title: Differential effects of Pseudomonas mendocina and Glomus intraradices on lettuce plants physiological response and aquaporin PIP2 gene expression under elevated atmospheric CO2 and drought.
abstract: Arbuscular mycorrhizal (AM) symbiosis and plant-growth-promoting rhizobacterium (PGPR) can alleviate the effects of water stress in plants, but it is unknown whether these benefits can be maintained at elevated CO2. Therefore, we carried out a study where seedlings of Lactuca sativa were inoculated with the AM fungus (AMF) Glomus intraradices N.C. Schenk & G.S. Sm. or the PGPR Pseudomonas mendocina Palleroni and subjected to two levels of watering and two levels of atmospheric CO2 to ascertain their effects on plant physiological parameters and gene expression of one PIP aquaporin in roots. The inoculation with PGPR produced the greatest growth in lettuce plants under all assayed treatments as well as the highest foliar potassium concentration and leaf relative water content under elevated [CO2] and drought. However, under such conditions, the PIP2 gene expression remained almost unchanged. G. intraradices increased significantly the AMF colonization, foliar phosphorus concentration and leaf relative water content in plants grown under drought and elevated [CO2]. Under drought and elevated [CO2], the plants inoculated with G. intraradices showed enhanced expression of the PIP2 gene as compared to P. mendocina or control plants. Our results suggest that both microbial inoculation treatments could help to alleviate drought at elevated [CO2]. However, the PIP2 gene expression was increased only by the AMF but not by the PGPR under these conditions.
authors.affiliation: Department of Soil and Water Conservation, CSIC-Centro de Edafología y Biología Aplicada del Segura, P.O. Box 164, Campus de Espinardo, 30100, Murcia, Spain. mmalguacil@cebas.csic.es
authors.forename: Maria Del Mar
authors.initials: Mdel M
authors.lastname: Alguacil
authors.forename: Josef
authors.initials: J
authors.lastname: Kohler
authors.forename: Fuensanta
authors.initials: F
authors.lastname: Caravaca
authors.forename: Antonio
authors.initials: A
authors.lastname: Roldán
mesh_terms: D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D018533:Biomass; D002245:Carbon Dioxide / Q000378:metabolism*; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018545:Lactuca / Q000235:genetics / Q000382:microbiology* / Q000502:physiology; D038821:Mycorrhizae / Q000254:growth & development*; D010758:Phosphorus / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D018526:Plant Transpiration; D044203:Pseudomonas mendocina / Q000254:growth & development*; D013559:Symbiosis; D014867:Water / Q000378:metabolism
chemical_list: D020346:Aquaporins; D010940:Plant Proteins; D014867:Water; D002245:Carbon Dioxide; D010758:Phosphorus