Monthly Archives: May 2023

Fighting for your French fries

This week’s guest is Alexander Butcher, a second-year master’s student in the Department of Crop and Soil Science. Alexander has a wide variety of interests related to minimizing food waste and improving global food security, but his current research focuses on protecting potato crops from insect pests.

Typical chemical pesticides are effective deterrents against invading insects but can cause significant harm to the environment and to humans. Such substances can present health risks to the farm workers that apply the pesticides as well as the consumers who purchase and eat the treated crops. Runoff from agriculture can also cause damage to surrounding ecosystems. In light of these downsides, scientists are interested in finding safer alternatives to conventional pesticides. Alexander studies an alternative class of chemicals called elicitors, which act as signals to activate defense mechanisms of plants. Plants have evolved numerous chemical and structural defenses for fending off insect and microbial attackers as well as competing against other plant species. One such product of this evolutionary arms race is the caffeine that you might enjoy in your morning cup of coffee. Elicitors can selectively turn these defenses on or off. This gives farmers and plant breeders a lot more possibilities for using plant defenses to manage insects.

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The Colorado potato beetle

Alexander’s research focuses on potatoes, which are an important agricultural product in northeastern Oregon along the Washington border. One of the biggest insect pests of potato is the Colorado potato beetle. Alexander is testing strategies for using two synthetic chemical analogs of natural plant signal hormones– salicylic acid and jasmonic acid — to stimulate the natural defenses of potato plants. Jasmonic acid is a phytohormone that promotes defenses against insects that chew, like the Colorado potato beetle. Some of Alexander’s research shows that these defenses can lower the weight of beetles. He thinks that this is due to protease inhibitors, which disrupt the enzymes insects use to digest proteins. Similarly, salicylic acid plays a major signaling role in plant development and defenses against insects that pierce into the plant and suck out fluids, like aphids. While these natural products have the potential to serve as affordable and effective pesticides, their sublethal effects lag behind the efficacy of more lethal chemicals. To help close this gap, Alexander has been researching how potato defenses induced by elicitors can impact the behavior of the beetle and its ability to reproduce.

Alexander first came to an interest in agriculture through his passion for food. He was classically trained in French cuisine and worked as a chef for twelve years, where he experienced first-hand the amount of waste that happens in the food system. His travels in countries affected by food insecurity helped solidify a desire to return to school, and he attended Portland State for a degree in biology. Despite his day job defending crops from insect invaders, he maintains a significant interest in bugs, founding an entomology club at Oregon State. Alexander will be transitioning into the PhD degree in the fall and switching topics towards defending vineyards from vine mealybugs. He eventually hopes to pursue a career in academic research and education.

Alexander treating crops with elicitors

To hear more about Alexander’s story, including why he advocates for insects as a sustainable protein source, tune in this Sunday, May 28th, at 7PM on KBVR 88.7 FM.

Digging Deep: what on earth is there to learn from dirt?

There’s a big difference between human time and Earth–or soil–time. It’s what makes climate impacts so difficult to imagine, and climate solutions so challenging to fully realize. Take it from someone who knows: Adrian Gallo has spent the last decade studying the very idea of “permanence.”

It took an entire day to dig a 1x1x1 meter perfectly square soil pit in the HJ Andrews Experimental Forest outside of Eugene, Oregon. It’s a terribly cumbersome process, but you get much better data from this sampling method compared the conventional methods and the photos are better.

Adrian has dug through a lot of dirt. As a recent PhD graduate in soil science, his research focused on the carbon sequestration potentials of soil. Soil holds about twice as much carbon as our atmosphere. If you factor in permafrost (frozen soils in cold regions that are rapidly thawing) then soil holds nearly three times more carbon than both the atmosphere and all vegetation combined. And that’s a lot. 

Let’s back up a second for a quick carbon cycle overview: plants use CO2 to produce sugars through photosynthesis. Microbes eat these sugars, inhaling oxygen and respiring CO2, and when plants and soil decay, they release carbon dioxide back into the atmosphere. There’s a delicate balance between soil being a carbon sink (absorbing more carbon than it releases) or a carbon source (the opposite). More carbon dioxide in the atmosphere = more greenhouse gasses; more climate uncertainty.

Some of Adrian’s soil samples included sites in Alaska where the ground is permanently frozen year around, leading to pockets of frozen water, leading to the presence of an “ice wedge” seen here. In order to preserve the integrity (physical, chemical, and biological) of these unique soils, sampling and processing had to occur in a walk in freezer.

Soil’s a tricky thing to study. The age of carbon stored in soil ranges widely. Some plant-derived carbon enters the soil and cycles back into the atmosphere in a number of hours, but other soil carbon can remain underground for thousands of years. And around 12,000 years ago (right around the end of the last ice age) soils used to hold nearly 10% more organic carbon than they do now. Most of that carbon loss came along with the spread of industrial agriculture in the last 200 years. If we could regain some of that carbon storage capacity, we’d have a powerful natural climate solution.

Adrian examined soil cores from nearly 40 representative ecosystems across North America. Adrian’s research was unique in not only its depth (at below 30 cm they tested beyond most existing soil research) but also its length (part of a 30 year project).

The findings? First, soil can indeed be a natural climate solution, but only if farmers can be convinced to alter their land management practices in perpetuity. Many  land management practices to prevent carbon escape have been largely the same since the Dust Bowl (minimize tilling, plant natural windbreaks, cover crops, etc) but the expense has not made the switch financially worthwhile. To incentivize farmers, the emerging carbon market allows farm managers to get paid for the carbon they store by selling credits to large companies wanting to offset their emissions. It’s an interesting idea, but also plagued with problems. Big corporations are eager to market themselves as more climate friendly, which often leads to greenwashing. But more importantly, there’s a big question over how long this carbon needs to stay in the soil in order for it to count as a credit. It’s easier to motivate a farmer to alter their land management for 30 years–but that’s thinking in human time, not soil time, and that shortsightedness has some dire consequences, even if moving in the right direction. Now try convincing farmers to use these practices for 100 years–still not on the same scale as soil, but certainly getting closer, and an even tougher sell. 

Second, much to Adrian’s and the other researchers’ surprise, there seemed to be a homogenizing effect in endmembers of the soil. No matter what plant types grew aboveground, the distribution of plant-end-members was largely the same, from grasslands to mountain ranges. Adrian coined this term “ecosystem inertia” and it’s still not known why exactly this happens.  

After a decade of dirt, Adrian is pivoting away from academia and into the renewable energy sector. Tune in this Sunday May 21 at 7pm at 88.7 to hear more about his research and what exactly we can learn from dirt. Learn more about his work here.

Cheese and disease: how bacteria survive long term

This week we have Andrea Domen, a MS student in Food Science and Technology co-advised by Dr. Joy Waite-Cusic and Dr. Jovana Kovacevic, joining us to discuss her research investigating some mischievous pathogenic microbes. Much like an unwelcome dinner guest, food-bourne pathogens can stick around for far longer than you think. Andrea seeks to uncover the mechanisms that allow for Listeria monocytogenes, a ubiquitous pathogen found in dirt that loves cheese (who doesn’t?), to persist in dairy processing facilities.

Listeria hysteria

Way back in the early 2000s, there were two listeriosis outbreaks that were linked to cheese. Because of these two outbreaks, the British Columbia Centre for Disease Control conducted a sampling program over the course of a decade. From this program, 88 isolates of L. monocytogenes from five different facilities were recovered. Within this set of isolates, 63 were from one facility which is now (perhaps unsurprisingly) shut down. Those 63 microbes were essentially clones of each other, which means this one lineage of microbes seemed to carry something that allowed them to survive for multiple years. So how did that lineage of Listeria survive? Turns out, like a 1990’s Reebok, they pump it. Listeria uses a protein in its cell membrane called an efflux pump to remove harmful chemicals like sanitizers, antibiotics, and heavy metals from the cell. Essentially, when the cell absorbs something that is too spicy – it’ll yeet it back out. 

gif of an efflux pump

Don’t cry over contaminated milk

The idea that food borne pathogens are evolving to withstand processing environments is alarming, but fret not, the results of Andrea’s research are a first step to avoiding the creation of these super microbes in the first place. Instead, it can serve as a warning story for dairy production facilities about what can happen when L. monocytogenes contamination isn’t properly handled. In healthcare, it’s not uncommon to treat a microbial pathogen with multiple medications – as becoming resistant to several treatments is harder for the microbe than becoming resistant to just one. We are also able to apply this treatment method to sanitizing food production facilities by combining different sanitizers – but that is best left up to the chemists to avoid accidentally making an explosion or lethal gas. 

Andrea Domen

To hear more about how Listeria can survive better than Destiny’s Child be sure to listen live on Sunday, May 7th at 7PM on 88.7FM, or download the podcast.