Identifying a Source of Beta‐Alanine and its Broader Implications in Arabidopsis thaliana by GC/MS

β‐alanine, a naturally occurring non‐protein amino acid, serves as a precursor for the formation of vitamin B5 and, ultimately, coenzyme A in plants. The synthesis of β‐alanine has not been explored extensively in plants despite interest in the development of alternative methods for producing natural compounds. Previous work in plants showed that β‐alanine could be synthesized from propionyl‐CoA. Our lab studies the degradation of branched‐chain amino acids (BCAAs) ‐ valine, leucine, and isoleucine ‐ in Arabidopsis thaliana and the degradation of valine and isoleucine are direct sources of propionyl‐CoA. Therefore, we proposed that valine and isoleucine could serve as a source of β‐alanine via the production of propionyl‐CoA. Using metabolic tracing with radiolabeled precursors measured by Gas Chromatography/Mass Spectrometry (GC/MS), we were able to measure β‐alanine via isoleucine but not valine. However, valine treatment of young seedlings did result in increased levels of β‐alanine, which suggested an indirect link through amino acid homeostasis. Additionally, we used a mutant seedline that lacks expression of an enzyme necessary for valine and propionyl‐CoA degradation ( mmsd‐1 ) to further emphasize the link between β‐alanine and propionyl‐CoA by shifting the equilibrium towards β‐alanine production. Here, we found that seeds had significantly high levels of β‐alanine compared to wild‐type seeds. Support or Funding Information This project was funded by the Jean Dreyfus Boissevain Lectureship for Undergraduate Institutions and Kenyon College.