title: Flavonol Glucoside and Antioxidant Enzyme Biosynthesis Affected by Mycorrhizal Fungi in Various Cultivars of Onion (Allium cepa L.).
abstract: The objective of this study was to investigate the impact of mycorrhizal symbiosis on qualitative characteristics of onion (Allium cepa L.). For this reason, five onion cultivars with different scale color and three different strains of arbuscular mycorrhizal fungi (Diversispora versiformis, Rhizophagus intraradices, Funneliformis mosseae) were used. Red cultivars, mainly 'Red Azar-shahr', showed the highest content in vitamin C, flavonols, and antioxidant enzymes. Mycorrhizal inoculation increased total phenolic, pyruvic acid, and vitamin C of onion plants. Considerable increase was observed in quercetin-4'-O-monoglucoside and isorhamnetin-4'-O-monoglucoside content in plants inoculated with Diversispora versiformis, but quercetin-3,4'-O-diglucoside was not significantly influenced. Analyses for phenylalanine ammonia-lyase (PAL) and antioxiodant enzyme activities such as polyphenol oxidase (PPO), catalase (CAT), and peroxidase (POD) revealed that all except PPO were enhanced by mycorrhizal inoculation. Overall, these findings suggested that mycorrhizal inoculation influenced biosynthesis of flavonol glucosides and antioxidant enzymes by increasing nutrient uptake or by induction of the plant defense system.
authors.affiliation: Department of Horticulture, Faculty of Agriculture, University of Tabriz , Tabriz, Iran.
authors.forename: Mohanna
authors.initials: M
authors.lastname: Mollavali
authors.affiliation: Department of Horticulture, Faculty of Agriculture, University of Tabriz , Tabriz, Iran.
authors.forename: Saheb Ali
authors.initials: SA
authors.lastname: Bolandnazar
authors.affiliation: Leibniz Institute for Vegetable and Ornamental Crops. Theodor-Echtermeyer-Weg 1, 14979 Großbeeren, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schwarz
authors.affiliation: Institute of Food Chemistry, Hamburg School of Food Science, University of Hamburg , Grindelallee 117, 20146 Hamburg, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Rohn
authors.affiliation: Institute of Food Chemistry, Hamburg School of Food Science, University of Hamburg , Grindelallee 117, 20146 Hamburg, Germany.
authors.forename: Peer
authors.initials: P
authors.lastname: Riehle
authors.affiliation: Department of Horticulture, Faculty of Agriculture, University of Tabriz , Tabriz, Iran.
authors.forename: Fariborz
authors.initials: F
authors.lastname: Zaare Nahandi
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D004156:Catechol Oxidase / Q000378:metabolism; D044948:Flavonols / Q000032:analysis* / Q000378:metabolism; D005658:Fungi / Q000502:physiology*; D005960:Glucosides / Q000032:analysis* / Q000378:metabolism; D038821:Mycorrhizae / Q000502:physiology*; D019697:Onions / Q000737:chemistry / Q000145:classification / Q000201:enzymology / Q000382:microbiology*; D009195:Peroxidase / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D018517:Plant Roots / Q000737:chemistry / Q000201:enzymology / Q000382:microbiology
chemical_list: D000975:Antioxidants; D044948:Flavonols; D005960:Glucosides; D010940:Plant Proteins; D004156:Catechol Oxidase; D002374:Catalase; D009195:Peroxidase
keywords: AMF; phenylalanine ammonia-lyase; pyruvic acid; vitamin C