Co-expression of xerophyte Zygophyllum xanthoxylum ZxNHX and ZxVP1-1 enhances salt and drought tolerance in transgenic Lotus corniculatus by increasing cations accumulation

2014 ◽  
Vol 41 (2) ◽  
pp. 203 ◽  
Author(s):  
Ai-Ke Bao ◽  
Yan-Wen Wang ◽  
Jie-Jun Xi ◽  
Chen Liu ◽  
Jin-Lin Zhang ◽  
...  

Lotus corniculatus L. is an important legume for forage, but is sensitive to salinity and drought. To develop salt- and drought-resistant L. corniculatus, ZxNHX and ZxVP1-1 genes encoding tonoplast Na+/H+ antiporter and H+-pyrophosphatase (H+-PPase) from a succulent xerophyte Zygophyllum xanthoxylum L., which is well adapted to arid environments through accumulating Na+ in its leaves, were transferred into this forage. We obtained the transgenic lines co-expressing ZxNHX and ZxVP1-1 genes (VX) as well as expressing ZxVP1-1 gene alone (VP). Compared with wild-type, both VX and VP transgenic lines grew better at 200 mM NaCl, and also exhibited higher tolerance and faster recovery from water-deficit stress: these performances were associated with more Na+, K+ and Ca2+ accumulation in their leaves and roots, which caused lower leaf solute potential and thus retained more water. Moreover, the transgenic lines maintained lower relative membrane permeability and higher net photosynthesis rate under salt or water-deficit stress. These results indicate that expression of tonoplast Na+/H+ antiporter and H+-PPase genes from xerophyte enhanced salt and drought tolerance of L. corniculatus. Furthermore, compared with VP, VX showed higher shoot biomass, more cations accumulation, higher water retention, lesser cell membrane damage and higher photosynthesis capacity under salt or water-deficit condition, suggesting that co-expression of ZxVP1-1 and ZxNHX confers even greater performance to transgenic L. corniculatus than expression of the single ZxVP1-1.

2019 ◽  
Vol 5 (2) ◽  
pp. 55-72 ◽  
Author(s):  
Seyedeh Zahra Hosseini ◽  
Ahmad Ismaili ◽  
Seyed Sajad Sohrabi ◽  
◽  
◽  
...  

2019 ◽  
Vol 446 (1-2) ◽  
pp. 343-356 ◽  
Author(s):  
António Teixeira ◽  
Pietro Iannetta ◽  
Kirsty Binnie ◽  
Tracy A. Valentine ◽  
Peter Toorop

Abstract Aims Myxospermous seed mucilage is multifunctional and is often found in seeds (or achenes) of species occupying arid environments where the trait may influence seed-dispersal and -germination of seeds. The seed mucilage may also enhance soil-water retention, −hydraulic conductivity and -stability. However, the relationship between seed mucilage quantity, seed germination and seedling traits across environmental gradients which determine water-deficit stress has not yet been ascertained. Methods Therefore, we characterised and tested the relationship between seed mucilage quantity, water-deficit stress responses of seeds and seedlings of 36 accessions of four different Plantago species (P. albicans L., P. coronopus L., P. lagopus L. and P. anceolata L.). These were gathered from six regions across Europe, which presented environmental gradients (of rainfall and temperature), and varying soil qualities. Results Seed mucilage was significantly greater in seeds of accessions experiencing: highest summer temperatures; lowest summer precipitation; soils of the same warm dry regions which had greater capacity to retain water within narrow pore spaces. Under water-deficit stress, seeds with most mucilage exhibited a lower base water potential for germination, suffered least seedling mortality and exhibited the most successful seedling development. Conclusions The findings indicate that seed mucilage quantity appeared as an ‘adaptive’ trait and there is a relationship between seed-mucilage quantity, seed germination plus seedling survival and development under environmental conditions of highest water-deficit stress.


2016 ◽  
Vol 43 (10) ◽  
pp. 939 ◽  
Author(s):  
Asma Jday ◽  
Kilani Ben Rejeb ◽  
Ines Slama ◽  
Kaouthar Saadallah ◽  
Marianne Bordenave ◽  
...  

Nitric oxide (NO) – an endogenous signalling molecule in plants and animals – mediates responses to biotic and abiotic stresses. In the present study, we examined the role of exogenous application of NO in mediating stress responses in Cakile maritima Scop. seedlings under water deficit stress using sodium nitroprusside (SNP) as NO donor and as a pre-treatment before the application of stress. Water deficit stress was applied by withholding water for 14 days. Growth, leaf water content (LWC), osmotic potential (ψs), chlorophyll, malondialdehyde (MDA), electrolyte leakage (EL), proline and Δ1-pyrroline-5-carboxylate synthetase (P5CS) and proline dehydrogenase (ProDH) protein levels were determined. Enzyme activities involved in antioxidant activities (superoxide dismutase (SOD) and catalase (CAT)) were measured upon withholding water. The results showed that shoot biomass production was significantly decreased in plants subjected to water deficit stress alone. However, in water deficit stressed plants pre-treated with SNP, growth activity was improved and proline accumulation was significantly increased. Proline accumulation was concomitant with the stimulation of its biosynthesis as shown by the accumulation of P5CS proteins. Nevertheless, no significant change in ProDH protein levels was observed. Besides plants showed lower water deficit-induced lipid membrane degradation and oxidative stress after the pretreatment with 100 µM SNP. This behaviour was related to the increased activity of SOD and CAT. Thus, we concluded that NO increased C. maritima drought tolerance and mitigated damage associated with water deficit stress by the regulation of proline metabolism and the reduction of oxidative damage.


2014 ◽  
Vol 41 (11) ◽  
pp. 1107 ◽  
Author(s):  
Jaime Puértolas ◽  
Carlos Ballester ◽  
E. David Elphinstone ◽  
Ian C. Dodd

To test the hypothesis that root growth at depth is a key trait explaining some genotypic differences in drought tolerance in potato (Solanum tuberosum L.), two varieties (Horizon and Maris Piper) differing in drought tolerance were subjected to different irrigation regimes in pots in a glasshouse and in the field under a polytunnel. In the glasshouse, both cultivars showed similar gas exchange, leaf water potential, leaf xylem ABA concentration and shoot biomass independently of whether plants were grown under well watered or water deficit conditions. Under well watered conditions, root growth was three-fold higher in Horizon compared with Maris Piper, 3 weeks after emergence. Water deficit reduced this difference. In the polytunnel, applying 60% or less irrigation volume compared with full irrigation significantly decreased tuber yield in Maris Piper but not in Horizon. This was coincident with the higher root density of Horizon in deep soil layers (>40 cm), where water content was stable. The results suggest that early vigorous root proliferation may be a useful selection trait for maintaining yield of potato under restricted irrigation or rainfall, because it rapidly secures access to water stored in deep soil layers. Although selecting for vigorous root growth may assist phenotyping screening for drought tolerance, these varieties may require particular environmental or cultural conditions to express root vigour, such as sufficiently deep soils or sufficient water shortly after emergence.


2016 ◽  
Vol 107 (2) ◽  
pp. 385 ◽  
Author(s):  
Hamid Mohammadi ◽  
Mohammad Esmailpour ◽  
Ali GHERANPAYE

<p>Water-deficit stress is the most important environmental factors limiting plant growth, and production. Nano-titanium dioxide (nano anataseTiO<sub>2</sub>) can have various profound effects on the crop physiological, biochemical and morphological characteristics. In the present research, the influences of different concentrations ofTiO<sub>2</sub> nanoparticles (NPs) (0, 10 and 40 ppm) and water-deficit stress on Dragonhead (<em>Dracocephalum moldavica</em> L.) were investigated in a factorial experiment based on randomized complete block design with three replications. Results showed that under normal irrigation, foliar application of 10 ppm TiO<sub>2</sub> NPs increased plant shoot dry mass and essential oils content. Under water-deficit stress condition, plants treated with 10 ppm TiO<sub>2</sub> NPs had more proline and much less H<sub>2</sub>O<sub>2</sub> and malondialdehyde content as compared to untreated plants. Therefore, it can be concluded that proper concentration of TiO<sub>2</sub> NPs probably can be used as an exogenous stimuli for improvement of shoot growth and essential oil content in plants. Furthermore, water-deficit stress-induced damages such as oxidative stress and membrane damage can be ameliorated by foliar application of TiO<sub>2</sub> NPs at appropriate concentrations.</p>


Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 694
Author(s):  
Natalija Kravic ◽  
Vojka Babic ◽  
Jelena Vukadinovic ◽  
Danijela Ristic ◽  
Vesna Dragicevic ◽  
...  

Plants reconfigure their metabolic pathways to cope with water deficit. The aim of this study was to determine the status of the physiological parameters and the content of phenolic acids in the upper most ear leaf of maize inbred lines contrasting in drought tolerance in terms of improved plant productivity e.g., increased grain yield. The experiment was conducted under irrigation and rain-fed conditions. In drought-tolerant lines, the effect of water deficit was reflected through a chlorophyll and nitrogen balance index increase followed by a flavonols index decrease. The opposite trend was noticed in drought susceptible inbreds, with the exception of the anthocyanins index. Moreover, in comparison to irrigation treatment, opposite trends in the correlations between grain yield and physiological parameters found under water deficit conditions indicated the activation of different metabolic pathways in defense against water deficit stress. Concerning phenolic acid content, water deficit caused the reduction of protocatechuic, caffeic, and sinapic acid in all inbreds evaluated. However, the highly pronounced increase of ferulic and especially cinnamic acid content under water deficit conditions indicated possible crucial role of these secondary metabolites in preventing the harmful effects of water deficit stress, which, in turn, might be useful in maize breeding selection for drought tolerance.


Author(s):  
X. Wang ◽  
J.R. Caradus ◽  
A.C.P. Chu

Growth of five New Zealand white clover cultivars, Grasslands Kopu, Grasslands Pitau, Grasslands Huia, Grasslands Tahora and Prop, was quantified at differing soil moistures in both the field and the glasshouse. The first trial employed a rain-out shelter to impose two soil water treatments. While there were no differences among the cultivars for leaf water status, there were differences in plant growth parameters in response to water deficit. Water deficit did not significantly affect leaf appearance rate of Prop, although there was a 2- fold difference. There was, however, a 3.5- to 6-fold decrease in leaf appearance rate due to water deficit for the other cultivars. Water deficit did not significantly reduce leaf size for the medium- and small-leaved cultivars Huia, Tahora and Prop; but was halved for Kopu and Pitau. Prop had the lowest stolon growing point survival under water deficit and Pitau the highest. Leaf longevity was greatest for Prop and least for Pitau when grown under optimum water supply, but this pattern was reversed under water deficit stress. The second trial, a pot trial, investigated the response of the same five cultivars to three different soil water regimes (control, mild and severe stress). The growth parameters of smaller-leaved cultivars, particularly Prop, were less affected than the large-leaved cultivars in their response to water deficit. These short-term trials showed that some small-leaved cultivars of white clover have an ability to adjust their growth and habit in response to water deficit more effectively than large-leaved cultivars. Prop was able to maintain a higher leaf appearance rate than other cultivars when grown under water deficit. However, while exhibiting this drought tolerance adaptation the low stolon growing point survival of Prop could result in a poor recovery from drought. Small-leaved cultivars are rarely taprooted, a characteristic of plants adapted to more prolonged drought conditions. The probability of combining these characteristics and improving summer production of white clover through identification of drought tolerance is discussed. Keywords: cultivars, drought, Trifolium repens, variation, water deficit


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Tengale Dipak Bhauso ◽  
Thankappan Radhakrishnan ◽  
Abhay Kumar ◽  
Gyan Prakash Mishra ◽  
Jentilal Ramjibhai Dobaria ◽  
...  

In the changing global environmental scenarios, water scarcity and recurrent drought impose huge reductions to the peanut (Arachis hypogaea L.) crop yield. In plants, osmotic adjustments associated with efficient free radical scavenging ability during abiotic stress are important components of stress tolerance mechanisms. Mannitol, a compatible solute, is known to scavenge hydroxyl radicals generated during various abiotic stresses, thereby conferring tolerance to water-deficit stress in many plant species. However, peanut plant is not known to synthesize mannitol. Therefore, bacterial mtlD gene coding for mannitol 1-phosphate dehydrogenase under the control of constitutive promoter CaMV35S was introduced and overexpressed in the peanut cv. GG 20 using Agrobacterium tumefaciens-mediated transformation. A total of eight independent transgenic events were confirmed at molecular level by PCR, Southern blotting, and RT-PCR. Transgenic lines had increased amount of mannitol and exhibited enhanced tolerance in response to water-deficit stress. Improved performance of the mtlD transgenics was indicated by excised-leaf water loss assay and relative water content under water-deficit stress. Better performance of transgenics was due to the ability of the plants to synthesize mannitol. However, regulation of mtlD gene expression in transgenic plants remains to be elucidated.


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