Abstract：Protocorm-like bodies (PLBs) can be efficiently induced by TDZ from Rosa canina rhizoids. More understandings on the molecular biological mechanism of PLBs induction contributes to the establishment of protocorm-like bodies protocols of cut roses. One important premise of the mechanism study in the molecular biological level is to quickly and accurately clone and screen the key genes during PLBs induction. On the basis of 'conserved sequences' in 5' untranslated regions(5'UTR) of homologous genes with high scores of Malus×domestica, Prunus persica and Fragaria vesca, we designed the forward degenerate primers to directly isolate the cDNA 5'ends of PIN1(pin-formed) and PLT(plethora) of R. canina by PCR amplification using the cDNA template catalyzed by M-MLV reverse transcriptase. The results showed that there were some conserved fragments in the 5' rapid amplification of cDNA ends(5'UTR) of RcPIN1, RcPLT and their homologous genes with high scores of Malus×domestica, Fragaria vesca and Prunus persica, which indicated the above method was practicable. With this method, costly 5'RACE kits were entirely unnecessary because no homopolymer sequence and abridged anchor primers were to be introduced to the 5' ends of cDNA template, for genes from plants of Rosacease family. As a result, this method took advantages of speediness and economy. It is believed that this method will be a practical pathway and worthy reference to identify cDNA 5'ends for some Rosaceae plants.
