Adhesion and Guidance in Pollination

University Of California-Riverside, Riverside CA

Investigators

Abstract

Lord 0420445 Adhesion and Guidance in Pollination This project concerns plant reproduction. Plants produce seed by fertilization (the fusion of sperm and egg to form a zygote and then an embryo). Flowering plants, which produce all our crops, both food and fiber, have complex reproductive mechanisms which involve adhesion and guidance of the sperm carrying structure, the pollen tube, in the female tissues (pistil) of the flower. Little is known about this phase of reproduction when many guide posts must be traversed in the pistil in order for the sperm cells to be delivered to the egg which resides deep inside the ovary. Recently, a protein has been discovered at the entrance to the pistil in the Easter Lily, which is capable of directing the growing pollen tube tip onto the proper track to the egg cell in the ovary. It acts with another protein that is involved in adhesion and guidance of the pollen tube in the style, the entrance into the ovary. Understanding how these proteins from the pistil interact with the pollen tube to guide its growth to the egg is the focus of this investigation. This is the first such chemotropic peptide (small protein) discovered in plants. Surprisingly, the analogous chemo-attractants in the human reproductive track that guide sperm cells to the egg remain unknown, but in one vertebrate species, the frog, the identity of the sperm chemo-attractant is known and it is also a small protein. Biochemical (using Lily), molecular genetic(using Arabidopsis) and localization studies will be used to study this interaction and thereby gain a better understanding of flowering plant fertilization. The results will be of importance to breeding programs for both crop plants and for the flower industry.