![\"A](\"\/\/media.nature.com\/w800\/magazine-assets\/d41586-018-07081-x\/d41586-018-07081-x_16202276.jpg\")
<\/div>\n<\/div>A worker harvests cannabis near Nazareth, Israel. Although the drug is illegal, it has been permitted for medical use since the early 1990s.<\/span>Credit: Amir Cohen\/Reuters<\/p>\n<\/figcaption><\/figure>\n <\/p>\n <\/p>\n Canada has just become the second country in the world, after Uruguay, to legalize cannabis for all uses \u2014 a move that has prompted a flood of funding for basic research into cultivation of the plant, and a\u00a0clamour for scientists with expertise in genetics, bioengineering and growing practices<\/a>.<\/p>\n Elsewhere, research opportunities are generally more limited, and scientists studying the plant often have to go to extreme lengths to stay on the right side of local laws or to get sufficient funding for their work. Still, money is flowing in the places that have made medical cannabis a top priority. In the wake of Canada\u2019s law change,\u00a0Nature\u00a0<\/i>takes a tour of cannabis research outside the great white north.<\/p>\n No government has been as supportive of cannabis research as Israel\u2019s. It was here that Raphael Mechoulam, an organic chemist now at the Hebrew University of Jerusalem, first determined the chemical structures of the active component1<\/a><\/sup>, known as tetrahydrocannabinol (THC), as well as its non-psychoactive counterpart, cannabidiol2<\/a><\/sup>, in the 1960s. The country has since sought to establish itself as the world leader in studying cannabis for medicinal use.<\/p>\n Unlike some countries, including Canada, where government scientists still have limited access to high-THC varieties of the plant, Israel\u2019s agriculture ministry last year built a national centre for medical-cannabis research.<\/p>\n Housed at the Volcani Center in Rishon LeZiyyon, the government\u2019s cannabis farm includes thousands of plants spread across several greenhouses and indoor growing facilities. There, plant biologist Nirit Bernstein is trying to perfect cultivation and weed out bad practices. \u201cWe have to develop science-based protocols for optimizing the cultivation of this magical plant,\u201d Bernstein says. \u201cThere\u2019s very little scientific information that\u2019s available.\u201d<\/p>\n Public-sector spending on agricultural research is greater in the United States than just about anywhere else on Earth, other than China. Yet, when it comes to cannabis, the federal government doesn\u2019t spend anything on non-health\u2013related studies. That\u2019s because, even though high-THC varieties of the plant are now legal in some form in 30 US states (and Washington DC) and hemp is legal in another 19, cannabis is still considered an illicit drug at the national level \u2014 and all research conducted on it at any university that receives public funding must conform with federal regulations.<\/p>\n Studying cannabis DNA is allowed, and the government is gradually becoming more permissive of hemp cultivation. But any work on the basic biology of cannabis with higher levels of THC is strictly off-limits.<\/p>\n That has led to a few creative workarounds. In Colorado, where cannabis has been legal for recreational use since 2014, evolutionary genomicist Daniela Vergara at the University of Colorado Boulder created a foundation to support projects she couldn\u2019t do on campus. Unlike her university, the foundation can accept funding from the cannabis industry \u2014 money she then spends on sampling DNA from plants grown at local dispensaries and growers. Although she can analyse DNA-sequence data at the university, \u201cI don\u2019t touch the plant on campus or during my working hours\u201d, she says.<\/p>\n Uruguay\u2019s lawmakers were a step ahead of Canada\u2019s: in 2013, the nation became the first to fully legalize pot. Yet researchers have faced \u201cserious bottlenecks\u201d in gaining access to the plant, according to an analysis published in March3<\/a><\/sup>, and there\u2019s hardly any public money specifically set aside to foster cannabis research.<\/p>\n \u201cAlthough the law indicates that the state should promote scientific research on the subject, much remains to be done,\u201d says natural-products chemist Carlos Garc\u00eda, who leads the Interdisciplinary Group for Cannabis Research at the University of the Republic in Montevideo. \u201cFunds for that activity remain very scarce.\u201d<\/p>\n Plant molecular geneticist Astrid Agorio at the Clemente Estable Institute of Biological Research in Montevideo is attempting to profile the entire genetic structure of two varieties of Uruguayan cannabis with a budget of just US$6,000. She says she\u2019d like to start growing plants herself for this research, but can\u2019t afford the costs associated with building greenhouses and security systems. Because of that lack of funding support, \u201cUruguay can\u2019t be a world-leader in cannabis science now\u201d, Agorio says.<\/p>\n On the other side of the continent, one of South America\u2019s largest economies is looking to make a play in the global cannabis industry. Colombia\u2019s criminal cartels have been growing cannabis for decades, and the government hopes that farmers formerly working with traffickers will now put their skills to use for the legal market. This would entail destroying illegal crops and adopting new cultivation methods refined in the country\u2019s ornamental-flower industry, the second largest in the world.<\/p>\n \u201cWe\u2019re taking all the techniques that have been developed in the last 40 years in the cut-flower business in Colombia and adapting cannabis to it,\u201d says Marcelo de Siqueira, chief operating officer of PharmaCielo, a company headquartered in Toronto, Canada, that grows cannabis in Rionegro, Colombia. He contrasts that with what\u2019s being done elsewhere, where many companies are \u201ctaking an underground, inefficient, high-energy-consumption system that was typical of the black market and adapting it to large-scale production\u201d.<\/p>\n The country\u2019s cheap labour force and year-round 12-hour light cycles offer economic advantages, says Ryan Douglas, a cannabis consultant in Manizales, Colombia. \u201cIt\u2019s the ideal climate for growing cannabis,\u201d he says. And there\u2019s always room for improvement. At the Nueva Granada Military University in Bogot\u00e1, for example, natural-products chemist Ericson Coy-Barrera will soon start working with researchers at Khiron Life Sciences, another Toronto-based company with growing operations in Colombia, to validate and optimize protocols for drying the plant and extracting useful components.<\/p>\n Unlike in many other countries where cannabis is illegal, the plant is permitted on the premises of government-supported universities. That\u2019s a huge benefit, says Khiron\u2019s scientific research manager, Ana Mar\u00eda Borda in Ibagu\u00e9. The university is already equipped with state-of-the-art technology to support the work. \u201cEverything is in place,\u201d she says, \u201cand ready to go\u201d.<\/p>\n <\/p>\n <\/p>\n<\/div>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n (\uc6d0\ubb38: \uc5ec\uae30<\/u><\/a>\ub97c \ud074\ub9ad\ud558\uc138\uc694~)<\/p>\n <\/p>\n <\/p>\n Cannabis samples grow under specialized lights at Anandia Labs in Vancouver. Credit: James MacDonald for\u00a0Nature<\/i><\/p>\n<\/figcaption><\/figure>\n<\/div>\n Jonathan Page has been around cannabis all his life. Growing up on Canada\u2019s Vancouver Island in the 1970s, he was surrounded by hippie beachcombers and dope smokers. So after earning a PhD in plant biology and phytochemistry, he felt completely at ease working with the plant\u00a0Cannabis sativa\u00a0<\/i>as a postdoc in Germany in the early 2000s.<\/p>\n During that time, Page helped to characterize a pair of genes that some varieties of the plant uses to make fragrant oils responsible for pine- and lemon-like aromas1<\/a><\/sup>. And during an interview for a position with Canada\u2019s National Research Council (NRC), Page proposed similar projects to reveal how cannabis produces pharmaceutically active compounds known as cannabinoids.<\/p>\n He got the job, but was dismayed when he showed up to start his lab group in 2003 at the NRC\u2019s Plant Biotechnology Institute in Saskatoon, Saskatchewan. Page recalls his boss saying: \u201cYou\u2019re not going to work on cannabis here. We\u2019re the government.\u201d<\/p>\n What a difference a change in policy makes. On 17 October, Canada became the second country in the world, after Uruguay, to legalize cannabis for all uses. And although a few other countries, most notably Israel, have made a concerted effort to support agricultural research into cannabis, full legalization in Canada has brought with it unparalleled access to money for basic research on the plant.<\/p>\n Most of the country\u2019s 129 licensed cannabis producers are now clamouring to work with scientists on everything from gene mapping and metabolic engineering to optimal drying techniques and growing practices. And as part of an effort to corner the global legal cannabis market \u2014 one that\u2019s conservatively forecast to top US$57 billion within a decade \u2014 federal and provincial governments in Canada are putting up millions of dollars to support research.<\/p>\n Some researchers, such as Page (who still dabbled in cannabis research during his decade at the NRC), are well prepared to take advantage of Canada\u2019s great green rush. But botanists of all stripes are now turning to the plant, for both the funding opportunities and the uncharted science.<\/p>\n <\/p>\n <\/p>\n <\/p>\n Anandia chief executive Jonathan Page has spent much of his career trying to work on cannabis.<\/span>Credit: James MacDonald for\u00a0Nature<\/i><\/p>\n<\/figcaption><\/figure>\n <\/p>\n <\/p>\n \u201cYou\u2019re talking about a plant that\u2019s a century out of date in terms of modern breeding techniques and scientific development,\u201d says Ernest Small, a botanist with Agriculture and Agri-Food Canada in Ottawa who has studied cannabis off and on since 1971.<\/p>\n When Page first moved back to Canada 15 years ago, he initially resigned himself to studying a close relative of cannabis, the hop plant\u00a0Humulus lupulus,<\/i>\u00a0which is used in brewing beer. But he doggedly pursued avenues to keep working on pot. Page secured a licence to grow industrial hemp, a variety of cannabis cultivated for its fibre that produces only trace amounts of tetrahydrocannabinol (THC), the mind-altering chemical responsible for cannabis\u2019s high. Eventually, he hooked up with the sole company contracted at the time by the government to produce the plant for medical purposes.<\/p>\n Page unpicked the pathway that leads to the formation of THC and cannabidiol (CBD) \u2014 cannabis\u2019s other main medically important compound2<\/a><\/sup>. Together with molecular geneticist Timothy Hughes at the University of Toronto, he sequenced the genome of a potent pot variety called Purple Kush3<\/a><\/sup>. But, says Page, \u201cthe NRC was still totally unsupportive of this work\u201d. So, in late 2013, he moved to Vancouver to start a cannabis biotechnology company called Anandia Labs.<\/p>\n In one of Anandia\u2019s first projects, Page worked with Sean Myles, a population geneticist at Dalhousie University\u2019s Agricultural Campus in Truro, Canada, to genetically characterize 124 samples of cannabis4<\/a><\/sup>. The analysis showed that the commercial labelling of subtypes indica and sativa rarely matched the plants\u2019 DNA profiles. And different samples marketed under the same madcap varietal name \u2014 White Widow, for example \u2014 often turned out to have wildly divergent genetics. \u201cThis is absolutely unthinkable in any other legitimate agricultural crop,\u201d says Myles. \u201cYou can\u2019t put a Mackintosh apple on the shelf and pretend it\u2019s a Honeycrisp.\u201d<\/p>\n Despite garnering publicity for the research, Page had trouble pulling in capital. Then came the election in October 2015 of Prime Minister Justin Trudeau, who promised during his campaign to legalize cannabis. \u201cIt changed attitudes almost overnight,\u201d Page says.<\/p>\n Although the Natural Sciences and Engineering Research Council of Canada doesn\u2019t have a dedicated cannabis initiative, the agency has funded dozens of projects focused on cannabis biology and cultivation. Genome Canada and other government-backed organizations have made research funds available, too. More substantially, private investment dollars have come pouring into the country\u2019s cannabis industry (see \u2018A smoking-hot sector\u2019). Last year alone, Canadian cannabis companies raked in close to Can$2 billion (US$1.5 billion) \u2014 more than half of all the funding raised by legal cannabis firms worldwide \u2014 and the industry is on track to triple that number in 2018.<\/p>\n <\/p>\n <\/p>\n Source: Viridian capital Advisors<\/p>\n<\/figcaption><\/figure>\n <\/p>\n <\/p>\n Anandia was one of the many beneficiaries. After securing more than Can$13 million (US$10 million) in private investment, the company got snapped up earlier this year by industry heavyweight Aurora Cannabis in Edmonton, for Can$115 million. \u201cThat is a major gesture of confidence,\u201d says Cam Battley, chief corporate officer at Aurora, adding that science and innovation are key to growing \u201ca globally competitive company that will be built to last\u201d.<\/p>\n The sentiment is a relatively new one, says Michael Ravensdale, a plant pathologist who leads production at the firm CannTrust in Vaughan. \u201cScience was in short supply, but it\u2019s going to be very important for the next chapter of the cannabis industry.\u201d<\/p>\n That\u2019s why many companies investing in research are starting with the fundamentals. \u201cThere are these super basic, huge questions that need to be answered,\u201d says Greg Baute, who used to breed tomatoes at Monsanto in Woodland, California, and moved north this year to head breeding and genetics at Anandia\u2019s new research facility in Page\u2019s home town of Comox. \u201cYou can do these really straightforward experiments and get these huge results.\u201d<\/p>\n In a suburban Toronto mall, nestled alongside a paint store, sits a nondescript brick building, home to TerrAscend, a cannabis producer that has been shipping its product for about a month in anticipation of 17 October. Inside, past a barbed-wire fence and several layers of electronic security, are grow rooms full of Shishkaberry, CBD God Bud and Cold Creek Kush, cultivars valued for their sleep-inducing, antidepressant and stress-relieving properties, respectively.<\/p>\n Nearly all the plants are unpollinated females, called \u2018sinsemilla\u2019 (meaning \u2018without seed\u2019), that produce the highly potent flowering tops, or buds, rich in THC and other cannabinoids. Males, with their pollen-filled sacs, are not only superfluous \u2014 the female plants are all propagated through cuttings \u2014 but also avoided for fear of scrambling genes in an uncontrolled way.<\/p>\n Yet, TerrAscend has a small space in the back reserved for males. Back in June, the company launched a research and development arm in conjunction with scientists at two Ontario universities who will use the sequestered plants for experiments that are standard in agriculture but have rarely been done with cannabis. The scientists will mate the plants, coax them to produce seeds and then expose the seeds to chemical mutagens in the hope of finding new desirable traits \u2014 pest resistance, say, or increased tolerance to environmental stresses such as drought.<\/p>\n <\/p>\n <\/p>\n Many basic agricultural experiments have yet to be performed with cannabis.<\/span>Credit: James MacDonald for\u00a0Nature<\/i><\/p>\n <\/p>\n <\/p>\n<\/figcaption><\/figure>\n A lab technician trims and replants cannabis plants at one of Anandia\u2019s Labs in Vancouver.<\/span>Credit: James MacDonald for\u00a0Nature<\/i><\/p>\n<\/figcaption><\/figure>\n <\/p>\n <\/p>\n Scientists involved with the TerrAscend spin-off, including plant geneticists Peter McCourt and Shelley Lumba at the University of Toronto, plan to mutagenize six varieties of cannabis with the aim of obtaining improved versions of some of the company\u2019s go-to stock. \u201cOur main goal,\u201d says Lumba, \u201cis to make cannabis into a real horticultural crop.\u201d<\/p>\n Another decades-old practice for improving agricultural plants involves intentionally doubling or tripling their genomes, which tends to give plants bigger cells, larger structural features and greater yields of chemical compounds. Domesticated wheat species, for example, have 4\u20136 copies of their genome; sugar cane can have as many as 16. And although most modern farmed plants had their DNA multiplied simply through hundreds of years of cultivation, there are ways to speed up the process. All cannabis varieties characterized so far have only two sets of the genome \u2014 all, that is, except for a handful of plants growing at Canopy Growth Corporation in Smiths Falls.<\/p>\n There, plant molecular geneticist Shelley Hepworth at Carleton University in Ottawa and her former graduate student used a cell-cycle-disrupting herbicide to trigger five varieties of cannabis to double their normal chromosome count. At first blush, says Hepworth, \u201cthe plants are definitely bigger\u201d. But the scientists still need to finish their analyses to determine whether the \u2018tetraploid\u2019 cannabis lines have elevated levels of THC, CBD or other cannabinoids.<\/p>\n A more modern plant-breeding technique \u2014 one that dates back to the 1980s \u2014 is known as marker-assisted selection. It involves finding genetic signatures associated with a desirable trait \u2014 high essential-oil content, say, or automatic flowering under any light condition. Scientists can then use DNA analyses to quickly \u2018preview\u2019 which seedlings should have optimal properties instead of waiting months for the plants to mature.<\/p>\n Only a small number of markers exist for cannabis, however, in large part because few researchers have ever looked for them. One that has been described comes from George Weiblen, a plant biologist at the University of Minnesota in Saint Paul and one of the few academics in the United States who has a federal licence to grow cannabis \u2014 but he\u2019s restricted to just 50 plants at a time (see\u00a0\u2018The wide world of weed\u2019<\/a>). It took him 12 years to determine the inheritance pattern of genes that affect drug content and to identify a genetic marker linked to the THC-to-CBD ratio5<\/a><\/sup>. That\u2019s longer than it took Gregor Mendel to work out the laws of heredity, Weiblen says. \u201cOur programme is a poster child for the absurdity of cannabis research in the United States.\u201d<\/p>\n A complete cannabis genome would make it easier to identify informative DNA markers. But early efforts have yielded maps that are patchy and incomplete, says Kevin McKernan, chief science officer and founder of Medicinal Genomics in Woburn, Massachusetts, who did some of the early work. He (see\u00a0go.nature.com\/2kpzgkc<\/a>) and Page3<\/a><\/sup>released maps independently in 2011. \u201cThey\u2019re train wrecks,\u201d says McKernan. But that\u2019s changing. And thanks to an international trend toward less restrictive laws around cannabis (see \u2018A budding trend\u2019), many weed companies are now investing in genetics research.<\/p>\n <\/p>\n <\/p>\n Source: Arcview Market Research\/BDS Analytics<\/p>\n <\/p>\n <\/p>\n<\/figcaption><\/figure>\n \u201cThis year is a turning point for cannabis molecular genetics,\u201d says C. J. Schwartz, founder and chief executive of Sunrise Genetics in Fort Collins, Colorado \u2014 one of at least six companies that say they have come up with fine-scaled genome maps. They have not yet been published yet in a peer-reviewed journal, but McKernan posted a preprint of his map on 10 October6<\/a><\/sup>\u00a0and Schwartz expects to make his sequence public by the end of the month.<\/p>\n Then there are scientists who are hoping to engineer new properties into the plant. At Canopy Growth, research and development manager Katya Boudko worked with molecular biologist Douglas Johnson at the University of Ottawa to develop a gene-silencing technology that prevents expression of the THC-synthesis gene. Boudko expects plants to compensate by boosting their levels of CBD \u2014 or, she says, \u201cit could potentially produce other cannabinoids that the world doesn\u2019t even know about yet\u201d.<\/p>\n Boudko has yet to fully test this theory, however. That\u2019s because she hasn\u2019t managed to grow fully fledged plants from genetically modified tissue \u2014 and\u00a0nor have many others<\/a>. Because seeds or clippings cannot be genetically modified in a consistent and predictable way, scientists need to culture plant tissue and coax it into producing roots and shoots after the genes have been manipulated. Often, scientists can get the cellular masses to produce fine root hairs, but the shoots have proved particularly problematic.<\/p>\n In 2010, a team from the University of Mississippi in Oxford, where for 50 years researchers have grown all the cannabis used for\u00a0government-backed health studies<\/a>\u00a0in the United States, described a hormone recipe for inducing shoot formation that, it says, works more than 80% of the time7<\/a><\/sup>. Yet, others say that they can\u2019t get the protocol to work on their own varieties. \u201cThere are tens of labs that are now working on making the protocol more efficient,\u201d says Leor Eshed-Williams, a plant developmental geneticist at the\u00a0Hebrew University of Jerusalem<\/a>.<\/p>\n <\/p>\n <\/p>\n A lab technician trims and replants cannabis plants at one of Anandia\u2019s Labs in Vancouver.<\/span>Credit: James MacDonald for\u00a0Nature<\/i><\/p>\n<\/figcaption><\/figure>\n <\/p>\n <\/p>\n For many in the industry, however, any suggestion of genetic modification is an anathema. Besides, says Ethan Russo, director of research and development at the International Cannabis and Cannabinoids Institute in Prague, \u201cthis plant is so malleable that a lot of these genetic modifications are really unnecessary\u201d. Modern selective-breeding strategies, he argues, should suffice \u2014 and those methods needn\u2019t require genetic markers. In collaboration with Mark Lewis, president of Napro Research in Westlake Village, California, Russo has used chemical profiling to create dozens of cannabis varieties with unique properties and elevated yields8<\/a><\/sup>.<\/p>\n Elsewhere, researchers are looking to control and fine-tune environmental conditions at various stages of the growth cycle. Such tweaks could prove important for maximizing profits from costly indoor growing operations that are a major source of high-end cannabis in Canada. At CannTx Life Sciences in Puslinch, operations head Jeff Scanlon and his colleagues developed a system for air circulation.<\/p>\n Scanlon showed that the fans found in most companies\u2019 grow rooms move air over the plant crowns. But in the thicket of leaves and branches beneath, the air remains stagnant, leading to pockets of elevated temperature and humidity that breed fungal pathogens. The solution: a pressure gradient from floor to ceiling that ensures airflow along every surface of the plant. \u201cIt\u2019s a very simple innovation,\u201d Scanlon says.<\/p>\n Deron Caplan, director of plant science at Flowr in Lake Country, completed a PhD this year in which he systematically determined optimal rates of fertilizer supply at various stages of cannabis production9<\/a><\/sup>,<\/sup>10<\/a><\/sup>\u00a0and best practices for propagating the plant clonally through cuttings11<\/a><\/sup>. \u201cIt\u2019s very crude, incremental advancements that we\u2019re making,\u201d says Mike Dixon, an agricultural scientist at the University of Guelph and one of Caplan\u2019s graduate advisers. But it\u2019s slowly helping to phase out the homespun practices that persist throughout much of the industry, he says \u2014 \u201cwhat I kindly refer to as anecdotal bullshit\u201d.<\/p>\n Some of the holdovers of illegal cultivation are on display at Beleave, a cannabis producer in Hamilton, where master grower Shane Whelan-Stubbs has persevered with some practices for 20 years, first in a bedroom cupboard, then in basements, warehouses and now a legitimate business. Whelan-Stubbs is open to the science, and Beleave will soon start collaborating with a team at Guelph, where scientists hope to open the country\u2019s first dedicated academic centre for cannabis research some time next year. Still, Whelan-Stubbs continues to water his plants by hand. \u201cThe plants, at the end of the day, need love,\u201d he says.<\/p>\n Page would argue that they also need science. But the burgeoning research that he\u2019s been a part of likewise would have long ago withered without cannabis at its centre. \u201cWe think of it in many ways as a drug or a pharmaceutical,\u201d he says, \u201cbut can\u2019t forget that it\u2019s the plant that\u2019s at the heart of this revolution. It all comes down to a plant.\u201d<\/p>\n <\/p>\n <\/p>\n<\/div>\n Nature<\/span>\u00a0562<\/strong>, 327-330 (2018)<\/p>\n <\/p>\n <\/p>\nIsrael<\/h6>\n
United States<\/h6>\n
Uruguay<\/h6>\n
Colombia<\/h6>\n
What legal weed in Canada means for science<\/h4>\n
Opportunities abound to improve the cultivation of a once-forbidden plant.<\/h5>\n
![\"Cannabis](\"https:\/\/media.nature.com\/w700\/magazine-assets\/d41586-018-07037-1\/d41586-018-07037-1_16202112.jpg\")
<\/picture>\n![\"Jonathan](\"\/\/media.nature.com\/w800\/magazine-assets\/d41586-018-07037-1\/d41586-018-07037-1_16202118.jpg\")
<\/div>\n<\/div>Research blunted<\/h6>\n
![\"\"](\"\/\/media.nature.com\/w800\/magazine-assets\/d41586-018-07037-1\/d41586-018-07037-1_16202420.png\")
<\/div>\n<\/div>Joint venture<\/h6>\n
![\"Cannabis](\"\/\/media.nature.com\/w800\/magazine-assets\/d41586-018-07037-1\/d41586-018-07037-1_16202120.jpg\")
<\/div>\n<\/div>![\"\"](\"http:\/\/163.180.4.222\/lab\/wp-content\/uploads\/2018\/10\/d41586-018-07037-1_16202122-300x169.gif\")
<\/div>\n<\/div>![\"\"](\"\/\/media.nature.com\/w800\/magazine-assets\/d41586-018-07037-1\/d41586-018-07037-1_16202340.png\")
<\/div>\n<\/div>Dank DNA<\/h6>\n
![\"Cannabis](\"\/\/media.nature.com\/w800\/magazine-assets\/d41586-018-07037-1\/d41586-018-07037-1_16202124.jpg\")
<\/div>\n<\/div>Hashing out the basics<\/h6>\n