Isolation and analysis of differentially expressed genes in dominant genic male sterility (DGMS) Brassica napus L. using subtractive PCR and cDNA microarray

Dominant genic male sterility (DGMS) is an important approach to utilize the heterosis of Brassica napus, but the molecular mechanism of DGMS is not well understood. As an initial step towards understanding this event, some pilot studies were performed. Using suppression subtractive hybridization (SSH) and cDNA microarray, about 1200 significantly differentially expressed clones were isolated between the fertile and sterile plants of the homozygous DGMS two-type line, Rs1046AB. Northern blot further demonstrated the credibility of the microarray data. Subsequently, about 400 clones were selected for sequencing and they represented 216 unigenes (212 were up-regulated in fertile buds, and the other 4 were up-regulated in sterile ones). Of the 212 up-regulated genes in forward-subtracted library, 178 homologous sequences could be divided into 17 groups excluding those that encode the unclassified proteins; and the other 34 genes had no homology in the databases at the National Center for Biotechnical Information (NCBI). Furthermore, some important pathways related to male gametogenesis were identified using the program of KEGG Orthology (KO)-Based Annotation System (KOBAS), such as nitrogen metabolism, nitrobenzene degradation and starch and sucrose metabolism.