@article{JantzenWozniakKappeletal.2019, author = {Jantzen, Friederike and Wozniak, Natalia Joanna and Kappel, Christian and Sicard, Adrien and Lenhard, Michael}, title = {A high‑throughput amplicon‑based method for estimating outcrossing rates}, series = {Plant Methods}, volume = {15}, journal = {Plant Methods}, number = {47}, publisher = {BioMed Central}, address = {London}, issn = {1746-4811}, doi = {10.1186/s13007-019-0433-9}, pages = {14}, year = {2019}, abstract = {Background: The outcrossing rate is a key determinant of the population-genetic structure of species and their long-term evolutionary trajectories. However, determining the outcrossing rate using current methods based on PCRgenotyping individual offspring of focal plants for multiple polymorphic markers is laborious and time-consuming. Results: We have developed an amplicon-based, high-throughput enabled method for estimating the outcrossing rate and have applied this to an example of scented versus non-scented Capsella (Shepherd's Purse) genotypes. Our results show that the method is able to robustly capture differences in outcrossing rates. They also highlight potential biases in the estimates resulting from differential haplotype sharing of the focal plants with the pollen-donor population at individual amplicons. Conclusions: This novel method for estimating outcrossing rates will allow determining this key population-genetic parameter with high-throughput across many genotypes in a population, enabling studies into the genetic determinants of successful pollinator attraction and outcrossing.}, language = {en} } @misc{KappelCuongNguyenHuuLenhard2017, author = {Kappel, Christian and Cuong Nguyen Huu, and Lenhard, Michael}, title = {A short story gets longer: recent insights into the molecular basis of heterostyly}, series = {Journal of experimental botany}, volume = {68}, journal = {Journal of experimental botany}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0022-0957}, doi = {10.1093/jxb/erx387}, pages = {5719 -- 5730}, year = {2017}, abstract = {Heterostyly is a fascinating adaptation to promote outbreeding and a classical paradigm of botany. In the most common type of heterostyly, plants either form flowers with long styles and short stamens, or short styles and long stamens. This reciprocal organ positioning reduces pollen wastage and promotes cross-pollination, thus increasing male fitness. In addition, in many heterostylous species selfing and the generation of unfit progeny due to inbreeding depression is limited by a self-incompatibility system, thus promoting female fitness. The two floral forms are genetically determined by the S locus as a complex supergene, namely a chromosomal region containing several individual genes that control the different traits, such as style or stamen length, and are held together by very tight linkage due to suppressed recombination. Recent molecular-genetic studies in several systems, including Turnera, Fagopyrum, Linum, and Primula have begun to identify and characterize the causal heterostyly genes residing at the S locus. An emerging theme from several families is that the dominant S haplotype represents a hemizygous region not present on the recessive s haplotype. This provides an explanation for the suppressed recombination and suggests a scenario for the chromosomal evolution of the S locus. In this review, we discuss the results from recent molecular-genetic analyses in light of the classical models on the genetics and evolution of heterostyly.}, language = {en} } @unpublished{Lenhard2012, author = {Lenhard, Michael}, title = {All's well that ends well arresting cell proliferation in leaves}, series = {Developmental cell}, volume = {22}, journal = {Developmental cell}, number = {1}, publisher = {Cell Press}, address = {Cambridge}, issn = {1534-5807}, doi = {10.1016/j.devcel.2011.12.004}, pages = {9 -- 11}, year = {2012}, abstract = {The transition from cell proliferation to cell expansion is critical for determining leaf size. Andriankaja et al. (2012) demonstrate that in leaves of dicotyledonous plants, a basal proliferation zone is maintained for several days before abruptly disappearing, and that chloroplast differentiation is required to trigger the onset of cell expansion.}, language = {en} } @article{CzesnickLenhard2016, author = {Czesnick, Hj{\"o}rdis and Lenhard, Michael}, title = {Antagonistic control of flowering time by functionally specialized poly(A) polymerases in Arabidopsis thaliana}, series = {The plant journal}, volume = {88}, journal = {The plant journal}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0960-7412}, doi = {10.1111/tpj.13280}, pages = {570 -- 583}, year = {2016}, abstract = {Polyadenylation is a critical 3-end processing step during maturation of pre-mRNAs, and the length of the poly(A) tail affects mRNA stability, nuclear export and translation efficiency. The Arabidopsis thaliana genome encodes three canonical nuclear poly(A) polymerase (PAPS) isoforms fulfilling specialized functions, as reflected by their different mutant phenotypes. While PAPS1 affects several processes, such as the immune response, organ growth and male gametophyte development, the roles of PAPS2 and PAPS4 are largely unknown. Here we demonstrate that PAPS2 and PAPS4 promote flowering in a partially redundant manner. The enzymes act antagonistically to PAPS1, which delays the transition to flowering. The opposite flowering-time phenotypes in paps1 and paps2 paps4 mutants are at least partly due to decreased or increased FLC activity, respectively. In contrast to paps2 paps4 mutants, plants with increased PAPS4 activity flower earlier than the wild-type, concomitant with reduced FLC expression. Double mutant analyses suggest that PAPS2 and PAPS4 act independently of the autonomous pathway components FCA, FY and CstF64. The direct polyadenylation targets of the three PAPS isoforms that mediate their effects on flowering time do not include FLC sense mRNA and remain to be identified. Thus, our results uncover a role for canonical PAPS isoforms in flowering-time control, raising the possibility that modulating the balance of the isoform activities could be used to fine tune the transition to flowering. Significance Statement The length of the poly(A) tail affects mRNA stability, nuclear export and translation efficiency. Arabidopsis has three isoforms of nuclear poly(A) polymerase (PAPS): PAPS1 plays a major role in organ growth and plant defence. Here we show that PAPS2 and PAPS4 redundantly promote flowering and act antagonistically to PAPS1, which delays flowering. We suggest that modulating the activity of these isoforms fine-tunes the transition to flowering.}, language = {en} } @article{TrostViCzesnicketal.2014, author = {Trost, Gerda and Vi, Son Lang and Czesnick, Hj{\"o}rdis and Lange, Peggy and Holton, Nick and Giavalisco, Patrick and Zipfel, Cyril and Kappel, Christian and Lenhard, Michael}, title = {Arabidopsis poly(A) polymerase PAPS1 limits founder-cell recruitment to organ primordia and suppresses the salicylic acid-independent immune response downstream of EDS1/PAD4}, series = {The plant journal}, volume = {77}, journal = {The plant journal}, number = {5}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0960-7412}, doi = {10.1111/tpj.12421}, pages = {688 -- 699}, year = {2014}, abstract = {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.}, language = {en} } @article{BollierSicardLeblondetal.2018, author = {Bollier, Norbert and Sicard, Adrien and Leblond, Julie and Latrasse, David and Gonzalez, Nathalie and Gevaudant, Frederic and Benhamed, Moussa and Raynaud, Cecile and Lenhard, Michael and Chevalier, Christian and Hernould, Michel and Delmas, Frederic}, title = {At-MINI ZINC FINGER2 and Sl-INHIBITOR OF MERISTEM ACTIVITY, a Conserved Missing Link in the Regulation of Floral Meristem Termination in Arabidopsis and Tomato}, series = {The plant cell}, volume = {30}, journal = {The plant cell}, number = {1}, publisher = {American Society of Plant Physiologists}, address = {Rockville}, issn = {1040-4651}, doi = {10.1105/tpc.17.00653}, pages = {83 -- 100}, year = {2018}, abstract = {In angiosperms, the gynoecium is the last structure to develop within the flower due to the determinate fate of floral meristem (FM) stem cells. The maintenance of stem cell activity before its arrest at the stage called FM termination affects the number of carpels that develop. The necessary inhibition at this stage of WUSCHEL (WUS), which is responsible for stem cell maintenance, involves a two-step mechanism. Direct repression mediated by the MADS domain transcription factor AGAMOUS (AG), followed by indirect repression requiring the C2H2 zinc-finger protein KNUCKLES (KNU), allow for the complete termination of floral stem cell activity. Here, we show that Arabidopsis thaliana MINI ZINC FINGER2 (AtMIF2) and its homolog in tomato (Solanum lycopersicum), INHIBITOR OF MERISTEM ACTIVITY (SlIMA), participate in the FM termination process by functioning as adaptor proteins. AtMIF2 and SlIMA recruit AtKNU and SlKNU, respectively, to form a transcriptional repressor complex together with TOPLESS and HISTONE DEACETYLASE19. AtMIF2 and SlIMA bind to the WUS and SIWUS loci in the respective plants, leading to their repression. These results provide important insights into the molecular mechanisms governing (FM) termination and highlight the essential role of AtMIF2/SlIMA during this developmental step, which determines carpel number and therefore fruit size.}, language = {en} } @article{FujikuraElsaesserBreuningeretal.2014, author = {Fujikura, Ushio and Elsaesser, Lore and Breuninger, Holger and Sanchez-Rodriguez, Clara and Ivakov, Alexander and Laux, Thomas and Findlay, Kim and Persson, Staffan and Lenhard, Michael}, title = {Atkinesin-13A modulates cell-wall synthesis and cell expansion in arabidopsis thaliana via the THESEUS1 pathway}, series = {PLoS Genetics : a peer-reviewed, open-access journal}, volume = {10}, journal = {PLoS Genetics : a peer-reviewed, open-access journal}, number = {9}, publisher = {PLoS}, address = {San Fransisco}, issn = {1553-7390}, doi = {10.1371/journal.pgen.1004627}, pages = {15}, year = {2014}, abstract = {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.}, language = {en} } @misc{SicardLenhard2018, author = {Sicard, Adrien and Lenhard, Michael}, title = {Capsella}, series = {Current biology}, volume = {28}, journal = {Current biology}, number = {17}, publisher = {Cell Press}, address = {Cambridge}, issn = {0960-9822}, doi = {10.1016/j.cub.2018.06.033}, pages = {R920 -- R921}, year = {2018}, language = {en} } @article{PotenteLeveilleBourretYousefietal.2022, author = {Potente, Giacomo and L{\´e}veill{\´e}-Bourret, {\´E}tienne and Yousefi, Narjes and Choudhury, Rimjhim Roy and Keller, Barbara and Diop, Seydina Issa and Duijsings, Dani{\"e}l and Pirovano, Walter and Lenhard, Michael and Sz{\"o}v{\´e}nyi, P{\´e}ter and Conti, Elena}, title = {Comparative genomics elucidates the origin of a supergene controlling floral heteromorphism}, series = {Molecular biology and evolution : MBE}, volume = {39}, journal = {Molecular biology and evolution : MBE}, number = {2}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0737-4038}, doi = {10.1093/molbev/msac035}, pages = {16}, year = {2022}, abstract = {Supergenes are nonrecombining genomic regions ensuring the coinheritance of multiple, coadapted genes. Despite the importance of supergenes in adaptation, little is known on how they originate. A classic example of supergene is the S locus controlling heterostyly, a floral heteromorphism occurring in 28 angiosperm families. In Primula, heterostyly is characterized by the cooccurrence of two complementary, self-incompatible floral morphs and is controlled by five genes clustered in the hemizygous, ca. 300-kb S locus. Here, we present the first chromosome-scale genome assembly of any heterostylous species, that of Primula veris (cowslip). By leveraging the high contiguity of the P. veris assembly and comparative genomic analyses, we demonstrated that the S-locus evolved via multiple, asynchronous gene duplications and independent gene translocations. Furthermore, we discovered a new whole-genome duplication in Ericales that is specific to the Primula lineage. We also propose a mechanism for the origin of S-locus hemizygosity via nonhomologous recombination involving the newly discovered two pairs of CFB genes flanking the S locus. Finally, we detected only weak signatures of degeneration in the S locus, as predicted for hemizygous supergenes. The present study provides a useful resource for future research addressing key questions on the evolution of supergenes in general and the S locus in particular: How do supergenes arise? What is the role of genome architecture in the evolution of complex adaptations? Is the molecular architecture of heterostyly supergenes across angiosperms similar to that of Primula?}, language = {en} } @article{KahlLenhardJoshi2019, author = {Kahl, Sandra M. and Lenhard, Michael and Joshi, Jasmin Radha}, title = {Compensatory mechanisms to climate change in the widely distributed species Silene vulgaris}, series = {The journal of ecology}, volume = {107}, journal = {The journal of ecology}, number = {4}, publisher = {Wiley}, address = {Hoboken}, issn = {0022-0477}, doi = {10.1111/1365-2745.13133}, pages = {1918 -- 1930}, year = {2019}, abstract = {The adaptation of plants to future climatic conditions is crucial for their survival. Not surprisingly, phenotypic responses to climate change have already been observed in many plant populations. These responses may be due to evolutionary adaptive changes or phenotypic plasticity. Especially plant species with a wide geographic range are either expected to show genetic differentiation in response to differing climate conditions or to have a high phenotypic plasticity. We investigated phenotypic responses and plasticity as an estimate of the adaptive potential in the widespread species Silene vulgaris. In a greenhouse experiment, 25 European populations covering a geographic range from the Canary Islands to Sweden were exposed to three experimental precipitation and two temperature regimes mimicking a possible climate-change scenario for central Europe. We hypothesized that southern populations have a better performance under high temperature and drought conditions, as they are already adapted to a comparable environment. We found that our treatments significantly influenced the plants, but did not reveal a latitudinal difference in response to climate treatments for most plant traits. Only flower number showed a stronger plasticity in northern European populations (e.g. Swedish populations) where numbers decreased more drastically with increased temperature and decreased precipitation treatment. Synthesis. The significant treatment response in Silene vulgaris, independent of population origin - except for the number of flowers produced - suggests a high degree of universal phenotypic plasticity in this widely distributed species. This reflects the likely adaptation strategy of the species and forms the basis for a successful survival strategy during upcoming climatic changes. However, as flower number, a strongly fitness-related trait, decreased more strongly in northern populations under a climate-change scenario, there might be limits to adaptation even in this widespread, plastic species.}, language = {en} }