关键词: 甜瓜, MeP5CS, 序列分析, 表达, 丛枝菌根真菌, 水分胁迫

Abstract: Using designed primers based on the conserved amino acid sequences of known drought-related genes to amplify cDNA fragments from melon（Cucumis melo L.）by RT-PCR，a drought-related gene named MeP5CS was obtained. Bioinformatics analysis indicated that the full-length of cDNA sequence was 1 000 bp，which contained an open reading frame of 753 bp and encoded a protein of 250 amino acid residues with a calculated molecular weight of 82.18 kD and isoelectric point of 4.90. The MeP5CS protein showed 94%，81% and 73% similarity to the P5CS from Aegiceras corniculatum，Actinidia deliciosa and Vitis vinifera. The protein include α-helix（40.2%），β-turn（25.2%），random coil（34.6%）and a cleavage site between nineteen and twenty amino acid residues. The protein is a hydrophobic protein and there is two transmembrane helix and thirteen phosphorylation sites. The result ofRT-PCR analysis indicated that MeP5CS expression levels were different in roots，stems and leaves，and it was the highest in roots and middle in stems，lower in leaves. The results showed that the AMF can induce expression of MeP5CS gene in melon under water stress，and enhance the drought resistance of melon；Expression differences in tissues were related to different tissues and the duration of water stress. Under water deficit，AMF could increase Pro accumulation in melon leaves，gene expression and proline accumulation were positively correlated.

Key words: melon, MeP5CS, sequence analysis, expression, AMF, water stress