title: The Combination ofTrichoderma harzianumand Chemical Fertilization Leads to the Deregulation of Phytohormone Networking, Preventing the Adaptive Responses of Tomato Plants to Salt Stress.
abstract: Plants have evolved effective mechanisms to avoid or reduce the potential damage caused by abiotic stresses. In addition to biocontrol abilities,Trichodermagenus fungi promote growth and alleviate the adverse effects caused by saline stress in plants. Morphological, physiological, and molecular changes were analyzed in salt-stressed tomato plants grown under greenhouse conditions in order to investigate the effects of chemical and biological fertilizations. The application ofTrichoderma harzianumT34 to tomato seeds had very positive effects on plant growth, independently of chemical fertilization. The application of salt stress significantly changed the parameters related to growth and gas-exchange rates in tomato plants subject to chemical fertilization. However, the gas-exchange parameters were not affected in unfertilized plants under the same moderate saline stress. The combined application of T34 and salt significantly reduced the fresh and dry weights of NPK-fertilized plants, while the opposite effects were detected when no chemical fertilization was applied. Decaying symptoms were observed in salt-stressed and chemically fertilized plants previously treated with T34. This damaged phenotype was linked to significantly higher intercellular CO2and slight increases in stomatal conductance and transpiration, and to the deregulation of phytohormone networking in terms of significantly lower expression levels of the salt overlay sensitivity 1 (SOS1) gene, and the genes involved in signaling abscisic acid-, ethylene-, and salicylic acid-dependent pathways and ROS production, in comparison with those observed in salt-challenged NPK-fertilized plants.
authors.affiliation: Spanish-Portuguese Institute for Agricultural Research (CIALE), Department of Microbiology and Genetics, University of Salamanca Salamanca, Spain.
authors.forename: M B
authors.initials: MB
authors.lastname: Rubio
authors.affiliation: Spanish-Portuguese Institute for Agricultural Research (CIALE), Department of Microbiology and Genetics, University of Salamanca Salamanca, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Hermosa
authors.affiliation: Abiotic Stress Department, Institute of Natural Resources and Agrobiology of Salamanca - Consejo Superior de Investigaciones Científicas Salamanca, Spain.
authors.forename: Rubén
authors.initials: R
authors.lastname: Vicente
authors.affiliation: Spanish-Portuguese Institute for Agricultural Research (CIALE), Department of Microbiology and Genetics, University of Salamanca Salamanca, Spain.
authors.forename: Fabio A
authors.initials: FA
authors.lastname: Gómez-Acosta
authors.affiliation: Abiotic Stress Department, Institute of Natural Resources and Agrobiology of Salamanca - Consejo Superior de Investigaciones Científicas Salamanca, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Morcuende
authors.affiliation: Spanish-Portuguese Institute for Agricultural Research (CIALE), Department of Microbiology and Genetics, University of Salamanca Salamanca, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Monte
authors.affiliation: Spanish-Portuguese Institute for Agricultural Research (CIALE), Department of Microbiology and Genetics, University of SalamancaSalamanca, Spain; Embrapa EnvironmentJaguariúna, Brazil.
authors.forename: Wagner
authors.initials: W
authors.lastname: Bettiol
keywords: abiotic stress; growth promotion; nitrogen fertilizer; phytohormone regulation; saline