Salicylic acid (SA) is well known hormonal molecule involved in cell death regulation. In response to a broad range of environmental factors (e.g., high light, UV, pathogens attack), plants accumulate SA, which participates in cell death induction and spread in some foliar cells.
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Salicylic acid (SA) is well known hormonal molecule involved in cell death regulation. In response to a broad range of environmental factors (e.g., high light, UV, pathogens attack), plants accumulate SA, which participates in cell death induction and spread in some foliar cells. LESION SIMULATING DISEASE 1 (LSD1) is one of the best-known cell death regulators in
Arabidopsis thaliana. The
lsd1 mutant, lacking functional LSD1 protein, accumulates SA and is conditionally susceptible to many biotic and abiotic stresses. In order to get more insight into the role of LSD1-dependent regulation of SA accumulation during cell death, we crossed the
lsd1 with the
sid2 mutant, caring mutation in
ISOCHORISMATE SYNTHASE 1(ICS1) gene and having deregulated SA synthesis, and with plants expressing the bacterial
nahG gene and thus decomposing SA to catechol. In response to UV A+B irradiation, the
lsd1 mutant exhibited clear cell death phenotype, which was reversed in
lsd1/sid2 and
lsd1/
NahG plants. The expression of
PR-genes and the H
2O
2 content in UV-treated
lsd1 were significantly higher when compared with the wild type. In contrast,
lsd1/sid2 and
lsd1/
NahG plants demonstrated comparability with the wild-type level of
PR-genes expression and H
2O
2. Our results demonstrate that SA accumulation is crucial for triggering cell death in
lsd1, while the reduction of excessive SA accumulation may lead to a greater tolerance toward abiotic stress.
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