Hort couture or hubris? The growing trend of genetically engineered novelty plants

A few months ago I wrote about the newly released Purple Tomato, one of the first direct-to-consumer genetically engineered plants made available to the general public. (I’m happy to report that my Purple Tomato seedlings are growing along quite well.) Shortly after I wrote that article, I learned about another new genetically engineered plant being released to home gardeners, this time a bioluminescent petunia. So, of course you know I just had to have some.

The Firefly Petunia was released recently from Light Bio, a company based in Idaho.  The company states that they grew out 50,000 plants for initial sale, but have worked with third-party growers to grow out additional plants from cuttings due to high demand for the plants.

The petunia itself is pretty nondescript. It is a small-flowered, white variety that wouldn’t get a second glance at a garden center. But the company introduced a set of genes from a bioluminescent mushroom called Neonothopanus nambi  that make the faster growing parts of the plants (mainly flowers, but also other growing points) glow. The glowing is caused by a reaction between enzymes and a class of chemicals called, funnily enough, luciferins. And this is bioluminescence – it glows all the time in the dark. It isn’t like a “glow in the dark” where they have to charge up with a light source and only glow for so long.

How a mushroom gets its glow
Neonothopanus nambi daytime look to night time look Source: Science News

Just like the petunia, the fungus is pretty nondescript during the daytime, but glows brightly once darkness descends. I’ve seen glowing fungus once in my life. As a kid I once saw what is called Foxfire, a glowing fungus on some decaying logs. It is pretty cool seeing something glowing so eerily in nature. Now, I have that same glow in my garden.

Back to the plants. The plants are a bit of investment, ringing in at $29 per plant plus shipping, but there are some price breaks at higher quantities if you order several or put together a group order. As a startup, I suppose the company is banking on the novelty of the plant to demand such a high price to cover costs. According to several sources, these white petunias are just the start. They’re working on roses, houseplants and more.

But why glowing petunias?

Before I placed my order, I had to take a step back and think about why. Why a glowing petunia? With the tomato there is at least the case of increased health properties with added anthocyanins. But what is a value of a glowing petunia other than a novelty? Is there a purpose? Or is it just hubris? And why are there genetically engineered plants on the market all of a sudden?

While the petunias don’t have a culinary or health value, the value that they bring is one of acceptance and familiarity. For decades now, well organized and funded campaigns have spread fear of genetic engineering. Seed companies embraced “Non-GMO” as a marketing scare tactic to drive up sales due to a fake boogie man. And even bottled water and salt are labeled as “Non-GMO”. But it seems that the tide of public opinion seems like it might be turning.

Seeing the excitement around both the Purple Tomato and this bioluminescent petunia seems to show a growing interest, or at least a waning of distrust, in genetically engineered plants. And It think that is one of the benefits, or maybe the causes, of seeing genetically engineered plants on the market. Researchers have found that the online conversation about genetically engineered organisms seems to be shifting – from less polarized to increasingly favorable.

While there are sill some hiccups and some ethical and environmental issues, most scientists see genetic engineering as the most important tool in addressing issues such as endemic plant diseases affecting staple crops and developing plants that can withstand warmer and drier conditions as the climate changes. In order for us to be able to fully use these tools, the conversation needs to continue to shift to a more favorable position.

Starting off with tomatoes, petunias, and other flowers is also a choice of ease. Growing plants that don’t have native counterparts where there could be unintentional spread of genes in the wild reduces some of the regulatory hurdles plants face in the United States. And while the purple genes introduced into tomatoes could spread to plants in the food supply, the safety risk is minimal. It would be much harder to get approval for, say, a genetically engineered sunflower or coneflower where there are wild-growing natives into which the glowing genes could inadvertently spread.

Why are genetically engineered plants popping up all of a sudden?

Probably one of the reasons we are seeing so many new genetic engineering projects now is that it is so much easier. With the discovery of CRISPR-Cas9 technology, it is much easier for scientists to transform plants with DNA insertions or extractions. This technology has revolutionized the world of genetics and genetic engineering not only in the plant world, but also in the areas of human health and more.

Before CRISPR, there were a few methods of introducing DNA into organisms. The most common one for plants was probably using a plasmid from the bacterium Agrobacterium tumefasciens. This is the cause of crown gall and it works by inserting its own ring of DNA, called a plasmid, into the DNA of the plant. The plant then produces proteins based on the virulent DNA and also replicates the DNA. One of the common method was bombardment, putting the DNA on tiny microscopic beads, usually gold, and shooting them into the tissue. Tobacco mosaic virus was also used for plant genetic transformations, especially in related plants such as tobacco, tomato, and…..petunia. Most of the work I did in undergrad was with the commonly used with model plant Arabidopsis thaliana (mouse-ear cress).

The transformation, or success, rates for these methods was relatively low compared to CRISPR. Plus, where the DNA ended up was random. There was no control over where the new snippets of DNA ended up, or what genes they would disrupt, or knock-out, in the process. I did quite a bit of research as an undergrad on figuring out just what genes were knocked out in certain transformations and what that changed in their physiology or response to stimuli (our research focus was gravitropism and response to red light).

CRISPR has taken away the guessing game from genetic transformations. Scientists can now target exactly where they want genes to be inserted, or in some cases “knocked out” or interrupted so they are not expressed. For example, Arctic Apples were developed by knocking out the gene in apples that makes polyphenol oxidase, the enzyme that causes them to turn brown after cutting. This has created a technology that has the potential to substantially reduce food waste in crops that have similar reactions as well, such as potato.

So I think the trend of genetically engineered plants for consumers will continue to grow. Evolving from novelty plants to plants that serve a higher purposes, such as nutritional value enhancements, climate change resistance, and more. It will take us a while to get there, but as the technology advances so does, it seems, public opinion. Until then, I’ll just enjoy my glowing petunias and purple tomatoes.

Additional Sources

https://www.scientificamerican.com/article/this-genetically-engineered-petunia-glows-in-the-dark-and-could-be-yours-for-29/

https://www.science.org/content/article/mushrooms-give-plants-green-light-glow

https://www.fastcompany.com/91073850/glow-in-the-dark-petunias-are-just-the-beginning

Underrated Beneficial Arthropods Part 3: Nutrient Cyclers

For the third and final installment of the Underrated Beneficial Arthropods series, I will be talking about a group of organisms that is arguably one of the least recognized and most underappreciated when it comes to beneficials. Often doing most of their work ‘behind the scenes’ the nutrient cyclers, more familiarly referred to as decomposers or saprophytes, play a crucial role in our landscapes, one that is equally as important as that of pollinators and natural enemies. Although one of the more famous examples of nutrient cyclers that many gardeners are fond of are earthworms, since these are not arthropods I will not be focusing on them in this post. (I am, however, planning on dedicating an entire post specifically to earthworms, so stay tuned for that).

According to Galente and Marcos-Garcia, 90% of the organic matter produced by green plants in terrestrial ecosystems is not consumed. The arthropods in this category provide essential ecosystem services by breaking down materials such as waste, dead plants and animals and redistributing nutrients in the soil and making them available to the plants and other primary producers (which is why they are referred to as ‘nutrient cyclers’). Although it’s not a very glamorous job nutrient cycling is essential to a well-functioning ecosystem, without which, the earth would be covered in dead plants and animals.

Dung Beetles. Photo: Whitney Cranshaw, Colorado State University, Bugwood.org

Like the previous posts in this series, I will be organizing this post by group of arthropods, and highlighting some of the most notable examples of nutrient cyclers in each group. This will not be an exhaustive list of all the nutrient cycling arthropods but I will include resources at the end if you want to continue to explore this topic further.

Beetles

Containing dead plant, dung and carrion (decaying animals) feeding groups, beetles (Order: Coleoptera) run the gamut of nutrient cycling roles. Some of the most well-known in this group include the charismatic black and yellow or orange carrion beetles and burying beetles (Family: Silphidae) who bury small animal carcasses into the soil, lay their eggs on them, and allow their larvae to feed on the carcasses.

American Carrion Beetle (Necrophila americana). Photo: Abiya Saeed

Other well-known decomposers in this group include dung beetles (Family: Scarabaeidae) which consume the feces of other animals. Due to the fact that these dung beetles process a significant amount of cattle dung and contribute greatly to the reduction of fouled forage from the accumulation of dung in livestock landscapes, Losey and Vaughan (2006) estimated the financial value of this reduction of forage fouling to be $122 million. They also play a significant role in reducing the amount of nitrogen lost to the atmosphere if dung was left on the surface to dry. By burying this dung the nitrogen is integrated into the soil making it available to plants. Sap beetles (Family: Nitidulidae) are just one example of beetles that feed on a variety of overripe, damaged, or decomposing fruit and vegetation (which may be a context that many gardeners would see them in). There are also several other beetles that shred dead vegetation such as leaflitter, bore into wood, and help create the layer of organic matter (humus) on the soil surface.

Burying Beetle (Nicrophorus investigator). Photo: Joseph Berger, Bugwood.org

Flies

Flies (Order: Diptera) also contain all the categories of nutrient cyclers- from carrion feeding to decaying vegetation and waste. Some of the most famous flies in this category are the ones that play an important role in decomposing carcasses and, as such, are important in forensic entomology. Blow flies (Family: Calliphoridae) and flesh flies (Family: Sarcophagidae) are two of the most important forensic fly families. Phorid flies (Family: Phoridae) feed on a variety of decaying plants and animals. Crane fly (Family: Tipulidae) aquatic larvae are also well-known decomposers that feed on decaying vegetation and leaf debris. Although a few species of fruit flies (Family: Drosophilidae and Tephritidae) can be important agricultural pests, other species in this group feed primarily on rotting fruit. When indoors many of these groups of flies can be a nuisance and also transmit bacteria from the surfaces on which they were feeding so controlling them in indoors is often important.

Blow Fly (Family: Calliphoridae). Photo: Susan Ellis, Bugwood.org

Cockroaches

Cockroaches (Order: Blattodea) often get painted with a broad brush as ‘pests or vermin’, however of the approximately 4000 species of cockroaches in the world less than 1% are considered pests of any kind. As omnivores, cockroaches can feed on a variety of materials, but many within this group are detritivores (feeding on decaying vegetation). Most of these beneficial species of cockroaches are found in leaflitter and moist areas with rich organic matter outdoors and are rarely going to enter your house, and if they do happen to get inside are only considered a minor nuisance. A well-known group of these decomposers is referred to as wood cockroaches or wood roaches.

Wood roach (Parcoblatta spp.). Photo: Kansas Department of Agriculture , Bugwood.org

Termites

Formerly in their own order (Isoptera), termites now belong to the same order as cockroaches (Blattodea) due to molecular evidence that indicates that they may have evolved from within the lineage of cockroaches. Like their cockroach relatives, these organisms often have a negative reputation since a few species of termites can be major structural pests with a significant economic impact. That being said, less than 10% of the over 2750 species of termites have been recorded as pests. The rest of this group can have significant benefits due to their feeding biology. Termites are one of the few animals that can break down cellulose (due to symbiotic associations with microorganisms in their gut) which plays an important role in helping to decompose dead woody vegetation, especially in the tropics where termites are also most abundant.  

Eastern subterranean termite (Reticulitermes flavipes). Photo: Phil Sloderbeck, Kansas State University, Bugwood.org

Springtails

Globular springtail (Sminthurus spp.). Photo: Joseph Berger, Bugwood.org

Springtails (Order: Collembola) are a group of impossibly adorable hexapods (six-legged organisms) but they are not considered insects. These tiny critters are found in moist environments and feed on decaying organic matter, decomposing plant materials, and fungi. They are called springtails because many in this group have a forked structure (furcula) folded under their abdomen that they can deploy to flick them upwards. If you haven’t yet seen this in action, I would strongly encourage you to check out some of the awesome YouTube videos that showcase this very cool function. These organisms are harmless to people and pets, and can easily be managed in indoor settings by reducing the moisture. Some of the most famous springtails include snow fleas which are noticeable tiny creatures aggregating on top of snow on warm sunny days.

Springtails (Entomobrya unostrigata). Photo: Joseph Berger, Bugwood.org

Isopods

Isopods (Order: Isopoda) are an order of Crustaceans that contain both aquatic and terrestrial organisms called woodlice. Of the nearly 10,000 species found worldwide about half of them are terrestrial. More affectionately referred to as pill bugs or roly-poly bugs (due to the fact that many can roll into a ball when disturbed), every child and adult has likely experienced these land isopods in an outdoor setting. They can be found in moist and dark environments such as under logs, rocks, and leaflitter. Like termites, Isopods also have symbiotic microorganisms which allow them to digest cellulose. As they break down decaying vegetation, they help improve soil quality, and make nutrients available for plant growth.

Pillbug (Order: Isopoda). Photo: David Cappaert, Bugwood.org

Millipedes

Millipedes (Class: Diplopoda) are a familiar and easily recognizable garden companion for a lot of us. These many-legged arthropods can be distinguished from their carnivorous cousins (Centipedes, Class: Chilopoda) by the number of legs per body segment. Where centipedes have 1 pair of legs per body segment, millipedes have 2 pairs (4 legs) per segment. Unlike their name suggests, they do not have 1000 legs, but a majority of the nearly 10,000 estimated species of millipedes fall within the range of 40 to 400 legs. Like many nutrient cyclers, they are found in damp environments where they feed on decaying vegetation and are important in making nutrients available to primary producers in the landscape.

American Giant Millipede (Narceus americanus). Photo: Abiya Saeed

Mites

Mites (Subclass: Acari) contain a variety of organisms that include predators and decomposers. The estimated 50,000 species of mites worldwide are fairly understudied with scientists pointing towards a potential million species that have yet to be described in this group. Oribatid mites (Order: Oribatida) in particular are key detritivores found in the top layers of soil. According to a SARE publication, they are so abundant, that a 100 gram sample of soil can contain as many as 500 individuals within 100 different genera. In fact, one of my first arthropod-related jobs was working as a lab technician on a subarctic soil mite biodiversity study where I had to sift through soil samples and photograph thousands of these nearly microscopic mites. These tiny ‘microarthropods’ are critical in breaking down leaflitter into smaller pieces which can then be further decomposed by smaller organisms. They also stimulate microbial activity by dispersing bacteria and fungi, which plays a very significant role in soil turnover.

Oribatid Mite. Photo: S.E. Thorpe.

There are many other groups of decomposers that can be found in a variety of different arthropod classes and orders but, unfortunately, the information on this topic is not as easy to find as that on pollinators and natural enemies. Although it is not a very glamorous job nutrient cyclers are critical in maintaining a healthy ecosystem by breaking down waste (such as feces, carcasses, and dead vegetation) and improving soil structure, function, and nutrient availability either directly or indirectly through their various biological functions. I hope you enjoyed learning about them as much as I did, and I especially hope that you will consider the various roles that arthropods play within their ecosystems the next time you see a familiar or unfamiliar critter in your gardens.

Resources:

Losey, J. E., & Vaughan, M. (2006). The economic value of ecological services provided by insects. Bioscience, 56(4), 311-323.
https://academic.oup.com/bioscience/article/56/4/311/229003

Decomposer insects (By: Galente and Marcos-Garcia):
https://entnemdept.ufl.edu/capinera/eny5236/pest1/content/03/2_decomposers.pdf

Burying Beetles:
https://entomology.umn.edu/burying-beetles

Dung Beetles:
https://extension.umaine.edu/blueberries/factsheets/insects/194-beneficial-insect-series-3-dung-beetles/

Sap Beetles:
https://extension.umn.edu/yard-and-garden-insects/sap-beetles

Blow Flies and Flesh Flies:
https://yardandgarden.extension.iastate.edu/encyclopedia/blow-and-flesh-flies

Wood cockroaches:
https://extension.psu.edu/wood-cockroaches

Springtails:
https://mdc.mo.gov/discover-nature/field-guide/springtails

Isopods:
https://mdc.mo.gov/discover-nature/field-guide/pillbugs-sowbugs-land-isopods

Millipedes:
https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=2345&context=extension_curall

Oribatid Mites:
https://www.sare.org/publications/farming-with-soil-life/mesofauna-arthropods/

People and Plants

It’s time for our Spring edition of People and Plants. This time we’ll be taking a look at the life and accomplishments of Asa Gray.

Asa Gray in 1864
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Asa Gray (November 18, 1810 – January 30, 1888), now considered the most important American botanist of the 19th century, had very humble beginnings. He was born in the back of his father’s tannery in Sauquoit, New York, the eldest of eight children. From childhood Asa was an avid reader. After completing grammar school in 1825 he attended the Fairfield Academy in Herkimer Co., New York and then went on to the Fairfield Medical College in 1826. It was then he began mounting botanical specimens. He got his medical degree and did eventually open a practise in Bridgewater, New York but never really “made a go of it”, he enjoyed botany much more. So much more that in the fall of 1831 he basically gave up his medical practise to devote more time to the study of plants.

By 1832 he was trading specimens with botanists not only in America but also in the Pacific Islands, Asia and Europe.
In early 1836 he became curator and librarian at the Lyceum of Natural History in New York, now called the New York Academy of Sciences, he resigned in 1837. In 1838 he took a position at the newly established University of Michigan as the Appointed Professor of Botany and Zoology. This position was the first devoted solely to botany at any educational institution in America. He was soon dispatched to Europe to purchase books to start the university’s library and for equipment, such as microscopes, to aid research. He spent a year traveling around Europe, visiting gardens and meeting important botanists of the day including William Hooker in Glasgow, Jospeh Descaisne in Paris, Stephan Endlicher in Vienna, and Augustin Pyramus de Candolle in Geneva. He returned to the USA in 1841.
Some trip, eh?

Gray in 1841
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While he was in Paris at the Jardin des Plantes Gray came across an unnamed dried specimen, collected by André Michaux, and named it Shortia galacifolia. Over the next 38 years he spent considerable effort looking for a specimen in the wild. The first expedition in the summer of 1841 to an area in Ashe Co., North Carolina was unsuccessful. Further expeditions yielded the same negative results. In May 1877 a North Carolina herb collector found a plant he couldn’t identify. It was collected and sent to Joseph Whipple Congdon who contacted Gray telling him that he felt he’d found Shortia. Gray was thrilled to confirm this when he saw the specimen in October 1878. In spring 1879 Gray led an expedition to the spot where S. galacifolia had been found. Unfortunately, and much to his disappointment, Gray never saw the wild species in bloom.

Shortia galacifolia – 2013. Photographed in Oconee County, South Carolina.
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In 1841 Gray was elected to the American Academy of Arts and Sciences. In 1842 he accepted the offer of a position at Harvard University. It included a salary of $1,000/year, teaching only botany, and being the superintendent of Harvard’s botanic garden. Though the salary was low the position allowed him plenty of time to do research and work in the garden. He was only 32.
At the time he had a priceless collection of more than 200,000 preserved plants, many of which he named as new species, and 2,000 botanical texts, which he donated to Harvard to found its botany department.

Asa Gray, the early years at Harvard
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In the summer of 1844 Gray moved into what became known as the Asa Gray House in the Botanic Garden. As an academic, Gray was considered a weak lecturer but was highly regarded by his peers for his expert knowledge. He was better suited to teaching advanced rather than introductory classes, which he found tedious.
He eventually became well known by the outside of academia for his prolific writings and textbooks.

Asa Gray House

His first book, The Elements of Botany was published in 1836. In it Gray championed the idea that botany was useful not only to medicine, but also for farmers. His next work Flora of North America, co-authored with John Torrey, was published in 1938.
By the mid-1850s he had become so well-known that he wrote two high school-level texts in the late 1850s: First Lessons in Botany and Vegetable Physiology (1857) and How Plants Grow: A Simple Introduction to Structural Botany (1858). The publishers pressured Gray to make these two books non-technical enough so high school students and non-scientists could understand them.
A prolific writer, he was instrumental in unifying the taxonomy of North American plants. The most popular book was his Manual of the Botany of the Northern United States, from New England to Wisconsin and South to Ohio and Pennsylvania Inclusive, known today simply as Gray’s Manual. Gray was the sole author of the first five editions of the book and co-author of the sixth, with botanical illustrations by Isaac Sprague. Many editions have been published and it remains a standard in the field. 

Illustration from Gray’s Manual of the Botany of the Northern United States

Gray also worked extensively on a phenomenon called the “Asa Gray disjunction” which is the surprising morphological similarities between many eastern Asian and eastern North American plants.

Before 1840 Gray’s knowledge of Western US plants was limited to specimens sent him by collectors and colleagues working in the field. He worked with George Engelmann, Ferdinand Lindheimer, and Charles Wright who all collected widely in the Southwest including Texas, New Mexico, and parts of northern Mexico.
Accompanied by his wife, Gray finally traveled to the American West on two separate occasions, the first by train in 1872  and then again in 1877. Both times his goal was botanical research and sample collection to take back to Harvard. His collecting companion on these trips was Jospeh Dalton Hooker, son of William Hooker whom Gray had met in Glasgow on his first trip to Europe in 1838. Gray’s and Hooker’s research was reported in their joint 1880 publication, “The Vegetation of the Rocky Mountain Region and a Comparison with that of Other Parts of the World,” which appeared in volume six of Hayden’s Bulletin of the United States Geological and Geophysical Survey of the Territories.

Asa died in January of 1888 after suffering a stroke two months prior.

Aesculus discolor by Gray, from Plates Prepared between the Years 1849 and 1859 to Accompany a Report on the Forest Trees of North America
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We’ve just skipped a stone across the pond of Asa Gray’s life. Here are some links if you’d like to learn more.
Asa at 200 –https://huh.harvard.edu/book/asa-gray-200
The Asa Gray Bulletin – https://www.jstor.org/journal/asagraybull
Asa Gray: Faith and Evolution – https://sciencemeetsfaith.wordpress.com/2020/11/17/asa-gray-bridging-faith-and-evolution/
Asa Gray online papers – https://onlinebooks.library.upenn.edu/webbin/book/lookupname?key=Gray%2C%20Asa%2C%201810%2D1888
Asa Gray Award – https://www.aspt.net/asa-gray-award