Effects of low temperature on stress ethylene biosynthesis in soybean hypersensitively responding to tobacco necrosis virus
1992
Pennazio, S. (Consiglio Nazionale delle Ricerche, Turin (Italy). Ist. di Fitovirologia Applicata) | Roggero, P.
The hypersensitive reaction to tobacco necrosis virus in soybean plants grown at 10 degrees C, when compared with that of non-chilled plants (see Pennazio and Roggero, 1990 a, b), was characterized by (1) delayed appearance of necrosis local lesions, (2) smaller size of lesions, and (3) viability of the inoculated leaves. The content of virus antigen accumulated in the lesions was, however, unchanged. Chilling did not affect the biosynthetic pathway of stress ethylene, but did affect the kinetics of ethylene release. No burst of ethylene, followed by a rapid decline, was found, but ethylene production gradually increased up to moderate values, which were maintained for several days. This finding may explain the abolition, at 10 degrees C, of the leaf fall occurring in non-chilled conditions. Free ACC accumulation and stress ethylene release occurred 24 h before appearance of visible necrotic pin point lesions. EFE activity was, however, stimulated only in later stages of pathogenesis. Stress ethylene release did not affect virus multiplication, nor was it considered a cause of the observed restriction of virus spread, which may have been an effect of the low temperature on the cell-to-cell virus transport mechanism
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