Nejvíce citovaný článek - PubMed ID 25617434
Plant embryogenesis requires AUX/LAX-mediated auxin influx
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
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.
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
Eukaryotic cells rely on the accuracy and efficiency of vesicular traffic. In plants, disturbances in vesicular trafficking are well studied in quickly dividing root meristem cells or polar growing root hairs and pollen tubes. The development of the female gametophyte, a unique haploid reproductive structure located in the ovule, has received far less attention in studies of vesicular transport. Key molecules providing the specificity of vesicle formation and its subsequent recognition and fusion with the acceptor membrane are Rab proteins. Rabs are anchored to membranes by covalently linked geranylgeranyl group(s) that are added by the Rab geranylgeranyl transferase (RGT) enzyme. Here we show that Arabidopsis plants carrying mutations in the gene encoding the β-subunit of RGT (rgtb1) exhibit severely disrupted female gametogenesis and this effect is of sporophytic origin. Mutations in rgtb1 lead to internalization of the PIN1 and PIN3 proteins from the basal membranes to vesicles in provascular cells of the funiculus. Decreased transport of auxin out of the ovule is accompanied by auxin accumulation in tissue surrounding the growing gametophyte. In addition, female gametophyte development arrests at the uni- or binuclear stage in a significant portion of the rgtb1 ovules. These observations suggest that communication between the sporophyte and the developing female gametophyte relies on Rab-dependent vesicular traffic of the PIN1 and PIN3 transporters and auxin efflux out of the ovule.
- Klíčová slova
- Arabidopsis, PIN1, PIN3, Rab, auxin transport, female gametophyte, funiculus, ovule, rab geranylgeranyl transferase,
- MeSH
- Arabidopsis * genetika MeSH
- kyseliny indoloctové MeSH
- proteiny huseníčku * genetika MeSH
- pylová láčka MeSH
- vajíčko rostlin genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- kyseliny indoloctové MeSH
- proteiny huseníčku * MeSH
The fine tuning of hormone (e.g., auxin and gibberellin) levels and hormone signaling is required for maintaining normal embryogenesis. Embryo polarity, for example, is ensured by the directional movement of auxin that is controlled by various types of auxin transporters. Here, we present pieces of evidence for the auxin-gibberellic acid (GA) hormonal crosstalk during embryo development and the regulatory role of the Arabidopsis thaliana Calcium-Dependent Protein Kinase-Related Kinase 5 (AtCRK5) in this regard. It is pointed out that the embryogenesis of the Atcrk5-1 mutant is delayed in comparison to the wild type. This delay is accompanied with a decrease in the levels of GA and auxin, as well as the abundance of the polar auxin transport (PAT) proteins PIN1, PIN4, and PIN7 in the mutant embryos. We have previously showed that AtCRK5 can regulate the PIN2 and PIN3 proteins either directly by phosphorylation or indirectly affecting the GA level during the root gravitropic and hypocotyl hook bending responses. In this manuscript, we provide evidence that the AtCRK5 protein kinase can in vitro phosphorylate the hydrophilic loops of additional PIN proteins that are important for embryogenesis. We propose that AtCRK5 can govern embryo development in Arabidopsis through the fine tuning of auxin-GA level and the accumulation of certain polar auxin transport proteins.
- Klíčová slova
- Arabidopsis thaliana, Calcium-Dependent Protein Kinase-Related Kinase (CRK), GA3, auxin gradient, embryogenesis, polar auxin transport (PAT) proteins,
- MeSH
- Arabidopsis růst a vývoj metabolismus MeSH
- ELISA MeSH
- gibereliny analýza metabolismus MeSH
- klíčení * MeSH
- kyseliny indoloctové metabolismus MeSH
- membránové transportní proteiny genetika metabolismus MeSH
- protein-serin-threoninkinasy metabolismus MeSH
- proteiny huseníčku genetika metabolismus MeSH
- receptory buněčného povrchu metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- semena rostlinná anatomie a histologie růst a vývoj metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- CRK5 protein, Arabidopsis MeSH Prohlížeč
- gibberellic acid MeSH Prohlížeč
- gibereliny MeSH
- kyseliny indoloctové MeSH
- membránové transportní proteiny MeSH
- protein-serin-threoninkinasy MeSH
- proteiny huseníčku MeSH
- receptory buněčného povrchu MeSH
Seedling establishment following germination requires the fine tuning of plant hormone levels including that of auxin. Directional movement of auxin has a central role in the associated processes, among others, in hypocotyl hook development. Regulated auxin transport is ensured by several transporters (PINs, AUX1, ABCB) and their tight cooperation. Here we describe the regulatory role of the Arabidopsis thaliana CRK5 protein kinase during hypocotyl hook formation/opening influencing auxin transport and the auxin-ethylene-GA hormonal crosstalk. It was found that the Atcrk5-1 mutant exhibits an impaired hypocotyl hook establishment phenotype resulting only in limited bending in the dark. The Atcrk5-1 mutant proved to be deficient in the maintenance of local auxin accumulation at the concave side of the hypocotyl hook as demonstrated by decreased fluorescence of the auxin sensor DR5::GFP. Abundance of the polar auxin transport (PAT) proteins PIN3, PIN7, and AUX1 were also decreased in the Atcrk5-1 hypocotyl hook. The AtCRK5 protein kinase was reported to regulate PIN2 protein activity by phosphorylation during the root gravitropic response. Here it is shown that AtCRK5 can also phosphorylate in vitro the hydrophilic loops of PIN3. We propose that AtCRK5 may regulate hypocotyl hook formation in Arabidopsis thaliana through the phosphorylation of polar auxin transport (PAT) proteins, the fine tuning of auxin transport, and consequently the coordination of auxin-ethylene-GA levels.
- Klíčová slova
- Arabidopsis thaliana, Ca2+/calmodulin-dependent kinase-related kinases (CRKs), polar auxin transport (PAT) proteins, GA3, auxin gradient, ethylene, skotomorphogenesis,
- MeSH
- Arabidopsis účinky léků fyziologie MeSH
- biologické markery MeSH
- fenotyp MeSH
- fosforylace MeSH
- hypokotyl fyziologie MeSH
- klíčení MeSH
- morfogeneze * účinky léků genetika MeSH
- protein-serin-threoninkinasy metabolismus MeSH
- proteiny huseníčku metabolismus MeSH
- receptory buněčného povrchu metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- reportérové geny MeSH
- signální transdukce MeSH
- vývoj rostlin * účinky léků genetika MeSH
- xantony farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- biologické markery MeSH
- CRK5 protein, Arabidopsis MeSH Prohlížeč
- GA3 compound MeSH Prohlížeč
- protein-serin-threoninkinasy MeSH
- proteiny huseníčku MeSH
- receptory buněčného povrchu MeSH
- xantony MeSH
