Karin Ljung

Karin Ljung
Swedish University of Agricultural Sciences | SLU · Department of Forest Genetics and Plant Physiology

About

301
Publications
79,491
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24,843
Citations
Citations since 2017
137 Research Items
12704 Citations
201720182019202020212022202305001,0001,5002,0002,500
201720182019202020212022202305001,0001,5002,0002,500
201720182019202020212022202305001,0001,5002,0002,500
201720182019202020212022202305001,0001,5002,0002,500

Publications

Publications (301)
Article
Full-text available
To maximise reproductive success, flowering plants must correctly time entry and exit from the reproductive phase. While much is known about mechanisms that regulate initiation of flowering, end-of-flowering remains largely uncharacterised. End-of-flowering in Arabidopsis (Arabidopsis thaliana) consists of quasi-synchronous arrest of inflorescences...
Article
Full-text available
ATP-Binding Cassette E (ABCE) proteins dissociate cytoplasmic ribosomes after translation terminates, and contribute to ribosome recycling, thus linking translation termination to initiation. This function has been demonstrated to be essential in animals, fungi, and archaea, but remains unexplored in plants. In most species, ABCE is encoded by a si...
Article
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
The 26S proteasome is a conserved multi-subunit machinery in eukaryotes. It selectively degrades ubiquitinated proteins, which in turn provides an efficient molecular mechanism to regulate numerous cellular functions and developmental processes. Here, we studied a new loss-of-function allele of RPN12a, a plant ortholog of the yeast and human struct...
Preprint
Full-text available
The initiation of lateral roots in Arabidopsis requires the accumulation of auxin in lateral root founder cells, yielding a local auxin maximum. The positioning of these auxin maxima along the primary root determines the density and spacing of lateral roots. The GOLVEN6 (GLV6) and GLV10 signaling peptides and their receptors have been established a...
Article
Full-text available
The size of plant organs is highly responsive to environmental conditions. The plant’s embryonic stem, or hypocotyl, displays phenotypic plasticity, in response to light and temperature. The hypocotyl of shade avoiding species elongates to outcompete neighboring plants and secure access to sunlight. Similar elongation occurs in high temperature. Ho...
Preprint
Full-text available
ATP-Binding Cassette E (ABCE) proteins dissociate cytoplasmic ribosomes after translation terminates, and contribute to ribosome recycling, thus linking translation termination to initiation. This function has been demonstrated to be essential in animals, fungi, and archaea, but remains unexplored in plants. In most species, ABCE is encoded by a si...
Article
Full-text available
Parasitic plants are globally prevalent pathogens that withdraw nutrients from their host plants using an organ known as the haustorium. The external environment including nutrient availability affects the extent of parasitism and to understand this phenomenon, we investigated the role of nutrients and found that nitrogen is sufficient to repress h...
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
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
Full-text available
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
Pollen grains become increasingly independent of the mother plant as they reach maturity through poorly understood developmental programs. We report that the hormone auxin is essential during barley pollen maturation to boost the expression of genes encoding almost every step of heterotrophic energy production pathways. Accordingly, auxin is necess...
Article
Full-text available
Photomorphogenic remodelling of seedling growth is a key developmental transition in the plant life cycle. The α/β‐hydrolase signalling protein KARRIKIN‐INSENSITIVE2 (KAI2), a close homologue of the strigolactone receptor DWARF14 (D14), is involved in this process, but it is unclear how the effects of KAI2 on development are mediated. Here, using a...
Article
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 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)...
Preprint
Full-text available
To maximise their reproductive success, flowering plants must correctly time their entry into and exit from the reproductive phase (flowering). While much is known about the mechanisms that regulate the initiation of flowering, the regulation of end-of-flowering remains largely uncharacterised. End-of-flowering in Arabidopsis thaliana consists of t...
Article
In plants, auxin transport and development are tightly coupled, just as hormone and growth responses are intimately linked in multicellular systems. Here we provide insights into uncoupling this tight control by specifically targeting the expression of TINY ROOT HAIR 1 (TRH1), a member of plant HAK/KUP/KT transporters that facilitate potassium upta...
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...
Preprint
Full-text available
Using microbial enzymes in transgenesis is a powerful means to introduce new functionalities in plants. Glucuronoyl esterase (GCE) is a microbial enzyme hydrolyzing the ester bond between lignin and 4-O-methyl-α-D-glucuronic acid present as a side chain of glucuronoxylan. This bond mediates lignin-carbohydrate complex (LCC) formation, considered as...
Article
Full-text available
The levels of the important plant growth regulator indole-3-acetic acid (IAA) are tightly controlled within plant tissues to spatiotemporally orchestrate concentration gradients that drive plant growth and development. Metabolic inactivation of bioactive IAA is known to participate in the modulation of IAA maxima and minima. IAA can be irreversibly...
Preprint
Arctic alpine species experience extended periods of cold and unpredictable conditions during flowering. Thus, often, alpine plants use both sexual and asexual means of reproduction to maximise fitness and ensure reproductive success. We used the arctic alpine perennial Arabis alpina to explore the role of prolonged cold exposure on adventitious ro...
Article
Full-text available
Plants have a high ability to cope with changing environments and grow continuously throughout life. However, the mechanisms by which plants strike a balance between stress response and organ growth remain elusive. Here, we found that DNA double-strand breaks enhance the accumulation of cytokinin hormones through the DNA damage signaling pathway in...
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
The photomorphogenic remodelling of seedling growth upon exposure to light is a key developmental transition in the plant life cycle. The α/β-hydrolase signalling protein KARRIKIN-INSENSITIVE2 (KAI2), a close homologue of the strigolactone receptor DWARF14 (D14), is involved in this process, and kai2 mutants have strongly altered seedling growth as...
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...
Article
Full-text available
Temperature passively affects biological processes involved in plant growth. It is therefore 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...
Preprint
Full-text available
The levels of the important plant growth regulator indole-3-acetic acid (IAA) are tightly controlled within plant tissues to spatiotemporally orchestrate concentration gradients that drive plant growth and development. Metabolic inactivation of bioactive IAA is known to participate in the modulation of IAA maxima and minima. IAA can be irreversibly...
Article
Full-text available
Ethylene aplenty signals soil compaction It's tough to drive a spade through compacted soil, and plant roots seem to have the same problem when growing in compacted ground. Pandey et al. found that the problem is not, however, one of physical resistance but rather inhibition of growth through a signaling pathway. The volatile plant hormone ethylene...
Article
Full-text available
The major natural auxin in plants, indole-3-acetic acid (IAA), orchestrates a plethora of developmental responses that largely depend on the formation of auxin concentration gradients within plant tissues. Together with inter- and intracellular transport, IAA metabolism-which comprises biosynthesis, conjugation, and degradation-modulates auxin grad...
Article
Full-text available
The phytohormone cytokinin plays a significant role in nearly all aspects of plant growth and development. Cytokinin signaling has primarily been studied in the dicot model Arabidopsis, with relatively little work done in monocots, which include rice (Oryza sativa) and other cereals of agronomic importance. The cytokinin signaling pathway is a phos...
Article
Temperature is one of the most impactful environmental factors to which plants adjust their growth and development. Although the regulation of temperature signaling has been extensively investigated for the aerial part of plants, much less is known and understood about how roots sense and modulate their growth in response to fluctuating temperature...
Article
Full-text available
Reaction wood (RW) formation is an innate physiological response of woody plants to counteract mechanical constraints in nature, reinforce structure and redirect growth toward the vertical direction. Differences and/or similarities between stem and root response to mechanical constraints remain almost unknown especially in relation to phytohormones...
Article
Full-text available
A key challenge in biology is to understand how the regional control of cell growth gives rise to final organ forms. Plant leaves must coordinate growth along both the proximodistal and mediolateral axes to produce their final shape. However, the cell-level mechanisms controlling this coordination remain largely unclear. Here, we show that, in A. t...
Article
Full-text available
The plant hormone auxin is a key factor for regulation of plant development, and this function was most likely reinforced during early land plant evolution. We have extended the available tool box to allow detailed studies of how auxin biosynthesis and responses are regulated in moss reproductive organs, their stem cells and gametes to better eluci...
Article
Full-text available
Cytokinins are mobile multifunctional plant hormones with roles in development and stress resilience. Although their Histidine Kinase receptors are substantially localised to the endoplasmic reticulum, cellular sites of cytokinin perception and importance of spatially heterogeneous cytokinin distribution continue to be debated. Here we show that cy...
Article
Full-text available
Morphological variation is the basis of natural diversity and adaptation. For example, angiosperms (flowering plants) evolved during the Cretaceous period more than 100 mya and quickly colonized terrestrial habitats [1]. A major reason for their astonishing success was the formation of fruits, which exist in a myriad of different shapes and sizes [...
Preprint
Plant root growth is influenced by external factors to adapt to changing environmental conditions. However, the mechanisms by which environmental stresses affect root growth remain elusive. Here we found that DNA double-strand breaks (DSBs) induce the expression of genes for the synthesis of cytokinin hormones and enhance the accumulation of cytoki...
Article
Full-text available
A well-defined set of regulatory pathways control entry into the reproductive phase in flowering plants, but little is known about the mechanistic control of the end-of-flowering despite this being a critical process for optimization of fruit and seed production. Complete fruit removal, or lack of fertile fruit-set, prevents timely inflorescence ar...
Article
Full-text available
The circadian clock coordinates an organism’s growth, development and physiology with environmental factors. One illuminating example is the rhythmic growth of hypocotyls and cotyledons in Arabidopsis thaliana. Such daily oscillations in leaf position are often referred to as sleep movements or nyctinasty. Here, we report that plantlets of the live...
Article
Full-text available
Peptides derived from non-functional precursors play important roles in various developmental processes, but also in (a)biotic stress signaling. Our (phospho)proteome-wide analyses of C-terminally encoded peptide 5 (CEP5)-mediated changes revealed an impact on abiotic stress-related processes. Drought has a dramatic impact on plant growth, developm...
Preprint
Full-text available
Temperature is one of the most impactful environmental factors to which plants adjust their growth and development. While the regulation of temperature signaling has been extensively investigated for the aerial part of plants, much less is known and understood about how roots sense and modulate their growth in response to fluctuating temperatures....
Article
Full-text available
Arctic alpine species follow a mixed clonal-sexual reproductive strategy based on the environmental conditions at flowering. Here, we explored the natural variation for adventitious root formation among genotypes of the alpine perennial Arabis alpina that show differences in flowering habit. We scored the presence of adventitious roots on the hypoc...
Article
Full-text available
Perennials have a complex shoot architecture with axillary meristems organized in zones of differential bud activity and fate. This includes zones of buds maintained dormant for multiple seasons and used as reservoirs for potential growth in case of damage. The shoot of Arabis alpina, a perennial relative of Arabidopsis thaliana, consists of a zone...
Article
Full-text available
Dynamic regulation of the levels of the natural auxin, indole‐3‐acetic acid (IAA), is essential to coordinate most of the physiological and developmental processes and responses to environmental changes. Oxidation of IAA is a major pathway to control auxin concentrations in angiosperms and, along with IAA conjugation, to respond to perturbation of...
Article
Full-text available
Many plant species respond to unfavorable high ambient temperatures by adjusting their vegetative body plan to facilitate cooling. This process is known as thermomorphogenesis and is induced by the phytohormone auxin. Here, we demonstrate that the chromatin-modifying enzyme HISTONE DEACETYLASE 9 (HDA9) mediates thermomorphogenesis but does not inte...
Article
Full-text available
Background: Plants rely on concentration gradients of the native auxin, indole-3-acetic acid (IAA), to modulate plant growth and development. Both metabolic and transport processes participate in the dynamic regulation of IAA homeostasis. Free IAA levels can be reduced by inactivation mechanisms, such as conjugation and degradation. IAA can be con...
Article
Full-text available
PIN-FORMED (PIN) transporters mediate directional, intercellular movement of the phytohormone auxin in land plants. To elucidate the evolutionary origins of this developmentally crucial mechanism, we analysed the single PIN homologue of a simple green alga Klebsormidium flaccidum. KfPIN functions as a plasma membrane-localized auxin exporter in lan...
Article
Full-text available
Mechanisms through which the evolution of gene regulation causes morphological diversity are largely unclear. The tremendous shape variation among plant leaves offers attractive opportunities to address this question. In cruciferous plants, the REDUCED COMPLEXITY (RCO) homeodomain protein evolved via gene duplication and acquired a novel expression...
Article
Mechanical stimuli, such as wind, rain, and touch affect plant development, growth, pest resistance, and ultimately reproductive success. Using water spray to simulate rain, we demonstrate that jasmonic acid (JA) signaling plays a key role in early gene-expression changes, well before it leads to developmental changes in flowering and plant archite...
Article
Full-text available
Epigenetic regulation involves a myriad of mechanisms that regulate the expression of loci without altering the DNA sequence. These different mechanisms primarily result in modifications of the chromatin topology or DNA chemical structure that can be heritable or transient as a dynamic response to environmental cues. The phytohormone auxin plays an...
Preprint
Full-text available
Dynamic regulation of the levels of the natural auxin, indol-3-acetic acid (IAA), is essential to coordinate most of the physiological and developmental processes and responses to environmental changes. Oxidation of IAA is a major pathway to control auxin concentrations in Arabidopsis and, along with IAA conjugation, to respond to perturbation of I...
Article
The organic electronic ion pump (OEIP) provides a unique means for electronically controlled, flow‐free delivery of ions at the cellular scale. In article number 1902189, Eleni Stavrinidou and co‐workers implant a capillary‐based OEIP in a leaf of an intact tobacco plant with no significant wound response and effectively deliver the hormone abscisi...
Article
Full-text available
Electronic control of biological processes with bioelectronic devices holds promise for sophisticated regulation of physiology, for gaining fundamental understanding of biological systems, providing new therapeutic solutions, and digitally mediating adaptations of organisms to external factors. The organic electronic ion pump (OEIP) provides a uniq...
Preprint
Full-text available
Cytokinins are mobile multifunctional plant hormones with roles in development and stress resilience 1,2. Although cytokinin receptors are substantially localised to the endoplasmic reticulum 3-5, the cellular sites of cytokinin perception continue to be debated 1,6,7. Several cytokinin types display bioactivity 8,9 and recently a cell-specific cyt...
Preprint
Full-text available
Background Plants rely on concentration gradients of the native auxin, indole-3-acetic acid (IAA), to modulate plant growth and development. Both metabolic and transport processes participate in the dynamic regulation of IAA homeostasis. Free IAA levels can be reduced by inactivation mechanisms, such as conjugation and degradation. IAA can be conju...
Article
Full-text available
Distribution of auxin within plant tissues is of great importance for developmental plasticity, including root gravitropic growth. Auxin flow is directed by the subcellular polar distribution and dynamic relocalization of auxin transporters such as the PIN‐FORMED (PIN) efflux carriers, which can be influenced by the main natural plant auxin indole‐...
Article
Full-text available
The endodermis is a key cell layer in plant roots that contributes to the controlled uptake of water and mineral nutrients into plants. In order to provide such functionality the endodermal cell wall has specific chemical modifications consisting of lignin bands (Casparian strips) that encircle each cell, and deposition of a waxy-like substance (su...