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MASSIVE ACCUMULATION OF PHYTOENE INDUCED BY NORFLURAZON IN DUNALIELLA BARDAWIL (CHLOROPHYCEAE) PREVENTS RECOVERY FROM PHOTOINHIBITION 1
Author(s) -
BenAmotz Ami,
Gressel Jonathan,
Avron Mordhay
Publication year - 1987
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.0022-3646.1987.00176.x
Subject(s) - phytoene , dunaliella , dunaliella salina , biology , photoinhibition , phytoene desaturase , chlorophyceae , carotene , carotenoid , botany , chlorophyta , xanthophyll , biochemistry , algae , photosynthesis , biosynthesis , gene , lycopene , photosystem ii
The effects of nanomolar to micromolar concentrations of the herbicide norflurazon were studied in Dunaliella bardawil Ben‐Amotz et Avron, a β‐carotene‐accumulating halotolerant alga. The large amount of β‐carotene which Dunaliella bardawil can contain, around 8% of the algal dry weight, is reduced to 0.2% by treatment with 100 nm norflurazon. Simultaneously, phytoene is accumulated to a similar level of about 8%. The gradual increase in phytoene content, in response to increasing norflurazon concentrations, corresponds to the decrease in β‐carotene, with no evident change in other isoprenoid intermediates. Carotene‐rich Dunaliella bardawil is substantially resistant to high‐intensity photoinhibition. This resistance is lost in cells grown to contain low β‐carotene and in the norflurazon‐treated phytoene‐rich cells. These observations are in agreement with the hypothesis that the accumulated β‐carotene in Dunaliella bardawil protects the cells against injury by excessive irradiation.