biostudies-literatureGe ZNational Natural Science Foundation of ChinaNIGMS NIH HHS1596-1600https://www.ebi.ac.uk/biostudies/studies/S-EPMC5964610biostudies-literatureUnknown358(6370)In flowering plants, fertilization requires complex cell-to-cell communication events between the pollen tube and the female reproductive tissues, which are controlled by extracellular signaling molecules interacting with receptors at the pollen tube surface. We found that two such receptors in <i>Arabidopsis</i>, BUPS1 and BUPS2, and their peptide ligands, RALF4 and RALF19, are pollen tube-expressed and are required to maintain pollen tube integrity. BUPS1 and BUPS2 interact with receptors ANXUR1 and ANXUR2 via their ectodomains, and both sets of receptors bind RALF4 and RALF19. These receptor-ligand interactions are in competition with the female-derived ligand RALF34, which induces pollen tube bursting at nanomolar concentrations. We propose that RALF34 replaces RALF4 and RALF19 at the Science (New York, N.Y.)<i>Arabidopsis</i> pollen tube integrity and sperm release are regulated by RALF-mediated signaling.PMC596461031620103903R01 GM109080award339230Du SMoura DSHou SBergonci THuang QZhao YZou YQu LJLiu MCRuan HGu HDresselhaus TZhong SXiao JDong JCheung AYWu HMGe ZGarcia-Valencia LELuo XLai Lfalse<i>Arabidopsis</i> pollen tube integrity and sperm release are regulated by RALF-mediated signaling.In flowering plants, fertilization requires complex cell-to-cell communication events between the pollen tube and the female reproductive tissues, which are controlled by extracellular signaling molecules interacting with receptors at the pollen tube surface. We found that two such receptors in <i>Arabidopsis</i>, BUPS1 and BUPS2, and their peptide ligands, RALF4 and RALF19, are pollen tube-expressed and are required to maintain pollen tube integrity. BUPS1 and BUPS2 interact with receptors ANXUR1 and ANXUR2 via their ectodomains, and both sets of receptors bind RALF4 and RALF19. These receptor-ligand interactions are in competition with the female-derived ligand RALF34, which induces pollen tube bursting at nanomolar concentrations. We propose that RALF34 replaces RALF4 and RALF19 at the 2017-01-01T00:00:00Z2017 Dec2025-04-04T01:26:35.546Z2019-03-26T23:38:20ZS-EPMC59646102924223410.1126/science.aao3642