One type of chalcone synthase gene expressed during embryogenesis regulates the flavonoid accumulation in citrus cell cultures.

To elucidate the relationship between the expression of chalcone synthase (CHS) genes and the production of flavonoid in citrus cell cultures, two cDNA clones encoding CHS were isolated (CitCHS1 and CitCHS2) from the citrus. The accumulation of CitCHS2 mRNA was notably induced by embryogenesis but CitCHS1 mRNA was not. There was no detectable accumulation of flavonoid in the undifferentiated calli, but flavonoid accumulated after the morphological changes to embryoids. These results indicate that two CHS genes differentially expressed during citrus somatic embryogenesis and CitCHS2 may regulate the accumulation of flavonoid in citrus cell cultures.