Abstract:

The full-lengh cDNA sequences of the homologous IMP genes encoding myo-inositol monophosphatase，named CmIMP1 and CmIMP2 were cloned from pumpkin（Cucurbita moschata Duch.），using homological cloning method according to the corresponding unigene sequences obtained from the published transcriptome. The GenBank accession numbers for CmIMP1 and CmIMP2 were  KP735607 and KP735608，respectively. Sequence analysis showed that the cDNA sequence length of CmIMP1 is 1 053 bp containing an 810 bp open reading frame（ORF），encoding 269 amino acids. The cDNA sequencelength of CmIMP2 is 945 bp with an ORF of 807 bp，encoding 268 amino acids. Amino acid alignments revealed that the two CmIMP gene sequences contained three conserved domains for lithium-sensitive monophosphatase enzyme and shared high identities with homologous genes from other plants with identity percentage from 63.8% to 94.0%，among which the IMPs from cucumber and muskmelon had the highest identities with them. Real-time PCR analysis suggested that the expression of CmIMP1 and CmIMP2 exhibited tissue specificity with highest in leaves followed by stem hair and 2-day fruit. Real-time PCR analysis for the abiotic stress treatment showed that salt stress，ABA，and drought could induce the expression of CmIMP1. Drought could strongly induce the expression of CmIMP2，then followed by salt stress，while ABA could hardly induce CmIMP2 expression. These results indicated that CmIMP might play significant role in molecular mechanism of pumpkin responding to abiotic stress.

Key words: pumpkin, CmIMP, gene cloning, abiotic stress, real-time PCR