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Lüth VM, Rempfer C, van Gessel N, Herzog O, Hanser M, Braun M, Decker EL, Reski R. A Physcomitrella PIN protein acts in spermatogenesis and sporophyte retention. THE NEW PHYTOLOGIST 2023; 237:2118-2135. [PMID: 36696950 DOI: 10.1111/nph.18691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
The auxin efflux PIN-FORMED (PIN) proteins are conserved in all land plants and important players in plant development. In the moss Physcomitrella (Physcomitrium patens), three canonical PINs (PpPINA-C) are expressed in the leafy shoot (gametophore). PpPINA and PpPINB show functional activity in vegetative growth and sporophyte development. Here, we examined the role of PpPINC in the life cycle of Physcomitrella. We established reporter and knockout lines for PpPINC and analysed vegetative and reproductive tissues using microscopy and transcriptomic sequencing of moss gametangia. PpPINC is expressed in immature leaves, mature gametangia and during sporophyte development. The sperm cells (spermatozoids) of pinC knockout mutants exhibit increased motility and an altered flagella phenotype. Furthermore, the pinC mutants have a higher portion of differentially expressed genes related to spermatogenesis, increased fertility and an increased abortion rate of premeiotic sporophytes. Here, we show that PpPINC is important for spermatogenesis and sporophyte retention. We propose an evolutionary conserved way of polar growth during early moss embryo development and sporophyte attachment to the gametophore while suggesting the mechanical function in sporophyte retention of a ring structure, the Lorch ring.
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Affiliation(s)
- Volker M Lüth
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Christine Rempfer
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104, Freiburg, Germany
| | - Nico van Gessel
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Oliver Herzog
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Melanie Hanser
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Marion Braun
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Eva L Decker
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Ralf Reski
- Plant Biotechnology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104, Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
- Cluster of Excellence livMatS @ FIT - Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg, 79110, Freiburg, Germany
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Lang AS, Gehrmann T, Cronberg N. Genetic Diversity and Population Structure in Bryophyte With Facultative Nannandry. FRONTIERS IN PLANT SCIENCE 2021; 12:517547. [PMID: 33897717 PMCID: PMC8059434 DOI: 10.3389/fpls.2021.517547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
Among plants, gender dimorphism occurs in about 10% of all angiosperms and more than 50% of all moss taxa, with dwarf males (DM) found exclusively in some unisexual mosses. In this study, we explore the role of male dwarfism as a reproductive strategy in the widespread acrocarpous moss Dicranum scoparium, which has facultative male dwarfism, having both dwarf males (DMs) and normal-sized males (NMs). We retrieved 119 SNP markers from transcriptomes which were used to genotype 403 samples from 11 sites at seven localities in southern Sweden. Our aims were to compare the genetic variability and genetic structure of sexually reproducing populations at different geographic levels (cushion, site, and locality) and compare in particular the relative contribution of females, dwarf males and normal-sized males to the observed genetic diversity. The numbers of DMs differed strongly between sites, but when present, they usually outnumbered both females and NMs. Low genetic differentiation was found at locality level. Genetic differentiation was strongest between cushions for females and NMs and within cushions for DMs indicating small scale structuring and sometimes inbreeding. NMs were more clonal than either DMs or females. Genetic diversity was similar between females and DMs, but lower for NMs. Two haplotypes were shared between females and DMs and one haplotype was shared between a DM and a NM. In conclusion, our results show that DMs and NMs play different roles in reproduction, inbreeding may occur at cushion level, but gene flow is high enough to prevent substantial genetic drift.
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Affiliation(s)
| | - Thies Gehrmann
- Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands
| | - Nils Cronberg
- Department of Biology, Lund University, Lund, Sweden
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Krueger-Hadfield SA, Guillemin ML, Destombe C, Valero M, Stoeckel S. Exploring the Genetic Consequences of Clonality in Haplodiplontic Taxa. J Hered 2021; 112:92-107. [PMID: 33511982 DOI: 10.1093/jhered/esaa063] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 12/18/2020] [Indexed: 11/15/2022] Open
Abstract
Partially clonality is an incredibly common reproductive mode found across all the major eukaryotic lineages. Yet, population genetic theory is based on exclusive sexuality or exclusive asexuality, and partial clonality is often ignored. This is particularly true in haplodiplontic eukaryotes, including algae, ferns, mosses, and fungi, where somatic development occurs in both the haploid and diploid stages. Haplodiplontic life cycles are predicted to be correlated with asexuality, but tests of this prediction are rare. Moreover, there are unique consequences of having long-lived haploid and diploid stages in the same life cycle. For example, clonal processes uncouple the life cycle such that the repetition of the diploid stage via clonality leads to the loss of the haploid stage. Here, we surveyed the literature to find studies that had genotyped both haploid and diploid stages and recalculated population genetic summary metrics for seven red algae, one green alga, three brown algae, and three mosses. We compared these data to recent simulations that explicitly addressed the population genetic consequences of partial clonality in haplodiplontic life cycles. Not only was partial clonality found to act as a homogenizing force, but the combined effects of proportion of haploids, rate of clonality, and the relative strength of mutation versus genetic drift impacts the distributions of population genetic indices. We found remarkably similar patterns across commonly used population genetic metrics between our empirical and recent theoretical expectations. To facilitate future studies, we provide some recommendations for sampling and analyzing population genetic parameters for haplodiplontic taxa.
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Affiliation(s)
| | - Marie-Laure Guillemin
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Universités, Pontificia Universidad Católica de Chile, Universidad Austral de Chile, IRL 3614, Station Biologique de Roscoff, Roscoff, France
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Casilla, Valdivia, Chile
| | - Christophe Destombe
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Universités, Pontificia Universidad Católica de Chile, Universidad Austral de Chile, IRL 3614, Station Biologique de Roscoff, Roscoff, France
| | - Myriam Valero
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Universités, Pontificia Universidad Católica de Chile, Universidad Austral de Chile, IRL 3614, Station Biologique de Roscoff, Roscoff, France
| | - Solenn Stoeckel
- INRAE, Agrocampus Ouest, Université de Rennes, IGEPP, Le Rheu, France
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Sawangproh W, Lang AS, Hedenäs L, Cronberg N. Morphological characters and SNP markers suggest hybridization and introgression in sympatric populations of the pleurocarpous mosses Homalothecium lutescens and H. sericeum. ORG DIVERS EVOL 2020. [DOI: 10.1007/s13127-020-00456-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AbstractHybridization in bryophytes involves a fusion of gametes produced by haploid parental gametophytes of different species. The primary hybrid is thus the short-lived diploid sporophyte, which soon undergoes meiosis prior to the formation of large amounts of haploid spores. We compared morphology of gametophytes (branch leaves) and sporophytes (capsule inclination) from sympatric populations and allopatric populations of H. lutescens and H. sericeum. In addition, we used transcriptome data to select 85 nuclear SNP markers that were fixed for alternative alleles in the two species. The SNPs were used to estimate the degree of hybridization in diploid sporophytes. Our study shows that gametophytes from sympatric populations display intermediate morphology in a number of leaf characters, with exception for leaf sizes, which are markedly smaller than those in allopatric populations. None of the 100 sporophytes appeared to be primary hybrids, but 33 displayed admixing—heterozygotic expression of SNP markers or mismatch of occasional markers in homozygous condition—suggesting that extensive introgression takes place in the sympatric populations. Most sporophytes with intermediate capsule inclination, initially classed as putative hybrids, did not display admixture of nuclear SNP markers. Sixty-seven percent of admixed sporophytes have predominantly nuclear SNPs typical for H. lutescens. Our results suggest that interspecific hybridization and bidirectional introgression are relatively common in the studied sympatric populations, giving rise to viable recombinants, but not complete mixing of the parental genomes. Our study is one of the first detailed accounts of hybridization among pleurocarpous mosses, opening for future studies of gene transfer and introgression between bryophyte lineages and its role in local adaptation and long-term evolutionary diversification.
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Sawangproh W, Hedenäs L, Lang AS, Hansson B, Cronberg N. Gene transfer across species boundaries in bryophytes: evidence from major life cycle stages in Homalothecium lutescens and H. sericeum. ANNALS OF BOTANY 2020; 125:565-579. [PMID: 31872857 PMCID: PMC7102947 DOI: 10.1093/aob/mcz209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 12/20/2019] [Indexed: 05/14/2023]
Abstract
BACKGROUND AND AIMS The mosses Homalothecium lutescens and H. sericeum are genetically, morphologically and ecologically differentiated; mixed populations sometimes occur. In sympatric populations, intermediate character states among gametophytes and sporophytes have been observed, suggesting hybridization and introgression in such populations. METHODS We determined genotypes using bi-allelic co-dominant single nucleotide polymorphism (SNP) markers, specific to either H. lutescens or H. sericeum, to estimate the degree of genetic mixing in 449 moss samples collected from seven sympatric and five allopatric populations on the island of Öland, south Sweden. The samples represented three generations: haploid maternal gametophytes; diploid sporophytes; and haploid sporelings. KEY RESULTS Admixture analyses of SNP genotypes identified a majority as pure H. lutescens or H. sericeum, but 76 samples were identified as mildly admixed (17 %) and 17 samples (3.8 %) as strongly admixed. Admixed samples were represented in all three generations in several populations. Hybridization and introgression were bidirectional. CONCLUSIONS Our results demonstrate that admixed genomes are transferred between the generations, so that the populations behave as true hybrid zones. Earlier studies of sympatric bryophyte populations with admixed individuals have not been able to show that admixed alleles are transferred beyond the first generation. The presence of true hybrid zones has strong evolutionary implications because genetic material transferred across species boundaries can be directly exposed to selection in the long-lived haploid generation of the bryophyte life cycle, and contribute to local adaptation, long-term survival and speciation.
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Affiliation(s)
- W Sawangproh
- Biodiversity, Department of Biology, Lund University, Lund, Sweden
- Division of Conservation Biology, School of Interdisciplinary Studies, Mahidol University (Kanchanaburi Campus), Kanchanaburi Province, Thailand
| | - L Hedenäs
- Department of Botany, Swedish Museum of Natural History, Stockholm, Sweden
| | - A S Lang
- Biodiversity, Department of Biology, Lund University, Lund, Sweden
| | - B Hansson
- Department of Biology, Lund University, Lund, Sweden
| | - N Cronberg
- Biodiversity, Department of Biology, Lund University, Lund, Sweden
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Haig D. Living together and living apart: the sexual lives of bryophytes. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0535. [PMID: 27619699 DOI: 10.1098/rstb.2015.0535] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2016] [Indexed: 01/08/2023] Open
Abstract
Haploid gametophytes of bryophytes spread by clonal growth but mate locally, within an area defined by the range of sperm movement. Rarity of establishment from spores or vegetative competition can result in unisexual populations unable to reproduce sexually. Females typically outcompete males, probably because females expend fewer resources than males on the production of gametes. Extreme sexual dimorphism-tiny males growing as epiphytes on much larger females-has evolved many times. Haploid selfing is common in bryophytes with bisexual gametophytes, and results in completely homozygous sporophytes. Spores from these sporophytes recapitulate the genotype of their single haploid parent. This process can be considered analogous to 'asexual' reproduction with 'sexual' reproduction occurring after rare outcrossing between haploid parents. Ferns also produce bisexual haploid gametophytes but, unlike bryophytes, haploid outcrossing predominates over haploid selfing. This difference is probably related to clonal growth and vegetative competition occurring in the haploid but not the diploid phase in bryophytes, but the reverse in ferns. Ferns are thereby subject to stronger inbreeding depression than bryophytes.This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'.
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Affiliation(s)
- David Haig
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA
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Baughman JT, Payton AC, Paasch AE, Fisher KM, McDaniel SF. Multiple factors influence population sex ratios in the Mojave Desert moss Syntrichia caninervis. AMERICAN JOURNAL OF BOTANY 2017; 104:733-742. [PMID: 28490519 DOI: 10.3732/ajb.1700045] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/27/2017] [Indexed: 06/07/2023]
Abstract
PREMISE OF RESEARCH Natural populations of many mosses appear highly female-biased based on the presence of reproductive structures. This bias could be caused by increased male mortality, lower male growth rate, or a higher threshold for achieving sexual maturity in males. Here we test these hypotheses using samples from two populations of the Mojave Desert moss Syntrichia caninervis. METHODS We used double-digest restriction-site associated DNA (RAD) sequencing to identify candidate sex-associated loci in a panel of sex-expressing plants. Next, we used putative sex-associated markers to identify the sex of individuals without sex structures. KEY RESULTS We found a 17:1 patch-level phenotypic female to male sex ratio in the higher elevation site (Wrightwood) and no sex expression at the low elevation site (Phelan). In contrast, on the basis of genetic data, we found a 2:1 female bias at the Wrightwood site and only females at the Phelan site. The relative area occupied by male and female genets was indistinguishable, but males were less genetically diverse. CONCLUSIONS Our data suggest that both male-biased mortality and sexual dimorphism in thresholds for sex expression could explain genetic and phenotypic sex ratio biases and that phenotypic sex expression alone over-estimates the extent of actual sex ratio bias present in these two populations of S. caninervis.
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Affiliation(s)
- Jenna T Baughman
- Department of Biological Sciences, California State University, 5151 State University Drive, Los Angeles, California 90032 USA
| | - Adam C Payton
- Department of Biology, University of Florida, 876 Newell Drive, Gainesville, Florida 32611 USA
| | - Amber E Paasch
- Department of Biological Sciences, California State University, 5151 State University Drive, Los Angeles, California 90032 USA
| | - Kirsten M Fisher
- Department of Biological Sciences, California State University, 5151 State University Drive, Los Angeles, California 90032 USA
| | - Stuart F McDaniel
- Department of Biology, University of Florida, 876 Newell Drive, Gainesville, Florida 32611 USA
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Rosengren F, Hansson B, Cronberg N. Population structure and genetic diversity in the nannandrous moss Homalothecium lutescens: does the dwarf male system facilitate gene flow? BMC Evol Biol 2015; 15:270. [PMID: 26634921 PMCID: PMC4669626 DOI: 10.1186/s12862-015-0545-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 11/17/2015] [Indexed: 11/22/2022] Open
Abstract
Background Nannandry is a sexual system where males (”dwarf males”) are much smaller than the conspecific females. Dwarf males occur in a wide range of unrelated organisms but the evolutionary advantages of this condition are poorly understood. The dwarf male sexual system results in differences in the mode of dispersal and establishment as well as the life span between males and females. Such differences must have profound effects on the population dynamics and genetic structures. We have studied four populations of the nannandrous moss Homalothecium lutescens in southern Sweden. We genotyped dwarf males and female shoots with the aim of describing the genetic diversity and structure of the populations. Results Dwarf males were most related to their host shoot, then their colony (within 0.5 m2) and then the rest of the population, which suggests restricted spore dispersal. However, a few dwarf males in each population appeared to originate from other colonies and sometimes even other populations. Genetic diversity of dwarf males was generally high but showed no tendency to be consistently higher or lower than female genetic diversity within the four populations. Conclusions Although most dwarf males have local origin, sporadic dispersal events occur. The ability of the dwarf males to establish in high numbers in mature colonies facilitates gene flow between populations as well as increases the potential to accumulate genetic diversity within populations.
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Affiliation(s)
- Frida Rosengren
- Department of Biology, Biodiversity, Lund University, Ecology Building, SE-223 62, Lund, Sweden.
| | - Bengt Hansson
- Department of Biology, Lund University, Molecular Ecology and Evolution Lab, Ecology Building, SE-223 62, Lund, Sweden.
| | - Nils Cronberg
- Department of Biology, Biodiversity, Lund University, Ecology Building, SE-223 62, Lund, Sweden.
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