Fig. 7.

Ectopic expression of BiP delays drought-induced leaf senescence in soybean plants. Drought was induced in wild type and 35S:BiP-4 plants at the V3 developmental stage by withholding irrigation for 7 d. I, normally irrigated plants; DS, drought-stressed plants. Values are given as mean ±SD from three replicates. (A) Chlorophyll loss induced by drought in wild type and 35S:BiP-4 transgenic lines. (B) Total protein content of wild type and transgenic leaves exposed to a 7 d period of drought. (C) Lipid peroxidation in wild type and 35S:BiP-4 leaves. Lipid peroxidation in leaves was monitored by determining the level of TBA-reactive compounds. (D) Induction of the senescence-associated genes NAC1 and NAC3 by drought. Total RNA was isolated from irrigated and drought-stressed leaves of wild type and 35S:BiP-4 lines and gene induction was monitored by quantitative RT-PCR using gene-specific primers.