Date on Senior Honors Thesis
5-2024
Document Type
Senior Honors Thesis
Degree Name
B.S.
Department
Biology
Author's Keywords
Ustilago maydis; Sporisorium reilianum; Functional Homology; Mitochondrial Inheritance
Abstract
Ustilago maydis, a basidiomycete fungus, infects corn and displays dimorphism, transitioning between nonpathogenic and pathogenic stages. Its life cycle involves mating of haploids with different alleles, resulting in the formation of galls/tumors filled with teliospores. The a1 and a2 alleles regulate pheromone recognition and mating. The lga2 and rga2 genes in the a2 allele are crucial for uniparental mitochondrial inheritance. Sporisorium reilianum, a related fungus, has homologs of lga2 and rga2 with U. maydis. To test the functional homology of the S. reilianum genes, protoplasts of U. maydis strains deleted for lga2 or lga2 and rga2 were transformed using genetic constructs that bore the lga2 or both the lga2 and rga2 genes from S. reilianum, and transformants were confirmed through PCR analysis. In related experiments, teliospores produced from maize infections were analyzed via PCR to determine the mitotypes of these offspring from different combinations of parental mitotypes. Teliospore analysis revealed variation in mitochondrial DNA, suggesting recombination. The lga2 and rga2 genes play a critical role in mitochondrial inheritance in U. maydis and may also do so in S. reilianum. Teliospore analysis suggests the occurrence of recombination, indicating a possible difference in the role of rga2 in S. reilianum compared to U. maydis.
Recommended Citation
Thomas, Joshua, "Testing functional homology of the lga2 and rga2 genes of Sporisorium reilianum in Ustilago maydis" (2024). College of Arts & Sciences Senior Honors Theses. Paper 314.
Retrieved from https://ir.library.louisville.edu/honors/314
Lay Summary
This study investigates how Ustilago maydis, a fungus that infects corn plants, reproduces and causes disease. It has two life stages, one benign and one pathogenic, and mating between different cells is crucial for its reproduction, leading to growths filled with spores. Genes like a1 and a2 control mating, while lga2 and rga2 within a2 regulate mitochondrial inheritance. This study tested if similar genes in Sporisorium reilianum function similarly by modifying U. maydis to remove lga2 alone or both lga2 and rga2, then adding genes from S. reilianum. Spores from U. maydis infections to see if genetic material mixes, indicating recombination. This sheds light on fungal reproduction and disease in plants.
