Nonsense-mediated decay of sucrose synthase 1 mRNA with induced premature chain termination codon during cold acclimation in winter wheat

Abstract

Cold acclimation induces the expression of cold-regulated genes needed to protect plants against freezing damage. Fourteen candidate genes were identified as being differentially expressed (presence/absence) between cold acclimated and nonacclimated crown and leaf tissues of 2 winter wheat lines using the cDNA-AFLP method. Two TILLING populations originating from the 2 winter wheat lines were further developed in order to create mutant forms of the candidate genes to verify their role in freezing-tolerance formation. Exon 8 of the identified differentially expressed sucrose synthase 1 (Ss1) gene was chosen for mutation detection by high-resolution melting analysis. A total of 75.68 kb of DNA was screened and 2 novel alleles of the Ss1 gene were identified, of which 1 was silent and 1 was a nonsense (premature stop codon) mutation. qRT-PCR analysis showed that premature stop codon mutation has a strong negative effect on Ss1 gene expression in nonacclimated leaves as well as in crowns and leaves collected at 2, 4, and 6 weeks of cold acclimation compared with the wild-type winter wheat line. Further work will reveal the effect of the mutation on cold tolerance of winter wheat and will enable the assessment of the role of Ss1 in the cold acclimation process.