Abstract: Synthetic oligonucleotides based on the conserved sequence of atp6, cob and cox Ⅱ of other plants were used to prime the synthesis and amplification of the specific fragments by RT - PCR from Citrus unshiu. PCR products were cloned into pBluescrip t ( sk + ) vector and sequenced. Sequencing analysis showed that the deduced amino acid of atp6, cob and coxⅡ shared over 85% , 98% and 96% identities with homologic genes of other plants species respectively. RT - PCR analysis indicated they expressed in the leaf, petal and flower buds during different stages, while not expression in the immature fruit. Southern blot analysis showed that there existed more than one copys in the genome.

Key words: Citrus unshiu, Mitochondrial gene, Cloning, Expression analysis