title: Deregulation of apoplastic polyamine oxidase affects development and salt response of tobacco plants.
abstract: Polyamine (PA) homeostasis is associated with plant development, growth and responses to biotic/abiotic stresses. Apoplastic PA oxidase (PAO) catalyzes the oxidation of PAs contributing to cellular homeostasis of reactive oxygen species (ROS) and PAs. In tobacco, PAs decrease with plant age, while apoplastic PAO activity increases. Our previous results with young transgenic tobacco plants with enhanced/reduced apoplastic PAO activity (S-ZmPAO/AS-ZmPAO, respectively) established the importance of apoplastic PAO in controlling tolerance to short-term salt stress. However, it remains unclear if the apoplastic PAO pathway is important for salt tolerance at later stages of plant development. In this work, we examined whether apoplastic PAO controls also plant development and tolerance of adult plants during long-term salt stress. The AS-ZmPAO plants contained higher Ca2+during salt stress, showing also reduced chlorophyll content index (CCI), leaf area and biomass but taller phenotype compared to the wild-type plants during salt. On the contrary, the S-ZmPAO had more leaves with slightly greater size compared to the AS-ZmPAO and higher antioxidant genes/enzyme activities. Accumulation of proline in the roots was evident at prolonged stress and correlated negatively with PAO deregulation as did the transcripts of genes mediating ethylene biosynthesis. In contrast to the strong effect of apoplastic PAO to salt tolerance in young plants described previously, the effect it exerts at later stages of development is rather moderate. However, the different phenotypes observed in plants deregulating PAO reinforce the view that apoplastic PAO exerts multifaceted roles on plant growth and stress responses. Our data suggest that deregulation of the apoplastic PAO can be further examined as a potential approach to breed plants with enhanced/reduced tolerance to abiotic stress with minimal associated trade-offs.
authors.affiliation: Department of Biology, University of Crete, Voutes University Campus, 70013 Heraklion, Greece; Biological Research Centre, Hungarian Academy of Sciences, H-6726 Szeged, Temesvari krt. 62, Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Gémes
authors.affiliation: School of Agriculture, Aristotle University, 54124 Thessaloniki, Greece.
authors.forename: Ιfigeneia
authors.initials: Ι
authors.lastname: Mellidou
authors.affiliation: School of Agriculture, Aristotle University, 54124 Thessaloniki, Greece.
authors.forename: Katerina
authors.initials: K
authors.lastname: Karamanoli
authors.affiliation: Department of Biology, National and Kapodistrian University of Athens, Greece.
authors.forename: Despoina
authors.initials: D
authors.lastname: Beris
authors.affiliation: Department of Biology, Sunchon National University, 57922 Chonnam, South Korea.
authors.forename: Ky Young
authors.initials: KY
authors.lastname: Park
authors.affiliation: School of Agriculture, Aristotle University, 54124 Thessaloniki, Greece.
authors.forename: Theodora
authors.initials: T
authors.lastname: Matsi
authors.affiliation: Department of Biology, National and Kapodistrian University of Athens, Greece.
authors.forename: Kosmas
authors.initials: K
authors.lastname: Haralampidis
authors.affiliation: School of Agriculture, Aristotle University, 54124 Thessaloniki, Greece. Electronic address: constad@agro.auth.gr.
authors.forename: Helen-Isis
authors.initials: HI
authors.lastname: Constantinidou
authors.affiliation: Department of Biology, University of Crete, Voutes University Campus, 70013 Heraklion, Greece. Electronic address: poproube@biology.uoc.gr.
authors.forename: Kalliopi A
authors.initials: KA
authors.lastname: Roubelakis-Angelakis
mesh_terms: D060387:Ascorbate Peroxidases / Q000378:metabolism; D018533:Biomass; D053898:Biosynthetic Pathways / Q000187:drug effects / Q000235:genetics; D002374:Catalase / Q000378:metabolism; D004573:Electrolytes / Q000378:metabolism; D005030:Ethylenes / Q000096:biosynthesis; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D006706:Homeostasis / Q000187:drug effects; D007477:Ions; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000378:metabolism*; D010636:Phenols / Q000032:analysis; D010641:Phenotype; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D030821:Plants, Genetically Modified; D011392:Proline / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D013482:Superoxide Dismutase / Q000378:metabolism; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000502:physiology*; D003313:Zea mays / Q000201:enzymology*; D000097667:Polyamine Oxidase
chemical_list: D060387:Ascorbate Peroxidases; D002374:Catalase; D004573:Electrolytes; D005030:Ethylenes; D007477:Ions; D000587:Oxidoreductases Acting on CH-NH Group Donors; D010636:Phenols; D011392:Proline; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D012965:Sodium Chloride; D013482:Superoxide Dismutase; D000097667:Polyamine Oxidase; C036216:ethylene
keywords: Ion content under salinity; Net photosynthesis; Oxidative stress; Polyamine oxidase; Salt tolerance; Sense/antisense PAO transgenics