Euphorbia helioscopia a Putative Plant Reservoir of Pathogenic Curtobacterium flaccumfaciens.

The endophyte EHF3 strain was isolated in Algeria from an Euphorbia helioscopia plant growing in a fallow field. The strain was characterized by biochemical and physiological tests and assayed for the production of secondary metabolites involved in biocontrol, for plant growth promotion ability and for pathogenicity. The strain was identified by BIOLOG test as Curtobacterium flaccumfaciens. Biochemical and physiological characterization revealed that the strain was able to secrete protease, caseinase and amylase enzymes, to grow up to 37 °C and at pH values 5 to 9. C. flaccumfaciens EHF3 strain was incapable of solubilizing phosphorus and to produce IAA, HCN siderophores and phenazine compounds. The strain showed a moderate swimming and swarming motility and produced biofilm. EHF3 strain was positive at the hypersensitivity test on tobacco plants and induced symptoms on three varieties of bean resembling to those of the bacterial wilt disease induced by C. flaccumfaciens pv. flaccumfaciens. The preliminary data reported in this study, regarding the detection of a pathogenic C. flaccumfaciens strain, as endophyte of a E. helioscopia plant, highlight the role of non-host plants as reservoir of this bacterial pathogen.

Endophytic fungi associated with roots of date palm (Phoenix dactylifera) in coastal dunes / Hongos endófitos asociados con raíces de palmera datilera (Phoenix dactylifera) en dunas costeras

Background. Symbiotic interactions with fungal endophytes are argued to be responsible for the tolerance of plants to some stresses and for their adaptation to natural conditions. Aims. In this study we aimed to examine the endophytic fungal diversity associated with roots of date palms growing in coastal dune systems, and to screen this collection of endophytes for potential use as biocontrol agents, for antagonistic activity and mycoparasitism, and as producers of antifungal compounds with potential efficacy against root diseases of date palm. Methods. Roots of nine individual date palms growing in three coastal locations in the South-East of Spain (Guardamar, El Carabassí, and San Juan) were selected to isolate endophytic fungi. Isolates were identified on the basis of morphological and/or molecular characters. Results. Five hundred and fifty two endophytic fungi were isolated and assigned to thirty morphological taxa or molecular operational taxonomic units. Most isolates belonged to Ascomycota, and the dominant order was Hypocreales. Fusarium and Clonostachys were the most frequently isolated genera and were present at all sampling sites. Comparisons of the endophytic diversity with previous studies, and their importance in the management of the date palm crops are discussed. Conclusions. This is the first study on the diversity of endophytic fungi associated with roots of date palm. The isolates obtained might constitute a source of biological control agents and biofertilizers for use in crops of this plant (AU)

Antecedentes. Se ha propuesto que la simbiosis con hongos endófitos puede ser responsable de la tolerancia de las plantas a algunas situaciones de estrés ambiental y de su adaptación a las condiciones naturales. Objetivos. Este estudio tiene como objetivo analizar la diversidad de hongos endófitos asociados con las raíces de palmeras datileras que crecen en sistemas de dunas costeras. La finalidad es la evaluación de un grupo de cepas fúngicas para su uso como agentes de control biológico por su actividad antagónica o micoparasitaria, o como productores de compuestos antifúngicos con potencial aplicación frente a enfermedades radiculares de la palmera datilera. Métodos. Se muestrearon raíces de 9 palmeras que crecían en 3 localidades costeras en el Sudeste de España (Guardamar, El Carabassí y San Juan), y se aislaron sus hongos endófitos asociados. Las cepas se identificaron mediante el estudio de caracteres morfológicos y/o moleculares. Resultados. Se aislaron 552 hongos endófitos, que se clasificaron en 30 taxones morfológicos o unidades taxonómicas operativas moleculares. La mayoría de las cepas pertenecen a la división Ascomycota; el orden dominante fue Hypocreales. Los géneros aislados con más frecuencia fueron Fusarium y Clonostachys, que estuvieron presentes en todos los sitios de muestreo. Nuestros resultados de diversidad hongos endófitos se comparan con los de otros estudios previos, y se discute su importancia para el tratamiento de cultivos de palmera datilera. Conclusiones. Este es el primer estudio sobre la diversidad fúngica endofíticamente asociada con raíces de palmera datilera. Las cepas obtenidas son una fuente potencial de agentes de control biológico o biofertilizantes para la aplicación en cultivos de esta planta (AU)

Endophytic fungi associated with roots of date palm (Phoenix dactylifera) in coastal dunes.

BACKGROUND: Symbiotic interactions with fungal endophytes are argued to be responsible for the tolerance of plants to some stresses and for their adaptation to natural conditions. AIMS: In this study we aimed to examine the endophytic fungal diversity associated with roots of date palms growing in coastal dune systems, and to screen this collection of endophytes for potential use as biocontrol agents, for antagonistic activity and mycoparasitism, and as producers of antifungal compounds with potential efficacy against root diseases of date palm. METHODS: Roots of nine individual date palms growing in three coastal locations in the South-East of Spain (Guardamar, El Carabassí, and San Juan) were selected to isolate endophytic fungi. Isolates were identified on the basis of morphological and/or molecular characters. RESULTS: Five hundred and fifty two endophytic fungi were isolated and assigned to thirty morphological taxa or molecular operational taxonomic units. Most isolates belonged to Ascomycota, and the dominant order was Hypocreales. Fusarium and Clonostachys were the most frequently isolated genera and were present at all sampling sites. Comparisons of the endophytic diversity with previous studies, and their importance in the management of the date palm crops are discussed. CONCLUSIONS: This is the first study on the diversity of endophytic fungi associated with roots of date palm. The isolates obtained might constitute a source of biological control agents and biofertilizers for use in crops of this plant.