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[EN] In horticulture, grafting is a popular technique used to combine positive traits from two different plants. This is achieved by joining the plant top part (scion) onto a rootstock which contains the stem and roots. Rootstocks can provide resistance to stress and increase plant production, but despite their wide use, the biological mechanisms driving rootstock-induced alterations of the scion phenotype remain largely unknown. Given that epigenetics plays a relevant role during distance signalling in plants, we studied the genome-wide DNA methylation changes induced in eggplant (Solanum melongena) scion using two interspecific rootstocks to increase vigour. We found that vigour was associated with a change in scion gene expression and a genome-wide hypomethylation in the CHH context. Interestingly, this hypomethylation correlated with the downregulation of younger and potentially more active long terminal repeat retrotransposable elements (LTR-TEs), suggesting that graft-induced epigenetic modifications are associated with both physiological and molecular phenotypes in grafted plants. Our results indicate that the enhanced vigour induced by heterografting in eggplant is associated with epigenetic modifications, as also observed in some heterotic hybrids., Part of the computations described in this paper was performed using the University of Birmingham's Compute and Storage for Life Sciences (CaStLeS) service. We are grateful to Dr. J. Paszkowski (Sainsbury Laboratory, Cambridge, UK) and all the members of his research group for the support and fruitful scientific discussions during the experimental work, Dr. J. Griffiths (Sainsbury Laboratory, Cambridge, UK) and K. Jeynes-Cupper (University of Birmingham, Birmingham, UK) for the critical reading of the manuscript; R. Schina (FMI, Basel, Switzerland) for helping in the first stages of eggplant development and for software assistance and the Max Planck Society for the support to H.G.D.

[EN] The provinces of Alicante and Valencia, located on the Mediterranean coast of Spain, have been important viticulture areas since historical times. In the context of the research project CGL2015-70843-R, we initiated different approaches in order to recover ancient cultivars threatened with disappearance, and we developed in-vitro protocols for virus sanitation and in-vitro conservation of the recovered germplasm. Among the historic cultivars, we localized several accessions of cultivars that were commonly grown in the pre-phylloxera era in the provinces of Alicante and Valencia (`Valencí blanc¿, `Valencí negre¿, `Planta Mula¿, `Botó de Gall¿ and `Raïm del Clotet¿). Microsatellite profiles were obtained to confirm or identify the surveyed germplasm, and genetic variability was observed. In addition, a survey was carried out covering the main area of `Monastrell¿ cultivation in the Vinos de Alicante Protected Designation of Origin. This ancient cultivar, also known as `Mourvèdre¿, is cultivated mainly in the southeast of Spain, and is highly adapted to the dry and warm climate of this area. Genotyping by sequencing (GBS) was used to estimate its genetic diversity, and high variability was found. This analysis will provide a large number of high-quality single-nucleotide polymorphisms (SNPs), well distributed across the genome, suitable for genotyping of clones, which will allow the design of strategies to optimize their conservation and use., This study was supported by the project PRPCGL2015-70843-R co-funded with FEDER Funds, and by the Cátedra Cajamar de Economía y Desarrollo Agroambiental de la UMH. We thank Julio García (Consellería de Agricultura, Medio Ambiente, Cambio Climático, y Desarrollo Rural, GVA, Jaume Soler (Botánica Mediterránea SL) and Antonio Olmos (IVIA) for their collaboration in our project.

[EN] The performance of snake melon [Cucumis melo var. flexuosus (L.)] in organic farming was studied under high biotic and salt stress conditions. Soilborne diseases (mainly caused by Macrophomina phaseolina and Neocosmospora falciformis), combined with virus incidence [Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV), and Tomato leaf curl New Delhi virus (ToLCNDV)] and Podosphaera xanthii attacks, reduced yield by more than 50%. Snake melon susceptibility to M. phaseolina and Monosporascus cannonballus was proved in pathogenicity tests, while it showed some degree of resistance to Neocosmospora keratoplastica and N. falciformis. On the contrary, salt stress had a minor impact, although a synergic effect was detected: yield losses caused by biotic stress increased dramatically when combined with salt stress. Under biotic stress, grafting onto the melon F(1)Pat81 and wild Cucumis rootstocks consistently reduced plant mortality in different agroecological conditions, with a better performance compared to classic Cucurbita commercial hybrids. Yield was even improved under saline conditions in grafted plants. A negative effect was detected, though, on consumer acceptability, especially with the use of Cucurbita rootstocks. Cucumis F(1)Pat81 rootstock minimized this side effect, which was probably related to changes in the profile of sugars, acids, and volatiles. Grafting affected sugars and organic acid contents, with this effect being more accentuated with the use of Cucurbita rootstocks than with Cucumis. In fact, the latter had a higher impact on the volatile organic compound profile than on sugar and acid profile, which may have resulted in a lower effect on consumer perception. The use of Cucumis rootstocks seems to be a strategy to enable organic farming production of snake melon targeted to high-quality markets in order to promote the cultivation of this neglected crop., This work was supported by the Spanish Ministerio de Ciencia, Innovacion y Universidades, cofunded with FEDER funds [project nos. AGL2017-85563-C2-1-R and RTA2017-00061-C03-03 (INIA)], and by PROMETEO project 2017/078 (to promote excellence groups) by the Conselleria d'Educacio, Investigacio, Cultura i Esports (Generalitat Valenciana). AF-L is a recipient of a predoctoral fellowship from Generalitat Valenciana.

The performance of snake melon [Cucumis melo var. flexuosus (L.)] in organic farming was studied under high biotic and salt stress conditions. Soilborne diseases (mainly caused by Macrophomina phaseolina and Neocosmospora falciformis), combined with virus incidence [Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV), and Tomato leaf curl New Delhi virus (ToLCNDV)] and Podosphaera xanthii attacks, reduced yield by more than 50%. Snake melon susceptibility to M. phaseolina and Monosporascus cannonballus was proved in pathogenicity tests, while it showed some degree of resistance to Neocosmospora keratoplastica and N. falciformis. On the contrary, salt stress had a minor impact, although a synergic effect was detected: yield losses caused by biotic stress increased dramatically when combined with salt stress. Under biotic stress, grafting onto the melon F1Pat81 and wild Cucumis rootstocks consistently reduced plant mortality in different agroecological conditions, with a better performance compared to classic Cucurbita commercial hybrids. Yield was even improved under saline conditions in grafted plants. A negative effect was detected, though, on consumer acceptability, especially with the use of Cucurbita rootstocks. Cucumis F1Pat81 rootstock minimized this side effect, which was probably related to changes in the profile of sugars, acids, and volatiles. Grafting affected sugars and organic acid contents, with this effect being more accentuated with the use of Cucurbita rootstocks than with Cucumis. In fact, the latter had a higher impact on the volatile organic compound profile than on sugar and acid profile, which may have resulted in a lower effect on consumer perception. The use of Cucumis rootstocks seems to be a strategy to enable organic farming production of snake melon targeted to high-quality markets in order to promote the cultivation of this neglected crop.

[EN] Grapevine is grown as a grafted plant, mainly using phylloxera-resistant rootstocks obtained when this aphid destroyed European vineyards, and the use of a reduced number of rootstocks in each production area is common. This indicates that the genetic variability that is being used could be insufficient to tackle new stress constraints. Changes that will be produced as a consequence of climate change are promoting the development of new rootstocks and the study, in a deeper manner, of those already in use, mainly in relation to drought stress. In this work, we have studied 40 rootstock accessions, including clones of common rootstocks, others developed later, some recovered from old abandoned fields and other, resprouted rootstocks. From these accessions, 19 unique SSR profiles were obtained and chlorotypes were assigned, as no information was available for them in the VIVC database, thus generating new knowledge. Genetic variability was analysed in the 110 Ritcher, 140 Ruggieri and 1103¿Paulsen rootstocks (derived from Vitis berlandieri and Vitis rupestris), commonly used in the countries of greater wine production (Spain, France and Italy), and in the 19 rootstocks with unique profiles. As expected, higher variability was found in the latter. Fortunately, variability was also found in the small sample of which reflects there is variability among the three more-commonly-used rootstocks despite they are half and/or full sibs. Considering all the germplasm analysed, the relationships found agree with a recent report stating that some genotypes had been erroneously assigned, previously, and show that another genotype may not be correct. Variability was also found in clones of several rootstocks, with considerable variability in some of them, including two rootstocks rescued from old abandoned vineyards. This result suggests the possibility of evaluating these materials for other traits. Finally, evaluation of osmotic-stress tolerance was carried out in in vitro culture, using media containing PEG. Micropropagated plants of one rootstock classified as drought-resistant, another reported as sensitive and two others whose classification in the field is variable were used. The results indicate that this methodology can be useful in breeding programmes, to screen the variability in osmotic-stress tolerance among clones and to study root architecture and plasticity., The study was supported by the projects CGL2015-70843-R, MINECO co-funded with FEDER funds, and AGCOOP_D/2018/007, funded by FEADER, MAPA and Conselleria d'Agricultura, Desenvolupament Rural, Emergencia Climatica i Transicio Ecologica (Generalitat Valenciana). The authors thank the owners of nurseries and other members of the viticulture sector (see Table S1) for supplying the different accessions required to carry out this work and A. Frances who collaborated in the evaluation of osmotic stress tolerance.

[EN] Drought stress is one of the major threats to agriculture and concomitantly to food production. Tomato is one of the most important industrial crops, but its tolerance to water scarcity is very low. Traditional plant breeding has a limited margin to minimize this water requirement. In order to design novel biotechnological approaches to cope with this problem, we have screened a plant cDNA library from the halotolerant crop sugar beet (Beta vulgaris L.) for genes able to confer drought/osmotic stress tolerance to the yeast model system upon overexpression. We have identified the gene that encodes BvHb2, a class 2 non-symbiotic hemoglobin, which is present as a single copy in the sugar beet genome, expressed mainly in leaves and regulated by light and abiotic stress. We have evaluated its biotechnological potential in the model plant Arabidopsis thaliana and found that BvHb2 is able to confer drought and osmotic stress tolerance. We also generated transgenic lines of tomato (Solanum lycopersicum) overexpressing BvHb2 and found that the resulting plants are more resistant to drought-induce withering. In addition, transgenic lines overexpressing BvHb2 exhibit increased levels of iron content in leaves. Here, we show that class 2 non-symbiotic plant hemoglobins are targets to generate novel biotechnological crops tolerant to abiotic stress. The fact that these proteins are conserved in plants opens the possibility for using Non-GMO approaches, such as classical breeding, molecular breeding, or novel breeding techniques to increase drought tolerance using this protein as a target., This project was funded by the project PAID-00-10 "Introduccion De Genes Relacionados Con La Tolerancia A Estres Hidrico Y Oxidativo En Distintos Materiales Que Presentan Caracteristicas Utiles Para Su Uso Como Patrones De Plantas Horticolas De Interes Agronomico". (Ref. 2726) from the Universitat Politecnica de Valencia.

[EN] Pot experiments were carried out to characterize the response of two Cucumis metuliferus accessions against (a)virulent Meloidogyne arenaria, M. incognita or M. javanica populations, to Mi1.2 gene and to determine the compatibility and the effect on physicochemical properties of cantaloupe melon. In addition, histopathological studies were conducted. Plants were inoculated in 200 cm3 -pots with 1 J2 cm-3 24 of soil containing sterilized sand a week after transplanting and maintained in a growth chamber at 25 ºC for 40 days. The susceptible cucumber cv. Dasher II or melon cv. Paloma were included for comparison. The number of egg masses and number of eggs per plant were assessed, and the reproduction index (RI) was calculated as the percentage of eggs produced on the C. metuliferus accessions respect those produced on the susceptible cultivars. The compatibility and fruit quality was assessed grafting three scions (two of Charentais type) and one of type Piel de Sapo under commercial greenhouse conditions. The resistance level of both C. metuliferus accessions ranged from highly (RI < 1%) to resistant (1% ¿RI ¿ 10%) irrespective of Meloidogyne populations. Melon plants grafted onto C. metuliferus accession BGV11135 grew as selfgrafted plants and did not modify negatively fruit quality traits. Giant cells induced by RKN on C. metuliferus were mostly poor developed compared to those on cucumber. Furthermore, necrotic areas surrounding the nematode were observed. C. metuliferus accession BGV11135 could be a promising melon rootstock to manage Meloidogyne spp. irrespective of its (a)virulent Mi1.2 condition without melon fruit quality reduction., This work was supported by AGL2013-49040-C2-1-R, and AGL2014-53398-C2-2-R projects from the Spanish Ministry of Economy, Industry and Competitiveness, and cofounded with FEDER Funds. The authors would like to thank Semillas Fito for providing melon cv. Paloma, Dr Christine Vos (Scientia Terrae Research Institute) for her English revision and critical comments of the manuscript and Dr Nuria Escudero (Universitat Politecnica de Catalunya) for her support and critical comments on the manuscript.

Background Somatic embryogenesis is the preferred method for cell to plant regeneration in Vitis vinifera L. However, low frequencies of plant embryo conversion are commonly found. In a previous work we obtained from cut-seeds of a grapevine infected with the Grapevine leafroll associated viruses 1 and 3 (GLRaV-1 and GLRaV-3), high rates of direct regeneration, embryo plant conversion and sanitation. The aim of this study is to evaluate the usefulness of this procedure for regeneration of other grapevine varieties which include some infected with one to three common grapevine viruses (GLRaV-3, Grapevine fanleaf virus (GFLV) and Grapevine fleck virus (GFkV)). As grapevine is highly heterozygous, it was necessary to select from among the virus-free plants those that regenerated from mother tissues around the embryo, (true-to-type). Results Somatic embryogenesis and plant regeneration were achieved in a first experiment, using cut-seeds from the 14 grapevine varieties Airén, Cabernet Franc, Cabernet Sauvignon, Mencía, Merlot, Monastrell, Petit Verdot, Pinot Blanc (infected by GFLV and GFkV), Pinot Gris, Pinot Meunier, Pinot Noir, Syrah, Tempranillo (infected by GFLV), and Verdil. All regenerated plants were confirmed to be free of GFkV whereas at least 68% sanitation was obtained for GFLV. The SSR profiles of the virus-free plants showed, in both varieties, around 10% regeneration from mother tissue (the same genetic make-up as the mother plant). In a second experiment, this procedure was used to sanitize the varieties Cabernet Franc, Godello, Merlot and Valencí Blanc infected by GLRaV-3, GFkV and/or GFLV. Conclusions Cut-seeds can be used as explants for embryogenesis induction and plant conversion in a broad range of grapevine varieties. The high regeneration rates obtained with this procedure facilitate the posterior selection of true-to-type virus-free plants. A sanitation rate of 100% was obtained for GFkV as this virus is not seed-transmitted. However, the presence of GLRaV-3 and GFLV in some of the regenerated plants showed that both viruses are seed-transmitted. The regeneration of true-to-type virus-free plants from all infected varieties indicates that this methodology may represent an alternative procedure for virus cleaning in grapevine. Electronic supplementary material The online version of this article (10.1186/s12870-017-1159-3) contains supplementary material, which is available to authorized users.

In vitro culture represents a tool for the ex situ conservation of a high number of sanitised plants in a reduced space. However, the culture media and/or other growing conditions need to be optimised to minimising plant growth and storage cost. Growth on MW medium was evaluated in the commercial cultivars ‘Airen’, ‘Bobal’, ‘Chardonnay’, ‘Garnacha Blanca’, ‘Moscatel de Alejandria’, ‘Moscatel de Grano Menudo’, ‘Pedro Ximenez’, ‘Pinot Blanc’, ‘Pinot Gris’, ‘Sauvignon Blanc’, and ‘Tempranillo’; the minor cultivars ‘Chelva’, ‘Valenci Negre’, ‘Valenci Blanc’, and ‘Verdil’; and the endangered cv. ‘Esclafacherre’. Different growth rates were observed among cultivars: those with faster growth need to be subcultured every 1.5–2.0 months; those with the slowest growth every 3.5–4.0 months. The effect of halving the sucrose in MW reduced the growth of the cultivars that grew faster without compromising survival. When IBA was removed from MW, growth was also reduced in some cultivars. Therefore, small modific...

In horticulture, grafting is a popular technique used to combine positive traits from two different plants. This is achieved by joining the plant top part (scion) onto a rootstock which contains the stem and roots. Despite its wide use, the biological mechanisms driving rootstock-induced alterations of the scion phenotype remain largely unknown. Given that epigenetics plays a crucial role during distance signalling in plants, we studied the genome-wide changes induced by DNA methylation in eggplant (Solanum melongena) plants grafted onto two interspecific rootstocks used to increase scion vigour. As a control, we compared any epigenetic effect found in such grafts to patterns detected in self-grafted plants. We found that vigour was associated with a specific change in scion gene expression and a genome-wide hypomethylation in CHH context. Interestingly, this hypomethylation correlated with the down-regulation of younger and potentially more active LTR retrotransposons (LTR-TEs), suggesting that graft-induced epigenetic modifications are associated to both physiological and molecular phenotypes in grafted plants. We propose that rootstocks can promote vigour by reducing DNA methylation in the scion genome, following similar principles found in some heterotic hybrids.

Background: The grafting of watermelons (Citrullus lanatus) is a common technique that increases yield under stressful soil conditions. The most common rootstocks for watermelons are Cucurbita hybrids. However, they often have a negative impact on fruit quality. Exploiting novel Citrullus germplasm such as citron melon (Citrullus lanatus var. citroides) is an alternative to avoid these quality problems.; Results: Citron melon has been validated as watermelon rootstock, comparing its effects on watermelon quality to those of Cucurbita hybrids. Larger fruits with thicker rinds were observed in fruits from plants grafted onto both citron and Cucurbita rootstocks. The citron melon had no significant effect on flesh sugars or acid profiles compared to non-grafted watermelons, except for an increase in glucose and malic acid content, which also occurred in the Cucurbita rootstocks. The aroma profile of fruits produced on citron melon was similar to that of the non-grafted and self-grafted controls. The citron rootstock did not display the increased levels of (Z)-6-nonen-1-ol (a compound associated with pumpkin-like odors) found in fruits produced with Cucurbita hybrids.; Conclusion: The low impact of citron melon rootstock on fruit quality, along with the enhanced resistance against nematodes, make the citron a promising alternative to Cucurbita rootstocks. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.

We identified a single plant in a grow out of the eggplant (Solanum melongena L.) variety ‘Black Beauty’ bearing green fruit. ‘Black Beauty’ normally produces violet/black pigmented fruit attributed to anthocyanin accumulation. We selected the green-fruited true-breeding genotype E13GB42 from the S2 generation obtained from selfing of the S0 green-fruited color mutant. Characterization of 12 simple sequence repeat (SSR) markers, eight fruit morphological attributes and fruit yield support E13GB42 arising as a spontaneous mutant of ‘Black Beauty’. With the exception of fruit calyx prickliness, E13GB42 was not significantly different from ‘Black Beauty’ for fruit morphological attributes and yield. E13GB42 exhibited an SSR marker profile identical to that of ‘Black Beauty’ but polymorphic with that of eight violet/black-fruited modern eggplant hybrids, older open-pollinated varieties and landraces. Transcript levels of key anthocyanin biosynthetic genes (Chs, Dfr, and Ans) and regulatory genes (MybC, Myc, and Wd) were significantly lower in the green-fruited E13GB42 mutant in comparison with the black-fruited variety ‘Black Beauty’ at various stages of fruit development ranging from small post-anthesis fruit to full-size marketable fruit. Progeny obtained from selfing of the original mutant and reciprocal crosses with ‘Black Beauty’ produced violet, green, and green with violet striped color classes that together were not compatible with one or two gene inheritance models, suggesting that the mutation responsible for the E13GB42 phenotype influences multiple genetic factors that control fruit pigmentation.

[EN] The response of two Citrullus amarus accessions, BGV0005164 and BGV0005167, was assessed against different Meloidogyne arenaria, Meloidogyne incognita, and Meloidogyne javanica isolates in pot experiments and against M. incognita in plastic greenhouse. In the pot experiments, plants were inoculated with a second-stage juvenile per cm(3) of sterile sand and maintained in a growth chamber at 25 degrees C for 50 days. The watermelon cv. Sugar Baby was included as a susceptible control for comparison. At the end of the experiments, the number of egg masses and eggs per plant was determined, and the reproduction index was calculated as the percentage of the number of eggs produced in the C. amarus accessions with regard to that produced in the susceptible cv. Sugar Baby. In the plastic greenhouse experiment, the ungrafted watermelon cv. Sugar Baby and watermelons grafted onto each of the C. amarus accessions and onto the watermelon rootstock cv. Robusta were cultivated from May to August 2016 in plots with nematode densities from 46 to 1392 J2 per 250 cm(3) of soil at transplantation. At the end of the experiment, the galling index and the number of eggs per plant were determined, and the reproduction index was calculated. Additionally, the compatibility of the two accessions with the watermelon cv. Sugar Baby and the effect on fruit quality (weight, size, shape, firmness, pH, total soluble solids, and flesh color) were assessed under a hydroponic system in a greenhouse. The commercial rootstocks cv. Cobalt and cv. Robusta were also included. All the Meloidogyne isolates produced less egg masses and eggs per plant on the accessions than on Sugar Baby. Both accessions performed as resistant against M. arenaria, and from highly to moderately resistant to M. incognita and M. javanica in pot experiments. In the plastic greenhouse experiment, both C. amarus accessions performed as resistant to M. incognita. Both C. amarus accessions were compatible with the watermelon cv. Sugar Baby, but only the BGV0005167 accession did not influence the fruit quality. Then, the BGV0005167 accession is a promising rootstock for managing the three tropical root-knot nematode species without influencing watermelon fruit quality., The authors thank MINECO and FEDER for funding projects AGL2013-49040-C2-1-R, AGL2014-53398-C2-2-R-AR, AGL2017-89785-R, and AGL2017-85563-C2-1-R-AR. H. A. Garcia-Mendivil acknowledges CONACYT for suport through a pre-doctoral grant.

[EN] Organogenesis is influenced by factors like genotype, type of explant, culture medium components, and incubation conditions. The influence of ethylene, which can be produced in the culture process, can also be a limiting factor in recalcitrant species like pepper. In this work, bud induction was achieved from cotyledons and hypocotyls-from eight pepper cultivars-on Murashige and Skoog (MS) medium supplemented with 22.2 mu M 6-benzyladenine (6BA) and 5.71 mu M indole-3-acetic acid (IAA), in media with or without silver nitrate (SN) (58.86 mu M), a suppressor of ethylene action. In the SN-supplemented medium, the frequencies of explants with buds and with callus formation were lower in both kinds of explant, but higher numbers of developed shoots were isolated from explants cultured on SN. Bud elongation was better in medium with gibberellic acid (GA(3)) (2.88 mu M) than in medium free of growth regulators or supplemented with 1-aminocyclopropane-1-carboxylic acid (ACC) at 34.5 mu M. However, isolation of shoots was difficult and few plants were recovered. The effect of adding SN following bud induction (at 7 d) and that of dark incubation (the first 7 d of culture) was also assessed in order to improve the previous results. When SN was added after bud induction, similar percentages of bud induction were found for cotyledons (average frequency 89.37% without SN and 94.37% with SN) whereas they doubled in hypocotyls (50% without SN and 87.7% with SN). In addition, in both kinds of explant, the number of developed plants able to be transferred to soil (developed and rooted) was greatly increased by SN. Dark incubation does not seem to improve organogenesis in pepper, and hypocotyl explants clearly represent a better explant choice-with respect to cotyledonary explants-for the pepper cultivars assayed., We thank the COMAV germplasm bank at Universitat Politecnica de Valencia and the Arid Lands Institute for pepper seeds and the Tunisian Ministry of Higher Education and Scientific Research who fund N. Gammoudi's stay.

[EN] Bituminaria bituminosa (L.) C.H. Stirton is a drought tolerant, perennial legume pasture species and a source of pharmaceutical compounds. Bituminaria breeding programs aim to develop and conserve hybrids with desirable traits such as high forage quality, tolerance to biotic or abiotic stresses, and high contents of furanocoumarins. In this work we present a cryopreservation study of different B. bituminosa accessions: two varieties and eight intervarietal hybrids resulting from crosses between the three botanical varieties: var. bituminosa, var. crassiuscula, and var. albomarginata. No previous work on cryopreservation of Bituminaria species has been reported. We applied the ultra-fast cooling method, using droplet vitrification on aluminum foil strips. First, we investigated the PVS2 toxicity and cryopreservation damage in two genotypes, comparing three PVS2 treatments and two culture media. An incubation of 30 min in PVS2 resulted in regeneration rates after cryopreservation higher than 80%. The MS medium was selected for optimal meristem outgrowth, in order to avoid the prominent callus formation that was observed in the presence of BAP. These conditions were subsequently used to cryopreserve eight other genotypes. The results were highly variable; 45 days after cryopreservation, survival ranged between 22% and 98% while regeneration ranged between 0% and 96%, depending on the accession. A significant and positive correlation was observed between survival and regeneration. At 90 days post culture plantlets could be recovered from cryopreserved explants of all genotypes. This study shows that the droplet vitrification method is promising for the cryopreservation of eight of the 10 genotypes assayed and the method can thus be applied to develop a cryobank of B. bituminosa. 2015 Elsevier Inc. All rights reserved., C. Gisbert thanks the Universitat Politècnica de València (PAID-00-10) and the Laboratory of Tropical Crop Improvement of KU Leuven (Belgium), that made these experiments possible. M. Dabauza was co-funded by the European Social Fund (ESF) and Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA). The authors thank IMIDA for providing the germplasm of Bituminaria and the Spanish Ministry of Science and Innovation (MICINN) (Project BFU2010-19599) for providing support. We thank Dr. David Walker for the revision of the written English in the manuscript.

[EN] Background: A protocol for the micropropagation of the grape (Vitis vinifera L.) cultivar 'Monastrell' was developed. Initial plant material was obtained from the sanitary selection of grapevine plants performed by real-time RT-PCR to confirm the absence of Grapevine fanleaf virus, Arabis mosaic virus, Grapevine leafroll-associated virus 1, Grapevine leafroll-associated virus 3, and Grapevine fleck virus. Results: The effects of the salt composition (comparing Lloyd and McCown woody plant medium and Murashige and Skoog medium 1/2 macronutrients) and the growth regulator benzylaminopurine (BAP), at 0 and 8.9 mu M, on plant propagation were evaluated using nodes as explants. The most efficient procedure consisted of bud induction in the medium with Lloyd and McCown woody plant salts and 8.9 mu M BAP for 30 d along with elongation in cytokinin-free medium for 60 d, which gave 22 nodes/explant (174 plants/initial plant). A second cycle of propagation in a medium without BAP for another 60 d could give approximately 10,000 nodes, which can be obtained after an additional 2 months of culture. All plants acclimatized after the second cycle of multiplication were successfully transferred to soil. Conclusion: We developed an optimal protocol for V. vinifera cv. 'Monastrell' micropropagation, the first described for this cultivar. (C) 2017 Pontificia Universidad Catolica de Valparaiso. Production and hosting by Elsevier B. V. All rights reserved., The study was supported by the projects RTA2011-00067-C04, RTA2014-00061-C03, and PRP-CGL2015-70843-R, all co-funded with FEDER Funds. Tania San Pedro has a grant (01/14-FSE-22) supported by the Instituto Valenciano de Investigaciones Agrarias.

The authors also thank the MINECO projects AGL2013-49040-C2-1-R and AGL2014-53398-C2-2-R, cofunded with FEDER funds.

The accession Solanum peruvianum PI 126944 has been reported as resistant to different biotic and abiotic stresses. In previous works of the group, advanced generations were derived from two interspecific hybrids, including up to pseudo-F6 generations and backcrosses to the cultivated species of some of the pseudo-Fn generations. Moreover, resistance to Tomato yellow leaf curl virus (TYLCV) and Tomato spotted wilt virus (TSWV) was confirmed in some of the plant materials obtained. Here we describe the development of some advanced backcross generations between the cultivated tomato and S. peruvianum. Three backcross assays were carried out. In the first assay, 16 plants belonging to pseudo-F4, pseudo-F5 and pseudo-F6 generations were backcrossed as male parents to cultivated tomato. Immature seeds from the 408 fruits obtained were platted and 77 plants were regenerated. A total of 21 descendants obtained in the first assay were backcrossed as male parents in the second assay, which allowed the obtaining of 599 fruits and regeneration of 365 plants. The 19 male parents used in the third assay were obtained either in the first or in the second one. Seventeen of them were obtained in the first assay and two in the second. A total of 339 plants were regenerated from 519 fruits. A high number of the plants obtained in these assays has been acclimated. Some plants set fruits with viable seeds.

[EN] Cultivation of Cucumis melo is hampered by soil stresses. Grafting is used to overcome these limitations. Different cucurbits belonging to several genera have been used as rootstocks for melons: Cucurbita, Lagenaria, Luffa, etc. However, negative effects on fruit quality appear in some rootstock-scion combinations. The selection of new resistant rootstocks that do not cause this negative impact in quality is necessary to improve melon cultivation. In this work, we evaluated two rootstocks, closer genetically to melon scions than those usually employed: a) an F1 hybrid between a commercial melon (C. melo subspecies melo var inodorus market class Piel de Sapo) and one exotic accession (C. melo subspecies agrestis var. chinensis) with resistance to Monosporacus cannonballus, the causal agent of melon vine decline, and with a certain level of tolerance to Fusarium oxysporum f sp. melonis race 1.2, that causes Fusarium wilt, and b) an accession of Cucumis metuliferus, highly resistant to M. cannonballus, F. oxysporum 1.2 and evaluated and classified as highly resistant to Meloidogyne spp. in this work. Grafting compatibility of these two selected genotypes with commercial melons was good. All grafted plants displayed higher vigour and earlier flowering than ungrafted plants. Fruits from plants grafted onto C. metuliferus showed similar quality than those from ungrafted/selfgrafted plants. However, fruits from plants grafted onto the F1 (inodorus x chinensis) had in this experiment lower brix degree than the ungrafted controls. The resistance to soil borne pathogens found in C. metuliferus and the good performance regarding plant development and fruit quality of the scions indicate that this species is a promising rootstock for melons., C. Gisbert and B. Pico thanks the Programa Hispano-Brasileno de Cooperacion Universitaria PHBP14/00021. Authors also thank the MINECO projects AGL2013-49040-C2-1-R, and AGL2014-53398-C2-2-R, cofunded with FEDER funds.

[EN] Introduction. Interest in grafting onto rootstocks resistant to soil-borne pathogens has risen since the phasing-out of methyl bromide, an efficient soil disinfectant. In this study, we have evaluated the putative effect of rootstock¿scion combinations on pepper fruit nutritional quality in relation to grafting, an effect that is sometimes overlooked. Materials and methods. As the scions, we used two representative sweet pepper cultivars, `Almuden¿ and `Coyote¿, and as rootstocks `Foc¿ and `Charlot¿, both resistant to Phytophthora capsici and Meloidogyne incognita. Dry matter, soluble solids, proteins, phenolics, and vitamin C content, as well as eight minerals (P, K, Ca, Mg, Na, Fe, Cu, and Zn) were measured in fruits from non-grafted, self-grafted, and grafted plants. Results and discussion. Differences in the fruit composition were found, depending on the genotype, rootstock, or rootstock¿scion combination. The main effects were as follows. Higher values of ¿Brix, phenolics, P, Mg, and Na were found in the fruit of `Coyote¿ whereas the vitamin C and Fe levels were higher in `Almuden¿ fruit. The dry matter, protein, and K concentrations were higher in the fruit from grafted plants with respect to the values from non-grafted plants, especially in the fruit from plants grafted onto `Charlot¿ and `Foc¿ rootstocks (increases of 11.8%, 17.6%, and 9.6%, respectively; when average values of the four combinations of these rootstocks). Fruit from `Almuden¿ and `Coyote¿ plants grafted onto the rootstock `Foc¿ had lower ¿Brix values (about one degree less than the control) and lower values of phenolics were also obtained when used this rootstock (14.4% less than for the control). On the other hand, the P concentration was higher in the fruit of `Coyote¿ grafted onto `Charlot¿ (17.2% higher than for the control). This combination also exhibited the highest fruit K concentration (226.70 mg 100 g¿1 fresh weight). Conclusion. From a nutritional point of view it is important to evaluate and select the best rootstock¿scion combinations: in our assay, this was `Charlot¿¿`Coyote¿ the fruit of which showed the highest ¿Brix and K, P, and protein concentrations., This work was funded by the Fundacion Agroalimed (supported by the Valencian regional government - the Comunidad Valenciana). We thank Dr. David Walker for the revision of the written English in the manuscript

[EN] The influence of ethylene and ethylene modulators on the in vitro organogenesis of tomato was studied using a highly regenerating accession of the wild tomato Solanum pennellii and an F1 plant resulting from a cross between Solanum pennellii and Solanum lycopersicum cv. Anl27, which is known to have a low regeneration frequency. Four ethylene-modulating compounds, each at four levels, were used, namely: cobalt chloride (CoCl 2), which inhibits the production of ethylene; AgNO 3 (SN), which inhibits ethylene action; and Ethephon and the precursor 1-aminocyclopropane-1-carboxylic acid (ACC), which both promote ethylene synthesis. Leaf explants of each genotype were incubated on shoot induction medium supplemented with each of these compounds at 0, 10 or 15 days following bud induction. The results obtained in our assays indicate that ethylene has a significant influence on tomato organogenesis. Concentrations of ethylene lower than the optimum (according to genotype) at the beginning of the culture may decrease the percentage of explants with buds (B), produce a delay in their appearance, or indeed inhibit bud formation. This was observed in S. pennellii and the F1 explants cultured on media with SN (5.8-58.0 ¿M) as well as in the F1 explants cultured on medium with 21.0 ¿M CoCl 2. The percentage of explants with shoots (R) and the mean number of shoots per explant with shoots (PR) also diminished in media that contained SN. Shoots isolated from these explants were less developed compared to those isolated from control explants. On the other hand, ethylene supplementation may contribute to enhancing shoot development. The number of isolable shoots from S. pennellii explants doubled in media with ACC (9.8-98.0 ¿M). Shoots isolated from explants treated with ethylene releasing compounds showed a higher number of nodes when ACC and Ethephon were added at 10 days (in F1 explants) or at 15 days (in S. pennellii) after the beginning of culture. Thus, the importance of studying not only the concentration but also the timing of the application of regulators when developing regeneration protocols has been made manifest. An excess of ethylene supplementation may produce an inhibitory effect, as was observed when using Ethephon (17.2-69.0 ¿M). These results show the involvement of ethylene in tomato organogenesis and lead us to believe that ethylene supplementation may contribute to enhancing regeneration and shoot development in tomato. © 2012 Springer Science+Business Media B.V., Carlos Trujillo has a predoctoral fellowship from the Spanish 'Ministerio de Educacion y Ciencia'. This work has been funded by Universitat Politecnica de Valencia (PAID 05-10). The technical assistance of N. Palacios and the revision of the manuscript's English by J. Bergen are gratefully acknowledged.

7 pages, 2 figures, 1 table, 19 references. Trabajo incluido en el Capítulo: Seed Genetics and Biotechnology, an Seed Germination and Vigour, presentado al Fith International Symposium on Seed, Transplant and Stand Establishment of Horticultural Crops, celebrado del 27/09 al 1/10 de 2009, en Murcia y Almería, España., Orthodox seeds may present differences in germination due to several reasons. Poor seed germination limits the use of different species for culture or plant breeding. In this work, we tested treatments for improving germination in two cultivars of common eggplant (Solanum melongena) and in six accessions of the related species S. macrocarpon, S. aethiopicum, and S. incanum. With the exception of S. incanum MM- 557, which did not germinate, seeds of the other accessions directly had lower final germination percentages when sown in Petri dishes with deep filter paper than those that were pretreated by surface sterilization and sown in nutrient medium; a further increase in the final germination percentages was achieved by addition of 1 mg L-1 GA3 to the medium. The GA3-pretreatment not only increased the final germination percentages but promoted germination also by reducing germination time. Other treatments included stratification of S. macrocarpon and S. aethiopicum seeds at 4°C for 15 or 30 days, as well as addition of 1 mg L-1 of TDZ and BAP for the BBS-168 accession, but this did not improve germination. The addition of 0.3 mg L-1 fluridone, an inhibitor of carotenoid biosynthesis, that is known to prevent ABA biosynthesis, increased the final germination percentages of S. melongena, S. aethiopicum and S. macrocarpon to a similar degree as GA3. Seeds of S. incanum MM-557 did not respond to this treatment but the hybrid derived from this S. incanum accession with eggplant accession ANS-26 showed high germination percentages (70%, 13 days after sowing) in NM medium with GA3, fluridone or both components. These results show that seed treatments can contrihute to improving germination of Solanum accessions with low germination.

[EN] Genetic variability is needed to face environmental changes and pathogen constrains. In addition, the search for intravarietal variability contributes to the avoidance of genetic erosion, preserving clones that are adapted to particular conditions. Variability is also important to diversify grapevine-derived products. In this work, we have analyzed the genetic variability of `Muscat germplasm¿ including samples from neglected vineyards from Alicante and Valencia provinces, accessions of the germplasm collections of `Colección de Vides de El Encín¿ (Alcalá de Henares, Madrid) and `La Casa de las Vides¿ (Agullent, Valencia), accessions supplied by nurseries of Valencia province, and `Muscat of Alexandria¿ clones selected using differential ampelographic characteristics in selection programs (La Marina, Alicante). Fifteen microsatellites (SSRs) were used to study intervarietal variability. The SSR fingerprinting allowed the identification of some accessions, variants, and synonymies. Amplified Fragment Length Polymorphisms (AFLPs) markers and Microsatellite-AFLPs were used to determine the variability attended in `Muscat of Alexandria¿ accessions. A CAPs (Cleaved Amplified Polymorphic Sequences) marker, recently developed for the discrimination of `Muscat¿ flavor genotypes using the SNP1822 G>T, was assessed and showed that all the analyzed accessions were `Muscat¿ flavored. The variation found among the analyzed germplasm is very interesting because variants within `Muscat of Alexandria¿, `Muscat Italia¿, and `Muscat d¿Istambul¿ have been identified. In addition, intravarietal genetic variation was found among the analyzed accessions in `Muscat of Alexandria¿ from selection programs., MINECO and FEDER Funds (project CGL2015-70843-R); Conselleria d'Agricultura, Pesca i Alimentacio, Generalitat Valenciana, Spain (project 2007TAHALI00073)

Gibberellins are phytohormones that regulate growth and development of plants. Gibberellin homeostasis is maintained by feedback regulation of gibberellin metabolism genes. To understand this regulation, we manipulated the gibberellin pathway in tobacco and studied its effects on the morphological phenotype, gibberellin levels and the expression of endogenous gibberellin metabolism genes. The overexpression of a gibberellin 3-oxidase (biosynthesis gene) in tobacco (3ox-OE) induced slight variations in phenotype and active GA(1) levels, but we also found an increase in GA(8) levels (GA(1) inactivation product) and a conspicuous induction of gibberellin 2-oxidases (catabolism genes; NtGA2ox3 and -5), suggesting an important role for these particular genes in the control of gibberellin homeostasis. The effect of simultaneous overexpression of two biosynthesis genes, a gibberellin 3-oxidase and a gibberellin 20-oxidase (20ox/3ox-OE), on phenotype and gibberellin content suggests that gibberellin 3-oxidases are non-limiting enzymes in tobacco, even in a 20ox-OE background. Moreover, the expression analysis of gibberellin metabolism genes in transgenic plants (3ox-OE, 20ox-OE and hybrid 3ox/20ox-OE), and in response to application of different GA1 concentrations, showed genes with different gibberellin sensitivity. Gibberellin biosynthesis genes (NtGA20ox1 and NtGA3ox1) are negatively feedback regulated mainly by high gibberellin levels. In contrast, gibberellin catabolism genes which are subject to positive feedback regulation are sensitive to high (NtGA2ox1) or to low (NtGA2ox3 and -5) gibberellin concentrations. These two last GA2ox genes seem to play a predominant role in gibberellin homeostasis under mild gibberellin variations, but not under large gibberellin changes, where the biosynthesis genes GA20ox and GA3ox may be more important.

[EN] This paper analyses to what extent, and how, student’s work can be used to improve students’ on-site learning experience and enrich the course evaluation process. The work presented focuses on gathering and analysing different information related to the out-of-class work carried out by students in various Bachelor and Master courses taught at the Universitat Politècnica de València. Results show that there is not a clear relationship between the time devoted to a given task and the attained results, but they highlight especial cases to be considered, like a number of students that devote excessive time to the task but get poor marks. Moreover, the lack of adequate supervision of outof-class work leads to situations where teachers underestimate or overestimate this time. Supervision of student’s outof-class work is thus an essential asset for adequately tuning and improving courses content and scheduling, providing meaningful feedback to students, and rewarding the personal work they invest on tasks, something of major importance for keeping students’ motivation in continuous learning and evaluation processes.

[EN] Within the context of UPV’s project for improving the learning process through innovation, the TASCA group has developed and applied different strategies to assess student’s out-of-class work. This work has allowed us to collect feedback from proposed out-of-class activities, like whether the deadlines for assignments have been under or overestimated, or students’ opinion, to improve thos activities. We have test the usefulness of these strategies in nine different degrees. In general, there is a great variability in the time students devote to a given task and, in some cases, no positive correlation is observed between that time and the obtained results. Hence, by performing this kind of evaluation early in the course it is possible to detect those students that obtained poor marks despite investing a long time in the taks and, provide them meaningful and effective feedback. On the other hand, we monitored the quantity of out-of-class assigments during a year, for a given degree, and we observed that there are different periods of time with a very high concentration of activities. This, obviously, should be avoided. Finally we study how students are perceiving the proposed out-of-class activities and extract information for improving those task and stimulating students’ motivation and paticipation. In this work we present these results and their analysis., [ES] En el marco de los proyectos de innovación y mejora educativa promovidos por la UPV, el grupo TASCA ha desarrollado y aplicado distintas estrategias con el fin de realizar un seguimiento del trabajo no presencial que se asigna a los alumnos. Así es posible determinar la adecuación del tiempo asignado a las tareas no presenciales, obtener información sobre la actividad realizada y la opinión del alumno, con el fin de ejercer retroalimentación y mejora en las actividades propuestas. Se han elaborado distintos cuestionarios con el fin de poder abordar los objetivos propuestos en nueve titulaciones. La estimación del tiempo dedicado al trabajo no presencial ha reflejado una gran la variabilidad entre los alumnos y no siempre se ha encontrado correlación positiva entre el tiempo invertido y la calificación obtenida. Este resultado nos ha llevado a implementar este tipo de evaluación en etapas tempranas del curso con el fin de poder efectuar una retroalimentación en los alumnos que, invirtiendo más tiempo que la media, no obtienen buena calificación. Por otra parte, el seguimiento en distintas etapas del curso nos ha indicado que se producen ciertos picos de trabajo no presencial que podrían saturar al alumno y que convendría evitar. Las respuestas a las cuestiones planteadas y la opinión de los alumnos sobre las actividades efectuadas nos ha ayudado a mejorar las actividades propuestas y a estimular la participación de los mismos. En este artículo se presentan los seguimientos realizados y sus resultados., Este trabajo ha sido desarrollado en el marco del proyecto PIME/2014/A/022/A “Análisis del trabajo no presencial para la retroalimentación alumno-profesor (Renovación del PIME A08/13)” financiado por la Universitat Politècnica de València.

The conservation of old grapevine varieties is important since they are adapted to specific climate conditions and may carry genes interesting to breeders. As virus infection is common in grapevine varieties, the use of virus free materials is of great importance. In this work, we used somatic embryogenesis for the sanitation of GLRaV-1 and GLRaV-3 viruses that were found after analyzing the putative presence of the five most common, economically important grape viruses by real-time multiplex RT-PCR in the old cultivar Grumet Negre . Unopened and opened inflorescences, fecundated ovaries, and, also, mature seeds were used as starting explants. Explants were cultured on plates with two embryogenesis induction media (Nitsch & McCown Woody plant medium) that contained the growth regulator thidiazuron and differed in their salt and vitamin compositions. One half of each kindof explant was cut prior to being cultured. After five months of culture, embryos had only developed from seeds that were cut previous to sowing. To the best of our knowledge, this is the first time that mature seeds have been used for inducing embryogenesis in grape. A total of 42% of the embryos transferred to tubes for germination regenerated into normal plantlets. The absence of both the GLRaV-1 and GLRaV-3 viruses in all regenerated plants was confirmed by real-time uniplex RT-PCR. So, this protocol can be used for sanitation and also for micropropagation., This work was supported by the INIA RTA2011-00067-C04-04 and RTA2011-00067-C04-01 projects co-funded with FEDER funds.

9 pages, 2 figures, 7 tables., Cultivation of crops in or close to contaminated sites may result in both growth inhibition and tissue accumulation of heavy metals, with resulting possible risks to humans or livestock health if these tissues are ingested. In this work, growth inhibition and accumulation of Cd, Cu, Pb and Zn for three Brassica crop species (B. oleracea L., B. carinata A. Br. and B. juncea (L.) Czern.) and the autochthonous Cu-accumulating species Hirschfeldia incana (L.) Lagrèze-Fossat were studied, in two contaminated soils from the Murcia region of Spain and one from Valencia, over a 80-day period (40 days for H. incana) in pot experiments. Growth parameters indicated a tolerance index averaged for the two contaminated soils (relative to non-contaminated substrate) of the Brassica species in the order: B. juncea (mean value 97.6%) > B. carinata cv. 117 (74.2%) > B. carinata cv. 2920 (66.5%) ≈ B. oleracea (65.6%), with an average of 72% for H. incana. Above-ground tissue metal concentrations indicated a possible risk to human and livestock health from Cd and Pb for B. oleracea and H. incana. H. incana did not show a marked shoot accumulation of Cu, possibly due to inhibition of Cu uptake by the high soil levels of Zn and Pb. Its shoot tissue concentrations of Pb and Zn were related more closely to the total soil metal concentrations than to the DTPA-extractable, concentrations of these elements., This work was financed by the Spanish Ministry of Science and Technology and the EU through FEDER funds (refs: 1FD97-1469-C04-01 and -02).

The scarlet (Solanum aethiopicum) and gboma (S. macrocarpon) eggplants are two African crops with potential for vegetable crop diversification in subtropical climates. Here we carried out the in vitro regeneration in two accessions of each species. In a comparison of five media, we found that those containing the cytokinin thidiazuron (TDZ) induced the greatest regeneration response from both cotyledonary and true leaf explants. After organogenesis induction, explants were transferred to Murashige & Skoog (MS) basal medium without growth regulators for 20 days. Isolated shoots rooted after culture on MS medium for 4–6 days. Optimisation of TDZ concentration was studied in a range of concentrations from 0.05 to 0.8 μM. In general, increases in the concentration of TDZ in the medium resulted in a higher density of buds, but they had a slower development. Although differences in regeneration ability were observed among varieties, TDZ concentrations of 0.1 or 0.2 μM gave the best results, with 70–100...

Hybrids of Solanum melongena and S. aethiopicum are of interest as rootstocks of eggplant, as they are highly vigorous and can incorporate resistance to several diseases. However, hybridization between both species is difficult. Therefore, protocols for in vitro culture are of great interest for their micropropagation and biotechnological breeding. We assessed the organogenesis response from leaf explants in four interspecific hybrids and in their parents testing two organogenic media: SIM-A, containing 6-benzylaminopurine and kinetin, and SIM-B, which contains thidiazuron. A higher regeneration capacity in the hybrids compared to their parents was observed. Whereas in interspecific hybrids and in one accession of S. melongena similar regeneration rates were observed for SIM-A and SIM-B, higher regeneration was found in the rest of genotypes when thidiazuron was used. Rooting ability in the interspecific hybrids was lower in in vitro micropropagated plants (35-60%) than in plants regenerated from explants (100%). The addition of indolbutiric acid (1 mg L-1) induced roots in nonrooted genotypes. In summary, we have adjusted in vitro culture conditions for regenerating and rooting S. melongena x S. aethiopicum hybrids. We have also demonstrated that these hybrids are heterotic for regeneration, which may be of interest for basic science studies., This work has been partially funded by Universitat Politecnica de Valencia (Grant PAID05-10) and by Ministerio de Economia y Competitividad (Grant AGL2012-34213). Authors thank Dr. John R. Stommel (ARS-USDA, Beltsville, MD, USA) for providing the seeds of the S. melongena M1 and M2 and S. aethiopicum A1 and A2 accessions and the interspecific hybrids used in this work.

The yeast HAL1 gene facilitates K+/Na+ selectivity and salt tolerance of cells. Ectopic expression of HAL1 in transgenic tomato (Lycopersicon esculentum Mill.) plants minimized the reduction in fruit production caused by salt stress. Maintenance of fruit production by transgenic plants was correlated with enhanced growth under salt stress of calli derived from the plants. The HAL1 transgene enhanced water and K+ contents in both leaf calli and leaves in the presence of salt, which indicates that HAL1 functions in plants using a similar mechanism to that in yeast, namely by facilitating K+/Na+ selectivity under salt stress.

SummaryThis paper reports on protocols for in vitro plant regeneration, gene transfer and on shoot salt tolerance from two accessions of L. cheesmanii (Riley). Shoot organogenesis was achieved on media with zeatin or BA/IAA combinations. The two accessions tested, LA1401 and LA530, showed differences in both their aptitude to regenerate and their salt tolerance in vitro. The accession LA530 had a higher organogenic potential than LA1401 (97% vs. 80% of organogenic explants). In contrast, none of the LA530 isolated shoots rooted when cultured in full strength MS-modified medium supplemented with 200.mM NaCl while 93% of shoots from LA1401 formed roots. Finally, Agrobacterium-mediated transformation was used to introduce the nptII and uidA marker genes into the salt tolerant accession LA1401. Eight to nine per cent of the cotyledon explants produced transgenic plants. After self-pollination, the inheritance analysis showed a Mendelian segregation of both transgenes. The collection of transgenic plants will ...

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 geneHAL1 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 theHAL1 gene on salt tolerance may be similar in transgenic plants and yeast.

Agrobacterium -mediated transformation has been used to introduce the yeast halotolerant HAL2 as well as the npt II and uid A marker genes into tomato ( Lycopersicon esculentum ) cv. UC82B. Five to six percent of the explants produced transgenic plants. HAL2 expressing transformants were allowed to self-pollinate and salt tolerance assays were performed in vitro on progenies from two independent transgenic plants with different levels of expression of the transgene. In vitro salt tolerance was evaluated according to the level of growth of hypocotyl-derived calli as well as the rooting capability of isolated shootlets on MS-modified medium supplemented with NaCl. Under salt stress, callus formation from hypocotyl explants was higher on both transgenic-derived progenies than in the control. In addition, progenies from the plant with the highest expression of the transgene (2H20b), also showed a higher level of root production on NaCl-supplemented medium. These results suggested a positive effect of the yeast HAL2 gene on the level of salt tolerance in progenies derived from transgenic plants.

In this work, we have evaluated the host suitability of 29 pepper genotypes of Capsicum annuum and 9 of the related cultivated species C. chinense (4), C. frutescens (4) and C. pubescens (1) to Meloidogyne incognita in field conditions. The presence/absence of resistance genes in the pepper germplasm were also assessed using PCR-specific markers linked to the N, Me1-Mech2, Me3-Me4 and Me7-Mech1 genes. Intraspecific variability for M. incognita resistance was found. According to gall index (GI) and reproduction index (RI) the most resistant genotypes, which may contribute to nematode management, include three of C. frutescens (Fru-2, Fru-3 and Fru-4) and seven of C. annuum (Ca-3, Ca-4, Ca-5, Ca-11, Ca-15, Ca-24 and Ca-25). No egg masses or eggs were found in Fru-3 and Fru-4 genotypes as occurred in the resistant controls ‘SCM’, ‘CH’ and ‘Charlot’. The amplification of markers linked to resistance genes in genotypes with a suitable degree of resistance, together with the differences found between genotypes with regard to the gene and/or number of amplified markers, make this germplasm a valuable tool for further characterisation and pepper breeding.

This work has been funded by Universitat Politècnica de València (PAID 05-10).