Screening Zea mays (maize) lines for DNA sequence variations of interest to further understand Multiple Disease Resistance (MDR)

Maize is one of the most important staple and biofuel crops in the world (Schnable et al, 2009), feeding over 4.5 billion people (Research Program on Maize, 2016). In addition to feeding people, maize also feeds dairy cows. The brown midrib (Bm) market class of maize is preferred by dairy farmers because of low lignin levels, which allow the cows to digest their meals with ease. As a drawback, maize with lower levels of lignin are more susceptible to diseases, such as Northern Leaf Blight (NLB), caused by the pathogen Setosphareia turcica, and Fusarium Ear Rot (FER), caused by the pathogen Fusarium verticillioides. In fact, the diseased leaf area (DLA) exponentially increases in the Bm maize (Judith Kolkman). Past experiments in the Nelson Lab have shown that the phenylpropanoid (PP) pathway plays a critical role in lignification of Bm maize. My research investigates lignin levels in the Bm maize genes. I chose a series of Near Isogenic Lines (NILs) containing Bm genetic material of interest and grew them in the greenhouse. These NILs matched 97% of their DNA to the B73 maize genome. The 3% difference contained genetic variations known as introgressions. When the NILs in the greenhouse reached a height of 12-18 centimeters, their leaf tissue was sampled and extracted. Polymerase Chain Reaction (PCR) and agarose gel electrophoresis were employed in my studies to reveal the presence of introgressions at the loci, which was fundamental for understanding MDR. Understanding MDR has the potential to reduce maize yield losses and the amount of people succumbing to the effects of diseased food.

My Experience

When it came to the world of research, I wasn’t sure what to expect. As a first generation college student, it was hard enough learning the lingo required to pursue a bachelor’s degree. This internship introduced me to higher education in new and interesting ways. For the first time, I ran Polymerase Chain Reaction (PCR) experiments and extracted DNA. It was both frightening and exciting! Working under the tutelage of a mentor and collaborating with a fellow intern made the experience even better because we were all in the project together, which helped us foster a sense of teamwork. Being in the program was like doing a tiny tiny piece of a Ph.D and this offered me a firsthand glimpse into graduate school life. I’m glad I got the chance to study here. Essentially, I started to crack a code that had eluded me for so long.
Furthermore, I appreciated the opportunity to delve into social issues from a scientific perspective. As someone who avidly volunteers at organizations that mitigate homelessness and poverty, I approved of working on food insecurity with plant pathology and complex genetics. I saw a concrete example of the ways natural and social sciences go hand in hand.