Abstract
BackgroundFlavonoids constitute a diverse class of secondary metabolites which exhibit potent bioactivities for human health and have been indicated to play an important role in plant development and defense. However, accumulation and variation of flavonoid content in diverse maize lines and the genes responsible for their biosynthesis in this important crop remain largely unknown. In this study, we combine genetic mapping, metabolite profiling and gene regulatory network analysis to further enhance understanding of the maize flavonoid pathway.ResultsWe repeatedly detected 25 QTL corresponding to 23 distinct flavonoids across different environments or populations. In addition, a total of 39 genes were revealed both by an expression based network analysis and genetic mapping. Finally, the function of three candidate genes, including two UDP-glycosyltransferases (UGT) and an oxygenase which belongs to the flavone synthase super family, was revealed via preliminary molecular functional characterization.ConclusionWe explored the genetic influences on the flavonoid biosynthesis based on integrating the genomic, transcriptomic and metabolomic information which provided a rich source of potential candidate genes. The integrated genomics based genetic mapping strategy is highly efficient for defining the complexity of functional genetic variants and their respective regulatory networks as well as in helping to select candidate genes and allelic variance before embarking on laborious transgenic validations.
Highlights
Flavonoids constitute a diverse class of secondary metabolites which exhibit potent bioactivities for human health and have been indicated to play an important role in plant development and defense
Variation of flavonoids in different maize populations An association mapping panel (AMP) and two recombinant inbred line (RIL) populations were planted in multiple environments and the mature kernels harvested from these six field experiments were used for LC-MS/MS based metabolite profiling
In our previous metabolome-based genome wide association studies (GWAS) study, 983 metabolite features were identified in the AMP [44]. 184 of these 983 metabolite features with chemical or putative annotations were analyzed in BB and ZY RIL populations subsequently [47]
Summary
Flavonoids constitute a diverse class of secondary metabolites which exhibit potent bioactivities for human health and have been indicated to play an important role in plant development and defense. Accumulation and variation of flavonoid content in diverse maize lines and the genes responsible for their biosynthesis in this important crop remain largely unknown. Increasing yield while providing added nutritional value in maize is imperative to meet the growing nutritional demand of the huge global population [3, 4]. Understanding flavonoid biosynthesis in maize and the genetic basis underlying natural variation of the contents of members of this compound class is essential for maize enhancement in terms both of improving its nutritional value and in maintaining yields by ensuring stress tolerance
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