role in plant-growth-promoting traits and is necessary for efficient rhizosphere colonization. Wildtype B. phytofirmans but not the iacC mutant in IAA mineralization is able to restore promotion effects in roots of A. thaliana in the presence of exogenously added IAA, indicating the importance of this trait for promoting primary root length. Using a transgenic A. thaliana line with suppressed auxin signaling (miR393) and analyzing the expression of auxin receptors in wild-type inoculated plants, we provide evidence that auxin signaling in plants is necessary for the growth promotion effects produced by B. phytofirmans. The interplay between ethylene and auxin signaling was also confirmed by the response of the plant to a 1-aminocyclopropane-1-carboxylate deaminase bacterial mutant strain.

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CONSTANS-Like 9 (OsCOL9) Interacts with Receptor for Activated C-Kinase 1(OsRACK1) to Regulate Blast Resistance through Salicylic Acid and Ethylene Signaling Pathways

PLoS ONE ◽

10.1371/journal.pone.0166249 ◽

2016 ◽

Vol 11 (11) ◽

pp. e0166249 ◽

Cited By ~ 9

Author(s):

Hao Liu ◽

Shuangyu Dong ◽

Dayuan Sun ◽

Wei Liu ◽

Fengwei Gu ◽

...

Keyword(s):

Salicylic Acid ◽

Signaling Pathways ◽

Blast Resistance ◽

Ethylene Signaling

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Jasmonic Acid and Ethylene Signaling Pathways Regulate Glucosinolate Levels in Plants During Rhizobacteria-Induced Systemic Resistance Against a Leaf-Chewing Herbivore

Journal of Chemical Ecology ◽

10.1007/s10886-016-0787-7 ◽

2016 ◽

Vol 42 (12) ◽

pp. 1212-1225 ◽

Cited By ~ 45

Author(s):

Nurmi Pangesti ◽

Michael Reichelt ◽

Judith E. van de Mortel ◽

Eleni Kapsomenou ◽

Jonathan Gershenzon ◽

...

Keyword(s):

Jasmonic Acid ◽

Signaling Pathways ◽

Induced Systemic Resistance ◽

Systemic Resistance ◽

Ethylene Signaling

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A network of phosphate starvation and immune-related signaling and metabolic pathways controls the interaction between Arabidopsis thaliana and the beneficial fungus Colletotrichum tofieldiae.

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-08-20-0233-r ◽

2020 ◽

Author(s):

Henning Frerigmann ◽

Markus Piotrowski ◽

René Lemke ◽

Paweł Bednarek ◽

Paul Schulze-Lefert

Keyword(s):

Arabidopsis Thaliana ◽

Growth Promotion ◽

Auxin Biosynthesis ◽

Auxin Signaling ◽

Ethylene Signaling ◽

In Planta ◽

Triple Mutant ◽

Hydrolysis Products ◽

Pi Starvation ◽

Pi Deficiency

The beneficial root-colonizing fungus Colletotrichum tofieldiae (Ct) mediates plant growth promotion (PGP) upon phosphate (Pi) starvation in Arabidopsis thaliana (Arabidopsis). This activity is dependent on the Trp-metabolism of the host, including indole glucosinolate (IG) hydrolysis. Here we show that Ct resolves several Pi starvation-induced molecular processes in the host, one of which is the downregulation of auxin signaling in germ-free plants, which is restored in the presence of the fungus. Using CRISPR/Cas9 genome editing, we generated an Arabidopsis triple mutant lacking three homologous nitrilases (NIT1-3) that are thought to link IG-hydrolysis products with auxin biosynthesis. Retained Ct-induced PGP in nit1;2;3 mutant plants demonstrated that this metabolic connection is dispensable for the beneficial activity of the fungus. This suggests that either there is an alternative metabolic link between IG-hydrolysis products and auxin biosynthesis, or that Ct restores auxin signaling independently of IG metabolism. We show that Ct, similar to pathogenic microorganisms, triggers Arabidopsis immune pathways that rely on IG metabolism as well as salicylic acid and ethylene signaling. Analysis of IG-deficient myb mutants revealed that these metabolites are indeed important for control of in planta Ct growth: however, enhanced Ct biomass does not necessarily negatively correlate with PGP. We show that Pi deficiency enables more efficient colonization of Arabidopsis by Ct, possibly due to the MYC2-mediated repression of ethylene signaling and changes in the constitutive IG composition in roots.

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Canonical and noncanonical ethylene signaling pathways that regulate Arabidopsis susceptibility to the cyst nematode Heterodera schachtii

New Phytologist ◽

10.1111/nph.15400 ◽

2018 ◽

Vol 221 (2) ◽

pp. 946-959 ◽

Cited By ~ 5

Author(s):

Sarbottam Piya ◽

Brad M. Binder ◽

Tarek Hewezi

Keyword(s):

Signaling Pathways ◽

Cyst Nematode ◽

Heterodera Schachtii ◽

Ethylene Signaling

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Signatures of signaling pathways underlying plant-growth promotion by fungi

Biocontrol Agents and Secondary Metabolites ◽

10.1016/b978-0-12-822919-4.00013-2 ◽

2021 ◽

pp. 321-346

Author(s):

Swapan Kumar Ghosh ◽

Atanu Panja

Keyword(s):

Plant Growth ◽

Signaling Pathways ◽

Plant Growth Promotion ◽

Growth Promotion

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Arabidopsis HB52 mediates the crosstalk between ethylene and auxin signaling pathways by regulating PIN2, WAG1, and WAG2 during primary root elongation

10.1101/246017 ◽

2018 ◽

Author(s):

Zi-Qing Miao ◽

Ping-Xia Zhao ◽

Jie-Li Mao ◽

Lin-Hui Yu ◽

Yang Yuan ◽

...

Keyword(s):

Root Growth ◽

Signaling Pathways ◽

Molecular Mechanism ◽

Root Elongation ◽

Auxin Transport ◽

Primary Root ◽

Auxin Signaling ◽

Elongation Zone ◽

Ethylene Signaling ◽

Physiological Processes

AbstractThe gaseous hormone ethylene participates in many physiological processes of plants. It is well known that ethylene-inhibited root elongation involves basipetal auxin delivery requiring PIN2. However, the molecular mechanism how ethylene regulates PIN2 is not well understood. Here, we report that the ethylene-responsive HD-Zip gene HB52 is involved in ethylene-mediated inhibition of primary root elongation. Using biochemical and genetic analyses, we demonstrated that HB52 is ethylene-responsive and acts immediately downstream of EIN3. HB52 knock-down mutants are insensitive to ethylene in primary root elongation while the overexpression lines have dramatically shortened roots like ethylene treated plants. Moreover, HB52 upregulates PIN2, WAG1, and WAG2 by directly binding to their promoter, leading to an enhanced basipetal auxin delivery to the elongation zone and thus inhibiting root growth. Our work uncovers HB52 as an important crosstalk node between ethylene signaling and auxin transport in root elongation.

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