@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{CuongNguyenHuuKappelKelleretal.2016, author = {Cuong Nguyen Huu, and Kappel, Christian and Keller, Barbara and Sicard, Adrien and Takebayashi, Yumiko and Breuninger, Holger and Nowak, Michael D. and B{\"a}urle, Isabel and Himmelbach, Axel and Burkart, Michael and Ebbing-Lohaus, Thomas and Sakakibara, Hitoshi and Altschmied, Lothar and Conti, Elena and Lenhard, Michael}, title = {Presence versus absence of CYP734A50 underlies the style-length dimorphism in primroses}, series = {eLife}, volume = {5}, journal = {eLife}, publisher = {eLife Sciences Publications}, address = {Cambridge}, issn = {2050-084X}, doi = {10.7554/eLife.17956}, pages = {15}, year = {2016}, abstract = {Heterostyly is a wide-spread floral adaptation to promote outbreeding, yet its genetic basis and evolutionary origin remain poorly understood. In Primula (primroses), heterostyly is controlled by the S-locus supergene that determines the reciprocal arrangement of reproductive organs and incompatibility between the two morphs. However, the identities of the component genes remain unknown. Here, we identify the Primula CYP734A50 gene, encoding a putative brassinosteroid-degrading enzyme, as the G locus that determines the style-length dimorphism. CYP734A50 is only present on the short-styled S-morph haplotype, it is specifically expressed in S-morph styles, and its loss or inactivation leads to long styles. The gene arose by a duplication specific to the Primulaceae lineage and shows an accelerated rate of molecular evolution. Thus, our results provide a mechanistic explanation for the Primula style-length dimorphism and begin to shed light on the evolution of the S-locus as a prime model for a complex plant supergene.}, language = {en} } @article{EldridgeLangowskiStaceyetal.2016, author = {Eldridge, Tilly and Langowski, Lukasz and Stacey, Nicola and Jantzen, Friederike and Moubayidin, Laila and Sicard, Adrien and Southam, Paul and Kennaway, Richard and Lenhard, Michael and Coen, Enrico S. and Ostergaard, Lars}, title = {Fruit shape diversity in the Brassicaceae is generated by varying patterns of anisotropy}, series = {Development : Company of Biologists}, volume = {143}, journal = {Development : Company of Biologists}, publisher = {Company of Biologists Limited}, address = {Cambridge}, issn = {0950-1991}, doi = {10.1242/dev.135327}, pages = {3394 -- 3406}, year = {2016}, abstract = {Fruits exhibit a vast array of different 3D shapes, from simple spheres and cylinders to more complex curved forms; however, the mechanism by which growth is oriented and coordinated to generate this diversity of forms is unclear. Here, we compare the growth patterns and orientations for two very different fruit shapes in the Brassicaceae: the heart-shaped Capsella rubella silicle and the near-cylindrical Arabidopsis thaliana silique. We show, through a combination of clonal and morphological analyses, that the different shapes involve different patterns of anisotropic growth during three phases. These experimental data can be accounted for by a tissue level model in which specified growth rates vary in space and time and are oriented by a proximodistal polarity field. The resulting tissue conflicts lead to deformation of the tissue as it grows. The model allows us to identify tissue-specific and temporally specific activities required to obtain the individual shapes. One such activity may be provided by the valve-identity gene FRUITFULL, which we show through comparative mutant analysis to modulate fruit shape during post-fertilisation growth of both species. Simple modulations of the model presented here can also broadly account for the variety of shapes in other Brassicaceae species, thus providing a simplified framework for fruit development and shape diversity.}, language = {en} } @misc{FritzRosaSicard2018, author = {Fritz, Michael Andre and Rosa, Stefanie and Sicard, Adrien}, title = {Mechanisms Underlying the Environmentally Induced Plasticity of Leaf Morphology}, series = {Frontiers in genetics}, volume = {9}, journal = {Frontiers in genetics}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-8021}, doi = {10.3389/fgene.2018.00478}, pages = {25}, year = {2018}, abstract = {The primary function of leaves is to provide an interface between plants and their environment for gas exchange, light exposure and thermoregulation. Leaves have, therefore a central contribution to plant fitness by allowing an efficient absorption of sunlight energy through photosynthesis to ensure an optimal growth. Their final geometry will result from a balance between the need to maximize energy uptake while minimizing the damage caused by environmental stresses. This intimate relationship between leaf and its surroundings has led to an enormous diversification in leaf forms. Leaf shape varies between species, populations, individuals or even within identical genotypes when those are subjected to different environmental conditions. For instance, the extent of leaf margin dissection has, for long, been found to inversely correlate with the mean annual temperature, such that Paleobotanists have used models based on leaf shape to predict the paleoclimate from fossil flora. Leaf growth is not only dependent on temperature but is also regulated by many other environmental factors such as light quality and intensity or ambient humidity. This raises the question of how the different signals can be integrated at the molecular level and converted into clear developmental decisions. Several recent studies have started to shed the light on the molecular mechanisms that connect the environmental sensing with organ-growth and patterning. In this review, we discuss the current knowledge on the influence of different environmental signals on leaf size and shape, their integration as well as their importance for plant adaptation.}, language = {en} } @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} } @article{JoestHenselKappeletal.2016, author = {J{\"o}st, Moritz and Hensel, Goetz and Kappel, Christian and Druka, Arnis and Sicard, Adrien and Hohmann, Uwe and Beier, Sebastian and Himmelbach, Axel and Waugh, Robbie and Kumlehn, Jochen and Stein, Nils and Lenhard, Michael}, title = {The INDETERMINATE DOMAIN Protein BROAD LEAF1 Limits Barley Leaf Width by Restricting Lateral Proliferation}, series = {Current biology}, volume = {26}, journal = {Current biology}, publisher = {Cell Press}, address = {Cambridge}, issn = {0960-9822}, doi = {10.1016/j.cub.2016.01.047}, pages = {903 -- 909}, year = {2016}, abstract = {Variation in the size, shape, and positioning of leaves as the major photosynthetic organs strongly impacts crop yield, and optimizing these aspects is a central aim of cereal breeding [1, 2]. Leaf growth in grasses is driven by cell proliferation and cell expansion in a basal growth zone [3]. Although several factors influencing final leaf size and shape have been identified from rice and maize [4-14], what limits grass leaf growth in the longitudinal or transverse directions during leaf development remains poorly understood. To identify factors involved in this process, we characterized the barley mutant broad leaf1 (blf1). Mutants form wider but slightly shorter leaves due to changes in the numbers of longitudinal cell files and of cells along the leaf length. These differences arise during primordia outgrowth because of more cell divisions in the width direction increasing the number of cell files. Positional cloning, analysis of independent alleles, and transgenic complementation confirm that BLF1 encodes a presumed transcriptional regulator of the INDETERMINATE DOMAIN family. In contrast to loss-of-function mutants, moderate overexpression of BLF1 decreases leaf width below wild-type levels. A functional BLF1-vYFP fusion protein expressed from the endogenous promoter shows a dynamic expression pattern in the shoot apical meristem and young leaf primordia. Thus, we propose that the BLF1 gene regulates barley leaf size by restricting cell proliferation in the leaf-width direction. Given the agronomic importance of canopy traits in cereals, identifying functionally different BLF1 alleles promises to allow for the generation of optimized cereal ideotypes.}, language = {en} } @article{LohmannStaceyBreuningeretal.2010, author = {Lohmann, Daniel and Stacey, Nicola and Breuninger, Holger and Jikumaru, Yusuke and M{\"u}ller, D{\"o}rte and Sicard, Adrien and Leyser, Ottoline and Yamaguchi, Shinjiro and Lenhard, Michael}, title = {SLOW MOTION is required for within-plant auxin homeostasis and normal timing of lateral organ initiation at the shoot meristem in Arabidopsis}, issn = {1040-4651}, year = {2010}, language = {en} } @article{MathieuRivetGevaudantSicardetal.2010, author = {Mathieu-Rivet, Elodie and G{\´e}vaudant, Fr{\´e}d{\´e}ric and Sicard, Adrien and Salar, Sophie and Do, Phuc Thi and Mouras, Armand and Fernie, Alisdair R. and Gibon, Yves and Rothan, Christophe and Chevalier, Christian and Hernould, Michel}, title = {Functional analysis of the anaphase promoting complex activator CCS52A highlights the crucial role of endo- reduplication for fruit growth in tomato}, issn = {1365-313X}, year = {2010}, language = {en} } @article{SicardKappelJosephsetal.2015, author = {Sicard, Adrien and Kappel, Christian and Josephs, Emily B. and Lee, Young Wha and Marona, Cindy and Stinchcombe, John R. and Wright, Stephen I. and Lenhard, Michael}, title = {Divergent sorting of a balanced ancestral polymorphism underlies the establishment of gene-flow barriers in Capsella}, series = {Nature Communications}, volume = {6}, journal = {Nature Communications}, publisher = {Nature Publ. Group}, address = {London}, issn = {2041-1723}, doi = {10.1038/ncomms8960}, pages = {10}, year = {2015}, abstract = {In the Bateson-Dobzhansky-Muller model of genetic incompatibilities post-zygotic gene-flow barriers arise by fixation of novel alleles at interacting loci in separated populations. Many such incompatibilities are polymorphic in plants, implying an important role for genetic drift or balancing selection in their origin and evolution. Here we show that NPR1 and RPP5 loci cause a genetic incompatibility between the incipient species Capsella grandiflora and C. rubella, and the more distantly related C. rubella and C. orientalis. The incompatible RPP5 allele results from a mutation in C. rubella, while the incompatible NPR1 allele is frequent in the ancestral C. grandiflora. Compatible and incompatible NPR1 haplotypes are maintained by balancing selection in C. grandiflora, and were divergently sorted into the derived C. rubella and C. orientalis. Thus, by maintaining differentiated alleles at high frequencies, balancing selection on ancestral polymorphisms can facilitate establishing gene-flow barriers between derived populations through lineage sorting of the alternative alleles.}, language = {en} } @article{SicardKappelJosephsetal.2015, author = {Sicard, Adrien and Kappel, Christian and Josephs, Emily B. and Wha Lee, Young and Marona, Cindy and Stinchcombe, John R. and Wright, Stephen I. and Lenhard, Michael}, title = {Divergent sorting of a balanced ancestral polymorphism underlies the establishment of gene-flow barriers in Capsella}, series = {Nature Communications}, volume = {6}, journal = {Nature Communications}, publisher = {Nature Publishing Group}, address = {London}, issn = {2041-1723}, doi = {10.1038/ncomms8960}, year = {2015}, abstract = {In the Bateson-Dobzhansky-Muller model of genetic incompatibilities post-zygotic gene-flow barriers arise by fixation of novel alleles at interacting loci in separated populations. Many such incompatibilities are polymorphic in plants, implying an important role for genetic drift or balancing selection in their origin and evolution. Here we show that NPR1 and RPP5 loci cause a genetic incompatibility between the incipient species Capsella grandiflora and C. rubella, and the more distantly related C. rubella and C. orientalis. The incompatible RPP5 allele results from a mutation in C. rubella, while the incompatible NPR1 allele is frequent in the ancestral C. grandiflora. Compatible and incompatible NPR1 haplotypes are maintained by balancing selection in C. grandiflora, and were divergently sorted into the derived C. rubella and C. orientalis. Thus, by maintaining differentiated alleles at high frequencies, balancing selection on ancestral polymorphisms can facilitate establishing gene-flow barriers between derived populations through lineage sorting of the alternative alleles.}, language = {en} }