What is it like to be a Plant Pathologist?

Some of you may know this, and some of you may not, but the homesteading business is not our main source of income. Jason, the founder of From Seed to Sprout, works full time as a plant pathologist, studying various fungal pathogens plaguing the southwestern United States. Let's take a dive into what a plant pathologist does and a typical day in the life of one from a first-person perspective.

My main goal as a plant pathologist is to study various fungal pathogens with a primary focus on the three most virulent ones affecting pepper plants primarily. The three pathogens I study are phytophthora blight (caused by Phytophthora capsici), rhizoctonia root rot (caused by Rhizoctonia solani), and verticillium wilt (caused by Verticillium dahliae). All three of these pathogens can cause wilt and overall death of the pepper plant - all with varying symptoms.

Phytophthora blight can cause stem death, leaf loss, wilting, and plant death.

Rhizoctonia hit the plant at the seedling stage, causing root rot which can kill the plant.

Verticillium can cause yellowing of leaves, wilt, and death.

So, what do I do in particular? I work closely with different chile pepper breeders to test different lines of chile for their resistance, tolerance, or susceptibility to these diseases. I get sent pepper varieties that have been cross-bred and, through various means, will test for their resistance in the greenhouse, laboratory, and field. Secondly, I research the use of biological extracts in their effectiveness of mitigating these diseases. Let's take a deeper dive shall we?

Let's start from the beginning and break down each component, from the lab, to the greenhouse, to the field. Starting with the lab. What I do in the lab is grow (culture) and maintain the pathogens in petri plates containing agarose (a gel-like sugar substrate conducive for fungal growth). There are a million different ways to test for resistance in the lab but I will keep it short and sweet and narrow it down to just a couple. One way I go about testing resistance is by planting the chile pepper seeds directly into the agarose plates, wait for them to germinate (sprout), then introduce the pathogen. I will then record symptoms of any stunted growth or morphological abnormalities. Another way to test is by utilizing a growth chamber, introducing the pathogen into the soil first, and then planting the seeds and recording any symptoms that may appear. As far as the biological extracts go, I make extracts of varying concentrations using different biological organisms and test them against the pathogens of interest. I also go about this in a few different ways. One way is by implementing what is known as a well study. This is where I remove some agarose from the petri plate, put some drops of my liquid extracts in the newly created holes, then add the pathogen and record its ability to grow. I will also do what is called seed priming, where I let the pepper seeds soak in the extracts I've created for a duration of time then plant them into sterilized sand, let them grow, then add the pathogen of interest. There are many other fungal-specific protocols I follow and experiments I set up, but I don't want to bore you or write a novel when this is simply a blog post. So I will spare you....for now. But maybe in the future.....?

Here is an example of a well study. As you can see, there have been three plugs of agarose removed, a spore solution of a beneficial fungus was added, and the pathogen was placed in the middle of the plate. As evident, provided by the picture above, the spore solution is mitigating the growth of the pathogen.

Spraying the controls with deionized water (above) and comparing them to the extract spray (below) for disease mitigation

*See caption on picture above

The greenhouse is my next area of study and experimentation. It's not as controlled as the lab but more controlled than the field. In the greenhouse, I take those same pathogens I grew in the lab, and I introduce them to our plants at various stages of their growth and development, depending upon the pathogen (rhizoctonia is a seedling disease while verticillium is a late-stage disease, etc.). I do this by either creating a spore solution then injecting the soil with said solution or by simply removing mycelial plugs from the agarose and placing them into the soil. After some time I will start recording any symptoms observed. But just because there is symptoms, how do I know it was that particular pathogen that caused it? To answer that question, I bring samples of the infected plants back to the laboratory and follow a process that allows us to pull the pathogen back out of the plant. For the extracts, I follow the same principles except, I will test my extracts on the plant by spraying the leaves before introducing the pathogen and compare the results to control plants that I just spray with sterilized deionized water.

The field testing is probably the easiest. It is similar to the greenhouse testing except I use an entire petri plate's worth of the pathogen of interest instead of isolating mycelial plugs. I will plant my pepper seeds from the breeder that supplied them to me, I will let them grow until they've reached the stage necessary for introduction to the pathogen, and I will then record the results. I have yet to test any of my extracts in the field and have only done resistance testing.

There are a multitude of varying experiments going on every single day in lab, the greenhouse, and the field. I also have the additional responsibility of managing the lab by keeping it stocked with supplies, training and educating undergraduate and graduate level students that work with me, and going out to talk to farmers, deliver products, and sample their fields, doing outreach, program management, and helping others set up their experiments as well. If we find a field that has any disease pressure, we will take infected plants back to the lab where we try to "recover" whatever pathogen is making them sick. We will then report to the farmers our findings and let them know the next steps necessary to ensure their success.

Outreach is a crucial component of my work as a scientist. I have gone to countless schools, employment fairs, and spring, summer, and fall camps to educate the next generations and give them a first-person perspective on life as a scientist.

This is a very interesting field of research and fairly new to me. I have a background in horticulture and plant science but not necessarily plant pathology, so I was very comfortable growing plants, but killing them on purpose was extremely difficult to do at first. Over the course of a little over four years working in this field, I can comfortably say that I'm used to it now. I am also very thankful for the opportunity to come full circle and learn about the pathogens that devastate the home garden, the landscape, and the farmers that grow our food. I'm also very thankful for the opportunity to be able to get out there and network and meet the growers and learn about the crops they grow and the problems they deal with in the field. It is good to know that I am doing my part to try and find ways to mitigate those struggles.

Created: 4/11/25