Oh genetically modified tree, thy leaves are ever changing


In the coniferous battle between real and artificial Christmas trees, there is common ground in the less-than-green environmental impact of both seasonal industries.  To keep up with the annual demand of trees, Oregon, the top producer of Christmas trees in the United States, provided 6.4 million trees in 2012 alone, and many of their and other commercial farms throughout the nation require the regular use of chemical fertilizers to replenish nutrients in soil [1].  Since the roots of firs and other popular Christmas tree choices are prone to infection by pathogens, the grounds of tree farms are often fumigated with methyl bromide and chloropicrin to prevent infections by pathogens and to limit the growth of weeds, which heightens the risk of chemical runoff into nearby water sources.  However, manufacturing PVC needles, steel branches, and emission of pollutants during the production and disposal of artificial trees render it an unfit alternative to the real Christmas tree [2].  In New York City, whereas the city park’s department provides a mulching and compost service for old Christmas trees after the holiday passes, most artificial trees--which are made up of plastic and metal and cannot be recycled--are likely to end up in a landfill.

Proponents of real Christmas trees are adamant that their trees will be a force of longevity.  At the forefront of innovation to engage the billion-dollar Christmas tree industry, Christmas tree scientists apply their knowledge of genetics and plant development to select ideal trees for the holidays.  John Frampton, a professor and Christmas tree geneticist in the Department of Forestry and Environmental Resources at North Carolina State University, has years of expertise in the genetics and breeding of trees [3].  Much of his work has been interested in studying the genetic resistance of seedlings to harmful agents in the soil like pathogenic molds, which would harm the development of the prospective Christmas tree [4].  Frampton and his colleagues in the Christmas tree field are principally interested in something called “tree improvement,” or the use of genetics to increase the commercial value of trees from farms, commercial or private.  For Gary Chastagner, a professor of plant pathology at Washington State University who is sometimes known as “Mr. Christmas Tree,” the wealth of this matter is in the needles of the tree [5].  One measure of needles, the Denmark Needle Retention Scale, was developed by Chastagner and his Danish colleagues to evaluate just how fresh or dry the trees will stay after it’s cut [6].  Because Noble and Fraser firs are better at retaining moisture in their needles, they make a superior brand of tree and are often referred to as the “Cadillac of Christmas trees.”  But for other trees, after a few weeks in the stand, “there will be absolutely no needles left on some branches,” Chastagner told a reporter from the Seattle Times, “you don’t want to be growing too many of those.”  [7]

Using RNA sequencing and other high-throughput sequencing methods, Chastagner’s hope is to identify the genes and markers that lead to superior trees.  Jill Wegrzyn, a professor in the Department of Ecology and Evolutionary Biology at the University of Connecticut, is one of the many scientists who curates databases like TreeGenes, which uses big data to help other ecological scientists understand how a forest’s biodiversity is changing over time [8].  With interest to the Christmas tree industry, Wegrzyn and Frampton have formed a collaboration to determine the associations of genes that control traits such as needle retention or the resistance to pathogens [9].  Even as development in genetic research advances, there’s a significant chance that the Christmas tree you have in your home was already chosen for farming due to selective breeding considerations for genetic characteristics like needle softness, fragrance, and needle retention, as exemplified by Fraser and Balsam firs [5].  One salient hope should be that as knowledge of genetic modification of trees progresses, scientists will also be able to genetically modify a tree that is less taxing on natural resources like water, or that needs less pesticide treatment, in both cases lowering the environmental impact of growing real trees.  

However, the fact that scientists are looking to optimize current trees through genetic selection is just the beginning.

Alexander Krichevsky and his colleagues published an article in PLOS ONE in 2010, where they generated the first autonomously luminescent plant using the luciferase (a gene from fireflies) pathway [10].  A few years later, Krichevsky designed a plant called ‘Starlight Avatar’ for the company he founded called BioGlow Tech (now GLEAUX) by splicing genes from the chloroplast genome and a common potted plant.  One interesting application of this tree lighting technology that’s already being considered is to illuminate streets with glowing trees rather than lamps, one notable example being the London’s Garden Bridge project [11].  But with holidays right around the corner, why stop there?  Using a similar luciferase-based system of illumination, Katy Presland and group of postgraduate students at the University of Hertfordshire proposed a project in 1999 to modify a Douglas spruce by infecting seedlings with a bacterium that encoded genes for GFP (green fluorescent protein) and luciferase [12].  In order to activate luciferase, which would switch on the GFP molecule and enable the spruces to glow, an activating luciferin-containing fertilizer would be sold along with the tree.  Although this specific project has fallen off the map, hope for this otherwise innovative and exciting biotech idea has resurfaced. GLEAUX recently noted on their website that “The #future is #merryandbright with #bioluminescence,” on a Christmas tree-themed post [13].  Today our trees are genetically selected, pathogenically resistant, and pleasantly triangular due to scientific intervention.  Tomorrow, they might just glow and save us on our electricity bills as well.   For the Christmas tree industry, the future is looking very bright.



1. http://www.mdpi.com/1999-4907/5/10/2581/htm

2. http://www.christmastrees-wi.org/LCA%20Christmas%20Tree-ellipsos.pdf

3. http://www.popsci.com/science/article/2012-12/how-science-perfecting-real-christmas-trees

4. http://link.springer.com/article/10.1007/s13595-012-0205-4

5. http://www.nytimes.com/2012/12/06/garden/building-a-better-christmas-tree.html

6. https://blog.23andme.com/23andme-and-you/genetics-101/the-genetics-of-your-christmas-tree/

7. http://www.seattletimes.com/seattle-news/wsu-professor-uses-genetics-to-build-a-better-christmas-tree/

8. http://clas.uconn.edu/2014/12/13/big-data-and-the-science-of-the-christmas-tree/

9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4866652/

10. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0015461

11. http://www.dailymail.co.uk/sciencetech/article-2593328/End-street-lamp-Avatar-style-glowing-trees-inspired-fireflies-soon-light-night-skies.html

12. http://news.bbc.co.uk/2/hi/science/nature/484809.stm

13. http://gleaux.us/welcome-to-gleaux/