Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Genetics, Development and Cell Biology


Plant Biology

First Advisor

Philip W. Becraft


The general introduction including part of a book chapter (Chapter 1), a journal paper (Chapter 2), my side project (Chapter 3) and the general conclusions including part of a book chapter (Chapter 4) are included in this dissertation.

Chapter 2, in this chapter an analysis of NKD1 and NKD2 function in developing maize endosperm is described. We identify the DNA binding specificities of NKD1 and NKD2 and discern that NKD1 and NKD2 proteins can homo- and heterodimerize through their ID domains, and demonstrate they directly regulate transcription. RNA sequencing (RNAseq) analysis of nkd1 nkd2 versus wild type (WT) endosperm revealed that NKD1 and NKD2 regulate widespread processes, including nutrient reserve deposition, gene expression, as well as cell growth and proliferation. The characterization of the nutrient reserve phenotypes of nkd1 nkd2 mutants validated predictions of pathway analyses on transcriptomic data. My contributions included designing experiments, qRT-PCR and transgene florescent microscopy experiments, differentially expressed gene enrichment and pathway analyses, seed weight assays, kernel scanning electron microscopy, endosperm total nitrogen and protein content assays, principle component analyses (PCA), SAAB and MEME analyses, EMSA’s, NKD direct target and enrichment analyses, BiFC and Co-IP assays, transcription assays, starch branch chain length distribution, kernel starch content experiments and cloning all constructs used in the manuscript.

Chapter 3, in this chapter my side project involving a transcriptomic analysis of thk1 mutant endosperm and a thk1 suppressor/enhancer screen is presented.

Chapter 4, in this chapter a general conclusion of the results is discussed. A NKDs gene regulatory network of aleurone cell differentiation and maturation is proposed and a discussion of remaining research questions is presented.


Copyright Owner

Bryan Christopher Gontarek



File Format


File Size

148 pages