Liverwort Marchantia Research Articles

Synthesis and signalling of strigolactone and KAI2-ligand signals in bryophytes.

Strigolactones (SLs), long known as butenolide rhizospheric signals, have been recognized since 2008 as a class of hormones regulating many aspects of plant development. Many authors also anticipate 'KAI2-ligand' (KL) as a novel class of phytohormones; however, this ligand remains elusive. Core genes of SL and KL pathways, first described in angiosperms, are found in all land plants and some even in green algae. This review reports current knowledge of these pathways in bryophytes. Data on the pathways mostly come from two models: the moss Physcomitrium patens and the liverwort Marchantia. Gene targeting methods have allowed functional analyses of both models. Recent work in Marchantia suggests that SLs' ancestral role was to recruit beneficial microbes as arbuscular mycorrhizal fungi. In contrast, the hormonal role of SLs observed in P. patens is probably a result of convergent evolution. Evidence for a functional KL pathway in both bryophyte models is very recent. Nevertheless, many unknowns remain and warrant a more extensive investigation of SL and KL pathways in various land plant lineages.

KANADI promotes thallus differentiation and FR-induced gametangiophore formation in the liverwort Marchantia.

Summary In angiosperms, KANADI transcription factors have roles in the sporophyte generation regulating tissue polarity, organogenesis and shade avoidance responses, but are not required during the gametophyte generation. Whether these roles are conserved in the gametophyte‐dominant bryophyte lineages is unknown, which we examined by characterising the sole KANADI ortholog, MpKAN, in the liverwort Marchantia polymorpha.In contrast to angiosperm orthologs, MpKAN functions in the gametophyte generation in Marchantia, where it regulates apical branching and tissue differentiation, but does not influence tissue polarity in either generation. MpKAN can partially rescue the sporophyte polarity defects of kanadi mutants in Arabidopsis, indicating that MpKAN has conserved biochemical activity to its angiosperm counterparts.Mpkan loss‐of‐function plants display defects in far‐red (FR) light responses. Mpkan plants have reduced FR‐induced growth tropisms, have a delayed transition to sexual reproduction and fail to correctly form gametangiophores.Our results indicate that MpKAN is a modulator of FR responses, which may reflect a conserved role for KANADI across land plants. Under FR, MpKAN negatively regulates MpDELLA expression, suggesting that MpKAN and MpDELLA act in a pathway regulating FR responses, placing MpKAN in a gene regulatory network exhibiting similarities with those of angiosperms.

Plant sex chromosomes defy evolutionary models of expanding recombination suppression and genetic degeneration.

Hundreds of land plant lineages have independently evolved separate sexes in either gametophytes (dioicy) or sporophytes (dioecy), but 43% of all dioecious angiosperms are found in just 34 entirely dioecious clades, suggesting that their mode of sex determination evolved a long time ago. Here, we review recent insights on the molecular mechanisms that underlie the evolutionary change from individuals that each produce male and female gametes to individuals specializing in the production of just one type of gamete. The canonical model of sex chromosome evolution in plants predicts that two sex-determining genes will become linked in a sex-determining region (SDR), followed by expanding recombination suppression, chromosome differentiation and, ultimately, degeneration. Experimental work, however, is showing that single genes function as master regulators in model systems, such as the liverwort Marchantia and the angiosperms Diospyros and Populus. In Populus, this type of regulatory function has been demonstrated by genome editing. In other systems, including Actinidia, Asparagus and Vitis, two coinherited factors appear to independently regulate female and male function, yet sex chromosome differentiation has remained low. We discuss the best-understood systems and evolutionary pathways to dioecy, and present a meta-analysis of the sizes and ages of SDRs. We propose that limited sexual conflict explains why most SDRs are small and sex chromosomes remain homomorphic. It appears that models of increasing recombination suppression with age do not apply because selection favours mechanisms in which sex determination depends on minimal differences, keeping it surgically precise.

Control of liverwort (Marchantia polymorpha L.) growth in nursery plants with mulches of Sphagnum moss and blackcurrant stem pieces

Liverwort (Marchantia polymorpha L.) is a problematic weed on container surfaces in nurseries, because it hampers water and nutrient access to growing plants. No chemical herbicide against it is available in the EU. Mulches are the most common non-chemical weed control method. Mulches of Sphagnum moss and 1-cm blackcurrant stem pieces were used. Mulches’ effect on liverwort control continued for two years on highbush blueberry and blackcurrant, and one year on rhododendron. The blackcurrant stem pieces trial continued for one year. Blueberry and rhododendron demand acidic growing media, creating an acute need for liverwort control. Sieved moss was used in two different layers on top of a pot. The prevention rate of liverwort growth in blueberry in July–August was 95–99%, and in October 78–90%, depending on weather conditions; in rhododendron and blackcurrant, it was 90–95%. The control effect was diminished in more decomposed moss. No significant difference between thickness and coarseness of moss mulch layers was observed. Blackcurrant stem pieces controlled liverwort growth by almost 100%.

Plant-inspired pipettes.

The female sex organ of the liverwort (Marchantia polymorpha) has a characteristic parasol-like form highly suitable for collecting water droplets containing sperm for fertilization. Motivated by this observation and using three-dimensional printing techniques, we develop a parasol-like rigid object that can grab, transport and release water droplets of a maximum size of about 1 cm. By combining experiments and scaling theory, we quantify the object's fundamental wetting and fluid dynamical properties. We construct a stability phase diagram and suggest that it is largely insensitive to properties of liquids such as surface tension and viscosity. A simple scaling argument is developed to explain the phase boundary. Our study provides basic design rules of a simple pipette-like device with bubble-free capture and drop of liquids, which can be used in laboratory settings and has applications within soft robotics. Through systematic experimental investigations, we suggest the optimal design criteria of the liverwort-inspired object to achieve maximal pipetting performance. We also provide, based on our scalable model experiments, a biological implication for the mechanistic advantage of this structure in liverwort reproduction.

Direction of illumination controls gametophyte orientation in seedless plants and related algae

The environmental influences that determine dorsiventral or axial gametophyte orientation are unknown for most modern seedless plants. To fill this gap, an experimental laboratory system was employed to evaluate the relative effects of light direction and gravity on body orientation of the dorsiventral green alga Coleochaete orbicularis, and gametophytes of liverworts Blasia pusilla and Marchantia polymorpha, early-diverging moss Sphagnum compactum, and fern Ceratopteris richardii, the latter functioning as experimental control. Replicate clonal cultures were experimentally illuminated only from above, only from below, or from multiple directions, with the same near-saturation PAR level for periods brief enough to minimize nutrient limitation effects, and orientation of new growth was evaluated. For all species tested, direction of illumination exerted stronger control over gametophyte body orientation than gravity. When illuminated only from below: 1) axial Sphagnum gametophores that had initially grown into an overlying air space inverted growth by 180°, burrowing into the substrate; 2) new growth of dorsiventral Blasia, Marchantia, and Ceratopteris gametophytes–whose ventral rhizoids initially penetrated agar substrate and dorsal surfaces initially faced overlying airspace–twisted 180° so that ventral surfaces bearing rhizoids faced overlying air space and rhizoids extended into the air; and 3) Coleochaete lost typical dorsiventral organization and diagnostic dorsal hairs. Direction of illumination also exerted stronger control over orientation of liverwort new growth than surface contact did. These results indicate that early land plants likely inherited light-directed gametophyte body orientation from ancestral streptophyte algae and suggest a mechanism for reorientation of gametophyte-dominant land plants after spatial disturbance.

Interpreting bryophyte stable carbon isotope composition: Plants as temporal and spatial climate recorders

Bryophytes are unable to control tissue water content although physiological adaptations allow growth in a wide range of habitats. Carbon isotope signals in two mosses (Syntrichia ruralis and Chorisodontium aciphyllum) and two liverworts (Conocephalum conicum and Marchantia polymorpha), whether instantaneous (real time, Δ13C), or organic matter (as δ13COM), provide an assimilation-weighted summary of bryophyte environmental adaptations. In mosses, δ13COM is within the measured range of Δ13C values, which suggests that other proxies, such as compound-specific organic signals, will be representative of historical photosynthetic and growth conditions. The liverworts were photosynthetically active over a wider range of relative water contents (RWC) than the mosses. There was a consistent 5‰ offset between Δ13C values in C. conicum and M. polymorpha, suggestive of greater diffusion limitation in the latter. Analysis of a C. aciphyllum moss-peat core showed the isotopic composition over the past 200 years reflects recent anthropogenic CO2 emissions. Once corrected for source-CO2 inputs, the seasonally integrated Δ13COM between 1350 and 2000 A.D. varied by 1.5‰ compared with potential range of the 12‰ measured experimentally, demonstrating the relatively narrow range of conditions under which the majority of net assimilation takes place. Carbon isotope discrimination also varies spatially, with a 4‰ shift in epiphytic bryophyte organic matter found between lowland Amazonia and upper montane tropical cloud forest in the Peruvian Andes, associated with increased diffusion limitation.

Simple sequence repeats in bryophyte mitochondrial genomes

Simple sequence repeats (SSRs) are thought to be common in plant mitochondrial (mt) genomes, but have yet to be fully described for bryophytes. We screened the mt genomes of two liverworts (Marchantia polymorpha and Pleurozia purpurea), two mosses (Physcomitrella patens and Anomodon rugelii) and two hornworts (Phaeoceros laevis and Nothoceros aenigmaticus), and detected 475 SSRs. Some SSRs are found conserved during the evolution, among which except one exists in both liverworts and mosses, all others are shared only by the two liverworts, mosses or hornworts. SSRs are known as DNA tracts having high mutation rates; however, according to our observations, they still can evolve slowly. The conservativeness of these SSRs suggests that they are under strong selection and could play critical roles in maintaining the gene functions.

Strigolactones affect development in primitive plants. The missing link between plants and arbuscular mycorrhizal fungi?

Strigolactones affect development in primitive plants. The missing link between plants and arbuscular mycorrhizal fungi?

The horsetail Equisetum arvense mitochondria share two group I introns with the liverwort Marchantia, acquired a novel group II intron but lost intron-encoded ORFs

We studied the genomic structure and RNA editing of mitochondrial cox1, cox2, cob and atp9 from the horsetail Equisetum arvense, a representative of an old fern lineage. Editing of cox1, cob and atp9 mRNAs occur only by C-to-U transitions. No changes were found in cox2 transcripts constituting one of the rare examples of unedited mitochondrial mRNA in land plants. From three intervening sequences in cox1, cox1i395 and cox1i624 are group IB introns homologous to the Marchantia polymorpha cox1 introns, and cox1i747 is a group IIA intron different to other introns found in plant mtDNA. The group II intron cox2i373 is very similar to other introns found in cox2 from vascular plants. While cob and atp9 have no introns and display the gene structure found in seed plants, various nucleotide substitutions abolish the only potential ORF, a LAGLIDADG endonuclease present in cox1i395. Thus, E. arvense mitochondria conserve two group I introns from non-vascular plants, probably inherited from a common ancestor with liverworts. Analogous to seed plants, E. arvense has no potential mitochondrial splicing factors encoded in these introns. This is the first report concerning the presence of vertically inherited group I introns in vascular plant mitochondria.

Tracing Plant Mitochondrial DNA Evolution: Rearrangements of the Ancient Mitochondrial Gene Cluster trnA-trnT-nad7 in Liverwort Phylogeny

Whereas frequent recombination characterizes flowering plant mitochondrial genomes, some mitochondrial gene arrangements may, in contrast, be conserved between streptophyte algae and early land plant clades (bryophytes). Here we explore the evolutionary fate of the mitochondrial gene arrangement trnA-trnT-nad7, which is conserved among the alga Chara, the moss Physcomitrella, and the liverwort Marchantia, although trnT is inverted in orientation in the latter. Surprisingly, we now find that the Chara-type gene arrangement is generally conserved in mosses, but that trnT is lacking between trnA and nad7 in all simple-thalloid and leafy (jungermanniid) liverworts. The ancient gene continuity trnA-trnT-nad7 is, however, conserved in Blasia, representing the sister lineage to all other complex-thalloid (marchantiid) liverworts. The recombinogenic insertion of short sequence stretches, including nad5 and rps7 pseudogene fragments copied from elsewhere in the liverwort mtDNA, likely mediated a subsequent inversion of trnT and flanking sequences in a basal grade of marchantiid liverworts, which was then followed by an independent secondary loss of trnT in derived marchantiid taxa later in evolution. In contrast to the previously observed extreme degree of coding sequence conservation and the assumed absence of active recombination in Marchantia mtDNA, this now reveals a surprisingly dynamic evolution of marchantiid liverwort mitochondrial genomes.

Enhanced expression of a calcium-dependent protein kinase from the moss Funaria hygrometrica under nutritional starvation.

Among the downstream targets of calcium in plants, calcium-dependent protein kinases (CDPKs) form an interesting class of kinases which are activated by calcium binding. They have been implicated in a diverse array of responses to hormonal and environmental stimuli. In order to dissect the role of CDPKs in the moss Funaria hygrometrica, a polymerase chain reaction (PCR)-based approach was adopted to clone the gene. Using degenerate PCR primers against conserved regions of CDPKs, a 900 bp amplicon was obtained from the genomic DNA of Funaria. Southern hybridization under low stringency conditions indicated the presence of several CDPK related sequences in the Funaria genome. This observation is consistent with reports of multigene families of CDPKs in other plants. The 900 bp fragment was subsequently used to isolate a 2.2 kb partial genomic clone of the CDPK gene from Funaria. The genomic clone encodes an open reading frame (ORF) of 518 amino acids. Interestingly, unlike other CDPK genes from plants, the entire 1.5 kb ORF is not interrupted by introns. The deduced amino acid sequence of the Funaria gene shows extensive homology with CDPKs from higher plants, 73% identity with the Fragaria CDPK and 71% identity with CDPK isoform 7 of Arabidopsis. Phylogenetic analysis revealed that the Funaria CDPK is closer to the CDPKs from higher plants like strawberry and Arabidopsis as compared to those from lower plants such as the liverwort Marchantia, the green alga Chlamydomonas or another moss Tortula. Northern analysis shows enhanced expression of the CDPK transcript within 24-48 h of starvation for nitrogen, phosphorus or sulphur. So far the only other kinase which is known to be induced by nutrient starvation in plants is the wpk 4 which is a snf-1 related kinase (SnRKs). To our knowledge this is the first report that implicates a CDPK in the starvation response.

Genes for the ribosomal S4 protein encoded in higher plant mitochondria are transcribed, edited, and translated.

Here we describe the structure and expression of the mitochondrial gene that encodes the S4 subunit of the mitochondrial ribosome (rps4) in two higher plants, rapeseed and rice. The ORFs of rapeseed and rice rps4 genes are 362 and 352 codons long, respectively, and their corresponding transcripts are edited (C-to-U conversions) in 19 and 15 positions, respectively. The amino acid sequences deduced from the sequences of the two rps4 genes are 78.1% identical to each other and show about 50% identity to the liverwort (Marchantia polymorpha) mitochondrial RPS4 polypeptide. Both higher plant mitochondrial genes have an inserted sequence (of 137 and 141 codons for rapeseed and rice, respectively) relative to the liverwort rps4 gene. In rice rps4, the 3' portion of the inserted sequence can potentially form two stem-loop structures that resemble two domains characteristic of group II introns, i.e., domains V and VI. However, RT-PCR analysis showed that these sequences were not spliced out during maturation of the rps4 transcripts. Antibodies specific for the plant RPS4 proteins were prepared. Protein blot analysis revealed that RPS4 polypeptides are present in both rapeseed and rice mitochondria, whose sizes are in agreement with the molecular weights calculated from the non-spliced sequences. The rps4 genes and RPS4 polypeptides have been also identified in the mitochondria of wheat, maize, soybean, and turnip by Southern and Western analyses, respectively.

25] Genetics and transformation of mitochondria in the green alga Chlamydomonas

This chapter discusses genetics and transformation of mitochondria in the green alga Chlamydomonas. Molecular evidence strongly supports the endosymbiotic origin of mitochondria from alpha purple bacteria. Photosynthetic eukaryotes show the greatest diversity in mitochondrial genome size and structure, ranging from the 15-kb linear genome of the green alga Chlamydomonas reinhardtii to genomes of certain angiosperms that exceed one Mb. Although the mitochondrial genomes of numerous invertebrates and vertebrates and the liverwort Marchantia is completely sequenced, and the genes they encode are well characterized, the genetic systems in these organelles are poorly developed. Mitochondria of animal cells lacking DNA can be obtained by prolonged culture of cells in medium containing ethidium bromide, and pyruvate and uridine, which are essential for growth of the cell. Genetic dissection of mitochondrial structure and function in baker's yeast is possible because mitochondrial function is dispensable. Mitochondrial transformation in yeast is just beginning to be exploited to study expression of specific organelle genes, and much needs to be done to take advantage of this technique in Chlamydomonas.

Primary structure of barley genes encoding quinone and chlorophyll a binding proteins of photosystem II.

The psbA, psbD and psbC genes encoding the quinone binding D-1 and D-2 apoproteins and the 44 kD chlorophyll a-apoprotein 3 have been located in the chloroplast genome of barley. They are found on a 23 kbp SalI restriction endonuclease fragment in the large single copy region of the chloroplast DNA adjacent to the inverted repeat. As in other species the psbD and psbC genes have reading frames which overlap by 53 bp. They are transcribed in the same direction but translated with a frameshift of one nucleotide. Ten amino acid substitutions are found among the 18 N-terminal residues of the D-2 polypeptide if barley, spinach, tobacco, pea and the liverwort Marchantia are compared. Only 8 substitutions are present among the 335 other residues of the D-2 polypeptide. The amino acid residues located in the putative binding site for the special pair reaction center chlorophyll and the residues probably serving as ligands to non-heme iron in the D-1 and D-2 proteins of barley are strictly conserved when compared to those of purple bacteria and of other higher plants. Identity is also observed for the residues of importance in the binding of quinones.

PHYLETIC PHENOCOPIES: A USEFUL TECHNIQUE FOR PROBING THE GENETIC AND DEVELOPMENTAL BASIS OF EVOLUTIONARY CHANGE.

EvolutionVolume 40, Issue 2 p. 422-425 Note and CommentFree Access PHYLETIC PHENOCOPIES: A USEFUL TECHNIQUE FOR PROBING THE GENETIC AND DEVELOPMENTAL BASIS OF EVOLUTIONARY CHANGE G. L. Stebbins, G. L. Stebbins Department of Genetics, University of California, Davis, CA, 95616Search for more papers by this authorDominick V. Basile, Dominick V. Basile Department of Biological, Sciences H. H. Lehman College, CUNY, Bronx, NY, 10468Search for more papers by this author G. L. Stebbins, G. L. Stebbins Department of Genetics, University of California, Davis, CA, 95616Search for more papers by this authorDominick V. Basile, Dominick V. Basile Department of Biological, Sciences H. H. Lehman College, CUNY, Bronx, NY, 10468Search for more papers by this author First published: March 1986 https://doi.org/10.1111/j.1558-5646.1986.tb00483.xCitations: 12AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume40, Issue2March 1986Pages 422-425 ReferencesRelatedInformation

Some Factors Evoking Formation of Sex Organs in Funaria

In Funaria hygromrnetrica, low temperature (100 C) is the critical factor in the induction of sex organs while day length seems to have no effect as long as a certain minimum period of illumination is provided. The purpose of this study was to investigate some of the factors which effect the initiation of sexuality in Funaria hygrometrica Hedw. as evidenced by the formation and functioning of antherida and archegonia. Although the stimuli which trigger the onset of the reproductive phase have been investigated in algae, fungi, and flowering plants, the Bryophyta have been relatively neglected in this respect. Photoperiod has been implicated in gametangiophore production in the liverwort Marchantia (Voth & Hamner 1949) and has been shown to affect development, although not to cause initiation, of the sporophyte of Polytrichum aloides (Hughes 1962). Morris (1958) stated that in five species of leafy liverworts, the onset of sexual reproduction is primarily a photoperiodic response. Benson-Evans (1964) reported that sexuality in Sphagnum plumulosum is initiated by short days but that Polytrichum aloides appears to be day length neutral and, in fact, initiation of sexuality is temperature-dependent. Von Wettstein (1924) was able to bring about sexual reproduction in Funaria hygrometrica by 'culturing it in pots on the north side of his Moosgewichshaus where, he stated, the plants would remain especially cool in