encoding GDP-D-mannose pyrophosphorylase from celery enhanced the accumulation of ascorbic acid and resistance to drought stress in .

Ascorbic acid (AsA) is an important nutrient in celery, the conversion of D-mannose-1-P to GDP-D-mannose catalyzed by GDP-D-mannose pyrophosphorylase (GMPase) represents the first committed step in the biosynthesis of AsA. To clarify the function of the gene of celery, the gene was cloned from celery cv. 'Jinnan Shiqin' . It contains an open reading frame (ORF) with the length of 1,086 bp, encoding 361 amino acids. AgGMP protein was highly conserved among different plant species. Phylogenetic analysis demonstrated that the GMP proteins from celery and carrot belonged to the same branch. AgGMP protein was mainly composed of three α-helixes and certain random coils. No signal peptide was found in the AgGMP protein. The subcellular localization indicated that the AgGMP protein was located in the cytoplasm. The relative expression levels of in 'Jinnan Shiqin' were significantly up-regulated at 2 h and 4 h under drought stress treatments. AsA contents in transgenic lines hosting gene were higher than that in wild type plants, and the root lengths were also longer in the MS medium containing 300 mM mannitol. The present study provides useful evidence for the functional involvement of in regulating AsA accumulation and response to drought stress in celery.