title: Salt stress induces differential regulation of the phenylpropanoid pathway in Olea europaea cultivars Frantoio (salt-tolerant) and Leccino (salt-sensitive).
abstract: Olive tree (Olea europaea L.) is an important crop in the Mediterranean Basin where drought and salinity are two of the main factors affecting plant productivity. Despite several studies have reported different responses of various olive tree cultivars to salt stress, the mechanisms that convey tolerance and sensitivity remain largely unknown. To investigate this issue, potted olive plants of Leccino (salt-sensitive) and Frantoio (salt-tolerant) cultivars were grown in a phytotron chamber and treated with 0, 60 and 120mM NaCl. After forty days of treatment, growth analysis was performed and the concentration of sodium in root, stem and leaves was measured by atomic absorption spectroscopy. Phenolic compounds were extracted using methanol, hydrolyzed with butanol-HCl, and quercetin and kaempferol quantified via high performance liquid-chromatography-electrospray-mass spectrometry (HPLC-ESI-MS) and HPLC-q-Time of Flight-MS analyses. In addition, the transcripts levels of five key genes of the phenylpropanoid pathway were measured by quantitative Real-Time PCR. The results of this study corroborate the previous observations, which showed that Frantoio and Leccino differ in allocating sodium in root and leaves. This study also revealed that phenolic compounds remain stable or are strongly depleted under long-time treatment with sodium in Leccino, despite a strong up-regulation of key genes of the phenylpropanoid pathway was observed. Frantoio instead, showed a less intense up-regulation of the phenylpropanoid genes but overall higher content of phenolic compounds. These data suggest that Frantoio copes with the toxicity imposed by elevated sodium not only with mechanisms of Na+exclusion, but also promptly allocating effective and adequate antioxidant compounds to more sensitive organs.
authors: BioLabs, Institute of Life Sciences, Scuola Superiore Sant'Anna, I-56127 Pisa, Italy; Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors: Lorenzo
authors: L
authors: Rossi
authors: Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors: Monica
authors: M
authors: Borghi
authors: BioLabs, Institute of Life Sciences, Scuola Superiore Sant'Anna, I-56127 Pisa, Italy.
authors: Alessandra
authors: A
authors: Francini
authors: Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors: Xiuli
authors: X
authors: Lin
authors: Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors: De-Yu
authors: DY
authors: Xie
authors: BioLabs, Institute of Life Sciences, Scuola Superiore Sant'Anna, I-56127 Pisa, Italy. Electronic address: luca.sebastiani@sssup.it.
authors: Luca
authors: L
authors: Sebastiani
mesh_terms: D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D044949:Kaempferols / Q000032:analysis; D053858:Metabolic Networks and Pathways / Q000187:drug effects* / Q000235:genetics; D031658:Olea / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D009928:Organ Specificity / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D018547:Plant Stems / Q000187:drug effects / Q000378:metabolism; D020005:Propanols / Q000378:metabolism*; D011794:Quercetin / Q000032:analysis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D055049:Salt Tolerance / Q000187:drug effects* / Q000235:genetics; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000187:drug effects*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D044949:Kaempferols; D020005:Propanols; D012333:RNA, Messenger; C439395:1-phenylpropanol; D012965:Sodium Chloride; C006552:kaempferol; D011794:Quercetin; D012964:Sodium
keywords: Gene-expression; Kaempferol; Olive tree; Quercetin; Salinity