Plant adaptation, growth and development rely on the integration of many environmental and endogenous signals that collectively determine the overall plant phenotypic plasticity. Plant signaling molecules, also known as phytohormones, are fundamental to this process. These molecules act at low concentrations and regulate multiple aspects of plant fitness and development via complex signaling ne...

Phytohormones influence many diverse developmental processes ranging from seed germination to root, shoot, and flower formation. Recently, mutational analysis using the model plant Arabidopsis thaliana has been instrumental in determining the individual components of specific hormone signal transduction pathways. Moreover, epistasis and suppressor studies are beginning to explain how these gene...

The ubiquitin-proteasome system (UPS) plays a role in nearly every aspect of plant biology. The wealth of emerging data demonstrates that regulated protein degradation rivals the well-studied area of transcriptional regulation for importance in cellular regulation. In this Update, we will highlight current research findings that illustrate the contributions of the UPS to phytohormone signaling....

Despite the bewildering ability of higher plants to change their development with respect to the environment, there appear to be only a few hormones that function to organize growth and development. With the recent identification of three plant hormone receptors, the molecular identities of all the major plant receptors are now known. Some plant hormones such as cytokinins, ethylene, and brassi...

Plant growth and development are regulated by a chemically and structurally diverse group of hormones. During the last few decades many advances have been made in understanding the perception and mechanisms of action of these plant hormones. While certain hormone responses are not necessarily related to gene regulation, all these hormones are involved in modulating gene expression by controllin...

Plant hormones play an important role in plant response to abiotic stresses, by both stimulation of defence pathways and regulation of plant growth and development. The key hormone in the response to stresses associated with dehydration is abscisic acid (ABA). Its levels were followed during the response to salinity or drought in two species differing in their stress tolerance – radish and toba...

Plant growth and response to environmental cues are largely governed by phytohormones. The plant hormones ethylene, jasmonic acid, and salicylic acid (SA) play a central role in the regulation of plant immune responses. In addition, other plant hormones, such as auxins, abscisic acid (ABA), cytokinins, gibberellins, and brassinosteroids, that have been thoroughly described to regulate plant dev...

Phytohormones signal and combine to maintain the physiological equilibrium in the plant. Pathogens enhance host susceptibility by modulating the hormonal balance of the plant cell. Unlike other plant hormones, the detailed role of cytokinin in plant immunity remains to be fully elucidated. Here, extensive data mining, including of pathogenicity factors, host regulatory proteins, enzymes of horm...

Above- and belowground plant parts are simultaneously attacked by different pests and pathogens. The host mediates these interactions and physiologically reacts, e.g. with local and systemic alterations of endogenous hormone levels coupled with coordinated transcriptional changes. This in turn affects attractiveness and susceptibility of the plant to subsequent attackers. Here, the model plant ...