Team:Cambridge-JIC/Marchantia

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<h2>Marchatia</h2>
 
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<p>Ginny suggested that we should have a page exposing Marchantia and extolling its virtues as a new chassis</p>
 
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yes she did!
 
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<h1> Welcome to Mar-Cam-tiamania Land!! </h1>
 
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Let us introduce to you to Marchantia Polymorpha (or Polly for short). <br>
 
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On this page you can find general information about our little plant, the reasons we love her and her path to being the new chassis for plant Synthetic Biology (and some trivia at the end).
 
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<ul>
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<h1>Introduction to <i>Marchantia polymorpha</i></h1>
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<h2> Who is Marchantia? </h2>
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Let's leave the botanical jargon and head to the gardens.<br>
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<p><i>Marchantia polymorpha</i> is a member of one of the most primitive divisions of land plants, the liverworts. It grows as flat sheets of tissue called thalli (a singular one is called a thallus), and once spotted is a common sight by the sides of ponds and streams, and in shaded gaps in masonry throughout the world. Each plant grows to be between two and ten centimetres across, and is quite unlike more familiar plants in a number of ways.</p>
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<h3> Intro to Byrophytes and how to get in the clang</h3>
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<p align="center"><img src="https://static.igem.org/mediawiki/2014/f/f8/Thalli%2C_phores_and_a_shoe.jpg" width = 800> </img> </p>
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<ul>
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<p align="center">Some <i>Marchantia plants</i> near a shoe for scale
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Primitive plants are everywhere and together are called Byrophytes. <br>
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<br>
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<ul>
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<p>Liverworts are defined by their simplicity. <i>Marchantia</i>, like other liverworts, has no vascular tissue and anchors itself not with true roots but with very long single cells called rhizoids, which become a matted array of filaments extending only ten or fifteen millimetres into the substrate. This simplicity is due to the retention of primitive characteristics evolved in early plants. One of these is the absence of flowers or seeds and the propagation of the plant in two old-fashioned ways.</p>
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Byrophytes are divided into three lineages.<br>
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In evolutionary order these are:
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<li>Marchantiaphyta or Liverworts (that's Poly!)</li>
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then came <li>Mosses (byrophyta)</li>
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and finally the newer <li>Hornworts or Anthocerotophyta.</li>
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then came all the rest.
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</ul>
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<h4>Nature's strange ways: Role-Reversal Byrophytes and what makes them special </h4>
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<p>One of these ways is through the splash cups (or gemma cups) which pockmark the upper surface of the plant. Inside these cups grow tiny sproutlings of <i>Marchantia</i> called gemmae, with undeveloped rhizoids and thalli. They are halted from growing large inside their cups by the presence of a compound called lunularic acid in the space they inhabit, placed there by the tissue of the splash cup. When it rains, drops which fall into these cups rebound out and take these tiny gemmae with them, carrying them to the soil. Once on solid ground, they start to grow into a new individual.</p>
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<ul>
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Byrophytes are united by unique features.<br>
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These include:<br>
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<li>Sexual Propagation by Spores</li>
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<li>No cumbersome flowers or energy absorbing seeds</li>
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<li>No lignin (what makes plants tough) or vascualture</li>
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and last but not least
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<li>a reversed life cycle!</li>
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Byrophytes are indeed often referred to as 'Up-Side-Down' or 'Role-Reversal' plants.<br>
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Their life cycle is the opposite of most:<br>
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We and other organisms spend our life as diploids. (two sets of chromosomes, one from Dad, one from Mother).<br>
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We specialize a set of cells in our reproductive organs which undergo meiosis, forming a haploid egg or sperm.<br>
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When the sperm and the egg come together, they form a haploid organism which grows. And the cycle starts again<br>
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Byrophytes live most of their life as haploids (only have one copy of their genes!). A set of cells differentiate to become the ova and the sperm. When the haploid sperm reaches the haploid ova, they fuse, become diploid for a short time, and then undergo meiosis (split genome) to form two haploid plants!<br>
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<p align="center"><img src="https://static.igem.org/mediawiki/2014/1/1f/Gemma_Cup.jpg" width = 800> </img> </p>
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Intrigued by this oddity? Go to 'Marchantia's Life Cycle' to find out more.<br>
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<p align="center">A gemma cup with gemmae visible inside
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</ul>
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But let's not underestimate them...<br>
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<h3>Close up on Mar-cam-tiophytes (liverworts) </h3>
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<br>
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<ul>
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Primitve does not mean frail; quite the contrary.<br>  
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<p><i>Marchantia</i>can reproduce sexually as well as through this ‘fragmentation’, and is in fact dioecious, meaning that an individual plant is either a male or a female. When induced by a shift in ambient light to far red, which signals that other plants are looming overhead, strange mushroom-like structures begin to sprout from the top of each plant. In males, these eventually take the form of a flat polygonal table, in females, the sprouts become archegonia, which look like miniature palm trees and when mature will bear eggs. </p>
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<h4> Looks, Location and Loveliness </h4>
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<p>The antheridia, as the male table-like structures are called, produce two-tailed sperm instead of the pollen you might expect. These are spread by rain to the waiting eggs of the archegonia , which they fertilise and induce to become hardy spores. These spores number in the thousands in each archegonium, which when twinned with the dispersal of gemma makes <i>Marchantia polymorpha</i> very prolific.</p>
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Poly can be found found worldwide from tropical and arctic climates to your backyard! She likes moist soil or rocks in damp habitats. Her favourite hide-outs include banks of pools and rivers, bogs, fens and dune slacks.<br>
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You can easily find her in man-made habitats such as gardens, paths and greenhouses. Some even dare calling her a horticultural weed!<br>
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After fires, she rapidly colonizes the burnt ground, restoring an eco-stystem___.
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<p align="center"><img src="https://static.igem.org/mediawiki/2014/c/c3/Arch_and_anth.jpg" width = 800> </img> </p>
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<h4>Morphology </h4>
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<p align="center">An archegonium, removed from a female plant (left) and an antheridium from a male plant (right)
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Liverworts are wither of the leafy or thalose variety.
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Marchantia Polymorpha is a thallose one.<br>
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Thallus means simply undifferentiated plant tissue. (not very descriptive)<br>
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The Dilemma: Food or Water?
 
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<ul>
 
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Being thin, flat with a large surface area is great to maximise sunlight absorption and to photosynthesise lots; this comes at a cost: water evaporation. Plants that thrive have evolved to an optimum intermediate.<br>
 
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Poly exhibits a beautiful simple morphological adaptation: air pores, the ancestors of the current stomata that most plants now have.<br>
 
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</ul>
 
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Rosette growth and Splash cups.<br>
 
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<ul>
 
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Poly grows out in a rosette shape. If a thallus reaches the soil, it can become the start of a new plant. However this doesn't get her very far.<br>
 
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At ___- weeks of development, a gemma cup appears at the centre of a thallus. The cup contains loose cells. As rain drops into the cup, the loose cells are propulsed out to find new ground to conquer.<br>
 
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This allows simple rapid asexual isogenic reproduction!.
 
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</ul>
 
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Reproductive Organs
 
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<ul>
 
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Sexual reproduction, which allows gene mixing between two plants is another matter.<br>
 
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Upon maturation at ___ weeks, the haploid Poly grows a reproductive stem at the centre.<br>
 
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For the males, this is called a __ and resembles a flat disc on a stem. It bears the spores that will disperse.<br>
 
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In females,an Umbrella appears.Underneath it is the protected Ova.<br>
 
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With wind, rain or a researchers hand, the sperm is let loose and flies to collect under the sticky surface of the umbrella.<br>
 
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Magic occurs: sperm and ova fuse. The diploid result undergoes recombination (gene mixing), divides multiple times and undergoes meiosis. The product is over ___ of haploid potential progeny with genomic diversity.<br>
 
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The reproductive organs can be stimulated to appear by exposure to infra-red light!
 
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</ul>
 
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</ul>
 
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<h1> The new Mar-vellous Chassis </h1>
 
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<ul>
 
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<h3>OpenPlant</h3>
 
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Synthetic Biology conferences used to be like vegetable gardens (or zoos), with every researcher working on different organisms: a longer courgette here, a sweeter tomato there. Great to make some tasty dishes but a real halt for science. The animal field concentrated their forces from dogs and cats to Drosophila fly and the C.elegant worm, and the green handed people went for Arabidopsis or Tabacco.<br>
 
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Focusing on these few and simple organisms allowed science, techniques to be shared and developed by a community and core concepts, true for any higher organisms, emanated from this thrust.<br>
 
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Arabidopsis, is a great plant however some of its disadvantages, long life cycle, height, complex development is refraining progress. A wave is now building up as we speak behind Marchantia to develop it as the new tool for Synthetic Biologists and Plant Scientists. _ Watch this space_ (or even better: read on!)
 
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<h4>The Beauty of Simplicity: Advantages of Marchy </h4>
 
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<ul>
 
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Why Marchantia as the new plant chassis? <br>
 
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For any system to be adopted and developed and made better it needs to be: simple, accessible and better than any previous system. Marchantia Polymorpha is just this.
 
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<ul>
 
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<li>Ancestor to all plants, she illustrates them all.<br>
 
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Her simple basic genome is more malleable</li>
 
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<li>Small in size makes for easy mass culture</li>
 
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<li>Rapid growth and germination reduces drastically the time of experiments (a big down fall of Arabodopsis)</li>
 
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<li>Easy transformability with Agorobacteria and possibility of electroporating the spores!</li>
 
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<li>Dioecious. Sexual reproduction allows for crossing of two strains of plants. Or if you want to keep an isogenic line, you can propagate her asexually.</li>
 
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<li>Easy long term storage of spores that requires no maintenance!</li>
 
<br>
<br>
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<li>Open Community Established</li>
 
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</ul>
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<p>The plants also have the ability to regenerate a whole new plant from a mere scrap of tissue, without the necessity of adding any hormones or other growth factors. Like in other primitive plants such as ferns, every cell contains a haploid genome except for a small amount of sexual tissue during the plant’s spore production stage.</p>
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</ul>
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<h4>Collaborators and future for iGEM</h4>
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The Welcome Trust has recently given a huge push to the Marchantia Lovers. And these are sprouting from everywhere<br>
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For future iGEM groups who'd like to join this Marchantia Community, here are some of the people who are already in the stream (and would love to here from you!)
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For advice, plant strains to get started or just some info, contact:
 
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<ul>
 
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<li>Us!</li>
 
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<li>The Haseloff group in Cambridge- (home of the OpenPlant)</li>
 
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<li>Tokyo</li>
 
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<li>MIT</li>
 
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<li>JIC</li>
 
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<li>UEA??</li>
 
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<li>Online Community!</li>
 
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</ul>
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<p>These characteristics and the simple structure of <i>Marchantia</i>’s genome, which often contains just one gene where in higher plants (like <i>Arabidopsis thaliana</i>) are found complex clusters of genes of similar and overlapping functions, make it a fascinating plant to study. They also make it a chassis perfect for synthetic biology. </p>
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<br></br>
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<h1> Marky Fun Facts & Trivia </h1>
 
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world records
 
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<h3>References</h3>
 
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<ul>
 
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<li
 
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Latest revision as of 01:39, 18 October 2014

Cambridge iGEM 2014

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Introduction to Marchantia polymorpha

Marchantia polymorpha is a member of one of the most primitive divisions of land plants, the liverworts. It grows as flat sheets of tissue called thalli (a singular one is called a thallus), and once spotted is a common sight by the sides of ponds and streams, and in shaded gaps in masonry throughout the world. Each plant grows to be between two and ten centimetres across, and is quite unlike more familiar plants in a number of ways.

Some Marchantia plants near a shoe for scale

Liverworts are defined by their simplicity. Marchantia, like other liverworts, has no vascular tissue and anchors itself not with true roots but with very long single cells called rhizoids, which become a matted array of filaments extending only ten or fifteen millimetres into the substrate. This simplicity is due to the retention of primitive characteristics evolved in early plants. One of these is the absence of flowers or seeds and the propagation of the plant in two old-fashioned ways.

One of these ways is through the splash cups (or gemma cups) which pockmark the upper surface of the plant. Inside these cups grow tiny sproutlings of Marchantia called gemmae, with undeveloped rhizoids and thalli. They are halted from growing large inside their cups by the presence of a compound called lunularic acid in the space they inhabit, placed there by the tissue of the splash cup. When it rains, drops which fall into these cups rebound out and take these tiny gemmae with them, carrying them to the soil. Once on solid ground, they start to grow into a new individual.

A gemma cup with gemmae visible inside

Marchantiacan reproduce sexually as well as through this ‘fragmentation’, and is in fact dioecious, meaning that an individual plant is either a male or a female. When induced by a shift in ambient light to far red, which signals that other plants are looming overhead, strange mushroom-like structures begin to sprout from the top of each plant. In males, these eventually take the form of a flat polygonal table, in females, the sprouts become archegonia, which look like miniature palm trees and when mature will bear eggs.

The antheridia, as the male table-like structures are called, produce two-tailed sperm instead of the pollen you might expect. These are spread by rain to the waiting eggs of the archegonia , which they fertilise and induce to become hardy spores. These spores number in the thousands in each archegonium, which when twinned with the dispersal of gemma makes Marchantia polymorpha very prolific.

An archegonium, removed from a female plant (left) and an antheridium from a male plant (right)

The plants also have the ability to regenerate a whole new plant from a mere scrap of tissue, without the necessity of adding any hormones or other growth factors. Like in other primitive plants such as ferns, every cell contains a haploid genome except for a small amount of sexual tissue during the plant’s spore production stage.

These characteristics and the simple structure of Marchantia’s genome, which often contains just one gene where in higher plants (like Arabidopsis thaliana) are found complex clusters of genes of similar and overlapping functions, make it a fascinating plant to study. They also make it a chassis perfect for synthetic biology.



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