title: RNAi down-regulation of cinnamate-4-hydroxylase increases artemisinin biosynthesis in Artemisia annua.
abstract: Cinnamate-4-hydroxylase (C4H) converts trans-cinnamic acid (CA) to p-coumaric acid (COA) in the phenylpropanoid/lignin biosynthesis pathway. Earlier we reported increased expression of AaCYP71AV1 (an important gene of artemisinin biosynthesis pathway) caused by CA treatment in Artemisia annua. Hence, AaC4H gene was identified, cloned, characterized and silenced in A. annua with the assumption that the elevated internal CA due to knock down may increase the artemisinin yield. Accumulation of trans-cinnamic acid in the plant due to AaC4H knockdown was accompanied with the reduction of p-coumaric acid, total phenolics, anthocyanin, cinnamate-4-hydroxylase (C4H) and phenylalanine ammonia lyase (PAL) activities but increase in salicylic acid (SA) and artemisinin. Interestingly, feeding trans-cinnamic acid to the RNAi line increased the level of artemisinin along with benzoic (BA) and SA with no effect on the downstream metabolites p-coumaric acid, coniferylaldehyde and sinapaldehyde, whereas p-coumaric acid feeding increased the content of downstream coniferylaldehyde and sinapaldehyde with no effect on BA, SA, trans-cinnamic acid or artemisinin. SA is reported earlier to be inducing the artemisinin yield. This report demonstrates the link between the phenylpropanoid/lignin pathway with artemisinin pathway through SA, triggered by accumulation of trans-cinnamic acid because of the blockage at C4H.
authors.affiliation: Biotechnology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow-226015, U.P., India.
authors.forename: Ritesh
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Biotechnology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow-226015, U.P., India.
authors.forename: Divya
authors.initials: D
authors.lastname: Vashisth
authors.affiliation: Biotechnology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow-226015, U.P., India.
authors.forename: Amita
authors.initials: A
authors.lastname: Misra
authors.affiliation: Biotechnology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow-226015, U.P., India.
authors.forename: Md Qussen
authors.initials: MQ
authors.lastname: Akhtar
authors.affiliation: Biotechnology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow-226015, U.P., India.
authors.forename: Syed Uzma
authors.initials: SU
authors.lastname: Jalil
authors.affiliation: Analytical Chemistry Division, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow-226015, U.P., India.
authors.forename: Karuna
authors.initials: K
authors.lastname: Shanker
authors.affiliation: Analytical Chemistry Division, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow-226015, U.P., India.
authors.forename: Madan Mohan
authors.initials: MM
authors.lastname: Gupta
authors.affiliation: Chemical Sciences Division, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow-226015, U.P., India.
authors.forename: Prashant Kumar
authors.initials: PK
authors.lastname: Rout
authors.affiliation: Genetics and Plant Breeding Division, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow-226015, U.P., India.
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Gupta
authors.affiliation: Biotechnology Division, CSIR-Central Institute of Medicinal and Aromatic Plants, P.O. CIMAP, Lucknow-226015, U.P., India.
authors.forename: Ajit Kumar
authors.initials: AK
authors.lastname: Shasany
mesh_terms: D031172:Artemisia annua / Q000201:enzymology* / Q000235:genetics; D037621:Artemisinins / Q000378:metabolism*; D015536:Down-Regulation; D055785:Gene Knockdown Techniques; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D013312:Stress, Physiological; D050564:Trans-Cinnamate 4-Monooxygenase / Q000235:genetics* / Q000378:metabolism
chemical_list: D037621:Artemisinins; D010940:Plant Proteins; D050564:Trans-Cinnamate 4-Monooxygenase