Abstract

Maize anther development is an ideal model for studying plant cell differentiation and development. Within a fully differentiated pre-meiotic maize anther, four somatic cell layers surround a central meiocyte population and each of these specialized cell types, including the germinal cells, develop from the somatic floral meristem. The tapetal cell layer is the innermost somatic cell layer and progresses through a series of cell state changes to support the developing meiocytes. The organization of a maize anther provides many opportunities to investigate cell fate acquisition, cell state transitions, and cell non-autonomous signaling regulating development. Transcription factors are key regulators of gene expression, directing transcription initiation, and as such they play a crucial role in cell differentiation and development. A family of basic helix-loop-helix (bHLH) transcription factors, Male Sterile (MS) 23, MS32, bHLH122, and bHLH51, regulate tapetal cell development. Here, we develop an epitope tagged allele of bHLH122 and leverage this line to define the protein-protein interactions of bHLH122 across anther development. We demonstrate that bHLH122 interacts with different binding partners across two stages of tapetal cell development. The line we developed is a new tapetal-specific marker line, identifying the tapetum in meiotic and post-meiotic anthers. We test the contribution of the major protein domains of bHLH122, the bHLH and ACT (aspartate kinase, chroismate mutase and TyrA)-like domains, for their individual and combinatorial effect on binding partner selectivity. We propose that the ACT-like domain of bHLH122, MS23, and MS32 facilitate the formation of a novel bHLH tetrameric complex. We also develop new methods to study transcription factor combinations, leveraging single cell sequencing, expansion microscopy, and anther protoplasts.

Committee Chair

Blake Meyers

Committee Members

Elizabeth Kellogg; Hani Zaher; Virginia Walbot; Xuehua Zhong

Degree

Doctor of Philosophy (PhD)

Author's Department

Biology & Biomedical Sciences (Plant & Microbial Biosciences)

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

4-28-2026

Language

English (en)

Download

Available for download on Tuesday, April 27, 2027

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