Minisymposium 14: Reproductive development

Abs # 27002: Functional Study of SOLO DANCERS, a Gene Required for Meiosis in Arabidopsis

Presenter:	Li, Wuxing , wql103@psu.edu
Authors	Li, Wuxing  (A) (B)  Timofejeva, Ljudmilla  (A) (C)  Ma, Hong  (A) (B)
Affiliations:	(A): Department of Biology and the Huck Institute of Life Sciences (B): Intercollegiate Program in Plant Physiology, Pennsylvania State University, University Park, PA 16802 (C): Department of Plant Genetics, Estonian Agricultural University, Harku, Harju maakond 76902, Estonia
Web Site:	http://www.bio.psu.edu/directory/homepages/hxm16.action

The SOLO DANCERS (SDS) gene is important for homolog synapsis, recombination, and bivalent formation (Azumi et al., 2002). We previously analyzed an Arabidopsis solo dancers (sds) Ds insertional mutant, which is male and female sterile due to defective meiotic recombination and synapsis. SDS is expressed specifically in male and female meiocytes and encodes a putative novel cyclin. Therefore we propose that SDS may play roles specifically in regulating the progression of meiotic cell cycle. To further understand its function in meiosis, we examined homologous chromosome paring and the formation of recombination nodules and synaptonemal complexes with electron microscopy. Electron microscopy results showed that the sds mutant could form axial elements at early stages of prophase I (premeiotic interphase and leptotene), but is defective in later stages in forming full-length synaptonemal complexes (SC). The ratio of the length of synapsed chromosomes to the length of chromosomes with axial elements in sds was significantly lower than that in wild-type meiocytes. Abnormal SC structures were also found in sds. In addition, we studied the genetic interactions of SDS with AtSPO11-1 and SYN1/DIF1. AtSPO11-1 is a homolog of the Saccharomyces cerevisiae SPO11 gene (Grelon et al., 2000), and SYN1/DIF1 is a homolog of the yeast Rec8 gene that is essential for sister chromatid cohesion and normal chromosome condensation (Bai et al., 1999; Bhatt et al., 1999). Both of these genes are required for normal Arabidopsis meiosis. Phenotypic analysis showed that the meiotic defect of the double mutants is similar to that of the sds single mutant. In addition, the sds syn1 double mutants showed a defective phenotype similar to that of the syn1 single mutant. Therefore, SDS may function downstream of the AtSPO11-1 ; however, it is required for the normal meiotic recombination and synapsis. Further analysis of these interactions would help us to dissect the network of mechanisms underlying Arabidopsis meiosis. This work is supported by an NIH grant.