Table I.

Mutants defective in acquired thermotolerance

Homozygous T-DNA insertion mutants, backcrossed once to wild-type Col-0, were tested for acquired thermotolerance as 7-d-old light-grown seedlings after either S acclimation and 120 min at 45°C (7 d [step] column) or gradual acclimation and 150 min at 45°C (7 d [grad] column). Assays were repeated a minimum of three times with at least 12 seedlings and values are expressed as seedling viability as a percent of wild type. For genes for which two insertion mutants were obtained, values for the two lines are indicated. The maximum sd was ±20%, and all values are significantly different from wild type, with a P value ≥ 0.5. Documentation of the homozygosity of the mutants and absence of full-length RNA is provided in Supplemental Figure S5. Ten other mutants shown to be homozygous but to not have a heat stress phenotype were HSFB1 At4g36990; expressed protein At5g67600; LTI78 At5g52310; DREB2A At5g05410; Fer1 At5g01600; immunophilin At4g25340; stress-induced protein At4g12400; ROF1 At3g25230; galactinol synthase At2g47180; and HSFA2 At2g26150. These mutants were not backcrossed to wild type because of the absence of phenotype.

cis-ElementsClusterDescriptionAccession7 d (Step)7 d (Grad)Max Fold Induction
HSE45Hsp101 (hot1-3)At1g7431000106
HSE7APX2 (two insertions)At3g0964030/2020/20744
63APro oxidase (two insertions)At3g3077520/2040/407
HSE41Hsp110 (HSP70-15)At1g79920406013
42Choline kinaseAt1g74320604010
DRE25Thaumatin (two insertions)At4g3601060/6060/609