Tomato Lines Research Articles

Tomato R-gene-mediated resistance against Fusarium wilt originates in roots and extends to shoots via xylem to limit pathogen colonization.

Vascular wilt disease, caused by the soil-borne fungus Fusarium oxysporum (Fo), poses a threat to many crop species. Four different tomato resistance (R) genes (I-1, I-2, I-3, and I-7) have been identified to confer protection against Fo f.sp. lycopersici (Fol). These I genes are root-expressed and mount an immune response upon perception of the invading fungus. Despite immune activation, Fol is still able to colonize the xylem vessels of resistant tomato lines. Yet, the fungus remains localized in the vessels and does not colonize adjacent tissues or cause disease. The molecular mechanism constraining Fol in the vascular system of the stem remains unclear. We here demonstrate that an I-2-resistant rootstock protects a susceptible scion from Fusarium wilt, notwithstanding fungal colonization of the susceptible scion. Proteomic analyses revealed the presence of fungal effectors in the xylem sap of infected plants, showing that the lack of fungal pathogenicity is not due to its inability to express its virulence genes. To identify mobile root-derived proteins, potentially involved in controlling fungal proliferation, comparative xylem sap proteomics was performed. We identified distinct pathogenesis-related (PR) protein profiles in xylem sap from Fol-inoculated I-1, I-2, I-3, and I-7 resistant lines. Despite structural diversity, all four immune receptors trigger the accumulation of a common set of four PR proteins: PR-5x, PR-P2, and two glucan endo-1,3-β-D-glucosidases. This research provides insights into Fusarium resistance mechanisms and identifies a core set of proteins whose abundance correlates with defense against Fusarium wilt.

Study of Tomato Source Material for Breeding Highly Productive Hybrids

In world agriculture, the tomato plays a leading role due to its high nutritional properties, high yields, adaptive abilities and a wide range of uses in fresh, culinary and processing industries. The global tomato market volume is more than 160 million tons. In the ranking of countries, Russia is in 6th place in terms of area and 11th in terms of gross production of tomatoes. Unfortunately, at the moment, a significant part of tomato seed material is imported. The implementation of the import substitution program creates the need to develop domestic breeding and seed production of this crop. The purpose of these studies was to conduct a breeding assessment of parental tomato lines for productivity traits based on statistical analysis methods and to identify promising source material for further breeding work to develop highly productive hybrids. As a result of the research, three best combinations were identified in terms of productivity of hybrids: 2f2-16(8-2) x Veneta, 108t/20 x Victor and 2f216(8-2) x Victor, which have a positive effect of specific combining ability, have average and high positive effects of the general combining ability of both maternal and paternal lines. Two maternal lines 108t/20 and 3f-14 showed a positive general combining ability for early and total productivity and its components. therefore, these parents can be successfully used in future breeding programs.

Induction of PR-Proteins and Oxidative Isozymes in Tomato Genotypes Resistant and Susceptible to Tomato Mosaic Virus and Tomato Spotted wilt Virus

Tomato spotted wilt virus (TSWV) and Tomato mosaic virus (ToMV) are two of the most common viruses that threaten tomato crops in Egypt and worldwide. The purpose of this study was to investigate the role of PRs, and oxidative isozymes in the protection of tomato plants from oxidative damage induced by viral infection in 16 tomato genotypes. A total of 16 tomato genotypes were evaluated against TSWV and ToMV separately. Changes in the content of protein and defense enzymes were studied in tomato genotypes resistant and susceptible to TSWV or ToMV. The results of the investigation showed that 16 tomato lines gave different responses to infection with TSWV or ToMV [highly resistant (HR), resistant (R), moderately resistant (MR), moderately susceptible (MS), and susceptible (S)]. In this study, the total soluble protein profiles, polyphenol oxidase (PPO), and peroxidase (POX) isozymes of the healthy tomato plants and the TSWV or ToMV infected ones were estimated by electrophoresis in Polyacrylamide gel electrophoresis (PAGE). The results showed quantitative and qualitative differences in the number of bands among the 16 tomato genotypes. Thus, the protein content and isozyme activities were increased or decreased or not changed in inoculated tomato plants with TSWV or ToMV, compared with the un-inoculated plants, depending on the genotype, virus, and degree of resistance. On the other hand, it was found a negative or low-positive correlation between disease incidence and (protein content and isozyme activities). Therefore, it is important that to understand the defense strategy of plants against viruses and how tomato plants defend themselves from virus invasion. Therefore, tomato genotypes resistant to TSWV or ToMV could be used in the tomato breeding programs to prevent viral infection

Determination of Biochemical Contents of Some Cherry and Cocktail Tomato Lines

Domates dünya genelinde en çok üretilen sebezlerden biridir ve domates ile ilgili ıslah çalışmaları da gün geçtikçe yeni bir boyut kazanmakta, yeni taleplere cevap vermektedir. Çalışmada, aynı koşullarda yetiştirilmiş kokteyl ve kiraz tipli, kırmızı, kırmızı-yeşil kırçıllı, sarı ve turuncu domateslerin mineral içeriği, C vitamini, likopen, ß-karoten miktarları, antioksidan aktiviteleri, fenolik ve flavonoid madde miktarları tespit edilmiştir. Hem insan sağlığı hemde bitkilerin gelişme ve adaptasyon yetenkleri için birçok açıdan faydalı olan bu bileşiklerden askorbik asit (4.91-60.09 mg/100 g) sarı ve turuncu domateslerde daha düşük bulunurken, koyu renkli domatesler yüksek değerler göstermiştir. Flavonoid madde miktarları 4.42-35.40 mgC/100 g arasında değişmekte olup benzer şekilde koyu renkli domateslerde daha yüksektir. Bu durum antioksidan kapasiteleri (0.28-0.71 mmolTE/100 g) içinde geçerli olup fenolik madde miktarları (30.25-80.91 mgGAE/100 g) ise boyutlara bağlı olarak kiraz domateslerde daha yüksek bulunmuştur. Likopen (0.31-18.6 mg/100 g) ve ß-karoten (0.75-6.29 mg/100 g) miktarları ise renklere bağlı olarak değişebilmekte olup sarı-turuncu domateslerin ß-karoten açısından zengin olduğu belirlenmiştir. Bu sonuçlara dayanarak albenisi yüksek bu farklı renklerdeki domateslerin tüketimi ve ıslah çalışmalarının artırılması önerilmektedir.

Characterization of tomato lines for yield components, processing traits and disease resistance based on phenotype and molecular markers

Development of improved line is one of the major activities in hybrid tomato breeding. The aim of this study was to identify improved lines based on horticultural traits, total soluble solid (TSS) and diseases resistance particularly tomato yellow leaf curl virus (ToLCV). The genotypes consisted of improved lines, jointless tomato, cherry tomato and beta carotene rich lines. These lines were evaluated in field experiment and screened against ToLCV resistance under natural field condition for two years. Molecular markers based assays were performed for resistance genes to ToLCV (Ty-2 and Ty-3), late blight (Ph-3) and root knot nematode (Mi1-2). Based on fruit yield, promising genotypes were improved lines (VRT-06, VRT-19, VRT-34 and VRT-51), jointless (EC-605037 and EC-695037), cherry tomato (VRCRT-5), and beta-carotene line (KB-20). High TSS was noticed in improved line VRT-67 (5.36 °Brix), jointless EC-695037 (5.37 °Brix) and cherry tomato VRCYT-3 (8.22 °Brix). High ToLCV resistance was recorded in improved lines (VRT-06, VRT-19, VRT-30, VRT-34, VRT-50, VRT-51, and VRT-67), jointless (EC-695037, EC-605037, EC-605094, KB-Jointless and New-Jointless), cherry tomato (VRCYT-3, VRCYT-5, VRCYT-9 and VRCYT-15), and beta carotene (KB-2, KB-3-1, KB-3-2, KB-5, KB-10, KB-14, KB-17 and KB-20). Tomato line VRT-02 having dwarf plant type was found suitable for pot culture, whereas line H-88-78-2 had very delayed and partial fruit ripening. Thus, our study identified promising lines for breeding application for economically important horticultural traits.

Employing different parameters of disease epidemics for screening and assessment of tomato genotypes against early blight disease

Early blight is the most devastating fungal disease that infects tomato (Solanum spp.) caused by Alternaria spp. Screening of a panel of fifty-one tomato lines comprising some wild relatives for resistance against early blight was carried out under uninoculated natural field conditions and under artificially controlled conditions where the latter was found to be more informative. Disease intensity was recorded at different time intervals under both conditions following Pandey’s 5-point scale to find out the percent disease intensity (PDI) and area under disease progress curve (AUDPC). Under the influence of constant inoculum load, disease intensity was found to increase with the age of plants. A positive association was shared between PDI and AUDPC while resistance was found to be negatively correlated with AUDPC. A parallelism in genotype performance was found for screening results and AUDPC under both conditions. Resistant genotypes can be utilized in future breeding schemes for producing hybrids resistant to early blight.

Development of novel specific molecular markers for the Sw-5b gene to assist with tomato spotted wilt virus-resistant tomato breeding

Tomato spotted wilt virus (TSWV) is a plant pathogen that causes devastating tomato yield losses worldwide. The Sw-5b gene is one of the most effective resistance genes for TSWV control in tomato plants, and has been widely used in resistance breeding. Molecular markers are specific DNA sequences with known locations on the chromosome; they are indispensable tools in marker-assisted selection, which detects the presence of target genes to expedite breeding. We developed gene-specific molecular markers for Sw-5b to facilitate the accurate distinction of resistance (Sw-5bR) and susceptibility (Sw-5bS) alleles of Sw-5b. Using these markers, we successfully detected Sw-5b and determined its genotype (homozygous Sw-5bR, heterozygous Sw-5bR/S, or homozygous Sw-5bS) in six tomato varieties. Then we successfully applied these markers to 46 commercial tomato cultivars to detect and determine the genotype of Sw-5b. The results revealed a striking absence of the Sw-5bR gene and high TSWV susceptibility among most of the analyzed commercial cultivars. With the assistance of the novel Sw-5b-specific molecular markers, we generated a TSWV-resistant and homozygous Sw-5bR Micro-Tom tomato line, demonstrating the practical application of these markers in plant breeding. In summary, we developed novel gene-specific molecular markers for Sw-5b, and applied them to distinguish Sw-5b alleles for TSWV resistance or susceptibility. This marker set provides a valuable tool for breeding TSWV-resistant tomato varieties.

Kiwifruit Monodehydroascorbate Reductase 3 Gene Negatively Regulates the Accumulation of Ascorbic Acid in Fruit of Transgenic Tomato Plants.

Ascorbic acid is a potent antioxidant and a crucial nutrient for plants and animals. The accumulation of ascorbic acid in plants is controlled by its biosynthesis, recycling, and degradation. Monodehydroascorbate reductase is deeply involved in the ascorbic acid cycle; however, the mechanism of monodehydroascorbate reductase genes in regulating kiwifruit ascorbic acid accumulation remains unclear. Here, we identified seven monodehydroascorbate reductase genes in the genome of kiwifruit (Actinidia eriantha) and they were designated as AeMDHAR1 to AeMDHAR7, following their genome identifiers. We found that the relative expression level of AeMDHAR3 in fruit continued to decline during development. The over-expression of kiwifruit AeMDHAR3 in tomato plants improved monodehydroascorbate reductase activity, and, unexpectedly, ascorbic acid content decreased significantly in the fruit of the transgenic tomato lines. Ascorbate peroxidase activity also increased significantly in the transgenic lines. In addition, a total of 1781 differentially expressed genes were identified via transcriptomic analysis. Three kinds of ontologies were identified, and 106 KEGG pathways were significantly enriched for these differently expressed genes. Expression verification via quantitative real-time PCR analysis confirmed the reliability of the RNA-seq data. Furthermore, APX3, belonging to the ascorbate and aldarate metabolism pathway, was identified as a key candidate gene that may be primarily responsible for the decrease in ascorbic acid concentration in transgenic tomato fruits. The present study provides novel evidence to support the feedback regulation of ascorbic acid accumulation in the fruit of kiwifruit.

Study of Variability at the Molecular Level Between Pure Lines of Cherry Tomato

Executed experience to study molecular variation and to determine the genetic fingerprint and Genetic dimension between the pure lines of a tomato Cherry are: LA3002(1),LA2838A(2),LA0797(3),LA4355(4),LA7371(5),LA3534(6),LA3535(7) and L.A. 3530(8) based on genetic indicators (ISSR and SSR) using 14 starters including 9 primers ISSR and 5 beginnings SSR and it was total package produced from these prefixes (106) package, at the rate of (7.57) packages approximately per starter, and it was the sum of the packages dissimilar in the primers shown (64) strap and represented its ratio (60,377% of the total packages that resulted at rate approximately (5) packages for the initiator. Some of the primers used showed distinct bands (visible or absent) for some pure lines that acted as genetic fingerprint for them, such as pure lines 2, 3, 6 and 8. The results showed that the highest genetic similarity among the pure lines was (0.989) between the two pure lines (4) (LA4355) and (LA7371) (5). We conclude from these results it isn’t possible to use the pointers genetics of DNA for both types (ISSR and SSR) in finding the genetic signature of pure lines of cherry tomato and its classification ame different groups and estimate the genetic distance between them for use in future education programs.

The amount and chemistry of acylsugars affects sweetpotato whitefly (Bemisia tabaci) oviposition and development, and tomato yellow leaf curl virus incidence, in field grown tomato plants.

The objectives of this study were to ascertain the impact of endogenous production of trichome-exuded acylsugars on insects and insect transmitted virus by evaluating tomato lines and their hybrids bred for acylsugar production under field settings on whiteflies and the whitefly-transmitted tomato yellow leaf curl virus. Specifically, we utilized a diverse array of tomato lines and hybrids bred for changes in acylsugar amount or type, grown in three field trials under natural whitefly and virus pressure, to investigate whether the amount of accumulated acylsugars and or the chemical profile of the acylsugars were associated with greater resistance to whiteflies and reduced incidence of tomato yellow leaf curl virus. There was considerable variation in the abundance of whitefly eggs and nymphs and incidence of tomato yellow leaf curl virus across experiments and between entries. Increasing amount of acylsugars accumulated by the tomato entries was associated with a reduction in the abundance of whitefly eggs and nymphs and a reduction in the incidence of tomato yellow leaf curl virus. Additionally, we identified lines with changes in several acylsugar fatty acids that were associated with decreased abundance of whitefly eggs and nymphs and reduced incidence of tomato yellow leaf curl virus. These results inform the utility of acylsugars as a host plant defense system for improving resistance to whiteflies and their transmitted viruses, with potential for reducing insecticides as a control method for whiteflies and provide breeding targets for optimization of existing acylsugar tomato lines to create lines with the most efficacious amount and chemistry of acylsugars.

MdNup62 involved in salt and osmotic stress tolerance in apple

Abiotic stress of plants has serious consequences on the development of the apple industry. Nuclear pore complexes (NPCs) control nucleoplasmic transport and play an important role in the regulation of plant abiotic stress response. However, the effects of NPCs on apple salt and osmotic stress responses have not been reported yet. In this study, we analyzed the expression and function of NUCLEOPORIN 62 (MdNup62), a component of apple NPC. MdNup62 expression was significantly increased by salt and mannitol (simulated osmotic stress) treatment. The MdNup62-overexpressing (OE) Arabidopsis and tomato lines exhibited significantly reduced salt stress tolerance, and MdNup62-OE Arabidopsis lines exhibited reduced osmotic stress tolerance. We further studied the function of HEAT SHOCK FACTOR A1d (MdHSFA1d), the interacting protein of MdNup62, in salt and osmotic stress tolerance. In contrast to MdNup62, MdHSFA1d-OE Arabidopsis lines showed significantly enhanced tolerance to salt and osmotic stress. Our findings suggest a possible interaction of MdNup62 with MdHSFA1d in the mediation of nuclear and cytoplasmic transport and the regulation of apple salt and osmotic stress tolerance. These results contribute to the understanding of the salt and osmotic stress response mechanism in apple.

Development of virus-induced genome editing methods in Solanaceous crops.

Genome editing (GE) using CRISPR/Cas systems has revolutionized plant mutagenesis. However, conventional transgene-mediated GE methods have limitations due to the time-consuming generation of stable transgenic lines expressing the Cas9/single guide RNA (sgRNA) module through tissue cultures. Virus-induced genome editing (VIGE) systems have been successfully employed in model plants, such as Arabidopsis thaliana and Nicotiana spp. In this study, we developed two VIGE methods for Solanaceous plants. First, we used the tobacco rattle virus (TRV) vector to deliver sgRNAs into a transgenic tomato (Solanum lycopersicum) line of cultivar Micro-Tom expressing Cas9. Second, we devised a transgene-free GE method based on a potato virus X (PVX) vector to deliver Cas9 and sgRNAs. We designed and cloned sgRNAs targeting Phytoene desaturase in the VIGE vectors and determined optimal conditions for VIGE. We evaluated VIGE efficiency through deep sequencing of the target gene after viral vector inoculation, detecting 40.3% and 36.5% mutation rates for TRV- and PVX-mediated GE, respectively. To improve editing efficiency, we applied a 37°C heat treatment, which increased the editing efficiency by 33% to 46% and 56% to 76% for TRV- and PVX-mediated VIGE, respectively. To obtain edited plants, we subjected inoculated cotyledons to tissue culture, yielding successful editing events. We also demonstrated that PVX-mediated GE can be applied to other Solanaceous crops, such as potato (Solanum tuberosum) and eggplant (Solanum melongena). These simple and highly efficient VIGE methods have great potential for generating genome-edited plants in Solanaceous crops.

Transcription factor CsMYB77 negatively regulates fruit ripening and fruit size in citrus.

MYB family transcription factors (TFs) play essential roles in various biological processes, yet their involvement in regulating fruit ripening and fruit size in citrus remains poorly understood. In this study, we have established that the R2R3-MYB TF, CsMYB77, exerts a negative regulatory influence on fruit ripening in both citrus and tomato (Solanum lycopersicum), while also playing a role in modulating fruit size in citrus. The overexpression of CsMYB77 in tomato and Hongkong kumquat (Fortunella hindsii) led to notably delayed fruit ripening phenotypes. Moreover, the fruit size of Hongkong kumquat transgenic lines was largely reduced. Based on DNA affinity purification sequencing and verified interaction assays, SEVEN IN ABSENTIA OF ARABIDOPSIS THALIANA4 (SINAT4) and PIN-FORMED PROTEIN5 (PIN5) were identified as downstream target genes of CsMYB77. CsMYB77 inhibited the expression of SINAT4 to modulate abscisic acid (ABA) signaling, which delayed fruit ripening in transgenic tomato and Hongkong kumquat lines. The expression of PIN5 was activated by CsMYB77, which promoted free indole-3-acetic acid decline and modulated auxin signaling in the fruits of transgenic Hongkong kumquat lines. Taken together, our findings revealed a fruit development and ripening regulation module (MYB77-SINAT4/PIN5-ABA/auxin) in citrus, which enriches the understanding of the molecular regulatory network underlying fruit ripening and size.

The Sw-5b NLR Immune Receptor Induces Early Transcriptional Changes in Response to Thrips and Mechanical Modes of Inoculation of Tomato spotted wilt orthotospovirus.

The NLR (nucleotide-binding leucine-rich repeat) class immune receptor Sw-5b confers resistance to Tomato spotted wilt orthotospovirus (TSWV). Although Sw-5b is known to activate immunity upon recognition of the TSWV movement protein NSm, we know very little about the downstream events that lead to resistance. Here, we investigated the Sw-5b-mediated early transcriptomic changes that occur in response to mechanical and thrips-mediated inoculation of TSWV, using near-isogenic tomato lines CNPH-LAM 147 (Sw5b+/+) and Santa Clara (Sw-5b-/-). We observed earlier Sw-5b-mediated transcriptional changes in response to thrips-mediated inoculation compared with that in response to mechanical inoculation of TSWV. With thrips-mediated inoculation, differentially expressed genes (DEGs) were observed at 12, 24, and 72 h postinoculation (hpi). Whereas with mechanical inoculation, DEGs were observed only at 72 hpi. Although some DEGs were shared between the two methods of inoculation, many DEGs were specific to either thrips-mediated or mechanical inoculation of TSWV. In response to thrips-mediated inoculation, an NLR immune receptor, cysteine-rich receptor-like kinase, G-type lectin S-receptor-like kinases, the ethylene response factor 1, and the calmodulin-binding protein 60 were induced. Fatty acid desaturase 2-9, cell death genes, DCL2b, RIPK/PBL14-like, ERF017, and WRKY75 were differentially expressed in response to mechanical inoculation. Our findings reveal Sw-5b responses specific to the method of TSWV inoculation. Although TSWV is transmitted in nature primarily by the thrips, Sw-5b responses to thrips inoculation have not been previously studied. Therefore, the DEGs we have identified in response to thrips-mediated inoculation provide a new foundation for understanding the mechanistic roles of these genes in the Sw-5b-mediated resistance. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Phytochemical Profile and Antioxidant Activity of Some Open-Field Ancient-Tomato (Solanum lycopersicum L.) Genotypes and Promising Breeding Lines

Tomato landraces have progressively faded into obscurity, making way for new hybrids and elite tomato cultivars. This study presents a comprehensive evaluation of the agronomic attributes, physicochemical properties, and functional traits across seven cultivars, comprising two high-pigment varieties, ‘HLT−F81’ and ‘HLT−F82’, as well as five underutilized ancient-tomato genotypes considered as landraces. Most of the studied genotypes exhibited satisfactory horticultural and processing traits. The average fruit weight ranged from 73.3 g in ‘Rimone’ to 91.83 g in ‘HLT−F81’, while the soluble solids content ranged from 4.66 °Brix in ‘Justar’ to 6.08 °Brix in ‘HLT−F81’. The functional quality and the content of most antioxidants, as well as the antioxidant activity in both hydrophilic and lipophilic fractions, proved to be the most discriminating parameters among the tomato genotypes. The content of β−carotene and lycopene spanned from 2.94 mg kg−1 fw in ‘Rio Grande’ to 13.94 mg kg−1 fw in ‘HLT−F82’ and 227.8 mg kg−1 fw in ‘HLT−F81’, yielding large variations compared to ‘Rio Grande’. The total phenolic content ranged from 139.83 mg GAE kg−1 fw in ‘Rimone’ to 352.41 mg GAE kg−1 fw in ‘HLT-F81’, while the flavonoid content varied from 136.16 mg RE kg−1 fw in ‘Justar’ to 311.23 mg RE kg−1 fw in ‘HLT-F82’. The presence of tocopherol isomers was genotype-dependent, with a higher content in lines carrying the high-pigment mutations. Among the tested tomato genotypes, the high-pigment tomato line ‘HLT−F81’ achieved the highest hydrophilic and lipophilic antioxidant activity values. This study primarily focused on the recovery and valorization of tomato genetic resources and landraces. It also aimed to identify desirable horticultural (yield, low-input, and low-water demand), processing (°Brix and titratable acidity), and quality (rich antioxidant berries) traits for introgression into new tomato cultivars better suited to the evolving climate conditions of the near future.

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

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

Mapping of the gene in tomato conferring resistance to root-knot nematodes at high soil temperature.

Root-knot nematodes (RKNs, Meloidogyne spp.) can cause severe yield losses in tomatoes. The Mi-1.2 gene in tomato confers resistance to the Meloidogyne species M. incognita, M. arenaria and M. javanica, which are prevalent in tomato growing areas. However, this resistance breaks down at high soil temperatures (>28°C). Therefore, it is imperative that new resistance sources are identified and incorporated into commercial breeding programmes. We identified a tomato line, MT12, that does not have Mi-1.2 but provides resistance to M. incognita at 32°C soil temperature. An F2 mapping population was generated by crossing the resistant line with a susceptible line, MT17; the segregation ratio showed that the resistance is conferred by a single dominant gene, designated RRKN1 (Resistance to Root-Knot Nematode 1). The RRKN1 gene was mapped using 111 Kompetitive Allele Specific PCR (KASP) markers and characterized. Linkage analysis showed that RRKN1 is located on chromosome 6 and flanking markers placed the locus within a 270 kb interval. These newly developed markers can help pyramiding R-genes and generating new tomato varieties resistant to RKNs at high soil temperatures.

Resistance to whitefly mediated by the Mi gene, acylsugars, and zingiberene in tomato

This study aimed to quantify and compare the effects of Mi gene, high leaf levels of acylsugars (AA), and zingiberene (ZGB) individually and in combination, regarding resistance of tomato lines to Bemisia argentifolii. The experiment included 21 genotypes selected simultaneously for high AA and ZGB content, cloned through rooting of axillary shoots with homogeneous sizes, and seven control lines produced from seeds, including 2 genotypes rich in AA (TOM-687 and TOM-688), two genotypes rich in ZGB (TOM-703 and TOM-704), and three lines with low levels of allelochemicals (cv. Santa Clara, TOM-584, and TOM-684), where the TOM-684 line carried the Mi gene. The experiment was conducted in a greenhouse using a randomized complete block design, comprising 28 treatments with 4 replications and 1 plant per plot. The AA and ZGB-rich lines showed higher resistance compared to the other control lines with low levels of allelochemicals, but the TOM-684 control line carrying the Mi gene was more resistant than the non-carriers ('Santa Clara' and TOM-584). The level of resistance conferred by ZGB was similar to that presented by AA. Both ZGB and AA provided higher levels of resistance compared to the Mi gene. The clones selected for both ZGB and AA simultaneously exhibited lower numbers of eggs and nymphs compared to the susceptible controls and were more resistant than the TOM-684 treatment. Overall, the clones even outperformed the lines rich in only one of the allelochemicals, demonstrating a synergistic effect between AA and ZGB for resistance when combined in the same tomato line.

Microtubule-associated protein SlMAP70 interacts with IQ67-domain protein SlIQD21a to regulate fruit shape in tomato.

Tomato (Solanum lycopersicum) fruit shape is related to microtubule organization and the activity of microtubule-associated proteins (MAPs). However, insights into the mechanism of fruit shape formation from a cell biology perspective remain limited. Analysis of the tissue expression profiles of different microtubule regulators revealed that functionally distinct classes of MAPs, including members of the plant-specific MICROTUBULE-ASSOCIATED PROTEIN 70 (MAP70) and IQ67 DOMAIN (IQD, also named SUN in tomato) families, are differentially expressed during fruit development. SlMAP70-1-3 and SlIQD21a are highly expressed during fruit initiation, which relates to the dramatic microtubule pattern rearrangements throughout this developmental stage of tomato fruits. Transgenic tomato lines overexpressing SlMAP70-1 or SlIQD21a produced elongated fruits with reduced cell circularity and microtubule anisotropy, while their loss-of-function mutants showed the opposite phenotype, harboring flatter fruits. Fruits were further elongated in plants coexpressing both SlMAP70-1 and SlIQD21a. We demonstrated that SlMAP70s and SlIQD21a physically interact and that the elongated fruit phenotype is likely due to microtubule stabilization induced by the SlMAP70-SlIQD21a interaction. Together, our results identify SlMAP70 proteins and SlIQD21a as important regulators of fruit elongation and demonstrate that manipulating microtubule function during early fruit development provides an effective approach to alter fruit shape.

Investigation of the influence of avermectin-containing preparations on the resistance of tomato lines to fusarium blight in vitro

Aim. Studying of the influence of avermectin-containing polyfunctional preparations Avercom and Avercom Nova on the enhancement of the resistance to fusarium wilt of tomato plants in vitro. Methods. Tomato plants were cultivated in vitro for 30 days in the presence of 25 μl/l of preparations Avercom and Avercom Nova. Analysis of the resistance of tomato plants to fusarium wilt was carried out by spraying with a conidia suspension of Fusarium oxysporum f. sp. lycopersici and F. solani. Resistance to fusarium wilt has been evaluated for 15 days after inoculation with the use of a 9-point scale. Results. It was established that cultivation in vitro of tomato plants cv. Money Maker in the presence of preparations Avercom and Avercom Nova at concentration 25 μl/l enhances the resistance of the selected plants to fusarium wilt caused by F. oxysporum f. sp. lycopersici and F. solani. In particular, resistance to these phytopathogens increased on average from 4 to 6 points on the 10th day after inoculation with F. oxysporum f. sp. lycopersici, and from 2 to 6 points on the 6th day after inoculation with F. solani. Conclusions. The results of the study show the enhancement of the resistance of tomato plants grown in the presence of Avercom and Avercom Nova preparations to the causative agents of the tomato fusarium wilt which indicates the prospects and promising opportunities of the use of microbial biopreparations for the protection of plants against biotic stress.