Organ-specific expression of β-glucuronidase activity driven by the Arabidopsis heat-shock promoter in heat-stressed transgenic Nicotiana plumbaginifolia.

The expression of the Arabidopsis heat-shock protein (HSP) 18.2 promoter β-D-glucuronidase (GUS) chimera gene was studied in various organs of the transgenic Nicotiana plumbaginifolia during the recovery phase at normal temperatures (20-22  °C) following heat-shock (HS) treatment. The optimum HS temperature for GUS activity in the anthers, petals and capsules was 42  °C, but in immature seeds and the placentas of capsules it was 36  °C and 39  °C, respectively. No apparent GUS activity was observed in any organs except for dry seeds after HS at 45  °C, although the activity in dry seeds was apparent even after HS at 48  °C. After HS at 42  °C, GUS activity in the flower tissues was the highest before anthesis and declined thereafter.