O-acetylserine (thiol) lyase activity in Phragmites and Typha plants under cadmium and NaCl stress conditions and the involvement of ABA in the stress response.
The roles of O-acetylserine (thiol) lyase (OASTL, EC 4.2.99.8) and abscisic (ABA) acid in stress responses to NaCl and cadmium treatments were investigated in Typha latifolia L. and Phragmites australis (Cav.) Trin. ex Steudel plants. OASTL activity increased under stress (25-300 microM Cd, 100mM NaCl, 1 microM ABA) in both Typha and Phragmites mainly in roots, contributing substantially to satisfy the higher demand of cysteine for adaptation and protection. The earliest significant responses in intact roots were recorded after 12-24 h of Cd treatments, but different levels of stimulation were also observed after 3 and 7 days of exposure. The OASTL activity responses of Phragmites to salinity (100mM NaCl) were higher than those of Typha. Cysteine synthesis in Typha is much higher than in Phragmites, which supports the efficiency of the thiol-metabolism-based protection shown in Typha. Exogenous ABA increased OASTL activity in both species. Cd treatments led to increased ABA levels in roots. Phragmites showed higher ABA levels compared to Typha. The increase of ABA content indicates the involvement of this phytohormone in early stress responses, while the stimulation of OASTL following the ABA application suggests that ABA has a role in an OASTL activation pathway.
Fediuc
Erika
E
Biostress Research Laboratory, J. Blaustein Institute for Desert Researches, Ben Gurion University of the Negev, Sede Boqer Campus, 84990 Israel.
Lips
S Herman
SH
Erdei
László
L
D000040:Abscisic Acid / Q000502:physiology*; D002104:Cadmium / Q000633:toxicity*; D019757:Carbon-Oxygen Lyases / Q000378:metabolism*; D004789:Enzyme Activation; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology; D006109:Poaceae / Q000187:drug effects / Q000201:enzymology*; D012965:Sodium Chloride / Q000633:toxicity*; D013045:Species Specificity; D032401:Typhaceae / Q000187:drug effects / Q000201:enzymology*
D002104:Cadmium; D012965:Sodium Chloride; D000040:Abscisic Acid; C018725:O-acetylhomoserine (thiol)-lyase; D019757:Carbon-Oxygen Lyases