45 research outputs found
Presence of proline in salinized nutrient solution re-enforces the role of this amino acid in osmoregulation and protects lipid membrane peroxidation in Arabidopsis thaliana
Abstract Very little is known about the effect of proline addition on the accumulation of inorganic solutes (Na ) and soluble sugars in the model plant Arabidopsis thaliana. Therefore, the aim of the present study was to assess the effect of 10 mM proline (P) supply in the culture medium on water status and solute accumulation of Arabidopsis thaliana seedlings exposed to 50 mM NaCl (S). The decrease of leaf osmotic potential was more pronounced in P+S as compared to S plants, indicating that former plants were able to accumulate more compounds involved in the osmotic adjustment process. Leaf potassium concentration was reduced by 15, 21 and 25% in P, S and P+S plants respectively, as compared to the control. When compared to S or P treatments, leaf proline and soluble sugar were more accumulated under P+S treatment. Under saline conditions, exogenous proline increased leaf Na + , Ca 2+ and Mg 2+ concentrations by 27, 281 and 252%, respectively, as compared to the control. Interestingly, proline addition mitigated significantly the deleterious effects of salt on lipid membrane peroxidation. Regarding the contribution of soluble sugars to osmotic adjustment (OA), it amounted to 6% in S or P+S, plants. For proline, its contribution to OA did not exceed 3.4% under salinity (S), whereas in (P+S) treatment, it increased to 14.7%. As a whole, the positive effect of proline exogenous application under saline conditions could be partly explained by the enhanced role of this organic compound in osmoregulation and its likely protective effect against membrane lipid peroxidation
La signalisation lipidique chez les plantes et son rÎle dans la transduction des signaux en réponse aux contraintes hydriques
Les plantes, organismes fixés, ont développé la capacité de
détecter les variations de leur environnement. Cette propriété
est liée à la perception de ces signaux et à leur transduction
par des voies de signalisation pour les traduire en une réponse
adaptative. Parmi ces voies, la signalisation lipidique joue un rĂŽle
considérable chez les végétaux, avec en particulier l'acide
phosphatidique (PA) comme acteur clĂ©. Ce second messager peut ĂȘtre
synthétisé via deux voies impliquant soit des phospholipases D (PLD),
soit des phospholipases C (PLC) et des diacylglycérol kinases (DAGK). La
variation des niveaux de PA peut ĂȘtre modulĂ©e par sa conversion en
diacylglycérolpyrophosphate (DGPP) par les PA kinases (PAK). Les PLCs,
à travers la formation d'IP3 ou de ses dérivés, sont
impliquées dans les variations des teneurs en Ca2+ intracellulaire,
autre second messager essentiel de la signalisation cellulaire. Les
phosphoinositides, comme le PI3P, le PI4P et le PI(4,5)P2, sont
également des éléments importants de la signalisation lipidique.
Ils sont Ă la fois les substrats des PLCs et des PLDs et des seconds
messagers. Dans cet article nous nous sommes attachĂ©s Ă
présenter l'état des connaissances sur ces voies de signalisation
lipidique en mettant l'accent sur les spécificités de ces voies chez
les végétaux par rapport aux autres rÚgnes vivants
La proline, un acide aminĂ© multifonctionnel impliquĂ© dans lâadaptation des plantes aux contraintes environnementales
Outre son rĂŽle dans le mĂ©tabolisme primaire en tant que constituant des protĂ©ines, la proline est lâun des solutĂ©s compatibles le plus frĂ©quemment accumulĂ© en rĂ©ponse Ă des contraintes environnementales variĂ©es et joue un rĂŽle important dans la tolĂ©rance des plantes. La proline a Ă©tĂ© proposĂ©e comme stabilisateur de protĂ©ines et de complexes macromolĂ©culaires, piĂ©geur de radicaux libres et rĂ©gulateur du potentiel redox cellulaire. La concentration intracellulaire de la proline dĂ©pend dâune rĂ©gulation fine entre sa biosynthĂšse et sa dĂ©gradation. Cependant le rĂŽle exact de la proline et les voies de signalisation impliquĂ©es dans la rĂ©gulation de son mĂ©tabolisme ne sont pas encore complĂštement Ă©lucidĂ©s. LâĂ©tude du mĂ©tabolisme de la proline chez les plantes modĂšles permettrait dâacquĂ©rir des informations quant aux mĂ©canismes diffĂ©rentiels mis en Ćuvre par les plantes pour faire face aux contraintes environnementales et dâĂ©tablir des outils pertinents pouvant ĂȘtre utilisĂ©s dans lâamĂ©lioration des plantes cultivĂ©es
La proline, un acide aminĂ© multifonctionnel impliquĂ© dans lâadaptation des plantes aux contraintes environnementales
Outre son rĂŽle dans le mĂ©tabolisme primaire en tant que constituant des protĂ©ines, la proline est lâun des solutĂ©s compatibles le plus frĂ©quemment accumulĂ© en rĂ©ponse Ă des contraintes environnementales variĂ©es et joue un rĂŽle important dans la tolĂ©rance des plantes. La proline a Ă©tĂ© proposĂ©e comme stabilisateur de protĂ©ines et de complexes macromolĂ©culaires, piĂ©geur de radicaux libres et rĂ©gulateur du potentiel redox cellulaire. La concentration intracellulaire de la proline dĂ©pend dâune rĂ©gulation fine entre sa biosynthĂšse et sa dĂ©gradation. Cependant le rĂŽle exact de la proline et les voies de signalisation impliquĂ©es dans la rĂ©gulation de son mĂ©tabolisme ne sont pas encore complĂštement Ă©lucidĂ©s. LâĂ©tude du mĂ©tabolisme de la proline chez les plantes modĂšles permettrait dâacquĂ©rir des informations quant aux mĂ©canismes diffĂ©rentiels mis en Ćuvre par les plantes pour faire face aux contraintes environnementales et dâĂ©tablir des outils pertinents pouvant ĂȘtre utilisĂ©s dans lâamĂ©lioration des plantes cultivĂ©es
How Does Proline Treatment Promote Salt Stress Tolerance During Crop Plant Development ?
International audienceSoil salinity is one of the major abiotic stresses restricting the use of land for agriculture because it limits the growth and development of most crop plants. Improving productivity under these physiologically stressful conditions is a major scientific challenge because salinity has different effects at different developmental stages in different crops. When supplied exogenously, proline has improved salt stress tolerance in various plant species. Under high-salt conditions, proline application enhances plant growth with increases in seed germination, biomass, photosynthesis, gas exchange, and grain yield. These positive effects are mainly driven by better nutrient acquisition, water uptake, and biological nitrogen fixation. Exogenous proline also alleviates salt stress by improving antioxidant activities and reducing Na + and Cl â uptake and translocation while enhancing K + assimilation by plants. However, which of these mechanisms operate at any one time varies according to the proline concentration, how it is applied, the plant species, and the specific stress conditions as well as the developmental stage. To position salt stress tolerance studies in the context of a crop plant growing in the field, here we discuss the beneficial effects of exogenous proline on plants exposed to salt stress through well-known and more recently described examples in more than twenty crop species in order to appreciate both the diversity and commonality of the responses. Proposed mechanisms by which exogenous proline mitigates the detrimental effects of salt stress during crop plant growth are thus highlighted and critically assessed
Abscisic acid-independent and abscisic acid-dependent regulation of proline biosynthesis following cold and osmotic stresses in Arabidopsis thaliana
The role of the phytohormone abscisic acid (ABA) in the regulation of proline synthesis was investigated by following the expression of the At-PSS and At-P5R proline biosynthesis genes in Arabidopsis thaliana wild type, in an ABA-deficient ubal-1 mutant as well as in ABA-insensitive abil-1 and abi2-1 mutants after ABA, cold and osmotic stress treatments. In wild-type and in ABA mutant seedlings, 50 mu M ABA or osmotic stress treatment triggered expression of At-P5S, whereas At-P5R accumulation was scarcely detectable. Expression of either gene was mediated by endogenous ABA since transcript levels were similar in wild-type and in ABA-deficient mutant plants. Proline accumulated to a greater extent after osmotic stress than upon ABA or cold treatment. Thus. ABA-treated abil-1 mutant plants accumulated less proline than the ABA-treated wild type. Upon salt stress, proline accumulated to a lesser extent in abal-1 and abil-1 mutant plants, suggesting an indirect role of ABA on proline accumulation during salt adaptation of the plant. These results indicate that the expression of the genes of the proline biosynthetic pathway is ABA independent upon cold and osmotic treatments, although their expression can be triggered by exogenously applied ABA. However, the endogenous ABA content may affect proline accumulation upon salt stress, suggesting post-transcriptional control of proline biosynthesis in response to NaCl
Characterization of an Arabidopsis thaliana receptor like protein kinase gene activated by salicylic acid and hypo-osmotic and oxidative stresses
info:eu-repo/semantics/publishe