Increasing salt tolerance in the tomato Cuartero, J; Bolarín, M. C; Asíns, M. J ...
Journal of experimental botany,
03/2006, Letnik:
57, Številka:
5
Journal Article, Conference Proceeding
Recenzirano
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In this paper, a number of strategies to overcome the deleterious effects of salinity on plants will be reviewed; these strategies include using molecular markers and genetic transformation as tools ...to develop salinity-tolerant genotypes, and some cultural techniques. For more than 12 years, QTL analysis has been attempted in order to understand the genetics of salt tolerance and to deal with component traits in breeding programmes. Despite innovations like better marker systems and improved genetic mapping strategies, the success of marker-assisted selection has been very limited because, in part, of inadequate experimental design. Since salinity is variable in time and space, experimental design must allow the study of genotype×environment interaction. Genetic transformation could become a powerful tool in plant breeding, but the growing knowledge from plant physiology must be integrated with molecular breeding techniques. It has been shown that the expression of several transgenes promotes a higher level of salt tolerance in some species. Despite this promising result, the development of a salt-tolerant cultivar by way of transgenesis has still not been achieved. Future directions in order to overcome the present limitations are proposed. Three cultural techniques have proved useful in tomato to overcome, in part, the effects of salinity: treatment of seedlings with drought or NaCl ameliorates the adaptation of adult plants to salinity; mist applied to tomato plants grown in Mediterranean conditions improves vegetative growth and yield in saline conditions; and grafting tomato cultivars onto appropriate rootstocks could reduce the effects of salinity.
The sodium and potassium concentrations in leaf and stem have been genetically studied as physiological components of the vegetative and reproductive development in two populations of F₈ lines, ...derived from a salt sensitive genotype of Solanum lycopersicum cv. Cerasiforme, as female parent, and two salt tolerant lines, as male parents, from S. pimpinellifolium, the P population (142 lines), and S. cheesmaniae, the C population (116 lines). Genetic parameters of ten traits under salinity and five of them under control conditions were studied by ANOVA, correlation, principal component and QTL analysis to understand the global response of the plant. Two linkage maps including some tomato flowering time and salt tolerance candidate genes encoding for SlSOS1, SlSOS2, SlSOS3, LeNHX1, LeNHX3, were used for the QTL detection. Thirteen and 20 QTLs were detected under salinity in the P and C populations, respectively, and four under control conditions. Highly significant and contributing QTLs (over 40%) for the concentrations of Na⁺ and K⁺ in stems and leaves have been detected on chromosome 7 in both the populations. This is the only genomic position where the concentration QTLs for both the cations locate together. The proportion of QTLs significantly affected by salinity was larger in the P population (64.3%, including all QTLs detected under control) than in the C population (21.4%), where the estimated genetic component of variance was larger for most traits. A highly significant association between the leaf area and fruit yield under salinity was found only in the C population, which is supported by the location of QTLs for these traits in a common region of chromososome C1. As far as breeding for salt tolerance is concerned, only two sodium QTLs (lnc1.1 and lnc8.1) map in genomic regions of C1 and C8 where fruit yield QTLs are also located but in both the cases the profitable allele corresponds to the salt sensitive, cultivated species. One of those QTLs, lnc1.1 might involve LeNHX3.
If the main effect of long-term exposure of tomato plants to salinity is the accumulation of toxic concentrations of Na
+ and Cl
− in the leaves, then the selection of ‘excluder’ rootstocks should ...increase tolerance to salinity in grafted tomato plants, independently of the genotype used as the scion. The question addressed in this study is whether shoot genotypes with an ‘excluder’ character are able to increase their salt tolerance when grafted onto rootstocks of the same characteristics. Moneymaker (with excluder character) was grafted onto two root genotypes, Radja and Pera, selected for their very different ability to regulate the transport of saline ions to the shoot over time. Grafting onto either Pera or Radja improved fruit yield compared to the self-grafted plants of Moneymaker (M/M) when the plants were grown at 50
mM NaCl, whereas there was no effect of either rootstock or of grafting
per se (M/M) on fruit yield in the absence of or at 25
mM NaCl. The relationship between the salt responses to mid- and long-term depended on the stress level; after 27
d of 150
mM NaCl treatment, both graft combinations enhanced similarly their salt tolerances as did in the long-term experiment. Moreover, the tolerance induced by rootstock was related to the low rates of saline ion accumulation in their leaves. However, the positive effect of rootstock was only observed with rootstock Pera when the grafted plants were grown at 50
mM NaCl (the same salt level used in the long-term experiment) for 35
d. According to the physiological changes induced by rootstock in the leaves, the different salt responses seem to be due to the fact that the osmotic effect predominated on the toxic effect under these last conditions. Consequently, in order to select rootstocks care must be taken in the timing of any selection process: the stress level and length of exposure to salinity must be sufficient for the true differences in salt tolerance for toxicity to be shown. Taken together, these results show the effectiveness of grafting to enhance fruit yield in tomato and provide evidence that the positive effect induced by rootstock is related to the re-establishment of ionic homeostasis.
Abstract Background Acute rejection (AR) remains a significant cause of graft loss. Better approaches to predict AR are being investigated. Surface CD28 protein is essential for T-cell proliferation ...and survival as well as cytokine production. Patients and Methods Pretransplant CD4+ CD28+ peripheral T cells were examined in 30 liver recipients (LRs) and 31 kidney recipients (KRs) by flow cytometry. Results Pretransplant CD4+ CD28+ T cells in LRs were significantly lower in rejectors than nonrejectors ( P = .002). Furthermore, the total number of CD28 molecules per cell in LRs ( P = .02) as well as KRs ( P = .047) was significantly lower in rejectors than nonrejectors. The healthy group did not display differences when compared with patients with end-stage liver disease or renal failure; however, stratification analysis displayed higher levels of CD4+ CD28+ when compared with rejected LRs ( P = .04) but not KRs. CD28 levels <41.94% were able to discriminate LRs at high risk of AR ( P = .003). Similarly, a total number of CD28 molecules ≤8359 ( P = .031) in LRs and ≤7669 ( P = .046) in KRs correlated with high risk of AR. Conclusion The preliminary results presented herein exhibit a fast and noninvasive method that assists clinicians to prevent AR by monitoring CD4+ CD28+ peripheral T cells.
Grafting desirable crop varieties on stress-tolerant rootstocks provides an opportunity to increase crop salt tolerance. Here, a commercial hybrid tomato variety was grafted on two populations of ...recombinant inbred lines developed from a salt-sensitive genotype of Solanum lycopersicum var. cerasiforme, as female parent, and two salt-tolerant lines, as male parents, from S. pimpinellifolium, the P population, and S. cheesmaniae, the C population, to identify an easy screening method for identifying rootstocks conferring salt tolerance in terms of fruit yield. Potential physiological components of salt tolerance were assessed in the scion: leaf biomass, Na⁺, nutrition, water relations and xylem ABA concentration. A significant correlation between scion fruit yield and scion leaf fresh weight, water potential or the ABA concentration was found in the C population under salinity, but the only detected QTL did not support this relationship. The rootstocks of the P population clearly affected seven traits related to the sodium, phosphorous and copper concentrations and water content of the scion leaf, showing heritability estimates around 0.4 or higher. According to heritability estimates in the P population, up to five QTLs were detected per trait. QTLs contributing over 15% to the total variance were found for P and Cu concentrations and water content of the scion leaf, and the proportion of fresh root weight. Correlation and QTL analysis suggests that rootstock-mediated improvement of fruit yield in the P population under salinity is mainly explained by the rootstock's ability to minimise perturbations in scion water status.
Background. Clinical and molecular mechanisms involved in the cause and time of death of alcoholic cirrhosis (AC) patients undergoing liver transplantation (LT) are not entirely understood. In sudden ...death cases, judicial autopsy practice is mandatory for determining the cause and circumstances of death. The medico-legal autopsy data are essential for helping health authorities to guide future public health activities, assess the effectiveness of health systems, and adopt the necessary preventive measures to improve and adapt the treatments in order to increase these patients’ survival. Objective. Our study aimed to determine the different clinical and sociodemographic causes that influence the different causes of death and the short- and long-term survival of AC patients undergoing liver transplantation. Methods. A total of 122 deceased AC patients undergoing LT were analyzed at different times post-transplantation. The main pre- and post-transplant complications were analyzed in relation to the cause of death and the patient’s survival, as well as the causes and time at which the patient’s death occurred. Results. A total of 53.3% of non-sudden death was observed. A large number of the deaths of AC patients undergoing transplantation were due to non-sudden death, sepsis, and graft failure (GF), the main causes of death in the sample being similar in both sexes. In non-sudden deaths, there were no significant differences between the death rates either related or not related to the liver transplant. Sepsis was the main cause, with the highest percentage (21.3%) of mortality, followed by GF (18.9%) and multiorgan failure (15.6%) at ten years. Furthermore, our results showed how pre-transplant clinical complications, such as viral infections and encephalopathy, influence the age at which multiorgan failure occurs in the transplanted patient. Conclusion. Multiorgan failure is the leading cause of sudden death, with higher mortality during the first year after transplantation, followed by sepsis and GF. Our results show the vulnerability of AC patients, both in the hospital period after the transplant and outside.
To characterize and describe clinical experience with childhood-onset non-infectious uveitis.
A multicenter retrospective multidisciplinary national web-based registry of 507 patients from 21 ...hospitals was analyzed. Cases were grouped as immune disease-associated (IMDu), idiopathic (IDIu) or ophthalmologically distinct. Characteristics of juvenile idiopathic arthritis-associated (non-HLA-B27-related) uveitis (JIAu), IDIu, and pars planitis (PP) were compared.
IMDu (62.3%) and JIAu (51.9%) predominated in young females; and IDIu (22.7%) and PP (13.6%) in older children, without sex imbalance. Ocular complications occurred in 45.3% of cases (posterior synechiae 28%, cataracts 16%, band keratopathy 14%, ocular hypertension 11% and cystoid macular edema 10%) and were associated with synthetic (86%) and biologic (65%) disease-modifying antirheumatic drug (DMARD) use. Subgroups were significantly associated (
< 0.05) with different characteristics. JIAu was typically anterior (98%), insidious (75%), in ANA-positive (69%), young females (82%) with fewer complications (31%), better visual outcomes, and later use of uveitis-effective biologics. In contrast, IDIu was characteristically anterior (87%) or panuveitic (12.1%), with acute onset (60%) and more complications at onset (59%: synechiae 31% and cataracts 9.6%) and less DMARD use, while PP is intermediate, and was mostly bilateral (72.5%), persistent (86.5%) and chronic (86.8%), with more complications (70%; mainly posterior segment and cataracts at last visit), impaired visual acuity at onset, and greater systemic (81.2%), subtenon (29.1%) and intravitreal (10.1%) steroid use.
Prognosis of childhood uveitis has improved in the "biologic era," particularly in JIAu. Early referral and DMARD therapy may reduce steroid use and improve outcomes, especially in PP and IDIu.
The rootstock effect on the fruit yield of a grafted tomato variety was genetically analyzed under salinity using as rootstock two populations of F₉ lines developed from a salt sensitive genotype of ...Solanum lycopersicum var. cerasiforme, as female parent, and two salt tolerant lines, as male parents, from S. pimpinellifolium, the P population (123 lines), and S. cheesmaniae, the C population (100 lines). There were rootstock lines from the two populations (up to 65% in the P population) that raised the fruit yield of the commercial hybrid under saline conditions. It is shown that this salt tolerance rootstock effect is a heritable trait (h ² near 0.3), governed by at least eight QTLs. The most relevant component was the number of fruits. Thus most detected QTLs correspond to this component. In general, QTL gene effects are medium-sized, with contributions from 8.5 up to 15.9% at most, and the advantageous allele comes from the wild, salt tolerant species. Only two fruit yield QTLs on chromosomes P9 and C11 might correspond to fruit yield QTLs of the non-grafted lines indicating their root system dependence. A fruit yield QTL on chromosome 3 is acting epistatically in both populations. The epistatic interactions found were dominant and they were unveiled using the associated marker as cofactor in the composite interval mapping methodology. Therefore, an efficient and profitable utilization of wild germplasm can be carried out through the improvement of rootstocks that confer salt tolerance in terms of fruit yield to the grafted variety.
The goal of this work is to demonstrate the positive effect of high energy ball milling on the magnetocaloric properties of materials based on strontium-calcium doped lanthanum manganite. We report a ...detailed study of crystal structure, magnetic behavior and magnetocaloric effect of La0.7Ca0.3−xSrxMnO3 (0 ≤ x ≤ 0.2, Δx = 0.05) powders, synthesized by assisted high-energy ball milling. The X-ray diffraction patterns disclose the complete formation of manganite with an orthorhombic structure for x ≤ 0.15, and rhombohedral structure for x = 0.2. Magnetic properties show a reduction of the magnetic saturation, and an increase in the Curie temperature with the strontium substitution, in all explored compositions (above room temperature). Arrot curves display that strontium doped manganites exhibit a second-order magnetic transition from ferrimagnetic to paramagnetic order. The magnetocaloric effect was calculated by measuring the isothermal magnetization around the Curie temperature, from 0 to 1.8 T, using Maxwell relations. All the synthesized manganites show magnetocaloric effect larger as compared to that of the parent compounds synthesized by other methods. The un-doped sample (x = 0) presents 7.43 J kg−1 K−1 and 93.29 J kg−1 of maximum magnetic entropy change (|ΔSM|) and the relative cooling power (RCP), respectively, under a low applied field (μoH) of 1.8 T. As it is expected, the introduction of strontium into the manganite, slightly reduces the magnetic entropy at 1.8 T, from 6.29 to 3.47 J kg−1 K−1 for x = 0.05 and x = 0.2, respectively. At the same time, the presence of strontium increases the working temperature above room temperature for strontium contents higer than 0.05, both attributed to the change in the crystal structure. These values are suitable for room-temperature magnetic refrigeration applications, using low magnetic fields (<1.8 T), increasing its potential application in the domestic refrigeration.
Overexpression of the HAL1 gene in yeast has a positive effect on salt tolerance by maintaining a high internal K+ concentration and decreasing intracellular Na+ during salt stress. In the present ...work, the yeast gene HAL1 was introduced into tomato (Lycopersicon esculentum Mill.) by Agrobacterium tumefaciens-mediated transformation. A sample of primary transformants was self-pollinated, and progeny from both transformed and non-transformed plants (controls) were evaluated for salt tolerance in vitro and in vivo. Results from different tests indicated a higher level of salt tolerance in the progeny of two different transgenic plants bearing four copies or one copy of the HAL1 gene. In addition, measurement of the intracellular K+ to Na+ ratios showed that transgenic lines were able to retain more K+ than the control under salt stress. Although plants and yeast cannot be compared in an absolute sense, these results indicate that the mechanism controlling the positive effect of the HAL1 gene on salt tolerance may be similar in transgenic plants and yeast.
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