Annotation of Gene-metabolite Functional Relationships Using Multi-omics Mapping of the Sorghum Bioenergy Association Panel

Abstract Description:

Plants synthesize a multitude of diverse metabolites crucial for plant survival and adaptation with implications in various biological processes and applications in agriculture and human health. However, the identity of most plant metabolites and the genes involved in their synthesis and regulation remain unknown. Thus, improving our understanding of plant gene-metabolite functional relationships is needed to unlock higher plant productivity and stress tolerance. We used a multi-omics approach combining untargeted liquid chromatography-mass spectrometry (LC-MS), LC-UV absorbance, precursor isotope labeling, and genome-wide association (GWA) to identify and characterize mass features and the alleles in genes responsible with their variation in the Sorghum Bioenergy Association Panel (BAP). Several compounds were identified including multiple flavonoids and dhurrin. These compounds were aligned to isotopically labeled aromatic amino acids to determine precursor of origin using PODIUM. Functional validation of both compound identities and gene functions were further explored via reverse genetics studies using a sequence-indexed EMS mutant population sorghum. The same untargeted LC-MS approach was used to profile a set of EMS mutants. One such mutant had a high-impact point mutation in CHALCONE SYNTHASE an important enzyme in flavonoid biosynthesis allowing the identification of a suite of flavonoids. Cross validation between the EMS mutant population and association mapping allows efficient validation, or rejection, of candidate genes identified by association mapping. Comparisons between LC-MS and LC-UV association data also help validate and identify mass features of interest. Additionally, total absorbance at specific wavelengths or the ratio of two specific wavelengths were mapped to identify alleles in genes associated with absorbance variations and higher abundances of light-absorbing compounds. LC-UV total absorbance association mapping can be compared and applied to field hyperspectral data, thus providing another application for the wealth of hyperspectral data collected from field studies.

Equity and Inclusion: This proposal showcases the work of researchers from a wide range of cultural, ethnic, and academic backgrounds, each bringing unique expertise to the table. A key aspect of this project is the mentorship and support of early-career researchers, including myself, other graduate students, postdocs, and undergraduate students. This project involves the analysis of large-scale, complex datasets. During my talk, I will ensure an inclusive environment by clearly explaining the results in an accessible manner for all participants. I will also encourage questions and discussions to foster engagement and understanding among attendees.