关键词: 三七, RNase-like 基因, 克隆, 表达模式

Abstract: Combining homology cloning approaches with RACE（rapid amplification of cDNA ends）
techniques，the coding sequence of RNase-like major storage protein with differential expression was
cloned from the total RNA of roots and stems of Panax notoginseng，then the full gene sequence was
amplified from the total DNA. As a result，a cDNA sequence containing a 717 bp ORF（open reading
frame）was cloned and named as PMP（GenBank，KC751542），together with a full-length DNA sequence
of 1 074 bp. Analysis of sequence and its phylogenetic tree showed that PMP gene consisted of 2 introns
and 3 exons，encoding a protein of 238 amino acids. The deduced protein，with a predicted molecular mass
of 27.47 kD，contained two conserved domains of RNases，which belonged to the RNase-T2 superfamily
member. The sequence showed 95% identity with that of RNase-like major storage protein in Panax ginseng. Real-time quantitative PCR showed that the expression level of PMP in 3-year-old root was
higher than the other organs. The expression pattern of PMP showed notable correlation with that of main
active components in P. notoginseng，which suggested that it might be involved in the regulation of
secondary metabolism of notoginsenoside and the quality formation.

Key words: Panax notoginseng, RNase-like gene, cloning, expression profile