Abstract
In Arabidopsis, flavonoid biosynthesis is regulated by MYB transcription factors such as MYB75/PAP1 for anthocyanin and MYB12 for flavonol. We have generated the transgenic lines over-expressing both PAP1 and MYB12 (WOX1-1,2) (1) to characterize them besides the lines of each single MYB gene over-expression (pap1-D and MYB12OX) by metabolome and transcriptome analysis. The flavonoid profiling exhibited that the amounts of flavonoids in WOX1 were the additive levels of anthocyanins and flavonols due to the over-expression of PAP1 and MYB12. Transcriptome analysis showed that 81 genes were specifically up-regulated in WOX1. The gene ontology analysis indicated that 57 genes, which are categorized into 'response to stimulus', were up-regulated in WOX1. Because most of them are involved in the stress response mechanism, stress experiments (salt and methyl viologen) were conducted. These experiments showed that pap1-D and WOX1 mutants exhibit the tolerance against those stresses. These results suggested the feed-forward interaction from flavonoid biosynthetic mechanism to stress mechanism.
Reference
(1) Nakabayashi R, et al., (2009) Phytochemistry, 70: 1017-1029
