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Se evaluó la variabilidad genética para la vida postcosecha y el peso de los frutos en veintiséis familias F3 de un híbrido interespecífico entre la cv. Caimanta de Lycopersicon esculentum Mill. y la línea LA722 de L. pimpinellifolium (Jusl.) Mill. con el objeto de obtener genotipos divergentes para ambos caracteres. Los promedios de días de vida postcosecha fueron 8, 15, 18 y 13 y de peso en gramos fueron 52,17, 0,94, 4,45 y 6,41 para cv. Caimanta, LA722, la F1 y la generación F3, respectivamente. Ninguna familia fue similar al progenitor `Caimanta' para el carácter días de vida postcosecha y sólo una familia tuvo una vida postcosecha como la F1. Para el peso de los frutos, cuatro familias fueron similares a la F1 y ninguna fue como los progenitores. La familia con peso de los frutos con 20,15 g y vida postcosecha de 21,5 días fue la que presentó mayores valores. El menor peso de los frutos fue en una familia con 2,81 g y el de menor vida postcosecha en una con 9,98 días. La amplia variabilidad genética encontrada para ambos caracteres entre las familias permitirá obtener genotipos divergentes.

Plant resistance (R) genes tend to be highly variable within plant species and are thought to be under natural selection; however, little is known about the geographic distribution of R gene diversity within and among plant populations. To determine the possible roles of demography and selection on R gene evolution, patterns of diversity at the multigenic Cf-2 R gene family were studied in Solanum pimpinellifolium populations along the northern coast of Peru. Population diversity levels of Cf-2 homologs follow a latitudinal dine, consistent with the species's history of gradual colonization of the Peruvian coast and population variation in out-crossing levels. Although previous evidence suggests that selection has shaped the DNA sequence content of the Cf-2 genes, current results imply that the geographic distribution of cf-2 homolog diversity has been shaped primarily by demographic factors or by selective pressures with a clinal distribution. [ABSTRACT FROM AUTHOR]

Abstract: The wild tomato species Lycopersicon pimpinellifolium (currant tomato) was exposed to different O3 concentration, both in controlled environment fumigation facilities and in open-top chambers, to assess its sensitivity and to verify its potential as a bioindicator plant. Plants appeared particularly sensitive to O3 at an early stage of growth, responding with typical chlorotic spots within 24h after exposure to a single pulse of 50ppb for 3h, and differentiating peculiar symptoms, such as reddish necrotic stipples, bronzing and extensive necrosis, depending on O3 concentration. Histo-cytochemical investigations with 3,3′-diaminobenzidine, to localize H2O2, and Evans blue, to detect dead cells, suggested that currant tomato sensitivity to O3 could be due to a deficiency in the anti-oxidant pools. The combination of these stainings proved to be useful, either to predict visible symptoms, early before their appearance, and to validate leaf ozone injury. [Copyright &y& Elsevier]

The characterization of Lycopersicon germplasm for internal quality properties is essential to choose suitable donor parents for breeding programs. When donor parents belong to species of subgenus Eulycopersicon, which are phyletically closer to L. esculentum Mill., the recovery of agronomic traits is faster. When using these materials, a careful selection of donor parents which could improve several internal quality properties allows the acceleration of these breeding programs. In this work, we combine general determinations, such as soluble solid content, titratable acidity, pH, total sugars, pectic substances and total protein contents with precise high-performance liquid chromatography (HPLC), quantitations of individual compounds (vitamin C; citric, malic, fumaric and oxalic acids; glucose, fructose, and sucrose), in order to obtain a more complete characterization of flavor intensity and nutritional properties in Lycopersicon germplasm. The multidimensional analysis of all these variables allows classification of several accessions of L. esculentum Mill. and L. pimpinellifolium (Jusl.) Mill., according to their usefulness for internal quality breeding programs of fresh tomato. The classification obtained and the comparison of accessions quality characteristics with selected controls show that five of the L. pimpinellifolium (Jusl.) Mill. accessions tested can be of great usefulness for being used in breeding for internal quality characteristics. A flavor intensity ≈625 % higher than commercial hybrids was obtained in the best accession tested. Some of these L. pimpinellifolium (Jusl.) Mill. accessions showed better flavor intensity properties than a high SSC L. cheesmanii Riley control, traditionally used in internal quality breeding. In addition, three of the L. esculentum Mill. accessions tested with medium-to-high flavor intensity value could be useful in advanced stages of breeding programs. [ABSTRACT FROM AUTHOR]

Seed of BC1 progeny of an interspecific cross between a slow germinating Lycopersicon esculentum breeding line (NC84173; maternal and recurrent parent) and a fast germinating L. pimpinellifolium accession (LA722) were evaluated for germination under cold stress, salt stress and drought stress, and in each treatment the most rapidly germinating seeds (first 2%) were selected. Selected individuals were grown to maturity and self-pollinated to produce BC1S1 progeny families. The selected BC1S1 progeny from each experiment were evaluated for germination rate in each of a nonstress (control), cold-, salt- and drought-stress treatment, and their performances were compared with those of a nonselected BC1S1 population in the same treatments. Results indicated that selection for rapid seed germination in each of the three stress treatments was effective and significantly improved progeny germination rate under all three stress conditions. The results support the suggestion that same genes might control the rate of seed germination under cold, salt and drought stress. Furthermore, selection in each of the three stress treatments resulted in improved progeny seed germination rate under nonstress conditions, suggesting that genetic mechanisms that facilitate rapid seed germination under stress conditions might also contribute to rapid germination under nonstress conditions. In practice, therefore, selection for rapid seed germination under a single stress environment may result in progeny with improved seed germination under a wide range of environmental conditions. Furthermore, to improve germination rate under nonstress conditions, it might be more efficient to make selections under stress conditions. [ABSTRACT FROM AUTHOR]

Summary • The presence and distribution of invertase is reported in two red fruited and hexose accumulating species of tomato, Lycopersicon esculentum and L. pimpinellifolium , which differ markedly in fruit invertase activity. • Using antibodies raised against a highly conserved invertase peptide, all invertase isoforms in green and red tomato fruit were detected and visualized by chemi luminescence and western blotting techniques. Interacellular localization of invertase was examined by electron and light microscopy. • Invertase activities were much lower in green fruit than in red fruit from all cultivars. However, invertase protein was evenly distributed between all tissues of green and red fruit in tissue blots that had been extensively treated with preimmune serum that eliminated all non-specific binding. Immuno-gold labelling showed that invertase protein was present in the cell wall and vacuole, but not in the cytosol, of epidermal tissue from both species. • Invertase protein is present throughout fruit development in tomato. However, the increase in activity during ripening is due to changes in the activation state of the protein rather than the amount of protein present. [ABSTRACT FROM AUTHOR]

ABSTRACT The soluble and calmodulin (CaM)-dependent NAD+ kinase from Lycopersicon pimpinellifolium was previously shown to be largely inactivated in isolated cells exposed to a short-term NaCl stress (Delumeau, Morère-Le Paven, Montrichard, Laval-Martin (2000) Plant Cell & Environment 23, 329–336). Nevertheless, the activity could be restored by adding a high dithiothreitol concentration to the protein extract, suggesting that the salt stress triggers an oxidation of the enzyme which leads to its inactivation. It was then interesting to investigate the effect of thiol-modifying reagents and disulphide reductants on the activity of L. pimpinellifolium NAD+ kinase. A three-step purification procedure was then established and allowed isolation of the enzyme which exists under two forms: a monomer and a dimer of a 56 kDa subunit, characterized, respectively, by pIs of 6·8 and 7·1. Isolated NAD+ kinase had a high affinity for CaM, half saturation being obtained for 7 ng mL-1 bovine CaM. The activity of NAD+ kinase was strongly inhibited by thiol-modifying reagents and oxidized glutathione. NAD+ kinase was also found to be air-inactivated, the residual activity being stimulated by disulphide reductants. The most efficient of them is reduced thioredoxin from Escherichia coli which induced a five-fold increase in activity and restored 80% of the initial activity. These results which can be related to those previously observed in vivo suggest that the activity of the L. pimpinellifolium NAD+ kinase, besides its dependence on CaM, is also dependent on the reduction state of the protein which could be regulated by the thioredoxin h/NADP-thioredoxin reductase system. [ABSTRACT FROM AUTHOR]

Summary The resistance of tomato (Lycopersicon esculentum) to the pathogenic fungus Cladosporium fulvum complies with the gene-for-gene concept. Host resistance is based on specific recognition of extracellular fungal proteins, resulting in a hypersensitive response (HR). Five proteins secreted by C. fulvum were purified and the encoding cDNA clone was obtained from two novel ones among them. Various tomato breeding lines and accessions of Lycopersicon pimpinellifolium were tested for their recognitional specificity by injection of the purified proteins or potato virus X-based expression of the cDNA. We found that HR-associated recognition of one or more of these proteins, in addition to recognition of the race-specific elicitors AVR4 and AVR9 of C. fulvum, occurs among Lycopersicon species. Studies on the inheritance of this recognition confirmed that single dominant genes are involved. Furthermore, one of the extracellular proteins of C. fulvum is specifically recognized by Nicotiana paniculata, which is not a host for C. fulvum. These results indicate that plants have a highly effective surveillance system for the presence of ‘foreign’ proteins, which, together with the high mutation rate of pathogens, can explain the complex gene-for-gene relationships frequently observed in pathosystems. [ABSTRACT FROM AUTHOR]

Breeding programs in tomato for fresh consumption have concluded in very productive varieties/hybrids with an extraordinary external quality. However, internal quality has not been a priority objective in these breeding programs, so present products have a lack of important internal quality properties. Thus, internal and nutritional improvement including taste and organoleptyc characteristics are important breeding objectives at present. A screening trial to identify sources for internal quality improvement by increasing acid content was carried out. 12 accessions of Lycopersicon esculentum and 8 of L. pimpinellifolium were tested with that purpose. Content in citric, malic, oxalic and fumaric acid by HPLC, soluble solids content (SSC)(1 Brix) by refractometry and total acidity by titration with NaOH were measured. Sources for high citric, malic and fumaric acid content were found to begin those breeding programs. Results could possibly suggest an independent genetic control for every acid. [ABSTRACT FROM AUTHOR]

The genetic nature of early blight resistance in tomato was studied in three crosses at seedling and adult plant stages. A six generation mean analysis of the cross Arka Saurabh (susceptible) × IHR1939 (resistance) and its reciprocal cross revealed that the resistance to early blight was conferred by recessive polygenes at both seedling and adult plant stages. This polygenic early blight resistance revealed the importance of additive and additive × additive gene effects at seedling stage and higher magnitude of dominance and dominance× dominance gene effects at adult plant stage. Evaluation of parents, F1, F2 and backcross generations of IHR1816 (resistance) × IHR1939 (resistance) revealed that the early blight resistance genes in IHR1816 ( Lycopersicon esculentum NCEBR-1) and IHR1939 ( Lycopersicon pimpinellifolium L4394) are independent. [ABSTRACT FROM AUTHOR]

ABSTRACTNAD kinase is thought to play an important role in the plant cellular responses to biotic and abiotic stress as one of the isoforms of the enzyme is activated by the Ca2+–calmodulin (CaM) complex. NAD kinase activity was measured after short-term NaCl stress applied to isolated cells from Lycopersicon esculentum, var. Volgogradskij (NaCl-sensitive tomato) and L. pimpinellifolium, acc. PE2 (NaCl-tolerant species). NAD kinase activity remained constant in the sensitive species, whereas a sharp decrease was observed in the tolerant one. After salt treatment, an induction of the calmodulin gene(s) was observed in the two species, together with a 30–50% decrease in ‘active’ CaM content, i.e. CaM able to activate purified NAD kinase, in L. pimpinellifolium. The decrease in NAD kinase activity could not, however, be fully explained by this decrease in active CaM content. A similar decrease in NAD kinase activity was also recorded with other ionic stresses and exposure to high temperatures, but not in the case of drought, exposure to low temperatures, hormonal (indole-3-acetic acid and abscisic acid) or H2O2 treatments. External Ca2+ certainly plays a role in the biochemical mechanism(s) leading to NAD kinase inhibition, while no role could be shown for intracellular Ca2+. In addition, after salt stress, a modification of the redox state of NAD kinase seems to be responsible for the inhibition of the enzyme. [ABSTRACT FROM AUTHOR]

We have previously found an accession of Lycopersicon pimpinellifolium (Jusl.) Mill. (`TO-937') that appeared to resist attack by the two-spotted spider mite ( Tetranychus urticae Koch). L. pimpinellifolium is a very close relative of the cultivated tomato ( Lycopersicon esculentum Mill.) and thereby a potential source of desirable traits that could be introgressed to the crop species. The objective of this study was to investigate the genetics of the resistance present in `TO-937'. Resistance to infestation by the spider mite was quantified in 24-plant plots of L. pimpinellifolium accessions `TO-937' and `PE-10', L. pennellii accession `PE-45', L. esculentum cultivars `Moneymaker', `Roma' and `Kalohi' (reported to be partially resistant: Stoner & Stringfellow, 1967), and the interspecific F1 cross, L. esculentum `Moneymaker' × L. pimpinellifolium `TO-937'. Only `TO-937', the F1, and`PE-45' were found to be resistant. Resistance of `TO-937' was complete when evaluated in two small greenhouses completely planted with `TO-937' so as to simulate the genotypic homogeneity usual in commercial crops. Generations (P1, P2, F1, F2, BC1P1, and BC1P2) of a P1 (susceptible) × P2 (resistant) cross (`Moneymaker' × `TO-937') were studied for resistance in a single-plant per plot design. Resistance of `TO-937' was inherited with complete dominance and appeared to be controlled by either two or four genes according to whether segregation in the F2 or the BC1P1, respectively, were considered. However, calculation of the number of genes involved in the resistance was complicated by negative interplot interference due to the high frequency of resistant genotypes within most of the generations. [ABSTRACT FROM AUTHOR]

Most cultivars of tomato, Lycopersicon esculentum, are sensitive to low (chilling) temperatures (0–15 °C) during seed germination; however, genetic sources of cold (chilling) tolerance have been identified within the related wild species. The purpose of this study was to identify quantitative trait loci (QTLs) that contribute to cold tolerance during germination in tomato using a backcross population of an interspecific cross between a cold-sensitive tomato line (NC84173, recurrent parent) and a L. pimpinellifolium accession (LA722) that germinates rapidly under low temperatures. A total of 119 BC1 individuals were genotyped for 151 restriction fragment length polymorphism (RFLP) markers and a genetic linkage map was constructed. The parental lines and 119 BC1S1 families (self-pollinated progeny of the BC1 individuals) were evaluated for germination at a low temperature (11±0.5 °C). Germination was scored visually as radicle protrusion at 8 h intervals for 28 consecutive days. Germination response was analyzed by the survival analysis and the times to 25, 50 and 75% germination were calculated. In addition, a germination index (GI) was calculated as the weighted mean of the time from imbibition to germination for each family/line. Two QTL mapping techniques, interval mapping (using MAPMAKER/QTL) and single-point analysis (using QGENE), were used to identify QTLs. The results of both methods were similar and two chromosomal locations (3–5 putative QTLs) with significant effects on low temperature germination were identified. The L. pimpinellifolium accession had favorable QTL alleles on chromosomes 1 and NC84173 had favorable QTL alleles on chromosome 4. The percentage of phenotypic variation explained (PVE) by individual QTLs ranged from 11.9% to 33.4%. Multilocus analysis indicated that the cumulative action of all significant QTLs accounted for 43.8% of the total phenotypic variance. Digenic epistatic interactions were evident between two of the QTL-linked markers and two unlinked markers. Transgressive phenotypes were observed in the direction of cold sensitivity. The results indicate that low temperature germination of tomato seed can be improved by marker-assisted selection. [ABSTRACT FROM AUTHOR]

NaCl (140 mM) was applied to 14‐day‐old plants of salt‐sensitive Lycopersicon esculentum Mill. cv. Volgogradskij and its wild relative L. pimpinellifolium Mill. accession PE‐2. Changes in the relative growth rate of whole plant, and in the levels of inorganic and organic solutes in leaves, stems and roots were followed for 15 days after the application. Short‐term salt exposure (4–6 days of salinization) resulted in enhanced relative growth rates for L. pimpinellifolium, but did not affect growth of L. esculentum, After 6 days of salinization, the relative growth rates of both species decreased significantly; leading to practically comparable growth rates for them by day 15. In all parts of both species, the contribution of organic solutes to the osmotic potential (Ψs) gradually decreased from 30% on day 0 to a value lower than 5% on day 4. In L. pimpinellifolium, compared to L. esculentum, short‐term salt exposure resulted in (1) a higher percentage of adjustment of Ψs; and (2) increases in Na+ and K+ uptake rates, and in the levels of organic acids and proline (the level of which reached that of sugars, i.e., 10 μmol g‐1 dry weight. Conversely, in L. esculentum, drastic reductions of K+ uptake rates and organic acid levels occurred already on day 1. During long‐term salt exposure, both species were able to adjust osmotically and both exhibited decreases in organic acid levels as well as in K+ uptake and accumulation rates in all parts. The results are discussed in an attempt to explain the adaptive responses during short‐term salt exposure and the metabolic dysfunctions that lead to growth decrease after long‐term exposure to salt. [ABSTRACT FROM AUTHOR]

GA1, GA8, GA17, GA19, GA20) and GA29 were identified by combined gas chromatography-mass spectrometry (GC-MS) in immature seeds and pericarp of Lycopersicon esculentum Mill. (tomato). Higher levels of these GAs were present in the seeds than in the pericarp; seeds in addition contained GA15, GA24, GA25 and GA44. Fruits of the Lycopersicon pimpinellifolium Mill. mutant I were smaller and contained lower GA1 concentrations, but higher GA20 concentrations, than those of mutants III and IV. In contrast, differences in fruit size in L. esculentum due to position on the truss did not correlate with GA1 concentration in either the pericarp or seeds. [ABSTRACT FROM AUTHOR]

Tomato fruit growth parameters, cell number and cell size, and hormone levels [IAA, abscisic acid (ABA), zeatin (Z)/zeatin riboside (ZR), isopentenyladenosine (i-Ado)/isopentenlyadenine (i-Ade)], in the wild-type (Lycopersicon pimpinellifolium Mill.) and a semi-isogenic mutant (mutant III) differing in fruit size were investigated during fruit development. An image-processing system was used for the determination of cell number and single cell size per fruit and hormone levels were measured by radioimmuno-assay (RIA). The bigger fruits of mutant III showed higher cell numbers throughout fruit development and cells enlarged faster than in wild-type fruits. During the first 10 days of fruit growth, the main cell division period after fertilization, high concentrations of cytokinins were found, these being correlated with high cell division activity. There were only slight differences in IAA and ABA levels in the different sized fruits. The results emphasized the importance of the cell number per fruit at anthesis as a determining factor of final fruit size in tomatoes. A possible relationship between cytokinins and subsequent fruit development is discussed. [ABSTRACT FROM AUTHOR]

Cross-pollination was tested between different genotypes of Lycopersicon pimpinellifolium in an experimental plot situated in the southerly range of the species. Rates of cross-pollination were found to be highly correlated with flower size and were related to a lesser extent with degree of stigma exsertion. Comparisons of fertility suggest that exsertion of 1.5 mm or more from the anther tube orifice interferes with automatic self-pollination, thereby increasing rates of cross-pollination. A single species of Exomalopsis (Anthophoridae), observed to visit all tested genotypes of L. pimpinellifolium, was responsible for most of the pollination. Other species of solitary bees and other bee families participated in cross-pollination. [ABSTRACT FROM AUTHOR]

L. pimpinellifolium is a highly heterogeneous species, exhibiting pronounced trends from one end of its linear distribution to the other in nearly every studied genetic locus. Drastic differences between populations were also detected in genetic variability and rates of outcrossing. Highly significant positive correlations exist in every possible comparison between flower size, degree of stigma exsertion, heterozygosity, and allelic polymorphism. The hypothesis most compatible with observations proposes that the very uniform, highly self-pollinated biotypes originated from the more primitive, more variable, facultatively allogamous forms. [ABSTRACT FROM AUTHOR]

The genetic nature of bacterial wilt resistance in tomato was studied in two crosses based on the number of days of survival (quantitative) in the field before the appearance of wilt symptoms. Significant differences were observed between generation means in both crosses (LA 1421 × Cascade and LA 1421 × Caraibo). This study indicates that resistance identified in Lycopersicon esculentum var. cerasiforme LA 1421 may be different from that derived from L. pimpinellifolium. However, the genetic mechanism seems to be complex with a duplicate form of epistasis. Results suggest that selection for resistance from crosses between LA 1421 and Cascade should preferably be delayed until a high level of fixation of genes is attained. The variation observed in the F2 and BC2 progeny of the Caraibo cross, suggested that genetic combination between the two resistance sources can lead to higher levels of resistance. [ABSTRACT FROM AUTHOR]

Molecular markers were used to map and characterize quantitative trait loci (QTLs) for several characters of agronomic and biological importance in an interspecific backcross of tomato. The parents of the cross were an elite processing inbred Lycopersicon esculentum cv 'M82-1-7' and the closely related red-fruited wild species L. pimpinellifolium (LA1589). A total of 257 BC plants were grown under field conditions in Ithaca, New York and scored for 19 quantitative traits. A genetic linkage map was constructed for the same population using 115 RFLP, 3 RAPD and 2 morphological markers that spanned 1,279 cM of the tomato genome with an average interval length of 10.7 cM. A minimum of 54 putatively significant QTLs ( P<0.001; LOD> 2.4) were detected for all characters with a range of 1-7 QTLs detected per character. Of the total 54 QTLs 11% had alleles with effects opposite to those predicted by the parental phenotypes. The percentage of phenotypic variation associated with single QTLs ranged from 4% to 47%. Multilocus analysis showed that the cumulative action of all QTLs detected for each trait accounted for 12-59% of the phenotypic variation. The difference in fruit weight was controlled largely by a single major QTL ( fw2.2). Digenic epistasis was not evident. Several regions of the genome (including the region near sp on chromosome 6) showed effects on more than one trait. Implications for variety improvement and inferences about the domestication of the cultivated tomato are discussed. [ABSTRACT FROM AUTHOR]

The glasshouse whitefly, Trialeurodes vaporariorum , is an important pest of many crop plants including tomato, Solanum lycopersicum . Many wild tomato species exhibit a higher resistance to whiteflies. Therefore, locating the source of this enhanced resistance and breeding it into commercial tomato species is an important strategy to reduce the impact of pests on crops. Here, we assessed the pest resistance of Lycopersicon pimpinellifolium by comparing oviposition and feeding data from T. vaporariorum on this wild tomato species with data collected from a susceptible commercial tomato, S. lycopersicum var. 'Elegance'. The location of resistance factors was examined by use of electrical penetration graph (EPG) studies on these tomato species. Results show that whiteflies preferentially settled on the commercial tomato more often in 80 % of the replicates when given free choice between the two tomato species and laid significantly fewer eggs on L. pimpinellifolium . Whiteflies exhibited a shorter duration of the second feeding bout, reduced pathway phase probing, longer salivation in the phloem and more non-probing activities in the early stages of the EPG on the wild tomato species compared to the commercial tomato. These findings evidence that a dual mode of resistance is present in this wild tomato against T. vaporariorum : a post-penetration, pre-phloem resistance mechanism and a phloem-located factor, which to the best of our knowledge is the first time that evidence for this has been presented. These findings can be used to inform future breeding strategies to increase the resistance of commercial tomato varieties against this important pest., (© The Author(s) 2016.)