Date of Award

12-11-2025

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Agricultural and Environmental Sciences

First Advisor

Matthew Blair

Abstract

Cowpea (Vigna unguiculata L. Walp) is an annual legume of immense importance across the world. However, knowledge of its ability to tolerate aluminum (Al) at toxic levels is not as comprehensive. This stress is an issue globally and especially in the southeastern United States, which has many Al-toxic soils. Here we determined multiple cultivars both tolerant and susceptible to Al toxicity. This was expounded upon by employing RNA sequencing on two cultivars from the United States with significantly different tolerance levels to characterize genes and pathways associated with Al toxicity and response. Multiple well-established gene orthologs like STOP, STAR, and SAUR genes in addition to others like AUX1, PMEIs, and ABC-TRANSPORTERS from other species such as rice (Oryza sativa L.) and Arabidopsis (Arabidopsis thaliana L.) were implicated in this study both for response and tolerance to Al. Additionally, the genetic diversity of 192 cowpea genotypes from the United States was characterized using a high-throughput whole-genome sequencing (WGS) approach to characterize a panel of 192 cowpea genotypes from the United States. LD was found to decay The most appropriate number of ancestral populations for this panel was 9, and the mean inbreeding coefficient was 0.88. AMOVA determined that the majority of genetic variation is within individual genotypes. This shows that even the relatively narrow gene pool found in the United States can be well-characterized by WGS techniques, and that this panel can be utilized for future breeding or genetic studies.

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