@article{12144, abstract = {The phytohormone auxin is the major coordinative signal in plant development1, mediating transcriptional reprogramming by a well-established canonical signalling pathway. TRANSPORT INHIBITOR RESPONSE 1 (TIR1)/AUXIN-SIGNALING F-BOX (AFB) auxin receptors are F-box subunits of ubiquitin ligase complexes. In response to auxin, they associate with Aux/IAA transcriptional repressors and target them for degradation via ubiquitination2,3. Here we identify adenylate cyclase (AC) activity as an additional function of TIR1/AFB receptors across land plants. Auxin, together with Aux/IAAs, stimulates cAMP production. Three separate mutations in the AC motif of the TIR1 C-terminal region, all of which abolish the AC activity, each render TIR1 ineffective in mediating gravitropism and sustained auxin-induced root growth inhibition, and also affect auxin-induced transcriptional regulation. These results highlight the importance of TIR1/AFB AC activity in canonical auxin signalling. They also identify a unique phytohormone receptor cassette combining F-box and AC motifs, and the role of cAMP as a second messenger in plants.}, author = {Qi, Linlin and Kwiatkowski, Mateusz and Chen, Huihuang and Hörmayer, Lukas and Sinclair, Scott A and Zou, Minxia and del Genio, Charo I. and Kubeš, Martin F. and Napier, Richard and Jaworski, Krzysztof and Friml, Jiří}, issn = {1476-4687}, journal = {Nature}, number = {7934}, pages = {133--138}, publisher = {Springer Nature}, title = {{Adenylate cyclase activity of TIR1/AFB auxin receptors in plants}}, doi = {10.1038/s41586-022-05369-7}, volume = {611}, year = {2022}, } @article{7417, abstract = {Previously, we reported that the allelic de-etiolated by zinc (dez) and trichome birefringence (tbr) mutants exhibit photomorphogenic development in the dark, which is enhanced by high Zn. TRICHOME BIREFRINGENCE-LIKE proteins had been implicated in transferring acetyl groups to various hemicelluloses. Pectin O-acetylation levels were lower in dark-grown dez seedlings than in the wild type. We observed Zn-enhanced photomorphogenesis in the dark also in the reduced wall acetylation 2 (rwa2-3) mutant, which exhibits lowered O-acetylation levels of cell wall macromolecules including pectins and xyloglucans, supporting a role for cell wall macromolecule O-acetylation in the photomorphogenic phenotypes of rwa2-3 and dez. Application of very short oligogalacturonides (vsOGs) restored skotomorphogenesis in dark-grown dez and rwa2-3. Here we demonstrate that in dez, O-acetylation of non-pectin cell wall components, notably of xyloglucan, is enhanced. Our results highlight the complexity of cell wall homeostasis and indicate against an influence of xyloglucan O-acetylation on light-dependent seedling development.}, author = {Sinclair, Scott A and Gille, S. and Pauly, M. and Krämer, U.}, issn = {1559-2324}, journal = {Plant Signaling & Behavior}, number = {1}, publisher = {Informa UK Limited}, title = {{Regulation of acetylation of plant cell wall components is complex and responds to external stimuli}}, doi = {10.1080/15592324.2019.1687185}, volume = {15}, year = {2020}, } @article{7416, abstract = {Earlier, we demonstrated that transcript levels of METAL TOLERANCE PROTEIN2 (MTP2) and of HEAVY METAL ATPase2 (HMA2) increase strongly in roots of Arabidopsis upon prolonged zinc (Zn) deficiency and respond to shoot physiological Zn status, and not to the local Zn status in roots. This provided evidence for shoot-to-root communication in the acclimation of plants to Zn deficiency. Zn-deficient soils limit both the yield and quality of agricultural crops and can result in clinically relevant nutritional Zn deficiency in human populations. Implementing Zn deficiency during cultivation of the model plant Arabidopsis thaliana on agar-solidified media is difficult because trace element contaminations are present in almost all commercially available agars. Here, we demonstrate root morphological acclimations to Zn deficiency on agar-solidified medium following the effective removal of contaminants. These advancements allow reproducible phenotyping toward understanding fundamental plant responses to deficiencies of Zn and other essential trace elements.}, author = {Sinclair, Scott A and Krämer, U.}, issn = {1559-2324}, journal = {Plant Signaling & Behavior}, number = {1}, publisher = {Taylor & Francis}, title = {{Generation of effective zinc-deficient agar-solidified media allows identification of root morphology changes in response to zinc limitation}}, doi = {10.1080/15592324.2019.1687175}, volume = {15}, year = {2020}, } @article{7143, abstract = {Roots grow downwards parallel to the gravity vector, to anchor a plant in soil and acquire water and nutrients, using a gravitropic mechanism dependent on the asymmetric distribution of the phytohormone auxin. Recently, Chang et al. demonstrate that asymmetric distribution of another phytohormone, cytokinin, directs root growth towards higher water content.}, author = {Sinclair, Scott A and Friml, Jiří}, issn = {1748-7838}, journal = {Cell Research}, pages = {965--966}, publisher = {Springer Nature}, title = {{Defying gravity: a plant's quest for moisture}}, doi = {10.1038/s41422-019-0254-4}, volume = {29}, year = {2019}, }