Chemical-tag-based semi-annotated metabolomics facilitates gene identification and specialized metabolic pathway elucidation in wheat

The importance of metabolite modification and species-specific metabolic pathways has long been recognized. However, linking the chemical structure of metabolites to gene function in order to explore the genetic and biochemical basis of metabolism has not yet been reported in wheat (Triticum aestivum). Here, we profiled metabolic fragment enrichment in wheat leaves and consequently applied chemical-tag-based semi-annotated metabolomics in a genome-wide association study in accessions of wheat. The studies revealed that all 1,483 quantified metabolites have at least one known functional group whose modification is tailored in an enzyme-catalyzed manner and eventually allows efficient candidate gene mining. A Triticeae crop-specific flavonoid pathway and its underlying metabolic gene cluster were elucidated in further functional studies. Additionally, upon overexpressing the major effect gene of the cluster TraesCS2B01G460000 (TaOMT24), the pathway was reconstructed in rice (Oryza sativa), which lacks this pathway. The reported workflow represents an efficient and unbiased approach for gene mining using forward genetics in hexaploid wheat. The resultant candidate gene list contains vast molecular resources for decoding the genetic architecture of complex traits and identifying valuable breeding targets and will ultimately aid in achieving wheat crop improvement. Chemical-tag-based semi-annotated metabolomics combined with genome-wide association studies facilitates gene identification and specialized metabolic pathway elucidation in wheat.

Automated summary

This study investigated the relationship between metabolite modification and gene function in wheat. By profiling metabolic fragment enrichment in wheat leaves, the researchers identified 1,483 quantified metabolites that can be modified in an enzyme-catalyzed manner. Through genome-wide association studies, they were able to efficiently mine candidate genes associated with these metabolites. In further functional studies, a flavonoid pathway specific to Triticeae crops and its underlying metabolic gene cluster were elucidated. The researchers also reconstructed this pathway in rice using the major effect gene from the cluster. This study provides valuable insights into the genetic architecture of wheat and has implications for crop improvement.