Michael Lenhard

Universität Potsdam · Genetics

Background The flowering plant Primula veris is a common spring blooming perennial that is widely cultivated throughout Europe. This species is an established model system in the study of the genetics, evolution, and ecology of heterostylous floral polymorphisms. Despite the long history of research focused on this and related species, the continue...

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 spo...

Polyadenylation of pre-mRNAs is critical for efficient nuclear export, stability, and translation of the mature mRNAs, and thus for gene expression. The bulk of pre-mRNAs are processed by canonical nuclear poly(A) polymerase (PAPS). Both vertebrate and higher-plant genomes encode more than one isoform of this enzyme, and these are coexpressed in di...

Genetic transformation is a powerful tool in plant biotechnology. However, its application is limited to species that are well‐studied and easy to transform. There is a critical need to establish transformation protocols for non‐model species. A stable transformation method using Agrobacterium rhizogenes for hairy root transformation and regenerati...

Duplicated genes are thought to follow one of three evolutionary trajectories that resolve their redundancy: neofunctionalization, subfunctionalization or pseudogenization. Differences in expression patterns have been documented for many duplicated gene pairs and interpreted as evidence of subfunctionalization and a loss of redundancy. However, lit...

Establishment of final leaf size in plants relies on the precise regulation of two interconnected processes, cell division and cell expansion. The barley (Hordeum vulgare) protein BROAD LEAF1 (BLF1) limits cell proliferation and leaf growth in the width direction. However, how the levels of this potent repressor of leaf growth are controlled remain...

Flowering plants exhibit a wide range of sexual reproduction systems, with the majority being hermaphroditic. However, some plants, such as Actinidia arguta (kiwiberry), have evolved into dioecious species with distinct female and male vines. In this study, we investigated the flower load and growth habits of female kiwiberry genotypes to identify...

In dioecious crops such as Actinidia arguta (kiwiberries), some of the main challenges when breeding for fruit characteristics are the selection of potential male parents and the long juvenile period. Currently, breeding values of male parents are estimated through progeny tests, which makes the breeding of new kiwiberry cultivars time-consuming an...

Canopy architecture in cereals plays an important role in determining yield. The width of leaves represents one key aspect of this canopy architecture. However, our understanding of leaf width control in cereals remains incomplete. Classical mutagenesis studies in barely identified multiple morphological mutants, including those with differing leaf...

Premise of the study: Floral scent, usually consisting of multiple compounds, is a complex trait and its role in pollinator attraction has received increasing attention. However, it is difficult to disentangle the effect of individual floral scent compounds due to the complexity of isolating the effect of single compounds by traditional methods....

Background Transcriptional regulation is a key aspect of environmental stress responses. Heat stress induces transcriptional memory, i.e., sustained induction or enhanced re-induction of transcription, that allows plants to respond more efficiently to a recurrent HS. In light of more frequent temperature extremes due to climate change, improving he...

In dioecious crops such as Actinidia arguta (kiwiberries), some of the main challenges when breeding for fruit characteristics is the selection of potential male parents and the long juvenile period. Currently, breeding values of male parents are estimated through progeny tests, which makes the breeding of new kiwiberry cultivars time-consuming and...

[This corrects the article DOI: 10.1371/journal.pgen.1008873.].

Self-incompatibility is one of the mechanisms preventing inbreeding in populations, based on the failure of pollen grains to germinate or of pollen tubes to grow normally in incompatible crosses. A unique model for studying this process are heterostylous species, in which self-incompatibility alleles are closely linked to flower morphological trait...

In a recent issue of Nature, Huang et al. identify and show how to overcome the barriers to successful pollen germination after interspecific crosses.1 Their findings answer a long-standing question about reproductive barriers in flowering plants and open the door to harnessing genetic diversity of distant relatives for crop improvement.

Polyadenylation of mRNAs is critical for their export from the nucleus, stability and efficient translation. The Arabidopsis thaliana genome encodes three isoforms of canonical nuclear poly(A) polymerase (PAPS) that redundantly polyadenylate the bulk of pre-mRNAs. However, previous studies have indicated that subsets of pre-mRNAs are preferentially...

The study of the independent evolution of similar characters can highlight important ecological and genetic factors that drive phenotypic evolution. The transition from reproduction by outcrossing to self-fertilization has occurred frequently throughout plant evolution. A common trend in this transition is the reduction of flower features in the se...

Supergenes are non-recombining genomic regions ensuring the co-inheritance of multiple, co-adapted 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, heterosty...

Most flowering plants are hermaphrodites, with flowers having both male and female reproductive organs. One widespread adaptation to limit self-fertilization is self-incompatibility (SI), where self-pollen fails to fertilize ovules.¹,² In homomorphic SI, many morphologically indistinguishable mating types are found, although in heteromorphic SI, th...

To predict how widely distributed species will perform under future climate change, it is crucial to understand and reveal their underlying phylogenetics. However, detailed information about plant adaptation and its genetic basis and history remains scarce and especially widely distributed species receive little attention despite their putatively h...

To predict how widely distributed species will perform under future climate change, it is crucial to understand and reveal their underlying phylogenetics. However, detailed information about plant adaptation and its genetic basis and history remains scarce and especially widely distributed species receive little attention despite their putatively h...

KLU, encoded by a cytochrome P450 CYP78A family gene, generates an important—albeit unknown—mobile signal that is distinct from the classical phytohormones. Multiple lines of evidence suggest that KLU/KLU-dependent signaling functions in several vital developmental programs, including leaf initiation, leaf/floral organ growth, and megasporocyte cel...

Fairy circles are striking regularly sized and spaced, bare circles surrounded by Stipagrostis grasses that occur over thousands of square kilometres in Namibia. The mechanisms explaining their origin, shape, persistence and regularity remain controversial. One hypothesis for the formation of vegetation rings is based on the centrifugal expansion o...

Significance Heterostyly is an adaptation to promote outbreeding in plants. In heterostylous primroses, plants form flowers either with long styles and low anthers or with short styles and high anthers. This difference is due to a chromosomal segment containing five predicted genes, yet their roles and the evolution of this segment remain unclear....

The shoot meristem, a stem-cell-containing tissue initiated during plant embryogenesis, is responsible for continuous shoot organ production in postembryonic development. Although key regulatory factors including KNOX genes are responsible for stem cell maintenance in the shoot meristem, how the onset of such factors is regulated during embryogenes...

The regulation of leaf size has been studied for decades. Enhancement of post-mitotic cell expansion triggered by impaired cell proliferation in Arabidopsis is an important process for leaf size regulation, and is known as compensation. This suggests a key interaction between cell proliferation and cell expansion during leaf development. Several st...

The number of male gametes is critical for reproductive success and varies between and within species. The evolutionary reduction of the number of pollen grains encompassing the male gametes is widespread in selfing plants. Here, we employ genome-wide association study (GWAS) to identify underlying loci and to assess the molecular signatures of sel...

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...

This article comments on: Gattolin, S, Cirilli M, Chessa S, et al. 2020. Mutations in orthologous PETALOSA TOE-type genes cause dominant double-flower phenotype in phylogenetically distant eudicots. Journal of Experimental Botany 71, 2585–2595.

Induced point mutations are important genetic resources for their ability to create hypo- and hypermorphic alleles that are useful for understanding gene functions and breeding. However, such mutant populations have only been developed for a few temperate maize varieties, mainly B73 and W22, yet no tropical maize inbred lines have been mutagenized...

The transition from pollinator‐mediated outbreeding to selfing has occurred many times in angiosperms. This is generally accompanied by a reduction in traits attracting pollinators, including reduced emission of floral scent. In Capsella, emission of benzaldehyde as a main component of floral scent has been lost in selfing C. rubella by mutation of...

In self-incompatible plants the female style rejects self pollen, yet the extent to which the female style in the many self-compatible species can still select between different pollen genotypes and thus bias fertilization success is unclear. A new study identifies the molecular basis for how styles of the self-compatible coyote tobacco bias the fe...

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 PCR-genotyping individual offspring of focal plants for multiple polymorphic markers is laborious and time-consuming. Results We...

RNA‐based processes play key roles in the regulation of eukaryotic gene expression. This includes both the processing of pre‐mRNAs into mature mRNAs ready for translation and RNA‐based silencing processes, such as RNA‐directed DNA methylation (RdDM). Polyadenylation of pre‐mRNAs is one important step in their processing and is carried out by three...

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 ex...

Capsella species, including the well-known Shephard's purse, are characterized by small white flowers and heart-shaped fruit. But read on to discover the fascinating insights these diminutive plants have to reveal about the evolution of self-fertilizing plants.

The number of male gametes produced is critical for reproductive success and varies greatly between and within species 1–3 . Evolutionary reduction of male gamete production has been widely reported in plants as a hallmark of the selfing syndrome, as well as in humans. Such a reduction may simply represent deleterious decay 4–7 , but evolutionary t...

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 resp...

The number of male gametes produced is critical for reproductive success and varies greatly between and within species. Evolutionary reduction of male gamete production has been widely reported in plants as a hallmark of the selfing syndrome, as well as in humans. Such a reduction may simply represent deleterious decay, but evolutionary theory pred...

Plant leaves have functionally specialized upper and lower sides. Two recent studies show that these opposite identities are derived from a pre-pattern in the shoot meristem and the border between them is maintained by mobile small RNAs with morphogen-like properties. Plant leaves have functionally specialized upper and lower sides. Two recent stud...

Understanding the molecular basis of morphological change remains a central challenge in evolutionary-developmental biology. The transition from outbreeding to selfing is often associated with a dramatic reduction in reproductive structures and functions, such as the loss of attractive pheromones in hermaphroditic Caenorhabditis elegans and a reduc...

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 fitn...

The enormous species richness of flowering plants is at least partly due to floral diversification driven by interactions between plants and their animal pollinators [1, 2]. Specific pollinator attraction relies on visual and olfactory floral cues [3-5]; floral scent can not only attract pollinators but also attract or repel herbivorous insects [6-...

Significance Flower size can change rapidly in evolution; in particular, the frequent transition from animal-mediated out-crossing to self-pollination is often associated with a dramatic, yet rapid and specific, reduction in flower size. Here we demonstrate that the small petals of the selfing red Shepherd’s Purse ( Capsella rubella ) are because o...

Multiple-sequence alignment of coding sequences of CYP734A family members in MEGA format. DOI: http://dx.doi.org/10.7554/eLife.17956.025

Read counts from Illumina whole-genome sequencing of S- and L-morph plants of P. vulgaris and P. forbesii.Reads were mapped to the exons of CYP734A50 and CYP734A51 including the 200 surrounding intronic nucleotides (± 100 bp). Absolute read counts are given. Due to the very similar target lengths for mapping against both genes, absolute read counts...

Full results of branch-site tests 1 and 2 for relaxed constraints or positive selection.(A) Subtree as in Figure 4 with numbered branches for which branch-site tests were performed. The orange branch shows evidence of relaxed selection; the green branch shows evidence of positive selection. (B) Results of branch-site tests 1 and 2 for the indicated...

Multiple-sequence alignment of protein sequences of CYP734A family members in MEGA format. DOI: http://dx.doi.org/10.7554/eLife.17956.027

Candidates for S-morph style-specific genes.TPM values and annotations are indicated for candidate transcripts showing significantly (p<0.05) higher expression in S-morph styles than in S-morph corolla tubes and in either L-morph styles or corolla tubes.DOI: http://dx.doi.org/10.7554/eLife.17956.004

Oligonucleotide sequences used. DOI: http://dx.doi.org/10.7554/eLife.17956.023

Coding sequences of CYP734A family members from sequenced genomes in fasta format. DOI: http://dx.doi.org/10.7554/eLife.17956.024

Protein sequences of CYP734A family members from sequenced genomes in fasta format. DOI: http://dx.doi.org/10.7554/eLife.17956.026

Comparison of synonymous and non-synonymous substitution rates between CYP734A50 and CYP734A51 genes.Results of Ka and Ks calculations for CYP734A50 and CYP734A51 genes using the Nei-Gojobori method with complete deletion of missing data. Ka and Ks rates were compared using Fisher’s exact test.DOI: http://dx.doi.org/10.7554/eLife.17956.019

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 hear...

ELife digest Flowers are highly specialized structures that many plants use to reproduce. Male organs called stamens on the flowers make pollen that can be transferred – usually by insect carriers or the wind – to a female structure called the stigma on another plant. However, since many flowers contain both male and female organs, it is also possi...

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 differen...

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 an...

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 th...

To achieve optimal functionality, plant organs like leaves and petals have to grow to a certain size. Beginning with a limited number of undifferentiated cells, the final size of an organ is attained by a complex interplay of cell proliferation and subsequent cell expansion. Regulatory mechanisms that integrate intrinsic growth signals and environm...

The poly(A) tail at 3' ends of eukaryotic mRNAs promotes their nuclear export, stability and translational efficiency, and changes in its length can strongly impact gene expression. The Arabidopsis thaliana genome encodes three canonical nuclear poly(A) polymerases, PAPS1, PAPS2 and PAPS4. As shown by their different mutant phenotypes, these three...

Mitogen-activated dual-specificity MAPK phosphatases are important negative regulators in the MAPK signalling pathways responsible for many essential processes in plants. In a screen for mutants with reduced organ size we have identified a mutation in the active site of the dual-specificity MAPK phosphatase INDOLE-3-BUTYRIC ACID-RESPONSE5 (IBR5) th...

Mitogen-activated dual-specificity MAPK phosphatases are important negative regulators in the MAPK signalling pathways responsible for many essential processes in plants. In a screen for mutants with reduced organ size we have identified a mutation in the active site of the dual-specificity MAPK phosphatase INDOLE-3-BUTYRIC ACID-RESPONSE5 (IBR5) th...

Author Summary Most of the visible growth of plant organs is driven by cell expansion without associated cell division. As plant cells are encased in cell walls, expansion requires the controlled loosening of the existing cell wall and synthesis of additional wall material. While a number of factors and plant hormones are known that promote cell ex...

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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,...

Polyadenylation of pre-mRNAs by poly(A) polymerase (PAPS) is a critical process in eukaryotic gene expression. Like 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...

Phyllotaxis and vein formation are among the most conspicuous patterning processes in plants. The expression and polarization of the auxin efflux carrier PIN1 is the earliest marker for both processes, with mathematical models indicating that PIN1 can respond to auxin gradients and/or auxin flux. Here, we use cell-layer-specific PIN1 knockouts and...

In yeast, cell growth and division are coordinated by size checkpoints in the cell cycle. Recent work suggests that a similar mechanism acts in plant meristems to limit cell-size variation.

In recent years, an increasing number of mutations in what would appear to be 'housekeeping genes' have been identified as having unexpectedly specific defects in multicellular organogenesis. This is also the case for organogenesis in seed plants. Although it is not surprising that loss-of-function mutations in 'housekeeping' genes result in lethal...

The size of plant organs, such as leaves and flowers, is determined by an interaction of genotype and environmental influences. Organ growth occurs through the two successive processes of cell proliferation followed by cell expansion. A number of genes influencing either or both of these processes and thus contributing to the control of final organ...