|O Mahony, Patrick|
Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/25/1999
Publication Date: N/A
Technical Abstract: This study characterizes the temperature sensitivity of AtTS02, an Arabidopsis thaliana mutant with reduced acquired thermotolerance. AtTSO2 was chosen from a M3 population of 30 mutants selected as plants exhbiting a delayed accumulation of Chl in the light at 25C compared with control seedlings (our measure of reduced acquired thermotolerance) after a 4 h preincubation at 38C and 30 min exposure to 44C. A more detailed characterization of AtTS02 indicates that this mutant has similar rates of Chl accumulation at 20C and a reduced rate of Chl accumulation at 28C when compared to RLD control seedlings. The temperatures that provide maximum acquired thermotolerance prior to exposure to a high temperature challenge were the same in AtTS02 and RLD seedlings, although the absolute level of thermotolerance was reduced in the mutant. Genetic analysis showed that the loss of acquired thermotolerance in AtTS02 was a recessive trait. Biochemical analysis of the pattern of proteins synthesized at 25 and 38C in the RLD and AtTS02 revealed a distinct reduction in the level of a 27 kDa putative heat-shock protein in AtTS02. Analysis of backcrosses between AtTS02 and RLD showed that the reduction of this protein was correlated with the acquired thermotolerance phenotype. This work was supported in part by grant no. 96-35100-3168 from the NRI Competitive Grants Program/USDA.