| A class A4 heat shock transcription factor (Hsf) from Medicago sativa L. was compared to a class A1 and a class A4 Hsf from Arabidopsis thaliana. Transient expression assays with beta-Glucuronidase and Luciferase reporter genes were used in a replicated study comparing mesophyll protoplasts from five species, Nicotiana tobaccum, Arabidopsis, M. sativa, M. truncatula and Lotus japonicus. A significant Hsf protein by protoplast interaction (P=0.0162) was detected. The Arabidopsis class A1 activated significantly (P<0.05) higher levels of reporter compared to the Arabidopsis and Medicago class A4 in Nicotiana protoplasts. In Arabidopsis, and M. truncatula and Lotus protoplasts it was the reverse; the A4 Hsf induced higher expression than the A1. The class A4 Arabidopsis and Medicago had comparable activities in M sativa, M. truncatula and Lotus protoplasts. This study revealed that model plant species have differential response which altered the relative activation of Hsf proteins in the heat shock response. |
