Adaptive Strategies in Plant Physiology: Analyzing Duckweed (Lemna minor) Plasticity and Enhancing Potato Stress Resilience

Author

Megan J. Sichterman, University of Tennessee, KnoxvilleFollow

Date of Award

12-2023

Degree Type

Thesis

Degree Name

Master of Science

Major

Food Science

Major Professor

Scott C. Lenaghan

Committee Members

Alessandro Occhialini, John Munafo

Abstract

This thesis delves into the impact of stress on plants amid climate change, exploring strategies for mitigation. The initial focus is on duckweed stress tolerance, evaluating how different ecotypes respond to various stressors over three weeks. The L. minor ecotype from the subarctic climate, Norway, displayed the highest levels of tolerance and plasticity by having significantly larger growth areas compared to all other ecotypes across treatment groups after three weeks. Many samples underwent increases in growth after three weeks of stress exposure compared to just one week of stress exposure. Transcriptomic analysis showed that salt exposure caused repression of genes related to photosynthesis and plastid localization and organization in the first week, along with induction of stress response genes. The processes that were repressed in the first week were induced by the third week, causing growth areas to increase significantly. Copper sulfate exposure induced genes related to ion and metal transportation, as well as homeostasis, which contributed to the significant increase in growth seen in week three in these samples. This study offers that the 7-day ecotoxicity study that is currently used for Lemna minor may not cover the entire stress response. Additionally, as duckweed is used worldwide for many applications such as feed production or phytoremediation, the ecotype utilized may determine the success of the system.

Potato plants are also utilized globally, making stress mitigation strategies crucial as climates change. The following chapter discusses the increase of potato stress tolerance by means of Escherichia coli OtsB [trehaolose-6-phosphate phosphatase] gene insertion under the control of native flowering and tuberization promoters. The transgenic potato plants showed increased resilience to heat, photoperiod changes, herbivory, and competition as compared to the control wild type. The addition of excess trehalose to potato plants improved phenotypic stability in unfavorable environments and showed promise for more resilient agriculture. Overall, this exploration emphasizes the adaptability of plants to stress and the need for targeted interventions in suboptimal environments.

Recommended Citation

Sichterman, Megan J., "Adaptive Strategies in Plant Physiology: Analyzing Duckweed (Lemna minor) Plasticity and Enhancing Potato Stress Resilience. " Master's Thesis, University of Tennessee, 2023.
https://trace.tennessee.edu/utk_gradthes/10123