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Light filtering by epidermal flavonoids during the resistant response of cotton to Xanthomonas protects leaf tissue from light-dependent phytoalexin toxicity
- Source :
- Phytochemistry. 69:2320-2328
- Publication Year :
- 2008
- Publisher :
- Elsevier BV, 2008.
-
Abstract
- 2,7-Dihydroxycadalene and lacinilene C, sesquiterpenoid phytoalexins that accumulate at infection sites during the hypersensitive resistant response of cotton foliage to Xanthomonas campestris pv. malvacearum, have light-dependent toxicity toward host cells, as well as toward the bacterial pathogen. Adaxial epidermal cells surrounding and sometimes covering infection sites turn red. The red cells exhibited 3-4-fold higher absorption at the photoactivating wavelengths of sunlight than nearby colorless epidermal cells. Red epidermal cells protected underlying palisade mesophyll cells from the toxic effects of 2,7-dihydroxycadalene plus sunlight, indicating a role for epidermal pigments in protecting living cells that surround infection sites from toxic effects of the plant's own phytoalexins. A semi-quantitative survey of UV-absorbing substances extracted from epidermal strips from inoculated and mock-inoculated cotyledons indicated that the principal increase in capacity to absorb the photoactivating wavelengths was due to a red anthocyanin and a yellow flavonol, which were identified as cyanidin-3-O-beta-glucoside and quercetin-3-O-beta-glucoside, respectively.
- Subjects :
- Light
Flavonoid
Plant Science
Horticulture
Biology
Biochemistry
Palisade cell
Microbiology
chemistry.chemical_compound
Xanthomonas
Phytoalexins
Molecular Biology
Plant Diseases
Flavonoids
chemistry.chemical_classification
Gossypium
integumentary system
Epidermis (botany)
Pigmentation
Terpenes
Phytoalexin
General Medicine
biology.organism_classification
Xanthomonas campestris
Plant Leaves
chemistry
Spectrophotometry
Anthocyanin
Sunlight
Chrysanthemin
Sesquiterpenes
Subjects
Details
- ISSN :
- 00319422
- Volume :
- 69
- Database :
- OpenAIRE
- Journal :
- Phytochemistry
- Accession number :
- edsair.doi.dedup.....a6736212d8ebf7404764d3b6aec9af8f