Abstract

Arbuscular mycorrhizal (AM) symbiosis is a mutually beneficialinteraction between fungiand plants, contributing to plant fitness and global nutrient cycles.Two paralogous /hydrolase receptorproteins,Arabidopsis KARRIKIN INSENSITIVE 2 (KAI2)and DWARF 14 (D14), recognize butenolides, the smoke compound karrikinsand the plant hormone strigolactones, respectively.Strigolactones induce hyphal branchingofAMfungiin the rhizosphere while rice DWARF14 -LIKE (D14L), the homologue of KAI2 , is indispensable for AM symbiosis establishmentas shown by thecomplete block of AM symbiosis in d14lmutants, suggesting an essential role duringpre-symbiotic communication. The promoter of D14 Lis expressed in the vasculature and the D14L protein shows nucleo-cytoplasmic localization, raising the questionsof how fungal perception in the rhizosphere is mediatedand whether both the cytosolic andthenuclear pools are necessaryfor D14L signaling.