Genetic study of glutathione accumulation during cold hardening in wheat

The effect of cold hardening on the accumulation of glutathione (GSH) and i ts precursors was studied in the shoots and roots of wheat (Triticum aestiv um L.) cv. Cheyenne (Ch, frost-tolerant) and cv. Chinese Spring (CS, modera tely frost-sensitive),in a T. spelta L. accession (Tsp, frost-sensitive) an d in chromosome substitution lines CS (Ch 5A) and CS (Tsp 5A). The fast ind uction of total glutathione accumulation was detected during the first 3 d of hardening in the shoots, especially in the frost-tolerant Ch and CS (Ch 5A). This observation was corroborated by the study of de novo GSH synthesi s using [S-35]sulfate. In Ch and CS (Ch 5A) the total cysteine, gamma-gluta mylcysteine (precursors of GSH), hydroxymethylglutathione and GSH contents were greater during the 51-d treatment than in the sensitive genotypes. Aft er 35 d hardening, when the maximum frost tolerance was observed, greater r atios of reduced to oxidised hydroxymethylglutathione and glutathione were detected in Ch and CS (Ch 5A) compared to the sensitive genotypes. A corres pondingly greater glutathione reductase (EC 1.6.4.2) activity was also foun d in Ch and CS (Ch 5A). It can be assumed that chromosome 5A of wheat has a n influence on GSH accumulation and on the ratio of reduced to oxidised glu tathione as part of a complex regulatory function during hardening. Consequ ently, GSH may contribute to the enhancement of frost tolerance in wheat.