|O Mahony, Patrick|
Submitted to: American Association of Plant Physiologists Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2000
Publication Date: N/A
Technical Abstract: Acquired thermotolerance is a complex physiological phenomenon that enables plants to survive lethal temperatures. This study characterizes the temperature sensitivity of Arabidopsis thaliana using a chlorophyll accumulation bioassay, describes a procedure for selection of acquired thermotolerance mutants, and provides the physiological characterization of fone mutant (AtTS02) isolated by this procedure. Exposure of etiolated Arabidopsis seedlings to 48 or 50C for 30 min blocks subsequent chlorophyll accumulation and is eventually lethal. Arabidopsis seedlings can be protected against the effects of a 50C-30 min challenge by a 4 h preincubation at 38C. By the use of the milder challenge, 44C for 30 min, and protective pretreatment, mutants lacking components of the acquired thermotolerance system were isolated. Putative mutants exhibited chlorophyll accumulation levels (measure of acquired thermotolerance) from 10 to 98% of control seedling levels following preincubation at 38C and challenge at 50C. Genetic analysis showed that the loss of acquired thermotolerance in one of the mutants, AtTS02, was a recessive trait. The pattern of proteins synthesized at 25 and 38C in the RLD and AtTS02 revealed the reduction in the level of a 27 kDa heat shock protein in AtTS02. Genetic analysis showed that the reduction of this protein level was correlated with the acquired thermotolerance phenotype.