Detection of Weak Expression of SOLO DANCERS in the Male Germline Using CYCLIN-DEPENDENT KINASE A1 Coding Sequence

Abstract

Male germline specification is a crucial step in double fertilization in flowering plants. Determining which genes are activated in the male germline, and how those genes are regulated, is essential to understand double fertilization. However, transcription activities in the male germline may be not easy to detect due to low-level expression of some genes and technical difficulties of isolating male germline cells. Here, through a series of gene reporter assays in Arabidopsis, we showed a weak male germline expression pattern of the SOLO DANCERS (SDS) gene, which was confirmed by RT-PCR. Compared to directly fusing the SDS sequence with GFP, adding the coding sequences of other genes such as CDKA1 can greatly enhance the detection of the male germline expression pattern of SDS. We found that SDS expression in the male germline is activated by a novel pathway that differs from the well-known DUO1 regulon. We also developed an SDS-based fluorescence reporter to analyze posttranscriptional regulation in the male germline. Our data suggest that stable gene products of CDKA1 and others may enhance the sensitivity of gene reporters, and the male germline may use diverse pathways to activate gene expression.