passages.id: split_5_test_2895_passage
passages.type: progene_text
passages.text: We have compared expression levels of four key terpenoid biosynthetic genes : 3-hydroxy-3-methylglutaryl coenzyme A reductase ( HMGR ) , 1-deoxy-D-xylulose-5-phosphate synthase ( DXS ) , 1-deoxy-D-xylulose-5-phosphate reductoisomerase ( DXR ) , and farnesyl diphosphate synthase ( FPS ) in the three culture conditions .