Premium
The phytohormone auxin is a component of the regulatory system that controls UV‐mediated accumulation of flavonoids and UV‐induced morphogenesis
Author(s) -
Hectors Kathleen,
van Oevelen Sandra,
Guisez Yves,
Prinsen Els,
Jansen Marcel A. K.
Publication year - 2012
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 - 10.1111/j.1399-3054.2012.01590.x
Subject(s) - auxin , mutant , morphogenesis , flavonoid , arabidopsis thaliana , biology , biochemistry , arabidopsis , acclimatization , botany , flavonoid biosynthesis , chemistry , gene , transcriptome , gene expression , antioxidant
In plants, ultraviolet (UV)‐B acclimation is a complex, dynamic process that plays an essential role in preventing UV‐B damage to targets such as DNA and the photosynthetic machinery. In this study we tested the hypothesis that the phytohormone auxin is a component of the regulatory system that controls both UV‐mediated accumulation of flavonoids and UV‐induced morphogenesis. We found that the leaf area of Arabidopsis thaliana Col‐0 plants raised under a low dose of UV radiation (0.56 kJ m −2 daily dose) was, on average, decreased by 23% relative to plants raised in the absence of UV‐B, and this was accompanied by a decrease ( P = 0.063) in free auxin in young leaf tissues. Compared to Col‐0, both the auxin influx mutant axr4‐1 and the auxin biosynthesis mutant nit1‐3 displayed significantly stronger morphogenic responses, i.e. relative decreases in leaf area were greater for these two mutants. UV exposure also induced accumulation of flavonoids. In Col‐0, increases in the concentrations of specific kaempferol derivatives ranged from 2.1‐ to 19‐fold. Thus, UV induces complex changes in flavonoid–glycosylation patterns. Compared to Col‐0, three auxin mutants displayed significantly different flavonoid profiles. Thus, based on mutant analysis, it is concluded that the phytohormone auxin plays a role in UV acclimation by regulating flavonoid concentration, flavonoid–glycosylation pattern and by controlling UV‐induced morphogenic responses.