Development Of Cold Tolerance Research Articles

Integrated Transcriptomic and Proteomic Analysis Reveals Molecular Mechanisms of the Cold Stress Response during the Overwintering Period in Blueberries (Vaccinium spp.).

In China, the Liaodong Peninsula is an important growing area for blueberries because of the high organic matter content in the soil, the abundance of light, and the large temperature difference between day and night. However, the low temperature and relative humidity of the air during the winter and early spring in the Liaodong Peninsula are the main reasons for the damage to blueberry plants. Here, we documented the transcriptome and proteome dynamics in response to cold stress in three blueberry cultivars ('Northland', 'Bluecrop', and 'Berkeley'). Functional enrichment analysis indicated that many differentially expressed genes (DEGs) and differentially abundant proteins (DAPs) were mainly involved in the pathways of protein processing in the endoplasmic reticulum, the glutathione metabolism pathway, and ribosomes. We identified 12,747 transcription factors (TFs) distributed in 20 families. Based on our findings, we speculated that cold tolerance development was caused by the expression of calcium-related genes (CDPKs and CMLs), glutathione proteins, and TFs (NAC, WRKY, and ERF). Our investigation found that three cultivars experienced cold damage when exposed to temperatures between -9 °C and -15 °C in the field. Therefore, the cold resistance of blueberries during overwintering should not only resist the influence of low temperatures but also complex environmental factors such as strong winds and low relative humidity in the air. The order of cold resistance strength in the three blueberry cultivars was 'Berkeley', 'Bluecrop', and 'Northland'. These results provide a comprehensive profile of the response to cold stress, which has the potential to be used as a selection marker for programs to improve cold tolerance in blueberries.

Fall acclimation and spring deacclimation of root cold tolerance for two perennial asters1

Snow is an important temperature insulator for overwintering plants, and as the depth and duration of snowpack decreases with warmer weather and the frequency of extreme climate events increases, belowground tissues may be exposed to colder temperatures. Determining the cold tolerance of overwintering plant tissues for native species could help predict species persistence following winter climate change, yet most plant cold tolerance studies are about agricultural crop species, woody plants, or aboveground tissues. Also, plants can acclimate and deacclimate to winter so measuring cold tolerance across seasons provides a more accurate assessment of a species susceptibility to winter climate change. Here, we measure root cold tolerance of two native perennial grassland forbs (Solidago rigida and Silphium integrifolium) in a restored prairie across time to examine cold acclimation and deacclimation to seasonal temperature changes. Average root cold tolerance varied between the two species. Over time, the roots of S. rigida predictably gained cold tolerance as fall progressed and lost cold tolerance in spring. However, roots of S. integrifolium had variable cold tolerance across both seasons. The differences in cold tolerance development between grassland forb species may be a contributing factor explaining species persistence under continued winter climate change. Further research on the cold tolerance of native plant species and belowground tissues is needed to predict the response of temperate plant species and communities to winter climate change.

Relationship between Polyamines and Other Cold‐induced Response Mechanisms in Different Cereal Species

AbstractTo find a connection between polyamines and various protective effectors involved in the development of cold tolerance, eight different cereal genotypes, including wheat, barley and oat species, were investigated during the acclimation phase to low temperature. Exposure to low temperature induced different changes in the levels of polyamines, and other signalling molecules, such as salicylic acid and abscisic acid, and of other protective compounds, namely flavonols, sugars and antioxidant enzyme activity, and in the lipid composition of certain membrane factions. The most remarkable differences were observed in the oat varieties compared to the other cereal genotypes, which was manifested in the lack of spermidine accumulation and of decrease in trans‐Δ3‐hexadecanoic acid content, in lower initial and not cold‐inducible abscisic acid content and guaiacol peroxidase activity after cold treatment. Correlation analysis revealed that spermidine shows strong positive relationship with flavonols, abscisic acid and ascorbate peroxidase, while was in negative relationship with trans‐Δ3‐hexadecanoic acid. These results suggest that spermidine may have a crucial role in the cold acclimation signalling processes in cereals.

Role of phytochrome B in the development of cold tolerance in cucumber plants under light and in darkness

Cold tolerance of cucumber (Cucumis sativus L.) seedlings was investigated using wild-type plants and the phytochrome B-deficient mutant (lh-mutant). Plants were subjected for 6 days to intermittent short-term cooling (12°C for 2 h per day) and to continuous chilling under conditions of 16-h photoperiod (day/night = 16/8 h) and permanent illumination. “Dehardening” process was initiated by the transfer of plants to either light or dark conditions at 23°C. It was concluded that phytochrome B participates in the development of cold tolerance in cucumber plants under stress conditions, i.e., under short-term intermittent chilling at nights and during dehardening in continuous darkness.

The role of carbohydrates in the responses of chilling-sensitive plants to short- and long-term low-temperature treatments

The content of particular components of water-soluble carbohydrates and cold tolerance of cucumber (Cucumis sativus L.) cotyledonary leaves were studied at early developmental stages in dynamics during 6-day-long treatment with a temperature reduced to 12°C at two regimes: short-term cooling (2 h in the end of the night period, DROP) or permanent low-temperature treatment (PLT). PLT cucumber plants were characterized by the accumulation of oligosaccharides, whereas DROP plants contained increased amounts of glucose, fructose, and raffinose, indicating their higher metabolic status. When changes in carbohydrate fractions were compared with the dynamics of cold tolerance, it was found that these changes were synchronous in PLT plants but asynchronous for glucose and oligosaccharides in DROP plants. We suppose that, in cotyledonary leaves of DROP plants, two pools of sugars are produced; one of them used for tolerance development and another one — in active metabolism. This provides for the combination of activated metabolism and high cold tolerance of these plants. In PLT plants, all components of water-soluble carbohydrates are involved in cold tolerance development.

Cold tolerance and trehalose accumulation in overwintering larvae of the codling moth, Cydia pomonella (Lepidoptera: Tortricidae)

Seasonal variations in the supercooling point, survival at low temperatures and sugar content were studied in field-collected codling moth larvae. The supercooling point of field-collected larvae decreased significantly from a mean value of -13.4°C in August 2004 (feeding larvae) to -22.0°C in December 2004 (overwintering larvae). Survival at -20°C/24 h was 0% during early autumn, whereas it increased to approximately 60% during winter. The survival at low temperature was well correlated with the supercooling point. The supercooling point of the diapause destined larvae decreased from -16.9 to -19.7°C between September and October as the larvae left the food source and spun a cocoon. For early-diapause larvae, exposure to 5°C/30 days has an additional effect and decreased the supercooling point from -19.7 to -21.3°C. One-month exposure of overwintering larvae to 5°C led to a mortality of 23% in early diapause larvae, while only 4% of diapause larvae died after acclimation. Overwintering larvae accumulated trehalose during winter. There was approximately a threefold increase in trehalose content between larvae at the onset of diapause (5.1 mg/g fresh weight) and larvae in a fully developed diapause (18.4 mg/g fresh weight) collected in January. Trehalose content was correlated with supercooling capacity, survival at low temperatures and chilling tolerance, suggesting that trehalose may play some role in the development of cold tolerance in this species.

Identification of genes associated with cold acclimation in blueberry ( Vaccinium corymbosum L.) using a subtractive hybridization approach

Enhanced cold tolerance, including tolerance to winter freezing and spring frosts, is needed for genetic improvement of current highbush blueberry ( Vaccinium corymbosum L.) cultivars. To gain a better understanding of changes in gene expression associated with development of cold tolerance in blueberry and other woody perennials, forward and reverse subtracted cDNA libraries were prepared in such a way to enrich for transcripts that are expressed at higher levels in dormant blueberry flower buds at 400 h and at 0 h of low temperature exposure, respectively. Of the clones picked and single-pass sequenced, 503 clones from the forward subtracted library and 167 clones from the reverse subtracted library had inserts and yielded high quality sequences; and of these, 291 (57.9%) and 51 (31.0%), respectively, were assigned putative identities from BLAST searches of GenBank. From contig analyses to cluster genes of like or identical sequences, 275 unigenes (unique clones) from the forward subtracted library and 99 unigenes from the reverse subtracted library were obtained. Many interesting cold and light-stress related genes were identified from the forward subtracted library and several drought-stress related genes were identified from the reverse subtracted library. Many genes, not previously characterized from blueberry or other woody perennials, encoding putative transcription factors and proteins related to signal transduction were identified from both the forward and reverse subtracted libraries. Eleven genes of interest (six from the forward subtracted library and five from the reverse subtracted library) were selected and their expression was analyzed in floral buds by quantitative real-time RT-PCR over a time course from ∼0 to 1200 h of low temperature exposure. Expression profiles validated the quality of the libraries.

Induction of chilling tolerance in cucumber (Cucumis sativus) seedlings by endogenous and applied ethanol

Five‐day‐old etiolated cucumber (Cucumis sativus L.) seedlings cv. Marketmore held at 2°C for 72 h developed chilling injury, resulting in desiccation and collapse of the hypocotyl tissue and eventual plant death. Hypoxia‐induced accumulation of ethanol and acetaldehyde led to tolerance of subsequent chilling, as evidenced by continued hypocotyl growth and freedom from injury. Attenuated accumulation of volatiles by applied bisulfite reduced the development of hypoxia‐induced chilling tolerance in seedlings. In seedlings held in normoxia cold tolerance was induced by applied ethanol vapors, whereas acetaldehyde had a marginal effect, suggesting that hypoxia‐induced cold tolerance may arise from the accumulation and activity of ethanol. Cold tolerance was also induced by exposure of seedlings to volatile anesthetics including n‐propanol, n‐butanol, chloroform and halothane, suggesting that ethanol activity may result from fluidization of membrane lipids. This view is consistent with results which showed that ethanol activity was not associated with lipid metabolism. However, development of cold tolerance in ethanol‐enriched tissues was time dependent, indicating that ethanol activity probably also entails biosynthetic event(s).

INDUCTION OF CHILLING-TOLERANCE IN CUCUMBER (CUCUMIS SATIVUS L.) SEEDLINGS BY ENDOGENOUS AND APPLIED ETHANOL

Five-day-old etiolated cucumber (Cucumis sativus L. cv. Marketmore) seedlings held at 2C for 72 hours develop chilling injury resulting in desiccation and collapse of the hypocotyl tissues and eventual plant death. Hypoxia-induced accumulation of ethanol and acetaldehyde led to tolerance to subsequent chilling as evidenced by continued hypocotyl growth and freedom from injury. Arrest of volatile accumulation by applied bisulfite negated the development of hypoxia-induced chilling tolerance in seedlings. In seedlings held in normoxia, cold tolerance was induced by applied ethanol vapors, whereas acetaldehyde had a marginal effect, suggesting that hypoxia-induced cold tolerance may arise from the accumulation and activity of ethanol. Cold tolerance was induced by exposure to gaseous n-propanol and n-butanol vapors and other volatile anesthetics, including chloroform and halothane, indicating that ethanol activity may stem in part from an anesthetic effect that causes disorder of membrane lipids. However, development of cold tolerance in ethanol-enriched tissues was time-dependent, suggesting an association with biosynthetic event(s). Ethanol did not change the fatty acid composition in cucumber hypocotyl membranes.

Development of Cold Tolerance in White Clover (Trifolium repensL.) in Relation to Carbohydrate and Free Amino Acid Content

Abstract Development of cold tolerance in white clover (Trifolium repens L.) genotypes originating from various parts of Norway and grown outdoors at Tromso, latitude 69°39′N, has been studied. Stolon samples for an artificial freezing test and for chemical analysis were collected three times during the autumn. Generally, the most northern genotypes were more cold tolerant than the southern ones. Cold tolerance increased significantly from September to November in all genotypes. Content of dry matter, soluble carbohydrates, sucrose and proline in stolons increased during the hardening process. These changes were similar in both northern and southern genotypes of white clover.

NITROGEN, PHOSPHORUS AND MOISTURE EFFECTS ON ACCLIMATION OF WINTER PEAS

Increased residual soil nitrogen and compaction-related waterlogging problems may relate to observed reductions in Austrian winter pea (Pisum sativum subsp. arvense (L.) Poir.) winter survival by influencing cold tolerance development. This study examines the influence of supplemental nitrogen and phosphorus on the cold tolerance of field acclimated Melrose Austrian winter peas. In 1981, on a poorly drained site, nitrogen rates of 34–101 kg N ha−1 increased LT50 to −6.9 from −7.4 °C for unfertilized peas through wk 7 of acclimation. Average winter pea LT50 after freezing at −4, −7 and −10 °C peaked at −7.7 °C at 7 wk of acclimation. LT50 was correlated (r = 0.85**) with declining epicotyl moisture (mg g−1). Survival declined from 51 to 8% between 7 and 9 wk of acclimation, corresponding to a threefold increase in average daily precipitation and waterlogged conditions. Tissue water levels (mg H2O epicotyl−1) between 7 and 9 wk of acclimation were correlated with LT50 (r = 0.64*). Winter peas cold tolerance peaked at −8.7 °C 9 wk after planting in 1982. High N rates reduced survival 16%, but did not influence LT50. Increased epicotyl N was correlated with survival (r = − 0.83**). Percent epicotyl moisture content correlated with LT50 (r = 0.70*) through 9 wk of acclimation. Phosphorus did not influence LT50 in either year.Key words: Pisum sativum subsp. arvense (L.) Poir., poor drainage, cold tolerance, plant water status, residual nutrient levels, pea (Austrian winter)

Centipedegrass Cold Tolerance as Affected by Environmental Factors1

AbstractCentipedegrass [Eremochloa ophiuroides (Munro) Hack.] is an excellent lawn grass throughout much of the lower South. However, lack of cold tolerance has limited its use. An environmental chamber study was conducted to determine: 1) the rate at which cold tolerance is developed and lost in centipedegrass and 2) the effect of photoperiod and temperature on cold tolerance development in an effort to identify factors or conditions contributing to cold damage in centipedegrass.Development of cold tolerance was determined by cold hardening (16 C day, 4 C night, 12‐hour photoperiod) centipedegrass for 0, 10, 20, 30, or 40 days. Loss of cold tolerance was determined by transferring cold hardened plants to favorable growing conditions for 0, 2, 4, or 6 days. In the photoperiod‐temperature study, plants received 8, 12, or 16 hours of light at 23 C followed by either a 23 C or 4 C night. In each study, following a 4‐hour exposure at −7 C, plants were returned to favorable growing conditions. Foliage kill and survival were determined after 7 and 21 days, respectively.Hardening periods greater than 10 days caused no increase in survival and only a slight reduction in top‐kill. Cold tolerance was lost rapidly; i.e., cold hardened plants exposed to 2 days of favorable growing conditions showed the same injury as unhardened controls. Photoperiod alone did not affect cold tolerance; however, a combination of a low night temperature (4 C) and short‐photoperiod (8 hours of light) gave maximum cold tolerance. In conclusion, centipedegrass acquires and loses cold tolerance within a few days, an important consideration in the lower South where winters are often interrupted by periods of warm weather.

Electrophoretic studies of the relationship of peroxidases, polyphenol oxidase, and indoleacetic acid oxidase to cold tolerance of alfalfa

Two cultivars of alfalfa ( Medicago sativa L.), cold-tolerant Vernal and cold-sensitive Sonora, were grown under summer, winter, and dehardening environments to investigate the relationship of soluble proteins and enzyme activity and solubility characteristics to cold tolerance. Evaluations of cold-tolerance levels developed in crown and root samples were compared with results of soluble protein analyses and were in agreement with previously reported observations. Soluble protein content was associated with increases in cold tolerance and related to the environment from which samples were obtained; however, the degree of protein differences within samples of the same cultivar as well as between the two cultivars seemed to be influenced by the type of extractant used. Polyacrylamide disc gel electrophoresis of the extracted soluble proteins was performed on the basis of equal dry weights and equal quantities of protein. Amido black straining of gels indicated mainly quantitative changes and slight qualitative differences in component bands influenced by environment and extractant. Gels assayed for peroxidase, polyphenol oxidase, and indoleacetic acid oxidase enzymes exhibited mainly quantitative differences in constitutive isoenzyme components of both cultivars which were associated with environmental changes. Enzyme activities generally increased in winter, as cold tolerance and soluble protein content increased, and decreased during dehardening. The few qualitative differences in isoenzyme bands that were detected, appeared to be influenced by cultivar, environment, extractant, or substrate specificity differences. Variation in isoenzyme components between cultivars was maximum in summer samples, and minimum in winter samples, suggesting that overall reaction rates or activities of individual isoenzymes, preceding or during hardening, could be a limiting factor in cold-tolerance development.

Acquisition and loss of cold-tolerance in adult barnacles (Balanus balanoides) kept under laboratory conditions

In the laboratory, Balanus balanoides (L.) barnacles maintained without food at 5°C over the winter to summer period remained cold-tolerant. Winter animals maintained at 5°C and fed Artemia nauplii under a controlled light-dark regime until mid-summer lost this cold-tolerance. Summer animals, maintained without food at 5° or 15°C until midwinter, became cold-tolerant. Summer and winter animals subjected to increased (or decreased) ambient salinity for 48 h showed a small decrease (or increase) in their lower median lethal temperature (MLT—defined as the temperature at which 50% of the animals die after 18 h exposure to air). Summer animals subjected to desiccation for 48 h also showed a small decrease in their lower MLT. It is concluded that the seasonal changes in cold-tolerance of adult barnacles are probably induced by a combination of environmental factors including food availability, light intensity, day-length and changes in ambient sea-water temperatures. Development of cold-tolerance in the winter did not depend upon fertilisation. Changes in intra-cellular solute concentration which accompany adaptation to changes in ambient salinity or desiccation do not appear to be related to the seasonal changes in cold-tolerance.