title: Defense related phytohormones regulation in arbuscular mycorrhizal symbioses depends on the partner genotypes.
abstract: Arbuscular mycorrhizal (AM) symbioses are mutualistic associations between soil fungi and most vascular plants. Modulation of the hormonal and transcriptional profiles, including changes related to defense signalling, has been reported in many host plants during AM symbioses. These changes have been often related to the improved stress tolerance common in mycorrhizal plants. However, results on the alterations in phytohormones content and their role on the symbiosis are controversial. Here, an integrative analysis of the response of phylogenetically diverse plants (i.e., tomato, soybean, and maize) to two mycorrhizal fungi -Funneliformis mosseae and Rhizophagus irregularis- was performed. The analysis of the defense-related hormones salicylic acid, abscisic acid, and jasmonates, and the expression of marker genes of the pathways they regulate, revealed significant changes in the roots of mycorrhizal plants. These changes depended on both the plant and the AM fungus (AMF) involved. However, general trends can be identified: roots associated with the most effective colonizer R. irregularis showed fewer changes in these defense-related traits, while the colonization by F. mosseae led to significant modifications in all plants tested. The up-regulation of the jasmonate pathway by F. mosseae was found to be highly conserved among the different plant species, suggesting an important role of jasmonates during this AM interaction. Our study evidences a strong influence of the AMF genotype on the modulation of host defense signalling, and offers hints on the role of these changes in the symbiosis.
authors.affiliation: Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (CSIC), Granada, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Fernández
authors.forename: M
authors.initials: M
authors.lastname: Merlos
authors.forename: J A
authors.initials: JA
authors.lastname: López-Ráez
authors.forename: A
authors.initials: A
authors.lastname: Martínez-Medina
authors.forename: N
authors.initials: N
authors.lastname: Ferrol
authors.forename: C
authors.initials: C
authors.lastname: Azcón
authors.forename: P
authors.initials: P
authors.lastname: Bonfante
authors.forename: V
authors.initials: V
authors.lastname: Flors
authors.forename: M J
authors.initials: MJ
authors.lastname: Pozo
mesh_terms: D000040:Abscisic Acid / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D003517:Cyclopentanes / Q000032:analysis; D005838:Genotype; D055137:Glomeromycota / Q000235:genetics / Q000502:physiology*; D018551:Solanum lycopersicum / Q000378:metabolism*; D038821:Mycorrhizae / Q000378:metabolism; D054883:Oxylipins / Q000032:analysis; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism; D020156:Salicylic Acid / Q000032:analysis; D013025:Glycine max / Q000378:metabolism*; D013559:Symbiosis; D053719:Tandem Mass Spectrometry; D015854:Up-Regulation; D003313:Zea mays / Q000378:metabolism*
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; C011006:jasmonic acid; D000040:Abscisic Acid; D020156:Salicylic Acid