Growing plants and minds: Examining soft rot causing bacteria and students' understanding of genetic concepts

Abstract

Soft rot diseases cause crop losses all over the world. These losses can have large economic impacts and threaten international food security. Soft rot bacterial pathogens produce pectolytic enzymes that attack the pectin around plant cells resulting in smelly, wet, and mushy tissue maceration. Once symptoms are visible, the crop cannot be used or consumed in any way. A wide range of vegetables, fruits, and ornamental flowers can be affected by soft rot disease. The plant themselves have defense strategies to protect against invaders, but plant pathogens have their own strategies to evade the host immune system. The most common soft rot agents are Pectobacterium and Dickeya species. Recently, another plant pathogen, Erwinia persicina, has been described as a soft rot agent, but a detailed analysis of this pathogen has not been conducted. Here, we provide the first genomic analysis of Erwinia persicina and the first investigation into the biological role of a phenolic acid decarboxylase gene found in Erwinia persicina. Erwinia persicina shares traits with both common soft rot agents and other Erwinia species, while having unique characteristics of its own. The putative phenolic acid decarboxylase gene confers the ability to utilize phenolic acids, including caffeic acid and p-coumaric acid, when cloned into Escherichia coli LMG194 cells. The phenolic acid decarboxylase has the potential to be a novel pathogenicity factor for soft rot pathogens. Future researchers could leverage these results into in-field diagnostic tools, targets for novel control measures. While it is important to understand how plant pathogens persist in the plant environment, interact with their plant hosts, and cause disease, it is also important, as researchers and instructors, to understand how students learn scientific concepts to effectively teach future scientists and an informed public. Science education research aims to investigate all factors that contribute or impact student learning including student attitudes and motivations, the classroom environment, or the type of instruction received. When comparing different learning strategies, it is important to be able to accurately measure student learning of specific concepts. Concept inventories are multiple-choice assessments that are rigorously tested to evaluate student understanding and pinpoint student misconceptions. We provide an examination into classroom environment, specifically, how seat position can impact student performance, as well as, the development of the Mutations Criterion Reference Assessment (MuCRA) and an investigation into the misconceptions students hold about mutations. Students that sit in the back of a large introductory biology course performed worse and attended less. When accounting for the lowered attendance in a mediation model, the negative effects of sitting the back were more associated with attendance than seat position. The MuCRA was found to be a valid and reliable instrument that contained distractor options that correctly pinpointed common misconceptions. Student misconceptions about mutations persisted across years in college (1st-4th year), but did not persist across levels of biology experience (introductory to advanced). More interaction with biology concepts changes how students select their responses on the assessment. This research has implications for evaluating teaching strategies, providing instructor resources to measure student learning and misconceptions, and insight into how the classroom environment can impact student performance.