Abstract
Because of its difficulties with the observation, little is known about the molecular mechanism of angiosperm fertilization. Previously we showed that in Torenia, pollen tube attractant is secreted from the synergid cells. Using this in vitro pollen tube guidance assay, a molecule, which induced competence to the pollen tube to respond to the attractant, was uncovered and named AMOR (activation molecule for response capability). AMOR was heat-stable and was collected in a fraction of arabinogalactan proteins (AGPs). To understand its role for the induction of competence, we investigated strategies to purify sufficient amount of AMOR to characterize its molecular nature, and active fractions obtained from column purification were analyzed further. We also found that AGPs from vegetative tissues of other plant species had some AMOR-like activity. We are now investigating whether AMOR belongs to AGPs and whether sugar chains in the AMOR fraction contribute to AMOR activity.
