title: Tobacco susceptibility to Potato virus Y(NTN) infection is affected by grafting and endogenous cytokinin content.
abstract: Faster or stronger response to pathogen occurs if plants undergo prior priming. Cytokinins seem to be also involved in plant priming and in response to pathogens. Susceptibility to Potato virus Y(NTN) (PVY(NTN)) was studied in transgenic cytokinin overproducing (Pssu-ipt) tobacco and compared with nontransgenic plants. Since cytokinin overproduction inhibits development of plant roots and grafting overcomes this limitation, both types were grown as rooted and/or grafted plants to check also the effect of grafting. Control rooted tobacco (C), the most susceptible to PVY(NTN), showed always symptoms during the infection together with the rising virus content and a systemic response, such as accumulation of H2O2, salicylic acid (SA) and other phenolic acids, and stress-induced enzyme activities. In transgenic and grafted plants, the response to PVY(NTN) was dependent on protective mechanisms activated prior to the inoculation. In Pssu-ipt tobacco, cytokinin active forms and SA contents exceeded manifold their content in C. Grafting promoted the accumulation of phenolics, but SA, and stimulated peroxidase activities. Thus, the pre-infection barrier established in both transgenic and grafted plants helped to suppress partly the virus multiplication and resulted in milder symptom development. However, only the synergic effect of both grafting and the high cytokinins led to PVY(NTN) tolerance in transgenic grafts. Possible mechanisms were discussed.
authors.affiliation: Institute of Experimental Botany, Academy of Sciences of the CR, Rozvojová 313, CZ-165 02 Praha 6, Czech Republic; Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, CZ-128 43 Praha 2, Czech Republic.
authors.forename: Petra
authors.initials: P
authors.lastname: Spoustová
authors.affiliation: Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Praha 2, Czech Republic.
authors.forename: Veronika
authors.initials: V
authors.lastname: Hýsková
authors.affiliation: Institute of Experimental Botany, Academy of Sciences of the CR, Rozvojová 313, CZ-165 02 Praha 6, Czech Republic.
authors.forename: Karel
authors.initials: K
authors.lastname: Müller
authors.affiliation: Institute of Experimental Botany, Academy of Sciences of the CR, Rozvojová 313, CZ-165 02 Praha 6, Czech Republic.
authors.forename: Renata
authors.initials: R
authors.lastname: Schnablová
authors.affiliation: Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Praha 2, Czech Republic.
authors.forename: Helena
authors.initials: H
authors.lastname: Ryšlavá
authors.affiliation: Institute of Experimental Botany, Academy of Sciences of the CR, Rozvojová 313, CZ-165 02 Praha 6, Czech Republic.
authors.forename: Noemi
authors.initials: N
authors.lastname: Čeřovská
authors.affiliation: Institute of Experimental Botany, Academy of Sciences of the CR, Rozvojová 313, CZ-165 02 Praha 6, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Malbeck
authors.affiliation: Institute of Experimental Botany, Academy of Sciences of the CR, Rozvojová 313, CZ-165 02 Praha 6, Czech Republic.
authors.forename: Milena
authors.initials: M
authors.lastname: Cvikrová
authors.affiliation: Institute of Experimental Botany, Academy of Sciences of the CR, Rozvojová 313, CZ-165 02 Praha 6, Czech Republic. Electronic address: synkova@ueb.cas.cz.
authors.forename: Helena
authors.initials: H
authors.lastname: Synková
mesh_terms: D000383:Agriculture / Q000379:methods*; D002678:Chimera; D003583:Cytokinins / Q000235:genetics / Q000378:metabolism*; D060467:Disease Resistance; D054884:Host-Pathogen Interactions; D006861:Hydrogen Peroxide / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D010935:Plant Diseases; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves; D018517:Plant Roots; D030821:Plants, Genetically Modified; D017800:Potyvirus; D020156:Salicylic Acid / Q000378:metabolism; D011198:Solanum tuberosum; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism / Q000821:virology*
chemical_list: D003583:Cytokinins; D010937:Plant Growth Regulators; D006861:Hydrogen Peroxide; D009195:Peroxidase; D020156:Salicylic Acid
keywords: Antioxidant system; Cytokinin; Malic enzyme; Peroxidase; Salicylic acid; ipt gene