Comparative proteomic analyses reveal the changes of metabolic features in soybean (Glycine max) pistils upon pollination.

Siphonogamy is a critical process in plant reproductive growth, during which numerous cell-cell interaction events occur between pistil and pollen. Previous studies in Solanaceae, Papaveraceae, and Brassicaceae focusing on pollen-stigma recognition in self-incompatible systems have provided many important views. In this study, we profiled the proteome in soybean mature pistils before and after pollination. Comparative analyses of two-dimensional gel electrophoresis maps from un-pollinated and pollinated pistils were conducted. The results showed that 22 proteins were increased and 36 proteins decreased after pollination. Functional categorization showed that most of them were metabolism- and redox-related proteins. The enhancement of primary metabolism, biosynthesis of pollen tube guidance compounds, and adjustment of redox homeostasis system might be helpful for a successful pollination. Quantitative reverse transcript-polymerase chain reaction analysis implied that the regulation of gene expression might happen at both transcriptional and posttranscriptional levels during pollination. This study will enhance our understanding of pollen-stigma interaction in plant sexual reproductive growth.