Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
In plants, the cortical endoplasmic reticulum (ER) network is connected to the plasma membrane (PM) through the ER-PM contact sites (EPCSs), whose structures are maintained by EPCS resident proteins and the cytoskeleton.1-7 Strong co-alignment between EPCSs and the cytoskeleton is observed in plants,1,8 but little is known of how the cytoskeleton is maintained and regulated at the EPCS. Here, we have used a yeast-two-hybrid screen and subsequent in vivo interaction studies in plants by fluorescence resonance energy transfer (FRET)-fluorescence lifetime imaging microscopy (FLIM) analysis to identify two microtubule binding proteins, KLCR1 (kinesin-light-chain-related protein 1) and IQD2 (IQ67-domain 2), that interact with the actin binding protein NET3C and form a component of plant EPCS that mediates the link between the actin and microtubule networks. The NET3C-KLCR1-IQD2 module, acting as an actin-microtubule bridging complex, has a direct influence on ER morphology and EPCS structure. Their loss-of-function mutants, net3a/NET3C RNAi, klcr1, or iqd2, exhibit defects in pavement cell morphology, which we suggest is linked to the disorganization of both actin filaments and microtubules. In conclusion, our results reveal a novel cytoskeletal-associated complex, which is essential for the maintenance and organization of cytoskeletal structure and ER morphology at the EPCS and for normal plant cell morphogenesis.
Publikation
Vaddepalli, P.; de Zeeuw, T.; Strauss, S.; Bürstenbinder, K.; Liao, C.-Y.; Ramalho, J. J.; Smith, R. S.; Weijers, D.;Auxin-dependent control of cytoskeleton and cell shape regulates division orientation in the Arabidopsis embryoCurr. Biol.314946-4955(2021)DOI: 10.1016/j.cub.2021.09.019
Premitotic
control of cell division orientation is critical for plant development,
as cell walls prevent extensive cell remodeling or migration. While
many divisions are proliferative and add cells to existing tissues, some
divisions are formative and generate new tissue layers or growth axes.
Such formative divisions are often asymmetric in nature, producing
daughters with different fates. We have previously shown that, in the Arabidopsis thaliana
embryo, developmental asymmetry is correlated with geometric asymmetry,
creating daughter cells of unequal volume. Such divisions are generated
by division planes that deviate from a default “minimal surface area”
rule. Inhibition of auxin response leads to reversal to this default,
yet the mechanisms underlying division plane choice in the embryo have
been unclear. Here, we show that auxin-dependent division plane control
involves alterations in cell geometry, but not in cell polarity axis or nuclear position. Through transcriptome profiling, we find that auxin regulates genes controlling cell wall and cytoskeleton
properties. We confirm the involvement of microtubule (MT)-binding
proteins in embryo division control. Organization of both MT and actin cytoskeleton depends on auxin response, and genetically controlled MT or actin depolymerization
in embryos leads to disruption of asymmetric divisions, including
reversion to the default. Our work shows how auxin-dependent control of
MT and actin cytoskeleton properties interacts with cell geometry to
generate asymmetric divisions during the earliest steps in plant
development.Graphical abstract
Publikation
Schuster, M.; van der Hoorn, R. A.;Plant biology: distinct new players in processing peptide hormones during abscissionCurr. Biol.30R715-R717(2020)DOI: 10.1016/j.cub.2020.04.072
Flower organ abscission in Arabidopsis is regulated by a peptide hormone that is released from its precursor by a network of redundant subtilases. An exciting new study describes how drought-induced flower abscission in tomato is regulated similarly, but distinctly via a single, different subtilase that releases a very different peptide hormone.