Characterization of a putative pollen-specific arabinogalactan protein gene, BcMF8, from Brassica campestris ssp. chinensis.

The BcMF8 (Brassica campestris male fertility 8) gene, possessing the features of 'classical' arabinogalactan protein (AGP) was isolated from Brassica campestris L. ssp. chinensis, Makino syn. B. rapa L. ssp. chinensis. This gene was highly abundant in the fertile flower buds but silenced in the sterile ones of genic male sterile A/B line ('ZUBajh97-01A/B') in B. campestris. Expression patterns analysis suggested BcMF8 was a pollen-specific gene, whose transcript started to be expressed at the uninucleate stage and maintained throughout to the pollen at pollination stage. BcMF8 is highly homologous to the known pollen-specific AGP genes Sta 39-4 and Sta 39-3 from B. napus. Isolation and multiple alignment of the homologs of BcMF8 gene in the family Cruciferae indicated that BcMF8 was highly conserved in this family, which reflect the conservation in biological function and importance of this putative AGP gene in plant development. Similarity analysis also demonstrated Sta 39-4 and Sta 39-3 may originate from different genomes.