Abstract: A differential TDF ( Transcrip t Derived Fragments) in a cDNA-AFLP analysis of buds from male sterile and fertile lines of cabbage was used as a querying probe to blast the GenBank ( http: / /www.ncbi.nlm.nih.gov/BLAST) and Arabidopsis ( http: / /www.arabidopsis.org/BlAST) database. Based on the assembled homologous cDNA sequences, a 490 bp cDNA was amplified and cloned by RT - PCR. Homologous analysis shows that the amplified cDNA has 82% identity on the nucleotide acid sequence, and 56% identity on the amino acids peptide with Arabidopsis gene RALFL8. We designated the gene as BoRALFL1(GenBank accession number DQ059310). We predicted a 240 bp ORF in BoRALFL1 and a 79 amino acids peptide was coded by this cDNA. Further analysis shows that the pepetide is possibly a preprotein with a signal
pepetide and multi-phosphorylation sites, and the C-terminal amino acids of the pepetide are highly conserved among different plant species.

Key words: Broccoli, Brassica oleracea L. var. italica Plancn, RALF, Gene cloning, RT - PCR