Cloning and expression analysis of a floral related MADS-box gene BlMADS1 from Betula luminifera

Key words: 
• forest tree breeding /
• Betula luminifera /
• flowering /
• MADS-box /
• expression analysis

Abstract: As a highly conserved transcription factor family in plants, MADS-box genes play important roles in floral development and regulation of other developmental processes. However, few floral related MADS-box genes have been characterized in Betula luminifera. In this study, a MADS-box gene, BlMADS1, was cloned from Betula luminifera by using homologous cloning and rapid amplification of cDNA ends （RACE） methods. Afterward expression analysis was also conducted. Results of the sequence analysis indicated that BlMADS1 probably had two different transcripts--one was 1 150 bp in length and contained a 765 bp open reading frame （ORF） encoding 254 amino acid residues. This protein was a typical MADS-box protein belonging to the AP1/SQUA subfamily. The other transcript contained an insertion of 162 bp at the 3-terminal. The ORF of this transcript was only 690 bp in length encoding 229 amino acid residues with a truncated C terminal, which may have been caused by introns alternative splicing. The expression analysis also indicated that BlMADS1 was expressed in all tissues, but showed different expression patterns on its two transcripts during inflorescence development. During male inflorescence development, the highest expression of both these two transcripts was detected in the germinating male inflorescence; whereas, during development of the female inflorescence, the highest level of BlMADS1L was shown in the germinating female inflorescence buds and the highest level of BlMADS1S was found in the developing female inflorescence. Our study provides basic knowledge about MADS-box genes in Betula luminifera, and will be facilitate further investigation of BlMADS1s function and regulation mechanism in future. ［Ch, 6 fig. 1 tab. 27 ref.］