scholarly journals Mitogen-Activated Protein Kinase 6 and Ethylene and Auxin Signaling Pathways Are Involved in Arabidopsis Root-System Architecture Alterations by Trichoderma atroviride

2015 ◽  
Vol 28 (6) ◽  
pp. 701-710 ◽  
Author(s):  
Hexon Angel Contreras-Cornejo ◽  
Jesús Salvador López-Bucio ◽  
Alejandro Méndez-Bravo ◽  
Lourdes Macías-Rodríguez ◽  
Maricela Ramos-Vega ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Root Growth ◽  
System Architecture ◽  
Primary Root ◽  
Root System Architecture ◽  
Mitogen Activated Protein Kinase ◽  
Auxin Signaling ◽  
Trichoderma Atroviride ◽  
Mitogen Activated Protein ◽  
Primary Root Growth

Trichoderma atroviride is a symbiotic fungus that interacts with roots and stimulates plant growth and defense. Here, we show that Arabidopsis seedlings cocultivated with T. atroviride have an altered root architecture and greater biomass compared with axenically grown seedlings. These effects correlate with increased activity of mitogen-activated protein kinase 6 (MPK6). The primary roots of mpk6 mutants showed an enhanced growth inhibition by T. atroviride when compared with wild-type (WT) plants, while T. atroviride increases MPK6 activity in WT roots. It was also found that T. atroviride produces ethylene (ET), which increases with l-methionine supply to the fungal growth medium. Analysis of growth and development of WT seedlings and etr1, ein2, and ein3 ET-related Arabidopsis mutants indicates a role for ET in root responses to the fungus, since etr1 and ein2 mutants show defective root-hair induction and enhanced primary-root growth inhibition when cocultivated with T. atroviride. Increased MPK6 activity was evidenced in roots of ctr1 mutants, which correlated with repression of primary root growth, thus connecting MPK6 signaling with an ET response pathway. Auxin-inducible gene expression analysis using the DR5:uidA reporter construct further revealed that ET affects auxin signaling through the central regulator CTR1 and that fungal-derived compounds, such as indole-3-acetic acid and indole-3-acetaldehyde, induce MPK6 activity. Our results suggest that T. atroviride likely alters root-system architecture modulating MPK6 activity and ET and auxin action.

scholarly journals Pyocyanin, a Virulence Factor Produced by Pseudomonas aeruginosa, Alters Root Development Through Reactive Oxygen Species and Ethylene Signaling in Arabidopsis

2014 ◽  
Vol 27 (4) ◽  
pp. 364-378 ◽  
Author(s):  
Randy Ortiz-Castro ◽  
Ramón Pelagio-Flores ◽  
Alfonso Méndez-Bravo ◽  
León Francisco Ruiz-Herrera ◽  
Jesús Campos-García ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Pseudomonas Aeruginosa ◽  
Root Growth ◽  
Virulence Factor ◽  
System Architecture ◽  
Primary Root ◽  
Root System Architecture ◽  
Oxygen Species ◽  
Ethylene Signaling ◽  
Primary Root Growth

Pyocyanin acts as a virulence factor in Pseudomonas aeruginosa, a plant and animal pathogen. In this study, we evaluated the effect of pyocyanin on growth and development of Arabidopsis seedlings. Root inoculation with P. aeruginosa PAO1 strain inhibited primary root growth in wild-type (WT) Arabidopsis seedlings. In contrast, single lasI– and double rhlI–/lasI– mutants of P. aeruginosa defective in pyocyanin production showed decreased root growth inhibition concomitant with an increased phytostimulation. Treatment with pyocyanin modulates root system architecture, inhibiting primary root growth and promoting lateral root and root hair formation without affecting meristem viability or causing cell death. These effects correlated with altered proportions of hydrogen peroxide and superoxide in root tips and with an inhibition of cell division and elongation. Mutant analyses showed that pyocyanin modulation of root growth was likely independent of auxin, cytokinin, and abscisic acid but required ethylene signaling because the Arabidopsis etr1-1, ein2-1, and ein3-1 ethylene-related mutants were less sensitive to pyocyanin-induced root stoppage and reactive oxygen species (ROS) distribution. Our findings suggest that pyocyanin is an important factor modulating the interplay between ROS production and root system architecture by an ethylene-dependent signaling.

Mitogen-activated protein kinase 6 integrates phosphate and iron responses for indeterminate root growth in Arabidopsis thaliana

Planta ◽  
2019 ◽  
Vol 250 (4) ◽  
pp. 1177-1189 ◽  
Author(s):  
Jesús Salvador López-Bucio ◽  
Guadalupe Jessica Salmerón-Barrera ◽  
Gustavo Ravelo-Ortega ◽  
Javier Raya-González ◽  
Patricia León ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Protein Kinase ◽  
Root Growth ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein

scholarly journals Disruption of CYCLOPHILIN 38 function reveals a photosynthesis-dependent systemic signal controlling lateral root emergence

2020 ◽  
Author(s):  
Lina Duan ◽  
Juan Manuel Pérez-Ruiz ◽  
Francisco Javier Cejudo ◽  
José R. Dinneny
Keyword(s):  
Root Growth ◽  
Root System ◽  
Lateral Root ◽  
System Development ◽  
Lateral Roots ◽  
Primary Root ◽  
Root System Architecture ◽  
Minor Effect ◽  
Low Light ◽  
Primary Root Growth

AbstractPhotosynthesis in leaves generates the fixed-carbon resources and essential metabolites that support sink tissues, such as roots [1]. One of these products, sucrose, is known to promote primary root growth, but it is not clear what other molecules may be involved and whether other stages of root system development are affected by photosynthate levels [2]. Through a mutant screen to identify pathways regulating root system architecture, we identified a mutation in the CYCLOPHILIN 38 (CYP38) gene, which causes an accumulation of pre-emergent stage lateral roots, with a minor effect on primary root growth. CYP38 was previously reported to maintain the stability of Photosystem II (PSII) in chloroplasts [3]. CYP38 expression is enriched in the shoot and grafting experiments show that the gene acts non-cell autonomously to promote lateral root emergence. Growth of wild-type plants under low light conditions phenocopied the cyp38 lateral root emergence phenotype as did the inhibition of PSII-dependent electron transport or NADPH production. Importantly, the cyp38 root phenotype is not rescued by exogenous sucrose, suggesting the involvement of another metabolite. Auxin (IAA) is an essential hormone promoting root growth and its biosynthesis from tryptophan is dependent on reductant generated during photosynthesis [4,5]. Both WT seedlings grown under low light and cyp38 mutants have highly diminished levels of IAA in root tissues. The cyp38 lateral root defect is rescued by IAA treatment, revealing that photosynthesis promotes lateral root emergence partly through IAA biosynthesis. Metabolomic profiling shows that the accumulation of several defense-related metabolites are also photosynthesis-dependent, suggesting that the regulation of a number of energy-intensive pathways are down-regulated when light becomes limiting.

scholarly journals Arabidopsis mitogen-activated protein kinase MPK12 interacts with the MAPK phosphatase IBR5 and regulates auxin signaling

2009 ◽  
Vol 57 (6) ◽  
pp. 975-985 ◽  
Author(s):  
Jin Suk Lee ◽  
Shucai Wang ◽  
Somrudee Sritubtim ◽  
Jin-Gui Chen ◽  
Brian E. Ellis
Keyword(s):  
Protein Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Auxin Signaling ◽  
Mitogen Activated Protein ◽  
Mapk Phosphatase

scholarly journals Trichoderma atroviridefrom Predator to Prey: Role of the Mitogen-Activated Protein Kinase Tmk3 in Fungal Chemical Defense against Fungivory byDrosophila melanogasterLarvae

2018 ◽  
Vol 85 (2) ◽  
Author(s):  
Karina Atriztán-Hernández ◽  
Abigail Moreno-Pedraza ◽  
Robert Winkler ◽  
Therese Markow ◽  
Alfredo Herrera-Estrella
Keyword(s):  
Protein Kinase ◽  
Secondary Metabolite ◽  
Asexual Reproduction ◽  
Defense Mechanism ◽  
Mitogen Activated Protein Kinase ◽  
Trichoderma Atroviride ◽  
Content Type ◽  
Metabolite Production ◽  
Mitogen Activated Protein

ABSTRACTThe response to injury represents an important strategy for animals and plants to survive mechanical damage and predation. Plants respond to injury by activating a defense response that includes the production of an important variety of compounds that help them withstand predator attack and recover from mechanical injury (MI). Similarly, the filamentous fungusTrichoderma atrovirideresponds to MI by strongly modifying its transcriptional profile and producing asexual reproduction structures (conidia). Here, we analyzed whether the response to MI inT. atrovirideis related to a possible predator defense mechanism from a metabolic perspective. We found that the production of specific groups of secondary metabolites increases in response to MI but is reduced after fungivory byDrosophila melanogasterlarvae. We further show that fungivory results in repression of the expression of genes putatively involved in the regulation of secondary metabolite production inT. atroviride. Activation of secondary metabolite production appears to depend on the mitogen-activated protein kinase (MAPK) Tmk3. Interestingly,D. melanogasterlarvae preferred to feed on atmk3gene replacement mutant rather than on the wild-type strain. Consumption of the mutant strain, however, resulted in increased larval mortality.IMPORTANCEFungi, like other organisms, have natural predators, including fungivorous nematodes and arthropods that use them as an important food source. Thus, they require mechanisms to detect and respond to injury.Trichoderma atrovirideresponds to mycelial injury by rapidly regenerating its hyphae and developing asexual reproduction structures. Whether this injury response is associated with attack by fungivorous insects is unknown. Therefore, determining the possible conservation of a defense mechanism to predation inT. atrovirideand plants and elucidating the mechanisms involved in the establishment of this response is of major interest. Here, we describe the chemical response ofT. atrovirideto mechanical injury and fungivory and the role of a MAPK pathway in the regulation of this response.

scholarly journals Bacillus megaterium Rhizobacteria Promote Growth and Alter Root-System Architecture Through an Auxin- and Ethylene-Independent Signaling Mechanism in Arabidopsis thaliana

2007 ◽  
Vol 20 (2) ◽  
pp. 207-217 ◽  
Author(s):  
José López-Bucio ◽  
Juan Carlos Campos-Cuevas ◽  
Erasto Hernández-Calderón ◽  
Crisanto Velásquez-Becerra ◽  
Rodolfo Farías-Rodríguez ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Growth ◽  
Root Hair ◽  
Lateral Root ◽  
Root Formation ◽  
Growth Promotion ◽  
Primary Root ◽  
Root System Architecture ◽  
Ethylene Signaling ◽  
Primary Root Growth

Soil microorganisms are critical players in plant-soil interactions at the rhizosphere. We have identified a Bacillus megaterium strain that promoted growth and development of bean (Phaseolus vulgaris) and Arabidopsis thaliana plants. We used Arabidopsis thaliana as a model to characterize the effects of inoculation with B. megaterium on plant-growth promotion and postembryonic root development. B. megaterium inoculation caused an inhibition in primary-root growth followed by an increase in lateral-root number, lateral-root growth, and root-hair length. Detailed cellular analyses revealed that primary root-growth inhibition was caused both by a reduction in cell elongation and by reduction of cell proliferation in the root meristem. To study the contribution of auxin and ethylene signaling pathways in the alterations in root-system architecture elicited by B. megaterium, a suite of plant hormone mutants of Arabidopsis, including aux1-7, axr4-1, eir1, etr1, ein2, and rhd6, defective in either auxin or ethylene signaling, were evaluated for their responses to inoculation with this bacteria. When inoculated, all mutant lines tested showed increased biomass production. Moreover, aux1-7 and eir1, which sustain limited root-hair and lateral-root formation when grown in uninoculated medium, were found to increase the number of lateral roots and to develop long root hairs when inoculated with B. megaterium. The ethylene-signaling mutants etr1 and ein2 showed an induction in lateral-root formation and root-hair growth in response to bacterial inoculation. Taken together, our results suggest that plant-growth promotion and root-architectural alterations by B. megaterium may involve auxin- and-ethylene independent mechanisms.

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