Temperature passively affects biological processes involved in plant growth. Therefore, it is challenging to study the dedicated temperature signalling pathways that orchestrate thermomorphogenesis, a suite of elongation growth-based adaptations that enhance leaf-cooling capacity. We screened a chemical library for compounds that restored hypocotyl elongation in the pif4-2-deficient mutant background at warm temperature conditions in Arabidopsis thaliana to identify modulators of thermomorphogenesis. The small aromatic compound 'Heatin', containing 1-iminomethyl-2-naphthol as a pharmacophore, was selected as an enhancer of elongation growth. We show that ARABIDOPSIS ALDEHYDE OXIDASES redundantly contribute to Heatin-mediated hypocotyl elongation. Following a chemical proteomics approach, the members of the NITRILASE1-subfamily of auxin biosynthesis enzymes were identified among the molecular targets of Heatin. Our data reveal that nitrilases are involved in promotion of hypocotyl elongation in response to high temperature and Heatin-mediated hypocotyl elongation requires the NITRILASE1-subfamily members, NIT1 and NIT2. Heatin inhibits NIT1-subfamily enzymatic activity in vitro and the application of Heatin accordingly results in the accumulation of NIT1-subfamily substrate indole-3-acetonitrile in vivo. However, levels of the NIT1-subfamily product, bioactive auxin (indole-3-acetic acid), were also significantly increased. It is likely that the stimulation of hypocotyl elongation by Heatin might be independent of its observed interaction with NITRILASE1-subfamily members. However, nitrilases may contribute to the Heatin response by stimulating indole-3-acetic acid biosynthesis in an indirect way. Heatin and its functional analogues present novel chemical entities for studying auxin biology.
- Klíčová slova
- 1-iminomethyl-2-naphthol, Arabidopsis, Heatin, IAN, NIT1-subfamily, PIF4, aldehyde oxidase, chemical genetics, indole-3-acetonitrile, nitrilases, thermomorphogenesis,
- MeSH
- aldehydoxidasa genetika metabolismus MeSH
- aminohydrolasy genetika metabolismus MeSH
- apomorfin analogy a deriváty farmakologie MeSH
- Arabidopsis účinky léků růst a vývoj MeSH
- herbicidy farmakologie MeSH
- hypokotyl účinky léků růst a vývoj MeSH
- inhibitory enzymů aplikace a dávkování chemie farmakologie MeSH
- kyseliny indoloctové MeSH
- molekulární struktura MeSH
- pikloram farmakologie MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulace genové exprese u rostlin účinky léků MeSH
- transkriptom účinky léků MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- 10,11-dihydroxy-N-n-propylnorapomorphine MeSH Prohlížeč
- AAO1 protein, Arabidopsis MeSH Prohlížeč
- aldehydoxidasa MeSH
- aminohydrolasy MeSH
- apomorfin MeSH
- herbicidy MeSH
- inhibitory enzymů MeSH
- kyseliny indoloctové MeSH
- nitrilase MeSH Prohlížeč
- pikloram MeSH
- proteiny huseníčku MeSH
The plant-specific receptor-like cytoplasmic kinases (RLCKs) form a large, poorly characterized family. Members of the RLCK VI_A class of dicots have a unique characteristic: their activity is regulated by Rho-of-plants (ROP) GTPases. The biological function of one of these kinases was investigated using a T-DNA insertion mutant and RNA interference. Loss of RLCK VI_A2 function resulted in restricted cell expansion and seedling growth. Although these phenotypes could be rescued by exogenous gibberellin, the mutant did not exhibit lower levels of active gibberellins nor decreased gibberellin sensitivity. Transcriptome analysis confirmed that gibberellin is not the direct target of the kinase; its absence rather affected the metabolism and signalling of other hormones such as auxin. It is hypothesized that gibberellins and the RLCK VI_A2 kinase act in parallel to regulate cell expansion and plant growth. Gene expression studies also indicated that the kinase might have an overlapping role with the transcription factor circuit (PIF4-BZR1-ARF6) controlling skotomorphogenesis-related hypocotyl/cotyledon elongation. Furthermore, the transcriptomic changes revealed that the loss of RLCK VI_A2 function alters cellular processes that are associated with cell membranes, take place at the cell periphery or in the apoplast, and are related to cellular transport and/or cell wall reorganisation.
- Klíčová slova
- Arabidopsis thaliana, cell expansion, gibberellins, hypocotyl growth, plant hormones, plant size, receptor-like cytoplasmic kinase, skotomorphogenesis, transcriptomic analysis,
- MeSH
- Arabidopsis účinky léků enzymologie genetika růst a vývoj MeSH
- DNA bakterií genetika metabolismus MeSH
- DNA vazebné proteiny genetika metabolismus MeSH
- geneticky modifikované rostliny MeSH
- gibereliny metabolismus farmakologie MeSH
- hypokotyl účinky léků enzymologie genetika růst a vývoj MeSH
- inzerční mutageneze MeSH
- kotyledon účinky léků enzymologie genetika růst a vývoj MeSH
- kyseliny indoloctové metabolismus farmakologie MeSH
- protein-serin-threoninkinasy genetika metabolismus MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulace genové exprese u rostlin * MeSH
- regulátory růstu rostlin farmakologie MeSH
- semenáček účinky léků enzymologie genetika růst a vývoj MeSH
- stanovení celkové genové exprese MeSH
- transkripční faktory bHLH genetika metabolismus MeSH
- transkripční faktory genetika metabolismus MeSH
- transkriptom MeSH
- vývojová regulace genové exprese MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- auxin response factor 6, Arabidopsis MeSH Prohlížeč
- BZR1 protein, Arabidopsis MeSH Prohlížeč
- DNA bakterií MeSH
- DNA vazebné proteiny MeSH
- gibereliny MeSH
- kyseliny indoloctové MeSH
- PIF4 protein, Arabidopsis MeSH Prohlížeč
- protein-serin-threoninkinasy MeSH
- proteiny huseníčku MeSH
- regulátory růstu rostlin MeSH
- T-DNA MeSH Prohlížeč
- transkripční faktory bHLH MeSH
- transkripční faktory MeSH
Polar auxin transport plays a pivotal role in plant growth and development. PIN-FORMED (PIN) auxin efflux carriers regulate directional auxin movement by establishing local auxin maxima, minima, and gradients that drive multiple developmental processes and responses to environmental signals. Auxin has been proposed to modulate its own transport by regulating subcellular PIN trafficking via processes such as clathrin-mediated PIN endocytosis and constitutive recycling. Here, we further investigated the mechanisms by which auxin affects PIN trafficking by screening auxin analogs and identified pinstatic acid (PISA) as a positive modulator of polar auxin transport in Arabidopsis (Arabidopsis thaliana). PISA had an auxin-like effect on hypocotyl elongation and adventitious root formation via positive regulation of auxin transport. PISA did not activate SCFTIR1/AFB signaling and yet induced PIN accumulation at the cell surface by inhibiting PIN internalization from the plasma membrane. This work demonstrates PISA to be a promising chemical tool to dissect the regulatory mechanisms behind subcellular PIN trafficking and auxin transport.
- MeSH
- Arabidopsis účinky léků metabolismus MeSH
- biologický transport účinky léků MeSH
- buněčná membrána účinky léků metabolismus MeSH
- endocytóza * účinky léků MeSH
- fenotyp MeSH
- fenylacetáty farmakologie MeSH
- gravitropismus účinky léků MeSH
- hypokotyl účinky léků růst a vývoj MeSH
- kořeny rostlin účinky léků růst a vývoj MeSH
- kyseliny indoloctové metabolismus MeSH
- proteiny huseníčku metabolismus MeSH
- signální transdukce MeSH
- výhonky rostlin metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- fenylacetáty MeSH
- kyseliny indoloctové MeSH
- phenylacetic acid MeSH Prohlížeč
- pinstatic acid MeSH Prohlížeč
- proteiny huseníčku MeSH
Phytohormones are crucial molecules regulating plant development and responses to environmental challenges, including abiotic stresses, microbial and insect attacks. Most notably, phytohormones play important roles in the biosynthesis of lignocellulosics. Jasmonates are involved in secondary growth and secondary metabolism, such as phenylpropanoids and lignin biosyntheses. At the physiological and molecular levels, the actions of phytohormones depend on subtle concentration changes, as well as antagonistic equilibria between two or more of these molecules. In this article, we investigate the consequences of jasmonic acid (JA) spraying on young hemp hypocotyls. First, we show that JA application results in changes in the monomeric composition of lignin. Second, we highlight that, five days after application, JA leads to an increase in salicylic acid (SA) content in hemp hypocotyls. These results are discussed in the light of the known antagonism between JA and SA at both the physiological and molecular levels.
- Klíčová slova
- Hemp, jasmonic acid, lignin composition, salicylic acid,
- MeSH
- Cannabis účinky léků metabolismus MeSH
- cyklopentany farmakologie MeSH
- hypokotyl účinky léků růst a vývoj metabolismus MeSH
- kyselina salicylová farmakologie MeSH
- lignin metabolismus MeSH
- oxylipiny farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- cyklopentany MeSH
- jasmonic acid MeSH Prohlížeč
- kyselina salicylová MeSH
- lignin MeSH
- oxylipiny MeSH
Flax (Linum usitatissimum L.) is an important crop for the production of oil and fiber. In vitro manipulations of flax are used for genetic improvement and breeding while improvements in adventitious root formation are important for biotechnological programs focused on regeneration and vegetative propagation of genetically valuable plant material. Additionally, flax hypocotyl segments possess outstanding morphogenetic capacity, thus providing a useful model for the investigation of flax developmental processes. Here, we investigated the crosstalk between hydrogen peroxide and auxin with respect to reprogramming flax hypocotyl cells for root morphogenetic development. Exogenous auxin induced the robust formation of adventitious roots from flax hypocotyl segments while the addition of hydrogen peroxide further enhanced this process. The levels of endogenous auxin (indole-3-acetic acid; IAA) were positively correlated with increased root formation in response to exogenous auxin (1-Naphthaleneacetic acid; NAA). Histochemical staining of the hypocotyl segments revealed that hydrogen peroxide and peroxidase, but not superoxide, were positively correlated with root formation. Measurements of antioxidant enzyme activities showed that endogenous levels of hydrogen peroxide were controlled by peroxidases during root formation from hypocotyl segments. In conclusion, hydrogen peroxide positively affected flax adventitious root formation by regulating the endogenous auxin levels. Consequently, this agent can be applied to increase flax regeneration capacity for biotechnological purposes such as improved plant rooting.
- MeSH
- antioxidancia metabolismus MeSH
- biotechnologie MeSH
- hypokotyl účinky léků růst a vývoj metabolismus MeSH
- kořeny rostlin účinky léků růst a vývoj metabolismus MeSH
- kyseliny indoloctové metabolismus MeSH
- kyseliny naftalenoctové farmakologie MeSH
- len účinky léků růst a vývoj metabolismus MeSH
- peroxid vodíku metabolismus farmakologie MeSH
- přeprogramování buněk účinky léků MeSH
- regulátory růstu rostlin metabolismus farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- 1-naphthaleneacetic acid MeSH Prohlížeč
- antioxidancia MeSH
- indoleacetic acid MeSH Prohlížeč
- kyseliny indoloctové MeSH
- kyseliny naftalenoctové MeSH
- peroxid vodíku MeSH
- regulátory růstu rostlin MeSH
As sessile organisms, plants must sense environmental conditions and adjust their growth and development processes accordingly, through adaptive responses regulated by various internal factors, including hormones. A key environmental factor is temperature, but temperature-sensing mechanisms are not fully understood despite intense research. We investigated proteomic responses to temperature shocks (15 min cold or heat treatments) with and without exogenous applications of cytokinin in Arabidopsis. Image and mass spectrometric analysis of the two-dimensionally separated proteins detected 139 differentially regulated spots, in which 148 proteins were identified, most of which have not been previously linked to temperature perception. More than 70% of the temperature-shock response proteins were modulated by cytokinin, mostly in a similar manner as heat shock. Data mining of previous transcriptomic datasets supported extensive interactions between temperature and cytokinin signalling. The biological significance of this finding was tested by assaying an independent growth response of Arabidopsis seedlings to heat stress: hypocotyl elongation. This response was strongly inhibited in mutants with deficiencies in cytokinin signalling or endogenous cytokinin levels. Thus, cytokinins may directly participate in heat signalling in plants. Finally, large proportions of both temperature-shock and cytokinin responsive proteomes co-localize to the chloroplast, which might therefore host a substantial proportion of the temperature response machinery.
- Klíčová slova
- Arabidopsis thaliana, cold, heat, hormones, hypocotyl elongation, proteome, temperature,
- MeSH
- Arabidopsis genetika růst a vývoj MeSH
- biologické modely MeSH
- cytokininy farmakologie MeSH
- fosforylace účinky léků MeSH
- geneticky modifikované rostliny MeSH
- hypokotyl účinky léků genetika růst a vývoj MeSH
- metabolismus sacharidů účinky léků genetika MeSH
- mutace MeSH
- proteiny huseníčku klasifikace genetika metabolismus MeSH
- proteom metabolismus MeSH
- reakce na tepelný šok genetika MeSH
- rostlinné geny MeSH
- teplota * MeSH
- transkriptom účinky léků genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- cytokininy MeSH
- proteiny huseníčku MeSH
- proteom MeSH
