This yr, for the primary time in my life, I’ll be internet hosting my household for the vacations. And to their deep disgruntlement, we’ll be celebrating it with no Christmas tree. No, this isn’t some principled stance in opposition to the yuletide-industrial advanced or a private entrance within the battle on Christmas. I’m simply far more thinking about an indoor evergreen interloper when its needles fall in another person’s residence. Now, below cautious watch and watering, most firs, spruces, and pines can preserve their aromatic greenery for weeks, if not months. Somebody like me, who excels at neither of these issues, wants a tree that may maintain on to its needles—and its dignity—with out an oz. of effort in repairs.
An excessive amount of to ask, you say? Perhaps a decade in the past. However with as we speak’s sequencing and computational biology instruments, you could by no means get caught with a tragic Charlie Brown specimen once more. In truth, at this very second, scientists are sifting via 1,200 gigabytes of genetic information, taken from a whole bunch of Christmas bushes rising all around the world, to determine what separates one of the best needle-holders from the worst. They’re additionally searching for the genetic alerts that confer resistance to devastating molds from the genus Phytophtora, Greek for “plant destroyer.” Though some fungicides can cut back its severity, the basis rot nonetheless prices the US Christmas tree business a whole bunch of hundreds of thousands of every year.
In contrast to America’s other commercial crops, little or no is understood about what goes on inside a Christmas tree’s genome. For hundreds of years growers have needed to rely solely on conventional strategies of choosing and breeding for fascinating traits. However quickly, because of a small cadre of scientists who’ve devoted their careers to unraveling the conifers’ secrets and techniques, they’ll be capable of use genetics to make a extra excellent Christmas tree. One possibly even I might need in my condominium.
Gary Chastagner has spent each fall since 1978 operating reconnaissance at Christmas tree plantations, pop-up retail tons, and big-box shops throughout the nation. At every cease, the plant pathologist scours the stock, discovering the best-looking tree in the entire place. Then he takes images, interrogates salespeople, and snips away small branches, which he weighs with a transportable scale earlier than airfreighting them again to Puyallup, for testing at his Washington State University lab.
Within the outdated days, that meant having a military of grad college students marking a 2-inch phase on every department and counting each needle or needle scar in that space. At the moment, Chastagner’s workforce hangs the branches on racks or wire clotheslines strung throughout a temperature-controlled concrete cistern, the place they relaxation with out water for seven to 10 days. Then, a couple of well-trained technicians gently rub every department and charge the needle retention on a scale of 1 (1 % of needles fall off) to seven (91 to 100 % loss).
Chastagner is just within the extremes on each side of the spectrum. Over time, he’s taken any cuttings that charge zero to 1, or six to seven and grafted little bits of them onto rootstocks his lab manages on 15 acres in Puyallup. This course of converts every outlying specimen into an remoted stand of genetically an identical bushes, preserving their distinctive DNA in what’s known as a clonal holding block.
Now, these bushes are a part of a large effort to pinpoint the tiny genetic variations that decide why some bushes prove higher than others. 5 years in the past, Chastagner and his analysis companions at North Carolina State College landed $1.three million from the US Division of Agriculture—the most important Christmas tree grant in US historical past—to make use of RNA, which interprets DNA into proteins, to determine which genes are turned on or off in bushes with beneficial traits. And in just a little greater than a month, they’ll lastly have these solutions.
That’s how lengthy Jill Wegrzyn, a computational biologist on the College of Connecticut, expects it’s going to take to investigate all of the sequencing information—5 years’ value, collected by Chastagner and his collaborator at NCSU, John Frampton. “Now we have our record of genes we’re taking a look at to see if they’re being up or downregulated,” says Wegrzyn. “Now we’re connecting them collectively, to see how they type completely different networks and pathways of gene expression. Which isn’t tremendous simple for conifers.”
That’s as a result of the conifer genome isn’t just huge—20 billion base pairs in comparison with your three billion—but additionally fairly bizarre. Sooner or later of their deep previous, spruces, pines, firs, and their family acquired a whole second set of genes. Scientists suppose this genome-wide duplication probably helped form these species into the tallest, hardiest crops on the planet. But it surely’s additionally made sequencing them an extremely daunting problem. And in contrast to corn and soybean, there hasn’t been a lot cash out there to even attempt. Thus far scientists have managed to place collectively partial DNA blueprints for less than a handful of conifers, not together with the preferred Christmas tree species.
Chastagner isn’t after something so grand. What he cares about is what’s happening in a particular layer of cells, proper the place the needle meets the department. Gene expression right here controls whether or not or not these cells break open, inflicting the tree to launch its needles. So his workforce scraped these cells out of a whole bunch of branches, at 10, 20 and 30 days post-harvest. Then they froze the tissue in liquid nitrogen and despatched them off to North Carolina to be extracted for RNA sequencing.
Every pattern is sort of a snapshot of all of the genes being turned on and off as needles are misplaced. Chastagner’s colleagues at NCSU despatched in samples taken from the roots of bushes, to see how gene expression in several bushes modified in response to fungal infections. Now it’s Wegrzyn’s job to type via all of them to search for genetic signatures that correspond to needle retention and phytophtora resistance.
The objective, on the finish of all this, is to discover a molecular biomarker for needle retention. In order that Christmas tree growers can separate the sturdy, stoic ones from the remainder of the pack a lot sooner. It takes a yr or two to develop a viable seedling in a nursery and one other six to eight earlier than you possibly can inform if it’s an excellent one—that’s, if it survives the rampant root rot. With biomarkers, growers may check a lot earlier, solely planting bushes that can preserve their needles post-harvest. And it may assist breeders cross in resistance traits from extra unique species to extra conventional American ones.
This doesn’t imply Christmas bushes are going GMHo-ho-ho anytime quickly, although. Makes an attempt to genetically engineer designer bushes—for tremendous perfume, or bioluminescence, say—have never really gotten off the ground. And even with new work into conifer genetics, there’s nonetheless not sufficient information to make the bushes good candidates for as we speak’s newer gene modifying applied sciences. “The potential for genetic enchancment in these species is big,” says Chastagner. “However the actuality is that the appliance of these enhancements utilizing genetic engineering can be hampered by their complexity—that simply slows all the pieces down.”
So it might be some time earlier than I can purchase the proper, vacuum-free Christmas tree. Alternatively, it would take me that lengthy to persuade my household to let me host one other vacation.