Ever since I was an undergraduate researcher, I've been enthralled with the genome of C. sativa. This ancient oilseed and newfound aviation biofuel crop, is an allohexaploid containing the genomes of three different parental species. It was long puzzling to me the identity of these parental species - where did they come from? Do they still exist in the wild? How did they hybridize and undergo polyploidization to produce a robust crop capable of colonizing new niches and dominating as a weed of flax? These were the principal questions I had in the back of my mind as I continued my research in the genus during graduate school. Preliminary data consistently showed that C. hispida was one likely parent of C. sativa, but for so long the others were elusive. It wasn't until last year with the description of a new diploid Camelina species, C. neglecta, that the tables were turned. Research from several groups had identified an accession of C. microcarpa held in the United States Department of Agriculture's seed bank, as being a truly unique and bizarre specimen. In fact, this accession was not C. microcarpa at all, despite many morphological similarities, it turned out to be the distinct species C. neglecta, and as of now has only found in Southern France. Due to its recent discovery, very little is known about C. neglecta and why it isn't present in regions of high Camelina species diversity (i.e. The Caucasus). However, we now know that this formerly elusive entity was the missing link in the story of Camelina.
With the immense support of my collaborators at the Central European Institute of Technology (CEITEC) in the Czech Republic, we have finally solved the mystery of C. sativa's origins. Two diploid cytotypes of C. neglecta hybridized and underwent whole genome duplication to form a tetraploid comprising these two C. neglecta genomes. Next a C. hispida diploid joined the mix and subsequently hybridized with this tetraploid resulting in an allohexaploid Camelina species known as C. microcarpa. About 5,000 to 10,000 years ago C. microcarpa became the target of selection for agricultural traits starting the process of domestication that ultimately resulted in the oilseed crop C. sativa. In addition to these insights, cutting edge cytogenetics was used to infer the ancestral Camelina genome structure which gave rise to all Camelina species. Interestingly, this study also uncovered evidence of complex chromosomal rearrangements, a phenomena associated with many human genetic diseases.
Congratulations to Teri, Milan, Ihsan, and Martin for all of the hard work and the fantastic new publication in The Plant Cell: http://www.plantcell.org/content/early/2019/08/28/tpc.19.00366
Congratulations to the Kutchan lab on a fantastic new study published in Nature Sustainability entitled "Enzyme morphinan N-demethylase for more sustainable opiate processing". This research involved the screening of an opium processing waste pond to identify micro-organisms capable of metabolizing opiates. Poppy (Papaver spp.) plants produce many natural opiates, including some used in medicine such as thebaine and morphine. Thebaine is an opiate alkaloid used in the production of many types of opiates as well as drugs used in cases of opiate overdose such as naloxone. In this study, waste pond sludge was screened on a minimal media of thebaine as the only source of carbon. A Methylobacterium sp. was identified which could metabolize thebaine through N-demethylation, an important and currently costly step in the synthesis of drugs for the treatment of opiate addiction. Further analyses lead to the discovery of the enzyme morphinan N-demethylase (MND), which is responsible for the ability of this microbe to metabolize thebaine. This reaction removes the N-methyl group from thebaine and in turn provides a carbon energy source to the Methylobacterium. Furthermore, the enzyme was demonstrated to withstand a variety of temperatures, pH levels, and solvents, indicating its potential to be used for green chemistry reactions in industrial settings. The potential of MND for biocatalysis of opiate addiction treatments may provide a more sustainable production of these high-in-demand drugs, bypassing steps in pharmaceutical synthesis which currently utilize toxic substrates at relatively low efficiency.
This work made it on the cover page of Nature Sustainability's June 2019 issue. I'm honored to have contributed to this amazing work. Find our paper at: https://www.nature.com/articles/s41893-019-0302-6
Image credit: Dr. Howard Berg
One of the many exciting experiments I've been working on has reached a milestone. We have just completed a drought experiment on the LemnaTec automatic plant phenotyper. This instrument includes a massive grow room, automatic watering, daily plant scans and weight measurements. Approximately 1,100 Camelina were grown under five watering conditions to address questions regarding Camelina's ability to withstand (and in some cases, thrive) in drought conditions. Surprisingly, we recorded no mortality, even under the most extreme drought conditions we tested.
When the experiment started, these seedlings were just emerging, and within a few weeks the growth chamber burst into a sea of green. By the end of the experiment many had already began to flower.
These Camelina were then transferred to a greenhouse to live out the rest of their lives. Soon these will set seed, and we will examine the impact of drought on seed yield and oil quality. Each watering treatment will be continued throughout the span of the experiment with fine-tuned irrigation systems. Thanks to all of the hard work of the employees at the Danforth Center for setting up this irrigation system for our project!
I'm excited to say that years of work has finally culminated in the description of a new species of Camelina, C. neglecta, which may be a relatively common taxa in Europe. Because this species shares many morphological features with C. microcarpa and C. rumelica, its genomic distinctness was overlooked for hundreds of years. The type specimen was collected in Causse Méjean, Southern France in 1996. This area is a limestone plateau with Mediterranean-like climate. The area boasts many steppe flora, and resembles the environments in which other wild species of Camelina are known to occur in Europe, Turkey, and the Caucasus. Although this is a unique geographical area in France, we believe that C. neglecta likely occurs throughout Southern Europe. Infrequent evidence of 2n = 12 chromosome counts obtained across Europe for C. microcarpa, are almost certainly belonging to this taxon. My next step will be to conduct field expeditions across Southern Europe to obtain novel populations of C. neglecta for further research.
Camelina neglecta inflorescence and developing fruits.
Camelina microcarpa infloresence and developing fruits. Here the petals remain open and visible for some time before withering post-anthesis.
Camelina rumelica infloresence, with relatively larger, showy petals, which fade to a creamy white.
The key morphological characters of C. neglecta include reduced petal size, simple and forked trichomes on stems (pilose/crisped), and an increased ovule number (i.e. more seeds per fruit). Seeds of this taxon were found to be mucilaginous when wetted. Most importantly, this new species has a unique chromosome count (2n = 12) and genome size, indicating it is a diploid species (whereas C. rumelica and C. microcarpa are tetraploid and hexaploid, respectively).
On a trip to France in Fall 2018, I visited the herbarium at Bordeaux (BORD) to view the original specimen, and to my surprise the specimen never existed. Instead, only seeds from this elusive species were collected in Causse Méjean, and deposited in the herbarium's Index Seminum (seed bank). These seeds were given to the United States Department of Agriculture's National Plant Germplasm System, which provides researchers world-wide access to plant germplasm. This crucial work at the BORD herbarium wouldn't have been possible without the enthusiasm and support of my brother, and great friend Chris. Thanks for all the shenanigans!
Read the publication for more details at: phytokeys.pensoft.net/article/31704/
I spent all of last week working at the USDA's Northern Regional Laboratory in Peoria, Illinois collecting oil phenotype data for a panel of Camelina sativa cultivars. This exciting collaboration is looking at oil composition and drought tolerance and their genetic underpinnings. One of my roles in the project has been to use Near-infrared Spectroscopy (NIR) to quickly obtain measurements of seed oil content and quality, nitrogen, moisture, and glucosinolate content. The findings from this work will facilitate that adoption of Camelina cultivars best suited to regional climates and which have optimal yield and oil quality. More to come soon!
Most of my work studying the genus Camelina has utilized specimens I collected in their native range of Turkey and the Caucasus. I have largely ignored those cosmopolitan Camelina species which occur commonly throughout the United States, mainly because of the assumption that they harbor little genetic diversity as a result of their recent introduction. However, I have started a new study to understand how plants adapt (and respond plastically) to different climatic regimes. One major component of climatic adaptation in seed plants is thought to be differences in seed oil composition which regulates the seed's ability to utilize the energy stored as fats at different temperatures.
The purpose of this collection trip was predominately to collect plants across as wide of a latitudinal gradient as possible to make comparisons between climate and seed fatty acid composition. The Eastern edge of the Rocky Mountains provides an excellent habitat for Camelina and spans a large latitudinal range, and thus the focus of these collections. Along with my undergraduate research assistant (Amy Lee), I embarked on a ten day journey in search of Camelina. We traveled across seven U.S. states, drove over 5,000 miles, and collected Camelina from over 50 unique localities spanning 12 degrees of latitude.
We started our collections at the lower latitudes working our way up. Our first destination was New Mexico:
From New Mexico we worked our way up through Southern Colorado along the eastern edge of the Rocky Mountains and its foothills.
From Colorado we drove all the way through Wyoming and Montana, going as far north as the Canadian border before heading back.
And of course, no expedition is complete without a little bit of sight-seeing!
Stay tuned for more about our findings from this study!
I'm thrilled to announce the publication of my first-author publication in the journal Molecular Phylogenetics and Evolution on the evolution and phylogenetics of the genus Camelina. One of the main findings of this work is that C. sativa was likely domesticated from the wild and world-wide weed, C. microcarpa. This finding provides further evidence that C. microcarpa may be utilized for it's valuable genetic diversity. For instance, "wild" traits may be introgressed into the crop allowing to enhanced traits such as drought and salt tolerance, increased yield, pest and disease resistance and etc.
Read the article here!
Last week I took a quick trip to Washington D.C. to visit the National Geographic HQ and the United State's herbarium at the Smithsonian Institute.
While visiting National Geographic I was able to touch base with my program officer for my 2017 travel grant and discuss some of the results and challenges of my most recent collection trip. On top of that, I ate some surprisingly delicious cafeteria food, and visited the current exhibits at the National Geographic museum. Thanks Jill!
Having always heard about the Smithsonian Natural History museum, I couldn't miss the opportunity to visit, and to examine one of the largest collections of plant specimens in the United States. Not surprisingly, most of the Camelina specimens deposited here originate from the United States, where Camelina diversity is low. Nevertheless, the experience was worthwhile. As I am coming to find, the more Camelina specimens I examine, the more sense I can make of the evolution, domestication, and spreading of this fascinating crop.
My downtime was spent exploring the United States Botanical Garden. On a surprisingly small parcel of land adjacent to the U.S. Captiol building, this botanical garden sports a great variety of plants in many greenhouses. As with all (?) museums on the mall, the garden is free for all visitors and definitely worth passing through.
With Ivan Ivanovich driving, we departed Uman for his home in Kherson. Ivan, an expert of flora in the Kherson region and beyond, was an excellent guide and skilled driver for the occasionally treacherous roads of the region.
On the way to Kherson we stopped at a mine quarry turned recreational area, and after a quick dip in the water, we were back on the road and looking for more Camelina localities on the way to Kherson. Luckily, as we drove further south, Camelina became more and more common.
Three days were spent in the fields around the Kherson region (and surrounding oblasts). The first day we traveled to Odessa stopping at many dozens of localities on the way, and the second day we traveled east through the Kherson oblast all the way to Melitopol’ before turning around. Finally, on my last day of collecting, we traveled along a road following the eastern side of the Dniper river north east of Kherson.
Camelina was extremely common in these areas, in part due to the favorable dry and warm climate that most species of Camelina are adapted to. In fact, some areas were too dry and warm even for Camelina, for instance the Olesky Sands, a small desert in the Kherson oblast.
From Kherson, I traveled by bus back to Kiev to wrap up my work at the M.G. Kholodny institute of botany. I gave my farewells and thanked Dr. Sergei Mosyakin for all his excellent support and assistance with organizing field work for this project, and his ability to connect me with botanists and field experts throughout the country.
I arrived in Uman to work with some local collaborators and field experts in the region. During the extent of my time spent in Uman, I stayed at the hotel on the campus of the Sofiyivka Dendrological park. One can spend hours walking around the labyrinth of paths and trails and still not come close to seeing the whole park. Originally started over two hundred years ago in what was then Poland, the park has been constantly expanding. The many ponds, lakes, and streams provide for a tranquil atmosphere and beautiful scenes, as well as welcome sights for sore feet.
Three days of field collections took me all around the general vicinity of Uman, and fortunately Camelina was more commonly found than in the Western parts of Ukraine. Mostly we drove on very rural (and bumpy) roads in small loops covering ground in every direction around Uman.
Uman lies near the border of the "Forest Steppe" vegetation zone that covers most of central Ukraine, and is quite close to the dry steppe that occurs in the southern regions.