Transcriptional differences between the male-sterile mutant bcms and wild-type Brassica campestris ssp chinensis reveal genes related to pollen development

A novel male-sterile mutant which lacks mature pollen, Brassisa campestris male sterile (bcms), was identified in Brassica campestris L. ssp. chinensis Makino (syn. B. rapa ssp. chinensis). Genetic analysis revealed that bcms was controlled by a single recessive mutation locus. Genome-wide transcriptional profiling was performed on the flower buds of both the bcms mutant and the wild-type from which it originated, and profiling analysis indicated that there were numerous changes in gene expression attributable to the gene mutation. This mutation resulted in down-regulation of a variety of genes and up-regulated expression of a few other genes. A total of 51 transcript-derived fragments (TDFs) were isolated: 32 specifically and 12 predominantly accumulated in wild-type flower buds, and two specifically and five predominantly accumulated in bcms flower buds. Sequence analysis showed that some of these TDFs share significant similarities with genes involved in different aspects of cellular development, such as signal transduction, cell wall biosynthesis and regulation. Most other TDFs showed no or very poor sequence similarities to entries in any database and might represent new candidate proteins involved in pollen development. Furthermore, spatial and temporal expression pattern analysis of 20 genes derived from cDNA-amplified fragment length polymorphism in different tissues of both the bcms and wild-type plants revealed their complex and dynamic expression patterns. The bcms mutant and the genes isolated in this paper provide excellent material for future studies on the molecular mechanism of male sterility.