María José Díez - Academia.edu (original) (raw)

Papers by María José Díez

Frontiers in Plant Science

The agricultural scenario of the upcoming decades will face major challenges for the increased an... more The agricultural scenario of the upcoming decades will face major challenges for the increased and sustainable agricultural production and the optimization of the efficiency of water and fertilizer inputs. Considering the current and foreseen water scarcity in several marginal and arid areas and the need for a more sustainable farming production, the selection and development of cultivars suitable to grow under low-input conditions is an urgent need. In this study, we assayed 42 tomato genotypes for thirty-two morpho-physiological and agronomic traits related to plant, fruit, and root characteristics under standard (control) and no-nitrogen fertilization or water deficit (30% of the amount given to non-stressed trials) treatments in two sites (environments), which corresponded to organic farms located in Italy and Spain. A broad range of variation was found for all traits, with significant differences between the applied treatments and the cultivation sites. Dissection of genotypic ...

Agronomy, 2022

Traditional vegetable varieties constitute an important reservoir of biodiversity, so recovering,... more Traditional vegetable varieties constitute an important reservoir of biodiversity, so recovering, cultivating, and correctly classifying these landraces is part of key global heritage for the future of food security. In this study, 17 traditional pepper varieties from the Valencian Community (Spain) were characterized using 14 quantitative and 30 qualitative conventional morphological descriptors, including plant, flower, and fruit traits, in two ripening stages: green and red. As a result, landraces were grouped based mainly on their fruit morphology (G1: thin and elongated; G2: thick and robust; P-49: ball pepper). During a second trial, the preservation of the described characteristics was checked, and the number of fruit produced per plant was determined. From the acquired information, the most desirable traits that could be of interest for cultivation and harvesting practices were established, including erect growth habit, dense branching, big leaves, and uniformity and low per...

Phytopathologia Mediterranea, 2017

Tomato yellow leaf curl virus (TYLCV) is the most widespread virus species causing Tomato yellow ... more Tomato yellow leaf curl virus (TYLCV) is the most widespread virus species causing Tomato yellow leaf curl disease. Accurate methods for assessment of resistance are requisite in breeding programs. Researchers at the Volcani Center (Israel) developed a scale of differential TYLCV reactions in seven non-segregating tomato host lines, with virus responses ranging from susceptible to highly resistant. In the present work, this scale has been evaluated with inoculation and assessment methods routinely used by two different research groups, in Spain and Cuba. Different TYLCV isolates, inoculation methods, plant ages, and environmental conditions were compared. Symptom scores of the tomato lines were generally lower in the conditions assayed in both locations than those originally described. Reaction ranking order of the standard tomato lines was more similar to the original description in the assays carried out in Spain. However, response of the lines to TYLCV obtained in both locations ...

Agronomy, 2019

The dramatic reduction in the diversity of crops in the last century is often attributed to the c... more The dramatic reduction in the diversity of crops in the last century is often attributed to the consolidation of scientific breeding, probably because the two processes have occurred at the same time. We carried out a breeding program to enhance the Castellfollit del Boix landrace of common bean (Phaseolus vulgaris L.) in a low-input environment to determine the effects of breeding on a landrace at risk of disappearing. The program increased the number of accessions conserved ex situ and obtained more efficient genotypes that are less likely to be abandoned by farmer without altering the characteristics that consumers appreciate most. As a result, the availability of the product, its promotion, and its use have increased. We propose a Conservation Potential Index to measure the impact of changes in the crop’s epiphenotype, and also apply it to a set of landraces from several crops. We argue that scientific breeding and information gathered in the context of genetic improvement progr...

Frontiers in Plant Science, 2019

Single primer enrichment technology (SPET) is a new, robust, and customizable solution for target... more Single primer enrichment technology (SPET) is a new, robust, and customizable solution for targeted genotyping. Unlike genotyping by sequencing (GBS), and like DNA chips, SPET is a targeted genotyping technology, relying on the sequencing of a region flanking a primer. Its reliance on single primers, rather than on primer pairs, greatly simplifies panel design, and allows higher levels of multiplexing than PCR-based genotyping. Thanks to the sequencing of the regions surrounding the target SNP, SPET allows the discovery of thousands of closely linked, novel SNPs. In order to assess the potential of SPET for high-throughput genotyping in plants, a panel comprising 5k target SNPs, designed both on coding regions and introns/UTRs, was developed for tomato and eggplant. Genotyping of two panels composed of 400 tomato and 422 eggplant accessions, comprising both domesticated material and wild relatives, generated a total of 12,002 and 30,731 high confidence SNPs, respectively, which comprised both target and novel SNPs in an approximate ratio of 1:1.6, and 1:5.5 in tomato and eggplant, respectively. The vast majority of the markers was transferrable to related species that diverged up to 3.4 million years ago (Solanum pennellii for tomato and S. macrocarpon for eggplant). Maximum Likelihood phylogenetic trees and PCA outputs obtained from the whole dataset highlighted genetic relationships among accessions and species which were congruent with what was previously reported in literature. Better discrimination among domesticated accessions was achieved by using the target SNPs, while better discrimination among wild species was achieved using the whole SNP dataset. Our results reveal that SPET genotyping is a robust, high-throughput technology for genetic fingerprinting, with a high degree of cross-transferability between crops and their cultivated and wild relatives, and allows identification of duplicates and mislabeled accessions in genebanks.

Nature Genetics, 2019

Modern tomatoes have narrow genetic diversity limiting their improvement potential. We present a ... more Modern tomatoes have narrow genetic diversity limiting their improvement potential. We present a tomato pan-genome constructed using genome sequences of 725 phylogenetically and geographically representative accessions, revealing 4,873 genes absent from the reference genome. Presence/absence variation analyses reveal substantial gene loss and intense negative selection of genes and promoters during tomato domestication and improvement. Lost or negatively selected genes are enriched for important traits, especially disease resistance. We identify a rare allele in the TomLoxC promoter selected against during domestication. Quantitative trait locus mapping and analysis of transgenic plants reveal a role for TomLoxC in apocarotenoid production, which contributes to desirable tomato flavor. In orange-stage fruit, accessions harboring both the rare and common TomLoxC alleles (heterozygotes) have higher TomLoxC expression than those homozygous for either and are resurgent in modern tomatoes. The tomato pan-genome adds depth and completeness to the reference genome, and is useful for future biological discovery and breeding.

HortScience, 1999

Seedlings of three tomato (Lycopersicon esculentum Mill.) cultivars [`RDD', carrier of the Sw... more Seedlings of three tomato (Lycopersicon esculentum Mill.) cultivars [`RDD', carrier of the Sw5 gene, which confers resistance to tomato spotted wilt virus (TSWV); `Pitihué', tolerant to the virus; and the susceptible cultivar Rutgers] were placed at the four- to five-leaf stage in cages containing a population of viruliferous thrips (Frankliniella occidentalis Perg.), and remained there for 0, 7, or 15 days. Plants were subsequently transplanted either into the open field or in tunnels protected with a mesh of 14 × 10 threads/cm. Systemic symptoms and number of dead plants were recorded and enzymelinked immunosorbent assays (ELISA) were performed. `Rutgers' exhibited severe systemic symptoms regardless of treatment and a high number of plants died. The level of infected plants remained low when protective measures were applied to seedlings of `Pitihué' and acceptable yields were obtained. In open air cultivation, where seedling infection was severe, <20% of `RDD...

Euphytica, 2017

The need to boost agricultural production in the coming decades in a climate change scenario requ... more The need to boost agricultural production in the coming decades in a climate change scenario requires new approaches for the development of new crop varieties that are more resilient and more efficient in the use of resources. Crop wild relatives (CWRs) are a source of variation for many traits of interest in breeding, in particular tolerance to abiotic and biotic stresses. However, their potential in plant breeding has largely remained unexploited. CWRs can make an effective contribution to broadening the genetic base of crops and to introgressing traits of interest, but their direct use by breeders in breeding programs is usually not feasible due to the presence of undesirable traits in CWRs (linkage drag) and frequent breeding barriers with the crop. Here we call for a new approach, which we tentatively call 'introgressiomics', which consists of mass scale development of plant materials and populations with introgressions from CWRs into the genetic background of crops. Introgressiomics is a form of

Phytoma Espana La Revista Profesional De Sanidad Vegetal, 2013

INTED2016 Proceedings, 2016

Scientia Agricola, 2015

Despite the importance of traditional varieties of tomato (Solanum lycopersicum L.) as sources of... more Despite the importance of traditional varieties of tomato (Solanum lycopersicum L.) as sources of variation in breeding programs and varieties targeted to high-price quality markets that value their exceptional organoleptic quality, little is known regarding the structure of these materials at the morphological level. In this study, a collection of 166 populations (137 of them during two years) of traditional varieties of tomato from the east coast of Spain has been characterized using 41 descriptors. The characterization revealed a considerable variation. The segregation observed in several populations (28 %) suggests that apart from the configuration as population varieties, the high variation present in these landraces may be partially due to possible seed mixing and spontaneous cross-pollination. Only nine fruit descriptors were required to represent the variation present in the collection analyzed. It seems that after spontaneous crosspollinations, farmers applied strong selection to a small number of traits, though even in these traits a high level of variation is maintained. The variation observed may hinder clear recognition by the consumer, an attribute required for the consolidation of quality markets. Additionally, a registry of these materials as conservation varieties would be complicated considering the actual levels of variation. Therefore, a varietal depuration would be interesting in order to promote in situ conservation of these resources. Finally, the high levels of variation in the intra-varietal scale may justify the collection and maintenance of more populations of the same variety as the risk of conserving duplicates would not be so high.

The breeding line UPV 1 developed from the PE-18 accession of Lycopersicon peruvianum collected i... more The breeding line UPV 1 developed from the PE-18 accession of Lycopersicon peruvianum collected in Huallanca, Ancash, Peru, shows resistance to TSWV. Mechanical inoculation and thrips transmission were used to study the inheritance of TSWV resistance of this line. UPV 1 resistance is controlled by a dominant gene. The penetrance of this resistance gene was complete in mechanical inoculation and incomplete when thrips transmission was used. Linkage tests between the resistance genes of lines UPV 1 and RDD (Sw-5), indicated allelism. A molecular analysis using a SCAR marker tightly linked to Sw-5 also supported this hypothesis. In heterozygotes the level of resistance expressed in UPV 1 is higher than that expressed in RDD (Sw-5), indicating that the resistance from UPV 1 may be of higher value for the development of commercial hybrids.

Spanish Journal of Agricultural Research, 2003

Tomato spotted wilt virus (TSWV) is among the ten most important plant viruses and annual losses ... more Tomato spotted wilt virus (TSWV) is among the ten most important plant viruses and annual losses attributed to this virus have been estimated to be around 1,000 million dollars (Goldbach and Peters, 1994). The disease was first detected in Spain in 1989 (Cuadrado et al., 1991). In our country, damage to tomato crops is especially important along the coast of Catalonia where the proportion of infected plants in commercial crops can exceed 50% (

Journal of Phytopathology, 2002

Pepino mosaic virus (PepMV), a potexvirus ®rst described in 1980 from pepino (Solanum muricatum) ... more Pepino mosaic virus (PepMV), a potexvirus ®rst described in 1980 from pepino (Solanum muricatum) plants cultivated in Peru, was isolated from diseased tomato plants in the Netherlands in 1999, and is now the cause of an emerging tomato disease in Europe. In a survey of central and southern Peru, 65 wild and four cultivated populations of Lycopersicon, as well as six populations of other species of Solanaceae, were tested for the presence of PepMV and six other viruses. Of the Lycopersicon population sampled, 23 (35.4%) reacted positively in double antibody sandwich (DAS)-enzymelinked immunosorbent assay (ELISA) with antisera to PepMV. DAS-ELISA tests for PepMV of other solanaceous species were negative, except for one sample of pepino (Solanum muricatum). Mechanical inoculation of susceptible Lycopersicon esculentum cv. NE-1 plants with crude sap extracts of 20 of these samples con®rmed that 15 of them (from the Departments of Apurimac, Arequipa and Moquegua) were infected with PepMV; these inoculated plants were also DAS-ELISA positive and, in most cases, developed symptoms. Thirteen of the infective extracts were obtained from plants of wild Lycopersicon species (three L. chilense, three L. chmielewskii, two L. parvi¯orum and ®ve L. peruvianum) and one each from the cultivated species L. esculentum and S. muricatum. The wild Lycopersicon species are newly reported natural hosts of PepMV. Tests for the other six viruses were negative, except that two samples contained Tomato mosaic virus. Thus, PepMV occurs in Lycopersicon species in central and southern Peru, even in isolated wild populations. These results indicate that the virus is not new to the region and has an ecient mechanism of natural transmission.