Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Israel → Isolation and characterization of genes related to salt tolerance from Dead Sea fungus Eurotium herbariorum

Haïfa University (2005)

Isolation and characterization of genes related to salt tolerance from Dead Sea fungus Eurotium herbariorum

Yen, Chin

Titre : Isolation and characterization of genes related to salt tolerance from Dead Sea fungus Eurotium herbariorum

Auteur : Yen, Chin

Etablissement de soutenance : Haïfa University

Grade : Doctor of Philosophy (PhD) 2005

Résumé partiel
The Dead Sea, located in the Syrian­Arfican ritf valley between Israel and Jordan, is the lowest continental depression on earth, with its surface standing at­419 m mean sea level. The Dead Sea is oneofthe most saline lakes on earth (with a salinity of about 340 g/1). The lake differs from other hypersaline lakes in the unique ionic composition of its waters, with concentrations of divalent cations (Mg, 40.7 g/1; Ca, 17 g/1) exceeding those of monovalent cations (Na, 39.2 g/1; K, 7.0 g/1). The major anions are Cl (212 g/1) and Br )5 g/1) (Buchalo et al., 1998). The low­water activity (<0.669) makes the Dead Sea a hostile environment to most forms of life. A variety of microorganisms exists within the Dead Sea water including red halophilic archaea, unicellular green algae Dunaliellaparva Lerche), different types of bacteria, and possibly even protozoa. The alga is eitherthe main or only primary producer inthe Dead Sea. The prokaryotic communityofthe Dead Sea is dominated by extremely halophilic archaeaofthe family Halobacteriaceae considered the only decomposers in theDead Sea. The firstevidenceofthe occurrence offilamentous fungi was found recently by Buchalo et al. (1998). A variety of fungi was isolated from the Dead Sea, both from surface water at the shore and inthe center ofthe lake and rfom deep water samples. E herbariorum, A. versicolor, and C. cladosporioides are among the indigenous filamentous fungi in the Dead Sea water. Eurotiumherbariorum is the most common species isolated from Dead Sea water. The fungi living in high­saline environments develop two major strategies for counteracting salt stress­ intracellular ion toxicity and osmotic stress : osmolyte synthesis and accumulation of polyols, mainly glycerol, are major osmoregulatory strategies of fungal salttolerance; and cationtransport is used for an effectiveexclusionofNa+. In this thesis, Eurotium herbariorum was used as. the research material. Some genes related to glycerol synthesis, osmoregulation, and cation transportation were isolated and characterized to shed light on the mechanismofsalt tolerance.

Présentation -> http://digitool.haifa.ac.il/R/VPDHY...

Version intégrale ( 0,58 Mb)

Page publiée le 26 novembre 2018