Functional Characterization of Fer-Ts, a Temperature-Sensitive FERONIA Mutant Allele That Alters Root Hair Growth

The study focused on the fer-ts mutant, a temperature-sensitive variant of the FERONIA gene, which affected root hair growth in plants. At normal temperatures (20°C), fer-ts seedlings developed normally, but at elevated temperatures (30°C), they failed to form root hairs. The mutation involved a G41S substitution in the extracellular domain of FERONIA, leading to increased protein turnover at higher temperatures. While both wild-type and fer-ts mutants showed inhibited tip-growth with RALF1 peptides at normal temperatures, fer-ts mutants were resistant to RALF1 at elevated temperatures. Additionally, fer-ts seedlings exhibited altered ROS accumulation and mimicked constitutive fer mutant responses to various plant hormones at higher temperatures. The study suggested that the fer-ts phenotypes might not be directly due to loss of RALF1 peptide binding, as the mutated glycine was not in the known binding domains.