Format: ORAL

Romano-Rodrguez Elena1, Flores-Duarte N.J1, Mateos-Naranjo Enrique1, Navarro-Torre Salvadora2, Rodrguez-Llorente Ignacio D.2, Pajuelo Elosa2, Redondo-Gmez Susana1.

1.Department of Plant Biology and Ecology, Faculty of Biology, University of Seville, Apartado 1095, 41080, Seville, Spain. 2.Department of Microbiology, Faculty of Pharmacy, University of Seville, C/ Profesor García González 2, 41012, Seville, Spain.

In recent years, several efforts have been made to enhance the salt-tolerance of plants, as salinity stress is one of the major abiotic stresses threatening crop production in arid and semi-arid regions. Also, soil salinization is expected to increase due to climate change and increased irrigation practices. Recent research has shown that bioaugmentation of crops with halotolerant bacteria isolated from halophytic plants can alleviate salt stress and promote plant growth. Halocnemum strobilaceum is a widespread hyperhalophyte desert plant known for its antioxidant, antimicrobial, insecticidal and phytoremediation properties. However, it is critically endangered in Spain. Whereas most of the studies focus on rhizospheric bacteria, little is known about how endophytes helps halophytes to cope with salt stress. In this work we study the diversity of endophytic bacteria of Halocnemum strobilaceum from arid areas of Murcia and Almeria, Spain. In total, 79 endophytic bacterial strains were isolated from the aerial parts of this halophytic plant on tryptic soy Agar supplemented with 0.5 M NaCl to ensurance their salt tolerance. They show in vitro plant growth promoting (PGP) properties as phosphate solubilization, siderophore production, auxin IAA production, biofilm formation, and enzimatic activities as protease or cellulase. We also carried out 16S rRNA gene sequencing and found several isolates could be new potential species of Halomonas and Kushneria, a relatively novel and small genera. We selected three best strains based on their PGP properties and set up a greenhouse trial with Medicago sativa under 100mM NaCl salinity stress to test the consortia capacity in mitigating salt stress.