@article{14826,
abstract = {The plant-signaling molecule auxin triggers fast and slow cellular responses across land plants and algae. The nuclear auxin pathway mediates gene expression and controls growth and development in land plants, but this pathway is absent from algal sister groups. Several components of rapid responses have been identified in Arabidopsis, but it is unknown if these are part of a conserved mechanism. We recently identified a fast, proteome-wide phosphorylation response to auxin. Here, we show that this response occurs across 5 land plant and algal species and converges on a core group of shared targets. We found conserved rapid physiological responses to auxin in the same species and identified rapidly accelerated fibrosarcoma (RAF)-like protein kinases as central mediators of auxin-triggered phosphorylation across species. Genetic analysis connects this kinase to both auxin-triggered protein phosphorylation and rapid cellular response, thus identifying an ancient mechanism for fast auxin responses in the green lineage.},
author = {Kuhn, Andre and Roosjen, Mark and Mutte, Sumanth and Dubey, Shiv Mani and Carrillo Carrasco, Vanessa Polet and Boeren, Sjef and Monzer, Aline and Koehorst, Jasper and Kohchi, Takayuki and Nishihama, Ryuichi and Fendrych, Matyas and Sprakel, Joris and Friml, Jiří and Weijers, Dolf},
issn = {1097-4172},
journal = {Cell},
keywords = {General Biochemistry, Genetics and Molecular Biology},
number = {1},
pages = {130--148.e17},
publisher = {Elsevier},
title = {{RAF-like protein kinases mediate a deeply conserved, rapid auxin response}},
doi = {10.1016/j.cell.2023.11.021},
volume = {187},
year = {2024},
}
@article{15033,
abstract = {The GNOM (GN) Guanine nucleotide Exchange Factor for ARF small GTPases (ARF-GEF) is among the best studied trafficking regulators in plants, playing crucial and unique developmental roles in patterning and polarity. The current models place GN at the Golgi apparatus (GA), where it mediates secretion/recycling, and at the plasma membrane (PM) presumably contributing to clathrin-mediated endocytosis (CME). The mechanistic basis of the developmental function of GN, distinct from the other ARF-GEFs including its closest homologue GNOM-LIKE1 (GNL1), remains elusive. Insights from this study largely extend the current notions of GN function. We show that GN, but not GNL1, localizes to the cell periphery at long-lived structures distinct from clathrin-coated pits, while CME and secretion proceed normally in gn knockouts. The functional GN mutant variant GNfewerroots, absent from the GA, suggests that the cell periphery is the major site of GN action responsible for its developmental function. Following inhibition by Brefeldin A, GN, but not GNL1, relocates to the PM likely on exocytic vesicles, suggesting selective molecular associations en route to the cell periphery. A study of GN-GNL1 chimeric ARF-GEFs indicates that all GN domains contribute to the specific GN function in a partially redundant manner. Together, this study offers significant steps toward the elucidation of the mechanism underlying unique cellular and development functions of GNOM.},
author = {Adamowski, Maciek and Matijevic, Ivana and Friml, Jiří},
issn = {2050-084X},
journal = {eLife},
keywords = {General Immunology and Microbiology, General Biochemistry, Genetics and Molecular Biology, General Medicine, General Neuroscience},
publisher = {eLife Sciences Publications},
title = {{Developmental patterning function of GNOM ARF-GEF mediated from the cell periphery}},
doi = {10.7554/elife.68993},
volume = {13},
year = {2024},
}
@article{14251,
abstract = {The phytohormone auxin and its directional transport through tissues play a fundamental role in development of higher plants. This polar auxin transport predominantly relies on PIN-FORMED (PIN) auxin exporters. Hence, PIN polarization is crucial for development, but its evolution during the rise of morphological complexity in land plants remains unclear. Here, we performed a cross-species investigation by observing the trafficking and localization of endogenous and exogenous PINs in two bryophytes, Physcomitrium patens and Marchantia polymorpha, and in the flowering plant Arabidopsis thaliana. We confirmed that the GFP fusion did not compromise the auxin export function of all examined PINs by using radioactive auxin export assay and by observing the phenotypic changes in transgenic bryophytes. Endogenous PINs polarize to filamentous apices, while exogenous Arabidopsis PINs distribute symmetrically on the membrane in both bryophytes. In Arabidopsis root epidermis, bryophytic PINs show no defined polarity. Pharmacological interference revealed a strong cytoskeleton dependence of bryophytic but not Arabidopsis PIN polarization. The divergence of PIN polarization and trafficking is also observed within the bryophyte clade and between tissues of individual species. These results collectively reveal a divergence of PIN trafficking and polarity mechanisms throughout land plant evolution and a co-evolution of PIN sequence-based and cell-based polarity mechanisms.},
author = {Tang, Han and Lu, KJ and Zhang, Y and Cheng, YL and Tu, SL and Friml, Jiří},
issn = {2590-3462},
journal = {Plant Communications},
number = {1},
publisher = {Elsevier},
title = {{Divergence of trafficking and polarization mechanisms for PIN auxin transporters during land plant evolution}},
doi = {10.1016/j.xplc.2023.100669},
volume = {5},
year = {2024},
}
@article{13212,
abstract = {Auxin is the major plant hormone regulating growth and development (Friml, 2022). Forward genetic approaches in the model plant Arabidopsis thaliana have identified major components of auxin signalling and established the canonical mechanism mediating transcriptional and thus developmental reprogramming. In this textbook view, TRANSPORT INHIBITOR RESPONSE 1 (TIR1)/AUXIN-SIGNALING F-BOX (AFBs) are auxin receptors, which act as F-box subunits determining the substrate specificity of the Skp1-Cullin1-F box protein (SCF) type E3 ubiquitin ligase complex. Auxin acts as a “molecular glue” increasing the affinity between TIR1/AFBs and the Aux/IAA repressors. Subsequently, Aux/IAAs are ubiquitinated and degraded, thus releasing auxin transcription factors from their repression making them free to mediate transcription of auxin response genes (Yu et al., 2022). Nonetheless, accumulating evidence suggests existence of rapid, non-transcriptional responses downstream of TIR1/AFBs such as auxin-induced cytosolic calcium (Ca2+) transients, plasma membrane depolarization and apoplast alkalinisation, all converging on the process of root growth inhibition and root gravitropism (Li et al., 2022). Particularly, these rapid responses are mostly contributed by predominantly cytosolic AFB1, while the long-term growth responses are mediated by mainly nuclear TIR1 and AFB2-AFB5 (Li et al., 2021; Prigge et al., 2020; Serre et al., 2021). How AFB1 conducts auxin-triggered rapid responses and how it is different from TIR1 and AFB2-AFB5 remains elusive. Here, we compare the roles of TIR1 and AFB1 in transcriptional and rapid responses by modulating their subcellular localization in Arabidopsis and by testing their ability to mediate transcriptional responses when part of the minimal auxin circuit reconstituted in yeast.},
author = {Chen, Huihuang and Li, Lanxin and Zou, Minxia and Qi, Linlin and Friml, Jiří},
issn = {1674-2052},
journal = {Molecular Plant},
number = {7},
pages = {1117--1119},
publisher = {Elsevier },
title = {{Distinct functions of TIR1 and AFB1 receptors in auxin signalling.}},
doi = {10.1016/j.molp.2023.06.007},
volume = {16},
year = {2023},
}
@article{10717,
abstract = {Much of what we know about the role of auxin in plant development derives from exogenous manipulations of auxin distribution and signaling, using inhibitors, auxins and auxin analogs. In this context, synthetic auxin analogs, such as 1-Naphtalene Acetic Acid (1-NAA), are often favored over the endogenous auxin indole-3-acetic acid (IAA), in part due to their higher stability. While such auxin analogs have proven to be instrumental to reveal the various faces of auxin, they display in some cases distinct bioactivities compared to IAA. Here, we focused on the effect of auxin analogs on the accumulation of PIN proteins in Brefeldin A-sensitive endosomal aggregations (BFA bodies), and the correlation with the ability to elicit Ca 2+ responses. For a set of commonly used auxin analogs, we evaluated if auxin-analog induced Ca 2+ signaling inhibits PIN accumulation. Not all auxin analogs elicited a Ca 2+ response, and their differential ability to elicit Ca 2+ responses correlated partially with their ability to inhibit BFA-body formation. However, in tir1/afb and cngc14, 1-NAA-induced Ca 2+ signaling was strongly impaired, yet 1-NAA still could inhibit PIN accumulation in BFA bodies. This demonstrates that TIR1/AFB-CNGC14-dependent Ca 2+ signaling does not inhibit BFA body formation in Arabidopsis roots.},
author = {Wang, R and Himschoot, E and Grenzi, M and Chen, J and Safi, A and Krebs, M and Schumacher, K and Nowack, MK and Moeder, W and Yoshioka, K and Van Damme, D and De Smet, I and Geelen, D and Beeckman, T and Friml, Jiří and Costa, A and Vanneste, S},
issn = {1460-2431},
journal = {Journal of Experimental Botany},
number = {8},
publisher = {Oxford Academic},
title = {{Auxin analog-induced Ca2+ signaling is independent of inhibition of endosomal aggregation in Arabidopsis roots}},
doi = {10.1093/jxb/erac019},
volume = {73},
year = {2022},
}
@phdthesis{11626,
abstract = {Plant growth and development is well known to be both, flexible and dynamic. The high capacity for post-embryonic organ formation and tissue regeneration requires tightly regulated intercellular communication and coordinated tissue polarization. One of the most important drivers for patterning and polarity in plant development is the phytohormone auxin. Auxin has the unique characteristic to establish polarized channels for its own active directional cell to cell transport. This fascinating phenomenon is called auxin canalization. Those auxin transport channels are characterized by the expression and polar, subcellular localization of PIN auxin efflux carriers. PIN proteins have the ability to dynamically change their localization and auxin itself can affect this by interfering with trafficking. Most of the underlying molecular mechanisms of canalization still remain enigmatic. What is known so far is that canonical auxin signaling is indispensable but also other non-canonical signaling components are thought to play a role. In order to shed light into the mysteries auf auxin canalization this study revisits the branches of auxin signaling in detail. Further a new auxin analogue, PISA, is developed which triggers auxin-like responses but does not directly activate canonical transcriptional auxin signaling. We revisit the direct auxin effect on PIN trafficking where we found that, contradictory to previous observations, auxin is very specifically promoting endocytosis of PIN2 but has no overall effect on endocytosis. Further, we evaluate which cellular processes related to PIN subcellular dynamics are involved in the establishment of auxin conducting channels and the formation of vascular tissue. We are re-evaluating the function of AUXIN BINDING PROTEIN 1 (ABP1) and provide a comprehensive picture about its developmental phneotypes and involvement in auxin signaling and canalization. Lastly, we are focusing on the crosstalk between the hormone strigolactone (SL) and auxin and found that SL is interfering with essentially all processes involved in auxin canalization in a non-transcriptional manner. Lastly we identify a new way of SL perception and signaling which is emanating from mitochondria, is independent of canonical SL signaling and is modulating primary root growth.},
author = {Gallei, Michelle C},
isbn = {978-3-99078-019-0},
issn = {2663-337X},
pages = {248},
publisher = {Institute of Science and Technology Austria},
title = {{Auxin and strigolactone non-canonical signaling regulating development in Arabidopsis thaliana}},
doi = {10.15479/at:ista:11626},
year = {2022},
}
@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{12291,
abstract = {The phytohormone auxin triggers transcriptional reprogramming through a well-characterized perception machinery in the nucleus. By contrast, mechanisms that underlie fast effects of auxin, such as the regulation of ion fluxes, rapid phosphorylation of proteins or auxin feedback on its transport, remain unclear1,2,3. Whether auxin-binding protein 1 (ABP1) is an auxin receptor has been a source of debate for decades1,4. Here we show that a fraction of Arabidopsis thaliana ABP1 is secreted and binds auxin specifically at an acidic pH that is typical of the apoplast. ABP1 and its plasma-membrane-localized partner, transmembrane kinase 1 (TMK1), are required for the auxin-induced ultrafast global phospho-response and for downstream processes that include the activation of H+-ATPase and accelerated cytoplasmic streaming. abp1 and tmk mutants cannot establish auxin-transporting channels and show defective auxin-induced vasculature formation and regeneration. An ABP1(M2X) variant that lacks the capacity to bind auxin is unable to complement these defects in abp1 mutants. These data indicate that ABP1 is the auxin receptor for TMK1-based cell-surface signalling, which mediates the global phospho-response and auxin canalization.},
author = {Friml, Jiří and Gallei, Michelle C and Gelová, Zuzana and Johnson, Alexander J and Mazur, Ewa and Monzer, Aline and Rodriguez Solovey, Lesia and Roosjen, Mark and Verstraeten, Inge and Živanović, Branka D. and Zou, Minxia and Fiedler, Lukas and Giannini, Caterina and Grones, Peter and Hrtyan, Mónika and Kaufmann, Walter and Kuhn, Andre and Narasimhan, Madhumitha and Randuch, Marek and Rýdza, Nikola and Takahashi, Koji and Tan, Shutang and Teplova, Anastasiia and Kinoshita, Toshinori and Weijers, Dolf and Rakusová, Hana},
issn = {1476-4687},
journal = {Nature},
number = {7927},
pages = {575--581},
publisher = {Springer Nature},
title = {{ABP1–TMK auxin perception for global phosphorylation and auxin canalization}},
doi = {10.1038/s41586-022-05187-x},
volume = {609},
year = {2022},
}
@article{8582,
abstract = {Cell and tissue polarization is fundamental for plant growth and morphogenesis. The polar, cellular localization of Arabidopsis PIN‐FORMED (PIN) proteins is crucial for their function in directional auxin transport. The clustering of PIN polar cargoes within the plasma membrane has been proposed to be important for the maintenance of their polar distribution. However, the more detailed features of PIN clusters and the cellular requirements of cargo clustering remain unclear.
Here, we characterized PIN clusters in detail by means of multiple advanced microscopy and quantification methods, such as 3D quantitative imaging or freeze‐fracture replica labeling. The size and aggregation types of PIN clusters were determined by electron microscopy at the nanometer level at different polar domains and at different developmental stages, revealing a strong preference for clustering at the polar domains.
Pharmacological and genetic studies revealed that PIN clusters depend on phosphoinositol pathways, cytoskeletal structures and specific cell‐wall components as well as connections between the cell wall and the plasma membrane.
This study identifies the role of different cellular processes and structures in polar cargo clustering and provides initial mechanistic insight into the maintenance of polarity in plants and other systems.},
author = {Li, Hongjiang and von Wangenheim, Daniel and Zhang, Xixi and Tan, Shutang and Darwish-Miranda, Nasser and Naramoto, Satoshi and Wabnik, Krzysztof T and de Rycke, Riet and Kaufmann, Walter and Gütl, Daniel J and Tejos, Ricardo and Grones, Peter and Ke, Meiyu and Chen, Xu and Dettmer, Jan and Friml, Jiří},
issn = {14698137},
journal = {New Phytologist},
number = {1},
pages = {351--369},
publisher = {Wiley},
title = {{Cellular requirements for PIN polar cargo clustering in Arabidopsis thaliana}},
doi = {10.1111/nph.16887},
volume = {229},
year = {2021},
}
@article{8931,
abstract = {Auxin is a major plant growth regulator, but current models on auxin perception and signaling cannot explain the whole plethora of auxin effects, in particular those associated with rapid responses. A possible candidate for a component of additional auxin perception mechanisms is the AUXIN BINDING PROTEIN 1 (ABP1), whose function in planta remains unclear.
Here we combined expression analysis with gain- and loss-of-function approaches to analyze the role of ABP1 in plant development. ABP1 shows a broad expression largely overlapping with, but not regulated by, transcriptional auxin response activity. Furthermore, ABP1 activity is not essential for the transcriptional auxin signaling. Genetic in planta analysis revealed that abp1 loss-of-function mutants show largely normal development with minor defects in bolting. On the other hand, ABP1 gain-of-function alleles show a broad range of growth and developmental defects, including root and hypocotyl growth and bending, lateral root and leaf development, bolting, as well as response to heat stress. At the cellular level, ABP1 gain-of-function leads to impaired auxin effect on PIN polar distribution and affects BFA-sensitive PIN intracellular aggregation.
The gain-of-function analysis suggests a broad, but still mechanistically unclear involvement of ABP1 in plant development, possibly masked in abp1 loss-of-function mutants by a functional redundancy.},
author = {Gelová, Zuzana and Gallei, Michelle C and Pernisová, Markéta and Brunoud, Géraldine and Zhang, Xixi and Glanc, Matous and Li, Lanxin and Michalko, Jaroslav and Pavlovicova, Zlata and Verstraeten, Inge and Han, Huibin and Hajny, Jakub and Hauschild, Robert and Čovanová, Milada and Zwiewka, Marta and Hörmayer, Lukas and Fendrych, Matyas and Xu, Tongda and Vernoux, Teva and Friml, Jiří},
issn = {0168-9452},
journal = {Plant Science},
keywords = {Agronomy and Crop Science, Plant Science, Genetics, General Medicine},
publisher = {Elsevier},
title = {{Developmental roles of auxin binding protein 1 in Arabidopsis thaliana}},
doi = {10.1016/j.plantsci.2020.110750},
volume = {303},
year = {2021},
}
@article{8992,
abstract = {The phytohormone auxin plays a central role in shaping plant growth and development. With decades of genetic and biochemical studies, numerous core molecular components and their networks, underlying auxin biosynthesis, transport, and signaling, have been identified. Notably, protein phosphorylation, catalyzed by kinases and oppositely hydrolyzed by phosphatases, has been emerging to be a crucial type of post-translational modification, regulating physiological and developmental auxin output at all levels. In this review, we comprehensively discuss earlier and recent advances in our understanding of genetics, biochemistry, and cell biology of the kinases and phosphatases participating in auxin action. We provide insights into the mechanisms by which reversible protein phosphorylation defines developmental auxin responses, discuss current challenges, and provide our perspectives on future directions involving the integration of the control of protein phosphorylation into the molecular auxin network.},
author = {Tan, Shutang and Luschnig, Christian and Friml, Jiří},
issn = {17529867},
journal = {Molecular Plant},
number = {1},
pages = {151--165},
publisher = {Elsevier},
title = {{Pho-view of auxin: Reversible protein phosphorylation in auxin biosynthesis, transport and signaling}},
doi = {10.1016/j.molp.2020.11.004},
volume = {14},
year = {2021},
}
@article{8993,
abstract = {N-1-naphthylphthalamic acid (NPA) is a key inhibitor of directional (polar) transport of the hormone auxin in plants. For decades, it has been a pivotal tool in elucidating the unique polar auxin transport-based processes underlying plant growth and development. Its exact mode of action has long been sought after and is still being debated, with prevailing mechanistic schemes describing only indirect connections between NPA and the main transporters responsible for directional transport, namely PIN auxin exporters. Here we present data supporting a model in which NPA associates with PINs in a more direct manner than hitherto postulated. We show that NPA inhibits PIN activity in a heterologous oocyte system and that expression of NPA-sensitive PINs in plant, yeast, and oocyte membranes leads to specific saturable NPA binding. We thus propose that PINs are a bona fide NPA target. This offers a straightforward molecular basis for NPA inhibition of PIN-dependent auxin transport and a logical parsimonious explanation for the known physiological effects of NPA on plant growth, as well as an alternative hypothesis to interpret past and future results. We also introduce PIN dimerization and describe an effect of NPA on this, suggesting that NPA binding could be exploited to gain insights into structural aspects of PINs related to their transport mechanism.},
author = {Abas, Lindy and Kolb, Martina and Stadlmann, Johannes and Janacek, Dorina P. and Lukic, Kristina and Schwechheimer, Claus and Sazanov, Leonid A and Mach, Lukas and Friml, Jiří and Hammes, Ulrich Z.},
issn = {10916490},
journal = {PNAS},
number = {1},
publisher = {National Academy of Sciences},
title = {{Naphthylphthalamic acid associates with and inhibits PIN auxin transporters}},
doi = {10.1073/pnas.2020857118},
volume = {118},
year = {2021},
}
@article{9287,
abstract = {The phytohormone auxin and its directional transport through tissues are intensively studied. However, a mechanistic understanding of auxin-mediated feedback on endocytosis and polar distribution of PIN auxin transporters remains limited due to contradictory observations and interpretations. Here, we used state-of-the-art methods to reexamine the
auxin effects on PIN endocytic trafficking. We used high auxin concentrations or longer treatments versus lower concentrations and shorter treatments of natural (IAA) and synthetic (NAA) auxins to distinguish between specific and nonspecific effects. Longer treatments of both auxins interfere with Brefeldin A-mediated intracellular PIN2 accumulation and also with general aggregation of endomembrane compartments. NAA treatment decreased the internalization of the endocytic tracer dye, FM4-64; however, NAA treatment also affected the number, distribution, and compartment identity of the early endosome/trans-Golgi network (EE/TGN), rendering the FM4-64 endocytic assays at high NAA concentrations unreliable. To circumvent these nonspecific effects of NAA and IAA affecting the endomembrane system, we opted for alternative approaches visualizing the endocytic events directly at the plasma membrane (PM). Using Total Internal Reflection Fluorescence (TIRF) microscopy, we saw no significant effects of IAA or NAA treatments on the incidence and dynamics of clathrin foci, implying that these treatments do not affect the overall endocytosis rate. However, both NAA and IAA at low concentrations rapidly and specifically promoted endocytosis of photo-converted PIN2 from the PM. These analyses identify a specific effect of NAA and IAA on PIN2 endocytosis, thus contributing to its
polarity maintenance and furthermore illustrate that high auxin levels have nonspecific effects on trafficking and endomembrane compartments. },
author = {Narasimhan, Madhumitha and Gallei, Michelle C and Tan, Shutang and Johnson, Alexander J and Verstraeten, Inge and Li, Lanxin and Rodriguez Solovey, Lesia and Han, Huibin and Himschoot, E and Wang, R and Vanneste, S and Sánchez-Simarro, J and Aniento, F and Adamowski, Maciek and Friml, Jiří},
issn = {1532-2548},
journal = {Plant Physiology},
number = {2},
pages = {1122–1142},
publisher = {Oxford University Press},
title = {{Systematic analysis of specific and nonspecific auxin effects on endocytosis and trafficking}},
doi = {10.1093/plphys/kiab134},
volume = {186},
year = {2021},
}
@article{9290,
abstract = {Polar subcellular localization of the PIN exporters of the phytohormone auxin is a key determinant of directional, intercellular auxin transport and thus a central topic of both plant cell and developmental biology. Arabidopsis mutants lacking PID, a kinase that phosphorylates PINs, or the MAB4/MEL proteins of unknown molecular function display PIN polarity defects and phenocopy pin mutants, but mechanistic insights into how these factors convey PIN polarity are missing. Here, by combining protein biochemistry with quantitative live-cell imaging, we demonstrate that PINs, MAB4/MELs, and AGC kinases interact in the same complex at the plasma membrane. MAB4/MELs are recruited to the plasma membrane by the PINs and in concert with the AGC kinases maintain PIN polarity through limiting lateral diffusion-based escape of PINs from the polar domain. The PIN-MAB4/MEL-PID protein complex has self-reinforcing properties thanks to positive feedback between AGC kinase-mediated PIN phosphorylation and MAB4/MEL recruitment. We thus uncover the molecular mechanism by which AGC kinases and MAB4/MEL proteins regulate PIN localization and plant development.},
author = {Glanc, Matous and Van Gelderen, K and Hörmayer, Lukas and Tan, Shutang and Naramoto, S and Zhang, Xixi and Domjan, David and Vcelarova, L and Hauschild, Robert and Johnson, Alexander J and de Koning, E and van Dop, M and Rademacher, E and Janson, S and Wei, X and Molnar, Gergely and Fendrych, Matyas and De Rybel, B and Offringa, R and Friml, Jiří},
issn = {1879-0445},
journal = {Current Biology},
number = {9},
pages = {1918--1930},
publisher = {Elsevier},
title = {{AGC kinases and MAB4/MEL proteins maintain PIN polarity by limiting lateral diffusion in plant cells}},
doi = {10.1016/j.cub.2021.02.028},
volume = {31},
year = {2021},
}
@article{9443,
abstract = {Endoplasmic reticulum–plasma membrane contact sites (ER–PM CS) play fundamental roles in all eukaryotic cells. Arabidopsis thaliana mutants lacking the ER–PM protein tether synaptotagmin1 (SYT1) exhibit decreased PM integrity under multiple abiotic stresses, such as freezing, high salt, osmotic stress, and mechanical damage. Here, we show that, together with SYT1, the stress-induced SYT3 is an ER–PM tether that also functions in maintaining PM integrity. The ER–PM CS localization of SYT1 and SYT3 is dependent on PM phosphatidylinositol-4-phosphate and is regulated by abiotic stress. Lipidomic analysis revealed that cold stress increased the accumulation of diacylglycerol at the PM in a syt1/3 double mutant relative to wild-type while the levels of most glycerolipid species remain unchanged. In addition, the SYT1-green fluorescent protein fusion preferentially binds diacylglycerol in vivo with little affinity for polar glycerolipids. Our work uncovers a SYT-dependent mechanism of stress adaptation counteracting the detrimental accumulation of diacylglycerol at the PM produced during episodes of abiotic stress.},
author = {Ruiz-Lopez, N and Pérez-Sancho, J and Esteban Del Valle, A and Haslam, RP and Vanneste, S and Catalá, R and Perea-Resa, C and Van Damme, D and García-Hernández, S and Albert, A and Vallarino, J and Lin, J and Friml, Jiří and Macho, AP and Salinas, J and Rosado, A and Napier, JA and Amorim-Silva, V and Botella, MA},
issn = {1532-298x},
journal = {Plant Cell},
number = {7},
pages = {2431--2453},
publisher = {American Society of Plant Biologists},
title = {{Synaptotagmins at the endoplasmic reticulum-plasma membrane contact sites maintain diacylglycerol homeostasis during abiotic stress}},
doi = {10.1093/plcell/koab122},
volume = {33},
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},
}
@unpublished{10095,
abstract = {Growth regulation tailors plant development to its environment. A showcase is response to gravity, where shoots bend up and roots down1. This paradox is based on opposite effects of the phytohormone auxin, which promotes cell expansion in shoots, while inhibiting it in roots via a yet unknown cellular mechanism2. Here, by combining microfluidics, live imaging, genetic engineering and phospho-proteomics in Arabidopsis thaliana, we advance our understanding how auxin inhibits root growth. We show that auxin activates two distinct, antagonistically acting signalling pathways that converge on the rapid regulation of the apoplastic pH, a causative growth determinant. Cell surface-based TRANSMEMBRANE KINASE1 (TMK1) interacts with and mediates phosphorylation and activation of plasma membrane H+-ATPases for apoplast acidification, while intracellular canonical auxin signalling promotes net cellular H+-influx, causing apoplast alkalinisation. The simultaneous activation of these two counteracting mechanisms poises the root for a rapid, fine-tuned growth modulation while navigating complex soil environment.},
author = {Li, Lanxin and Verstraeten, Inge and Roosjen, Mark and Takahashi, Koji and Rodriguez Solovey, Lesia and Merrin, Jack and Chen, Jian and Shabala, Lana and Smet, Wouter and Ren, Hong and Vanneste, Steffen and Shabala, Sergey and De Rybel, Bert and Weijers, Dolf and Kinoshita, Toshinori and Gray, William M. and Friml, Jiří},
booktitle = {Research Square},
issn = {2693-5015},
title = {{Cell surface and intracellular auxin signalling for H+-fluxes in root growth}},
doi = {10.21203/rs.3.rs-266395/v3},
year = {2021},
}
@article{10223,
abstract = {Growth regulation tailors development in plants to their environment. A prominent example of this is the response to gravity, in which shoots bend up and roots bend down1. This paradox is based on opposite effects of the phytohormone auxin, which promotes cell expansion in shoots while inhibiting it in roots via a yet unknown cellular mechanism2. Here, by combining microfluidics, live imaging, genetic engineering and phosphoproteomics in Arabidopsis thaliana, we advance understanding of how auxin inhibits root growth. We show that auxin activates two distinct, antagonistically acting signalling pathways that converge on rapid regulation of apoplastic pH, a causative determinant of growth. Cell surface-based TRANSMEMBRANE KINASE1 (TMK1) interacts with and mediates phosphorylation and activation of plasma membrane H+-ATPases for apoplast acidification, while intracellular canonical auxin signalling promotes net cellular H+ influx, causing apoplast alkalinization. Simultaneous activation of these two counteracting mechanisms poises roots for rapid, fine-tuned growth modulation in navigating complex soil environments.},
author = {Li, Lanxin and Verstraeten, Inge and Roosjen, Mark and Takahashi, Koji and Rodriguez Solovey, Lesia and Merrin, Jack and Chen, Jian and Shabala, Lana and Smet, Wouter and Ren, Hong and Vanneste, Steffen and Shabala, Sergey and De Rybel, Bert and Weijers, Dolf and Kinoshita, Toshinori and Gray, William M. and Friml, Jiří},
issn = {14764687},
journal = {Nature},
keywords = {Multidisciplinary},
number = {7884},
pages = {273--277},
publisher = {Springer Nature},
title = {{Cell surface and intracellular auxin signalling for H+ fluxes in root growth}},
doi = {10.1038/s41586-021-04037-6},
volume = {599},
year = {2021},
}
@inbook{10267,
abstract = {Tropisms are among the most important growth responses for plant adaptation to the surrounding environment. One of the most common tropisms is root gravitropism. Root gravitropism enables the plant to anchor securely to the soil enabling the absorption of water and nutrients. Most of the knowledge related to the plant gravitropism has been acquired from the flowering plants, due to limited research in non-seed plants. Limited research on non-seed plants is due in large part to the lack of standard research methods. Here, we describe the experimental methods to evaluate gravitropism in representative non-seed plant species, including the non-vascular plant moss Physcomitrium patens, the early diverging extant vascular plant lycophyte Selaginella moellendorffii and fern Ceratopteris richardii. In addition, we introduce the methods used for statistical analysis of the root gravitropism in non-seed plant species.},
author = {Zhang, Yuzhou and Li, Lanxin and Friml, Jiří},
booktitle = {Plant Gravitropism},
editor = {Blancaflor, Elison B},
isbn = {978-1-0716-1676-5},
pages = {43--51},
publisher = {Springer Nature},
title = {{Evaluation of gravitropism in non-seed plants}},
doi = {10.1007/978-1-0716-1677-2_2},
volume = {2368},
year = {2021},
}
@phdthesis{9992,
abstract = {Blood – this is what animals use to heal wounds fast and efficient. Plants do not have blood circulation and their cells cannot move. However, plants have evolved remarkable capacities to regenerate tissues and organs preventing further damage. In my PhD research, I studied the wound healing in the Arabidopsis root. I used a UV laser to ablate single cells in the root tip and observed the consequent wound healing. Interestingly, the inner adjacent cells induced a
division plane switch and subsequently adopted the cell type of the killed cell to replace it. We termed this form of wound healing “restorative divisions”. This initial observation triggered the questions of my PhD studies: How and why do cells orient their division planes, how do they feel the wound and why does this happen only in inner adjacent cells.
For answering these questions, I used a quite simple experimental setup: 5 day - old seedlings were stained with propidium iodide to visualize cell walls and dead cells; ablation was carried out using a special laser cutter and a confocal microscope. Adaptation of the novel vertical microscope system made it possible to observe wounds in real time. This revealed that restorative divisions occur at increased frequency compared to normal divisions. Additionally,
the major plant hormone auxin accumulates in wound adjacent cells and drives the expression of the wound-stress responsive transcription factor ERF115. Using this as a marker gene for wound responses, we found that an important part of wound signalling is the sensing of the collapse of the ablated cell. The collapse causes a radical pressure drop, which results in strong tissue deformations. These deformations manifest in an invasion of the now free spot specifically by the inner adjacent cells within seconds, probably because of higher pressure of the inner tissues. Long-term imaging revealed that those deformed cells continuously expand towards the wound hole and that this is crucial for the restorative division. These wound-expanding cells exhibit an abnormal, biphasic polarity of microtubule arrays
before the division. Experiments inhibiting cell expansion suggest that it is the biphasic stretching that induces those MT arrays. Adapting the micromanipulator aspiration system from animal scientists at our institute confirmed the hypothesis that stretching influences microtubule stability. In conclusion, this shows that microtubules react to tissue deformation
and this facilitates the observed division plane switch. This puts mechanical cues and tensions at the most prominent position for explaining the growth and wound healing properties of plants. Hence, it shines light onto the importance of understanding mechanical signal transduction. },
author = {Hörmayer, Lukas},
issn = {2663-337X},
pages = {168},
publisher = {Institute of Science and Technology Austria},
title = {{Wound healing in the Arabidopsis root meristem}},
doi = {10.15479/at:ista:9992},
year = {2021},
}