Provided herein are compositions and methods for improved production of steviol glycosides in a host cell. In some embodiments, the host cell is genetically modified to comprise a heterologous nucleotide sequence encoding a Pisum sativum kaurene oxidase or its variant kaurene oxidase. In some embodiments, the host cell further comprises one or more heterologous nucleotide sequence encoding further enzymes of a pathway capable of producing steviol glycosides in the host cell. The compositions and methods described herein provide an efficient route for the heterologous production of steviol glycosides, including but not limited to, rebaudioside D and rebaudioside M.