Nejvíce citovaný článek - PubMed ID 24291089
Local auxin sources orient the apical-basal axis in Arabidopsis embryos
BACKGROUND: The increasing ambient temperature significantly impacts plant growth, development, and reproduction. Uncovering the temperature-regulating mechanisms in plants is of high importance, for increasing our fundamental understanding of plant thermomorphogenesis, for its potential in applied science, and for aiding plant breeders in improving plant thermoresilience. Thermomorphogenesis, the developmental response to warm temperatures, has been primarily studied in seedlings and in the regulation of flowering time. PHYTOCHROME B and PHYTOCHROME-INTERACTING FACTORs (PIFs), particularly PIF4, are key components of this response. However, the thermoresponse of other adult vegetative tissues and reproductive structures has not been systematically evaluated, especially concerning the involvement of phyB and PIFs. RESULTS: We screened the temperature responses of the wild type and several phyB-PIF4 pathway Arabidopsis mutant lines in combined and integrative phenotyping platforms for root growth in soil, shoot, inflorescence, and seed. Our findings demonstrate that phyB-PIF4 is generally involved in the relay of temperature signals throughout plant development, including the reproductive stage. Furthermore, we identified correlative responses to high ambient temperature between shoot and root tissues. This integrative and automated phenotyping was complemented by monitoring the changes in transcript levels in reproductive organs. Transcriptomic profiling of the pistils from plants grown under high ambient temperature identified key elements that may provide insight into the molecular mechanisms behind temperature-induced reduced fertilization rate. These include a downregulation of auxin metabolism, upregulation of genes involved auxin signalling, miRNA156 and miRNA160 pathways, and pollen tube attractants. CONCLUSIONS: Our findings demonstrate that phyB-PIF4 involvement in the interpretation of temperature signals is pervasive throughout plant development, including processes directly linked to reproduction.
- Klíčová slova
- Arabidopsis, Automatic phenotyping, PIF4, Pistils, Pollen tube guidance, Seeds, Thermomorphogenesis, phyB,
- MeSH
- Arabidopsis * genetika metabolismus růst a vývoj fyziologie MeSH
- fenotyp * MeSH
- fytochrom B * metabolismus genetika MeSH
- kořeny rostlin genetika metabolismus růst a vývoj MeSH
- květy genetika růst a vývoj MeSH
- proteiny huseníčku * genetika metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- signální transdukce MeSH
- transkripční faktory bHLH * genetika metabolismus MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- fytochrom B * MeSH
- PHYB protein, Arabidopsis MeSH Prohlížeč
- PIF4 protein, Arabidopsis MeSH Prohlížeč
- proteiny huseníčku * MeSH
- transkripční faktory bHLH * MeSH
For many years, research has been carried out with the aim of understanding the mechanism of auxin action, its biosynthesis, catabolism, perception, and transport. One central interest is the auxin-dependent gene expression regulation mechanism involving AUXIN RESPONSE FACTOR (ARF) transcription factors and their repressors, the AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) proteins. Numerous studies have been focused on MONOPTEROS (MP)/ARF5, an activator of auxin-dependent gene expression with a crucial impact on plant development. This review summarizes over 30 years of research on MP/ARF5. We indicate the available analytical tools to study MP/ARF5 and point out the known mechanism of MP/ARF5-dependent regulation of gene expression during various developmental processes, namely embryogenesis, leaf formation, vascularization, and shoot and root meristem formation. However, many questions remain about the auxin dose-dependent regulation of gene transcription by MP/ARF5 and its isoforms in plant cells, the composition of the MP/ARF5 protein complex, and, finally, all the genes under its direct control. In addition, information on post-translational modifications of MP/ARF5 protein is marginal, and knowledge about their consequences on MP/ARF5 function is limited. Moreover, the epigenetic factors and other regulators that act upstream of MP/ARF5 are poorly understood. Their identification will be a challenge in the coming years.
- Klíčová slova
- Arabidopsis thaliana, auxin, embryogenesis, flowering, meristem, plant, transcription factor, vascularization,
- MeSH
- Arabidopsis * metabolismus MeSH
- DNA vazebné proteiny genetika MeSH
- kyseliny indoloctové metabolismus MeSH
- proteiny huseníčku * genetika metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- transkripční faktory genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- DNA vazebné proteiny MeSH
- kyseliny indoloctové MeSH
- proteiny huseníčku * MeSH
- transkripční faktory MeSH
ClearSee alpha and FAST9 were optimized for imaging Arabidopsis seeds up to the torpedo stages. The methods preserve the fluorescence of reporter proteins and seed shape, allowing phenotyping embryos in intact seeds. Tissue clearing methods eliminate the need for sectioning, thereby helping better understand the 3D organization of tissues and organs. In the past fifteen years, clearing methods have been developed to preserve endogenous fluorescent protein tags. Some of these methods (ClearSee, TDE, PEA-Clarity, etc.) were adapted to clear various plant species, with the focus on roots, leaves, shoot apical meristems, and floral parts. However, these methods have not been used in developing seeds beyond the early globular stage. Tissue clearing is problematic in post-globular seeds due to various apoplastic barriers and secondary metabolites. In this study, we compared six methods for their efficiency in clearing Arabidopsis thaliana seeds at post-globular embryonic stages. Three methods (TDE, ClearSee, and ClearSee alpha) have already been reported in plants, whereas the others (fsDISCO, FAST9, and CHAPS clear) are used in this context for the first time. These methods were assessed for seed morphological changes, clearing capacity, removal of tannins, and spectral properties. We tested each method in seeds from globular to mature stages. The pros and cons of each method are listed herein. ClearSee alpha appears to be the method of choice as it preserves seed morphology and prevents tannin oxidation. However, FAST9 with 60% iohexol as a mounting medium is faster, clears better, and appears suitable for embryonic shape imaging. Our results may guide plant researchers to choose a suitable method for imaging fluorescent protein-labeled embryos in intact Arabidopsis seeds.
- Klíčová slova
- Arabidopsis seed clearing, ClearSee alpha, FAST9, Fluorescence preservation, Iohexol, Microscopy imaging,
- MeSH
- Arabidopsis * metabolismus MeSH
- rostliny MeSH
- semena rostlinná metabolismus MeSH
- xylitol metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- ClearSee MeSH Prohlížeč
- xylitol MeSH
The level of phytohormones such as abscisic acid (ABA) and auxins (Aux) changes dynamically during embryogenesis. Knowledge of the transcriptional activity of the genes of their metabolic pathways is essential for a deeper understanding of embryogenesis itself; however, it could also help breeding programs of important plants, such as Cannabis sativa, attractive for the pharmaceutical, textile, cosmetic, and food industries. This work aimed to find out how genes of metabolic pathways of Aux (IAA-1, IAA-2, X15-1, X15-2) and ABA (PP2C-1) alongside one member of the LEA gene family (CanLea34) are expressed in embryos depending on the developmental stage and the embryo cultivation in vitro. Walking stick (WS) and mature (M) cultivated and uncultivated embryos of C. sativa cultivars 'KC Dora' and 'USO 31' were analyzed. The RT-qPCR results indicated that for the development of immature (VH) embryos, the genes (IAA-1, IAA-2) are likely to be fundamental. Only an increased expression of the CanLea34 gene was characteristic of the fully maturated (M) embryos. In addition, this feature was significantly increased by cultivation. In conclusion, the cultivation led to the upsurge of expression of all studied genes.
- Klíčová slova
- Cannabis sativa, LEA gene, RT-qPCR, abscisic acid, auxin, embryo cultures, embryogenesis, gene expression,
- Publikační typ
- časopisecké články MeSH
The phytohormone auxin is a master regulator of plant growth and development in response to many endogenous and environmental signals. The underlying coordination of growth is mediated by the formation of auxin maxima and concentration gradients. The visualization of auxin dynamics and distribution can therefore provide essential information to increase our understanding of the mechanisms by which auxin orchestrates these growth and developmental processes. Several auxin reporters have been developed to better perceive the auxin distribution and signaling machinery in vivo. This review focuses on different types of auxin reporters and biosensors used to monitor auxin distribution and its dynamics, as well as auxin signaling, at the cellular and tissue levels in different plant species. We provide a brief history of each reporter and biosensor group and explain their principles and utilities.
Plant cell growth responds rapidly to various stimuli, adapting architecture to environmental changes. Two major endogenous signals regulating growth are the phytohormone auxin and the secreted peptides rapid alkalinization factors (RALFs). Both trigger very rapid cellular responses and also exert long-term effects [Du et al., Annu. Rev. Plant Biol. 71, 379-402 (2020); Blackburn et al., Plant Physiol. 182, 1657-1666 (2020)]. However, the way, in which these distinct signaling pathways converge to regulate growth, remains unknown. Here, using vertical confocal microscopy combined with a microfluidic chip, we addressed the mechanism of RALF action on growth. We observed correlation between RALF1-induced rapid Arabidopsis thaliana root growth inhibition and apoplast alkalinization during the initial phase of the response, and revealed that RALF1 reversibly inhibits primary root growth through apoplast alkalinization faster than within 1 min. This rapid apoplast alkalinization was the result of RALF1-induced net H+ influx and was mediated by the receptor FERONIA (FER). Furthermore, we investigated the cross-talk between RALF1 and the auxin signaling pathways during root growth regulation. The results showed that RALF-FER signaling triggered auxin signaling with a delay of approximately 1 h by up-regulating auxin biosynthesis, thus contributing to sustained RALF1-induced growth inhibition. This biphasic RALF1 action on growth allows plants to respond rapidly to environmental stimuli and also reprogram growth and development in the long term.
- Klíčová slova
- RALF1, auxin, biphasic regulation, cross-talk, root growth inhibition,
- MeSH
- Arabidopsis * metabolismus MeSH
- fosfotransferasy MeSH
- kořeny rostlin * růst a vývoj MeSH
- kyseliny indoloctové * metabolismus MeSH
- peptidové hormony * metabolismus MeSH
- proteiny huseníčku * metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- At3g51550 protein, Arabidopsis MeSH Prohlížeč
- fosfotransferasy MeSH
- kyseliny indoloctové * MeSH
- peptidové hormony * MeSH
- proteiny huseníčku * MeSH
- RALF1 protein, Arabidopsis MeSH Prohlížeč
Brassica napus (rapeseed) is the second most important oilseed crop worldwide. Global rise in average ambient temperature and extreme weather severely impact rapeseed seed yield. However, fewer research explained the phenotype changes caused by moderate-to-high temperatures in rapeseed. To investigate these events, we determined the long-term response of three spring cultivars to different temperature regimes (21/18°C, 28/18°C, and 34/18°C) mimicking natural temperature variations. The analysis focused on the plant appearance, seed yield, quality and viability, and embryo development. Our microscopic observations suggest that embryonic development is accelerated and defective in high temperatures. Reduced viable seed yield at warm ambient temperature is due to a reduced fertilization rate, increased abortion rate, defective embryonic development, and pre-harvest sprouting. Reduced auxin levels in young seeds and low ABA and auxin levels in mature seeds may cause embryo pattern defects and reduced seed dormancy, respectively. Glucosinolates and oil composition measurements suggest reduced seed quality. These identified cues help understand seed thermomorphogenesis and pave the way to developing thermoresilient rapeseed.
- Klíčová slova
- Brassica napus, embryo development, high temperatures, hormonal profiling, oil content, seed development, thermomorphogenesis,
- Publikační typ
- časopisecké články MeSH
Embryogenesis in seed plants is the process during which a single cell develops into a mature multicellular embryo that encloses all the modules and primary patterns necessary to build the architecture of the new plant after germination. This process involves a series of cell divisions and coordinated cell fate determinations resulting in the formation of an embryonic pattern with a shoot-root axis and cotyledon(s). The phytohormone auxin profoundly controls pattern formation during embryogenesis. Auxin functions in the embryo through its maxima/minima distribution, which acts as an instructive signal for tissue specification and organ initiation. In this review, we describe how disruptions of auxin biosynthesis, transport, and response severely affect embryo development. Also, the mechanism of auxin action in the development of the shoot-root axis and the three-tissue system is discussed with recent findings. Biological tools that can be implemented to study the auxin function during embryo development are presented, as they may be of interest to the reader.
- MeSH
- biologický transport MeSH
- kořeny rostlin růst a vývoj MeSH
- kyseliny indoloctové metabolismus MeSH
- regulátory růstu rostlin metabolismus MeSH
- semena rostlinná růst a vývoj MeSH
- signální transdukce MeSH
- výhonky rostlin růst a vývoj MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- kyseliny indoloctové MeSH
- regulátory růstu rostlin MeSH
Spontaneously arising channels that transport the phytohormone auxin provide positional cues for self-organizing aspects of plant development such as flexible vasculature regeneration or its patterning during leaf venation. The auxin canalization hypothesis proposes a feedback between auxin signaling and transport as the underlying mechanism, but molecular players await discovery. We identified part of the machinery that routes auxin transport. The auxin-regulated receptor CAMEL (Canalization-related Auxin-regulated Malectin-type RLK) together with CANAR (Canalization-related Receptor-like kinase) interact with and phosphorylate PIN auxin transporters. camel and canar mutants are impaired in PIN1 subcellular trafficking and auxin-mediated PIN polarization, which macroscopically manifests as defects in leaf venation and vasculature regeneration after wounding. The CAMEL-CANAR receptor complex is part of the auxin feedback that coordinates polarization of individual cells during auxin canalization.
- MeSH
- Arabidopsis enzymologie genetika MeSH
- biologický transport MeSH
- kyseliny indoloctové metabolismus MeSH
- mapování interakce mezi proteiny MeSH
- membránové transportní proteiny metabolismus MeSH
- proteinkinasy genetika metabolismus MeSH
- proteiny huseníčku metabolismus MeSH
- transkripční faktory metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- kyseliny indoloctové MeSH
- membránové transportní proteiny MeSH
- PIN1 protein, Arabidopsis MeSH Prohlížeč
- proteinkinasy MeSH
- proteiny huseníčku MeSH
- transkripční faktory MeSH
- WRKY23 protein, Arabidopsis MeSH Prohlížeč
Directional transport of the phytohormone auxin is a versatile, plant-specific mechanism regulating many aspects of plant development. The recently identified plant hormones, strigolactones (SLs), are implicated in many plant traits; among others, they modify the phenotypic output of PIN-FORMED (PIN) auxin transporters for fine-tuning of growth and developmental responses. Here, we show in pea and Arabidopsis that SLs target processes dependent on the canalization of auxin flow, which involves auxin feedback on PIN subcellular distribution. D14 receptor- and MAX2 F-box-mediated SL signaling inhibits the formation of auxin-conducting channels after wounding or from artificial auxin sources, during vasculature de novo formation and regeneration. At the cellular level, SLs interfere with auxin effects on PIN polar targeting, constitutive PIN trafficking as well as clathrin-mediated endocytosis. Our results identify a non-transcriptional mechanism of SL action, uncoupling auxin feedback on PIN polarity and trafficking, thereby regulating vascular tissue formation and regeneration.
- MeSH
- Arabidopsis genetika metabolismus MeSH
- heterocyklické sloučeniny tricyklické metabolismus MeSH
- hrách setý genetika metabolismus MeSH
- kyseliny indoloctové metabolismus MeSH
- laktony metabolismus MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulace genové exprese u rostlin genetika fyziologie MeSH
- regulátory růstu rostlin metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- GR24 strigolactone MeSH Prohlížeč
- heterocyklické sloučeniny tricyklické MeSH
- kyseliny indoloctové MeSH
- laktony MeSH
- proteiny huseníčku MeSH
- regulátory růstu rostlin MeSH
