MILDEW RESISTANCE LOCUS O Function in Pollen Tube Reception Is Linked to Its Oligomerization and Subcellular Distribution

摘要

Sexual reproduction in flowering plants requires communication between synergid cells and a tip-elongating pollen tube () for the successful delivery of sperm cells to the embryo sac. The reception of the relies on signaling within the synergid cell that ultimately leads to the degeneration of the receptive synergid and rupture, releasing the sperm cells for double fertilization. In Arabidopsis (Arabidopsis thaliana), NORTIA, a member of the MILDEW RESISTANCE LOCUS O (MLO) family of proteins, plays a critical role in the communication processes regulating reception. In this study, we determined that MLO function in reception is dependent on MLO protein localization into a Golgi-associated compartment before arrival, indicating that -triggered regulation of the synergid secretory system is important for synergid function during pollination. Additionally, a structure-function analysis revealed that MLO homooligomerization, mediated by the amino-terminal region of the protein, and carboxyl-terminal tail identity both contribute to MLO activity during reception.