Abstract
In grapevine, trans-Resveratrol (tR) is produced as a defence mechanism against stress or infection. tR is also considered to be important for human health, which increases its interest to the scientific community. Transcriptomic analysis in grapevine cell cultures treated with the defence response elicitor methyl-β-cyclodextrin (CD) revealed that both copies of PHOSPHOENOLPYRUVATE CARBOXYLASE KINASE (PPCK) were down-regulated significantly. A role for PPCK in the defence response pathway has not been proposed previously. We therefore analysed the control of PPCK transcript levels in grapevine cell cultures and leaves elicited with CD. Moreover, phosphoenolpyruvate carboxylase (PPC), stilbene synthase (STS), and the transcription factors MYB14 and WRKY24, which are involved in the activation of STS transcription, were also analysed by RT-qPCR. The results revealed that under CD elicitation conditions PPCK down-regulation, increased stilbene production and loss of PPC activity occurs in both tissues. Moreover, STS transcripts were co-induced with MYB14 and WRKY24 in cell cultures and leaves. These genes have not previously been reported to respond to CD in grape leaves. Our findings thus support the hypothesis that PPCK is involved in diverting metabolism towards stilbene biosynthesis, both for in vitro cell culture and whole leaves. We thus provide new evidence for PEP being redirected between primary and secondary metabolism to support tR production and the stress response.
Highlights
Grapevine, Vitis vinifera L., induces biosynthesis of the phytoalexin stilbene as part of its stress defence response
Grape VvPPCK Genes Are Down-Regulated in Response to Elicitation
0.05; As the response of intact leaves to CD treatment was delayed relative to the response of the cell cultures, we explored the regulation of VvMYB14, VvWRKY24, VvSTS36, and
Summary
Vitis vinifera L., induces biosynthesis of the phytoalexin stilbene as part of its stress defence response. The most studied stilbene in this response is trans-Resveratrol (trans-3,5,4’-trihydroxystilbene, tR). Stilbenes play important roles in plant responses to both abiotic [1,2] and biotic stresses, since they display strong antimicrobial and antifungal activities [3,4,5]. Many studies have reported human health benefits resulting from the dietary consumption of stilbenes. TR has been largely studied for its antioxidant, antiinflammatory, immunomodulatory and anti-angiogenic effects, and for its potential roles in chemoprevention of cancer and cardiovascular diseases [6,7,8]. Stilbene biosynthesis from a sugar carbon source in primary metabolism involves the transformation of sugar into erythrose-4 phosphate (E4P) via the pentose phosphate pathway and phosphoenolpyruvate (PEP) via glycolysis.
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