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Salicylic acid modulates ozone‐induced hypersensitive cell death in tobacco plants
Author(s) -
Pasqualini Stefania,
Della Torre Guido,
Ferranti Francesco,
Ederli Luisa,
Piccioni Claudia,
Reale Lara,
Antonielli Marisa
Publication year - 2002
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 - 10.1034/j.1399-3054.2002.1150205.x
Subject(s) - fumigation , salicylic acid , cultivar , ozone , horticulture , chemistry , apoplast , botany , biology , biochemistry , cell wall , organic chemistry
Ozone‐tolerant Bel B and ozone‐sensitive Bel W3 tobacco cultivars were subjected to acute ozone fumigation (200 p.p.b. for 3 h) and the subcellular localization of H 2 O 2 was then studied. H 2 O 2 accumulated on the cell walls and plasma membrane of both cultivars but the accumulation pattern differed greatly. H 2 O 2 production was high in both cultivars immediately after fumigation, but, in the tolerant Bel B cultivar, after 7 h was only detected in some spongy cells adjacent to epidermal cells. Instead, in the sensitive Bel W3 cultivar, accumulation was still abundant in the cell walls of palisade, spongy and epidermal cells at this time. Significant changes in apoplastic ascorbate pool were noted in both cultivars in the first hours after fumigation. As the reduced ascorbate content remained unchanged, the marked increase in total ascorbate must have originated from the striking increase in dehydroascorbate, particularly in the ozone‐sensitive Bel W3. Exposure of plants to ozone resulted in a marked transient increase in both free and conjugated salicylic acid (SA) as well as an increase in the activity of benzoic acid 2‐hydroxylase which catalyses SA biosynthesis. SA induction differed greatly in the two cultivars, in that: (1) SA accumulation was far greater in the ozone‐sensitive Bel W3 cv. and (2) the maximum SA peak was delayed in Bel W3 and observed only 7 h after fumigation ended. These results suggest that a high SA content, as documented in the ozone‐sensitive Bel W3 cultivar, could trigger the production of ROS with subsequent SA‐mediated cell‐death.