Salicylic Acid Biosynthesis and Role in Modulating Terpenoid and Flavonoid Metabolism in Plant Responses to Abiotic Stress - Salicylic Acid: Plant Growth and Development - page 152

inhibition of the accumulation of the flavonoids quercetin, kaempferol and rutin
(Verberne et al. 2000 ; Nugroho et al. 2002 ). This seems an extreme case since the
constitutive production of SA in these plants appears to divert all the isochorismate
available towards SA production, this way preventing its utilization for phe bio-
synthesis and therefore for flavonoid biosynthesis. In support of this idea TMV-
inoculation or SA-treatment to CSA plants did not affect the expression of PAL,
CHS or CM (Guo et al. 2000 ). Under high light stress, the flavonoid biosynthetic
genes have been shown to be coordinately upregulated mainly -not exclusively,
though- by two types of transcription factors (MYB and bHLH) (reviewed by
Grotewold 2006 ).
4 Conclusion
SA has been recognized as a regulatory signal mediating plant response to abiotic
stress such as drought and salinity. SA may affect both isoprenoid and flavonoid
accumulation in leaves both under control and stress conditions. Further research
is however required to better understand how SA mediates the changes in iso-
prenoid and flavonoid metabolism, whether biosynthetic or degradation pathways
are affected and how isoprenoid and flavonoid building blocks are diverted to
specific biosynthetic routes.
Acknowledgments Support for the research of S.M.-B. laboratory was received through grants
BFU2012-32057, BFU2009-07294 and BFU2009-06045 from the Spanish Government, and the
ICREA Academia award funded by the Generalitat de Catalunya. ''We are also very grateful to
the Spanish Government for the ''Juan de la Cierva'' fellowship given to I.H.''.
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