Abstract:

【Objective】 The mitochondrial F1-ATPase beta subunit gene from embryogenic callus was cloned and its expression during somatic embryogenesis in longan (Dimocarpus longan Lour.) was analyzed in this experiment. 【Method】 The complete cDNA sequence of the mitochondrial F1-ATPase beta subunit gene of longan embryogenic callus was obtained by reverse transcription polymerase chain reaction (RT-PCR) with rapid amplification of cDNA ends (RACE). And the mRNA transcription level of this gene was surveyed by real-time reverse transcription PCR (qRT-PCR) during somatic embryogenesis in longan. 【Result】 The full-length cDNA sequence of longan embryogenic callus mitochondrial F1-ATPase beta subunit gene was 2 099 bp (GenBank accession number FJ222749). It contained a 1 677-nucleotides-long open reading frame (ORF) which encoded a protein of 588 amino acid residues. Homology searches with the deduced amino acid residues indicated that longan mitochondrial F1-ATPase beta subunit gene had a high similarity to other plant mitochondrial F1-ATPase beta subunit gene. According to the 28 mitochondrial F1-ATPase beta subunit gene sequences of animals and plants, the phylogenetic tree showed that it indeed reflected the evolution of animals and plants. It had a single branch because longan mitochondrial F1-ATPase beta subunit gene was firstly cloned. The results showed that the mRNA transcription levels of longan mitochondrial F1-ATPase beta subunit gene were different at the different stages during longan somatic embryogenesis. The highest level occurred at the globular embryo stage and the lowest at the torpedo embryo stage. 【Conclusion】 Longan mitochondrial F1-ATPase beta subunit gene had a high similarity to other plant mitochondrial F1-ATPase beta subunit gene. The highest mRNA transcription level of longan mitochondrial F1-ATPase beta subunit gene occurred at the globular embryo stage.

Key words: longan, somatic embryogenesis, mitochondrial F1-ATPase beta subunit gene, gene cloning, real-time PCR