Gibberellin-induced parthenocarpy in fruits of a prickly pear mutant.

A parthenocarpic fruit mutant of prickly pear was isolated, revealing the role of GAs in parthenocarpic fruit development which is controlled by the GID-GA20ox/GA2ox genetic system modulating GA biosynthesis/regulation. We explored the intricate dynamics of parthenocarpic fruit development in prickly pear Opuntia ficus-indica (Cactaceae) through the investigation of fruits of the Beer Sheva1 (BS1) a parthenocarpic mutant and its revertant non-parthenocarpic stems. BS1 fruits, characterized by parthenocarpy and enlarged unfertilized ovules, provide a unique model for investigating the regulatory mechanisms underlying fruit development in prickly pear.

Gibberellin-deactivating GA2OX enzymes act as a hub for auxin-gibberellin cross talk in root growth regulation.

Plant bodies are built from immobile cells, making the regulation of cell expansion essential for growth, development, and adaptation. In roots, cell elongation executes the movement of the root tips through the soil. This process is tightly controlled by numerous signaling pathways.

Cytokinin depends on GA biosynthesis and signaling to regulate different aspects of vegetative phase change in Arabidopsis.

The vegetative juvenile-to-adult transition (vegetative phase change) is a critical phase in plant development, the timing of which is controlled by the highly conserved age pathway, comprising the miR156/miR157-SPL module and the downstream miR172-AP2-like module, and is modulated by exogenous and endogenous cues. The phytohormones cytokinin (CK) and gibberellin (GA) have been described to both alter miR172 levels, most probably by regulating SPL activity. In this study, we establish an epistatic relation between CK and GA, in which CK action depends on GA, contrasting with the antagonistic nature described previously for CK-GA crosstalk.

Induced variation in BRASSINOSTEROID INSENSITIVE 1 (BRI1) confers a compact wheat architecture.

Background: The brassinosteroid (BR) plant hormones regulate numerous developmental processes, including those determining stem height, leaf angle, and grain size that have agronomic relevance in cereals. Indeed, barley (Hordeum vulgare) varieties containing uzu alleles that impair BR perception through mutations in the BR receptor BRASSINOSTEROID INSENSITIVE 1 (BRI1) exhibit a semi-dwarf growth habit and more upright leaves suitable for high-density planting. We used forward and reverse genetic approaches to develop novel BRI1 alleles in wheat (Triticum aestivum L.

Brassinolide and BZR1 are up-regulated in a parthenocarpic mutant of prickly pear.

Parthenocarpic fruit development in prickly pear involves up-regulation of the transcription factor BZR1 and increased levels of brassinolide in developing ovules. We explored the complex process of parthenocarpic fruit development in prickly pear Opuntia ficus-indica (Cactaceae) by comparing the fruits of the parthenocarpic Beer Sheva1 (BS1) mutant and revertant non-parthenocarpic fruits. The mutant plants produce flowers with enlarged ovules that develop into degenerated seed-like stony structures.

GIBBERELLIN 3-OXIDASE genes regulate height and grain size in bread wheat.

Plant gibberellin (GA) concentrations are tightly regulated to optimize growth and development. GA 3-oxidases (GA3OX) catalyse a key GA biosynthesis step, converting precursor GAs into bioactive forms. We characterized seven GA3OX homologues in bread wheat (Triticum aestivum L.

Blue or far-red light supplementation induced pre-hardening in the leaves of the Rht12 wheat dwarfing line: hormonal changes and freezing tolerance.

Reduced height (Rht) genes have revolutionised wheat cultivation, but they can compromise freezing tolerance, and only a few alleles are in use. Thus, evaluating the role of other Rht alleles in stress responses is crucial. Far-red supplementation of white light (W+FR) can induce pre-hardening in cereals at 15°C.

A DOF transcriptional repressor-gibberellin feedback loop plays a crucial role in modulating light-independent seed germination.

Plants have evolved several strategies to cope with the ever-changing environment. One example of this is given by seed germination, which must occur when environmental conditions are suitable for plant life. In the model system Arabidopsis thaliana seed germination is induced by light; however, in nature, seeds of several plant species can germinate regardless of this stimulus.

Cell wall integrity modulates HOOKLESS1 and PHYTOCHROME INTERACTING FACTOR4 expression controlling apical hook formation.

Formation of the apical hook in etiolated dicot seedlings results from differential growth in the hypocotyl apex and is tightly controlled by environmental cues and hormones, among which auxin and gibberellins (GAs) play an important role. Cell expansion is tightly regulated by the cell wall, but whether and how feedback from this structure contributes to hook development are still unclear. Here, we show that etiolated seedlings of the Arabidopsis (Arabidopsis thaliana) quasimodo2-1 (qua2) mutant, defective in pectin biosynthesis, display severe defects in apical hook formation and maintenance, accompanied by loss of asymmetric auxin maxima and differential cell expansion.

Stacked mutations in wheat homologues of rice SEMI-DWARF1 confer a novel semi-dwarf phenotype.

Background: Semi-dwarfing alleles are used widely in cereals to confer improved lodging resistance and assimilate partitioning. The most widely deployed semi-dwarfing alleles in rice and barley encode the gibberellin (GA)-biosynthetic enzyme GA 20-OXIDASE2 (GA20OX2). The hexaploid wheat genome carries three homoeologous copies of GA20OX2, and because of functional redundancy, loss-of-function alleles of a single homoeologue would not be selected in wheat breeding programmes.

Strigolactones promote flowering by inducing the miR319-- module in tomato.

Strigolactones are a class of phytohormones with various functions in plant development, stress responses, and in the interaction with (micro)organisms in the rhizosphere. While their effects on vegetative development are well studied, little is known about their role in reproduction. We investigated the effects of genetic and chemical modification of strigolactone levels on the timing and intensity of flowering in tomato ( L.

The dimorphic diaspore model Aethionema arabicum (Brassicaceae): Distinct molecular and morphological control of responses to parental and germination temperatures.

Plants in habitats with unpredictable conditions often have diversified bet-hedging strategies that ensure fitness over a wider range of variable environmental factors. A striking example is the diaspore (seed and fruit) heteromorphism that evolved to maximize species survival in Aethionema arabicum (Brassicaceae) in which external and endogenous triggers allow the production of two distinct diaspores on the same plant. Using this dimorphic diaspore model, we identified contrasting molecular, biophysical, and ecophysiological mechanisms in the germination responses to different temperatures of the mucilaginous seeds (M+ seed morphs), the dispersed indehiscent fruits (IND fruit morphs), and the bare non-mucilaginous M- seeds obtained by pericarp (fruit coat) removal from IND fruits.

BBX21 Integrates Brassinosteroid Biosynthesis and Signaling in the Inhibition of Hypocotyl Growth under Shade.

B-Box-containing zinc finger transcription factors (BBX) are involved in light-mediated growth, affecting processes such as hypocotyl elongation in Arabidopsis thaliana. However, the molecular and hormonal framework that regulates plant growth through BBX proteins is incomplete. Here, we demonstrate that BBX21 inhibits the hypocotyl elongation through the brassinosteroid (BR) pathway.

Hormonal crosstalk controls cell death induced by kinetin in roots of Vicia faba ssp. minor seedlings.

Studies of vitality/mortality of cortex cells, as well as of the concentrations of ethylene (ETH), gibberellins (GAs), indolic compounds/auxins (ICs/AUXs) and cytokinins (CKs), were undertaken to explain the hormonal background of kinetin (Kin)-regulated cell death (RCD), which is induced in the cortex of the apical parts of roots of faba bean (Vicia faba ssp. minor) seedlings. Quantification was carried out with fluorescence microscopy, ETH sensors, spectrophotometry and ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC‒MS/MS).

Domestication has altered the ABA and gibberellin profiles in developing pea seeds.

We showed that wild pea seeds contained a more diverse combination of bioactive GAs and had higher ABA content than domesticated peas. Although the role of abscisic acid (ABA) and gibberellins (GAs) interplay has been extensively studied in Arabidopsis and cereals models, comparatively little is known about the effect of domestication on the level of phytohormones in legume seeds. In legumes, as in other crops, seed dormancy has been largely or entirely removed during domestication.

Contents of endogenous brassinosteroids and the response to drought and/or exogenously applied 24-brassinolide in two different maize leaves.

Exogenously applied brassinosteroids (BRs) improve plant response to drought. However, many important aspects of this process, such as the potential differences caused by different developmental stages of analyzed organs at the beginning of drought, or by BR application before or during drought, remain still unexplored. The same applies for the response of different endogenous BRs belonging to the C, C-and C- structural groups to drought and/or exogenous BRs.

Distinct hormonal and morphological control of dormancy and germination in dimorphic seeds.

Dormancy and heteromorphism are innate seed properties that control germination timing through adaptation to the prevailing environment. The degree of variation in dormancy depth within a seed population differs considerably depending on the genotype and maternal environment. Dormancy is therefore a key trait of annual weeds to time seedling emergence across seasons.

Urea derivative MTU improves stress tolerance and yield in wheat by promoting cyclic electron flow around PSI.

Increasing crop productivity under optimal conditions and mitigating yield losses under stressful conditions is a major challenge in contemporary agriculture. We have recently identified an effective anti-senescence compound (MTU, [1-(2-methoxyethyl)-3-(1,2,3-thiadiazol-5yl)urea]) in studies. Here, we show that MTU delayed both age- and stress-induced senescence of wheat plants ( L.

Phytochromes mediate germination inhibition under red, far-red, and white light in Aethionema arabicum.

The view on the role of light during seed germination stems mainly from studies with Arabidopsis (Arabidopsis thaliana), where light is required to initiate this process. In contrast, white light is a strong inhibitor of germination in other plants, exemplified by accessions of Aethionema arabicum, another member of Brassicaceae. Their seeds respond to light with gene expression changes of key regulators converse to that of Arabidopsis, resulting in opposite hormone regulation and prevention of germination.

CRISPR/Cas9 genome-editing applied to MdPGT1 in apple results in reduced foliar phloridzin without impacting plant growth.

Phloridzin is the most abundant polyphenolic compound in apple (Malus × domestica Borkh.), which results from the action of a key phloretin-specific UDP-2'-O-glucosyltransferase (MdPGT1). Here, we simultaneously assessed the effects of targeting MdPGT1 by conventional transgenesis and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)-mediated genome editing.

A Functional Genomics View of Gibberellin Metabolism in the Cnidarian Symbiont .

Dinoflagellate inhabitants of the reef-building corals exchange nutrients and signals with host cells, which often benefit the growth of both partners. Phytohormones serve as central hubs for signal integration between symbiotic microbes and their hosts, allowing appropriate modulation of plant growth and defense in response to various stresses. However, the presence and function of phytohormones in photosynthetic dinoflagellates and their function in the holobionts remain elusive.

Zaxinone synthase controls arbuscular mycorrhizal colonization level in rice.

The Oryza sativa (rice) carotenoid cleavage dioxygenase OsZAS was described to produce zaxinone, a plant growth-promoting apocarotenoid. A zas mutant line showed reduced arbuscular mycorrhizal (AM) colonization, but the mechanisms underlying this behavior are unknown. Here, we investigated how OsZAS and exogenous zaxinone treatment regulate mycorrhization.

Changes in the concentrations and transcripts for gibberellins and other hormones in a growing leaf and roots of wheat seedlings in response to water restriction.

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 maintain growth at lower GA concentrations compared with shoots, making GA a suitable hormone for mediating this growth redistribution.