|O Mahony, Patrick|
Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/1998
Publication Date: N/A
Technical Abstract: The absence of a heat shock protein (HSP) mutant in higher plants has prevented the classical approach of establishing a cause-and-effect relationship between the synthesis of HSPs and the development of thermotolerance. The obstacles caused by the lack of HSP mutants can be circumvented to a certain degree through the analysis of the heat shock response in aneuploid genetic stocks. This study evaluated the relative contribution of individual heat shock proteins to acquired thermotolerance through chromosomal deletions in a di-telosomic series of the hexaploid wheat, Chinese Spring. This study describes the identification of lines within the ditelosomic series of Chinese Spring exhibiting altered levels of acquired thermotolerance. Changes in the temperature sensitivity of chlorophyll accumulation were used as an indicator of acquired thermotolerance. The temperature providing maximum chlorophyll accumulation nunder continuous light was 28 deg C in Chinese Spring leaves (5 to 7 days after planting). A 30 min challenge temperature of 47 deg C prior to light exposure was shown to prevent subsequent chlorophyll accumulation. Preincubation of the wheat leaves at 40 deg C for 4 hr before the 30 min 47 deg C challenge triggered the plants' acquired thermotolerance system resulting in chlorophyll accumulation upon exposure to continuous light. Evaluation of the ditelosomic series revealed reductions in acquired thermotolerance levels in the 7AS and 7DS Chinese Spring lines relative to controls. Two-dimensional SDS polyacrylamide gel analyses have been used to identify specific changes in HSPs.