title: Comparison of drought stress response and gene expression between a GM maize variety and a near-isogenic non-GM variety.
abstract: Maize MON810, grown and commercialised worldwide, is the only cultivated GM event in the EU. Maize MON810, variety DKC6575, and the corresponding near-isogenic line Tietar were studied in different growth conditions, to compare their behaviour in response to drought. Main photosynthetic parameters were significantly affected by drought stress in both GM and non-GM varieties to a similar extent. Though DKC6575 (GM) had a greater sensitivity in the early phase of stress response as compared with Tietar (non-GM), after six days of stress they behaved similarly, and both varieties recovered from stress damage. Profiling gene expression in water deficit regimes and in a generalised drought stress condition showed an up-regulation of many stress-responsive genes, but a greater number of differentially expressed genes was observed in Tietar, with genes belonging to transcription factor families and genes encoding heat shock proteins, late embryogenesis abundant proteins and detoxification enzymes. Since induction of these genes have been indicated from the literature as typical of stress responses, their activation in Tietar rather than in DKC6575 may be reminiscent of a more efficient response to drought. DKC6575 was also analysed for the expression of the transgene CryIAb (encoding the delta-endotoxin insecticidal protein) in water deficit conditions. In all the experiments, the CryIAb transcript was not influenced by drought stress, but was expressed at a constant level. This suggests that though possessing a different pattern of sensitivity to stress, the GM variety maintains the same expression level for the transgene.
authors.affiliation: Department of Life Sciences, University of Parma, Parco Area delle Scienze 11a, 43124 Parma, Italy.
authors.forename: Mariolina
authors.initials: M
authors.lastname: Gullì
authors.affiliation: Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Salvatori
authors.affiliation: Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
authors.forename: Lina
authors.initials: L
authors.lastname: Fusaro
authors.affiliation: Department of Life Sciences, University of Parma, Parco Area delle Scienze 11a, 43124 Parma, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Pellacani
authors.affiliation: Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
authors.forename: Fausto
authors.initials: F
authors.lastname: Manes
authors.affiliation: Department of Life Sciences, University of Parma, Parco Area delle Scienze 11a, 43124 Parma, Italy.
authors.forename: Nelson
authors.initials: N
authors.lastname: Marmiroli
mesh_terms: D055864:Droughts; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics; D003313:Zea mays / Q000235:genetics*