Abstract: In this study，the genes encoding the mannitol dehydrogenase were cloned from‘Liuhe
Huangxinqin’and‘Ventura’，respectively. The lengths of mannitol dehydrogenase genes from the two
celery cultivars were 1 098 bp，and encoding 365 amino acids. The protein molecular weights of the
enzymes were 39.66 kD and 39.69 kD，and the pI values were 6.79 and 6.78，respectively. There were 17
different nucleotide sites，and 3 different amino acid residues between the mannitol dehydrogenase genes
from the two celery cultivars. Sequence alignment with mannitol dehydrogenase of other plants indicated
that the enzymes were highly conserved. Phylogenetic analysis demonstrated that the enzymes of celery
were closed with coriander，an Apiaceae plant. Real-time quantitative PCR analysis showed that the
mannitol dehydrogenase genes were tissue-specific expressed in the two celery cultivars，the highest
expression level were found in the root. The expression profiles of the mannitol dehydrogenase gene weredetected by real-time quantitative PCR under different stress treatments（4 ℃，38 ℃，0.2 mol · L-1 NaCl
and 20% PEG）in the two celery varieties. Expression profiles analysis showed that level of the induced or
suppressed the mannitol dehydrogenase gene in‘Liuhe Huangxinqin’were larger than in‘Ventura’. The
responses of the mannitol dehydrogenase gene to abiotic stress treatments were different in the two celery
varieties.

Key words: Apium graveolens, mannitol dehydrogenase, gene cloning, abiotic stress, gene expression