Cloning and expression analysis of a new anther-specific gene CaMF4 in Capsicum annuum

Our previous study on the genic male sterile-fertile line 114AB of Capsicum annuum indicated a diversity of differentially expressed cDNA fragments in fertile and sterile lines. In this study, a transcript-derived fragment (TDF), male fertile 4 (CaMF4) was chosen for further investigation to observe that this specific fragment accumulates in the flower buds of the fertile line. The full genomic DNA sequence of CaMF4 was 894 bp in length, containing two exons and one intron, and the complete coding sequence encoded a putative 11.53 kDa protein of 109 amino acids. The derived protein of CaMF4 shared similarity with the members of PGPS/D3 protein family. The expression of CaMF4 was detected in both the flower buds at stage 8 and open flowers of the male fertile line. In contrast to this observation, expression of CaMF4 was not detected in any organs of the male sterile line. Further analysis revealed that CaMF4 was expressed particularly in anthers of the fertile line. Our results suggest that CaMF4 is an anther-specific gene and might be indispensable for anther or pollen development in C. annuum.