Dehydrin Expression Research Articles

Expression of KS-type dehydrins is primarily regulated by factors related to organ type and leaf developmental stage during vegetative growth.

The expression of a gene, designated as DHN10, was analyzed at the protein level in two Solanum species. The DHN10 protein displays some consensus amino acid sequences of dehydrins, termed K- and S-segments. Unlike most dehydrins, both segments occur only in single copies in the DHN10 sequence and the S-segment is at a C-terminal position. Database searches revealed that KS-type dehydrins constitute a specific subclass distributed in dicotyledons and monocotyledons. In Solanum tuberosum L. plants, a high DHN10 abundance was observed under control conditions, particularly in flowers, stems, tubers and young developing leaves. In other Solanaceae and in barley ( Hordeum vulgare L.), the amount of DHN10 was much more elevated in young leaves than in old leaves. DHN10 abundance was investigated in two Solanum species subjected to low temperature or to drought. Under stress conditions, we observed substantially higher protein levels only in mature expanded leaves. These findings clearly indicate that KS-type dehydrins are present at a high level in the absence of stress during vegetative growth and that their expression is primarily regulated by factors related to organ type and to leaf development stage. A potential role for the DHN10 dehydrin during plant development and in tolerance to environmental stress is discussed.

Identification of a Chloroplast Dehydrin in Leaves of Mature Plants

Several types of proteins are known to accumulate as a result of dehydration stress in plants, and many of these are thought to serve a protective function. This includes the dehydrin family of proteins, which accumulate in cells in response to drought, low temperatures, or salinity and in embryo tissues during the maturation phase of seed development, when the seed is losing water in preparation for dormancy. Many studies to date have concentrated on the expression, localization, and function of dehydrins in seed tissues. Our study provides some of the first evidence for a chloroplast‐localized dehydrin by using cell fractionation combined with immunofluorescence and immunogold electron microscopy to determine dehydrin location in mature leaf tissues of Pisum sativum and Zea mays. This article also documents constitutive expression of the chloroplast dehydrin as well as expression during different dehydrative stresses. The chloroplast‐dehydrin expression pattern differs from most other dehydrins studied to date and suggests a role in basic cell metabolism for this particular dehydrin.

Dehydrin Expression and Drought Tolerance in Seven Wheat Cultivars

The winter wheat (Triticum aestivum L.) producing region of the U.S. Pacific Northwest (PNW) is subject to periods of water deficit during sowing and grain filling. Improving the genetic adaptation of wheat to drought stress represents one of the main objectives of regional breeding programs. One biochemical response to dehydrative stress is the accumulation of a family of proteins called dehydrins, which are believed to protect membranes and macromolecules against denaturation. Although previous studies demonstrated the accumulation of dehydrins in drought-stressed wheat, little was known about the relation of dehydrin expression to acquisition of drought tolerance in specific varieties adapted to the PNW. We characterized dehydrin accumulation during the exposure of seven cultivars ('Connie', 'Gene', 'TAM105', 'Rod', 'Hiller', 'Rhode', and 'Stephens') to progressive drought stress in four separate experiments. The objective was to identify differences in the nature or timing of dehydrin expression in these cultivars and to learn whether dehydrin expression was associated with the acquisition of stress tolerance during seedling development. Expression of a 24-kDa dehydrin was observed in Connie, TAM105, and Gene after 4 d of stress and at subsequent sampling dates while no dehydrins were detected in nonstress control plants. Dehydrin expression was significantly delayed in the remaining cultivars. The presence of this dehydrin was related to acquisition of drought tolerance characterized by a greater maintenance of shoot dry matter production in Connie, TAM105, and Gene. Although the role of these proteins remains unknown, their association with stress tolerance suggests that dehydrins might be used to improve the adaptation to drought.

Dehydrin Expression and Drought Tolerance in Seven Wheat Cultivars

The winter wheat (Triticum aestivum L.) producing region of the U.S. Pacific Northwest (PNW) is subject to periods of water deficit during sowing and grain filling. Improving the genetic adaptation of wheat to drought stress represents one of the main objectives of regional breeding programs. One biochemical response to dehydrative stress is the accumulation of a family of proteins called dehydrins, which are believed to protect membranes and macromolecules against denaturation. Although previous studies demonstrated the accumulation of dehydrins in drought-stressed wheat, little was known about the relation of dehydrin expression to acquisition of drought tolerance in specific varieties adapted to the PNW. We characterized dehydrin accumulation during the exposure of seven cultivars (‘Connie’, ‘Gene’, ‘TAM105’, ‘Rod’, ‘Hiller’, ‘Rhode’, and ‘Stephens’) to progressive drought stress in four separate experiments. The objective was to identify differences in the nature or timing of dehydrin expression in these cultivars and to learn whether dehydrin expression was associated with the acquisition of stress tolerance during seedling development. Expression of a 24-kDa dehydrin was observed in Connie, TAM105, and Gene after 4 d of stress and at subsequent sampling dates while no dehydrins were detected in nonstress control plants. Dehydrin expression was significantly delayed in the remaining cultivars. The presence of this dehydrin was related to acquisition of drought tolerance characterized by a greater maintenance of shoot dry matter production in Connie, TAM105, and Gene. Although the role of these proteins remains unknown, their association with stress tolerance suggests that dehydrins might be used to improve the adaptation to drought.

Drought survival, summer dormancy and dehydrin accumulation in contrasting cultivars of Dactylis glomerata.

To study survival under prolonged and severe drought in the perennial grass Dactylis glomerata we compared dormant, resistant and sensitive cultivars (cvs.) in both field and glasshouse experiments. Water status, membrane stability and expression of dehydrins were assessed in the immature leaf bases, which are the last surviving organs. Analysis of leaf elongation and senescence of aerial tissues showed that dormancy was exhibited by the potentially dormant cultivar (cv.) only in the field. This cultivar exhibited a high survival rate, similar levels of dehydration and expression of a low-molecular weight (22-24 kDa) dehydrin in both drought and irrigated plants, whether fully dormant or not. At the same level of soil water deficit, there were no differences between the non-dormant drought resistant and drought sensitive cultivars in plant water status and membrane stability. However, the accumulation of dehydrins as drought progressed was markedly different between these cultivars and was associated with their contrasting survival. The possible role of the major low-molecular dehydrins in maintenance of cell integrity under dehydration is discussed with reference to both summer dormancy and survival under severe drought.

Profiles of Trinexapac-ethyl- and ABA-induced heat-stable proteins in embryonic axes of wheat seeds

Treatment of plants with abscisic acid (ABA) can enhance resistance to environmental stresses in general and to preharvest sprouting in particular. Inhibitors of gibberellin (GA) synthesis have been reported to enhance the metabolic activity or effectiveness of ABA. Wheat seeds(Triticum aestivum L., cv. Bet Hashita) were soaked for 2 h in100 μm ABA, in 1250 ppm trinexapac-ethyl (TE, anacylcyclohexanedione-based GA synthesis inhibitor), or in a combination of the two. After drying, seeds were imbibed 24 h in water and the protein in heat-stable extracts from embryos was examined. Treatment with ABA alone increased expression of dehydrin and of a 37 kDa protein. Treatment with TE more than doubled protein concentration in the embryo and enhanced expression of dehydrin and of proteins weighing 37, 20, and15 kDa. Combined treatments of TE and ABA led to enhanced expression of dehydrin and of a 15 kDa protein.

Wheat dehydrin accumulation in response to drought stress during anthesis.

The winter wheat (Triticum aestivum L.) producing region of the US Pacific Northwest (PNW) is often subject to water deficits at sowing and during grain filling. Improved genetic adaptation of wheat cultivars to drought stress is one objective of breeding efforts in the region. Consequently, there is interest in identifying molecular markers associated with drought tolerance. Dehydrins, a family of proteins that accumulate in response to dehydrative stress, may provide a suitable marker for use in breeding programs. Seven cultivars (Connie, Gene, TAM105, Rod, Hiller, Rhode and Stephens) were evaluated in two experiments in which dehydrin accumulation and their association to stress tolerance during grain filling were characterized during progressive drought stress. A24-kDa dehydrin was present in leaves at each sampling date in all seven cultivars. Quantitative differences in accumulation of this protein were observed between cultivars on the third sampling date (4 d of stress). This differential accumulation was associated with stress tolerance characterized by a lower yield reduction and a lowered rate of decrease in leaf water potential in Connie, TAM105 and Gene. In contrast to leaves, an increased number of dehydrins were observed in grains under stress and non-stress treatments. Despite the number of dehydrins detected, there was no apparent association between drought stress and dehydrin expression in grains. Although the specific role of these proteins remains unknown, their association with stress tolerance suggests that dehydrins have utility in improving adaptation to drought and as markers for drought tolerance.

Changes in dehydrin expression associated with cold, ABA and PEG treatments in blueberry cell cultures

Cell cultures of highbush blueberry cultivar ‘Gulfcoast’ ( Vaccinium corymbosum L. x Vaccinium darrowi Camp) were used to determine if tissue cultures could be used as a surrogate for whole plants in studying dehydrin expression. Cell clusters in liquid medium were subjected to treatments known to induce dehydrins in whole plants, and dehydrin protein and RNA levels were monitored. Two dehydrins of 65 and 30 kDa were detected with a polyclonal antibody raised against the 65 kDa dehydrin of blueberry. Using a full-length cDNA clone of blueberry dehydrin 1 as a probe, one mRNA of 0.75 kb, an appropriate size to encode the 30 kDa dehydrin, was detected on RNA blots. When cells were grown at 4 °C, abundance of the 30 kDa dehydrin increased, but the 65 kDa dehydrin did not. Level of the 0.75 kb message increased temporarily then decreased with cold treatment. Disparities between protein and transcript levels suggested that post-transcriptional mechanisms were involved in regulation of dehydrin expression. Some of the abscisic acid (ABA) concentrations tested induced expression of both dehydrins. Polyethylene glycol in the cultures repressed expression of both dehydrins and of the 0.75 kb mRNA. Results obtained from cell culture differed in too many ways from those on whole plants to make cell culture suitable for studying dehydrin expression in blueberry.

Drought survival and dehydration tolerance in Dactylis glomerata and Poa bulbosa

To analyse the contribution of dormancy and dehydration tolerance to drought survival of perennial grasses, we compared Poa bulbosa L., which is classified as a resurrection plant, with one of the most drought resistant cultivars of MediterraneanDactylis glomerata L. Comparing periods when dormancy was induced in Poa (summer) and not induced (winter), we aimed to ascertain the presence of differential plant responses between dormancy and dehydration tolerance and to characterise water status, sugar and dehydrin accumulation in surviving organs of Poa and Dactylis, in relation to their ability to survive intense drought. Irrespective of the dormancy status of Poa, the bulbs of this species had a final water content lower than 10% and survived an extreme drought. This could be associated with the accumulation of sucrose and the expression of a high number (>10) of dehydrins that peaked when the water content of the bulbs fell below 50%, whether this dehydration was due to dormancy induction or increasing soil water deficit. The independence of dormancy to dehydration tolerance was reinforced by the expression of a specific dehydrin (approx. 28 kDa) found only in irrigated, but dormant, tissues of Poa. The Dactylis exhibited contrasting survival between experiments (46 and 0% after a summer and winter drought, respectively). The mortality was associated with a significantly higher rate of decrease of the membrane stability of leaf bases of Dactylis in winter and with barely detectable amounts of sucrose contents in droughted roots. However, neither the water-soluble carbohydrate concentration in leaf bases nor the overall accumulation of dehydrins could be related to the contrasting survival of this Dactylis between the two seasons. Since in seeds of Poa and Dactylis, the accumulation of dehydrins was comparable with that found in droughted aerial tissues of the same species, the expression of these proteins must interact with other mechanisms to confer dehydration tolerance.

A 25-kDa dehydrin associated with genotype- and age-dependent leaf freezing-tolerance in Rhododendron: a genetic marker for cold hardiness?

Dehydrins are plant proteins that may play a critical role in stabilizing cell functions during freezing and other dehydrative stresses. This study examines whether dehydrin expression in leaves is associated with varying levels of freezing-tolerance among F2 segregants, species, and cultivars of evergreen Rhododendron. Experiments were also conducted to determine whether physiological and chronological aging affects freezing-tolerance and dehydrin accumulation in Rhododendron leaf tissues. Our results indicate that in cold-acclimated F2 populations, levels of a 25-kDa dehydrin were closely associated with differences in leaf freezing-tolerance (LFT) among segregants. Studies of wild and cultivated plants indicated that LFT increased with both chronological age and developmental phase-change (juvenile to mature plants) and that this trend was accompanied by increased accumulation of the 25-kDa dehydrin. It is suggested that presence or absence of the 25-kDa dehydrin could serve as a genetic marker to distinguish between super cold-hardy and less cold-hardy rhododendron genotypes. Similarly, the relative level of this protein within a genotype can serve as a physiological indicator of freezing-tolerance status under a range of phenological (acclimation) or developmental (age) conditions.

Complementary DNA cloning, sequencing and expression of an unusual dehydrin from blueberry floral buds

Levels of three major dehydrins of 65, 60, and 14 kDa have been observed to increase in blueberry (Vaccinium smpp.) floral buds during chill unit accumulation and cold acclimation and decrease during deacclimation and resumption of growth. Indeed, levels of the 65‐, 60‐, and 14‐kDa dehydrins increase such that they become the most predominant proteins visible on sodium dodecyl sulfate (SDS)‐polyacrylamide gels. The peptide sequence information from the 65‐ and 60‐kDa dehydrins was used to synthesize degenerate DNA primers for amplification of a part of the gene(s) encoding the dehydrins. One pair of primers amplified a 174‐bp fragment. The 174‐bp fragment was used to screen a cDNA library (prepared from RNA from cold‐acclimated blueberry floral buds) and resulted in the isolation of a clone with a 2.0‐kb insert. The cDNA was sequenced and found to be a full‐length clone encoding a K5‐type dehydrin (5 K boxes). Five high‐confidence peptide sequences, ranging from 9 to 25 amino acids long, obtained from the 60‐kDa dehydrin exactly matched sequences encoded within the cDNA clone. Furthermore, amino acid composition of the 60‐kDa dehydrin agreed well with the expected amino acid composition based on the cDNA sequence. However, the DNA sequence and coupled in vitro transcription/translation reactions of the cDNA clone indicated that it encodes a dehydrin with a native molecular mass of ∼40 kDa instead of 60 kDa. Experiments to determine if the dehydrins undergo post‐translational modifications revealed that the 65‐ and 60‐kDa dehydrins are glycosylated. Thus, our results indicate that the 2.0‐kb dehydrin cDNA encodes the native version of the 60‐kDa dehydrin. The dehydrin cDNA hybridized on RNA blots to two chilling/cold‐responsive messages of 2.0 and 0.5 kb. Both the 2.0‐ and 0.5‐kb messages increased to higher levels more quickly in the cold‐hardy cultivar Bluecrop than in the less hardy cultivar Tifblue. In addition, the 0.5‐kb message remained at a higher level longer in Bluecrop than in Tifblue.

094 Cloning Blueberry Dehydrins and Their Expression under Stress Conditions

Dehydrins are major plant proteins that increase with cold or drought. Using a previously identified 2.0-Kb blueberry dehydrin cDNA, additional dehydrin clones were isolated and characterized. Experiments were conducted to determine effect of drought and cold treatment on dehydrin gene expression in several blueberry cultivars. Besides previously characterized 65, 60, and 14 kDa dehydrins in floral buds additional less abundant dehydrins were observed in stem and root tissues. The same major dehydrins were induced by both drought and cold stress but at different levels. Dehydrin expression was positively correlated with cold and drought tolerance. In addition, photoperiod was observed to affect dehydrin expression. Dehydrins were induced to higher level in cold treated plants kept in total dark than in plants kept at a short photoperiod of 10 hours of light/14 hours dark.

Characterization of an 80‐kDa dehydrin‐like protein in barley responsive to cold acclimation

Barley (Hordeum vulgare L.) exposed to low temperature increases its freezing tolerance. This increase has been associated with several metabolic changes caused by low temperature, including expression of dehydrins (DHN), a family of proteins induced by dehydration and cold acclimation. DHNs play an undetermined role in dehydration responses during freezing. We have studied the accumulation of an 80‐kDa DHN‐like protein (P‐80) in barley under cold acclimation 6/4°C (day/night), postulating that it is localized in tissues where primary ice nucleation occurs. P‐80 was absent in nonacclimated plants and was detectable after 48 h of cold acclimation, reaching a stable level after 6 days. P‐80 decreased when plants were returned to 20–25°C. Drought, ABA and high temperature did not increase the levels of P‐80, suggesting that its expression could be specifically regulated by cold. Immunolocalization by tissue printing and fresh cross sections of leaves showed the protein to be associated with vascular tissues and epidermis. The localization of P‐80 is consistent with our hypothesis because vascular tissue and the epidermis are preferential ice nucleation zones during the onset of freezing. The differential accumulation of P‐80 may have an adaptive value by participating in tolerance mechanisms during freeze‐induced dehydration.

Expression of Heat-stable and Putative Dehydrin Proteins during Nonacclimated and Cold-acclimated Conditions in Several Tuber-bearing Solanum Species

Recent studies suggest cold-regulated heat-stable proteins mitigate the potential damaging effects of low water activity associated with freezing. A proposed function of these proteins is stabilization of enzymes during exposure of plants to subzero temperatures. To test this hypothesis for tuber-bearing Solanum L. species we determined the quantitative expression of heat-stable proteins, the qualitative changes in dehydrin proteins, and the capacity of heat-stable proteins to cryoprotect a freeze-thaw labile enzyme lactate dehydrogenase (LDH). We used five tuber-bearing Solanum species (S. tuberosum L. `Red Pontiac', S. acaule Bitter, S. sanctae rosea Hawkes, S. commersonii Dunal, and S. cardiophyllum Bitter), which vary in nonacclimated relative freezing tolerance (NA RFT), acclimated relative freezing tolerance (AC RFT), and acclimation capacity (ACC). The protein fraction containing a mixture of heat-stable proteins demonstrated cryoprotective capacities greater or equal to other cryoprotective compounds (bovine serum albumin, polyethylene glycol, glycerol, and sucrose). Heat-stable proteins extracted from acclimated S. commersonii had superior cryoprotective capacity than those extracted from nonacclimated S. commersonii plants. Interestingly, in the presence of these proteins extracted from acclimated plants (in S. commersonii and S. sanctae rosea), LDH activity was elevated above that of unfrozen controls. No quantitative relationships were found between heat-stable protein concentration and NA RFT, AC RFT, or ACC among the five species. This was also true for dehydrin protein expression. Cold acclimation treatment resulted in increased dehydrin expression for acclimating and nonacclimating species. In three of the cold acclimating species (S. acaule, S. sanctae rosea, and S. commersonii), an increase in dehydrin expression may play a role in increased freezing tolerance during cold acclimation. In the cold sensitive, nonacclimating species (S. tuberosum and S. cardiophyllum), however, an increase in dehydrin level maybe related to the response of these species to changed (perhaps stressful) environment during cold treatment. By exploiting the genetic variation in NA RFT and ACC for five tuber-bearing species, we were able to gain new insight into the complexity of the relationship between heat-stable protein and cold response.

Freezing Tolerance in Rhododendron and Its Association with Dehydrin Expression

This study examines whether dehydrin expression in leaves is associated with varying levels of cold hardiness among evergreen rhododendrons. Initially, differences in leaf freezing tolerance (LFT) were determined within three groups of plants: 1) a cultivar group; `Chionoides' (CND), `Grumpy Yellow' (GY), and `Vulcan's Flame' (VF) 2) a segregating F2 population derived from a super coldhardy (R. catawbiense) × less-hardy (R. fortunei) cross, and 3) juvenile seedlings and mature plants of wild-collected R. maximum. LFTs in fully acclimated cultivars corresponded with their USDA hardiness zone ratings—CND (zone 4, –32 °C) GY (zone 7, –16 °C), and VF (zone 6, –19 °C). F2 segregation was characterized by a continuous, normal distribution of LFT values, with groups of progeny at the “tails” differing in their mean LFT by 20 °C. Juvenile seedlings of R. maximum exhibited LFTs that were 12 °C lower than LFTs from mature plants. Western blots of leaf proteins revealed a common 50-kDa dehydrin that accumulated during cold acclimation in all three cultivars and appeared to be quantitatively associated with LFTs. Isoelectric focusing of the 50-kDa Rhododendron dehydrin revealed two isoforms (pI 5.5 and 6.5). The more acidic isoform was detected only in the hardiest (CND) cultivar. Experiments are underway to examine qualitative and quantitative expression of dehydrins and its association with LFT in the segregating F2 population and in the group of R. maximum plants differing in physiological age.

Response of Dehydrins to Drought, Low Temperature, and ABA Treatment in Whole Plants and Cell Suspension Cultures of Blueberry

Previously, three dehydrins of 65, 60, and 14 kDa were identified as the predominant proteins present in cold-acclimated blueberry floral buds. Levels were shown to increase with cold acclimation and decrease with deacclimation and resumption of growth. Recently, a dehydrin cDNA clone was isolated and sequenced, and shown to hybridize to messages likely to encode all three dehydrins. In the present study, expression of dehydrins was examined in blueberry cultivars in response to drought and low-temperature treatment and in cell suspension cultures in response to low temperature and ABA treatment. During 32 days of drought stress, relative shoot water content dropped to 51% to 90%, depending upon cultivars. For cold stress experiments, cultivars with different chilling requirements and levels of cold hardiness were kept at 4 °C for 5 weeks. Cell suspension cultures were held at 4 °C for up to 2 weeks. For ABA experiment, ABA concentrations ranging from 10-3 to 10-7 M were used. Dehydrins were monitored in response to various treatments at RNA and proteins levels using the cDNA clone and antisera raised against the dehydrins. Interestingly, a previously uncharacterized 30 kDa dehydrin was found to be the major low temperature and ABA-responsive protein in cell suspension cultures.

Chill‐responsive dehydrins in blueberry: Are they associated with cold hardiness or dormancy transitions?

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.

Characterization and expression of dehydrins in water‐stressed Sorghum bicolor

The effect of water deficit was compared between drought‐tolerant (P954035) and drought‐susceptible (P721N) sorghum (Sorghum bicolor [L.] Moench) genotypes. Gas analysis and leaf water potential (ΨW) measurements indicated clear phenotypic differences between the genotypes in response to water deficit. Both genotypes experienced declines in ΨW, net assimilation rate (A), transpiration rate (E) and stomatal conductance (gs) during stress. P954035, however, dried more slowly and maintained higher values for A, E and gs relative to P721N. In vivo labeling studies and immunoblot analysis using an anti‐dehydrin antibody identified a protein of Mr 21 000 which was induced by water deficit and accumulated to similar levels in both genotypes. The observed molecular changes were essentially identical in both genotypes but differed only in the timing of expression. A sorghum dehydrin cDNA, dhnl, was isolated which encodes a hydrophilic protein of approximately 16.3 kDa with a predicted pl of 10.48. The deduced polypeptide sequence contains two lysine‐rich elements (KKGIMDKIKEKLPG) and shares extensive homology with other dehydrins. DHN 1 mRNA was induced by water deficit in seedlings of both drought‐tolerant and drought‐susceptible sorghum genotypes. Water deficit also induced changes in gene expression in mature preflowering sorghum plants. The anti‐dehydrin antibody detected a protein that accumulated in leaves and roots of stressed plants. The level of DHN 1 mRNA increased in the same tissues, but the abundance of this transcript was much higher in leaves and roots of mature plants than in seedlings.

Characterization and expression of dehydrins in water-stressed Sorghum bicolor

Characterization and expression of dehydrins in water-stressed Sorghum bicolor

Lathyrus Dehydrin : A Drought Inducible cDNA Clone — Isolation and Characterization

Dehydrin like transcripts (drought inducible mRNA) accumulated in drought stressed shoots and roots of Lathyrus sativus. ABA also induced the expression of dehydrin in unstressed seedlings but to a lower extent. A cDNA expression library was prepared in lambda ZAP vector from mRNA of drought stressed shoots of Lathyrus sativus cv P-24 and screened with pea dehydrin cDNA probe. One positive clone (∼ 500 bp) was purified and characterised. The partial nucleotide sequence of the clone Lsd, contained a possible open reading frame which would encode a polypeptide with region of significant amino acid sequence similarity to dehydrin from other plant species. The genomic counterpart of Lsd cDNA was found to be present within a fragment of ∼ 3.4 and ∼ 3.2 kb in parent as well as in the somaclones of Lathyrus sativus, by using different restriction enzymes.