title: Arbuscular mycorrhiza increase artemisinin accumulation in Artemisia annua by higher expression of key biosynthesis genes via enhanced jasmonic acid levels.
abstract: It is becoming increasingly evident that the formation of arbuscular mycorrhiza (AM) enhances secondary metabolite production in shoots. Despite mounting evidence, relatively little is known about the underlying mechanisms. This study suggests that increase in artemisinin concentration in Artemisia annua colonized by Rhizophagus intraradices is due to altered trichome density as well as transcriptional patterns that are mediated via enhanced jasmonic acid (JA) levels. Mycorrhizal (M) plants had higher JA levels in leaf tissue that may be due to induction of an allene oxidase synthase gene (AOS), encoding one of the key enzymes for JA production. Non-mycorrhizal (NM) plants were exogenously supplied with a range of methyl jasmonic acid concentrations. When leaves of NM and M plants with similar levels of endogenous JA were compared, these matched closely in terms of shoot trichome density, artemisinin concentration, and transcript profile of artemisinin biosynthesis genes. Mycorrhization increased artemisinin levels by increasing glandular trichome density and transcriptional activation of artemisinin biosynthesis genes. Transcriptional analysis of some rate-limiting enzymes of mevalonate and methyl erythritol phosphate (MEP) pathways revealed that AM increases isoprenoids by induction of the MEP pathway. A decline in artemisinin concentration in shoots of NM and M plants treated with ibuprofen (an inhibitor of JA biosynthesis) further confirmed the implication of JA in the mechanism of artemisinin production.
authors.affiliation: Department of Botany, University of Delhi, Delhi, 110007, India.
authors.forename: Shantanu
authors.initials: S
authors.lastname: Mandal
authors.forename: Shivangi
authors.initials: S
authors.lastname: Upadhyay
authors.forename: Saima
authors.initials: S
authors.lastname: Wajid
authors.forename: Mauji
authors.initials: M
authors.lastname: Ram
authors.forename: Dharam Chand
authors.initials: DC
authors.lastname: Jain
authors.forename: Ved Pal
authors.initials: VP
authors.lastname: Singh
authors.forename: Malik Zainul
authors.initials: MZ
authors.lastname: Abdin
authors.forename: Rupam
authors.initials: R
authors.lastname: Kapoor
mesh_terms: D031172:Artemisia annua / Q000382:microbiology* / Q000502:physiology*; D037621:Artemisinins / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000235:genetics; D003517:Cyclopentanes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000378:metabolism; D038821:Mycorrhizae / Q000502:physiology*; D054883:Oxylipins / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000382:microbiology
chemical_list: D037621:Artemisinins; D003517:Cyclopentanes; D054883:Oxylipins; D010940:Plant Proteins; C011006:jasmonic acid; C031327:artemisinin; D019746:Intramolecular Oxidoreductases; C021377:hydroperoxide isomerase