ARS | Publication request: PHENOTYPIC EVALUATION OF ACQUIRED THERMOTOLERANCE MUTANTS OF ARABIDOPSIS THALIANA USING MULTIPLE BIOASSAYS

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: July 24, 2001
Publication Date: April 24, 2001

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 acquired thermotolerance mutants of Arabidopsis thaliana. These acquired thermotolerance mutants were selected by screening M2 populations of Arabidopsis thaliana seedlings derived from mseeds treated with the mutagen ethyl methane sulfonate. Etiolated seedling preincubated at 38@C for 4 h to induce thermotolerance and then challenged at 44@C for 30 min in the dark turned green within 24 h when exposed to continuous light. The mutant seedlings were light green within 24 h, but attained full Chl levels within 72 h. This delayed pattern of chlorophyll accumulation was observed in control seedlings that had not been exposed to the 38@ C preincubation. Analysis of the M3 and M4 populations of seedlings derived from the acquired thermotolerance mutants revealed a range of mutant and wild-type phenotypes when assayed for the sensitivity of hypocotyl elongation, 30C continuous exposure, ion leakage, and seed tolerance to a high temperature challenge. These results suggest that although the chlorophyll accumulation assay was used to isolate these thermotolerance mutants, the population of existing mutants can be subdivided into 5 sensitivity groupings based upon responses to other assay systems.