Wild Tomato Species Research Articles

Assessing biological factors affecting postspeciation introgression.

An increasing number of phylogenomic studies have documented a clear “footprint” of postspeciation introgression among closely related species. Nonetheless, systematic genome‐wide studies of factors that determine the likelihood of introgression remain rare. Here, we propose an a priori hypothesis‐testing framework that uses introgression statistics—including a new metric of estimated introgression, D p—to evaluate general patterns of introgression prevalence and direction across multiple closely related species. We demonstrate this approach using whole genome sequences from 32 lineages in 11 wild tomato species to assess the effect of three factors on introgression—genetic relatedness, geographical proximity, and mating system differences—based on multiple trios within the “ABBA–BABA” test. Our analyses suggest each factor affects the prevalence of introgression, although our power to detect these is limited by the number of comparisons currently available. We find that of 14 species pairs with geographically “proximate” versus “distant” population comparisons, 13 showed evidence of introgression; in 10 of these cases, this was more prevalent between geographically closer populations. We also find modest evidence that introgression declines with increasing genetic divergence between lineages, is more prevalent between lineages that share the same mating system, and—when it does occur between mating systems—tends to involve gene flow from more inbreeding to more outbreeding lineages. Although our analysis indicates that recent postspeciation introgression is frequent in this group—detected in 15 of 17 tested trios—estimated levels of genetic exchange are modest (0.2–2.5% of the genome), so the relative importance of hybridization in shaping the evolutionary trajectories of these species could be limited. Regardless, similar clade‐wide analyses of genomic introgression would be valuable for disentangling the major ecological, reproductive, and historical determinants of postspeciation gene flow, and for assessing the relative contribution of introgression as a source of genetic variation.

High-Throughput Identification of Resistance to Pseudomonas syringae pv. Tomato in Tomato using Seedling Flood Assay.

Tomato is an agronomically important crop that can be infected by Pseudomonas syringae, a Gram-negative bacterium, resulting in bacterial speck disease. The tomato-P. syringae pv. tomato pathosystem is widely used to dissect the genetic basis of plant innate responses and disease resistance. While disease was successfully managed for many decades through the introduction of the Pto/Prf gene cluster from Solanum pimpinellifolium into cultivated tomato, race 1 strains of P. syringae have evolved to overcome resistance conferred by the Pto/Prf gene cluster and occur worldwide. Wild tomato species are important reservoirs of natural diversity in pathogen recognition, because they evolved in diverse environments with different pathogen pressures. In typical screens for disease resistance in wild tomato, adult plants are used, which can limit the number of plants that can be screened due to their extended growth time and greater growth space requirements. We developed a method to screen 10-day-old tomato seedlings for resistance, which minimizes plant growth time and growth chamber space, allows a rapid turnover of plants, and allows large sample sizes to be tested. Seedling outcomes of survival or death can be treated as discrete phenotypes or on a resistance scale defined by amount of new growth in surviving seedlings after flooding. This method has been optimized to screen 10-day-old tomato seedlings for resistance to two P. syringae strains and can easily be adapted to other P. syringae strains.

Related wild species for breeding of tomato resistant to early blight disease (Alternaria solani)

Tomato (Solanum lycopersicum L.) is susceptible to many fungal diseases, including early blight of foliage caused by the necrotroph fungus Alternaria solani. Frequent application of fungicide is the major component to keep the disease low. Resistant tomato cultivar is the most desirable as it can reduce the cost of disease control significantly. So far, sources of resistance to early blight can only be found in wild relative species of tomato, and few of them have been used in traditional breeding. Unfortunately, tomato lines bred from wild donor parent still exhibit poor horticultural performances like low yield, and late maturity, and indeterminate plant habit, which hinders the release of these lines directly as cultivars. The quantitative expression and polygenic control of the early blight resistance trait, as well as the influence of plant developmental stages and environmental conditions, complicate phenotypic selection in traditional breeding. Genotypic selection by using closely linked-markers to the resistance loci is thus preferred, but mapping of early blight resistance QTL in interspecific crosses of tomato have not obtained markers which are useful for marker-assisted breeding. This review presents sources of early blight resistance in wild species of tomato and efforts in dissecting early blight resistance QTL via linkage analysis with molecular markers. Strategies to obtain closely-linked markers and genomics-assisted breeding to facilitate the introgression of useful resistance genes to cultivated tomato are discussed.

The Alcohol and Epoxy Alcohol of Zingiberene, Produced in Trichomes of Wild Tomato, Are More Repellent to Spider Mites Than Zingiberene.

Allelochemicals that are present in trichome secretions of wild tomato species play a major role in mediating interactions with arthropods, often conferring a high level of resistance via antibiosis and antixenosis. Many accessions of the wild tomato relative, Solanum habrochaites (S.h), possess high levels of resistance to arthropods. The monocyclic sesquiterpene hydrocarbon, 7-epi-zingiberene, is a major defensive component found in trichome secretions of certain accessions of S.h. We have used LA2329, an S.h. accession, as a donor in a breeding program designed to introgress zingiberene into cultivated tomato. However, the composition of trichome secretions in our population of LA2329 is segregating, with some individuals producing mainly 7-epi-zingiberene in their secretions while others producing two additional, unidentified compounds in their trichome secretions. To investigate if these other compounds may also contribute to arthropod resistance, trichome secretions were collected from plants of S.h LA2329 grown under greenhouse conditions and then major compounds were isolated by silica gel column chromatography and tested for their ability to repel two spotted-spider mite (TSSM), Tetranychus urticae. Isolation and identification of allelochemicals were aided by use of gas chromatography/mass spectroscopy. The results revealed the presence of three predominate chromatographic peaks: 7-epi-zingiberene, 9-hydroxy zingiberene, and 9-hydroxy,10,11-epoxy-zingiberene. Results of testing isolated compounds for repellency to TSSM using bridge bioassays revealed that the repellent activities of 9-hydroxy zingiberene and 9-hydroxy,10,11-epoxy-zingiberene were each significantly higher than that for 7-epi-zingiberene. These results support the idea that the degree of repellency may differ among plant allelochemicals and also emphasize the potential value of introgressing the presence of 9-hydroxy zingiberene and 9-hydroxy,10,11-epoxy-zingiberene into cultivated tomato to enhance its arthropod resistance.

Tomato yellow leaf curl virus (TYLCV)-resistant tomatoes share molecular mechanisms sustaining resistance with their wild progenitor Solanum habrochaites but not with TYLCV-susceptible tomatoes

The wild tomato species Solanum habrochaites (Sh) has been used as a source for tomato yellow leaf curl virus (TYLCV) resistance in a breeding program to generate a TYLCV-resistant tomato line. Susceptible (S) and resistant (R) lines have been developed through this program. We compared the behavior of R, S and Sh tomato plants upon infection to find out whether the resistant phenotype of R plants originated from Sh. Results showed that mechanisms involving sugar-signaling (i.e., LIN6/HT1), water channels (i.e., TIP1;1), hormone homeostasis (i.e., ABA and SA) and urea accumulation were shared by S. habrochaites and R plants, but not by S. habrochaites and S tomatoes. This finding supports the hypothesis that these mechanisms were introgressed in the R genotype from the wild tomato progenitor during breeding for TYLCV resistance. Hence, identification of genes contributing to resistance to biotic stress from wild tomato species and their introgression into domestic plants ensures tomato supply and food security.

Maintenance of root water uptake contributes to salt-tolerance of a wild tomato species under salt stress

ABSTRACT Under salt stress, the regulatory mechanism of root water uptake in tomato species with different salt-tolerance remains unclear. Here, we compared water uptake, aquaporin expression and oxidative damage in roots of wild tomato Solanum pimpinellifolium ‘L03708ʹ and cultivated tomato Solanum lycopersicum ‘M82ʹ under salt stress (150 mM NaCl) and H2O2-caused oxidative stress which is usually induced by salt stress. The results showed that the seedling growth was inhibited and root hydraulic conductance in ‘M82ʹ was decreased under salt stress, whereas these were unchanged in ‘L03708ʹ. Under salt stress, the PIP1 aquaporin abundance was decreased in ‘M82ʹ but unchanged in ‘L03708ʹ, and the PIP2 abundance was decreased in both species. The membrane damage and hydrogen peroxide accumulation were more severe in ‘M82ʹ than ‘L03708ʹ under salt stress. Exogenous H2O2 increased the membrane electrolyte leakage and decreased the root hydraulic conductance, with the changes being more profound in ‘M82ʹ than ‘L03708ʹ. The PIP1 abundance was increased in ‘L03708ʹ but decreased in ‘M82ʹ by H2O2 treatment. These results suggest that the maintenance of PIP1 abundance and antioxidant defense capability in the wild tomato species may contribute to its maintenance of root water uptake and thus salt-tolerance under salt stress.

Survey of Sensitivity to Fatty Acid-Amino Acid Conjugates in the Solanaceae.

Plants perceive insect herbivores via a sophisticated surveillance system that detects a range of alarm signals, including herbivore-associated molecular patterns (HAMPs). Fatty acid-amino acid conjugates (FACs) are HAMPs present in oral secretions (OS) of lepidopteran larvae that induce defense responses in many plant species. In contrast to eggplant (Solanum melongena), tomato (S. lycopersicum) does not respond to FACs present in OS from Manduca sexta (Lepidoptera). Since both plants are found in the same genus, we tested whether loss of sensitivity to FACs in tomato may be a domestication effect. Using highly sensitive MAP kinase (MAPK) phosphorylation assays, we demonstrate that four wild tomato species and the closely related potato (S. tuberosum) do not respond to the FACs N-linolenoyl-L-glutamine and N-linolenoyl-L-glutamic acid, excluding a domestication effect. Among other genera within the Solanaceae, we found that bell pepper (Capsicum annuum) is responsive to FACs, while there is a differential responsiveness to FACs among tobacco (Nicotiana) species, ranging from strong responsiveness in N. benthamiana to no responsiveness in N. knightiana. The Petunia lineage is one of the oldest lineages within the Solanaceae and P. hybrida was responsive to FACs. Collectively, we demonstrate that plant responsiveness to FACs does not follow simple phylogenetic relationships in the family Solanaceae. Instead, sensitivity to FACs is a dynamic ancestral trait present in monocots and eudicots that was repeatedly lost during the evolution of Solanaceae species. Although tomato is insensitive to FACs, we found that other unidentified factors in M. sexta OS induce defenses in tomato.

Characterizing Colonization Patterns of Clavibacter michiganensis During Infection of Tolerant Wild Solanum Species.

Clavibacter michiganensis is the Gram-positive causal agent of bacterial canker of tomato, an economically devastating disease with a worldwide distribution. C. michiganensis colonizes the xylem, leading to unilateral wilt, stem canker, and plant death. C. michiganensis can also infect developing tomato fruit through splash dispersal, forming exterior bird's eye lesions. There are no documented sources of qualitative resistance in Solanum spp.; however, quantitative trait loci conferring tolerance in Solanum arcanum and Solanum habrochaites have been identified. Mechanisms of tolerance and C. michiganensis colonization patterns in wild tomato species remain poorly understood. This study describes differences in symptom development and colonization patterns of the wild type (WT) and a hypervirulent bacterial expansin knockout (ΔCmEXLX2) in wild and cultivated tomato genotypes. Overall, WT and ΔCmEXLX2 cause less severe symptoms in wild tomato species and are impeded in spread and colonization of the vascular system. Laser scanning confocal microscopy and scanning electron microscopy were used to observe preferential colonization of protoxylem vessels and reduced intravascular spread in wild tomatoes. Differences in C. michiganensis in vitro growth and aggregation were determined in xylem sap, which may suggest that responses to pathogen colonization are occurring, leading to reduced colonization density in wild tomato species. Finally, wild tomato fruit was determined to be susceptible to C. michiganensis through in vivo inoculations and assessing lesion numbers and size. Fruit symptom severity was in some cases unrelated to severity of symptoms during vascular infection, suggesting different mechanisms for colonization of different tissues.

Mediterranean Long Shelf-Life Landraces: An Untapped Genetic Resource for Tomato Improvement.

The Mediterranean long shelf-life (LSL) tomatoes are a group of landraces with a fruit remaining sound up to 6–12 months after harvest. Most have been selected under semi-arid Mediterranean summer conditions with poor irrigation or rain-fed and thus, are drought tolerant. Besides the convergence in the latter traits, local selection criteria have been very variable, leading to a wide variation in fruit morphology and quality traits. The different soil characteristics and agricultural management techniques across the Mediterranean denote also a wide range of plant adaptive traits to different conditions. Despite the notorious traits for fruit quality and environment adaptation, the LSL landraces have been poorly exploited in tomato breeding programs, which rely basically on wild tomato species. In this review, we describe most of the information currently available for Mediterranean LSL landraces in order to highlight the importance of this genetic resource. We focus on the origin and diversity, the main selective traits, and the determinants of the extended fruit shelf-life and the drought tolerance. Altogether, the Mediterranean LSL landraces are a very valuable heritage to be revalued, since constitutes an alternative source to improve fruit quality and shelf-life in tomato, and to breed for more resilient cultivars under the predicted climate change conditions.

<p class="Body"><strong>Impact of leaflet trichomes on settlement and oviposition of <em>Tetranychus evansi </em>(Acari: Tetranychidae) in African and South American tomatoes</strong></p>

Red spider mite (Tetranychus evansi) is considered one of the main tomato pests in Africa. As an alternative to chemical control, the use of pest-resistant cultivars has been considered a desirable and environment-friendly choice. Therefore, our study aimed to evaluate the influence of trichomes on settlement and oviposition preferences of T. evansi in African tomato varieties, besides comparing them to South American wild tomato species. First, free- and no-choice laboratory tests were carried out to investigate settlement and oviposition preferences of females on leaflets of two South American wild tomato species (Solanum pennellii LA-716 and S. habrochaites var. hirsutum PI134417) and five African tomato varieties (S. lycopersicum cv. Kekefo, Akikon, TLCV15, Tounvi, and TOML4), the latter are widely grown in Benin. Thereafter, leaf trichome types were determined and densities were estimated and then correlated to numbers of settled females and laid eggs on leaflets of each assessed genotype. According to our findings, females strongly preferred to settle and oviposit on African varieties rather than on South American genotypes. Regarding trichome density, non-glandular type Va showed significant positive correlations with both studied parameters, with the highest amounts in African genotypes. Conversely, glandular trichome density (mainly types I, IV, and VI) presented significant negative correlations with preference indicators, with the largest densities in South American species. The high density of non-glandular trichomes on leaflets of the varieties Akikon, Tounvi, Kekefo, TOML4, and TLCV15 might have been one of the causes of preference of T. evansi females.

The de Novo Reference Genome and Transcriptome Assemblies of the Wild Tomato Species Solanum chilense Highlights Birth and Death of NLR Genes Between Tomato Species.

Wild tomato species, like Solanum chilense, are important germplasm resources for enhanced biotic and abiotic stress resistance in tomato breeding. S. chilense also serves as a model to study adaptation of plants to drought and the evolution of seed banks. The absence of a well-annotated reference genome in this compulsory outcrossing, very diverse species limits in-depth studies on the genes involved.We generated ∼134 Gb of DNA and 157 Gb of RNA sequence data for S chilense, which yielded a draft genome with an estimated length of 914 Mb, encoding 25,885 high-confidence predicted gene models, which show homology to known protein-coding genes of other tomato species. Approximately 71% of these gene models are supported by RNA-seq data derived from leaf tissue samples. Benchmarking with Universal Single-Copy Orthologs (BUSCO) analysis of predicted gene models retrieved 93.3% of BUSCO genes. To further verify the genome annotation completeness and accuracy, we manually inspected the NLR resistance gene family and assessed its assembly quality. We find subfamilies of NLRs unique to S. chilense. Synteny analysis suggests significant degree of the gene order conservation between the S. chilense, S. lycopersicum and S. pennellii genomes.We generated the first genome and transcriptome sequence assemblies for the wild tomato species Solanum chilense and demonstrated their value in comparative genomics analyses. These data are an important resource for studies on adaptation to biotic and abiotic stress in Solanaceae, on evolution of self-incompatibility and for tomato breeding.

Production and characterisation of tomato derived from interspecific hybridisation between cultivated tomato and its wild relatives

ABSTRACT Tomato (Solanum lycopersicum L.) is facing various problems of yield such as abiotic and biotic stresses. The wild tomato species are excellent source of economical traits which resistant to various types of stress and quality characters that can be transferred into cultivated tomato through intra and interspecific hybridisation. This study describes the development of inter and intraspecific hybrid tomato plants and screens the best hybrids. The interspecific hybrid tomato plants were developed by making a cross between wild tomato species and cultivated tomato. In the morphological traits, hybrids F1 showed intermediate values from both of their parents in fruit weight. Although wild parent male showed dominant impact in hybrids for many morphological characters such as leaf width and length, number of fruit set per truss, and fruit yield. The hybrids F1 also showed good characters in total soluble solids, total sugar, reducing and non-reducing sugar were enriched in cultivated tomato after crossing with wild relatives. The wild tomato has play important role in increased the lycopene level in hybrids. So, the hope that this study opens the new world gene pool for tomato breeding, ultimately contributing to the adapted of climate change and increase the tolerance to abiotic and biotic stress.

A Genotyping-by-sequencing Single Nucleotide Polymorphism–based Map and Genetic Analysis of Root Traits in an Interspecific Tomato Population

Roots impact plants’ capacity to absorb water and nutrients and thus play a vital role in tolerance to drought, salinity, and nutrient stress. In tomato (Solanum lycopersicum) breeding programs, wild tomato species have been commonly used to increase disease resistance and fruit quality and yield. However, tomato has seldom been bred for water/nutrient use efficiency or resilience to abiotic stress. Meanwhile, little knowledge of the genetic control of root traits in tomato is available. In this study, a mapping population consisting of 181 F2 progenies derived from a cross between an advanced breeding line RvT1 (S. lycopersicum) and a wild species Lche4 (Solanum cheesmaniae) was evaluated for root and shoot traits in the greenhouse. Root phenotypes were studied for the early seedling stage. Heritability estimates show that root traits are moderately or highly heritable. Root mass was highly correlated with root size (length, surface area, and volume). Shoot mass and chlorophyll content (SPAD) were moderately correlated with root mass and size. Genotyping-by-sequencing was applied to discover single nucleotide polymorphism (SNP) markers. Seven hundred and forty-two SNPs were successfully mapped, and a medium-dense linkage map was created that covered 1319.47 centimorgans (cM) with an average distance of 1.78 cM between adjacent markers. Using composite interval mapping, multiple quantitative trait loci (QTL) mapping and nonparametric mapping, 29 QTLs were identified for 12 root and shoot traits on eight chromosomes. Those QTLs of major and minor effect were involved in the differences among the F2 population. Two QTL hotspot regions associated with root mass, size, shoot mass and SPAD were identified on chromosomes 1 and 4, which was consistent with the correlation among traits. Five QTLs for shoot length and eight QTLs for SPAD were accounting for 40.01% and 55.53% of the phenotypic variation. Two QTLs were associated with 18.26% of the total variation for specific root length. The wild parent Lche4 has been characterized as a potential genetic donor of higher specific root length and might be a good parent to modify the root system of cultivated tomato.

A Transcriptional Network Promotes Anthocyanin Biosynthesis in Tomato Flesh

Dietary anthocyanins are important health-promoting antioxidants that make a major contribution to the quality of fruits. It is intriguing that most tomato cultivars do not produce anthocyanins in fruit. However, the purple tomato variety Indigo Rose, which has the dominant Aft locus combined with the recessive atv locus from wild tomato species, exhibits light-dependent anthocyanin accumulation in the fruit skin. Here, we report that Aft encodes a functional anthocyanin activator named SlAN2-like, while atv encodes a nonfunctional version of the anthocyanin repressor SlMYBATV. The expression of SlAN2-like is responsive to light, and the functional SlAN2-like can activate the expression of both anthocyanin biosynthetic genes and their regulatory genes, suggesting that SlAN2-like acts as a master regulator in the activation of anthocyanin biosynthesis. We further showed that cultivated tomatoes contain nonfunctional alleles of SlAN2-like and therefore fail to produce anthocyanins. Consistently, expression of a functional SlAN2-like gene driven by the fruit-specific promoter in a tomato cultivar led to the activation of the entire anthocyanin biosynthesis pathway and high-level accumulation of anthocyanins in both the peel and flesh. Taken together, our study exemplifies that efficient engineering of complex metabolic pathways could be achieved through tissue-specific expression of master transcriptional regulators.

Alternative Splicing in the Anthocyanin Fruit Gene Encoding an R2R3 MYB Transcription Factor Affects Anthocyanin Biosynthesis in Tomato Fruits

Tomato (Solanum lycopersicum) fruits are typically red at ripening, with high levels of carotenoids and a low content in flavonoids. Considerable work has been done to enrich the spectrum of their health-beneficial phytochemicals, and interspecific crosses with wild species have successfully led to purple anthocyanin-colored fruits. The Aft (Anthocyanin fruit) tomato accession inherited from Solanum chilense the ability to accumulate anthocyanins in fruit peel through the introgression of loci controlling anthocyanin pigmentation, including four R2R3 MYB transcription factor-encoding genes. Here, we carried out a comparative functional analysis of these transcription factors in wild-type and Aft plants, and tested their ability to take part in the transcriptional complexes that regulate the biosynthetic pathway and their efficiency in inducing anthocyanin pigmentation. Significant differences emerged for SlAN2like, both in the expression level and protein functionality, with splicing mutations determining a complete loss of function of the wild-type protein. This transcription factor thus appears to play a key role in the anthocyanin fruit pigmentation. Our data provide new clues to the long-awaited genetic basis of the Aft phenotype and contribute to understand why domesticated tomato fruits display a homogeneous red coloration without the typical purple streaks observed in wild tomato species.

Differences in the sucrose synthase gene SUS1 expression pattern between Solanum lycopersicum and wild tomato species

Plant sucrose synthase (SUS) reversibly hydrolyzes sucrose, incorporating sucrose into different metabolic pathways. SUS1 homologous genes were characterized in 12 accessions of cultivated tomato Solanum lycopersicum and wild tomato species (Solanum section Lycopersicon). In total, 34 non-synonymous SNPs were found; among them, 17 caused radical amino acid substitutions, mostly in the wild species. The SUS1-based phylogenetic tree topology was represented by two clusters of red-fruited and green-fruited species, where S. pennellii and S. habrochaites showed the highest divergence. SUS1 transcription was detected in source and sink organs of one cultivated and four wild tomato species; it was the highest in buds and flowers, but lower in mature green fruit of the final size. In leaves and roots, the level of SUS1 expression corresponded to species evolutionary history, whereas no correlation was found between SUS1 levels and fruit size and sugar composition. Our findings suggest that SUS1-mediated reversible sucrose hydrolysis is important for maintaining the balance between sucrose and its monomers not only in fruits, but also in the other tomato organs.

Bactericera cockerelli resistance in the wild tomato Solanum habrochaites is polygenic and influenced by the presence of Candidatus Liberibacter solanacearum

The tomato-potato psyllid (TPP), Bactericera cockerelli, is a vector for the phloem-limited bacterium Candidatus Liberibacter solanacearum (Lso), the causative agent of economically important diseases including tomato vein-greening and potato zebra chip. Here, we screened 11 wild tomato relatives for TPP resistance as potential resources for tomato (Solanum lycopersicum) cultivar development. Six accessions with strong TPP resistance (survival <10%) were identified within S. habrochaites, S. pennelli, S. huaylasense, S. chmielewskii, S. corneliomulleri, and S. galapagense. Two S. pennelli and S. corneliomulleri accessions also showed resistance to Lso. We evaluated recombinant inbred lines (RILs) carrying resistance from S. habrochaites accession LA1777 in the S. lycopersicum background and identified major quantitative trait loci (QTLs) responsible for adult TPP mortality and fecundity in several RILs carrying insertions in different chromosomes, indicating the polygenic nature of these traits. Analysis of a major resistance QTL in RIL LA3952 on chromosome 8 revealed that the presence of Lso is required to increase adult TPP mortality. By contrast, the reduced TPP oviposition trait in LA3952 is independent of Lso. Therefore, resistance traits are available in wild-tomato species, although their complex inheritance and modes of action require further characterisation to optimise their utilisation for tomato improvement.

High-Altitude Wild Species Solanum arcanum LA385-A Potential Source for Improvement of Plant Growth and Photosynthetic Performance at Suboptimal Temperatures.

Plant growth, development, and yield of current tomato cultivars are directly affected by low temperatures. Although wild tomato species have been suggested as a potential source for low temperature tolerance, very little is known about their behavior during the reproductive phase. Here, we investigated the impact of suboptimal temperatures (SOT, 16/14°C), as compared to control temperatures (CT, 22/20°C), on plant growth, photosynthetic capacity, and carbohydrate metabolism. Under these conditions, two genotypes were analyzed: a Solanum lycopersicum cultivar Moneymaker and a high-altitude wild species Solanum arcanum LA385, from flowering onset until a later stage of fruit development. Total dry matter production in cv. Moneymaker was reduced up to 30% at SOT, whereas it was hardly affected in wild accession LA385. Specific leaf area, total leaf area, and number of fruits were also decreased at SOT in cv. Moneymaker. In contrast, wild accession LA385 showed an acclimation to SOT, in which ΦPSII and net CO2 assimilation rates were less affected; a similar specific leaf area; higher total leaf area; and higher number of fruits compared to those at CT. In addition, LA385 appeared to have a more distinct sucrose metabolism than cv. Moneymaker at both temperatures, in which it had higher contents of sucrose-6-phosphate, sucrose, and ratio of sucrose: starch in leaves and higher ratio of sucrose: hexose in fruits. Overall, our findings indicate that wild accession LA385 is able to acclimate well to SOT during the reproductive phase, whereas growth and development of cv. Moneymaker is reduced at SOT.

Biomass association in specimens and interspecific hybrids of tomatoes

The objective of this study is to analyze the growth of wild species of tomato, of the cultivar Redenção and of the respective F1 hybrids of interspecific crossings. We evaluated six wild-type accessions (Solanum pimpinellifolium ‘AF 26970’, S. galapagense ‘LA-1401’, S. peruvianum ‘AF 19684’, S. habrochaites var. hirsutum ‘PI-127826’, S. habrochaites var. glabratum ‘PI-134417’, and S. pennellii ‘LA-716’) and the commercial cultivar Redenção (S. lycopersicum) together with their respective interspecific hybrids. In completely randomized blocks and plots subdivided by time (16, 28, 42, 56, 70, and 84 days after transplanting), we evaluated leaf area (LA), total dry matter (TDM), absolute growth rate (AGR), relative growth rate (RGR) and net assimilation rate (NAR). The distribution of assimilates in the different organs followed different patterns according to genotype. There was a greater accumulation of LA and TDM in the accessions ‘PI-127826’ and ‘PI-134417’ and in the hybrids ‘Redenção’ x ‘PI-127826’ and ‘Redenção’ x ‘PI-134417’. Due to a heterotrophic effect provided by the crossings, there were higher LA, TDM, AGR, RGR and NAR in hybrids than in parent plants. The accessions ‘PI-127826’ and ‘PI-134417’ presented a potential to be donor parents for obtaining tomatoes with a greater capacity of net assimilation and biomass accumulation.

Nutraceutical Characterization of Anthocyanin-Rich Fruits Produced by "Sun Black" Tomato Line.

Tomato (Solanum lycopersicum L.) is one of the most cultivated vegetable in the world and it represents a large source of bioactive compounds, including carotenoids and polyphenols (phenolic acids and flavonoids). However, the concentration of flavonoids in tomato is considered sub-optimal, particularly because anthocyanins are not generally present. Therefore, this crop has been the object of an intense metabolic engineering in order to obtain anthocyanin-enriched tomatoes by using either breeding or transgenic strategies. Some wild tomato species, such as S. chilense and S. cheesmaniae, biosynthesize anthocyanins in the fruit sub-epidermal tissue, and some alleles from those genotypes have been introgressed into a new developed purple tomato line, called “Sun Black” (SB). It is a tomato line with a purple skin color, both in green and in red fruit stages, due to the biosynthesis of anthocyanins in the peel, and a normal red color pulp, with a taste just like a traditional tomato. SB is the result of a breeding programme and it is not a genetically modified (GM) product. We report the chemical characterization and structure elucidation of the attractive anthocyanins found in the peel of SB tomato, as well as other bioactive compounds (carotenoids, polyphenols, vitamin C) of the whole fruit. Using one- and two-dimensional NMR experiments, the two main anthocyanins were identified to be petunidin 3-O-[6″-O-(4‴-O-E-p-coumaroyl-α-rhamnopyranosyl) -β-glucopyranoside]-5-O-β-glucopyranoside (petanin) and malvidin 3-O-[6″-O-(4‴-O-E-p-coumaroyl-α-rhamnopyranosyl)-β-glucopyranoside]-5-O-β-glucopyranoside (negretein). The total anthocyanins in the whole ripe fruit was 1.2 mg/g dry weight (DW); 7.1 mg/100 g fresh weight (FW). Chlorogenic acid (the most abundant phenolic acid) was 0.6 mg/g DW; 3.7 mg/100 g FW. The main flavonol, rutin was 0.8 mg/g DW; 5 mg/100 g FW. The total carotenoid content was 211.3 μg/g DW; 1,268 μg/100 g FW. The total phenolic content was 8.6 mg/g DW; 52.2 mg/100 g FW. The vitamin C content was 37.3 mg/100 g FW. The antioxidant activities as measured by the TEAC and ORAC assays were 31.6 and 140.3 μmol TE/g DW, respectively (193 and 855.8 μmol TE/100 g FW, respectively). The results show the unique features of this new tomato genotype with nutraceutical properties.