title: Native plant growth promoting bacteria Bacillus thuringiensis and mixed or individual mycorrhizal species improved drought tolerance and oxidative metabolism in Lavandula dentata plants.
abstract: This study evaluates the responses of Lavandula dentata under drought conditions to the inoculation with single autochthonous arbuscular mycorrhizal (AM) fungus (five fungal strains) or with their mixture and the effects of these inocula with a native Bacillus thuringiensis (endophytic bacteria). These microorganisms were drought tolerant and in general, increased plant growth and nutrition. Particularly, the AM fungal mixture and B. thuringiensis maximized plant biomass and compensated drought stress as values of antioxidant activities [superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase APX)] shown. The AMF-bacteria interactions highly reduced the plant oxidative damage of lipids [malondialdehyde (MDA)] and increased the mycorrhizal development (mainly arbuscular formation representative of symbiotic functionality). These microbial interactions explain the highest potential of dually inoculated plants to tolerate drought stress. B. thuringiensis "in vitro" under osmotic stress does not reduce its PGPB (plant growth promoting bacteria) abilities as indole acetic acid (IAA) and ACC deaminase production and phosphate solubilization indicating its capacity to improve plant growth under stress conditions. Each one of the autochthonous fungal strains maintained their particular interaction with B. thuringiensis reflecting the diversity, intrinsic abilities and inherent compatibility of these microorganisms. In general, autochthonous AM fungal species and particularly their mixture with B. thuringiensis demonstrated their potential for protecting plants against drought and helping plants to thrive in semiarid ecosystems.
authors.affiliation: Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Prof. Albareda 1, 18008 Granada, Spain. Electronic address: elisabeth.armada@eez.csic.es.
authors.forename: E
authors.initials: E
authors.lastname: Armada
authors.affiliation: Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad San Pablo CEU, 28668 Boadilla del Monte, Madrid, Spain. Electronic address: a.probanza@ceu.es.
authors.forename: A
authors.initials: A
authors.lastname: Probanza
authors.affiliation: CSIC-Centro de Edafología y Biología Aplicada del Segura, Department of Soil and Water Conservation, P.O. Box 164, Campus de Espinardo, 30100 Murcia, Spain. Electronic address: aroldan@cebas.csic.es.
authors.forename: A
authors.initials: A
authors.lastname: Roldán
authors.affiliation: Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, Prof. Albareda 1, 18008 Granada, Spain. Electronic address: rosario.azcon@eez.csic.es.
authors.forename: R
authors.initials: R
authors.lastname: Azcón
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001413:Bacillus thuringiensis / Q000502:physiology*; D018533:Biomass; D003681:Dehydration; D055864:Droughts; D027523:Lavandula / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology* / Q000648:ultrastructure; D038821:Mycorrhizae / Q000254:growth & development / Q000502:physiology*; D018384:Oxidative Stress; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology / Q000648:ultrastructure; D018520:Plant Shoots / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology / Q000648:ultrastructure; D013559:Symbiosis
chemical_list: D000975:Antioxidants
keywords: Autochthonous bacterial strain; Autochthonous mycorrhizal fungi; Enzymatic antioxidants; Oxidative damage; Water stress