During the last century, two key hypotheses have been proposed to explain apical dominance in plants: auxin promotes the production of a second messenger that moves up into buds to repress their outgrowth, and auxin saturation in the stem inhibits auxin transport from buds, thereby inhibiting bud outgrowth. The recent discovery of strigolactone as the novel shoot-branching inhibitor allowed us ...

Auxin is an essential regulator of virtually all aspects of plant growth and development and components of the auxin signaling pathway are conserved among land plants. Yet, a remarkable degree of natural variation in physiological and transcriptional auxin responses has been described among Arabidopsis thaliana accessions. Such variations might be caused by divergence in promoter or coding sequ...

BACKGROUND In plants, the phytohormone auxin is a crucial regulator sustaining growth and development. At the cellular level, auxin is interpreted differentially in a tissue- and dose-dependent manner. Mechanisms of auxin signalling are partially unknown and the contribution of the AUXIN BINDING PROTEIN 1 (ABP1) as an auxin receptor is still a matter of debate. METHODOLOGY/PRINCIPAL FINDINGS ...

The phytohormone auxin is one of the most important signaling molecules that undergo accumulation or depletion in a temporal or spatial manner due to wide arrays of changes in developmental or stress programs. Proper distribution, maintenance and homeostasis of auxin molecules across the plant systems are one of the most important phenomena required for proper growth and development of plant. T...

AUXIN RESPONSE FACTOR7 (ARF7) is one of five ARF transcriptional activators in Arabidopsis thaliana that is proposed to regulate auxin-responsive expression of genes containing TGTCTC auxin response elements in their promoters. An Arabidopsis mutant (nonphototropic hypocotyl4-1 [nph4-1]) that is a null for ARF7 showed strongly reduced expression of integrated auxin-responsive reporter genes and...

The transition from dormancy to germination in seeds is a key physiological process during the lifecycle of plants. Abscisic acid (ABA) is the sole plant hormone known to maintain seed dormancy; it acts through a gene expression network involving the transcription factor ABSCISIC ACID INSENSITIVE 3 (ABI3). However, whether other phytohormone pathways function in the maintenance of seed dormancy...

Background The phytohormone auxin is critical for plant growth and orchestrates many developmental processes. Scope This review considers the complex array of mechanisms plants use to control auxin levels, the movement of auxin through the plant, the emerging view of auxin-signalling mechanisms, and several interactions between auxin and other phytohormones. Though many natural and synthetic co...

ABP1 and TIR1/AFBs are known as auxin receptors. ABP1 is linked to auxin responses several of which are faster than 10 min. TIR1 regulates auxin-induced transcription of early auxin genes also within minutes. We use transcription of such TIR1-dependent genes as indicator of TIR1 activity to show the rapid regulation of TIR1 by exogenous auxin. To this end, we used quantification of transcriptio...

Establishment of the embryonic axis foreshadows the main body axis of adults both in plants and in animals, but underlying mechanisms are considered distinct. Plants utilize directional, cell-to-cell transport of the growth hormone auxin to generate an asymmetric auxin response that specifies the embryonic apical-basal axis. The auxin flow directionality depends on the polarized subcellular loc...

The plant hormone and signaling molecule auxin is a key player during pattern formation, organogenesis, and various physiological processes. Recent discoveries in auxin biology point toward an auxin pathway with a higher complexity than previously anticipated. This prompted us to review this constantly growing field and to put these novel and exciting findings into a broader developmental and e...