Host: Matt Evans
Tetsuya Higashiyama
Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Japan
Pollen tube guidance for successful reproduction of flowering plants involves complex cell-to-cell communication. We have been working on pollen tube guidance in living materials by using two model plant species, Torenia and Arabidopsis. Defensin-like peptide LUREs are pollen tube attractants of these species working in a short distance which are secreted by two synergid cells (Science 2001; Nature 2009; PLoS Biol. 2012). To understand the molecular mechanism of pollen tube guidance, we have been taking two approaches of live-cell study (for reviews, Cell Growth Differ. 2013; Annu. Rev. Plant Biol. 2015). The first approach is to use precisely defined semi in vitro system, including development of various microfluidics devices (e.g., RSC Adv. 2013). Recent semi in vitro studies combined with synthetic chemistry lead to discovery of novel intercellular signaling molecules involved in pollen tube guidance. PRK6 of Arabidopsis is a receptor kinase, which is critical in sensing of AtLURE1 peptide (Nature 2016). Arabinogalactan sugar chain AMOR derived from ovular sporophytic tissues of Torenia is critical to make pollen tubes competent before attraction by LUREs (Curr. Biol. 2016; Plant Physiol. 2017). Development of fluorescent small molecules is also in progress for single molecule or super-resolution imaging of cellular signaling (e.g., Angew. Chem. Int. Ed. 2015). The second approach is based on in vivo imaging. We have shown that pollen tube guidance is intimately related with double fertilization (e.g., Dev. Cell 2013; Cell 2015). By using two-photon microscopy, we have succeeded in visualizing pollen tube guidance in the pistil tissue of Arabidopsis. In this talk, I will introduce our interdisciplinary approaches and will talk about how pollen tubes are precisely navigated.