Abstract
Root hair deformation is the first step of the symbiotic nodule development. It has been reported that actin cytoskeleton remodeling in root hair occur within a short period of time after Nod factor (NF) application. We compared the behaviors of the actin cytoskeleton remodeling in Lotus japonicus Gifu and nodulation mutants by fluorescein-phalloidin labeling after NF application. After 10 min of NF application, actin cable through periphery region of root hair became thinner as F-actin in the wild type. However, the actin cable close to the tip region of root hairs was still remained in the all-mutant lines. After 1 hour of NF application, a fine actin network began to re-establish at subapical region in wild type, whereas some mutant lines showed delayed remodeling of the actin filaments. The results indicated that precise rearrangement of actin network in the initial symbiotic response plays important roles for subsequent nodule development.
