MEET A WHITEHEAD POSTDOC: Rebecca Povilus

Postdoc Rebecca Povilus

Rebecca "Becky" Povilus is a postdoc in Whitehead Institute Member Mary Gehring’s lab investigating the evolution of reproduction in plants. We sat down with Povilus to learn more about her and her experiences in and out of the lab.

 

What are you investigating?

Most broadly, I'm interested in the evolution of reproduction in plants. Narrowing down, I like thinking about endosperm, which is this super cool tissue that is unique to flowering plants. With flowering plant reproduction, each pollen grain has two sperm in it. The two sperm get delivered to the ovule, which contains two female gametes, and each one is fertilized by one of the sperm. One of these fertilization events produces the embryo and the other produces the endosperm. So the endosperm is a sibling tissue to the embryo, and it is involved in regulating nutrition investment into the seed and ultimately the embryo. One of the reasons I'm interested in the endosperm is because it plays such an important role in our lives. Most of the calories that we eat are actually from endosperm tissue. Pretty much all cereal crops, like corn, wheat, rice, and barley; these crops have been selected over time for nutrition that’s stored in the endosperm. I think it's fascinating that what you're eating most of the time is this weird sibling tissue that you may not have even heard of.

Endosperm's also really interesting in the sense of thinking about how novel developmental programs and novel tissue types evolve. Endosperm is one of the defining characteristics of flowering plants, but we know so little about how it evolved. It’s been suggested that endosperm could be thought of as a modified embryo or as an extension of female gamete development that gets triggered by fertilization. Either way, where did its developmental programs come from? Why does this second fertilization product not develop as a second embryo? I am building on my PhD work, which focused on how the endosperm plays into seed development in an early diverging lineage of flowering plants: the water lilies. Studying early branching lineages like water lilies is important for trying to figure out the early evolution of flowering plants, and can help explain patterns of diversity that we see across the whole group. As part of Mary’s lab, I’m still working with water lilies, but I’m now focusing on how imprinting (parent-of-origin effects on gene expression) may have evolved as an important component of endosperm development. As part of this, I’m thinking about how the processes that regulate genetic imprinting and/or are regulated by genetic imprinting have evolved in flowering plants.

 

What did you want to be as a kid?

I vaguely recall wanting to be a veterinarian at some point, and then my dad had me watch a documentary about being a livestock veterinarian. There was surgery on a horse, and my reaction was “no thank you!” Later, my dream job was to make those dioramas you see at natural history museums. Honestly, designing and making those is probably still a dream job for me.

 

What drew you to the field you’re in now?

I've always been really interested in biodiversity. I thank David Attenborough in part for that, and Nature and NOVA, those kinds of documentaries. Then in undergrad I took as many organismal diversity classes as I could: things like insect diversity, and vertebrate or invertebrate paleontology. When I took my first plant systematics course, I got super excited because it was this whole other world of organisms that you don't really think about—at least that I had never thought about that much — even though you see them every day. It was really interesting to learn about how plants build themselves as they grow. It's so different than how animals develop, and it’s really fun to think about these different types of developmental processes result in different types of organisms. But in any case, I got hooked on plants after I took my first plant class in undergrad.

 

What's your favorite part of your job?

I love microscopy, I’m so happy when I get a chance to get some microscope time in. One thing about working with seeds is they don't look like much from the outside, but there's a lot going on inside of them. You’re not going to see that unless you make a microscope slide or do whole seed imaging. This might sound dorky, but even though I've looked at probably thousands of seeds at this point, every time I look at a new seed under the microscope it's like opening up a little present.

 

What do you see when you look inside of a seed?

It depends on if you're looking at a seed while it's still in the early stages of development or a mature seed. The inside of a seed is continually changing. There are three entities interacting: you have the embryo, which is the thing that's going to germinate and become the next plant. That's covered in a seed coat, which is actually left-over tissue from the mom, and in between the seed coat and the embryo is the endosperm, which is the product of a second fertilization event. It's so interesting to see how these three different entities change throughout development; each has its own developmental trajectory but they all have to work together to produce a healthy, functional seed.

 

What is it like working in the Gehring lab?

I really like the dynamic with all of the different people that we have in the lab right now. Everyone is generous with their time, in terms of sharing expertise or being there to offer support in pretty much any capacity. During my undergrad I decided to focus on plant biology, and my PhD was in a one hundred percent plant biology lab. But in Mary's lab, everyone has very different backgrounds. There's a joke in the lab that people here are either molecular biologists who happen to work on plants or plant people who happen to do molecular biology, and I'm definitely the latter. It's nice to have so many perspectives all in one place.

 

What’s the biggest disaster you’ve ever had in the lab?

I was doing a procedure called an in situ hybridization, and with the particular types of samples I was working on, this was maybe a four day protocol. During the run of this protocol, I had changed to using a new type of sample holder for some of the last steps. What I hadn't realized was that the plastic they were made of would be dissolved by one of the solutions I was using. So near the end of the procedure, I put in this solution, and I immediately see the plastic wells dissolving. There was some weird interaction with the sample, and basically, after four days of work I watched my samples become encased by plastic goop and get completely ruined. I thought: I'm going to clean this up, and then I'm going to go get myself a candy bar and just sit for a little while. 

 

What's the most surprising thing you've seen in the lab?

Well, it was not a pleasant surprise. In my PhD, I was growing water lilies in tanks. Originally, I'd started working with a species of water lily that we collected from ponds around Boston and brought into the lab, so it wasn’t unusual to see bugs or other little critters in these tanks. One day I realized we had leeches. We were cleaning out the soil, and my first thought was "What's this leech-like thing?” and then, “Oh it's actually a leech." We thought since there were no animals in the tank that the leeches would die off, but they hung around for maybe a year. When we switched from working with one type of water lily to another type, we had to clean out the tanks. By the time we did that, I was pretty sure the leeches were gone, but we still bleached the tanks very well when we had the chance.

 

What are your hobbies outside of work?

I enjoy cooking quite a bit. I think I’ve developed that as a hobby out of practicality; you have to eat, so you might as well eat something that you take pride in and that is delicious, hopefully, and reasonably healthy. A couple of months ago I splurged on a big order of dried chili peppers, so I've been experimenting with different combinations to make mole sauces and salsas. I also garden – as if I don’t grow enough plants at work! I had a community gardening plot a couple of years ago that was twenty by twenty feet. It's surprising how much food you can get out of that. I was bringing in bags of lettuce and veggies multiple times a week for co-workers. Right now, I just have some planters outside my door, but I’ve got a small tomato jungle growing there.

Also, I have done ceramics on and off since high school. However, since moving to Boston it's been a little hard to find an affordable studio, especially one somewhere that I can get to multiple times a week. So I haven't done ceramics in a while, but I would love to do that again.

 

Do you collect anything?

In undergrad, besides doing a lot of organismal diversity courses, I also took a lot of geology classes. I went on quite a few geology collecting trips. In southern Michigan there's not much geology beyond glacial till, so we'd have to do road trips to different states. I think the farthest one was to New Mexico. I still have a couple shoeboxes and a windowsill full of rocks and fossils that I've collected over the years.

 

Where do you see yourself in ten years?

Hopefully still doing research — but I wouldn't say no to the museum diorama job. 

Whitehead Institute postdoctoral researcher Rebecca Povilus

Image: Conor Gearin/Whitehead Institute

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