Identification and in silico Analysis of Glutathione Reductase Transcripts Expressed in Olive (Olea europaea L.) Pollen and Pistil

Glutathione (GSH) protects proteins against oxidation of their thiol-containing groups, by alternatively becoming the subject of oxidation, forming glutathione disulfide (GSSG). Appropriate GSH:GSSG levels are maintained by glutathione reductase (GR), a homodimeric flavoprotein which uses NADPH to reduce one GSSG molecule to two of GSH. This enzyme has been characterized in several species, and described as highly conserved, with two isoforms only. Heterogeneity and discticntiveness of plant reproductive tissues led us to investigate the presence of GR sequences. A de novo assembled and annotated olive reproductive transcriptome was subjected to screening, which allowed us to identify at least 11 GR homologues (1 pollen-specific and 10 from pistils). Primers were designed, and full-length sequences were obtained through PCR. In silico analysis, including phylogeny, 3-D modeling of N-terminus, and prediction of cellular localization and post-translational modifications was carried out to shed light into the involvement of olive pollen-intrinsic GR in reproductive development.

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