Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/1997
Publication Date: N/A
Technical Abstract: The temperature sensitivity of chlorophyll accumulation has been used to identify acquired thermotolerance in higher plants. This study describes the initial characterization of an acquired thermotolerance mutant of Arabidopsis thaliana. This acquired thermotolerance mutant was selected by screening an M2 population of RLD1 Arabidopsis thaliana seedlings derived from seeds treated with the mutagen ethyl methane sulfonate. Etiolated seedlings were preincubated at 38 deg C for 4 h to induce thermotolerance and then challenged at 44 deg C for 30 min in the dark. Preincubated RLD1 seedlings turned green within 24 h when exposed to continuous light. The mutant seedlings selected were light green within 24 h, but attained full Chl levels within 72 h. This delayed pattern of chlorophyll accumulation was observed in control RLD1 seedlings that had not been exposed to the 38 deg C preincubation. Analysis of the M5 population of seedlings derived from the acquired thermotolerance mutant revealed reduced protection levels compared with control RLD1 seedlings. The mutant exhibits an increased high temperature sensitivity, yet shows no shift in the preincubation temperature providing acquired thermotolerance. This work was supported in part by grant no. 96-35100-3168 from the NRI Competitive Grants Program/USDA.