@article{8608, abstract = {To adapt to the diverse array of biotic and abiotic cues, plants have evolved sophisticated mechanisms to sense changes in environmental conditions and modulate their growth. Growth-promoting hormones and defence signalling fine tune plant development antagonistically. During host-pathogen interactions, this defence-growth trade-off is mediated by the counteractive effects of the defence hormone salicylic acid (SA) and the growth hormone auxin. Here we revealed an underlying mechanism of SA regulating auxin signalling by constraining the plasma membrane dynamics of PIN2 auxin efflux transporter in Arabidopsis thaliana roots. The lateral diffusion of PIN2 proteins is constrained by SA signalling, during which PIN2 proteins are condensed into hyperclusters depending on REM1.2-mediated nanodomain compartmentalisation. Furthermore, membrane nanodomain compartmentalisation by SA or Remorin (REM) assembly significantly suppressed clathrin-mediated endocytosis. Consequently, SA-induced heterogeneous surface condensation disrupted asymmetric auxin distribution and the resultant gravitropic response. Our results demonstrated a defence-growth trade-off mechanism by which SA signalling crosstalked with auxin transport by concentrating membrane-resident PIN2 into heterogeneous compartments.}, author = {Ke, M and Ma, Z and Wang, D and Sun, Y and Wen, C and Huang, D and Chen, Z and Yang, L and Tan, Shutang and Li, R and Friml, Jiří and Miao, Y and Chen, X}, issn = {1469-8137}, journal = {New Phytologist}, number = {2}, pages = {963--978}, publisher = {Wiley}, title = {{Salicylic acid regulates PIN2 auxin transporter hyper-clustering and root gravitropic growth via Remorin-dependent lipid nanodomain organization in Arabidopsis thaliana}}, doi = {10.1111/nph.16915}, volume = {229}, year = {2021}, } @article{9288, abstract = {• The phenylpropanoid pathway serves a central role in plant metabolism, providing numerous compounds involved in diverse physiological processes. Most carbon entering the pathway is incorporated into lignin. Although several phenylpropanoid pathway mutants show seedling growth arrest, the role for lignin in seedling growth and development is unexplored. • We use complementary pharmacological and genetic approaches to block CINNAMATE‐4‐HYDROXYLASE (C4H) functionality in Arabidopsis seedlings and a set of molecular and biochemical techniques to investigate the underlying phenotypes. • Blocking C4H resulted in reduced lateral rooting and increased adventitious rooting apically in the hypocotyl. These phenotypes coincided with an inhibition in auxin transport. The upstream accumulation in cis‐cinnamic acid was found to likely cause polar auxin transport inhibition. Conversely, a downstream depletion in lignin perturbed phloem‐mediated auxin transport. Restoring lignin deposition effectively reestablished phloem transport and, accordingly, auxin homeostasis. • Our results show that the accumulation of bioactive intermediates and depletion in lignin jointly cause the aberrant phenotypes upon blocking C4H, and demonstrate that proper deposition of lignin is essential for the establishment of auxin distribution in seedlings. Our data position the phenylpropanoid pathway and lignin in a new physiological framework, consolidating their importance in plant growth and development.}, author = {El Houari, I and Van Beirs, C and Arents, HE and Han, Huibin and Chanoca, A and Opdenacker, D and Pollier, J and Storme, V and Steenackers, W and Quareshy, M and Napier, R and Beeckman, T and Friml, Jiří and De Rybel, B and Boerjan, W and Vanholme, B}, issn = {1469-8137}, journal = {New Phytologist}, number = {6}, pages = {2275--2291}, publisher = {Wiley}, title = {{Seedling developmental defects upon blocking CINNAMATE-4-HYDROXYLASE are caused by perturbations in auxin transport}}, doi = {10.1111/nph.17349}, volume = {230}, year = {2021}, } @article{9656, abstract = {Tropisms, growth responses to environmental stimuli such as light or gravity, are spectacular examples of adaptive plant development. The plant hormone auxin serves as a major coordinative signal. The PIN auxin exporters, through their dynamic polar subcellular localizations, redirect auxin fluxes in response to environmental stimuli and the resulting auxin gradients across organs underly differential cell elongation and bending. In this review, we discuss recent advances concerning regulations of PIN polarity during tropisms, focusing on PIN phosphorylation and trafficking. We also cover how environmental cues regulate PIN actions during tropisms, and a crucial role of auxin feedback on PIN polarity during bending termination. Finally, the interactions between different tropisms are reviewed to understand plant adaptive growth in the natural environment.}, author = {Han, Huibin and Adamowski, Maciek and Qi, Linlin and Alotaibi, SS and Friml, Jiří}, issn = {1469-8137}, journal = {New Phytologist}, number = {2}, pages = {510--522}, publisher = {Wiley}, title = {{PIN-mediated polar auxin transport regulations in plant tropic responses}}, doi = {10.1111/nph.17617}, volume = {232}, year = {2021}, } @article{6997, author = {Zhang, Yuzhou and Friml, Jiří}, issn = {1469-8137}, journal = {New Phytologist}, number = {3}, pages = {1049--1052}, publisher = {Wiley}, title = {{Auxin guides roots to avoid obstacles during gravitropic growth}}, doi = {10.1111/nph.16203}, volume = {225}, year = {2020}, } @article{7500, abstract = {Plant survival depends on vascular tissues, which originate in a self‐organizing manner as strands of cells co‐directionally transporting the plant hormone auxin. The latter phenomenon (also known as auxin canalization) is classically hypothesized to be regulated by auxin itself via the effect of this hormone on the polarity of its own intercellular transport. Correlative observations supported this concept, but molecular insights remain limited. In the current study, we established an experimental system based on the model Arabidopsis thaliana, which exhibits auxin transport channels and formation of vasculature strands in response to local auxin application. Our methodology permits the genetic analysis of auxin canalization under controllable experimental conditions. By utilizing this opportunity, we confirmed the dependence of auxin canalization on a PIN‐dependent auxin transport and nuclear, TIR1/AFB‐mediated auxin signaling. We also show that leaf venation and auxin‐mediated PIN repolarization in the root require TIR1/AFB signaling. Further studies based on this experimental system are likely to yield better understanding of the mechanisms underlying auxin transport polarization in other developmental contexts.}, author = {Mazur, E and Kulik, Ivan and Hajny, Jakub and Friml, Jiří}, issn = {1469-8137}, journal = {New Phytologist}, number = {5}, pages = {1375--1383}, publisher = {Wiley}, title = {{Auxin canalization and vascular tissue formation by TIR1/AFB-mediated auxin signaling in arabidopsis}}, doi = {10.1111/nph.16446}, volume = {226}, year = {2020}, } @article{6504, abstract = {Root gravitropism is one of the most important processes allowing plant adaptation to the land environment. Auxin plays a central role in mediating root gravitropism, but how auxin contributes to gravitational perception and the subsequent response is still unclear. Here, we showed that the local auxin maximum/gradient within the root apex, which is generated by the PIN directional auxin transporters, regulates the expression of three key starch granule synthesis genes, SS4, PGM and ADG1, which in turn influence the accumulation of starch granules that serve as a statolith perceiving gravity. Moreover, using the cvxIAA‐ccvTIR1 system, we also showed that TIR1‐mediated auxin signaling is required for starch granule formation and gravitropic response within root tips. In addition, axr3 mutants showed reduced auxin‐mediated starch granule accumulation and disruption of gravitropism within the root apex. Our results indicate that auxin‐mediated statolith production relies on the TIR1/AFB‐AXR3‐mediated auxin signaling pathway. In summary, we propose a dual role for auxin in gravitropism: the regulation of both gravity perception and response.}, author = {Zhang, Yuzhou and He, P and Ma, X and Yang, Z and Pang, C and Yu, J and Wang, G and Friml, Jiří and Xiao, G}, issn = {1469-8137}, journal = {New Phytologist}, number = {2}, pages = {761--774}, publisher = {Wiley}, title = {{Auxin-mediated statolith production for root gravitropism}}, doi = {10.1111/nph.15932}, volume = {224}, year = {2019}, }