UDP-dependent glycosyltransferase for high efficiency production of rebaudiosides
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 Setaria italica UDP-glycosyltransferase 40087 or its variant UDP-glycosyltransferase. In some embodiments, the host cell is genetically modified to comprise a heterologous nucleotide sequence encoding a UDP-glycosyltransferase sr.UGT_9252778, Bd_uGT10850, and/or Ob_UGT91B_1 like. 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.
1. A genetically modified yeast host cell comprising a heterologous nucleic acid encoding a UDP-glycosyltransferase, comprising an amino acid sequence having at least 80% sequence identity to SEQ ID NO: 1, wherein the genetically modified host cell is capable of converting rebaudioside A (RebA) to rebaudioside D (RebD) at an efficiency of greater than 90%.
2. The genetically modified host cell of claim 1 , wherein the UDP-glycosyltransferase comprises an amino acid sequence having the sequence of SEQ ID NO:1.
3. The genetically modified host cell of claim 1 , wherein the UDP-glycosyltransferase is capable of beta 1,2 glycosylation of the C2′ position of the 19-0 glucose of a steviol glycoside.
4. The genetically modified host cell of claim 1 , wherein the UDP-glycosyltransferase is encoded by a heterologous nucleic acid, wherein the heterologous nucleic acid comprises a nucleotide sequence having at least 80% sequence identity to SEQ ID NO:13.
5. The genetically modified host cell of claim 1 , wherein the UDP-glycosyltransferase is encoded by a heterologous nucleic acid having the sequence of SEQ ID NO:13.
6. The genetically modified host cell of claim 1 , that is capable of converting RebA to RebD at an efficiency of greater than 90% and wherein the UDP-glycosyltransferase comprises an amino acid sequence having at least 95% sequence identity to SEQ ID NO:l.
7. The genetically modified host cell of claim 1 , wherein the UDP-glycosyltransferase comprises the amino acid sequence SEQ ID NO:24.
8. The genetically modified host cell of claim 1 , wherein the UDP-glycosyltransferase comprises an amino acid sequence having at least 92% sequence identity to SEQ ID NO:l.
9. The genetically modified host cell of claim 1 that is capable of producing RebD.
10. The genetically modified host cell of claim 1 that is capable of producing rebaudioside M (RebM).
11. The genetically modified host cell of claim 1 that is capable of producing at RebM and rebaudioside M2 (RebM2) at a ratio of at least 10:1, 100:1, or 1000:1.
12. The genetically modified host cell of claim 1 , wherein the genetically modified host cell produces an undetectable level of RebM2.
13. The genetically modified host cell of claim 1 , wherein the genetically modified host cell is capable of converting stevioside to rebaudioside E (RebE).
14. The genetically modified host cell of claim 1 , wherein the genetically modified host cell further comprises one or more heterologous nucleic acids encoding one or more enzymes of a pathway for making steviol.
15. The genetically modified host cell of claim 1 , wherein the genetically modified host cell further comprises one or more heterologous nucleic acids encoding one or more enzymes of a pathway for making a steviol glycoside.
16. The genetically modified host cell of claim 1 , wherein the genetically modified host cell further comprises one or more heterologous nucleic acids encoding one or more enzymes of a pathway for making a RebA.
17. The genetically modified host cell of claim 1 , wherein the genetically modified host cell further comprises one or more heterologous nucleic acids encoding one or more enzymes of a pathway for making RebM.
18. The genetically modified host cell of claim 1 , wherein the genetically modified host cell further comprises one or more heterologous nucleic acids encoding one or more enzymes of a pathway for making RebE.
19. The genetically modified host cell of claim 14 , wherein the one or more enzymes of the pathway comprise a geranylgeranyl diphosphate synthase.
20. The genetically modified host cell of claim 14 , wherein the one or more enzymes of the pathway comprise a copalyl diphosphate synthase.
21. The genetically modified host cell of claim 14 , wherein the one or more enzymes of the pathway comprise an ent-kaurene synthase.
22. The genetically modified host cell of claim 14 , wherein the one or more enzymes of the pathway comprise a kaurene oxidase.
23. The genetically modified host cell of claim 14 , wherein the one or more enzymes of the pathway comprise a kaurenoic acid hydroxylase.
24. The genetically modified host cell of claim 14 , wherein the one or more enzymes of the pathway comprise a cytochrome P450 reductase.
25. The genetically modified host cell of claim 15 , wherein the one or more enzymes of the pathway comprise a uridine 5′-diphospho glycosyltransferase.
26. The genetically modified host cell of claim 15 , wherein the one or more enzymes of the pathway comprise UGT74G1 (SEQ ID NO: 31), UGT76G1 (SEQ ID NO: 32), UGT85C2 (SEQ ID NO: 33), and UGT91D (SEQ ID NO:7).
27. The genetically modified host cell of claim 15 , wherein the one or more enzymes of the pathway comprise a geranylgeranyl diphosphate synthase, a copalyl diphosphate synthase, a ent-kaurene synthase, a kaurene oxidase, a kaurenoic acid hydroxylase, a cytochrome P450 reductase, UGT74G1 (SEQ ID NO: 31), UGT76G1 (SEQ ID NO: 32), UGT85C2 (SEQ ID NO: 33), and UGT91D (SEQ ID NO:7).
28. The genetically modified host cell of claim 14 , wherein the one or more enzymes of the pathway comprises a bifunctional copalyl diphosphate synthase and kaurene synthase.
29. The genetically modified host cell of claim 27 , wherein the one or more heterologous nucleic acids encoding one or more enzymes of the pathway are under control of a single transcriptional regulator.
30. The genetically modified host cell of claim 27 , wherein the one or more heterologous nucleic acids encoding one or more enzymes of the pathway are under control of multiple heterologous transcriptional regulators.
31. The genetically modified host cell of claim 1 , wherein the yeast is Saccharomyces cerevisiae.
32. A method for producing RebD:
(a) culturing a population of the genetically modified host cells claim 1 in a medium with a carbon source under conditions suitable for making RebD; and
(b) recovering said RebD compound from the medium.
33. A method for producing RebM:
(a) culturing a population of the genetically modified host cells claim 1 in a medium with a carbon source under conditions suitable for making RebM; and
(b) recovering said RebM compound from the medium.
34. The genetically modified host cell of claim 1 , comprising a heterologous nucleic acid encoding a UDP-glycosyltransferase comprising an amino acid sequence having at least 85% sequence identity to SEQ ID NO:l.
35. The genetically modified host cell of claim 1 , comprising a heterologous nucleic acid encoding a UDP-glycosyltransferase comprising an amino acid sequence having at least 90%, sequence identity to SEQ ID NO:l.
36. The genetically modified host cell of claim 1 , comprising a heterologous nucleic acid encoding a UDP-glycosyltransferase comprising an amino acid sequence having at least 95% sequence identity to SEQ ID NO:l.
37. The genetically modified host cell of claim 1 , wherein the UDP-glycosyltransferase is encoded by a heterologous nucleic acid, wherein the heterologous nucleic acid comprises a nucleotide sequence having at least 85% sequence identity to SEQ ID NO:13.
38. The genetically modified host cell of claim 1 , wherein the UDP-glycosyltransferase is encoded by a heterologous nucleic acid, wherein the heterologous nucleic acid comprises a nucleotide sequence having at least 90% sequence identity to SEQ ID NO:13.
39. The genetically modified host cell of claim 1 , wherein the UDP-glycosyltransferase is encoded by a heterologous nucleic acid, wherein the heterologous nucleic acid comprises a nucleotide sequence having at least 95% sequence identity to SEQ ID NO:13.