Understanding Pollen - Pistil Interaction as a Basis Towards Improving Reproductive Yields in Plants

The project addresses how flowering plants achieve fertilization, which if unsuccessful will result in reproductive failure, devastating agricultural productivity. Pollen grains germinate on the stigma, the receptive surface of the female organ pistil. Each pollen grain hydrates and extrudes a pollen tube whose function is to transport two sperm cells carried in its cytoplasm to the female gametophyte inside an ovule, usually located at some distance from the stigma. Recent research in plant reproduction has produced critical insights into how a pollen tube targets the female gametophyte (where the egg apparatus is located) through a female-guided process and how the pollen tube, once inside the female gametophyte, achieves sperm release to enable fertilization. Yet mechanisms that underlie the critical first pollen-pistil interactive steps on the stigma, i.e. adhesion of pollen grains on the stigma, pollen hydration, activation and extrusion of the pollen tube to penetrate the stigmatic tissue, remain unclear. The study utilizes the model plant Arabidopsis to elucidate how these early events are orchestrated. In particular, we examine the contribution by three related receptor kinases (RKs) expressed in the stigma, FERONIA (FER), HERCULES1 (HERK1) and RK7.