Ondrej Novak

Ondrej Novak
Palacký University Olomouc · Laboratory of Growth Regulators

Assoc. Prof.

About

476
Publications
95,411
Reads
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15,265
Citations
Introduction
Ondrej Novak currently works at the Laboratory of Growth Regulators, Palacký University Olomouc & Institute of Experimental Botany CAS. Ondrej does research in Analytical Chemistry, Plant Physiology and Molecular Biology.
Additional affiliations
July 2018 - present
Institute of Experimental Botany AS CR
Position
  • Senior Researcher
June 2018 - present
Palacký University Olomouc
Position
  • Professor (Associate)
January 2014 - December 2018
Centre of Region Haná for Biotechnological and Agricultural Research Crop Research Institute
Position
  • Head of Department
Education
September 2001 - July 2006
Palacký University Olomouc
Field of study
  • Botany
September 1994 - September 1999
Palacký University Olomouc
Field of study
  • Analytical Chemistry

Publications

Publications (476)
Article
Full-text available
Cytokinins (CKs) play a crucial role in many physiological and developmental processes at the levels of individual plant components (cells, tissues, and organs) and by coordinating activities across these parts. High-resolution measurements of intracellular CKs in different plant tissues can therefore provide insights into their metabolism and mode...
Article
Full-text available
Coordination of cell division and pattern formation is central to tissue and organ development, particularly in plants where walls prevent cell migration. Auxin and cytokinin are both critical for division and patterning, but it is unknown how these hormones converge upon tissue development. We identify a genetic network that reinforces an early em...
Article
Full-text available
Cytokinins are a major group of phytohormones regulating plant growth, development and stress responses. However, in contrast to the well-defined polar transport of auxins, the molecular basis of cytokinin transport is poorly understood. Here we show that an ATP-binding cassette transporter in Arabidopsis, AtABCG14, is essential for the acropetal (...
Article
The plant hormone auxin is believed to influence almost every aspect of plant growth and development. Auxin transport, biosynthesis and degradation combine to form gradients of the hormone that influence a range of key developmental and environmental response processes. There is abundant genetic evidence for the existence of multiple pathways for a...
Article
The rice carotenoid cleavage dioxygenase OsZAS was described to produce zaxinone, a novel plant‐growth promoting apocarotenoid. A zas mutant line showed a reduced arbuscular mycorrhizal (AM) colonization but the mechanisms underlying this behavior are unknown. Here, we investigated how OsZAS and exogenous zaxinone treatment regulate mycorrhization....
Article
Full-text available
This (two-season) study was undertaken to assess the involvement of gibberellins (GAs), cytokinins (CKs), and auxins (AX) in dormancy of the sweet cherry buds ‘Summit’. Our hypothesis consisted in the assumption that representatives of these hormone groups are able to mark the transition between different dormancy phases. Changes in the transition...
Preprint
C-TERMINALLY ENCODED PEPTIDE (CEP) and cytokinin hormones act over short and long distances to control plant responses to environmental cues. CEP and cytokinin pathway mutants share phenotypes, however, it is not known if these pathways intersect. We show that CEP and cytokinin signalling converge on CEP DOWNSTREAM (CEPD) glutaredoxins to inhibit p...
Article
The vacuole has a space-filling function, allowing a particularly rapid plant cell expansion with very little increase in cytosolic content (Löfke et al., 2015; Scheuring et al., 2016; Dünser et al., 2019). Despite its importance for cell size determination in plants, very little is known about the mechanisms that define vacuolar size. Here, we sho...
Article
Full-text available
Background Bread wheat ( Triticum aestivum ) is a major source of nutrition globally, but yields can be seriously compromised by water limitation. Redistribution of growth between shoots and roots is a common response to drought, promoting plant survival, but reducing yield. Gibberellins (GAs) are necessary for shoot and root elongation, but roots...
Article
Full-text available
The factors underlying the plant collapse of certain melon-pumpkin graft combinations are not fully understood. Our working hypothesis was that impairment of photoassimilates transport in incompatible combinations induces an imbalance in the homeostasis of root auxin (indole-3-acetic acid; IAA) and of cytokinins, probably triggering plant collapse....
Preprint
Full-text available
Cytokinin and auxin are plant hormones that coordinate many aspects of plant development. Their interactions in plant underground growth are well established, occurring at the levels of metabolism, signaling, and transport. Unlike many plant hormone classes, cytokinins are represented by more than one active molecule. Multiple mutant lines, blockin...
Article
Full-text available
Molecular responses of plants to natural phytotoxins comprise more general and compound-specific mechanisms. How phytotoxic chalcones and other flavonoids inhibit seedling growth was widely studied, but how they interfere with seed germination is largely unknown. The dihydrochalcone and putative allelochemical myrigalone A (MyA) inhibits seed germi...
Article
Full-text available
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 respo...
Article
State‐of‐the‐art technology based on organic electronics can be used as a flow‐free delivery method for organic substances with high spatial resolution. Such highly targeted drug micro applications can be used in plant research for the regulation of physiological processes on tissue and cellular levels. Here, for the first time, an organic electron...
Preprint
European aspen ( Populus tremula L.) undergoes a coordinated senescence program during autumn; however, it is not known what exactly triggers it. To identify the cellular program leading to senescence, we utilized natural variation among Swedish aspen genotypes in a common garden to study senescence timing and the underlying changes in leaf phytoho...
Article
Full-text available
Fluctuating environmental conditions trigger adaptive responses in plants, which are regulated by phytohormones. During photoperiod stress caused by a prolongation of the light period, cytokinin (CK) has a protective function. Auxin often acts as an antagonist of CK in developmental processes and stress responses. Here, we investigated the regulati...
Article
Full-text available
Cytokinin has strong connections to development and a growing role in abiotic stress response. Here we shown that Cytokinin Response Factor 2 (CRF2) is additionally involved in salt (NaCl) stress response. CRF2 promoter‐GUS expression indicate CRF2 involvement in salt stress response as well as previously known cytokinin‐response. Interestingly, CR...
Article
Full-text available
Plant secondary growth, which is the basis of wood formation, includes the production of secondary xylem, which is derived from meristematic cambium cells embedded in vascular tissue. Here, we identified an important role for the Arabidopsis thaliana (Arabidopsis) AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED 15 (AHL15) transcriptional regulator in co...
Article
Indole‐3‐acetic acid (IAA) controls a plethora of developmental processes. Thus, regulation of their levels is of great relevance for plant performance. Cellular IAA concentration is a result of its transport, biosynthesis and various pathways for IAA inactivation, including oxidation and conjugation. Group II members of the GRETCHEN HAGEN 3 (GH3)...
Article
Full-text available
Acclimation to salt stress in plants is regulated by complex signaling pathways involving endogenous phytohormones. The signaling role of salicylic acid (SA) in regulating crosstalk between endogenous plant growth regulators’ levels was investigated in barley (Hordeum vulgare L. ‘Ince’; 2n = 14) leaves and roots under salt stress. Salinity (150 and...
Preprint
Background Bread wheat ( Triticum aestivum ) is a major source of nutrition globally, but yields can be seriously compromised by water limitation. Redistribution of growth between shoots and roots is a common response to drought, promoting plant survival, but reducing yield. Gibberellins (GAs) are necessary for shoot and root elongation, but roots...
Article
Full-text available
Soil salinization is increasing globally, driving a reduction in crop yields that threatens food security. Salinity stress reduces plant growth by exerting two stresses on plants: rapid shoot ion-independent effects which are largely osmotic and delayed ionic effects that are specific to salinity stress. In this study we set out to delineate the os...
Article
Full-text available
Mitochondrial adrenodoxins (ADXs) are small iron–sulfur proteins with electron transfer properties. In animals, ADXs transfer electrons between an adrenodoxin reductase (ADXR) and mitochondrial P450s, which is crucial for steroidogenesis. Here we show that a plant mitochondrial steroidogenic pathway, dependent on an ADXR–ADX–P450 shuttle, is essent...
Article
Full-text available
The superior properties of silver nanoparticles (AgNPs) has resulted in their broad utilization worldwide, but also the risk of irreversible environment infestation. The plant cuticle and cell wall can trap a large part of the nanoparticles and thus protect the internal cell structures, where the cytoskeleton, for example, reacts very quickly to th...
Article
Full-text available
Under the global warming scenario, obtaining plant material with improved tolerance to abiotic stresses is a challenge for afforestation programs. In this work, maritime pine (Pinus pinaster Aiton) plants were produced from somatic embryos matured at different temperatures (18, 23, or 28 °C, named after M18, M23, and M28, respectively) and after 2...
Article
Full-text available
The CLAVATA pathway is a key regulator of stem cell function in the multicellular shoot tips of Arabidopsis, where it acts via the WUSCHEL transcription factor to modulate hormone homeostasis. Broad scale evolutionary comparisons have shown that CLAVATA is a conserved regulator of land plant stem cell function, but CLAVATA acts independently of WUS...
Article
Full-text available
Improving yield, nutritional value and tolerance to abiotic stress are major targets of current breeding and biotechnological approaches that aim at increasing crop production and ensuring food security. Metabolic engineering of carotenoids, the precursor of vitamin-A and plant hormones that regulate plant growth and response to adverse growth cond...
Article
Full-text available
Background The plant hormone auxin is a major coordinator of plant growth and development in response to diverse environmental signals, including nutritional conditions. Sole ammonium (NH 4 ⁺ ) nutrition is one of the unique growth-suppressing conditions for plants. Therefore, the quest to understand NH 4 ⁺ -mediated developmental defects led us to...
Preprint
The vacuole has a space-filling function, allowing a particularly rapid plant cell expansion with very little increase in cytosolic content (Loefke et al., 2015; Scheuring et al., 2016; Duenser et al., 2019). Despite its importance for cell size determination in plants, very little is known about the mechanisms that define vacuolar size. Here we sh...
Article
Full-text available
The plant nucleus plays an irreplaceable role in cellular control and regulation by auxin (indole-3-acetic acid, IAA) mainly because canonical auxin signaling takes place here. Auxin can enter the nucleus from either the endoplasmic reticulum or cytosol. Therefore, new information about the auxin metabolome (auxinome) in the nucleus can illuminate...
Article
Full-text available
During plant development, a precise balance of cytokinin is crucial for correct growth and patterning, but it remains unclear how this is achieved across different cell types and in the context of a growing organ. Here we show that, in the root apical meristem, the TMO5/LHW complex increases active cytokinin levels via two cooperatively acting enzy...
Article
General volatile anaesthetics (GVA) inhibit electrical signal propagation in animal neurons. Although plants do not have neurons, they generate and propagate electrical signals systemically from a local damaged leaf to neighbouring leaves. This systemic electrical signal propagation is mediated by ligand-gated glutamate receptor-like (GLR) channels...
Preprint
Chemical inhibitors are often implemented for the functional characterization of genes to overcome the limitations associated with genetic approaches. Although being a powerful tool, off-target effects of these inhibitors are easily overlooked in a complex biological setting. Here we illustrate the implications of such secondary effects by focusing...
Article
Full-text available
Using plant growth regulators to alter cytokinin homeostasis with the aim of enhancing endogenous cytokinin levels has been proposed as a strategy to increase yields in wheat and barley. The plant growth regulators INCYDE and CPPU inhibit the cytokinin degrading enzyme cytokinin oxidase/dehydrogenase (CKX), while TD-K inhibits the process of senesc...
Preprint
Full-text available
Indole-3-acetic acid (IAA) controls a plethora of developmental processes. Thus, regulation of their levels is of great relevance for plant performance. Cellular IAA concentration depends on the combined result of its transport, biosynthesis and various redundant pathways to inactivate IAA, including oxidation and conjugation. Group II members of t...
Article
Full-text available
Underdeveloped (small) embryos embedded in abundant endosperm tissue, and thus having morphological (MD) or morphophysiological (MPD) dormancy, are considered to be the ancestral state in seed dormancy evolution. This trait is retained in the Apiaceae family which provides excellent model systems to study the underpinning mechanisms. We investigate...
Article
Full-text available
The endoplasmic reticulum (ER) is an extensive network of intracellular membranes. Its major functions include proteosynthesis, protein folding, post-transcriptional modification and sorting of proteins within the cell, and lipid anabolism. Moreover, several studies have suggested that it may be involved in regulating intracellular auxin homeostasi...
Article
Full-text available
Size control is a fundamental question in biology, showing incremental complexity in plants, whose cells possess a rigid cell wall. The phytohormone auxin is a vital growth regulator with central importance for differential growth control. Our results indicate that auxin-reliant growth programs affect the molecular complexity of xyloglucans, the ma...
Article
Full-text available
Using pea as our model crop, we sought to understand the regulatory control over the import of sugars and amino acids into the developing seeds and its importance for seed yield and quality. Transgenic peas simultaneously overexpressing a sucrose transporter and an amino acid transporter were developed. Pod walls, seed coats, and cotyledons were an...
Article
Full-text available
Adventitious rooting is a de novo organogenesis process that enables plants to propagate clonally and cope with environmental stresses. Adventitious root initiation (ARI) is controlled by interconnected transcriptional and hormonal networks, but there is little knowledge of the genetic and molecular programs orchestrating these networks. Thus, we h...
Preprint
Full-text available
Plants continuously adjust the rate at which new organs are produced in accordance with endogenous and environmental signals. Therefore, a multitude of signaling pathways converge to modulate stem cell activity. We have shown previously, that the TOR kinase network integrates metabolic- and light signals to control expression of WUSCHEL, a transcri...
Article
Full-text available
Salt and osmotic stress are the main abiotic stress factors affecting plant root growth and architecture. We investigated the effect of salt (100 mM NaCl) and osmotic (200 mM mannitol) stress on the auxin metabolome by UHPLC-MS/MS, auxin distribution by confocal microscopy, and transcript levels of selected genes by qRT-PCR in Arabidopsis thaliana...
Preprint
Full-text available
Pectins occur in primary cell walls and consist of multiblock co‐polymers among which homogalacturonan (HG) is the simplest and most abundant form. Methylesterification patterns of HG are tuned by pectin methylesterases (PMEs), the activities of which are controlled by specific inhibitors (PMEIs). By impacting cell wall mechanical properties, PME‐m...
Article
Full-text available
Plants in temperate regions have evolved mechanisms that enable them to survive sudden temperature drops. Experiments with plants grown in long-day conditions, in which they are most sensitive to freezing stress, indicate that the cold acclimation mechanism is light-dependent and does not fully operate under low light intensity. However, winter ann...
Article
Full-text available
Eukaryotic organisms are equipped with quality-control mechanisms that survey protein folding in the endoplasmic reticulum (ER) and remove non-native proteins by ER-associated degradation (ERAD). Recent research has shown that cytokinin-degrading CKX proteins are subjected to ERAD during plant development. The mechanisms of plant ERAD, including th...
Preprint
Full-text available
Plant shape is determined by the activity of stem cells in the growing tips, and evolutionary changes in shape are linked to changes in stem cell function. The CLAVATA pathway is a key regulator of stem cell function in the multicellular shoot tips of Arabidopsis, acting via the WUSCHEL transcription factor to modulate hormone homeostasis. Broad sc...
Article
Auxin homeostasis and signaling affect a broad range of developmental processes in plants. The interplay between HSP90 and auxin signaling is channeled through the chaperoning capacity of the HSP90 on the TIR1 auxin receptor. The sophisticated buffering capacity of the HSP90 system through the interaction with diverse signaling protein components d...
Article
Terrestrial carnivorous plants of genera Drosera, Dionaea and Nepenthes within the order Caryophyllales employ jasmonates for the induction of digestive processes in their traps. Here, we focused on two aquatic carnivorous plant genera with different trapping mechanism from distinct families and orders: Aldrovanda (Droseraceae, Caryophyllales) with...
Article
Two wheat genotypes forming high and low biomass (HB and LB), exhibiting differential expression of an isoflavone reductase-like (IRL) gene, and resulting in contrasting grain yield under heat stress field conditions, were analyzed in detail for their responses under controlled heat and elevated CO2 conditions. Significant differences in IRL expres...
Article
Two wheat genotypes forming high and low biomass (HB and LB), exhibiting differential expression of an isoflavone reductase-like (IRL) gene, and resulting in contrasting grain yield under heat stress field conditions, were analyzed in detail for their responses under controlled heat and elevated CO2 conditions. Significant differences in IRL expres...
Article
Together with auxin transport, auxin metabolism is a key determinant of auxin signalling output by plant cells. Enzymatic machinery involved in auxin metabolism is subject to regulation based on numerous inputs, including the concentration of auxin itself. Therefore, experiments characterizing altered auxin availability and subsequent changes in au...
Article
Full-text available
The spatial location and timing of plant developmental events are largely regulated by the well balanced effects of auxin and cytokinin phytohormone interplay. Together with transport, localized metabolism regulates the concentration gradients of their bioactive forms, ultimately eliciting growth responses. In order to explore the dynamics of auxin...
Preprint
Full-text available
Improving yield, nutritional value and tolerance to abiotic stress are major targets of current breeding and biotechnological approaches that aim at increasing crop production and ensuring food security. Metabolic engineering of carotenoids, the precursor of Vitamin-A and plant hormones that regulate plant growth and response to adverse growth cond...
Article
Full-text available
Instrumentation for flow cytometry and sorting is designed around the assumption that samples are single‐cell suspensions. However, with few exceptions, higher plants comprise complex multicellular tissues and organs, in which the individual cells are held together by shared cell walls. Single‐cell suspensions can be obtained through digestion of t...