Monreal Hermoso, José AntonioLópez Baena, Francisco JavierVidal, JeanEchevarría Ruiz de Vargas, CristinaGarcía-Mauriño Ruiz-Berdejo, Sofía2017-12-042017-12-042010Monreal Hermoso, J.A., López Baena, F.J., Vidal, J., Echevarría Ruiz de Vargas, C. y García-Mauriño Ruiz-Berdejo, S. (2010). Involvement of phospholipase D and phosphatidic acid in the light-dependent up-regulation of sorghum leaf phosphoenolpyruvate carboxylase-kinase. Journal of Experimental Botany, 61 (10), 2819-2827.0022-0957 (impreso)1460-2431 (electrónico)http://hdl.handle.net/11441/67223The photosynthetic phosphoenolpyruvate carboxylase (C4-PEPC) is regulated by phosphorylation by a phosphoenolpyruvate carboxylase kinase (PEPC-k). In Digitaria sanguinalis mesophyll protoplasts, this light-mediated transduction cascade principally requires a phosphoinositide-specific phospholipase C (PI-PLC) and a Ca2+-dependent step. The present study investigates the cascade components at the higher integrated level of Sorghum bicolor leaf discs and leaves. PEPC-k up-regulation required light and photosynthetic electron transport. However, the PI-PLC inhibitor U-73122 and inhibitors of calcium release from intracellular stores only partially blocked this process. Analysis of [32P]phosphate-labelled phospholipids showed a light-dependent increase in phospholipase D (PLD) activity. Treatment of leaf discs with n-butanol, which decreases the formation of phosphatidic acid (PA) by PLD, led to the partial inhibition of the C4-PEPC phosphorylation, suggesting the participation of PLD/PA in the signalling cascade. PPCK1 gene expression was strictly light-dependent. Addition of neomycin or n-butanol decreased, and a combination of both inhibitors markedly reduced PPCK1 expression and the concomitant rise in PEPC-k activity. The calcium/calmodulin antagonist W7 blocked the light-dependent up-regulation of PEPC-k, pointing to a Ca2+-dependent protein kinase (CDPK) integrating both second messengers, calcium and PA, which were shown to increase the activity of sorghum CDPK.application/pdfengAttribution-NonCommercial-NoDerivatives 4.0 Internacionalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Ca2+-dependent protein kinasephosphatidic acidphosphoenolpyruvate carboxylasephosphoenolpyruvate carboxylase kinasephospholipase Cphospholipase DSorghum bicolorinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccesshttps://doi.org/10.1093/jxb/erq114