Fig. 8.

Silencing of GhRAF4 and GhMEKK12 compromises cotton tolerance to drought stress. a A positive control plant. b Quantitative RT-PCR analysis of expressions of GhRAF4 and GhMEKK12 in mock plants (TRV2:00) and VIGS plants (TRV2:GhRAF4 and TRV2:GhMEKK12). The cotton UBI1 gene was used as internal control. Error bars denote the standard deviation calculated from three independent experiments. c Phenotype of mock plants and VIGS plants under drought stress. d – i Several physiological indexes measured in the target gene-silenced plants and mock plants under normal growing condition (control) and drought treatments. d Proline content. e MDA content. f SOD activity. g POD activity. h relative leaf watering content. i relative soil watering content. j Images of stoma in the target gene-silenced plants and mock plants under normal growing conditions (control) and drought treatment. k Comparative stomatal aperture measurements. Ratio of stomata length to width was determined in the target gene-silenced plants and mock plants under normal growing conditions (control) and drought treatment. Error bars denote the standard deviation calculated from three independent experiments. Asterisks represent Student’s t-test in statistical analysis for significant differences: *P < 0.05; **P < 0.01