title: Rhizophagus intraradices or its associated bacteria affect gene expression of key enzymes involved in the rosmarinic acid biosynthetic pathway of basil.
abstract: In recent years, arbuscular mycorrhizal fungi (AMF) have been reported to enhance plant biosynthesis of secondary metabolites with health-promoting activities, such as polyphenols, carotenoids, vitamins, anthocyanins, flavonoids and lycopene. In addition, plant growth-promoting (PGP) bacteria were shown to modulate the concentration of nutraceutical compounds in different plant species. This study investigated for the first time whether genes encoding key enzymes of the biochemical pathways leading to the production of rosmarinic acid (RA), a bioactive compound showing antioxidant, antibacterial, antiviral and anti-inflammatory properties, were differentially expressed in Ocimum basilicum (sweet basil) inoculated with AMF or selected PGP bacteria, by using quantitative real-time reverse transcription PCR. O. basilicum plants were inoculated with either the AMF species Rhizophagus intraradices or a combination of two PGP bacteria isolated from its sporosphere, Sinorhizobium meliloti TSA41 and Streptomyces sp. W43N. Present data show that the selected PGP bacteria were able to trigger the overexpression of tyrosine amino-transferase (TAT), hydroxyphenylpyruvate reductase (HPPR) and p-coumaroyl shikimate 3'-hydroxylase isoform 1 (CS3'H iso1) genes, 5.7-fold, 2-fold and 2.4-fold, respectively, in O. basilicum leaves. By contrast, inoculation with R. intraradices triggered TAT upregulation and HPPR and CS3'H iso1 downregulation. Our data suggest that inoculation with the two selected strains of PGP bacteria utilised here could represent a suitable biotechnological tool to be implemented for the production of O. basilicum plants with increased levels of key enzymes for the biosynthesis of RA, a compound showing important functional properties as related to human health.
authors.affiliation: Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Battini
authors.affiliation: Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy.|Interdepartmental Research Center Nutrafood-Nutraceuticals and Food for Health, University of Pisa, Pisa, Italy.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Bernardi
authors.affiliation: Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy.|Interdepartmental Research Center Nutrafood-Nutraceuticals and Food for Health, University of Pisa, Pisa, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Turrini
authors.affiliation: Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy.|Interdepartmental Research Center Nutrafood-Nutraceuticals and Food for Health, University of Pisa, Pisa, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Agnolucci
authors.affiliation: Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy. manuela.giovannetti@unipi.it.|Interdepartmental Research Center Nutrafood-Nutraceuticals and Food for Health, University of Pisa, Pisa, Italy. manuela.giovannetti@unipi.it.
authors.forename: Manuela
authors.initials: M
authors.lastname: Giovannetti
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D002934:Cinnamates / Q000737:chemistry / Q000378:metabolism*; D053630:Depsides / Q000737:chemistry / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D055137:Glomeromycota / Q000502:physiology*; D015394:Molecular Structure; D018649:Ocimum basilicum / Q000378:metabolism* / Q000382:microbiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D012337:RNA, Ribosomal, 18S / Q000235:genetics / Q000378:metabolism; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism; D000097123:Rosmarinic Acid
chemical_list: D002934:Cinnamates; D053630:Depsides; D010940:Plant Proteins; D018749:RNA, Plant; D012337:RNA, Ribosomal, 18S; D025801:Ubiquitin; D000097123:Rosmarinic Acid
keywords: Arbuscular mycorrhizal fungi; Hydroxyphenylpyruvate reductase expression levels; Rhizophagus intraradices; Rosmarinic acid; Spore-associated bacteria; Tyrosine amino-transferase expression levels