Figure 7.

OsMADS26 negatively regulates water stress tolerance. Six independent lines: overexpressing (OX2) or down-regulated (DR5-2 and DR3-1) OsMADS26 and corresponding control lines transformed with empty vectors (OX0 and DR0) or the wild type (WT) were used for this experiment. A, Drought stress was applied on 20-d-old plants growing in the greenhouse in pots by stopping watering during 18 d followed by 15 d of rewatering. The pictures were taken 15 d after rewatering. B, RWC of plants was measured on the last expanded leaf before and at 5, 11, and 15 d after watering stopping. Mean values and se were calculated from five individual plants for each line. C and D, qRT-PCR expression analysis of drought- and salt-responsive rice genes RAB21 (C) and SALT (D) in control and transgenic plants before and during drought stress. RNA were extracted from leaves of two plants of each line that had closest RWCs. We did not measure gene expression 15 d after the water deficit period, because the control and MADS26-overexpressing plants were already highly damaged. Means and se were from two individual plants for each line. A Student’s t test was done to establish whether the RWC or the gene expression level in transgenic lines was different from corresponding control line. *, Significant difference with P < 0.05; **, significant difference with P < 0.01; ***, significant difference with P < 0.001.