Figure 4. Temperature induction of PStSN1 activity in transgenic Arabidopsis lines. For temperature induction assays, Arabidopsis plants grown under 20ºC were changed to 4ºC or 37ºC or kept at 20ºC for 4 hrs under darkness. Four independent transgenic Arabidopsis lines harboring PStSN1::GUS constructs (Lines 2B, 5C, 8B and 11A) and one 35S::GUS control line were evaluated. Whole plants were harvested for GUS assays.
(a) GUS activity was measured as nmoles of MU (methylumbelliferone) produced per min per μg of protein and the data measured at 4ºC and at 37ºC were relatively expressed to the 20ºC set of data. Bar graphs represent the average percentage of GUS activity ± SE measured in ten biological replicates.
(b) Histochemical localization of GUS activity in plants of Line 2B after temperature induction treatments.
(c) Assessment of the temperature treatment effectiveness by RT-PCR of genes induced by low (RD-29A) or high (HSP21) temperature (upper panels). Specific Actin-2 transcript amplification was detected in all plants as an internal control for cDNA synthesis (lower panels). M: Molecular Marker 1 Kb; (-) Negative PCR control (without DNA). * denote significant differences (P < 0.05).