Transgenerational Perpetuation of CHS Gene Expression and DNA Methylation Status Induced by Short Oligodeoxynucleotides in Flax (Linum usitatissimum).

Over two decades ago, short oligodeoxynucleotides (ODNs) were proven to be an effective and rapid technique for analysis of gene function without interference in the plant genome. Our previous research has shown the successful regulation of chalcone synthase (CHS) gene expression in flax by ODN technology. The CHS gene encodes a pivotal enzyme in flavonoid biosynthesis. The manipulation of its transcript level was the result of the specific methylation status developed after treatment with ODNs. In further analysis of the application of oligodeoxynucleotides in plants, we will focus on maintaining the methylation status induced originally by ODNs homologous to the regulatory regions of the CHS gene in flax. This article reports the latest investigation applied to stabilization and inheritance of the epigenetic marks induced by plants' treatment with ODNs. The methylation status was analyzed in the particular CCGG motifs located in the CHS gene sequence. Individual plants were able to maintain alterations induced by ODNs. In order to confirm the impact of methylation marks on the nucleosome rearrangement, chromatin accessibility assay was performed. The perpetuation of targeted plant modulation induced by ODNs exhibits strong potential for improving crops and intensified application for medicine, nutrition and industry.

Temporal biosynthesis of flavone constituents in flax growth stages.

Previous studies showed that chalcone synthase (chs) silencing in flax (Linum usitatisimum) induces a signal transduction cascade that leads to extensive modification of plant metabolism. Result presented in the current study, performed on field grown flax plants - (across the whole vegetation period) demonstrates that, in addition to its role in tannin and lignin biosynthesis, the chs gene also participates in the regulation of flavone biosynthesis during plant growth. Apigenin and luteolin glycosides constitute the flavones, the major group of flavonoids in flax. Alterations in their levels correlate with plant growth, peaking at the flower initiation stage. Suppression of chs gene expression causes significant changes in the ratio of flavone constituents at the early stage of flax growth. A significant correlation between flavonoid 3'-hydroxylase (F3'H) gene expression and accumulation of luteolin glycosides has been found, indicating that flavone biosynthesis during flax growth and development is regulated by temporal expression of this gene. The lack of such a correlation between the flavone synthase (FNS) gene and flavone accumulation in the course of plant growth suggests that the main route of flavone biosynthesis is mediated by eriodictyol. This is the first report indicating the ratio of flavone constituents as a potent marker of flax growth stages and temporal expression of F3'H, the key gene of their biosynthesis.