scholarly journals Sugar/osmoticum levels modulate differential abscisic acid-independent expression of two stress-responsive sucrose synthase genes in Arabidopsis

1999 ◽  
Vol 344 (2) ◽  
pp. 503-509 ◽  
Author(s):  
Annabelle DÉJARDIN ◽  
Lubomir N. SOKOLOV ◽  
Leszek A. KLECZKOWSKI
Keyword(s):  
Signal Transduction ◽  
Abscisic Acid ◽  
Cold Stress ◽  
Osmotic Potential ◽  
Sucrose Synthase ◽  
Cellular Response ◽  
Expression Profiles ◽  
Soluble Sugars ◽  
Leaf Osmotic Potential ◽  
Detached Leaves

Sucrose synthase (Sus) is a key enzyme of sucrose metabolism. Two Sus-encoding genes (Sus1 and Sus2) from Arabidopsis thaliana were found to be profoundly and differentially regulated in leaves exposed to environmental stresses (cold stress, drought or O2 deficiency). Transcript levels of Sus1 increased on exposure to cold and drought, whereas Sus2 mRNA was induced specifically by O2 deficiency. Both cold and drought exposures induced the accumulation of soluble sugars and caused a decrease in leaf osmotic potential, whereas O2 deficiency was characterized by a nearly complete depletion in sugars. Feeding abscisic acid (ABA) to detached leaves or subjecting Arabidopsis ABA-deficient mutants to cold stress conditions had no effect on the expression profiles of Sus1 or Sus2, whereas feeding metabolizable sugars (sucrose or glucose) or non-metabolizable osmotica [poly(ethylene glycol), sorbitol or mannitol] mimicked the effects of osmotic stress on Sus1 expression in detached leaves. By using various sucrose/mannitol solutions, we demonstrated that Sus1 was up-regulated by a decrease in leaf osmotic potential rather than an increase in sucrose concentration itself. We suggest that Sus1 expression is regulated via an ABA-independent signal transduction pathway that is related to the perception of a decrease in leaf osmotic potential during stresses. In contrast, the expression of Sus2 was independent of sugar/osmoticum effects, suggesting the involvement of a signal transduction mechanism distinct from that regulating Sus1 expression. The differential stress-responsive regulation of Sus genes in leaves might represent part of a general cellular response to the allocation of carbohydrates during acclimation processes.

Response of orchard 'Washington Navel' orange, Citrus sinensis (L.) Osbeck, to saline irrigation water. I. Canopy characteristics and seasonal patterns in leaf osmotic potential, carbohydrates and ion concentrations

1989 ◽  
Vol 40 (2) ◽  
pp. 359 ◽  
Author(s):  
J Lloyd ◽  
H Howie
Keyword(s):  
Leaf Area ◽  
Irrigation Water ◽  
Osmotic Potential ◽  
Citrus Sinensis ◽  
Soluble Sugars ◽  
Seasonal Patterns ◽  
Navel Orange ◽  
Washington Navel ◽  
Leaf Osmotic Potential ◽  
Chloride Concentrations

Effects of irrigation water salinity on tree canopy volume, leaf area, rates of leaf abscission and production, as well as seasonal patterns in leaf osmotic potential (=), starch, soluble sugars and sodium and chloride concentrations were determined for 24-year-old 'Washington Navel' orange trees (Citrus sinensis [L.] Osbeck) on sweet orange (C. sinensis) rootstock. Trees had been irrigated with water containing either 5 or 20 mol NaCl m-3 for 5 years prior to measurements.Trees irrigated with 20 mol NaCl m-3 had a greater number of vegetative flushes in spring. This occurred at the expense of flowering, as numbers of reproductive and mixed flushes were reduced by salinity. Despite a high number of vegetative buds on trees irrigated with 20 mol NaCl m-3, leaf area was still less than low salinity trees.Extensive abscission of spring flush leaves occurred from mid-summer onwards for trees irrigated with 20 mol NaCl m-3. This was not a consequence of leaf water deficit, as more negative leaf osmotic potentials resulting from increased foliar sodium and chloride concentrations resulted in maintenance of leaf turgor. Excessive concentrations of sodium and/or chloride may have been responsible for abscission observed. Some acclimation of foliage to salinity was evident.Irrespective of salinity treatment, leaf osmotic potential became more negative as the season progressed. This was partly due to increased concentrations of soluble sugars in foliage during autumn and winter. Levels of soluble sugars and starch were consistently lower in leaves on trees irrigated with high salinity water, indicating that production rather than utilization of carbohydrate may limit citrus productivity under saline conditions.

scholarly journals The Role of Carbohydrates in Active Osmotic Adjustment in Apple under Water Stress

1992 ◽  
Vol 117 (5) ◽  
pp. 816-823 ◽  
Author(s):  
Zhongchun Wang ◽  
Gary W. Stutte
Keyword(s):  
Water Stress ◽  
Malus Domestica ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Soluble Sugars ◽  
Sugar Alcohol ◽  
Apple Trees ◽  
Mature Leaves ◽  
Leaf Osmotic Potential

Greenhouse grown 2-year-old potted `Jonathan' apple trees (Malus domestica Borkh.) were subjected to various levels of water stress in February. Midday leaf water potential (ψW), leaf osmotic potential (ψS), soluble sugars, and starch contents of mature leaves were measured throughout the development of water stress to determine whether active osmotic adjustment could be detected and whether carbohydrates were involved. Active adjustments of 0.6 MPa were observed 3 and 5 days, respectively, after water stress was initiated. Leaf turgor potential (ψP) could not be maintained through the osmotic adjustment when ψW dropped below -1.6 MPa. Sorbitol, glucose, and fructose concentrations increased while sucrose and starch levels decreased significantly as water stress developed, strongly suggesting that sugar alcohol and monosaccharide are the most important osmotica for adjustment. Sorbitol was a primary carbohydrate in the cell sap and accounted for > 50% of total osmotic adjustment. The partitioning of newly fixed W-labeled photosynthates in mature leaves was not affected by water stress immediately after the 30-min 14CO2 treatment. All the W-labeled carbohydrates decreased in the labeled leaves very rapidly after 14CO2 labeling. The decrease in 14C-sorbitol was greater than the decrease in other carbohydrates under both well-watered and stressed conditions. After 24 hours of water stress, however, the percentage of 14C-sorbitol increased while the percentages of sucrose, starch, glucose, and fructose decreased significantly with increasing levels of stress. The ratio of 14C-sorbitol in leaves with ψW = -3.5 MPa to leaves with ψW = -0.5 MPa was significantly higher than that of 14C-sucrose, 14C-glucose, W-fructose, or 14C-starch.

scholarly journals MaRING2: A Positive Regulator of an Abscisic Acid-dependent Response to Cold Stress from Banana Fruit

2015 ◽  
Vol 140 (4) ◽  
pp. 373-382
Author(s):  
Jiao Chen ◽  
De-bao Yuan ◽  
Chao-zheng Wang ◽  
Yi-xing Li ◽  
Fen-fang Li ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Cold Stress ◽  
Expression Profiles ◽  
Functional Characterization ◽  
Gene Expression Profiles ◽  
Defense Responses ◽  
Cauliflower Mosaic Virus ◽  
35S Promoter ◽  
Banana Fruit ◽  
Positive Regulator

Many reports indicate that an abundance of really interesting new gene (RING) play key roles in regulating defense responses against abiotic and biotic stresses in plants. In this study, the cloning and functional characterization of a RING gene, MaRING2, in banana (Musa acuminata) fruit are reported. MaRING2 belongs to the NEP1-interacting protein (NIP) RING-H2 finger protein family. Gene expression profiles revealed that MaRING2 was cold responsive and induced by abscisic acid (ABA) treatment during cold storage. In this study, the MaRING2 under control of the Cauliflower mosaic virus 35S (CaMV 35S) promoter was transformed to tobacco (Nicotiana benthamiana) using agrobacterium (Agrobacterium tumefaciens)-mediated transformation. The resultant MaRING2-overexpressing transgenic plants (35S:MaRING2) exhibited significantly increased tolerance to low temperatures and were hypersensitive to exogenous ABA in terms of germination and early seedling growth. In addition, overexpression of MaRING2 enhanced the expression of stress-responsive genes under normal (before cold stress) or cold conditions. These results demonstrate the biological role of MaRING2 in conferring cold tolerance. Taken together, these results suggest that MaRING2, a C3H2C3-type RING protein, is a positive regulator of the ABA-dependent stress response.

Differential performance of two forage species, Medicago truncatula and Sulla carnosa, under water-deficit stress and recovery

2013 ◽  
Vol 64 (3) ◽  
pp. 254 ◽  
Author(s):  
Aida Rouached ◽  
Inès Slama ◽  
Walid Zorrig ◽  
Asma Jdey ◽  
Caroline Cukier ◽  
...  
Keyword(s):  
Water Deficit ◽  
Medicago Truncatula ◽  
Osmotic Potential ◽  
Soluble Sugar ◽  
Soluble Sugars ◽  
Membrane Integrity ◽  
Shoot Biomass ◽  
Water Deficit Stress ◽  
Leaf Osmotic Potential ◽  
Forage Species

The response patterns during water deficit stress and subsequent recovery of two forage species, Medicago truncatula and Sulla carnosa, were studied. After germination and pre-treatment, seedlings were individually cultivated for two months under two irrigation modes: 100% and 33% of field capacity. Measured parameters were plant growth, water relations, leaf osmotic potential, lipid peroxidation, and leaf inorganic (Na+ and K+) and organic (proline and soluble sugars) solute contents, as well as delta-1-pyrroline-5-carboxylate synthase (P5CS) and proline dehydrogenase (PDH) activities. Our results showed that under control conditions, and in contrast to roots, no significant differences were observed in shoot biomass production between the two species. However, when subjected to water-deficit stress, M. truncatula appeared to be more tolerant than S. carnosa (reduction by 50 and 70%, respectively). In the two studied species, water-deficit stress led to an increase in root/shoot ratio and leaf proline and soluble sugar contents, and a decrease in leaf osmotic potential. Enzymatic assay revealed that in the two species, P5CS activity was stimulated whereas that of PDH was inhibited under stress conditions. Despite greater accumulation of proline, sugar, and potassium in leaves of S. carnosa, M. truncatula was more tolerant to water deficit. This was essentially due to its capacity to control tissue hydration and water-use efficiency, in addition to its greater ability to protect membrane integrity. Following stress relief, M. truncatula and S. carnosa showed partial re-establishment of growth capacity.

scholarly journals Abscisic Acid and Sulfate Offer a Possible Explanation for Differences in Physiological Drought Response of Two Maize Near-Isolines

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1713
Author(s):  
Avat Shekoofa ◽  
Thomas R. Sinclair
Keyword(s):  
Abscisic Acid ◽  
Transpiration Rate ◽  
Osmotic Potential ◽  
Zea Mays L ◽  
Rate Sensitivity ◽  
Short Exposure ◽  
Detached Leaves ◽  
Whole Plants ◽  
Hydroponically Grown ◽  
Response To Water

The hypothesis was tested that differences in response to water-deficits between low osmotic potential (LOP) and high osmotic potential (HOP) maize (Zea mays L.) near-isolines were associated with differences in transpiration rate sensitivity to abscisic acid (ABA) and/or sulfate. In a series of four experiments, decreases in transpiration rate (DTR) of whole plants and fully expanded leaves were measured in response to treatments of 1.0 µM ABA and 15 mM MgSO4 singly and in combination following long (2 day) and short (180 min) exposures. There was little evidence that intact plants grown on soil were responsive to the treatments. For hydroponically grown plants subjected to long exposure, there was similarly no response to treatments. Further, the short exposure of hydroponically grown plants to solely ABA or a combination of chemicals resulted in no sensitivity in DTR for either of the near-isolines. On the other hand, when these plants were fed sulfate, the transpiration was stimulated by about 20% for the LOP and 60% for the HOP. Detached leaves proved to be the most sensitive to treatment. Treatment with the two chemicals singly caused essentially equivalent DTR in the two near-isolines. However, treatment with ABA plus sulfate resulted in different DTR between the two near-isolines with values of 65% for the LOP and 16% for the HOP near-isoline. Overall, these results showed that the short exposure treatment of hydroponically grown plants or detached leaves supported the hypothesis of different transpiration rate sensitivities of the near-isolines in response to ABA and sulfate treatments.

Immune-related gene expression of Apis mellifera larvae in response to cold stress and Abscisic Acid (ABA) dietary supplementation

2020 ◽  
Vol 59 (4) ◽  
pp. 669-676 ◽  
Author(s):  
Pedro Negri ◽  
Leonor Ramirez ◽  
Silvina Quintana ◽  
Nicolas Szawarski ◽  
Matías D. Maggi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Abscisic Acid ◽  
Apis Mellifera ◽  
Cold Stress ◽  
Dietary Supplementation ◽  
Related Gene ◽  
Immune Related Gene

Comparative expression profiles of maize genes from a water stress-specific cDNA macroarray in response to high-salinity, cold or abscisic acid

Plant Science ◽  
2006 ◽  
Vol 170 (6) ◽  
pp. 1125-1132 ◽  
Author(s):  
Jun Zheng ◽  
Jinfeng Zhao ◽  
Jinpeng Zhang ◽  
Junjie Fu ◽  
Mingyue Gou ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
High Salinity ◽  
Expression Profiles ◽  
Cdna Macroarray
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