Short day-photoperiod triggers and low temperatures increase expression of peroxidase RNA transcripts and basic peroxidase isoenzyme activity in grapevine buds

Abstract

Expression of peroxidase (Prx) RNA transcripts was studied in grapevine cv. Thompson seedless through use of semi-quantitative RT-PCR. In roots, the three Vitis vinifera Prx ESTs, reported in the genomic facility database from the University of California ( http://cgf.ucdavis.edu), were expressed as RNA transcripts, and three Prx isoenzymes, two basic (PrxB1) and (PrxB2) and a neutral Prx isoenzyme (PrxN1), were detected in root extracts. In buds, although one Prx EST (CB923206) was detected as a RNA transcript, three Prx activities were found in its extract, these same being the two basic isoenzymes found in the roots, and an acidic one (PrxA1) as well. In field grown grapevines, Prx RNA transcript was expressed transiently during bud endodormancy (ED) while under controlled conditions in a growth chamber, a short day (SD) photoperiod triggered expression of the Prx transcript in bud cuttings; low temperature, enhanced its expression level. Because environmental cues that trigger and enhance Prx RNA transcript expression in bud-tissue are the same as those that induce bud-ED in Vitis, the transient expression of Prx EST (CB923206) identified in buds could signal the full extent of ED in grapevines.