Abstract：Class-Ⅰ KNOX(KNOX1) gene is highly conserved homeobox transcription factor in eukaryote, and play a vital role in the process of plant embryogenesis and organ development. Homologue gene of KNOX1 gene was clonded from protocorm-like body of Rosa canina L., through comparison amino acid sequences with other KNOXI gene and phylogenetic analysis, it was named RcKN1 gene. The full length cDNA of RcKN1 was 1 509 bp, with open reading frame(ORF) of 1 185 bp, encoding a protein of 395 amino acids, 5'UTRs of 32 bp and 3'UTRs of 291 bp (GenBank accession No. JN998201). RT-PCR results showed that the gene was only expressed in young organ including leaf bud, floral bud, protocorm-like body, and so on. Constitutive plant expression vector of RcKN1 gene was constructed, its function was analysed by introducing it into tobacco(Nicotiana tabacum L.). A series of novel phenotype were observed on transgenic tobacco, including lobbed leaf, disorder leaf vein, deficit leaves, even leaf like compound leaf, and so on. The results suggest RcKN1 gene performed important function during plant development, which is valuable target gene can be used to study mechanism of leaf development and breed new flower varieties with novel leaf type
