Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/23/1999
Publication Date: N/A
Interpretive Summary: Acquired thermotolerance is a complex physiological phenomenon that enables plants to survive normally lethal temperatures. Although the phenomenon has been described, the underlying mechanisms responsible for the induced protection remain a mystery. This study describes the selection of mutants with impaired protection systems. These mutants will be used to help identify specific proteins involved in the protection of plants from high temperature stress.
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 level compared with control RLD1 seedlings. The mutant exhibits an increased high temperature sensitivity, yet shows no shift in the preincubation tempera- ture providing acquired thermotolerance. This work was supported in part by grant no. 96-35100-3168 from the NRI Competitive Grants Program/USDA.