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Kinetics of drought‐induced pathogenesis‐related proteins and its physiological significance in white clover leaves
Author(s) -
Lee BokRye,
Jung WooJin,
Lee ByungHyun,
Avice JeanChristophe,
Ourry Alain,
Kim TaeHwan
Publication year - 2008
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2007.01014.x
Subject(s) - chitinase , glucanase , proline , cellulase , enzyme assay , chemistry , pathogenesis related protein , enzyme , botany , biology , zoology , biochemistry , amino acid , gene expression , gene
To investigate the responses of pathogenesis‐related (PR) proteins to the intensity of drought stress and their physiological significance in white clover ( Trifolium repens L.), the change of enzyme activity and its relationship with some physiological parameters were assessed for 28 days under well‐watered (control) and water‐deficit conditions. Water‐deficit treatment gradually decreased leaf water potential (Ψ w ) to −2.33 MPa at day 28. Dry matter significantly decreased from 21 days of water‐deficit treatment, while proline and ammonia concentration increased within 7 days. The increase in PR‐protein activity was closely related with the decrease in Ψ w . The β‐1,3‐glucanase (EC 3.2.1.39) activity in water‐deficit leaves rapidly increased for the first 14 days (Ψ w ≥ −1.67) and then slightly decreased, while the chitinase (EC 3.2.1.14) and cellulase (EC 3.2.1.4) activity continued to increase throughout the experimental period. The enhanced activation of β‐1,3‐glucanase, chitinase and cellulase for the period of days 0–14 was significantly ( P ≤ 0.01) related to the increase of proline and ammonia concentrations. The results indicate that the enhanced activity of β‐1,3‐glucanase, cellulase and chitinase for the early period might be an act of transient tolerance to drought stress, but the activation of these enzymes during terminal stress might be a drought‐stress‐induced injurious symptom.