APETALA2-like Floral Homeotic Protein Up-Regulating Gene Involved in Floral Development in Long-Homostyle Common Buckwheat.

In the rosid species , the AP2-type AP2 transcription factor (TF) is required for specifying the sepals and petals identities and confers a major A-function to antagonize the C-function in the outer floral whorls. In the asterid species , the AP2-type ROB TFs are required for perianth and pistil development, as well as repressing the B-function together with TOE-type TF BEN. In Long-homostyle (LH) , VIGS-silencing showed that is mainly involved in controlling filament and style length, but is mainly involved in regulating filament length and pollen grain development. Both (AP2-type) and (TOE-type) are redundantly involved in style and/or filament length determination instead of perianth development. However, neither nor could directly repress the B and/or C class genes in common buckwheat. Moreover, the silenced flower showed tepal numbers, and filament length decreased obviously. Interestingly, yeast one-hybrid (Y1H) and dual-luciferase reporter (DR) further suggested that directly up-regulates to be involved in filament length determination in LH common buckwheat. Moreover, the knockdown of expression could result in expression down-regulation of the directly target in the -silenced LH plants. Our findings uncover a stamen development pathway in common buckwheat and offer deeper insight into the functional evolution of AP2 orthologs in the early-diverging core eudicots.