Date of Award

2025

Degree Name

Biological Sciences

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Dr. Eugene Shakirov

Second Advisor

Dr. Kyle Palmquist

Third Advisor

Dr. Pamela Puppo

Abstract

Telomeres are conserved structures at the ends of eukaryotic chromosomes that promote genome stability. In most eukaryotes, the DNA found within these protective end caps consists of short, G-rich nucleotide repeats. Cells with critically short telomeres face a variety of potential adverse outcomes such as end-to-end chromosome fusion, apoptosis, etc. The length of telomeric DNA varies substantially between different plant species and even between genotypes of the same species. A previous study using T-DNA mutants of the model plant Arabidopsis thaliana with long or short telomeres suggested that telomere length may be an adaptive trait. Specifically, for reproductive fitness, the shortest telomere mutant outperformed all genotypes in control conditions, however, under high heat stress the longest telomere mutant experienced a significant increase in seed production compared to short telomere mutants. But there is still a large knowledge gap regarding how or if stress responses between naturally occurring genotypes within a population are impacted by telomere length status. The current study tested the hypothesis that natural telomere length variation can differentially impact Arabidopsis fitness depending on substrate quality (poor or control). Six A. thaliana genotypes with long or short telomeres were grown in control soil or in sand supplemented with ½ (moderate stress) or 1/10 Hoagland (more severe stress) solution. We then measured several plant life history traits and vegetative (biomass) and reproductive (total seeds produced) fitness parameters. As expected, plants responded to stress in a treatment-dependent manner, with significant decreases in chlorophyll leaf content, vegetative and reproductive fitness under moderate and more severe stress compared to control conditions. Our results revealed that telomere length influenced vegetative fitness and reproductive fitness parameters under control and stress treatments. Specifically, long telomere genotypes had higher vegetative fitness (biomass, number of inflorescence bolts) and total fruit production compared to short telomere genotypes. In contrast, short telomere genotypes produced a greater number of leaves, but only in control conditions, and higher number of seeds per fruit, on average, than the long telomere genotypes. These results suggest that telomere length can influence plant fitness responses and potential trade-offs for adapting life-history strategies to maximize survival and reproduction, specifically under substrate stress. Overall, our results may provide important insights into whether telomere length is a plant trait that can be manipulated to achieve higher crop yields in poor growth conditions.

Subject(s)

Biology.

Molecular biology.

Botany.

Arabidopsis thaliana.

Plant health.

Plants -- Effect of stress on.

Arabidopsis -- Molecular aspects.

Telomere.

Telomere -- Size.

Download

Share

COinS