Extracellular signal peptide that regulates cell fate (By similarity). Promotes pollen tube growth prolongation in a SKM1 and SKM2-dependent manner, especially under relatively high temperature (at 30 degrees Celsius), thus conferring tolerance against high temperature probably through the maintenance of mitochondrial activity (PubMed:23910659). Expressed at low levels in seedlings. The O-glycosylation (arabinosylation) of the hydroxyproline Pro-91 enhances binding affinity of the CLE43p peptide for its receptor. Belongs to the CLV3/ESR signal peptide family. Extended C-terminus.