The physiological and molecular mechanisms of tolerance to osmotic and ionic components of salinity stress are reviewed at the cellular, organ, and whole-plant level. Plant growth responds to salinity in two phases: a rapid, osmotic phase that inhibits growth of young leaves, and a slower, ionic phase that accelerates senescence of mature leaves. Plant adaptations to salinity are of three distinct types: osmotic stress tolerance, Na + or Cl − exclusion, and the tolerance of tissue to accumulated Na + or Cl − . Our understanding of the role of the HKT gene family in Na + exclusion from leaves is increasing, as is the understanding of the molecular bases for many other transport processes at the cellular level. However, we have a limited molecular understanding of the overall control of Na + accumulation and of osmotic stress tolerance at the whole-plant level. Molecular genetics and functional genomics provide a new opportunity to synthesize molecular and physiological knowledge to improve the salinity tolerance of plants relevant to food production and environmental sustainability.

https://rodas5.us.es/file/c2a700e9-8b4a-1970-d343-4a269c302970/1/estres_salino_bibliografia_scorm.zip/files/estres_salino_bibliografia.pdf

Mechanisms of salinity tolerance

So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

▪ Abstract Plant responses to salinity stress are reviewed with emphasis on molecular mechanisms of signal transduction and on the physiological consequences of altered gene expression that affect biochemical reactions downstream of stress sensing. We make extensive use of comparisons with model organisms, halophytic plants, and yeast, which provide a paradigm for many responses to salinity exhibited by stress-sensitive plants. Among biochemical responses, we emphasize osmolyte biosynthesis and function, water flux control, and membrane transport of ions for maintenance and re-establishment of homeostasis. The advances in understanding the effectiveness of stress responses, and distinctions between pathology and adaptive advantage, are increasingly based on transgenic plant and mutant analyses, in particular the analysis of Arabidopsis mutants defective in elements of stress signal transduction pathways. We summarize evidence for plant stress signaling systems, some of which have components analogous to t...

Plant cellular and molecular responses to high salinity.

Salt tolerance and salinity effects on plants: a review.

Scarcity of water is a severe environmental constraint to plant productivity. Drought-induced loss in crop yield probably exceeds losses from all other causes, since both the severity and duration of the stress are critical. Here, we have reviewed the effects of drought stress on the growth, phenology, water and nutrient relations, photosynthesis, assimilate partitioning, and respiration in plants. This article also describes the mechanism of drought resistance in plants on a morphological, physiological and molecular basis. Various management strategies have been proposed to cope with drought stress. Drought stress reduces leaf size, stem extension and root proliferation, disturbs plant water relations and reduces water-use efficiency. Plants display a variety of physiological and biochemical responses at cellular and whole-organism levels towards prevailing drought stress, thus making it a complex phenomenon. CO2 assimilation by leaves is reduced mainly by stomatal closure, membrane damage and disturbed activity of various enzymes, especially those of CO2 fixation and adenosine triphosphate synthesis. Enhanced metabolite flux through the photorespiratory pathway increases the oxidative load on the tissues as both processes generate reactive oxygen species. Injury caused by reactive oxygen species to biological macromolecules under drought stress is among the major deterrents to growth. Plants display a range of mechanisms to withstand drought stress. The major mechanisms include curtailed water loss by increased diffusive resistance, enhanced water uptake with prolific and deep root systems and its efficient use, and smaller and succulent leaves to reduce the transpirational loss. Among the nutrients, potassium ions help in osmotic adjustment; silicon increases root endodermal silicification and improves the cell water balance. Low-molecular-weight osmolytes, including glycinebetaine, proline and other amino acids, organic acids, and polyols, are crucial to sustain cellular functions under drought. Plant growth substances such as salicylic acid, auxins, gibberrellins, cytokinin and abscisic acid modulate the plant responses towards drought. Polyamines, citrulline and several enzymes act as antioxidants and reduce the adverse effects of water deficit. At molecular levels several drought-responsive genes and transcription factors have been identified, such as the dehydration-responsive element-binding gene, aquaporin, late embryogenesis abundant proteins and dehydrins. Plant drought tolerance can be managed by adopting strategies such as mass screening and breeding, marker-assisted selection and exogenous application of hormones and osmoprotectants to seed or growing plants, as well as engineering for drought resistance.

https://hal.archives-ouvertes.fr/hal-00886451/document

Plant drought stress: effects, mechanisms and management

Global Analysis of Gene Networks to Solve complex Abiotic Stress responses, K Shinozaki, RIKEN Tsukuba Institute, Japan and K Yamaguchi-Shinozaki, Japan International Research Center for Agricultural Sciences, Japan The CBF Cold Response Pathways of Arabidopsis and Tomato, J T Vogel, Michigan State University, USA, D Cook, Mississippi State University, USA, S G Fowler and M F Thomashow, Michigan State University, USA Barley Contains a Large CBF Gene Family Associated with Quantitative Cold Tolerance Traits, J S Skinner, J von Zitzewitz, L Marquez-Cedillo, T Filichkin, Oregon State University, USA, P Szucs, Agricultural Research Institute of the Hungarian Academy of Sciences, Hungary, K Amundsen, Michigan State University, USA, E Stockinger, Ohio State University, USA, M F Thomashow, Michigan State University, USA, T H H Chen, and P M Hayes, Oregon State University, USA Structural Organization of Barley CBF Genes Coincident with QTLs for Cold Hardiness, E J Stockinger, H Cheng, Chinese Academy of Agricultural Sciences, China and J Skinner The genetic basis of vernalization response in barley, L L D Cooper, Oregon State University, USA, J von Zitzewitz, J S Skinner, P Szucs, I Karsai, Agriculturtal Research Institute of the Hungarian Academy of Sciences, Hungary, E Francia, A M Stanca, Experimental Institute for Cereal Resources, Italy, N Pecchioni, Universita di Modena e Reggio Emilia, Italy, D A Laurie, John Innes Research Centre, UK T H H Chen, and P M Hayes Vernalization Genes in Winter Cereals, N A Kane, J Danyluk, and F Sarhan, Universite du Quebec a Montreal, Canada A Bulk Segregant Approach to Identify Genetic Polymorphisms Associated with Cold Tolerance in Alfalfa, Y Castonguay, J Cloutier, S Laberge, A Bertrand and R Michaud, Agriculture and Agri-Food Canada, Canada Ectopic Over-expression of AtCBFI in Potato Enhances Freezing Tolerance, M T Pino, J S Skinner, Z Jeknic, E J Park, Oregon State University, USA, P M Hayes, and T H H Chen Over-expression of a Heat-inducible apx Gene Confers Chilling Tolerance to Rice Plants, Y Sato, National Agricultural Research Center for Hokkaido Region, Japan, and H Saruyama, Hokkaido Green-Bio Institute, Japan Physiological and Morphological Alterations Associated with Development of Freezing Tolerance in The Moss Physcomitrella patens, A Minami, M Nagao, Iwate University, Japan, K Arakawa, S Fujikawa, Hokkaido University and D Takezawa, Saitama University, Japan Control of Growth and Cold Acclimation in Silver Birch, M K Aalto and E T Palva, Viikki Biocenter, Finland The Role of the CBF-Dependent Signalling Pathway in Woody Perennials, C Benedict, Umea University, Sweden, J S Skinner, R Meng, Y Chang, Oregon State University, USA, R Bhalerao, Swedish University of Agricultural Sciences, Sweden, C Finn, USDA-ARS, USA, T H H Chen, V Hurry, Umea University, Sweden Functional Role of Winter-accumulating Proteins from Mulberry Tree in adaptation to Winter-induced Stresses, S Fujikawa, N Ukaji, Hokkaido University, Japan, M Nagao, K Yamane, Hokkaido University, Japan, D Takezawa, and K Arakawa The Role of Compatible Solutes in Plant Freezing Tolerance: A Case Study on Raffinose, D K Hincha, E Zuther, M Hundertmark, A G Heyer, Max-Planck-Institut fur Molekulare Pflanzenphysiologie, Germany Dehydration in model membranes and protoplasts: contrasting effects at low, intermediate and high hydrations, K L Koster, University of South Dakota, USA, and G Bryant, RMIT University, Australia Effect of Plasma Membrane-associated Proteins on Acquisition of Freezing Tolerance in Arabidopsis thaliana, Y Tominaga, Universite du Quebec a Montreal, Canada, C Nakagawara, Y Kawamura and M Uemura, Iwate University, Japan.

Cold Hardiness in Plants: Molecular Genetics, Cell Biology and Physiology

Additional index words. Rubus, tissue culture, thidiazuron Abstract. Experiments focusing on plant growth regulatorsʼconcentrations and combina- tions, mineral salt formulations, and TDZ pretreatment formations were conducted to optimize in vitro shoot regeneration from leaf and petiole explants of ʻMarionʼ black- berry. Optimum shoot formation was obtained when stock plants were incubated in TDZ pretreatment medium for 3 weeks before culturing leaf explants on regeneration medium (Woody Plant Medium with 5 µM BA and 0.5 µM IBA) in darkness for 1 week before transfer to light photoperiod (16-hour photoperiod at photosynthetic photon flux of ≈50 µmol·m-2 ·s -1 ) at 23 °C ± 2 °C for 4 weeks. Under these conditions, ≈70% of leaf explants formed ≈40 shoots per petri dish that could be harvested and rooted to form plantlets. Chemical names used: N6 -benzyladenine (BA); 2,4-dichlorophenoxyacetic acid (2,4-D); gibberellic acid (GA 3); indole-3-acetic acid (IAA); indole-3-butyric acid (IBA); α-naph- thaleneacetic acid (NAA); N-phenyl-Nʼ-1,2,3-thidiazol-5-ylurea (thidiazuron (TDZ)).

/pdf/improving-in-vitro-plant-regeneration-from-leaf-and-petiole-ipg9vrmrb0.pdf

Improving In Vitro Plant Regeneration from Leaf and Petiole Explants of `Marion' Blackberry

Short days (SDs) in autumn induce growth cessation, bud set, cold acclimation, and dormancy in trees of boreal and temperate forests, and these responses occur earlier in northern than in southern genotypes. Nevertheless, we know little about whether this variation results from differential perception of SDs or differential downstream responses to the SD signal or a combination of the two. We compared global patterns of SD-regulated gene expression in the stems of hybrid poplar (Populus trichocarpa × Populus deltoides) clones that differ in their SD-induced growth cessation in order to address this question. The timing of cessation of cambial cell division caused by SDs differed between the clones and was coincident with the change in the pattern of expression of the auxin-regulated genes. The clones also differed in the timing of their SD-regulated changes in the transcript abundance of genes associated with cold tolerance, starch breakdown, and storage protein accumulation. By analyzing the expression of homologs of FLOWERING LOCUS T, we demonstrated that the clones differed little in their perception of SDs under the growth conditions applied but differed substantially in the downstream responses manifested in the timing and magnitude of gene expression after SD treatment. These results demonstrate the existence of factors that act downstream of SD perception and can contribute to variation in SD-regulated adaptive photoperiodic responses in trees.

Components Acting Downstream of Short Day Perception Regulate Differential Cessation of Cambial Activity and Associated Responses in Early and Late Clones of Hybrid Poplar

The effects of hydrogen cyanamide (H 2 CN 2 ) on budbreak and phytotoxicity of 1-year-old potted peach trees [Prunus persica (L.) Batsch. cv. Redhaven] over a wide range of concentrations at several stages of dormancy were studied. Endodormancy (180 o GS; degree growth stage) began on 1 Oct. Maximum intensity of endodormancy (270 o GS) was reached after the plants were exposed to 320 chill units on 1 Nov., and 50% of the buds were broken at 860 chill units on 1 Dec (...)

/pdf/hydrogen-cyanamide-induced-budbreak-and-phytotoxicity-in-2f697kr2fo.pdf

Tony H. H. Chen

Papers

Cold Hardiness in Plants: Molecular Genetics, Cell Biology and Physiology

Improving In Vitro Plant Regeneration from Leaf and Petiole Explants of `Marion' Blackberry

Components Acting Downstream of Short Day Perception Regulate Differential Cessation of Cambial Activity and Associated Responses in Early and Late Clones of Hybrid Poplar

Hydrogen Cyanamide-induced Budbreak and Phytotoxicity in `Redhaven' Peach Buds

Genetic engineering of the biosynthesis of glycinebetaine enhances the fruit development and size of tomato.