Xuhong Zhou

Cytological, molecular mechanisms and temperature stress regulating production of diploid male gametes in Dianthus caryophyllus L.

In plant evolution, because of its key role in sexual polyploidization or whole genome duplication events, diploid gamete formation is considered as an important component in diversification and speciation. Environmental stress often triggers unreduced gamete production. However, the molecular, cellular mechanisms and adverse temperature regulating diplogamete production in carnation remain poorly understood. Here, we investigate the cytological basis for 2n male gamete formation and describe the isolation and characterization of the first gene, DcPS1 (Dianthus Caryophyllus Parallel Spindle 1). In addition, we analyze influence of temperature stress on diploid gamete formation and transcript levels of DcPS1. Cytological evidence indicated that 2n male gamete formation is attributable to abnormal spindle orientation at male meiosis II. DcPS1 protein is conserved throughout the plant kingdom and carries domains suggestive of a regulatory function. DcPS1 expression analysis show DcPS1 gene probably have a role in 2n pollen formation. Unreduced pollen formation in various cultivation was sensitive to high or low temperature which was probably regulated by the level of DcPS1 transcripts. In a broader perspective, these findings can have potential applications in fundamental polyploidization research and plant breeding programs.

Comparison of lisianthus (Eustoma grandiflorum) cultivars based on the selected regeneration media using anther culture

Double haploids in lisianthus cultivars were produced using anther culture. The anther of ‘Art Peach’ was cultured on the Murashige and Skoog (MS) medium with 3% sucrose with auxin and cytokinin. The highest frequency of calli developed from anthers (100%) and green plantlets per 100 calli (60 regenerants) was observed on the medium containing 8 mg·L−1 N6-benzyladenine (BA) and 0.1 mg·L−1 naphthaleneacetic acids (NAA). When anthers were cultured on the medium supplemented with 2 mg·L−1 BA and 0.5 mg·L−1 NAA, 33.3% of calli formed plantlets. Using the anther culture, callus induction and plantlets regeneration in five cultivars were developed differently, suggesting that the genotype might predetermined anther culture response. These results indicate that a highly efficient new microprogation technique can be provided by anther culture in vitro for lisianthus. Anther culture in vitro can provide a highly efficient new microprogation technique for lisianthus.