Fructan biosynthesis gene expression upon cold acclimation in orchardgrass (Dactylis glomerata L.)

Because of the relationship between winter hardiness and fructan accumulation, we measured the fructan content of five orchardgrass germplasm sources considered to differ in winter hardiness. We hypothesized that fructan accumulation upon cold acclimation would increase and cause orchardgrass plants to become more freezing tolerant, and that fructan biosynthesis gene transcripts would be induced upon cold acclimation while fructan degradation gene transcripts would be reduced. Within the context of recent genomic resources, we identified glycoside hydrolase 32 (GH32) genes with likely invertase, fructosyltransferase, and exohydrolase gene functions based on homologies to Triticeae and L. perenne characterized genes. We found that orchardgrass does indeed contain fewer fructosyltransferases than Triticeae or L. perenne, but many unspecified genes with homology to fructan exohydrolases (FEH) and cell wall invertase (CWI) genes.