title: Nitric oxide and brassinosteroids mediated fungal endophyte-induced volatile oil production through protein phosphorylation pathways in Atractylodes lancea plantlets.
abstract: Fungal endophytes have been isolated from almost every plant, infecting their hosts without causing visible disease symptoms, and yet have still proved to be involved in plant secondary metabolites accumulation. To decipher the possible physiological mechanisms of the endophytic fungus-host interaction, the role of protein phosphorylation and the relationship between endophytic fungus-induced kinase activity and nitric oxide (NO) and brassinolide (BL) in endophyte-enhanced volatile oil accumulation in Atractylodes lancea plantlets were investigated using pharmacological and biochemical approaches. Inoculation with the endophytic fungus Gilmaniella sp. AL12 enhanced the activities of total protein phosphorylation, Ca²⁺-dependent protein kinase, and volatile oil accumulation in A. lancea plantlets. The upregulation of protein kinase activity could be blocked by the BL inhibitor brassinazole. Furthermore, pretreatments with the NO-specific scavenger cPTIO significantly reduced the increased activities of protein kinases in A. lancea plantlets inoculated with endophytic fungus. Pretreatments with different protein kinase inhibitors also reduced fungus-induced NO production and volatile oil accumulation, but had barely no effect on the BL level. These data suggest that protein phosphorylation is required for endophyte-induced volatile oil production in A. lancea plantlets, and that crosstalk between protein phosphorylation and the NO pathway may occur and act as a downstream signaling event of the BL pathway.
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences in Nanjing Normal University, Nanjing, 210023, China.
authors.forename: Cheng-Gang
authors.initials: CG
authors.lastname: Ren
authors.forename: Chuan-Chao
authors.initials: CC
authors.lastname: Dai
mesh_terms: D031174:Atractylodes / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology; D060406:Brassinosteroids / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D060026:Endophytes / Q000187:drug effects / Q000502:physiology*; D004789:Enzyme Activation / Q000187:drug effects; D005658:Fungi / Q000187:drug effects / Q000502:physiology*; D008954:Models, Biological; D009569:Nitric Oxide / Q000494:pharmacology*; D009822:Oils, Volatile / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D010940:Plant Proteins / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism
chemical_list: D060406:Brassinosteroids; D009822:Oils, Volatile; D010940:Plant Proteins; D047428:Protein Kinase Inhibitors; D009569:Nitric Oxide; D011494:Protein Kinases; D002118:Calcium
keywords: Atractylodes lancea; endophytic fungus; protein phosphorylation; signal molecule; volatile oil