BcMF13, a new reproductive organ-specific gene from Brassica rapa. ssp. chinensis, affects pollen development

A transcript-derived fragment (GenBank accession number DN237920.1) accumulated in the wild-type flower buds of Chinese cabbage (Brassica campestris L. ssp. chinensis Makino, syn. B. rapa ssp. chinensis) was isolated and further investigated. The full length DNA and cDNA of the fragment were cloned by rapid amplification of cDNA ends. The gene, BcMF13, encodes a protein of 73 amino acids and is interrupted by an intron of 106 bp (GenBank accession number EF158459). Southern blot analysis revealed that BcMF13 could be a single-copy gene in the Chinese cabbage genome. Sequence blast analysis showed that BcMF13 was a new gene. In EST database, those sequences share 96-98% identity with BcMF13 cDNA all came from flower buds, microspores, anthers of Brassica, which proved BcMF13 homologs closely related to the development of male gametogenesis in Brassica. RT-PCR discovered that it is exclusively expressed in stage four and five flower buds of fertile line, strongly expressed in stamens. Successful suppression of BcMF13 gene expression by RNA antisense strategy greatly reduced the normal pollen grains, suggesting that BcMF13 was essential in pollen development in Brassica.