WDL5 is a positive regulator of microtubule reassembly in response to salt stress. A, Cortical microtubules in the cotyledon pavement cells from wild-type (YFP-tubulin) seedlings treated with 125 mm NaCl for the indicated times. B, Cortical microtubules in the cotyledon pavement cells from mutant wdl5-1 (YFP-tubulin) seedlings treated with 125 mm NaCl for the indicated times. C, Cortical microtubules in cotyledon pavement cells from WDL5-overexpressing (YFP-tubulin, OE) seedlings treated with 125 mm NaCl for the indicated times. Scale bar = 20 μm. D, Density of cortical microtubules in A to C quantified using ImageJ software. Data are the mean ± sd of 3 independent experiments with a minimum of 10 cells from 3 seedlings assessed in each experiment. Student’s t test, **P < 0.01. E, Wild-type (Col-0 ecotype), wdl5-1, wdl5-1 expressing Pro_WDL5: WDL5 (Com), and WDL5-overexpressing (OE) seedlings were grown for 5 d and then transferred to plates containing 200 mm NaCl and grown for a further 3 d. F, The survival rates of wild-type (Col-0 ecotype), wdl5-1, wdl5-1 expressing Pro_WDL5: WDL5 (Com), and WDL5-overexpressing (OE) seedlings. Data represent the mean ± sd of 3 independent experiments with a minimum of 80 seedlings assessed in each experiment. Student’s t test, **P < 0.01.