Abstract:

Peroxiredoxins (Prx) catalyse the reduction of hydrogen peroxide (H₂O₂) and, in association with catalases and other peroxidases, may participate in signal transduction by regulating intercellular H₂O₂ concentration that in turn can control gene transcription and cell signaling. Using virus-induced-gene-silencing (VIGS), 2-Cys Peroxiredoxin (2CysPrx) family and type-II Peroxiredoxin B (PrxIIB) gene were silenced in Nicotiana benthamiana, to study the impact that the loss of function of each Prx would have in the antioxidant system under control (22 °C) and severe heat stress conditions (48 °C). The results showed that both Prxs, although in different organelles, influence the regeneration of ascorbate to a significant extent, but with different purposes. 2CysPrx affects abscisic acid (ABA) biosynthesis through ascorbate, while PrxIIB does it probably through the xanthophyll cycle. Moreover, 2CysPrx is key in H₂O₂ scavenging and in consequence in the regulation of ABA signaling downstream of reactive oxygen species and PrxIIB provides an important assistance for H₂O₂ peroxisome scavenges.

Vidigal P, Martin-Hernandez AM, Guiu-Aragonés C, Amâncio S, Carvalho L (2015) Selective silencing of 2Cys and type-IIB Peroxiredoxins discloses their roles in cell redox state and stress signaling. J Integr Plant Biol 57: 591–601. doi: 10.1111/jipb.12296

Key words: 2-Cys Peroxiredoxin, abscisic acid, ascorbate, heat stress, hydrogen peroxide, peroxisome, type-II Peroxiredoxin B