Figure 1. Targeting anti-oxidant enzymes to mitochondria increases the survival of acd2 cells.

(a) Total proteins and mitochondrial proteins were isolated from acd2 (a2), a2/m-tAPX and a2/m-CAT plants and tAPX, catalase (CAT) and mitochondrial marker peroxiredoxin (PRX) II F proteins were detected by Western blot analysis. tAPX and CAT were targeted to mitochondria in the a2/m-tAPX and a2/m-CAT plants, respectively. C= Coomassie staining of the membranes. This experiment was done three times with similar results.

(b) Protoplasts isolated from 20 d-old plants were exposed to light for 2.5 h and double-stained with CM-H₂DCFDA to detect H₂O₂ and CMXRos to mark mitochondria. Fifty to sixty protoplasts were examined under laser scanning confocal microscope (LSCM) and representative protoplasts are shown. Staining with CMXRos validated that CM-H₂DCFDA-positive organelles were mitochondria. This experiment was done three times with similar results.

(c, d) The mean fluorescence intensity (MFI) of CM-H₂DCFDA-stained protoplasts determined using flow cytometry (c). Protoplasts were exposed to light for 15 h and the percentage (%) of surviving cells was determined by FDA staining (d). Results are from a single analysis, representative of three independent experiments that showed similar results. The error bars represent SD (n=3). Letters indicate different values using Fisher’s Protected Least Significant Difference (PLSD) test (P < 0.004).