Peptide signaling in pollen-pistil interactions.

Plant fertilization is achieved through the involvement of various pollen-pistil interactions. Self-/non-self-recognition in pollination is important to avoid inbreeding, and directional and sustainable control of pollen tube growth is critical for the pollen tube to deliver male germ cells. Recently, various secreted peptides (polypeptides) have been reported to be involved in cell-cell communication of pollen-pistil interactions. These include determinants of self-incompatibility, factors for pollen germination and tube growth, and pollen tube attractants. Interestingly, many of them are cysteine-rich peptides/polypeptides (CRPs). In this review, I focus on the peptides involved in pollen-pistil interactions and discuss properties of peptide signaling in each step from pollination to fertilization.