The present invention provides a method for enhancing the overall pathway of polyisoprenoid biosynthesis. The present invention further provides an isoprenoid-producing plant having an overall enhanced pathway of polyisoprenoid biosynthesis, and a method for producing polyisoprenoids using such an isoprenoid-producing plant. The present invention relates to a method for regulating by a light-responsive transcription factor the expression of at least one protein selected from the group consisting of hydroxymethylglutaryl-CoA reductase, isopentenyl diphosphate isomerase, cis-prenyltransferase, and small rubber particle protein.
