Abstract
The first step of plant-specific protein O-glycosylation is the hydroxylation of proline residues catalyzed by prolyl 4-hydroxylases (P4Hs). It is necessary to prevent plant-specific glycosylation to produce functional non-plant derived proteins in plants. In this study, we investigated the effects of the inhibition and suppression of P4Hs in tobacco on growth and O-glycosylation of ectopically expressed sporamin, which is a sweet potato protein containing single O-glycosylation site.
The treatment of α,α'-dipyridyl, an inhibitor of P4Hs, suppressed the growth of tobacco plants significantly. To repress the expression of each type of P4H in tobacco, we transformed tobacco with RNAi constructs against either type 1 or type 2 P4H. We obtained transgenic plants whose mRNA level of either of the P4Hs were partially decreased. In these plants, no obvious growth defects were observed. Then, we crossed them with each other or with a tobacco plant expressing sporamin, and obtained progenies. We will report the effects of P4H inhibitor and the reduction of the expression of P4Hs on plant growth and protein O-glycosylation.