|O Mahony, Patrick|
Submitted to: Plant Physiology
Publication Type: Abstract Only
Publication Acceptance Date: 7/16/2000
Publication Date: N/A
Technical Abstract: A study of the ditelosomic series of Chinese Spring wheat identified a number of lines exhibiting an altered capacity to acquire thermotolerance. One such ditelosomic (DT) line is termed DT1BS which refers to the deleted short arm of chromosome 1 in the B genome. Relative to the wild type, this ditelosomic line has the ability to acquire thermotolerance at lower temperatures which when induced provides greater protection to the plant against elevated temperatures. Using a chlorophyll accumulation assay to assess plant health, we show that DT1BS is similar to wild type in that it accumulates maximum chlorophyll levels at 30 C and acquires maximum thermotolerance to a 48 C challenge during a 4 hr preincubation at 40 C. However, DT1BS is able to acquire thermotolerance at temperatures as low as 30 C and at the optimum preincubation temperature of 40 C acquire greater protection than the wild type. 2-D PAGE analysis provides evidence that low wlevels of heat shock proteins are induced in DT1BS at temperatures as low as 30 C. A similar level of induction in wild type is not observed until it is exposed to a temperature of 34 C. This differential heat shock response in DT1BS is not due to an induction of all HSPs since HSP101 and HSP17.6 were shown by western analysis to be similarly induced by elevated temperatures. Analysis of the whole plant response to high temperature stress validated the chlorophyll accumulation assay as an accurate measure of plant health and corroborated the results obtained from tissue sections confirming that acquired thermotolerance in DT1BS is induced at lower temperatures and provides greater protection even at the optimum induction temperature.