Modified CAROTENOID CLEAVAGE DIOXYGENASE8 expression correlates with altered branching in kiwifruit (Actinidia chinensis)

P>CAROTENOID CLEAVAGE DIOXYGENASE (CCD) genes have been demonstrated to play an integral role in the control of branch development in model plants, including Arabidopsis, pea (Pisum sativum), petunia (Petunia hybrida) and rice (Oryza sativa). Actinidia chinensis is a woody perennial plant grown for commercial production of kiwifruit. CCD7 and CCD8 genes were isolated from A. chinensis and these genes are predominantly expressed in the roots of kiwifruit. AcCCD7 and AcCCD8 were able to complement the corresponding Arabidopsis mutants max3 and max4. The function of AcCCD8 in branch development was determined in transgenic kiwifruit plants containing an RNAi construct for AcCCD8. Reduction in expression of AcCCD8 correlated with an increase in branch development and delayed leaf senescence. The CCD pathway for control of branch development is conserved across a wide range of species, including kiwifruit, a woody perennial.