Filip Vandenbussche

Deroose Plants · Labo

Inflorescence movements in response to natural gradients of sunlight are frequently observed in the plant kingdom and are suggested to contribute to reproductive success. Although the physiological and molecular bases of light-mediated tropisms in vegetative organs have been thoroughly investigated, the mechanisms that control inflorescence orienta...

The force of gravity is a constant environmental factor. Plant shoots respond to gravity through negative gravitropism and gravity resistance. These responses are essential for plants to direct the growth of aerial organs away from the soil surface after germination and to keep an upright posture above ground. We took advantage of the effect of bra...

Ultraviolet (UV) radiation directly affects plants and microorganisms, but also alters the species-specific interactions between them. The distinct bands of UV radiation, UV-A, UV-B, and UV-C have different effects on plants and their associated microorganisms. While UV-A and UV-B mainly affect morphogenesis and phototropism, UV-B and UV-C strongly...

Atmospheric CO2 levels are rising rapidly due to anthropogenic activities. Although plants require CO2 to fuel photosynthesis, the relationship between CO2 and plant growth is complex. In phytotrons elevated CO2 was shown to stimulate growth of Arabidopsis thaliana. In nature, there is, however, a constant variation in temperature, the availability...

Many aspects of light-controlled metabolism and development of plants depend on hormonal pathways. Here, a method is described to identify such hormonal dependence in light-regulated processes. A number of compounds—hormones and chemicals which interfere with hormonal pathways—are listed because of their usefulness in pharmacological treatment expe...

In the course of evolution, plants have developed mechanisms to orient their organs towards the incoming light. At the seedling stage, positive phototropism is mainly regulated by phototropin photoreceptors in blue and ultraviolet wavelengths. Contrasting with this, we report that UV RESISTANCE LOCUS 8 (UVR8) serves as predominant photoreceptor of...

Shoot gravitropism is essential for plants to direct the growth of above-ground tissues towards the soil surface after germination. Brassinosteroids influence shoot gravitropism and we used this as a tool to untangle the function of cell wall polymers during etiolated shoot growth. The ability of etiolated Arabidopsis seedlings to grow upwards was...

The UV RESISTANCE LOCUS 8 (UVR8) photoreceptor controls UV-B mediated photomorphogenesis in Arabidopsis. The aim of this work is to collect and characterize different molecular reporters of photomorphogenic UV-B responses. Browsing available transcriptome databases, we identified sets of genes responding specifically to this radiation and are contr...

UV-B phototropism in etiolated Arabidopsis seedlings has only been shown recently and needs further exploration. Here we elaborate on how to generate a customized setup with a unilateral UV-B light source, the required plant materials, different growth substrates, and a framework for data analysis.

Plants perceive ultraviolet-B (UV-B) radiation through the UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8), and initiate regulatory responses via associated signalling networks, gene expression and metabolic pathways. Various regulatory adaptations...

Key message: Silver ions increase plasma membrane permeability for water and small organic compounds through their stimulatory effect on plasma membrane calcium channels, with subsequent modulation of intracellular calcium levels and ion homeostasis. The action of silver ions at the plant plasma membrane is largely connected with the inhibition of...

Significance Ethylene is a gaseous hormone that controls plant life throughout development. Being a simple hydrophobic molecule, it can freely enter cells; therefore, the cell type specificity of its action is challenging. By means of tissue-specific expression of two negative regulators of the signaling cascade, we selectively disrupted the ethyle...

The Elongator complex interacts with RNA polymerase II and via histone acetylation and DNA demethylation facilitates epigenetically the transcription of genes involved in diverse processes in plants, including growth, development, and immune response. Recently, we have shown that the Elongator complex promotes hypocotyl elongation and photomorphoge...

Adventitious root formation is essential for cutting propagation of diverse species; however, until recently little was known about its regulation. Strigolactones and ethylene have both been shown to inhibit adventitious roots and it has been suggested that ethylene interacts with strigolactones in root hair elongation. We have investigated the int...

Ultraviolet B light (UV-B, 280–315 nm) is the shortest wavelength of the solar spectrum reaching the surface of the Earth. It has profound effects on plants, ranging from growth regulation to severe metabolic changes. Low level UV-B mainly causes photomorphogenic effects while higher levels can induce stress, yet these effects tend to overlap. Here...

Plant movements in response to directional solar radiation, known as “heliotropism” are frequently observed in nature. Although there is a considerable amount of literature on these movements in vegetative organs, knowledge about heliotropic responses in flowers and inflorescences is relatively limited. Here we comprehensively review studies on thi...

The volatile two-carbon hormone ethylene acts in concert with an array of signals to affect etiolated seedling development. From a chemical screen, we isolated a quinoline carboxamide designated ACCERBATIN (AEX) that exacerbates the 1-aminocyclopropane-1-carboxylic acid-induced triple response, typical for ethylene-treated seedlings in darkness. Ph...

The Elongator complex (hereafter Elongator) promotes RNA polymerase II-mediated transcript elongation through epigenetic activities such as histone acetylation. Elongator regulates growth, development, immune response and sensitivity to drought and abscisic acid. We demonstrate that elo mutants exhibit defective hypocotyl elongation but have a norm...

Main conclusion: This review highlights that the auxin gradient, established by local auxin biosynthesis and transport, can be controlled by ethylene, and steers seedling growth. A better understanding of the mechanisms in Arabidopsis will increase potential applications in crop species. In dark-grown Arabidopsis seedlings, exogenous ethylene trea...

In the light of increasing evidence that plant growth and development depend on signals perceived in distinct cell types where hormonal inputs are transformed into orchestrated responses triggering a plethora of physiological processes, we reflect on the case of ethylene signaling. Experimental approaches to address cell type-specificity of the eth...

Ultraviolet B (UV-B) light is a portion of solar radiation that has significant effects on the development and metabolism of plants. Effects of UV-B on plants can be classified into photomorphogenic effects and stress effects. These effects largely rely on the control of, and interactions with, hormonal pathways. The fairly recent discovery of the...

Ultraviolet B (UV-B) light is a part of the solar radiation which has significant effects on plant morphology, even at low doses. In Arabidopsis, many of these morphological changes have been attributed to a specific UV-B receptor, UV resistance locus 8 (UVR8). Recent findings showed that next to phototropin regulated phototropism, UVR8 mediated si...

In the light of increasing evidence that plant growth and development depend on signals perceived in distinct cell types where hormonal inputs are transformed into orchestrated responses triggering a plethora of physiological processes, we reflect on the case of ethylene signaling. Experimental approaches to address cell type-specificity of the eth...

Plants are very well adapted to growth in ultraviolet-B (UV-B) containing light. In Arabidopsis thaliana, many of these adaptations are mediated by the UV-B receptor UV RESISTANCE LOCUS 8 (UVR8). Using small amounts of supplementary UV-B light, we observed changes in the shape of rosette leaf blades. Wild type plants show more pronounced epinasty o...

To date, the main long-standing model explaining phototropic bending is that of Cholodny (1927) and Went (1926), which suggests that the lateral distribution of a growth hormone regulates phototropism and which is supported by a substantial amount of molecular and cell biological evidence (Christie et al., 2011; Ding et al., 2011; Christie and Murp...

Anthropogenic activities cause metal pollution worldwide. Plants can absorb and accumulate these metals through their root system, inducing stress as a result of excess metal concentrations inside the plant. Ethylene is a regulator of multiple plant processes, and is affected by many biotic and abiotic stresses. Increased ethylene levels have been...

Plants reorient their growth towards light to optimize photosynthetic light capture, a process known as phototropism. Phototropins are the photoreceptors essential for phototropic growth towards blue and ultraviolet-A (UV-A) light. Here we detail a phototropic response towards UV-B in etiolated Arabidopsis seedlings. We report that early differenti...

Germination of Arabidopsis seeds in darkness induces apical hook development, based on a tightly regulated differential growth coordinated by a multiple hormone cross-talk. Here, we endeavoured to clarify the function of brassinosteroids (BRs) and cross-talk with ethylene in hook development.An automated infrared imaging system was developed to stu...

Small molecules which act as hormone agonists or antagonists represent useful tools in fundamental research and are widely applied in agriculture to control hormone effects. High-throughput screening of large chemical compound libraries has yielded new findings in plant biology, with possible future applications in agriculture and horticulture. To...

Ethylene is a gaseous plant hormone affecting multiple aspects of plant development. Besides playing a primary role in ripening, abscission, and senescence, it controls many aspects of vegetative growth and plays a crucial role in plant stress responses. Small molecules which act as ethylene agonists or antagonists have been used both in fundamenta...

The Root of the Problem The quiescent center (QC) within the root meristem plays a key role as a stem cell organizer to sustain the root stem cell niche. The QC cells execute a dual role: prevention of the differentiation of neighboring stem cells, and maintenance of the root structure by undergoing only occasional cell division. The mechanisms tha...

Growth and biomechanics of etiolated hypocotyls from Arabidopsis thaliana lines overexpressing xyloglucan endotransglucosylase/hydrolase AtXTH18, AtXTH19, AtXTH20, and PttXET16-34 were studied. Overexpression of AtXTH18, AtXTH19, and AtXTH20 stimulated growth of hypocotyls, while PttXET16-34 overexpression did not show this effect. In vitro extensi...

Premise of the study: To reach favorable conditions for photosynthesis, seedlings grow upward when deprived of light upon underground germination. To direct their growth, they use their negative gravitropic capacity. Negative gravitropism is under tight control of multiple hormones. Methods: By counting the number of standing plants in a populat...

Image analysis of Arabidopsis thaliana rosettes is an important non destructive method for studying plant growth. Some work on automatic rosette measurement using image analysis has been proposed in the past, but is generally restricted to be used only in combination with specific high throughput monitoring systems. We introduce Rosette Tracker, a...

Registration of multispectral images remains a challenging task due to the lack of stable feature points. Methods based on intensities are generally more robust for multi-modal image registration, but are computationally demanding or are restrictive to the transformation model allowed in the registration. This paper proposes a new registration fram...

The vegetative development of plants is strongly dependent on the action of phytohormones. For over a century, the effects of ethylene on plants have been studied, illustrating the profound impact of this gaseous hormone on plant growth, development and stress responses. Ethylene signaling is under tight self-control at various levels. Feedback reg...

Ethylene has a profound effect on the shape of plants. It determinesmany aspects of vegetative development by interacting with other hormones. Foremost, ethylene relies on a tight collaboration with auxin to influence plant growth and can stimulate or inhibit elongation of roots and shoots. This stimulatory or inhibitory action depends on the speci...

The root phenotype of an Arabidopsis (Arabidopsis thaliana) mutant of CHITINASE-LIKE1 (CTL1), called arm (for anion-related root morphology), was previously shown to be conditional on growth on high nitrate, chloride, or sucrose. Mutants grown under restrictive conditions displayed inhibition of primary root growth, radial swelling, proliferation o...

In the current model of gravitropism, negative gravitropic (upward) growth of the shoot of a dicotyledonous plant involves sedimentation of starch-containing plastids (statoliths) in the endodermis (starch sheath). Here we show that high levels of brassinosteroids (BRs) counteract gravitropic growth, while BR deficiency enhances gravitropism irresp...

The apical hook develops in the upper part of the hypocotyl when seeds buried in the soil germinate, and serves to protect cotyledons and the shoot apical meristem from possible damage caused by pushing through the soil. The curvature is formed through differential cell growth that occurs at the two opposite sides of the hypocotyl, and it is establ...

In Arabidopsis (Arabidopsis thaliana; Columbia-0) roots, the so-called zone of cell elongation comprises two clearly different domains: the transition zone, a postmeristematic region (approximately 200-450 μm proximal of the root tip) with a low rate of elongation, and a fast elongation zone, the adjacent proximal region (450 μm away from the root...

The phytohormone ethylene differentially regulates plant architecture and growth in both a light- and nutrient-dependent fashion. The modulation of plant development by ethylene in response to both external and internal signals can also generate tissue-specific differential responses. Here, we report that XAP5 CIRCADIAN TIMEKEEPER (XCT) is involved...

Dark-grown dicotyledonous seedlings form a hook-like structure at the top of the hypocotyl, which is controlled by the hormones auxin and ethylene. Hook formation is dependent on an auxin signal gradient, whereas hook exaggeration is part of the triple response provoked by ethylene in dark-grown Arabidopsis seedlings. Several other hormones and lig...

The apical hook of dark-grown Arabidopsis seedlings is a simple structure that develops soon after germination to protect the meristem tissues during emergence through the soil and that opens upon exposure to light. Differential growth at the apical hook proceeds in three sequential steps that are regulated by multiple hormones, principally auxin a...

In eukaryotes, transcription of protein-encoding genes is strongly regulated by posttranslational modifications of histones that affect the accessibility of the DNA by RNA polymerase II (RNAPII). The Elongator complex was originally identified in yeast as a histone acetyltransferase (HAT) complex that activates RNAPII-mediated transcription. In Ara...

A role for cortical microtubules, cellulose microfibrils and cell wall enzymes in the control of plant cell expansion has been suggested for several decades, but has not yet been proven in any system. Arabidopsis root epidermis is an ideal tissue to test this hypothesis, and consequently is the subject of many recent reports. Microtubules of epider...

Since the second half of the 1990s, a large number of genome-wide analyses have been described that study gene expression at the transcript level. To this end, two major strategies have been adopted, a first one relying on hybridization techniques such as microarrays, and a second one based on sequencing techniques such as serial analysis of gene e...

Ethylene and gibberellins (GAs) are known to influence plant growth by mutual cross-talk and by interaction with other hormones. Transcript meta-analysis shows that GA and ethylene metabolism genes are expressed in the majority of plant organs. Both GAs and the ethylene precursor 1-amino-cyclopropane-1-carboxylic acid (ACC) may thus be synthesized...

This file contains a list of the TIGR contigs (gene indices), homologous to Arabidopsis thaliana RGA, used in the evolutionary trees with indication of the organism.

This file contains a list of the TIGR contigs (gene indices), homologous to Arabidopsis thaliana SLEEPY1, used in the evolutionary trees with indication of the organism.

This file contains the numbers of the ESTs and contigs used for reconstructing the Selaginella and Physcomitrella homologues of the Arabidopsis thaliana SLEEPY1 gene.

This file contains the numbers of the ESTs and contigs used for reconstructing the Selaginella and Physcomitrella homologues of the Arabidopsis thaliana GA receptor GID1.

This file contains a list of the TIGR contigs (gene indices), homologous to the Arabidopsis thaliana GID1 GA receptor, used in the evolutionary trees with indication of the organism.

This file contains the numbers of the ESTs and contigs used for reconstructing the Selaginella and Physcomitrella homologues of the Arabidopsis thaliana RGA gene.

IntroductionEthylene biosynthesisEthylene signal transductionA complex networkAcknowledgements

The plant hormone ethylene plays a pivotal role in steering various processes by regulating the biosynthesis, distribution, or signal transduction of other hormones. Ethylene also mediates the effects of other hormones. Similarly, hormones control the ethylene synthesis and signalling pathway. Eventually, integration of this network of signals lead...

Cryptochromes are blue light-sensing photoreceptors found in plants, animals, and humans. They are known to play key roles in the regulation of the circadian clock and in development. However, despite striking structural similarities to photolyase DNA repair enzymes, cryptochromes do not repair double-stranded DNA, and their mechanism of action is...