Thompson, Beth EPakulniewicz, Emma Louise2025-07-032025-07-032025-052025-05-02May 2025http://hdl.handle.net/10342/14206Reproduction in flowering plants is reliant on the correct function of the genes that regulate meristems, which are stem cell populations that give rise to specific tissues. Maize is a monoecious grass species that develops two inflorescences: the tassel, producing male flowers, and the ear, producing female flowers. In early development, tassel and ear primordia follow similar growth patterns that rely on shared regulators, but their meristems differentiate into their respective floral organs based on transcription factors (Thompson, 2014). Redundant genes zfl1 and zfl2 are upstream regulators of floral organ identity genes, and individuals with transposon insertion mutations in both zfls have defective floral meristems and severely altered phenotypes (Bomblies et al., 2003). However, these genes have only been studied in one inbred line (W22). Due to the highly diverse genetic background of maize, there is an abundance of family lines, each possessing a variable genetic makeup that manifests in a distinct presentation of mutations. The Thompson Lab has introgressed zfl1 and zfl2 mutations into the A619 background and has observed some enhanced phenotypic effects. We are characterizing the double mutant zfl1;zfl2 phenotype of maize with an A619 background by rearing individuals with varying numbers of mutated zfl alleles in a greenhouse, extracting DNA from their leaf tissues, identifying presence of zfl mutations through PCR and gel electrophoresis, and imaging early tassels and ears with scanning electron microscopy. In our investigation we have observed that zfl gene mutations have a dosage effect of severity, causing non-double mutants to exhibit mild floral defects. Evidence shows that zfl1;zfl2 double mutants demonstrate derepressed bracts, indeterminate floral meristems, and reduced tassel branching. These SEM micrographs have provided modern imagery of maize with zfl mutant defects and may aid in establishing the functions of zfl1 and zfl2, increasing understanding of maize development, and exploring the function of zfl homologs in other cereal crops.application/pdfDevelopmental biologyPlantHonors Thesis2025-06-12