title: Metabolic response to cold and freezing of Osteospermum ecklonis overexpressing Osmyb4.
abstract: The constitutive expression of the rice Osmyb4 gene in Arabidopsis plants gives rise to enhanced abiotic and biotic stress tolerance, probably by activating several stress-inducible pathways. However, the effect of Osmyb4 on stress tolerance likely depends on the genetic background of the transformed species. In this study, we explored the potential of Osmyb4 to enhance the cold and freezing tolerance of Osteospermum ecklonis, an ornamental and perennial plant native to South Africa, because of an increasing interest in growing this species in Europe where winter temperatures are low. Transgenic O. ecklonis plants were obtained through transformation with the Osmyb4 rice gene under the control of the CaMV35S promoter. We examined the phenotypic adaptation of transgenic plants to cold and freezing stress. We also analysed the ability of wild-type and transgenic Osteospermum to accumulate several solutes, such as proline, amino acids and sugars. Using nuclear magnetic resonance, we outlined the metabolic profile of this species under normal growth conditions and under stress for the first time. Indeed, we found that overexpression of Osmyb4 improved the cold and freezing tolerance and produced changes in metabolite accumulation, especially of sugars and proline. Based on our data, it could be of agronomic and economic interest to use this gene to produce Osteospermum plants capable of growing in open field, even during the winter season in climatic zone Z9.
authors.affiliation: Unità di Ricerca per la Floricoltura e le Specie Ornamentali, Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Corso Degli Inglesi 508, 18038 Sanremo (IM), Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Laura
authors.forename: Roberto
authors.initials: R
authors.lastname: Consonni
authors.forename: Franca
authors.initials: F
authors.lastname: Locatelli
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Fumagalli
authors.forename: Andrea
authors.initials: A
authors.lastname: Allavena
authors.forename: Immacolata
authors.initials: I
authors.lastname: Coraggio
authors.forename: Monica
authors.initials: M
authors.lastname: Mattana
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000596:Amino Acids / Q000378:metabolism; D019659:Asteraceae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D002241:Carbohydrates / Q000032:analysis; D003080:Cold Temperature; D005060:Europe; D005615:Freezing; D009682:Magnetic Resonance Spectroscopy; D012275:Oryza / Q000235:genetics; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D025341:Principal Component Analysis; D011392:Proline / Q000378:metabolism; D013019:South Africa; D013312:Stress, Physiological
chemical_list: D000596:Amino Acids; D002241:Carbohydrates; D010940:Plant Proteins; D011392:Proline