Title : Molecular genetics control of polyphenolic compounds synthesis in barley: Revealing the genes and their functions
Abstract:
Phenolic compounds are plant secondary metabolites with important functions in plant physiology. In barley, flavonoids belonging to this group are synthesized in grain envelopes and influence significantly the quality of barley grain and its application. For example, proanthocyanidins (also known as condensed tannins) are undesirable in malting cultivars as they cause chill haze reducing beer quality. In contrast, anthocyanins that can accumulate in aleurone layer and pericarp causing blue and purple color of grain, respectively, are promising functional food ingredients and are desirable in cultivars for human nutrition. To modify phenolic content of barley grain by marker-assisted breeding or genome editing approaches, knowledge of genetic control of its synthesis is necessary. In this study, the genes underlining synthesis of anthocyanins and proanthocyanidins in barley grain were identified and features of their functioning were established. Ant1, Ant2 and Ant25, Ant27 were identified as specific regulators of anthocyanins and proanthocyanidins synthesis, respectively, while Ant13 was shown to participate in regulation both pathways. It was shown that Ant1 and Ant2 encode transcription factors with the R2R3-MYB and bHLH regulatory domains, respectively, and their co-activation in barley grain determines anthocyanin synthesis there. Based on decreased transcription of the genes encoding enzymes of flavonoid biosynthesis in ant25 and ant27 mutants in comparison to the parental cultivars the regulatory functions for the Ant25 and Ant27 genes were suggested. The locus Ant13 was established to encode WD40-type regulatory factor, that activate expression of the flavonoid biosynthesis genes required for both anthocyanins and proanthocyanidins synthesis. The natural and induced allelic diversity of the genes was studied. The results obtained are of great fundamental importance, as well as contribute to breeding for the content of polyphenolic compounds in barley grain.
The study was supported by RSF grant ? 21-76-10024.
Audience Take Away:
- The data are of fundamental importance and may be interesting for plant geneticists;
- The target genes for metabolic engineering of barley varieties with desirable profiles of phenolic compounds in grain may be interesting for breeders;
- The data on allelic diversity of regulatory genes controlling synthesis of phenolic compounds in barley grain and their genetics stocks represent useful information for breeders
