Metabolomic Insights on Plant Growth-Promoting Yeast as Bioinput: Biochemical Interactions with Tomato Seedlings

Plant growth-promoting yeasts (PGPYs)-based bioinputs offer a sustainable approach in agriculture, increasing crop productivity and reducing environmental impacts. However, their chemical interactions with plants remain poorly understood. In this paper, metabolites and metabolic pathways were deeply investigated in tomato seedling leaves inoculated with active (L01AT) and inactive (L01IN) Sporidiobolus yeast. Yeast was applied near the roots of the tomato seedlings, and agronomic and metabolomic studies were performed after 40 days. A total of 73 metabolites, including primary and secondary, were annotated using mass spectrometry-based metabolomics. Inoculation of the yeast L01AT promotes more intense changes in the biosynthetic pathways of secondary metabolism compounds, such as phenylpropanoid biosynthesis, such as phenylpropanoid biosynthesis, flavone and flavonol biosynthesis, and anthocyanin biosynthesiss. On the other hand, inoculation of the yeast L01IN promotes changes in the primary metabolic pathways, such as lysine biosynthesis and porphyrin metabolism, which are compounds derived from yeast cell degradation after heating. This integrated agronomic, biological, and chemical analysis provides a comprehensive understanding of the metabolic reprogramming induced by Sporidiobolus inoculation in tomato seedlings. These findings contribute to the design of safer and more efficient bioinput strategies and support the discovery of bioactive compounds for advanced formulation development.