Cellular water-potential sensing through biomolecular condensation

Plant materials, growth conditions and stress treatment All the Arabidopsis thaliana mutants and transgenic plants used in this study were in the Columbia (Col-0) background. The T-DNA insertion mutant sam8-1 (SALK_065676) was ordered from the AraShare. The sam8-2 is a CRISPR-edited allele carrying a 1-bp insertion 39 bp downstream of the start codon, which introduces a frameshift and premature stop codon. The resulting protein is MAELQLVEGHQINRRFYPAGDNKLNRSTGNIRRSRSFSRIETIEKT*. The ok130-null mutant was provided by Prof. Pengcheng Wang (Southern University of Science and Technology). Seeds were surface sterilized with 2.5% (v/v) sodium hypochlorite and 70% (v/v) ethanol, stratified for 3 days in the dark at 4 °C, and sown on half-strength Murashige and Skoog (MS), 0.8% (w/v) agar plates supplemented with 1% (w/v) sucrose. Plate media were transferred to a growth chamber under a long-day (16 h light 22 °C/8 h dark 18 °C) photoperiod. For the germination kinetic assay, all seeds of the indicated genotypes were harvested on the same date from plants grown under identical conditions. They were then uniformly dried at 37 °C for 2 weeks to ensure a consistent after-ripening process. Subsequently, the seeds were sown on the same batch of medium and placed in a growth chamber without stratification under a long-day photoperiod (16 h light at 22 °C/8 h dark at 18 °C). Germination rate was calculated as the mean percentage of seeds that had ruptured their seed coats. …