Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/1996
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 selection procedures for obtaining acquired thermotolerance mutants of Arabidopsis thaliana. Acquired thermotolerance mutants were selected by screening an M(2) population of RLD1 Arabidopsis thaliana seedlings derived dfrom seeds treated with the mutagen ethyl methane sulfonate. Etiolated seedlings were preincubated at 38 degrees C for 4 hours to induce thermotolerance and then challenged at 44 degrees C for 30 minutes in the dark. Preincubated RLD1 seedlings turned green within 24 hours when exposed to continuous light. Mutant seedlings were selected that failed to turn green within 24 hours, but attained full Chl levels within 72 hours. This delayed pattern of chlorophyll accumulation was observed in control RLD1 seedlings that had not been exposed to the 38 degree C preincubation. Mutants that remained white, yellow or light green after a 72 hour light exposure were discarded. Analysis of seedlings derived from the putative acquired thermotolerance mutants revealed reduced protection levels compared with control RLD1 seedlings. The results of this study show that the temperature sensitivity of chlorophyll accumulation can be used to select plants with altered thermotolerance characteristics.