Cold Acclimation in Arabidopsis thaliana

Abstract

The abilities of two races ofArabidopsis thaliana L. (Heyn), Landsberg erecta and Columbia, to cold harden were examined. Landsberg, grown at 22 to 24°C, increased in freezing tolerance from an initial 50% lethal temperature (LT5o) of about -3°C to an LT5o of about -6°C after 24 hours at 4°C; LT5o values of -8 to -10°C were achieved after 8 to 9 days at 4°C. Similar increases in freezing tolerance were obtained with Columbia. In vitro translation of poly(A ) RNA isolated from control and coldtreated Columbia showed that low temperature induced changes in the population of translatable mRNAs. An mRNA encoding a polypeptide of about 160 kilodaltons (isoelectric point about 4.5) increased markedly after 12 to 24 h at 4°C, as did mRNAs encoding four polypeptides of about 47 kilodaltons (isoelectric points ranging from 5-5.5). Incubation of Columbia callus tissue at 4°C also resulted in increased levels of the mRNAs encoding the 160 kilodalton polypeptide and at least two of the 47 kilodalton polypeptides. In vivo labeling experiments using Columbia plants and callus tissue indicated that the 160 kilodalton polypeptide was synthesized in the cold and suggested that at least two of the 47 kilodalton polypeptides were produced. Other differences in polypeptide composition were also observed in the in vivo labeling experiments, some of which may be the result of posttranslational modifications of the 160 and 47 kilodalton polypeptides.Many plants become more resistant to freezing temperatures when first exposed to low nonfreezing temperatures, a process known as cold acclimation or cold hardening (11,23 (25). Plants were maintained in a controlled environment chamber at 22 to 24°C under constant illumination from cool white fluorescent lights. Light intensity was approximately 100 ,uE m 2 s-' PAR at soil level, and the RH was about 40 to 50%. Plants were subirrigated as necessary with distilled water. Cold treatment was at 4°C under constant illumination from cool-white fluorescent lights with light intensity ranging from approximately 20 to 50 ,uE m-2 s-' PAR, and the RH was between 75 and 95%. Experiments were performed before the plants had started to bolt, generally about 19 d after planting.For RNA extraction, rosette leaves and stems were excised at soil level, frozen in liquid N2, pulverized using a mortar and pestle, and stored at -80°C prior to extraction.Callus Culture. Arabidopsis (Columbia) seeds were surfacesterilized and placed on semisolid MSa2 medium (MSal) (17) and containing 3% (w/v)

Arabidopsis thaliana CBF1 encodes an AP2 domain-containing transcriptional activator that binds to the C-repeat/DRE, a cis-acting DNA regulatory element that stimulates transcription in response to low temperature and water deficit

“…A. thaliana (L.) Heyn. ecotype RLD plants were grown in pots in controlled environment chambers at 22ЊC under constant illumination with cool-white fluorescent lamps (Ϸ100 mol⅐m Ϫ2 ⅐s Ϫ1 ) as described (13). The effect of low temperature on CBF1 expression was determined by placing pots of plants in a cold room at 2.5ЊC under constant illumination with cool-white f luorescent lamps (Ϸ25 mol⅐m Ϫ2 ⅐s Ϫ1 ) for various times.…”

“…Total RNA was isolated from Arabidopsis plants (13) and Northern transfers prepared and hybridized as described (22), except that high-stringency wash conditions were at 50ЊC in 0.1ϫ SSPE (1ϫ SSPE is 3.6 M NaCl͞20 mM EDTA͞0.2 M Na 2 HPO 4 , pH 7.7)͞0.5% SDS. Total Arabidopsis DNA was isolated (23) and transferred to nylon membranes (Micron Separations, Westboro, MA) as described (21).…”

Functionality of soybean CBF/DREB1 transcription factors

“…In the field, little growth occurs at temperatures below 6-7 °C [5], and cool temperatures at the end of the growing season are a major limiting factor in soybean yield and production [6]. Unlike soybean, Arabidopsis thaliana is able to cold acclimate and thus survive under severe cold-stress conditions; e.g., -8 to 10 °C [7,8]. In Arabidopsis, the C-repeat response element binding factors (CBFs) play a key, though not exclusive role [9,10], as positive regulators in an ABA-independent cold responsive pathway functioning to up-regulate many cold-regulated genes and thereby are critical contributors to cold/freezing tolerance [11].…”

“…Transgenic sweet potato plants expressing SCOF-1 also showed increased low temperature stress tolerance [31]. Despite the presence of SCOF-1 and CBF-like DREB1 transcription factors, soybean is cold-intolerant [7,8,32]; genes homologous to key Arabidopsis cold responsive genes, such as vegetative dehydrins and ADH, are not accumulated in response to cold stress [33,34].…”

A Lipidomic Approach to Identify Cold-Induced Changes in Arabidopsis Membrane Lipid Composition

“…Cold acclimation, or the development of tolerance to freezing by exposure to cold, but non-freezing, temperature, is a capability of many plants originating in temperate climates. Cold acclimation of Arabidopsis (Columbia accession) for 1 day or more decreases the lethal temperature from approximately -2°C to -8°C (1,2).…”