Genome-wide analysis of gene expression reveals gene regulatory networks that regulate chasmogamous and cleistogamous flowering in Pseudostellaria heterophylla (Caryophyllaceae).

BACKGROUND: Pseudostellaria heterophylla produces both closed (cleistogamous, CL) and open (chasmogamous, CH) flowers on the same individual but in different seasons. The production of CH and CL flowers might be in response to environmental changes. To better understand the molecular mechanisms of CH and CL flowering, we compared the transcriptome of the two types of flowers to examine differential gene expression patterns, and to identify gene regulatory networks that control CH and CL flowering. RESULTS: Using RNA sequencing, we identified homologues of 428 Arabidopsis genes involved in regulating flowering processes and estimated the differential gene expression patterns between CH and CL flowers. Some of these genes involved in gene regulatory networks of flowering processes showed significantly differential expression patterns between CH and CL flowers. In addition, we identified another 396 differentially expressed transcripts between CH and CL flowers. Some are involved in environmental stress responses and flavonoid biosynthesis. CONCLUSIONS: We propose how the differential expression of key members of three gene regulatory modules may explain CH and CL flowering. Future research is needed to investigate how the environment impinges on these flowering pathways to regulate CH and CL flowering in P. heterophylla.

Subcellular localization of calcium during Alpinia mutica Roxb. (Zingiberaceae) style movement.

The subcellular localization of calcium in Alpinia mutica Roxb. during style movement was studied in two morphs. In the styles, Ca-antimonate precipitates (ppts) were principally located in apoplasts, with some minimal accumulation in the nucleus. At different movement, stages of movement, the ppts in the abaxial and adaxial sides changed, and no lateral gradient of ppts in the apoplast was established. The increase or decrease of ppts in the apoplast was not accompanied with equivalent changes in the cytoplasm. These results indicate that calcium could not affect the curvature by inhibiting cell elongation but may play a role in style movement by acting as a secondary messenger. EGTA-treatment affected style movement, providing further evidence supporting a role for calcium as a secondary messenger.