TY - JOUR A1 - Fujikura, Ushio A1 - Elsaesser, Lore A1 - Breuninger, Holger A1 - Sanchez-Rodriguez, Clara A1 - Ivakov, Alexander A1 - Laux, Thomas A1 - Findlay, Kim A1 - Persson, Staffan A1 - Lenhard, Michael T1 - Atkinesin-13A modulates cell-wall synthesis and cell expansion in arabidopsis thaliana via the THESEUS1 pathway JF - PLoS Genetics : a peer-reviewed, open-access journal N2 - Growth of plant organs relies on cell proliferation and expansion. While an increasingly detailed picture about the control of cell proliferation is emerging, our knowledge about the control of cell expansion remains more limited. We demonstrate the internal-motor kinesin AtKINESIN-13A (AtKIN13A) limits cell expansion and cell size in Arabidopsis thaliana, ion atkinl3a mutants forming larger petals with larger cells. The homolog, AtKINESIN-13B, also affects cell expansion and double mutants display growth, gametophytic and early embryonic defects, indicating a redundant role of he two genes. AtKIN13A is known to depolymerize microtubules and influence Golgi motility and distribution. Consistent his function, AtKIN13A interacts genetically with ANGUSTIFOLIA, encoding a regulator of Golgi dynamics. Reduced AtIGN13A activity alters cell wall structure as assessed by Fourier-transformed infrared-spectroscopy and triggers signalling he THESEUS1-dependent cell-wall integrity pathway, which in turn promotes the excess cell expansion in the atkinl3a mutant. Thus, our results indicate that the intracellular activity of AtKIN13A regulates cell expansion and wall architecture via THESEUS1, providing a compelling case of interplay between cell wall integrity sensing and expansion. Y1 - 2014 U6 - https://doi.org/10.1371/journal.pgen.1004627 SN - 1553-7390 SN - 1553-7404 VL - 10 IS - 9 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Hepworth, Jo A1 - Lenhard, Michael T1 - Regulation of plant lateral-organ growth by modulating cell number and size JF - Current opinion in plant biology N2 - Leaves and floral organs grow to distinct, species-specific sizes and shapes. Research over the last few years has increased our understanding of how genetic pathways modulate cell proliferation and cell expansion to determine these sizes and shapes. In particular, the timing of proliferation arrest is an important point of control for organ size, and work on the regulators involved is showing how this control is achieved mechanistically and integrates environmental information. We are also beginning to understand how growth differs in different organs to produce their characteristic shapes, and how growth is integrated between different tissues that make up plant organs. Lastly, components of the general machinery in eukaryotic cells have been identified as having important roles in growth control. Y1 - 2014 U6 - https://doi.org/10.1016/j.pbi.2013.11.005 SN - 1369-5266 SN - 1879-0356 VL - 17 SP - 36 EP - 42 PB - Elsevier CY - London ER - TY - JOUR A1 - Sicard, Adrien A1 - Thamm, Anna A1 - Marona, Cindy A1 - Lee, Young Wha A1 - Wahl, Vanessa A1 - Stinchcombe, John R. A1 - Wright, Stephen I. A1 - Kappel, Christian A1 - Lenhard, Michael T1 - Repeated evolutionary changes of leaf morphology caused by mutations to a homeobox gene JF - Current biology N2 - Elucidating the genetic basis of morphological changes in evolution remains a major challenge in biology [1-3]. Repeated independent trait changes are of particular interest because they can indicate adaptation in different lineages or genetic and developmental constraints on generating morphological variation [4-6]. In animals, changes to "hot spot" genes with minimal pleiotropy and large phenotypic effects underlie many cases of repeated morphological transitions [4-8]. By contrast, only few such genes have been identified from plants [8-11], limiting cross-kingdom comparisons of the principles of morphological evolution. Here, we demonstrate that the REDUCED COMPLEXITY (RCO) locus [12] underlies more than one naturally evolved change in leaf shape in the Brassicaceae. We show that the difference in leaf margin dissection between the sister species Capsella rubella and Capsella grandiflora is caused by cis-regulatory variation in the homeobox gene RCO-A, which alters its activity in the developing lobes of the leaf. Population genetic analyses in the ancestral C. grandiflora indicate that the more-active C. rubella haplotype is derived from a now rare or lost C. grandiflora haplotype via additional mutations. In Arabidopsis thaliana, the deletion of the RCO-A and RCO-B genes has contributed to its evolutionarily derived smooth leaf margin [12], suggesting the RCO locus as a candidate for an evolutionary hot spot. We also find that temperature-responsive expression of RCO-A can explain the phenotypic plasticity of leaf shape to ambient temperature in Capsella, suggesting a molecular basis for the well-known negative correlation between temperature and leaf margin dissection. Y1 - 2014 U6 - https://doi.org/10.1016/j.cub.2014.06.061 SN - 0960-9822 SN - 1879-0445 VL - 24 IS - 16 SP - 1880 EP - 1886 PB - Cell Press CY - Cambridge ER - TY - JOUR A1 - Trost, Gerda A1 - Vi, Son Lang A1 - Czesnick, Hjördis A1 - Lange, Peggy A1 - Holton, Nick A1 - Giavalisco, Patrick A1 - Zipfel, Cyril A1 - Kappel, Christian A1 - Lenhard, Michael T1 - Arabidopsis poly(A) polymerase PAPS1 limits founder-cell recruitment to organ primordia and suppresses the salicylic acid-independent immune response downstream of EDS1/PAD4 JF - The plant journal N2 - Polyadenylation of pre-mRNAs by poly(A) polymerase (PAPS) is a critical process in eukaryotic gene expression. As found in vertebrates, plant genomes encode several isoforms of canonical nuclear PAPS enzymes. In Arabidopsis thaliana these isoforms are functionally specialized, with PAPS1 affecting both organ growth and immune response, at least in part by the preferential polyadenylation of subsets of pre-mRNAs. Here, we demonstrate that the opposite effects of PAPS1 on leaf and flower growth reflect the different identities of these organs, and identify a role for PAPS1 in the elusive connection between organ identity and growth patterns. The overgrowth of paps1 mutant petals is due to increased recruitment of founder cells into early organ primordia, and suggests that PAPS1 activity plays unique roles in influencing organ growth. By contrast, the leaf phenotype of paps1 mutants is dominated by a constitutive immune response that leads to increased resistance to the biotrophic oomycete Hyaloperonospora arabidopsidis and reflects activation of the salicylic acid-independent signalling pathway downstream of ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1)/PHYTOALEXIN DEFICIENT4 (PAD4). These findings provide an insight into the developmental and physiological basis of the functional specialization amongst plant PAPS isoforms. KW - poly(A) polymerase KW - founder-cell recruitment KW - organ growth KW - polyadenylation Y1 - 2014 U6 - https://doi.org/10.1111/tpj.12421 SN - 0960-7412 SN - 1365-313X VL - 77 IS - 5 SP - 688 EP - 699 PB - Wiley-Blackwell CY - Hoboken ER -