Isolation of anther-preferentially expressed genes from Chinese cabbage (Brassica campestris L ssp pekinensis)

Dot-differential hybridization and cDNA Southern blot analyses were successfully employed for isolating anther-preferential genes from Chinese cabbage (Brassica campestris L. ssp. pekinensis). A cDNA library was constructed using poly(A)(+) RNAs isolated from developing anthers when the size of newer bud was from 2 mm to 5 mm in length. Forty three anther-preferential cDNA clones out of 230 randomly chosen cDNA clones were isolated by dot-differential hybridization using anther and leaf cDNAs labeled with [alpha-P-32] dATP as probes. Using cDNA Southern blot analysis, another 5 anther-preferential cDNA clones were isolated from 14 clones which were not identified by dot-differential hybridization. Among 48 anther-preferential cDNA clones isolated, 14 clones showed sequence homology with anther- or pollen-specific genes of other plants. Ten randomly chosen anther-preferential clones were investigated for their temporal expression during anther development. The results showed that most of the anther-preferential transcripts examined began to accumulate at the early stage of microspore development and continuously increased to the late stage of anther development.