Papers by Francisco Pérez-alfocea
Endogenous hormones response to cytokinins with regard to organogenesis in explants of peach (Prunus persica L. Batsch) cultivars and rootstocks (P. persica × Prunus dulcis)
Plant Physiology and Biochemistry, 2014
Organogenesis in peach (Prunus persica L. Batsch) and peach rootstocks (P. persica × Prunus dulci... more Organogenesis in peach (Prunus persica L. Batsch) and peach rootstocks (P. persica × Prunus dulcis) has been achieved and the action of the regeneration medium on 7 phytohormones, zeatin (Z), zeatin riboside (ZR), indole-3-acetic acid (IAA), abscisic acid (ABA), ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), salicylic acid (SA), and jasmonic acid (JA), has been studied using High performance liquid chromatography - mass spectrometry (HPLC-MS/MS). Three scion peach cultivars, 'UFO-3', 'Flariba' and 'Alice Bigi', and the peach × almond rootstocks 'Garnem' and 'GF677' were cultured in two different media, Murashige and Skoog supplemented with plant growth regulators (PGRs) (regeneration medium) and without PGRs (control medium), in order to study the effects of the media and/or genotypes in the endogenous hormones content and their role in organogenesis. The highest regeneration rate was obtained with the peach × almond rootstocks and showed a lower content of Z, IAA, ABA, ACC and JA. Only Z, ZR and IAA were affected by the action of the culture media. This study shows which hormones are external PGRs-dependent and what is the weight of the genotype and hormones in peach organogenesis that provide an avenue to manipulate in vitro organogenesis in peach.
Evaluation of salt tolerance in cultivated and wild tomato species through in vitro shoot apex culture
Plant Cell Tissue and Organ Culture, 1998
Page 1. Plant Cell, Tissue and Organ Culture 53: 19–26, 1998. © 1998 Kluwer Academic Publishers. ... more Page 1. Plant Cell, Tissue and Organ Culture 53: 19–26, 1998. © 1998 Kluwer Academic Publishers. Printed in the Netherlands. 19 Evaluation of salt tolerance in cultivated and wild tomato species through in vitro shoot apex culture ...
Elucidation of salt stress defense and tolerance mechanisms of crop plants using proteomics-Current achievements and perspectives
PROTEOMICS, 2013
Salinity is a major threat limiting the productivity of crop plants. A clear demand for improving... more Salinity is a major threat limiting the productivity of crop plants. A clear demand for improving the salinity tolerance of the major crop plants is imposed by the rapidly growing world population. This review summarizes the achievements of proteomic studies to elucidate the response mechanisms of selected model and crop plants to cope with salinity stress. We also aim at identifying research areas, which deserve increased attention in future proteome studies, as a prerequisite to identify novel targets for breeding strategies. Such areas include the impact of plant-microbial communities on the salinity tolerance of crops under field conditions, the importance of hormone signaling in abiotic stress tolerance, and the significance of control mechanisms underlying the observed changes in the proteome patterns. We briefly highlight the impact of novel tools for future proteome studies and argue for the use of integrated approaches. The evaluation of genetic resources by means of novel automated phenotyping facilities will have a large impact on the application of proteomics especially in combination with metabolomics or transcriptomics.
Symbiosis, 2010
In this study, the effect of 100 mM NaCl on physiological and biochemical responses were investig... more In this study, the effect of 100 mM NaCl on physiological and biochemical responses were investigated in nodules of two Medicago ciliaris lines differing in salt tolerance (TNC 1.8 and TNC 11.9). Results showed that, on the basis of growth and nitrogen fixation, the line TNC 1.8 proved more salt tolerant than TNC 11.9. The salt-induced oxidative stress (membrane lipid peroxidation, leghemoglobin degradation, antioxidant activities reduction) occurred similarly in nodules of both lines. The tolerant line TNC 1.8 showed a better capacity to preserve higher sucrolytic activities and maintained higher nodule malate concentration, although total organic acids decreased in both lines. The higher amount of organic acids in the tolerant line seems to be related to its capacity to maintain higher NH 4 nodule concentration in comparison with the sensitive line. Although salt stress reduced concentrations of the majority of amino acid in both lines, the decrease of the most preponderant amino acids glycine, valine, aspartate and glutamate was more accentuated in the sensitive line TNC 11.9. However, alanine concentration increased in the nodules of this sensitive line, suggesting a higher incidence of stress-induced hypoxia. The present study provides further evidence that salt tolerance of nitrogen fixation in the tolerant line is linked to a more effective supply of malate to bacteroids which allows the synthesis of amino acids required to maintain both plant and nodule growth.
Theoretical and Applied Genetics, 2010
Grafting desirable crop varieties on stress-tolerant rootstocks provides an opportunity to increa... more 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 signiWcant 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 aVected 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 Wve 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.
Scientia Horticulturae, 2013
Sweet pepper crop yield and quality in some Mediterranean regions are negatively affected by the ... more Sweet pepper crop yield and quality in some Mediterranean regions are negatively affected by the high radiation and temperature during the spring-summer harvesting period. Although the use of shading screens is a common, although expensive, strategy to minimize the impact of thermal stress, the use of grafting onto adequate rootstocks could be an interesting alternative to maintain commercial fruit yield and quality under non-shaded conditions, in addition to providing other advantages such as resistance to soil-borne diseases. In order to test this hypothesis, we studied the behaviour of 'Herminio' plants ungrafted and grafted onto three different commercial rootstocks (Atlante, Creonte and Terrano) under non-shaded and shaded conditions. The use of shading screen proved to be efficient in improving vegetative growth, photosynthesis, transpiration and leaf water status, and for reducing the unmarketable yield, especially the incidence of the sunscalded fruits, compared to non-shaded conditions. In general, the grafted plants performed better than the ungrafted ones under both growing conditions, but the differences were more evident under non-shaded conditions. The plants grafted onto Atlante produced up to 40% more leaf area than the other combinations but did not increase yield nor reduce the incidence of the sunscald disorder. However, grafting onto Creonte did not significantly affect leaf biomass but increased the total and marketable fruit yield by 30% and 50% under non-shaded and shaded conditions compared to the ungrafted plants, respectively. Moreover, this rootstock maintained 30-60% higher leaf photosynthetic activity and reduced the amount of sunscalded fruits by 6% during the harvest period in non-shaded conditions. However some fruit nutritional parameters were affected. These results suggest that improved protection of the photosynthetic apparatus is more efficient for increasing yield and for reducing sunscald disorder than more foliage per se under non-shaded conditions, in the absence of any other imposed stress. The use of the rootstock Creonte is an efficient alternative to using shading screens in greenhouse-grown sweet peppers.
Plant, Cell & Environment, 2010
Hydrogen peroxide (H2O2) increased the germination percentage of pea seeds, as well as the growth... more Hydrogen peroxide (H2O2) increased the germination percentage of pea seeds, as well as the growth of seedlings in a concentration-dependent manner. The effect of H2O2 on seedling growth was removed by incubation with 10 mM ABA. The H2O2-pretreatment produced an increase in ascorbate peroxidase (APX), peroxidase (POX) and ascorbate oxidase (AAO). The increases in these ascorbateoxidizing enzymes correlated with the increase in the growth of the pea seedlings as well as with the decrease in the redox state of ascorbate. Moreover, the increase in APX activity was due to increases in the transcript levels of cytosolic and stromal APX (cytAPX, stAPX).
Plant, Cell & Environment, 2009
Tomato crop productivity under salinity can be improved by grafting cultivars onto salt-tolerant ... more Tomato crop productivity under salinity can be improved by grafting cultivars onto salt-tolerant wild relatives, thus mediating the supply of root-derived ionic and hormonal factors that regulate leaf area and senescence.A tomato cultivar was grafted onto rootstocks from a population of recombinant inbred lines (RILs) derived from a Solanum lycopersicum ¥ Solanum cheesmaniae cross and cultivated under moderate salinity (75 mM NaCl). Concentrations of Na + ,K + and several phytohormones [abscisic acid (ABA); the cytokinins (CKs) zeatin, Z; zeatin riboside, ZR; and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC)] were analysed in leaf xylem sap in graft combinations of contrasting vigour. Scion leaf area correlated with photosystem II (PSII) efficiency (Fv/Fm) and determined fruit productivity. Xylem K + (but not Na + ), K + /Na + , the active CK Z, the ratio with its storage form Z/ZR and especially the ratio between CKs and ACC (Z/ACC and Z + ZR/ACC) were positively loaded into the first principal component (PC) determining both leaf growth and PSII efficiency. In contrast, the ratio ACC/ABA was negatively correlated with leaf biomass. Although the underlying physiological mechanisms by which rootstocks mediate leaf area or chlorophyll fluorescence (and thus influence tomato salt tolerance) seem complex, a putative potassium-CK interaction involved in regulating both processes merits further attention.
Plant Signaling & Behavior, 2010
Addendum to: Albacete A, Martínez-Andújar C, Ghanem ME, Acosta M, Sanchez-Bravo J, Asins MJ, et a... more Addendum to: Albacete A, Martínez-Andújar C, Ghanem ME, Acosta M, Sanchez-Bravo J, Asins MJ, et al. Rootstock-mediated changes in xylem ionic and hormonal status are correlated with delayed leaf senescence and increased leaf area and crop productivity in salinised tomato.
Plant Science, 2002
With the aim of determining whether the rootstock effect depends on the shoot genotype, two disti... more With the aim of determining whether the rootstock effect depends on the shoot genotype, two distinctly different tomato (Lycopersicon esculentum Mill) genotypes, Moneymaker with excluder character and UC-82B with includer character, were grafted onto a commercial tomato hybrid (cv. Kyndia). Self-grafted plants were used as controls. The rootstock effect was first assessed by growing plants at different NaCl concentrations (0, 50 and 100 mM) under controlled conditions, and by determining the growth and physiological responses of the grafted plants after 35 days of salt treatment. The rootstock did not affect the shoot growth when Moneymaker was used as scion. However, when UC-82B was used as scion, the shoot biomass reduction induced by salinity was lower in plants with rootstock Kyndia than in the self-grafted plants. The effectiveness of the UC-82B grafted plants onto Kyndia was also showed on the basis of fruit yield. The rootstock also induced significant physiological changes in the leaves of these plants, with the most important changes being found in the ion saline accumulation and Na ' /K ' ratio. The Na ' and Cl ( accumulation induced by salinity in leaves of UC-82B was substantially lower when the root of this cultivar had been substituted by that of the cv. Kyndia, whereas the K ' concentration was less reduced by salinity, and consequently the leaf Na ' /K ' ratio values were much lower. These results suggest that the saline ion accumulation in leaves was controlled predominantly by the genotype of the rootstock. In addition, the characteristics of the rootstock able to induce salt tolerance to the shoot depend on the salt tolerance mechanism of the shoot genotype. #
Sucrose and proline accumulation and sugar efflux in tomato leaf discs affected by NaCl and polyethylene glycol 6000 iso-osmotic stresses
Plant Science, 1995
The effect of phlorizin, a reversible inhibitor for glucose transporters and that of PCMBS, a non... more The effect of phlorizin, a reversible inhibitor for glucose transporters and that of PCMBS, a non-permeant water soluble chemical modifier of membrane sulphydryl groups, on proline and sugar accumulation and sugar efflux have been studied in tomato leaf discs (Lycopersicon esculentum L. Mill. cv. Volgogradskij) subjected to stress conditions when incubated in 300 mM NaCl or iso-osmotic solution of non-permeant PEG 6000. The amounts of proline and sucrose found in the tissue were mainly related to the structure of the osmoticum used for the treatment: 12.5 and 56 μmol of proline per gram of dry weight were registered under saline and PEG conditions respectively, while 49.4 and 91.7 μmol of sucrose were found under these conditions. The application of inhibitors provoked a different sugar efflux to the bathing medium: PCMBS enhanced the sugars efflux up to 10 times in saline medium and up to three times under PEG conditions. Surprisingly, the sucrose content in the tissue was always similar to that of the same treatment in the absence of the inhibitor. When exogenous sucrose was supplied to the treated leaf discs, it was found that it exerts two opposite effects on proline accumulation since (1) it prevented the inhibitory effect of both phlorizin and PCMBS in some treatments and (2) it enhanced proline accumulation provoked by these inhibitors in control discs and those treated with PEG. The proline response in relation to the accumulation of sugars for osmotic adjustment and the possibility of an osmoregulated process concerning sucrose synthesis and carbohydrate export under stress conditions are discussed.
Sucrolytic activities in relation to sink strength and carbohydrate composition in tomato fruit growing under salinity
Plant Science, 1996
The effects of low (control), moderate, and high salinity on sucrose metabolism, in relation to f... more The effects of low (control), moderate, and high salinity on sucrose metabolism, in relation to fruit growth, were assayed in a commercial F 1 tomato hybrid (Lycopersicon esculentum L. Mill) Radja (GC-793). High salinity reduced both fruit growth rate and the mature fruit ...
Plant Science, 1998
In leaves of a salt-sensitive tomato species (Lycopersicon esculentum Mill.) and its wild salt-to... more In leaves of a salt-sensitive tomato species (Lycopersicon esculentum Mill.) and its wild salt-tolerant relative species Lycopersicon pennellii (Correll) D'Arcy, changes induced by NaCl stress in carbon compounds (sugars and organic acids), amino acids related to synthesis of polyamines (glutamate, arginine and proline) and polyamines (putrescine, spermidine and spermine) were compared in light and dark after short-term exposure (24 h). The levels of sugars increased more in the salt-sensitive cultivar upon salt stress, especially under light. The changes in the carbon compounds and amino acids were different under light and dark conditions. Thus, in the 200 mM NaCl treated leaves of L. esculentum, the high sugar accumulation found in light was parallel to the no accumulation of both organic acids and amino acids (glutamate and arginine). The opposite response was observed in the treated leaves of L. pennellii with the same stress level in dark. Putrescine increases with salinity were greater in L. pennellii than in L. esculentum either in dark or in light. The higher total polyamine levels in light as opposed to the dark found in both species were rather more due to spermidine and spermine than to putrescine. With regard to the ratio between the diamine putrescine and polyamines, spermidine and spermine, this was always higher in L. pennellii than in L. esculentum. Moreover, the different response between species was clearly observed from the 100 mM NaCl treatment. A higher deviation of glutamate compared to proline seems to be also related to the salt tolerance during the night, as the proline/polyamine ratio increases were higher in the salt-tolerant species.
Responses to NaCl stress of cultivated and wild tomato species and their hybrids in callus cultures
Plant Cell Reports, 1996
If in vitro culture is to be used for evaluating the salt tolerance of tomato hybrids and segrega... more If in vitro culture is to be used for evaluating the salt tolerance of tomato hybrids and segregant populations in a breeding programme, it is previously necessary to get quick and reliable traits. In this work, growth and physiological responses to salinity of two interspecific hybrids between the cultivated tomato (Lycopersicon esculentum Mill) and its wild salt-tolerant species L pennellii are compared to those of their parents. The leaf callus of the first subculture was grown on media amended with 0, 35, 70, 105, 140, 175 and 210 mM NaCl for 40 days. Relative fresh weight growth of callus in response to increased salinity in the culture medium was much greater in L pennellii than in the tomato cultivars, and greater in the hybrids than in the wild species. Moreover, the different salt tolerance degree of hybrids was related to that of female parents. At high salt levels, only Cl(-) accumulation was higher in L pennellii than in tomato cultivars, whereas in the hybrids both Cl(-), and Na(+) accumulation were higher than in their parents. Proline increased with salinity in the callus of all genotypes; these increases were much higher in the tomato cultivars than in L pennellii, and the hybrids showed a similar response to that of the wild species. Salt-treated callus of the tomato cultivars showed significant increases in valine, isoleucine and leucine contents compared to control callus tissue. In contrast, these amino acids in callus tissues of the wild species and hybrids showed a tendency to decrease with increasing salinity.
Plant Cell Reports, 2011
Since plant root systems capture both water and nutrients essential for the formation of crop yie... more Since plant root systems capture both water and nutrients essential for the formation of crop yield, there has been renewed biotechnological focus on root system improvement. Although water and nutrient uptake can be facilitated by membrane proteins known as aquaporins and nutrient transporters, respectively, there is a little evidence that root-localised overexpression of these proteins improves plant growth or stress tolerance. Recent work suggests that the major classes of phytohormones are involved not only in regulating aquaporin and nutrient transporter expression and activity, but also in sculpting root system architecture. Rootspecific expression of plant and bacterial phytohormonerelated genes, using either root-specific or root-inducible promoters or grafting non-transformed plants onto constitutive hormone producing rootstocks, has examined the role of root hormone production in mediating crop stress tolerance. Root-specific traits such as root system architecture, sensing of edaphic stress and root-to-shoot communication can be exploited to improve resource (water and nutrients) capture and plant development under resource-limited conditions. Thus, root system engineering provides new opportunities to maintain sustainable crop production under changing environmental conditions.
Plant and Soil, 1996
The salt tolerance of the commercial F1 tomato hybrid (Lycopersicon esculentum Mill) Radja has be... more The salt tolerance of the commercial F1 tomato hybrid (Lycopersicon esculentum Mill) Radja has been agronomically and physiologically evaluated under greenhouse conditions, using a control (nutrient solution), a moderate (70 mM NaC1 added to the nutrient solution) and a high salt level (140 mM NaC1), applied for 130 days.
Changes in free polyamine levels induced by salt stress in leaves of cultivated and wild tomato species
Physiologia Plantarum, 1997
The effects of N a Cl on endogenous free levels of the poluamines putrescine, spermi dine and spe... more The effects of N a Cl on endogenous free levels of the poluamines putrescine, spermi dine and spermine, and the relationships between polyamines, K + levels and Na + accumulation were determined in leaves of the cultivated tomato (Lycopersicon esculentum Mill.) and its wild, ...
Physiologia Plantarum, 2003
The different growth responses under control and moderate salinity (70 mM NaCl) in relation to th... more The different growth responses under control and moderate salinity (70 mM NaCl) in relation to the carbon partitioning and sucrose metabolism in developing tomato fruits [20 days after anthesis (DAA), start of ripening and ripe stages] were studied in the cultivated tomato Lycopersicon esculentum Mill (cv. H-324-1), in the wild relative species L. cheesmanii (ac. LA-530) (hexose-accumulators), L. chmielewskii (ac. LA-1028) (sucrose-accumulator) and in two interspecific F 1 hybrids (hexose-accumulators) (F1-530: H-324-1 Â A-530, F1-1028: H-324-1 Â A-1028). The higher salt-tolerance of the wild species and hybrids with respect to the domestic tomatoes was also observed at the fruit level because these genotypes were less affected in the assimilation of dry weight (DW) under salinity. With the exception of the wild tomatoes, the sink strength, evaluated as the dry matter accumulation rate (mg DW day À1 ) and the sink activity, evaluated as a relative growth rate (mg DW mg À1 day À1 ), were reduced during the early fruit growing period (20 DAA±start ripening). However, a total recovery of growth was registered in the salinized hybrid fruits during the late growing period (start of ripening-ripe fruits). The early reduction in sink activity in the hybrid and domestic fruits was related to a sucrose accumulation and a decrease in the total sucrolytic activity at 20 DAA, especially the cytoplasmic sucrolytic activities sucrose synthase (EC 2.4.1.13) and neutral invertase (EC 3.2.1.26). The further recovery in sink strength of the hybrid fruits was related to the maintenance of the insoluble acid invertase (EC 3.2.1.25) and the induction of the cytoplasmic sucrolytic activities, namely at the start of ripening stage, demonstrating the existence of an inverse relationship between these activities, which suggests a regulatory mechanism in order to maintain the sink capacity. The roles of different enzymes in the control of assimilate import under salinity in relation to the sucrose transport and possible regulatory mechanisms are discussed.
Physiologia Plantarum, 2013
Salt marshes constitute major sinks for heavy metal accumulation but the precise impact of salini... more Salt marshes constitute major sinks for heavy metal accumulation but the precise impact of salinity on heavy metal toxicity for halophyte plant species remains largely unknown. Young seedlings of Kosteletzkya virginica were exposed during 3 weeks in nutrient solution to Cd 5 μM in the presence or absence of 50 mM NaCl. Cadmium (Cd) reduced growth and shoot water content and had major detrimental effect on maximum quantum efficiency (F v /F m ), effective quantum yield of photosystem II (Y(II)) and electron transport rates (ETRs). Cd induced an oxidative stress in relation to an increase in O 2
Physiologia Plantarum, 2009
The tos1 (tomato osmotically sensitive) mutant, isolated from an in vitro screen of root growth d... more The tos1 (tomato osmotically sensitive) mutant, isolated from an in vitro screen of root growth during osmotic stress, was less sensitive to exogenous ABA, but accumulated more ABA under osmotic stress than WT plants. We assessed growth and water relations characteristics of hydroponically grown tos1 seedlings (in the absence of osmotic stress) at low and high evaporative demands. Growth of tos1 was severely inhibited at both high and low evaporative demands. Twenty DAS, WT and tos1 genotypes had a similar leaf water and turgor potential, but mature tos1 plants (45 day old) showed a significant diurnal loss of leaf turgor, with recovery overnight. Increased evaporative demand increased turgor loss of tos1 plants. High evaporative demand at the beginning of the day decreased stomatal conductance of tos1, without diurnal recovery, thus whole plant transpiration was decreased. De-topped tos1 seedlings showed decreased root hydraulic conductance and had a 1.4-fold increase in root ABA concentration. Impaired root function of tos1 plants failed to meet transpirational water demand and resulted in shoot turgor loss, stomatal closure and growth inhibition.
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Papers by Francisco Pérez-alfocea