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

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.

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Catechol, a major component of smoke, influences primary root growth and root hair elongation through reactive oxygen species‐mediated redox signaling

New Phytologist ◽

10.1111/nph.14317 ◽

2016 ◽

Vol 213 (4) ◽

pp. 1755-1770 ◽

Cited By ~ 8

Author(s):

Ming Wang ◽

Matthias Schoettner ◽

Shuqing Xu ◽

Christian Paetz ◽

Julia Wilde ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Root Growth ◽

Root Hair ◽

Primary Root ◽

Reactive Oxygen ◽

Redox Signaling ◽

Oxygen Species ◽

Primary Root Growth

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Nitrate inhibits primary root growth by reducing accumulation of reactive oxygen species in the root tip in Medicago truncatula

Plant Physiology and Biochemistry ◽

10.1016/j.plaphy.2019.11.006 ◽

2020 ◽

Vol 146 ◽

pp. 363-373 ◽

Cited By ~ 2

Author(s):

Lili Zang ◽

Marie-Christine Morère-Le Paven ◽

Thibault Clochard ◽

Alexis Porcher ◽

Pascale Satour ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Root Growth ◽

Medicago Truncatula ◽

Primary Root ◽

Reactive Oxygen ◽

Root Tip ◽

Oxygen Species ◽

Primary Root Growth

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Involvement of reactive oxygen species in lanthanum-induced inhibition of primary root growth

Journal of Experimental Botany ◽

10.1093/jxb/erw379 ◽

2016 ◽

Vol 67 (21) ◽

pp. 6149-6159 ◽

Cited By ~ 11

Author(s):

Yang-Yang Liu ◽

Ru-Ling Wang ◽

Ping Zhang ◽

Liang-liang Sun ◽

Jin Xu

Keyword(s):

Reactive Oxygen Species ◽

Root Growth ◽

Primary Root ◽

Reactive Oxygen ◽

Oxygen Species ◽

Primary Root Growth

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

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-01-15-0005-r ◽

2015 ◽

Vol 28 (6) ◽

pp. 701-710 ◽

Cited By ~ 52

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.

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

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-20-2-0207 ◽

2007 ◽

Vol 20 (2) ◽

pp. 207-217 ◽

Cited By ~ 146

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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Iron- and Ferritin-Dependent Reactive Oxygen Species Distribution: Impact on Arabidopsis Root System Architecture

Molecular Plant ◽

10.1016/j.molp.2014.11.014 ◽

2015 ◽

Vol 8 (3) ◽

pp. 439-453 ◽

Cited By ~ 42

Author(s):

Guilhem Reyt ◽

Soukaina Boudouf ◽

Jossia Boucherez ◽

Frédéric Gaymard ◽

Jean-Francois Briat

Keyword(s):

Reactive Oxygen Species ◽

Root System ◽

Species Distribution ◽

System Architecture ◽

Reactive Oxygen ◽

Root System Architecture ◽

Oxygen Species ◽

Arabidopsis Root

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

10.1101/2020.03.11.985820 ◽

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.

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JAR1 negatively regulates root growth under boron deficiency in Arabidopsis

Journal of Experimental Botany ◽

10.1093/jxb/erab041 ◽

2021 ◽

Author(s):

Yupu Huang ◽

Sheliang Wang ◽

Lei Shi ◽

Fangsen Xu

Keyword(s):

Plant Growth ◽

Root Growth ◽

Growth Inhibition ◽

Primary Root ◽

Root Growth Inhibition ◽

Boron Deficiency ◽

Ethylene Signaling ◽

Protein Levels ◽

Primary Root Growth ◽

Ja Signaling

Abstract Boron (B) is an essential micronutrient for plant growth and development. Jasmonic acid (JA) plays pivotal roles in plant growth. However, the underlying molecular mechanism of JA involvement in B-deficiency-induced root growth inhibition is yet to be explored. In this study, we investigated the response of JA to B deficiency and the mechanism of JAR1-dependent JA signaling in root growth inhibition under B deficiency. B deficiency enhanced JA signaling in roots, and root growth inhibition was partially restored by JA biosynthesis inhibition. jar1-1 (jasmonate-resistant 1, JAR1) mutant, mutants of coronatine-insensitive 1 (coi1-2) and myc2 defective in JA signaling showed insensitivity to B deficiency. Ethylene-overproduction mutant eto1 and ethylene-insensitive mutant etr1 showed sensitivity and insensitivity to B deficiency, respectively, suggesting that ethylene is involved in the inhibition of primary root growth under B deficiency. Furthermore, after a declined in EIN3 protein levels, which may contribute to root growth, ethylene signaling was weakened in the jar1-1 mutant root under B deficiency. Under B deficiency, B concentrations were increased in the roots and shoots of the jar1-1 mutant, owing to the large root system and its activity. Therefore, our findings revealed that JA, which is involved in the inhibition of root growth under B deficiency, is regulated by JAR1 activated JA and ethylene signaling pathways.

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Comprehensive Genome-Wide Association Analysis Reveals the Genetic Basis of Root System Architecture in Soybean

Frontiers in Plant Science ◽

10.3389/fpls.2020.590740 ◽

2020 ◽

Vol 11 ◽

Author(s):

Waldiodio Seck ◽

Davoud Torkamaneh ◽

François Belzile

Keyword(s):

Root System ◽

System Architecture ◽

Phenotypic Variation ◽

Genetic Basis ◽

Genome Wide Association Study ◽

Primary Root ◽

Root System Architecture ◽

Genome Wide Association ◽

Nucleotide Polymorphisms ◽

Genome Wide

Increasing the understanding genetic basis of the variability in root system architecture (RSA) is essential to improve resource-use efficiency in agriculture systems and to develop climate-resilient crop cultivars. Roots being underground, their direct observation and detailed characterization are challenging. Here, were characterized twelve RSA-related traits in a panel of 137 early maturing soybean lines (Canadian soybean core collection) using rhizoboxes and two-dimensional imaging. Significant phenotypic variation (P < 0.001) was observed among these lines for different RSA-related traits. This panel was genotyped with 2.18 million genome-wide single-nucleotide polymorphisms (SNPs) using a combination of genotyping-by-sequencing and whole-genome sequencing. A total of 10 quantitative trait locus (QTL) regions were detected for root total length and primary root diameter through a comprehensive genome-wide association study. These QTL regions explained from 15 to 25% of the phenotypic variation and contained two putative candidate genes with homology to genes previously reported to play a role in RSA in other species. These genes can serve to accelerate future efforts aimed to dissect genetic architecture of RSA and breed more resilient varieties.

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