Figure 2.
Mutants 4442-4 and 4255-1 have increased PDH1pro:LUC2 activity and increased Pro accumulation at low ψw. A, Representative false-color luminescence images of the wild type (W.T.) and mutants in the unstressed control and after 96 h at −1 MPa low-ψw treatment. B, Quantification of PDH1pro:LUC2 activity in 4442-4 and 4255-1. Data are means ± se (n = 4–15). Significant differences (P ≥ 0.05) compared with the wild type in the same treatment are marked with asterisks. Luminescence intensities are given in photons (p) per second (s) per cm2 per steradian (sr). C, Pro accumulation in unstressed control (−0.25 MPa) or low-ψw stress (−1.2 MPa) for the wild type and mutants. FW, Fresh weight. Data are means ± se (n = 3–9). Significant differences (P ≥ 0.05) compared with the wild type in the same treatment are marked with asterisks. Note that the wild type is the unmutagenized PDH1pro:LUC2 line for all experiments in A to C. D, PDH1 gene expression in Col-0 wild type, 4442-4, and two T-DNA alleles of cyp86a2 in the unstressed control treatment or at 96 h after transfer to −1.2-MPa stress. Data are means ± se (n = 3). Significant differences (P ≥ 0.05) compared with the wild type in the same treatment are marked with asterisks. The expression of additional Pro metabolism genes in these mutants is shown in Supplemental Figure S4.