Riboflavin is the precursor of flavin mononucleotide (FMN) and flavin
adenine dinucleotide (FAD), cofactors for enzymes in biochemical reactions.
Previously, it was shown that riboflavin, FMN, and FAD levels were decreased
in leaves of transgenic Arabidopsis expressing the turtle riboflavin-binding
protein or (RfBP). Hansong Dong of Nanjing Agricultural University recently
studied the effect of flavin downregulation due to RfBP.

Early flowering was a constant phenotype of transgenic Arabidopsis. This
early flowering was correlated with enhanced expression of flower promoting
photoperiod genes in leaves. Further analysis correlated it with increased
expression of the FD gene responsible for flowering time control. When RfBP
was silenced, by contrast, the expressions of photoperiod genes in leaves
and FD were not enhanced and flavin concentrations were elevated to the
normal levels in leaves.

The results provide evidence that downregulation of leaf flavin by RfBP
induces early flowering and coincident enhancements of genes that promote
flowering through the photoperiod pathway.

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