title: Marine isolates of Trichoderma spp. as potential halotolerant agents of biological control for arid-zone agriculture.
abstract: The scarcity of fresh water in the Mediterranean region necessitates the search for halotolerant agents of biological control of plant diseases that can be applied in arid-zone agriculture irrigated with saline water. Among 29 Trichoderma strains previously isolated from Mediterranean Psammocinia sp. sponges, the greatest number of isolates belong to the Trichoderma longibrachiatum-Hypocrea orientalis species pair (9), H. atroviridis/T. atroviride (9), and T. harzianum species complex (7), all of which are known for high mycoparasitic potential. In addition, one isolate of T. asperelloides and two putative new species, Trichoderma sp. O.Y. 14707 and O.Y. 2407, from Longibrachiatum and Strictipilosa clades, respectively, have been identified. In vitro salinity assays showed that the ability to tolerate increasing osmotic pressure (halotolerance) is a strain- or clade-specific property rather than a feature of a species. Only a few isolates were found to be sensitive to increased salinity, while others either were halotolerant or even demonstrated improved growth in increasingly saline conditions. In vitro antibiosis assays revealed strong antagonistic activity toward phytopathogens due to the production of both soluble and volatile metabolites. Two marine-derived Trichoderma isolates, identified as T. atroviride and T. asperelloides, respectively, effectively reduced Rhizoctonia solani damping-off disease on beans and also induced defense responses in cucumber seedlings against Pseudomonas syringae pv. lachrimans. This is the first inclusive evaluation of marine fungi as potential biocontrol agents.
authors.affiliation: Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
authors.forename: Inbal
authors.initials: I
authors.lastname: Gal-Hemed
authors.forename: Lea
authors.initials: L
authors.lastname: Atanasova
authors.forename: Monika
authors.initials: M
authors.lastname: Komon-Zelazowska
authors.forename: Irina S
authors.initials: IS
authors.lastname: Druzhinina
authors.forename: Ada
authors.initials: A
authors.lastname: Viterbo
authors.forename: Oded
authors.initials: O
authors.lastname: Yarden
mesh_terms: D000383:Agriculture; D000818:Animals; D000898:Antibiosis / Q000235:genetics; D059001:Aquatic Organisms / Q000382:microbiology*; D061046:Biological Control Agents; D018556:Crops, Agricultural / Q000382:microbiology; D008522:Mediterranean Sea; D008969:Molecular Sequence Data; D009997:Osmotic Pressure / Q000502:physiology; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology / Q000628:therapy*; D018517:Plant Roots / Q000382:microbiology; D011161:Porifera / Q000382:microbiology; D054712:Salinity; D055051:Salt-Tolerant Plants; D014242:Trichoderma / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology
chemical_list: D061046:Biological Control Agents