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Dissecting molecular and physiological response mechanisms to high solar radiation in cyanic and acyanic leaves: a case study on red and green basil.

Authors :
Tattini, Massimiliano
Sebastiani, Federico
Brunetti, Cecilia
Fini, Alessio
Torre, Sara
Gori, Antonella
Centritto, Mauro
Ferrini, Francesco
Landi, Marco
Guidi, Lucia
Source :
Journal of Experimental Botany. Apr2017, Vol. 68 Issue 9, p2425-2437. 13p.
Publication Year :
2017

Abstract

Photosynthetic performance and the expression of genes involved in light signaling and the biosynthesis of isoprenoids and phenylpropanoids were analysed in green ('Tigullio', TIG) and red ('Red Rubin', RR) basil. The aim was to detect the physiological and molecular response mechanisms to high sunlight. The attenuation of blue-green light by epidermal anthocyanins was shown to evoke shade-avoidance responses with consequential effects on leaf morpho- anatomical traits and gas exchange performance. Red basil had a lower mesophyll conductance, partially compensated by the less effective control of stomatal movements, in comparison with TIG. Photosynthesis decreased more in TIG than in RR in high sunlight, because of larger stomatal limitations and the transient impairment of PSII photochemistry. The methylerythritol 4-phosphate pathway promoted above all the synthesis and de-epoxidation of violaxanthin-cycle pigments in TIG and of neoxanthin and lutein in RR. This enabled the green leaves to process the excess radiant energy effectively, and the red leaves to optimize light harvesting and photoprotection. The greater stomatal closure observed in TIG than in RR was due to enhanced abscisic acid (ABA) glucose ester deglucosylation and reduced ABA oxidation, rather than to superior de novo ABA synthesis. This study shows a strong competition between anthocyanin and flavonol biosynthesis, which occurs at the level of genes regulating the oxidation of the C2-C3 bond in the dihydro-flavonoid skeleton. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00220957
Volume :
68
Issue :
9
Database :
Academic Search Index
Journal :
Journal of Experimental Botany
Publication Type :
Academic Journal
Accession number :
123453025
Full Text :
https://doi.org/10.1093/jxb/erx123