The cannabis industry is approaching a crossroads. While cultivators must ensure they are getting the greatest yield per square foot, an increasingly competitive landscape and sophisticated consumer means growers must also balance the need for volume with quality, consistent and award-winning cannabis strains.
Tissue culture propagation represents a significant leap forward in cannabis cultivation, ultimately benefiting both the grower and the consumer. The proprietary technology behind our sterilization and storage process results in the isolation of premium cannabis genetics in a clean, contaminant-free environment. Since our inception, we’ve been focused on setting a higher standard in medical (and one day adult use) cannabis by growing craft cannabis on a commercial scale through utilization of this cutting-edge cultivation technique. When taken in total, Maitri boasts access to a library of 243 unique cannabis strains, one of the largest collections in the U.S.
Trouble with Traditional Cultivation
Pathogens, insects and cross contamination all threaten the viability and value of cannabis plants. In many ways, current cannabis cultivation techniques compound these issues by promoting grams per square foot above all else and packing plants into warehouse sized grows where issues can quickly spread.
In these close quarters, pests can swiftly move from plant to plant, and even from generation to generation when propagating from clones or growing in close quarters. Similarly, pathogens can leap between susceptible plants, damaging or killing plants and cutting into a cultivator’s bottom line.
Of particular concern is hop latent viroid. Originally identified in hops, a genetic relative of cannabis, this infectious RNA virus has torn through the cannabis industry, endangering genetics, causing sickly plants and reducing yields. Plants cloned using traditional methods from an infected mother are vulnerable to the disease, making hop latent viroid a generational issue.
Minimizing or even eliminating these threats helps to protect the genetic integrity of cannabis strains and ensures they can be enjoyed for years to come. That is where the sterilization stage in tissue culture cultivation stands out.
Like cloning, tissue culture propagation offers faster time to maturity than growing from seed, allowing for a quicker turnaround to maximize utility of space, without overcrowding grow rooms. However, it also boasts a clean, disease-free environment that allows plants to thrive.
Tissue Culture Cultivation
Tissue culture cultivation allows for viable plant tissue to be isolated in a controlled, sterilized environment. Flowering plants can then be grown from these stored genetics, allowing for standardization of quality strains that are free of contamination and disease from the very beginning. Tissue culture cultivation also takes up less room than traditional cloning, freeing up valuable square footage.
This propagation process begins with plants grown to just before flowering and harvested for their branch tips. These branch tips undergo a sterilization process to remove any environmental contamination. This living plant material (known as explants) gets fully screened and tested for potential contaminants.
If it passes, the sample is stabilized and becomes part of the Maitri genetic library for future cultivation. If any contamination is discovered, the plant is selected for meristem isolation, an intensive isolation technique at the near cellular level.
Once sterilized and verified to be clean, the samples — often just an inch tall — are isolated into individual test tubes in our proprietary nutrient-rich medium for storage indefinitely. The cuttings are held in these ideal conditions until tapped for cultivation. This process allows Maitri to maintain an extensive library of clean, disease-free cannabis genetics ready to be grown.
Benefits for Medical Cannabis Patients
One of the chief benefits of tissue culture propagation is that it creates exact genetic replicas of the source plant. This allows growers like Maitri to standardize cannabis plants, and thus the cannabis experience. That means patients can expect the same characteristics from Maitri grown strains every time, including effects, potency and even taste and smell. Keeping reliable, top quality strains in steady rotation ensures patients have access to the medicine they need.
Preserving Plant Genetics
Beyond the benefits that tissue culture cultivation provides for the patient, this approach to testing, storing and growing cannabis plants also goes a long way towards protecting cannabis genetics into the future.
Cannabis strains are constantly under assault from pests and disease, potentially destroying the genetics that make these strains so special. Over-breeding and a dwindling demand for heirloom strains also threatens the loss of some individual plant genetics. Having a collection of genetics readily available means we can quickly cultivate strains to best meet consumer demand. Additionally, maintaining a rich seed bank that features both legacy and boutique strains allows us to have options for future tissue culture cultivation or for future new strain development.
Advancing Cannabis Research
Due to federal prohibition, researching cannabis, especially at the university level, can be extremely difficult. Additionally, the cannabis material that researchers have access to is largely considered to be subpar and wildly inconsistent, placing another barrier to researching the physiological effects of the plant. Clean, safe and uniform cannabis is a necessity to generate reliable research data. Utilizing tissue culture cultivation is a smart way to ensure researchers have access to the resources they need to drive our understanding of the cannabis plant.
Plant genetics are an important consideration for cultivators planning to grow cannabis crops. Genetics can affect how well a plant grows in a particular environment under various conditions and have a major impact on the production of cannabinoids, terpenes as well as other molecules and traits expressed by the plant.
Front Range Biosciences is a hemp and cannabis genetics platform company, leveraging proprietary next generation breeding and Clean Stock® tissue culture nursery technologies to develop new varieties for a broad range of product applications in the hemp and cannabis industries. FRB has global reach through facilities in Colorado, California and Wisconsin, and a partnership with the Center for Research in Agricultural Genomics in Barcelona, Spain. FRB is headquartered in Lafayette, Colorado.
We spoke with Jonathan Vaught, Ph.D., CEO and co-founder of Front Range Biosciences. Jonathan co-founded Front Range in 2015 after a successful career in the diagnostics and food testing industries.
Jonathan Vaught: This was a collaborative project between the BioServe group at the University of Colorado Boulder, which is a part of their aerospace engineering program. They do research on the International Space Station, and they have for quite some time. We partnered with them and another company, Space Technology Holdings, a group that’s working on applications of space travel and space research. We teamed up to send tissue culture samples to the space station and let them sit in zero gravity at the space station for about a month, and then go through the reentry process and come back to Earth. We brought them back in the lab to perform some genomic analyses and try to understand if there’s any underlying genetic changes in terms of the plants being in that environment. We wanted to know if there was anything interesting that we could learn by putting these plant stem cells and tissue cultures in an extreme environment to look for stress response, and some other possible changes that might occur to the plants by going through those conditions.
Aaron: That’s an interesting project! Are there any trends that you’re following in the industry?
Jon: We’re excited to see ongoing legalization efforts around the world. We’ve seen continued progress here in the United States. We still have a long way to go, but we’re excited to see the additional markets coming onboard and regulations moving in the right direction. Also, we’re excited to see some of the restorative justice programs that have come out.
Aaron: How did you get involved at Front Range Biosciences?
Jon: It really starts with my background and what I was doing before Front Range Biosciences. I’ve spent more than 15 years developing commercializing technologies in human diagnostics, food safety and now agriculture.
I started my career during graduate school in biotech at the University of Colorado at Boulder, where I helped develop some of the core technology for a human diagnostic startup company called Somalogic here in Colorado. I went to work for them after finishing my dissertation work and spent about six years there helping them grow that company. We ended up building the world’s largest protein biomarker discovery platform primarily serving pharmaceutical companies, hospitals and doctors, with personalized medicine and lab tests for things like early detection of chronic illness, cancer, heart disease and inflammation.
I then went to another startup company called Beacon Biotech, that was interested in food safety. There I helped develop some similar technologies for detecting food-borne illness — things like salmonella, listeria and E. coli. That was my introduction to big food and big agriculture. From there, I went to help start another company called Velocity Science that was also in the human diagnostic space.
Along the way, I started a 501(c)3 nonprofit called Mountain Flower Goat Dairy, a dairy and educational non-profit that had a community milk-share, which included summer camps and workshops for people to learn about local and sustainable agriculture. I became more and more interested in agriculture and decided to take my career in that path and that’s really what set me up to start Front Range Biosciences.
Aaron: Do you have any co-founders?
Jon: I have two other co-founders. They both played various roles over the last four years. One was another scientist, Chris Zalewski, PhD. He currently works in the R&D department and helps oversee several different parts of the company including pathology and product development. My other co-founder, Nick Hofmeister served as chief strategic officer for the last few years, and has helped raise the majority of our funding. We’ve raised over $45 million dollars, and he played a big role in that.
Aaron: What makes you different from other cannabis seed companies?
John: We’ve built the first true cannabis genetics platform. What I mean by that is we built a platform that allows us to develop and produce new plant varieties that support both the hemp and the cannabis markets. To us, it’s all cannabis. Hemp and cannabis are scientifically the same plant. They just have different regulatory environments, different products and different markets, but we stay focused on the plant. Our platform is built on several different pillars. Genetics are one of the core pieces, and by genetics I mean, everything from molecular based breeding to marker assisted breeding to large germplasm collections. We collect different varieties of germplasm, or seed, from all over the world and use those to mix and match and breed for specific traits. We also have large nursery programs. Another one of our pillars of the platform includes greenhouse nursery production — everything from flowering cannabis plants to producing cannabis seeds to cloning and producing mother plants and rooted cuttings or clones.
Then tissue culture is another part of the platform, it’s basically the laboratory version of a greenhouse nursery. It’s housed in a sterile environment and allows us to produce plants that are clean and healthy. It’s a much more effective, modern way to manage the nursery. It’s part of our clean stock program, where we start clean, stay clean, and you can finish clean. It’s really built on all of those different pieces.
We also have capabilities in analytical chemistry and pathology, that allow us to better understand what drives performance and the plants, and both different regions as well as different cannabinoid products or terpene products. All of the science and capabilities of the platform are what allow us to create new varieties faster, better, stronger.
Aaron: It sounds like you’re vertically integrated on the front-end of cannabis cultivation.
Jon: Absolutely, that’s a great way to think about it.
The last piece I’d say is that we have areas of research and development that cover the full span of multiple product lines. We think about it from an ingredient perspective. Cannabinoids and terpenes are certainly what drive a large part of the cannabis market in terms of edibles, smokable flower, vapes and extracts and the different effects and flavors that you get. We also are looking at other ingredients, like plant-based protein and hemp as a viable protein source and the ability for hemp to produce valuable fiber for textiles, as well as industrial building materials and applications.
Lastly, there are additional small molecules that we’re working on as well from a food ingredients perspective. There are all kinds of interesting compounds. Everybody talks about the cannabinoids and terpenes, but there are also things like flavonoids, and some other very interesting chemistries that we’re working on as well.
Aaron: What geographies are you currently in?
Jon: Colorado and California primarily and we have a small R&D partnership in Barcelona.
Aaron: Do you have plans for expansion beyond that?
Jon: Our current headquarters are out of Colorado, and most of our Colorado operations right now are all hemp. Our hemp business is national and international.
We work with a licensed cannabis nursery partner in California which is our primary focus for that market, but we will be expanding the cannabis genetics and nursery program into Colorado next year. From a regulated cannabis perspective, that’s the first move. Beyond that, we’re in conversations with some of the multi-state operators and cannabis brands that are emerging to talk about how to leverage our technology and our genetics platform across some of the other markets.
Aaron: How do you think about genetics in your products?
Jon: Genetics means a lot of things to different folks depending on your vantage point and where you sit in the supply chain. Our business model is based on selling plants and seeds. At the end of the day, we don’t develop oils, extracts and products specifically, but we develop the genetics behind those products.
For us, it’s not only about developing genetics that have the unique qualities or ingredients that a product company might want like CBD, or other minor cannabinoids like THCV for example, but also about making sure that those plants can be produced efficiently and effectively. The first step is to introduce the ingredient to the product. Then the second step is to make sure that growers can grow and produce the plant. That way they can stabilize their supply chain for their product line. Whether it’s for a smokable flower product, or a vape product, or an edible product, it’s really important to make sure that they can reproduce it. That’s really how we think about genetics.
Aaron: What is a smart plant? That’s something I saw on your website.
Jon: It’s really about plants that perform under specific growing regions, or growing conditions. For example, in hemp, it’s one thing to produce CBD or CBG. It’s another thing to be able to produce it efficiently in five different microclimates around the U.S. Growing hemp in Florida or Alabama down on the Gulf Coast versus growing on the Pacific Northwest coast of Washington, or Oregon are two very different growing conditions that require smart plants. Meaning they can grow and thrive in each of those conditions and still produce the intended product. Generally, the different regions don’t overlap. The genetics that you would grow in Pacific Northwest are not going to do as well as some better selected varieties for the South East.
It’s not only different outdoor growing regions, but it’s different production styles too. When you think about regulated cannabis the difference between outdoor and indoor greenhouse is mixed light production. Even with hydroponic type growing methods, there are lots of different ways to grow and produce this plant and it’s not a one size fits all. It’s really about plants that perform well, whether it’s different regions in the United States in outdoor production or different indoor greenhouses with mixed lights and production methods.
Aaron: You market CBG hemp as a product line. What made you start with CBG? Is that a pull from the market or something you guys see trending?
Jon: So I think it’s a little bit of both. We offer CBD dominant varieties and CBG dominant varieties of hemp. We also now have other cannabinoids in the pipeline that we’ll be putting out in different varieties next year. Things like CBC as well as varins, or propyl cannabinoids. Also things like CBDV, CBCV, or CBGV, which are the propylcannabinoid versions of the more familiar compounds.
There was a lot of market demand for CBG. It was a fairly easy cannabinoid to produce as a single dominant cannabinoid similar to CBD or THC. There’s a lot of up-and-coming demand for some of the other minor cannabinoids. Up until a few years ago, CBD was considered a minor cannabinoid. It wasn’t until Charlotte’s Web in the Sanjay Gupta story that it became a major cannabinoid. So I think we see some level of market pull across the category.
On the flip side of that, we have one of the world’s largest R&D teams and consolidated expertise in terms of cannabis. We see the potential for minor cannabinoids, and even terpenes and other compounds like flavonoids to have wide ranging implications in human health. Everything from wellness products, to active pharmaceutical ingredients, to recreational products. From our perspective, that’s the reason why we’re pushing these ingredients. We believe that there are a lot of good products that come out of this work and the genetics that produce these minor cannabinoids.
Aaron: Okay, great. And then last question, is there anything you’re interested in learning more about?
Jon: I think the most exciting thing for me, given my background in clinical diagnostics and human health, is to see more data around how all of these different compounds of the plant can support improved wellness, health and nutrition. I think we’ve only scratched the tip of the iceberg. This type of research and data collection takes years, even decades, especially to see outcomes over time of people using these products. I’m really excited to see more of that and also hopefully be able to make stronger conclusions about some of the benefits that can be had from this plant.
Aaron: That’s the end of the interview, thanks Jon!
The journal Frontiers in Plant Science recently shared an important article from researchers at Simon Fraser University in British Columbia, highlighting the “Pathogens and Molds Affecting Production and Quality of Cannabis Sativa.”
As a chemist focused on the science of preventing and mitigating mold in greenhouse and indoor cannabis grow facilities, this piece was fascinating to me. Like many others, it details and explains prevalent mold like Penicillium, Cladosporium and Aspergillus – things I see in grows every day.
But wait, there’s more fungi
The research and resulting article also brought up another type of fungi – endophytic mold. Endophytic mold usually lives symbiotically with plants, or is at least beneficial for both plant and fungi.
But not always.
In the past, the industry has believed that damaging mold spores were found on the outside of the flower. When moved, that flower would release the spores and send them flying – often creating massive cross-contamination issues for indoor grows.
“While cannabis is an incredibly powerful plant in terms of its medicinal properties, it is unfortunately highly susceptible to many pest and pathogens,” says Hope Jones, PhD, CEO, Adivina & ECS. “And it is this susceptibility that is so challenging to many inexperienced or undisciplined grow operations.”
Now, however, we know that there’s another culprit to add to the list: the inner parts of the plant can also be a source of endophytic cross contamination and mold.
Since it grows inside of the plant, this fungus creates high spore counts that can cross contaminate from outside, into the flower.
Treating mold in a facility
Here’s the good news:
This seemingly bad news – that there’s a new fungus to worry about, and it is inside the flower – may actually help cannabis grows struggling with mold, and those who are following the proper protocols already.
Effective mitigation protocols can include things like treating HVAC systems, controlling humidity, using products like chlorine dioxide to treat irrigation lines, enforcing protective clothing and shoe covers for employees, reducing the amount of in-and-out for employees around grow rooms.
These are important upstream and environmentally-focused integrated pest management (IPM) programs that will usually keep facilities clean and relatively mold-free.
But if these programs are in place, and there’s still an issue, Endophytic fungi may be to blame.
If you are having ongoing mold issues but have ruled out cross-contamination and a facility without proper protocol, look to the mother plant.
“Small mistakes in agricultural practices are amplified with cannabis,” Dr. Jones continues. “And today’s propagation practices of traditional cloning add to this vulnerability. Cannabis is an annual plant and by keeping mothers in a perpetual state of vegetative growth for years, and taking repetitive cuttings produces clones in a highly stressed state. This stressed state diminishes genetic potential and weakens a plant’s ability to fight disease and pests.”
Testing for and addressing endophytic fungi
If these concerns are ringing a bell, remember, there is also a way to test for Endophytic mold.
Checking cuttings from suspected mother plants over a period of time is the best way to see if the Endophytic mold is present.
A section of the mother plant cutting is placed into a solution (for example, as outlined by the article, a very concentrated hypochlorite followed by 70% Ethanol) that will kill all of the microorganisms that are present on the surface of the plant tissues.
From there, an unadulterated dissection of the internal tissues can be extracted and cultured for quantification and identification of endophytic fungi.
“Tissue culture offers a form of genetic rebooting returning the plant to its natural genetic potential and thereby strengthening its natural ability to defend against environment assault,” says Dr. Jones. “It also allows the breeder to conduct pathogenic disease testing which provides the entire industry with a higher level of scientific certainty and analysis.”
If you find this mold inside of the mother plant, your facility’s mold problem could be a systemic issue, not an environmental one.
If you do find that Endophytic mold is causing issues, of course, you may have to destroy the mother plant.
This should not mean the end of a strain. Tissue culture on a cutting is an option that can eliminate the unwanted fungi and save the genetics. Using those genetics to regrow a mother will start fresh and avoid the intrinsic mold that was plaguing the strain prior.
The practice of checking mother plants for Endophytic mold is not yet commonplace in cannabis, but the hemp business is leading the way.
They’re testing to create very clean plants, so you don’t have issues during cultivation.
Major growers in the U.S. could save millions in lost harvests with mold mitigation. If your current IPM program isn’t doing the trick, you may want to follow in hemp’s footsteps and look inside the plant.
In the first part of this series, we introduced Dr. Hope Jones, who took her experience in tissue culture from NASA and brought it to the cannabis industry and C4 Laboratories. We discussed some of the essential concepts behind tissue culture and defined a few basic terms like micropropagation, totipotency, explants and cloning. Now let’s get into some of the issues with cloning from mother plants and the advantages that come with using tissue culture for propagating and cultivating cannabis.
Time & Resources
Taking cuttings from mother plants is arguably the most popular method of propagating cannabis plants. It is a process that requires significant real estate, resources and labor. “Moms can take up a great deal of space that is not contributing directly to production,” says Dr. Jones. “I know from experience that scaling up production and/or adding new strains to the production line requires significant time and resources to raise and maintain new healthy and productive mother plants.” Each mother plant produces a limited number of clones per harvest period and over the course of her life cycle.
By using tissue culture, a cultivator can generate an almost infinite number of clones from one plant cutting. With so many growers calculating their costs-per-square-foot, micropropagation is an effective tool to save space, labor and time, thus increasing profit margins. “Just to put it in perspective: Holly Scoggins’ book Plants From Test Tubes, cites a Day Lily cultivator who uses micropropagation to produce 1,000 plants in 30 square feet of shelf space each week,” says Dr. Jones. “Using conventional methods, one would need a half-acre to produce the same amount of plants.” Cultivators can produce a much greater number of plants-per-square-foot by using micropropagation effectively.
Early Health & Vigor
Most tissue culture methods use sterilized vessels that contain sugar-rich media to support growth of plantlets before they can photosynthesize on their own. “The media is prepped, poured into vessels, and placed in an autoclave (or pressure cooker) where it is subjected to high temps and pressure to achieve proper sterility.”
The sterile environment and rich growth media supplies plantlets with an abundance of everything they need. “When plantlets emerge from culture, they are pathogen-free, with a stockpile of food and nutrient reserves that support rapid growth and vigor, superior to conventional cuttings,” says Dr. Jones.
Stress & Disease
As any grower knows, mother plants can sometimes experience stress and disease. This might come in the form under or over-watering, heat stress, spider mites, whiteflies, mold and viruses. “Any stress or infection that a mother plant is subjected too can impact progeny health and productivity in a couple of ways,” says Dr. Jones.
For example, diseases like powdery mildew and tobacco mosaic virus are often systemic, meaning that pathogens have spread to almost every tissue in the plant. Once infected, it is impossible to completely eliminate pathogens from tissues. Therefore any cuttings made from a diseased mother plant, even if they look perfectly healthy, will also be infected and can eventually present disease symptoms like reduced productivity and/or plant death, according to Dr. Jones.
How does tissue culture get around this problem? Remember that explants (small tissue samples used as starting material) can be extracted from any part of the plant. Meristematic cells in shoot tips and leaves are the source of new plant growth. Dr. Jones explains that these cells, and the first set of primordial leaves are not connected directly to the vascular tissue, the plant’s transport system by which pathogens spread. Therefore, meristematic cells tend to be disease-free, whatever the condition of the mother. It takes a sharp blade, a dissecting microscope, and a lot of experience to learn, but as Dr. Jones explains, “harvesting explants from meristems is a routine micropropagation technique used by ‘Big Horticulture.’ One example is the strawberry. Viruses and pathogens are so prevalent that the strawberry industry must use meristematic culture to ensure pathogen free progeny.”
Now let’s talk about epigenetics. We know that plants don’t have the option of physically moving away from stress or predation. Instead, they have evolved sophisticated ways of changing their own biology to adapt to and/or protect themselves. “Consider what happens to a mom exposed to a pathogen. The infected plant will start expressing (turning on) genes and making proteins that contribute to pathogen resistance,” says Dr. Jones. “These changes to gene expression are partly regulated by epigenetic modifications, chemical changes to DNA that increase or decrease the likelihood a cell will express a particular gene, but that do not actually modify the gene itself. Like annotations to a piece of music, epigenetic modifications don’t change the notes but rather how loud or soft, quickly or slowly the notes are played.”
This is where it gets interesting. “Epigenetic modifications can be systemic and long lived. Plants infected by a pathogen or stressed by drought will present widespread epigenetic modifications to their DNA,” says Dr. Jones. “For an annual plant like cannabis, those modifications are relatively permanent. Thus a cutting from a mom having drought or pathogen adapted epigenetic programming will inherit that modified DNA and behave as if it were experiencing that stress, whether present or not.”
In the wild, this adaptability is critical for plant survival and reproduction, but to a grower, this is a less-than-ideal scenario. “The epigenetic modifications allowed the mother to tolerate the stress, which is great from the perspective of survival and fitness, but it comes at a cost. Some of the finite energy and resources that usually support plant growth and reproduction are instead channeled to stress response,” says Dr. Jones. This trade off results in reduction in overall plant yield and quality. “Those epigenetic changes result in a new phenotype for that mother,” says Dr. Jones. “All cuttings from her will reflect the new phenotype. This is one major mechanism underlying what many in the cannabis industry (incorrectly) call ‘genetic drift,’ or the loss of vigor over successive clonal generations.”
This is again where tissue culture can be such a game changer. The process of dedifferentiation, as explained in part 1 of this series, can rejuvenate a “tired” mother plant by inducing a kind of reboot– clearing accumulated epigenetic modifications that negatively impact progeny vigor and productivity. In the third part of this series, we will discuss the five stages of micropropagation, detailing the process of how you can grow plantlets in tissue culture. Stay tuned for more!
Dr. Hope Jones, chief scientific officer of C4 Laboratories, believes there are a number of opportunities for cannabis growers to scale their cultivation up with micropropagation. In her presentation at the CannaGrow conference recently, Dr. Jones discussed the applications and advantages of tissue culture techniques in cannabis growing.
Dr. Jones’ work in large-scale plant production led her to the University of Arizona Controlled Environment Agriculture Center (CEAC) where she worked to propagate a particularly difficult plant to grow- a native orchid species- using tissue culture techniques. With that experience in tissue culture, hydroponics and controlled environments, she took a position at the Kennedy Space Center working for NASA where she developed technologies and protocols to grow crops for space missions. “I started with strawberry TC [tissue culture], because of the shelf life & weight compared with potted plants, plus you can’t really ‘water’ plants in space- at least not in the traditional way,” says Dr. Jones. “Strawberries pack a lot of antioxidants. Foods high in antioxidants, I argued, could boost internal protection of astronauts from high levels of cosmic radiation that they are exposed to in space.” That research led to a focus on cancer biology and a Ph.D. in molecular & cellular biology and plant sciences, culminating in her introduction to the cannabis industry and now with C4 Labs in Arizona.
Working with tissue culture since 2003, Dr. Jones is familiar with this technology that is fairly new to cannabis, but has been around for decades now and is widely used in the horticulture industry today. For example, Phytelligence is an agricultural biotechnology company using genetic analysis and tissue culture to help food crop growers increase speed to harvest, screen for diseases, store genetic material and secure intellectual property. “Big horticulture does this very well,” says Dr. Jones. “There are many companies generating millions of clones per year.” The Department of Plant Sciences Pomology Program at the Davis campus of the University of California uses tissue culture with the Foundation Plant Services (FPS) to eliminate viruses and pathogens, while breeding unique cultivars of strawberries.
First, let’s define some terms. Tissue culture is a propagation tool where the cultivator would grow tissue or cells outside of the plant itself, commonly referred to as micropropagation. “Micropropagation produces new plants via the cloning of plant tissue samples on a very small scale, and I mean very small,” says Dr. Jones. “While the tissue used in micropropagation is small, the scale of production can be huge.” Micropropagation allows a cultivator to grow a clone from just a leaf, bud, root segment or even just a few cells collected from a mother plant, according to Dr. Jones.
The science behind growing plants from just a few cells relies on a characteristic of plant cells called totipotency. “Totipotency refers to a cell’s ability to divide and differentiate, eventually regenerating a whole new organism,” says Dr. Jones. “Plant cells are unique in that fully differentiated, specialized cells can be induced to dedifferentiate, reverting back to a ‘stem cell’-like state, capable of developing into any cell type.”
Cannabis growers already utilize the properties of totipotency in cloning, according to Dr. Jones. “When cloning from a mother plant, stem cuttings are taken from the mother, dipped into rooting hormone and two to five days later healthy roots show up,” says Dr. Jones. “That stem tissue dedifferentiates and specializes into new root cells. In this case, we humans helped the process of totipotency and dedifferentiation along using a rooting hormone to ‘steer’ the type of growth needed.” Dr. Jones is helping cannabis growers use tissue culture as a new way to generate clones, instead of or in addition to using mother plants.
With cannabis micropropagation, the same principles still apply, just on a much smaller scale and with greater precision. “In this case, very small tissue samples (called explants) are sterilized and placed into specialized media vessels containing food, nutrients, and hormones,” says Dr. Jones. “Just like with cuttings, the hormones in the TC media induce specific types of growth over time, helping to steer explant growth to form all the organs necessary to regenerate a whole new plant.”
Having existed for decades, but still so new to cannabis, tissue culture is an effective propagation tool for advanced breeders or growers looking to scale up. In the next part of this series, we will discuss some of issues with mother plants and advantages of tissue culture to consider. In Part 2 we will delve into topics like sterility, genetic reboot, viral infection and pathogen protection.
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