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. However, it is poorly understood how environmental light and temperature cues interact to effect plant growth. We found that shade combined with warm temperature produces a synergistic hypocotyl growth response that dependent on PHYTOCHROME-INTERACTING FACTOR 7 (PIF7) and auxin. This unique but agriculturally relevant scenario was almost totally independent on PIF4 activity. We show that warm temperature is sufficient to promote PIF7 DNA binding but not transcriptional activation and we demonstrate that additional, unknown factor/s must be working downstream of the phyB-PIF-auxin module. Our findings will improve the predictions of how plants will respond to increased ambient temperatures when grown at high density.

• MeSH
• Arabidopsis * metabolismus   MeSH
• DNA vazebné proteiny metabolismus   MeSH
• faktor VII genetika   metabolismus   MeSH
• fytochrom * metabolismus   MeSH
• hypokotyl metabolismus   MeSH
• kyseliny indoloctové metabolismus   MeSH
• proteiny huseníčku * genetika   metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• světlo MeSH
• transkripční faktory bHLH genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• DNA vazebné proteiny MeSH
• faktor VII MeSH
• fytochrom * MeSH
• kyseliny indoloctové MeSH
• PIF7 protein, Arabidopsis MeSH Prohlížeč
• proteiny huseníčku * MeSH
• transkripční faktory bHLH MeSH

Indole-3-acetic acid (IAA) controls a plethora of developmental processes. Thus, regulation of its concentration is of great relevance for plant performance. Cellular IAA concentration depends on its transport, biosynthesis and the various pathways for IAA inactivation, including oxidation and conjugation. Group II members of the GRETCHEN HAGEN 3 (GH3) gene family code for acyl acid amido synthetases catalysing the conjugation of IAA to amino acids. However, the high degree of functional redundancy among them has hampered thorough analysis of their roles in plant development. In this work, we generated an Arabidopsis gh3.1,2,3,4,5,6,9,17 (gh3oct) mutant to knock out the group II GH3 pathway. The gh3oct plants had an elaborated root architecture, showed an increased tolerance to different osmotic stresses, including an IAA-dependent tolerance to salinity, and were more tolerant to water deficit. Indole-3-acetic acid metabolite quantification in gh3oct plants suggested the existence of additional GH3-like enzymes in IAA metabolism. Moreover, our data suggested that 2-oxindole-3-acetic acid production depends, at least in part, on the GH3 pathway. Targeted stress-hormone analysis further suggested involvement of abscisic acid in the differential response to salinity of gh3oct plants. Taken together, our data provide new insights into the roles of group II GH3s in IAA metabolism and hormone-regulated plant development.

• Klíčová slova
• Arabidopsis, GH3, auxin, drought, salinity, stress tolerance,
• MeSH
• Arabidopsis * metabolismus   MeSH
• hormony metabolismus   MeSH
• kyseliny indoloctové metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• regulátory růstu rostlin metabolismus   MeSH
• salinita MeSH
• voda metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• hormony MeSH
• kyseliny indoloctové MeSH
• regulátory růstu rostlin MeSH
• voda MeSH

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 and cytokinin metabolism during early seedling growth in Theobroma cacao (cacao), we have performed auxin and cytokinin metabolite profiling in hypocotyls and root developmental sections at different times by using ultra-high-performance liquid chromatography-electrospray tandem mass spectrometry (UHPLC-MS/MS). Our work provides quantitative characterization of auxin and cytokinin metabolites throughout early root and hypocotyl development and identifies common and distinctive features of auxin and cytokinin metabolism during cacao seedling development.

• Klíčová slova
• Theobroma cacao, auxin, cytokinin, phytohormone metabolism, root development,
• Publikační typ
• časopisecké články MeSH

Adventitious rooting is a post-embryonic developmental program governed by a multitude of endogenous and environmental cues. Auxin, along with other phytohormones, integrates and translates these cues into precise molecular signatures to provide a coherent developmental output. Auxin signaling guides every step of adventitious root (AR) development from the early event of cell reprogramming and identity transitions until emergence. We have previously shown that auxin signaling controls the early events of AR initiation (ARI) by modulating the homeostasis of the negative regulator jasmonate (JA). Although considerable knowledge has been acquired about the role of auxin and JA in ARI, the genetic components acting downstream of JA signaling and the mechanistic basis controlling the interaction between these two hormones are not well understood. Here we provide evidence that COI1-dependent JA signaling controls the expression of DAO1 and its closely related paralog DAO2. In addition, we show that the dao1-1 loss of function mutant produces more ARs than the wild type, probably due to its deficiency in accumulating JA and its bioactive metabolite JA-Ile. Together, our data indicate that DAO1 controls a sensitive feedback circuit that stabilizes the auxin and JA crosstalk during ARI.

• Klíčová slova
• adventitious roots, auxin, auxin oxidation, jasmonates, organogenesis,
• MeSH
• Arabidopsis genetika   metabolismus   MeSH
• cyklopentany metabolismus   MeSH
• kořeny rostlin genetika   růst a vývoj   MeSH
• kyseliny indoloctové metabolismus   MeSH
• oxidoreduktasy genetika   metabolismus   MeSH
• oxylipiny metabolismus   MeSH
• proteiny huseníčku genetika   metabolismus   MeSH
• signální transdukce MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cyklopentany MeSH
• jasmonic acid MeSH Prohlížeč
• kyseliny indoloctové MeSH
• oxidoreduktasy MeSH
• oxylipiny MeSH
• proteiny huseníčku MeSH

Auxin (indole-3-acetic acid, IAA) plays fundamental roles as a signalling molecule during numerous plant growth and development processes. The formation of local auxin gradients and auxin maxima/minima, which is very important for these processes, is regulated by auxin metabolism (biosynthesis, degradation, and conjugation) as well as transport. When studying auxin metabolism pathways it is crucial to combine data obtained from genetic investigations with the identification and quantification of individual metabolites. Thus, to facilitate efforts to elucidate auxin metabolism and its roles in plants, we have developed a high-throughput method for simultaneously quantifying IAA and its key metabolites in minute samples (<10 mg FW) of Arabidopsis thaliana tissues by in-tip micro solid-phase extraction and fast LC-tandem MS. As a proof of concept, we applied the method to a collection of Arabidopsis mutant lines and identified lines with altered IAA metabolite profiles using multivariate data analysis. Finally, we explored the correlation between IAA metabolite profiles and IAA-related phenotypes. The developed rapid analysis of large numbers of samples (>100 samples d-1) is a valuable tool to screen for novel regulators of auxin metabolism and homeostasis among large collections of genotypes.

• MeSH
• Arabidopsis genetika   metabolismus   MeSH
• chromatografie kapalinová MeSH
• extrakce na pevné fázi MeSH
• kyseliny indoloctové metabolismus   MeSH
• multivariační analýza MeSH
• mutace * MeSH
• rostlinné proteiny analýza   MeSH
• tandemová hmotnostní spektrometrie MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kyseliny indoloctové MeSH
• rostlinné proteiny MeSH