Date of Award

8-2020

Degree Type

Thesis

Degree Name

Cell and Molecular Biology (M.S.)

Department

Cell and Molecular Biology

First Advisor

Dr. Sheila Blackman

Second Advisor

Dr. Matthew J. Christians

Third Advisor

Dr. Pei-Lan Tsou

Academic Year

2019/2020

Abstract

Like most seeds, Arabidopsis thaliana seed development is divided into three major phases: morphogenesis, storage deposition, and maturation drying. During maturation drying the seed becomes desiccation tolerant (DT) at some point and the seed rapidly loses water until its moisture level is approximately 10% on a fresh weight basis. The ability of the seeds to withstand this extreme water loss is hypothesized to be due, in part, to the accumulation of late embryogenesis abundant (LEA) proteins. In A. thaliana, there are 51 LEA proteins which are divided into seven groups based on amino acid sequence similarities. Group 1 LEA proteins consist of three members (6, 18, and 46), which exclusively accumulate during maturation drying. This paper focuses on LEA6 and investigates its involvement in DT in A. thaliana seeds. The rate and extent of germination of mutant (lacking the LEA6 gene product) and wild type (WT) seeds before and after artificial desiccation at varying developmental time-points were scored for 14 days and the germination results were analyzed using Kaplan-Meier Estimator. Fresh WT seeds had a higher final germination and a faster germination rate relative to mutant seeds, whether or not the seeds were desiccated. These results do not support an involvement of LEA6 in DT but rather suggest a role in germination.

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