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Donato Chiatante Gabriella S. Scippa Lucia Maiuro Elisabetta Onelli Giuseppe Patrignani 《Plant biosystems》2013,147(1):35-47
ABSTRACT To understand the mechanisms which enable the nucleus to function under low water potential, the morphology and biochemistry of potato cell nuclei were studied. Conformational modifications were observed in the chromatin of nuclei of cells growing under low water potential. These modifications include a higher number of heterochromatic centres, enlargement of the nuclear diameter, and a different accessibility of DNA to the action of restriction enzymes. Biochemical analyses showed that these chromatin modifications may coincide with quantitative and qualitative variations of several nuclear proteins, some of which may belong to the dehydrin family. We especially focussed our attention on a 45-kDa protein that is heat-stable and is recognised by an antibody raised against the conserved domain of dehydrins. The survival of potato cells in an environment where water availability is low may depend on several simultaneous events regarding the nucleus. The accumulation in the nucleus of specific proteins such as dehydrins could be required to stabilise the chromatin by means of their molecule-salvation action. Further studies are in progress to check whether or not variations in chromatin organisation may be one of the numerous traits that a cell must acquire to become water-stress resistant. 相似文献
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Hydrophilins from distant organisms can protect enzymatic activities from water limitation effects in vitro 总被引:2,自引:0,他引:2
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Seasonal patterns of dehydrins and 70-kDa heat-shock proteins in bark tissues of eight species of woody plants 总被引:6,自引:0,他引:6
Michael Wisniewski Timothy J. Close Timothy Artlip Rajeev Arora 《Physiologia plantarum》1996,96(3):496-505
Although considerable effort has been directed at identifying and understanding the function and regulation of stress-induced proteins in herbaceous plants, reports concerning woody plants are limited. Studies with herbaceous crops have revealed similarities in the types of proteins that accumulate in response to a wide array of abiotic stresses and hormonal cues such as the accumulation of abscisic acid. Many of the identified proteins appear to be related to dehydrins (the D-11 subgroup of late-embryogenesis-abundant proteins). The objective of the present study was to determine if seasonal induction of dehydrins is a common feature in woody plants and to see if seasonal patterns existed for other stress-induced proteins. Bark tissues from eight species of woody plants were collected monthly for a period of 1.5 years. The species included: peach (Prunus persica) cv. Loring; apple (Malus domestica) cv. Golden Delicious; thornless blackberry (Rubus sp.) cv. Chester; hybrid poplar (Populus nigra); weeping willow (Salix babylonica); flowering dogwood (Cornus florida); sassafras (Sassafras albidum); and black locust (Robinia pseudo-acacia). Immunoblots of bark proteins were probed with a polyclonal antibody recognizing a conserved region of dehydrin proteins, and monoclonal antibodies directed against members of the HS70 family of heat-shock proteins. Some proteins, immunologically related to dehydrins, appeared to be constitutive; however, distinct seasonal patterns associated with winter acclimation were also observed in all species. The molecular masses of these proteins varied widely, although similarities were observed in related species (willow and poplar). Identification of proteins using the monoclonal antibodies (HSP70, HSC70, BiP) was more definitive because of their inherent specificity, but seasonal patterns were more variable among the eight species examined. This study represents only a precursory examination of several proteins reported to be stress related in herbaceous plants, but the results indicate that these proteins are also common to woody plants and that further research to characterize their regulation and function in relation to stress adaptation and the perennial life cycle of woody plants is warranted. 相似文献
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Chill-responsive dehydrins in blueberry: Are they associated with cold hardiness or dormancy transitions? 总被引:6,自引:0,他引:6
To survive winters, woody perennials of temperate zones must enter into endodormancy. Resumption of spring growth requires sufficient exposure to low temperature (chill units, CUs) in winter (chilling requirement), which also plays a role in the development of cold hardiness (cold acclimation). Physiological studies on dormancy breaking have focused on identifying markers, such as appearance or disappearance of proteins in response to varying degrees of chill unit accumulation. However, whether these changes are associated with dormancy transitions or cold acclimation is not clear. In the present study, greenhouse-grown blueberry (Vaccinium section Cyanococcus) plants were used to address this question. Three blueberry cultivars, Bluecrop, Tifblue, and Gulfcoast having chilling requirement of approximately 1 200, 900 and 600 CUs, respectively, were first exposed to 4°C for long enough to provide chill units equivalent to one-half of their respective chilling requirement. This treatment was expected to result in cold acclimation. A fraction of plants was then subjected to a 15/12°C (light/dark) regime for 2 weeks, a treatment expected to be “dormancy-neutral” but cause deacclimation. Before and after each treatment, cold hardiness and dormancy status of floral buds were determined; proteins were extracted from the buds collected on the same sampling date, and separated by one-dimensional SDS-PAGE. Dehydrin-like proteins were identified by immunoblotting, using anti-dehydrin antiserum. Results indicate that the chilling treatment resulted in cold acclimation as indicated by increased bud hardiness in all three cultivars. Data also indicate a distinct accumulation of three dehydrin-like proteins of 65, 60, and 14 kDa during cold acclimation. The cold hardiness and levels of dehydrin proteins decreased during the exposure to 15/12°C for 2 weeks. Results also confirmed that this treatment had no negative effect on chill unit accumulation. Densitometric scans of protein gels indicated a close association between the abundance of dehydrins and degree of cold hardiness in these cultivars. In addition, levels of the dehydrin proteins and cold hardiness remained about the same between 100% and >100% satisfaction of chilling requirement. These results suggest that changes in dehydrin expression are more closely associated with cold hardiness than with dormancy transitions. 相似文献
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The wheat wcs120 gene family. A useful model to understand the molecular genetics of freezing tolerance in cereals 总被引:8,自引:0,他引:8
Winter, as compared with spring cereals, possess better acclimation mechanisms that allow them to overwinter and survive freezing temperatures. This difference is genetically programmed and involves a complex genetic system. To understand the nature of this system and its regulation by low temperature, genes associated with freezing tolerance in wheat ( Triticum aestivum L.) were identified and characterized. Among these, the wcs120 gene family encodes a group of proteins ranging in size from 12 to 200 kDa. As shown by biochemical, immunohistochemical, molecular and genetic analyses, this gene family is specific to the Poaceae, highly abundant and coordinately regulated by low temperature. Furthermore, accumulation of WCS protein is directly correlated with the development of freezing tolerance. These analyses also revealed a regulatory control of the vernalization process over low temperature gene expression in winter cereals. Recent studies suggest that the molecular mechanisms controlling the expression of these genes involve negative regulatory factors that are modulated by phosphorylation. 相似文献
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Sharall R. Palmer Ray De Villa Steffen P. Graether 《Protein science : a publication of the Protein Society》2019,28(8):1448-1459
Intrinsically disordered stress proteins have been shown to act as chaperones, protecting proteins from damage caused by stresses such as freezing and thawing. Dehydration proteins (dehydrins) are intrinsically disordered stress proteins that are found in almost all land plants. They consist of a variable number of the short, semi‐conserved, Y‐, S‐, and K‐segments, with longer stretches of poorly conserved sequences in between. Previous studies have provided conflicting views on the details of the dehydrin cryoprotective mechanism of enzymes. Experiments with polyethylene glycol (PEG) have shown that PEG cryoprotective efficiency is the same as dehydrins of the same hydrodynamic radius, suggesting that the protein's disordered and polar nature is important, rather than the specific order of the residues. To further elucidate the mechanism, we created scrambled variants of the wild grape dehydrins K2 and YSK2 and tested their ability to protect lactate dehydrogenase and yeast frataxin homolog‐1 from freeze/thaw damage. The results show that for preventing aggregation, it is the sequence composition and the size of the dehydrin that is the most important factor in protection, while for freeze/thaw damage causing loss of secondary structure, it is the sequence composition that is most significant. 相似文献
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