title: Arbuscular mycorrhizal symbiosis influences strigolactone production under salinity and alleviates salt stress in lettuce plants.
abstract: Arbuscular mycorrhizal (AM) symbiosis can alleviate salt stress in plants. However the intimate mechanisms involved, as well as the effect of salinity on the production of signalling molecules associated to the host plant-AM fungus interaction remains largely unknown. In the present work, we have investigated the effects of salinity on lettuce plant performance and production of strigolactones, and assessed its influence on mycorrhizal root colonization. Three different salt concentrations were applied to mycorrhizal and non-mycorrhizal plants, and their effects, over time, analyzed. Plant biomass, stomatal conductance, efficiency of photosystem II, as well as ABA content and strigolactone production were assessed. The expression of ABA biosynthesis genes was also analyzed. AM plants showed improved growth rates and a better performance of physiological parameters such as stomatal conductance and efficiency of photosystem II than non-mycorrhizal plants under salt stress since very early stages - 3 weeks - of plant colonization. Moreover, ABA levels were lower in those plants, suggesting that they were less stressed than non-colonized plants. On the other hand, we show that both AM symbiosis and salinity influence strigolactone production, although in a different way in AM and non-AM plants. The results suggest that AM symbiosis alleviates salt stress by altering the hormonal profiles and affecting plant physiology in the host plant. Moreover, a correlation between strigolactone production, ABA content, AM root colonization and salinity level is shown. We propose here that under these unfavourable conditions, plants increase strigolactone production in order to promote symbiosis establishment to cope with salt stress.
authors.affiliation: Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas (EEZ-CSIC), Profesor Albareda 1, 18008 Granada, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Aroca
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Ruiz-Lozano
authors.forename: Angel María
authors.initials: AM
authors.lastname: Zamarreño
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Paz
authors.forename: José María
authors.initials: JM
authors.lastname: García-Mina
authors.forename: María José
authors.initials: MJ
authors.lastname: Pozo
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: López-Ráez
mesh_terms: D000040:Abscisic Acid / Q000235:genetics / Q000378:metabolism*; D018533:Biomass; D018506:Gene Expression Regulation, Plant; D018525:Germination; D055137:Glomeromycota / Q000254:growth & development / Q000502:physiology*; D007783:Lactones / Q000378:metabolism*; D018545:Lactuca / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology* / Q000502:physiology; D038821:Mycorrhizae / Q000254:growth & development / Q000502:physiology*; D045332:Photosystem II Protein Complex / Q000502:physiology; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology / Q000502:physiology; D018526:Plant Transpiration; D054712:Salinity; D012639:Seeds / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological; D013559:Symbiosis; D013997:Time Factors
chemical_list: D007783:Lactones; D045332:Photosystem II Protein Complex; D012965:Sodium Chloride; D000040:Abscisic Acid