**6. Utilizing modern technology to research the flavonoid pathway**

We currently have extraordinary knowledge about how different chemical components in plants are controlled in abundance, thanks to the recent rapid development of metabolomics and the use of varied populations for genetic mapping [42]. In a population of rice Zhenshan 97 and Minghui 63 recombinant inbred lines (RILs), metabolic QTL were discovered using high-throughput genotyping and metabolomics data, and some of the candidate genes for flavonoid content were further validated by looking at over-expression transgenic rice lines [43]. Flavonol 3-O-gentiobioside 7-O-rhamnoside (F3GG7R) synthesis in an Arabidopsis RIL population has recently been linked to a novel gene (BETA GLUCOSIDASE 6; BGLU6) [44, 45]. Following genome wide association studies (GWAS) on a diverse maize population that revealed the genetic effects underpinning metabolic heterogeneity, hundreds of loci related with metabolites from numerous pathways, including flavonoid metabolism, were found in maize [46]. The co-expression and direct target genes of the R2R3-MYB transcription factor P1 were also studied using near isogenic lines (NILs) carrying P1-rr and P1-ww. This discovery marked a significant advancement in our understanding of P1's gene regulation circuitry because targeted molecular tests showed that P1 regulates some well-known genes involved in flavonoid biosynthesis, such as FLS1 and A1 [47]. The corn earworm (*Helicoverpa zea*), which may cause significant damage to maize in the Americas, is naturally resistant to maysin (C-glycosyl flavone), which is contained in maize silks. Through QTL mapping [29] in 2004, two loci that can impart the salmon silks phenotypes salmon silks 1 (sm1) and salmon silks 2 (sm2) were found. Additionally, earlier genetic investigations suggested that P1 would be epistatic to the salmon silk mutation [13]. The molecular identification of the sm1 and sm2 gene products is revealed as an UDP-rhamnose synthase and a rhamnosyl transferase, respectively, based on the knowledge of the genes regulated by P1 and the existing sm1 and sm2 mapping information [48, 49]. The maysin biosynthetic pathway is therefore finished with the molecular characterization of sm1 and sm2.It can thus be anticipated that deep probing of further profiling studies will facilitate the elucidation of the

genetic complexity of maize flavonoid biosynthesis. Indeed, integrative approaches are increasingly applied to enhance our understanding of metabolic pathway structure and regulation and how these affect the end-phenotypes of plants [50].
