[Effects of diverse stresses on gene expression and enzyme activity of glutathione reductase in Brassica campestris.]

A novel glutathione reductase gene (GR2) was isolated from Brassica campestris Longyou 6 by rapid isolation of cDNA ends (RACE). The full-length of cDNA of GR2 was 2073 bp, with an open reading frame (ORF) of 1692 bp. GR2 encoded a protein of 563 amino acids with a deduced molecular mass of about 60.7 kDa and an isoelectric point of 7.9. The real-time quantitative PCR results showed that GR2 was expressed in the roots, stems and leaves in B. campestris, among which the expression of GR2 in leaves was the highest. The transcript levels of GR1 and GR2, and the enzyme activity of glutathione reductase (GR) increased in response to cold temperature, high temperature, drought stress, and salt stress. The results suggested that GR played an important role in coping with diverse stresses in B. campestris. When abscisic acid (ABA) pretreatment was applied before cold temperature, high temperature, drought stress, salt stress, the expression levels of GR1and GR2, and the activity level of GR all significantly increased compared with the single stress, which indicated that ABA could induce GR1 and GR2 gene transcription and GR activity. However, when MAPKK inhibitor (U0126) pretreatment was applied before the above stresses, the expression levels of GR1and GR2 and the activity level of GR significantly decreased compared with the single stress suggesting that U0126 inhibited GR1 and GR2 gene transcription and GR activity.