Plants can get rusty. No joke! There is a fungal pathogen called rust which can cover the leaves of plants. This is problematic given that leaves are the site where photosynthesis occurs, the process whereby plants use sunlight to synthesize foods from carbon dioxide and water in order to grow. While a plant may still be able to photosynthesize if the leaves contain just a little bit of rust, the more and more rust spreads across the leaves, the less and less surface area there is for photosynthesis to occur. When you get rust on a metallic item, there are several home remedies you can try to remove the rust, such as baking soda or a vinegar bath. But do plants have rust-removal options too? Possibly…and it’s what our guest this week, PhD student Maria-Jose Romero-Jimenez (or Majo), is trying to figure out.
Majo, who is in her second year of graduate school in the Department of Botany and Plant Pathology here at OSU, is using black cottonwood as her plant study species. Black cottonwood is a Pacific Northwest native which has many uses, including the paper industry in Oregon. Recently, the Department of Energy has also listed the black cottonwood as a plant of interest for its potential use as a biofuel. As you can imagine, with this much large-scale interest in black cottonwood, there is also huge interest in understanding how it is affected by disease and pathogens, and what can potentially be done to prevent pathogens, such as rust, from spreading.
Fortunately, it seems like black cottonwood has a natural ally that helps it fend off rust – yeast! Majo’s main research goal is to figure out what yeast colonies are able to prevent rust infestation of black cottonwood plants. While this task may sound relatively straightforward, it sure isn’t. Majo’s work involves both field and lab work and is started in the fall of 2020 when Majo had to isolate yeast colonies from a bunch of leaves that were collected in the PNW (primarily Washington and Oregon). This work resulted in isolating almost 400 yeast colonies, from which Majo had to select a subset to grow in the lab. Meanwhile, baby black cottonwood plants needed to be propagated, potted, and cared for to ensure that Majo would have enough grown plants for her first round of greenhouse experiments. These experiments involved a series of treatments with different combinations of yeast colonies that were applied to the black cottonwood plants before being sprayed with rust to see how plants in different yeast treatments would do.
Curious to know what the results of Majo’s first round of experiments was and what the next steps are? You can download the episode anywhere you get your podcasts! Also, check out Majo’s Instagram (@fungibrush) for some educational videos on how she conducts her research (as well as a lesson in Spanish!).