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Bacterial spot a significant disease that affects tomato crops, despite limited studies and scientific research on this disease, So This study aimed to assess the efficacy of various biological and chemical factors in controlling bacterial spot disease in the field. A field survey was conducted in Najaf Al-Ashraf, specifically in areas such as Al-Haidariya, Al-Rahima, Al-Abbasia, and 20 plastic houses. The disease incidence was observed in these locations, with infection rates from 24% to 60%. Among them, Al-Haidariya had the highest infection rate at 60%, while Al-Abbasia had the lowest at 24%. Regarding to the impact of chemical and biological inducing factors on infection severity, the treatment using nanoscale zinc oxide demonstrated superior effectiveness in reducing the severity of infection caused by Xanthomonas campestris pv. vesicatoria, In reducing the severity of the infection, which amounted to 11.6%, compared with the treatment of X.campestris 2 (control 2) only, which amounted to 74.2%.Field results also indicated that the nanoscale zinc oxide treatment was highly effective in increasing chemical indicators such as chlorophyll content, peroxidase enzyme and catalase enzyme. The values for these indicators were 12.69 mg g-1, 183.25-unit min-1 g -1 FW and 177.84-unit min-1 g -1 FW, respectively, compared to the control treatment, which recorded values of 7.79 mg g-1, 88.3-unit min-1 g -1 FW, and 74.17-unit min-1 g -1 FW, respectively. Furthermore, the treatment using Pseudomonas putida demonstrated superiority in increasing the percentage of TSS, vitamin C content, and acid percentage. The values for these parameters were 8.45%, 20.86 mg g-1, and 0.862%, respectively, compared to the control treatment, which recorded values of 4.78%, 11.09 mg g-1 and 0.462%, respectively. Moreover, the nanoscale zinc oxide treatment exhibited superior effectiveness in increasing the yield per plant, early fruit yield per plant, and total yield. The values for these parameters were 7.54 kg plant-1, 10.261 kg. plant-1 and 8.591 tons plastichouse-1 (500 m²), respectively, compared to the control treatment, which recorded values of 4.15 kg plant-1, 3.752 kg plant-1, and 4.929 tons/plastic house (500 m²), respectively. [ABSTRACT FROM AUTHOR]

Two accessions of wild species of tomato, viz. EC-520060 (Solanum habrochaites) and EC-521080 (Solanum pimpinellifolium) have been utilized for introgression of ToLCV and EB resistant gene into 12 susceptible cultivars bearing good yield traits. Most of the crosses of EC-520060 exhibited 13 (resistant): 3 (susceptible) genetic ratio but 'Flora Dade × EC-520060' expressed 3:1 genetic ratio. The crosses of EC-521080 have diverse genetic ratio of 1:2:1, 3:1 and 1:3. In result of inheritance of EB, the crosses of EC-520060 revealed 3:1 genetic ratio, and the crosses of EC-521080 represented 1:3, 1:2:1 and 3:1 genetic ratio. The crosses of EC-520060 and EC-521080 showed additive, dominance × dominance and additive × additive genetic models for both ToLCV and EB diseases. The inheritance among crosses and genetics of variables can be utilized for improvement of resistant tomato. [ABSTRACT FROM AUTHOR]

The results of the study of the effect of spraying with some agricultural chemicals on the seasonal activity of T. urticae during the season 2019-2020 showed that the lowest general average of these numbers was when treated with the growth regulator Horm on 93.33 individuals/10 leaves, which differed significantly from all other spraying treatments as well as the comparison treatment (115.12 individuals/ 10 leaves) and that the lowest general average of these numbers was on 26/10 reaching 19.80 individuals/10 leaves, and the local variety was significantly distinguished in achieving the lowest average of these numbers 104.09 individuals/10 leaves compared to the GS variety (132.47 individuals/10 leaves). The spraying treatments varied between them with regard to reducing or increasing the numbers of mites on leaves tomato is the GS variety and treatment with Horm, Fylloton and Grofalex led to a decrease in the averages of these numbers compared to the treatment of the control experiment, while the role of the rest of the treatments (Appetyzer, Acadian, Grofalex + Horm) was negative in this area, as it led to an increase in the sensitivity of these plants to infection. The GS variety was significantly superior in giving the highest content of carbohydrates, phenols and flavonoids, which amounted to 0.67 g, 12.91 mg, 4.35 mg, respectively, compared with the local variety, while the local variety was significantly superior in the leaves content of proteins only (5.12 g) compared with the GS variety. [ABSTRACT FROM AUTHOR]

The disease in tomato plants, especially on tomato leaves will have an impact on the quality and quantity of tomatoes produced. Handling disease on tomato leaves that must be done is to detect the type of disease as early as possible, then determine the treatment that must be done. Detection of its types of tomato plant diseases requires sufficient knowledge and experience. The problem is that many beginner farmers in growing tomatoes do not have much knowledge, so they have failed in growing tomatoes. Based on these cases, this study proposes a model for the early detection of disease in tomato leaves based on image processing. The research method used is divided into 5 stages, namely preprocessing, segmentation, feature extraction, classification, and performance evaluation. The feature extraction stage used is texture-based with Gabor filters and color-based filters. The final decision is determined by the Support Vector Machine (SVM) classification algorithm with the Radial Basis Function (RBF) kernel. The test results of the tomato leaf disease detection system produced an average performance parameter of 98.83% specificity, 90.37% sensitivity, 90.34% F1-score, 90.37% accuracy, and 94.60% area under the curve (AUC). Referring to the resulting of the AUC performance, the tomato leaf disease detection system is in the very good category. [ABSTRACT FROM AUTHOR]

Currently, world, horticultural producers and processors are concerned to obtain high quality organic products in conditions of economic profitability. The main aim of the research is to highlight the physico -- chemical characteristics of some improved genotypes from the species Lycopersicon esculentum Mill. obtained in ecological system in the experimental field within USAMV Iasi in 2019. Thus, the aim was to highlight some qualitative parameters, respectively: titrable acidity, pH value, total dry matter content, soluble dry matter, vitamin c, carotene and lycopene content. The biological material was represented by 37 improved tomato genotypes in order to ensure competitive horticultural techniques. The 37 genotypes of Lycopersicon esculentum Mill. showed an average value of the total dry matter content of 7.07 ± 0.5%, showing an oscillating amplitude of the lower delimited values of 4.64% (G223) and 17.9% (G265). The average pH value was 4.4 with limits that fell within the range of variation [4.15 - 4.85]. The content of vitamin C ranged between 14 mg/ 100 g and 29 mg/ 100 g. Other components with antioxidant value that have been shown in important proportions are represented by carotenes (2.36 - 21.22 mg/ 100 g) and lycopene (3.01 - 33.7 mg/ 100 g). This research results strengthens the data in the literature referring to the bioactive compounds of tomatoes emphasizing that the study was conducted for different genotypes grown in organic conditions. [ABSTRACT FROM AUTHOR]

Reactive Oxygen Species (ROS) mediated immune response in tomato (Solanum lycopersicum) plants inoculated with arbuscular mycorrhizal fungi (AMF) Glomus fasciculatum (GF) was studied in the presence of plant pathogenic fungi Fusarium oxysporum f. sp. lycopersici (FOL). Our aim was to assess how symbiosis of AMF potentiates ROS immune response system to deal pathogen mediated biotic stress. Tomato plant was inoculated with GF, FOL and GF + FOL in separate experimental sets to examine its effect on plants ROS machinery and the time taken to alleviate biotic stress. The antioxidant response was evaluated and correlated with the time provided by GF treated plants against FOL to initiate their second line of defenses as compared to only FOL treated ones. The establishment of symbiosis and development showed a positive effect on plant ROS response system and subsequently its growth. No significant difference was seen in the root mass of only GF, FOL and GF + FOL treated plants. The increase in activities of superoxide dismutase, catalase and peroxidase was similar in all the control and treated plants however; reduction in activities of these ROS scavengers was much faster in GF supplemented plants. Similar trend was also observed for ROS radicals possibly due to the involvement of antioxidant enzymes. LC-MS analysis of FOL was performed to co-relate the effect of some dominant compounds with its pathogenicity. Therefore, our results showcase AMF-GF's ability to alleviate the oxidative damage generated by biotic stress and highlights on the buffer time taken by plants defense machinery to immunize itself at various levels. [ABSTRACT FROM AUTHOR]

Summary: Tomato (Solanum lycopersicum), which is used for both processing and fresh markets, is a major crop species that is the top ranked vegetable produced over the world. Tomato is also a model species for research in genetics, fruit development and disease resistance. Genetic resources available in public repositories comprise the 12 wild related species and thousands of landraces, modern cultivars and mutants. In addition, high quality genome sequences are available for cultivated tomato and for several wild relatives, hundreds of accessions have been sequenced, and databases gathering sequence data together with genetic and phenotypic data are accessible to the tomato community. Major breeding goals are productivity, resistance to biotic and abiotic stresses, and fruit sensorial and nutritional quality. New traits, including resistance to various biotic and abiotic stresses and root architecture, are increasingly being studied. Several major mutations and quantitative trait loci (QTLs) underlying traits of interest in tomato have been uncovered to date and, thanks to new populations and advances in sequencing technologies, the pace of trait discovery has considerably accelerated. In recent years, clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene editing (GE) already proved its remarkable efficiency in tomato for engineering favorable alleles and for creating new genetic diversity by gene disruption, gene replacement, and precise base editing. Here, we provide insight into the major tomato traits and underlying causal genetic variations discovered so far and review the existing genetic resources and most recent strategies for trait discovery in tomato. Furthermore, we explore the opportunities offered by CRISPR/Cas9 and their exploitation for trait editing in tomato. Significance Statement: The pace of trait discovery in tomato has considerably accelerated in recent years thanks to advances in deep sequencing and other 'omics technologies. Here we review the genetic resources and current powerful forward genetic strategies, allowing discovery of QTLs, genes and mutations underlying remarkable traits in tomato. We also show how CRISPR/Cas9 GE now provides unprecedented opportunities for candidate gene validation, creation of new genetic diversity and breeding of improved tomato varieties. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) radiation can modulate plant defenses against herbivorous arthropods. We investigated how different UV exposure times and irradiance intensities affected tomato (Solanum lycopersicum) resistance to thrips (Frankliniella occidentalis) by assessing UV effects on thrips-associated damage and host-selection, selected metabolite and phytohormone contents, expression of defense-related genes, and trichome density and chemistry, the latter having dual roles in defense and UV protection. Short UV daily exposure times increased thrips resistance in the cultivar 'Moneymaker' but this could not be explained by changes in the contents of selected leaf polyphenols or terpenes, nor by trichome-associated defenses. UV irradiance intensity also affected resistance to thrips. Further analyses using the tomato mutants def-1, impaired in jasmonic acid (JA) biosynthesis, od-2, defective in the production of functional type-VI trichomes, and their wild-type, 'Castlemart', showed that UV enhanced thrips resistance in Moneymaker and od-2, but not in def-1 and Castlemart. UV increased salicylic acid (SA) and JA-isoleucine concentrations, and increased expression of SA- and JA-associated genes in Moneymaker, while inducing expression of JA-defensive genes in od-2. Our results demonstrate that UV-mediated enhancement of tomato resistance to thrips is probably associated with the activation of JA-associated signaling, but not with plant secondary metabolism or trichome-related traits. [ABSTRACT FROM AUTHOR]

Allelochemicals and Mi, nematode-resistant gene, are found in wild tomato species and can provide resistance to insect pests. The aim of this study was to check the resistance of tomato (Solanum lycopersicum L.) genotypes with different foliar allelochemical contents (acylsugar and/or zingiberene) associated with and not associated with the Mi gene against the whitefly (Bemisia tabaci biotype B). Fifteen tomato genotypes were tested for resistance against whitefly (Santa Clara, TOM-695, TOM-556, TOM-584, TOM-684, TOM-687, TOM-688, TOM-759, TOM-760, ZGB-703, ZGB-704, TOM-778, TOM-779, TOM-780, and PI-127826). Genotypes with high acylsugar (AS) (TOM-687 and TOM-688) as well as those with high zingiberene (ZGB) contents (ZGB-703 and ZGB-704) had lower oviposition and a lower number of nymphs when compared with genotypes with low AS and ZGB contents and without the Mi gene (Santa Clara, TOM-695, TOM-556, and TOM-584). The genotypes carrying the Mi gene, associated with low allelochemical contents, were less preferred for whitefly oviposition compared with susceptible genotypes with low AS and ZGB contents and without the Mi gene. When both the AS and ZGB allelochemicals were present in the same genotypes (TOM-778, TOM-779, and TOM-780), they showed a synergistic effect; the number of whitefly eggs and nymphs decreased in genotypes with high AS and ZGB compared with genotypes that had only one of these allelochemicals. However, the number of whitefly eggs and nymphs of genotypes with high AS and ZGB contents, individually or combined, was less than for genotypes carrying the Mi gene. These results indicate that allelochemicals are more effective than the Mi gene to provide resistance to whitefly. [ABSTRACT FROM AUTHOR]

Abstract WRKY transcription factors have been widely known to play key regulatory roles in plant disease resistance. In our previous study, characteristics of SpWRKY6 and its role in response to biotic and abiotic stress was studied. To further investigate the function of SpWRKY6 in tomato resistance to Phytophthora infestans (P. infestans), we studied the effects of loss and gain of function of SpWRKY6. Inhibition of SpWRKY6 mRNA accumulation in tomato leaves, using virus-induced gene silencing (VIGS), greatly reduced SpWRKY6 mRNA levels, and compromised tomato resistance to P. infestans. In contrast, overexpressing- SpWRKY6 tomato plants showed enhanced resistance to P. infestans, accompanied by decreased number of necrotic cells, lesion sizes and disease index. Furthermore, after P. infestans infection, the expression levels of pathogenesis related (PR) genes in transgenic tomato plants overexpressed SpWRKY6 were significantly higher than those in wild type plants, while the number of necrotic cells and the reactive oxygen species (ROS) accumulation were fewer and lower. Taken together, these results indicating that SpWRKY6 acts as a positive regulator of tomato resistance to P. infestans infection through regulating the ROS level and the expression level of PR genes along with alleviating cell membrane injury. Highlights • SpWRKY6 acts as a positive regulator of tomato resistance to P. infestans infection. • Over-expressing SpWRKY6 tomato increased resistance to P. infestans by scavenging reactive oxygen species. • SpWRKY6 -mediated tomato resistance to P. infestans through regulating the expression level of PR genes. [ABSTRACT FROM AUTHOR]

In cultivated tomato (Solanum lycopersicum), increases in photosynthetically active radiation (PAR) induce type VI leaf glandular trichomes, which are important defensive structures against arthropod herbivores. Yet, how PAR affects the type VI trichome-associated leaf chemistry and its biological significance with respect to other photomorphogenic responses in this agronomically important plant species is unknown. We used the type VI trichome-deficient tomato mutant odorless-2 (od-2) and its wild type to investigate the influence of PAR on trichome-associated chemical defenses against thrips (Frankliniella occidentalis). High PAR increased thrips resistance in wild-type plants, but not in od-2. Furthermore, under high PAR, thrips preferred od- 2 over the wild type. Both genotypes increased type VI trichome densities under high PAR. Wild-type plants, however, produced more trichome-associated allelochemicals, i.e. terpenes and phenolics, these being undetectable or barely altered in od-2. High PAR increased leaf number and thickness, and induced profound but similar metabolomic changes in wild-type and od-2 leaves. Enhanced PAR also increased levels of ABA in wild-type and od-2 plants, and of auxin in od-2, while the salicylic acid and jasmonate concentrations were unaltered. However, in both genotypes, high PAR induced the expression of jasmonic acid-responsive defense-related genes. Taken together, our results demonstrate that high PAR-mediated induction of trichome-associated chemical defenses plays a prominent role in tomato–thrips interactions. [ABSTRACT FROM AUTHOR]

The Solanaceae includes wild species that have been reported as being resistant to soil borne pathogenic agents. In the Ecuadorian Amazon region, diversity is found among specimens of this plant family. This investigation evaluated the response of seven wild Solanaceae to inoculation with root-knot nematode (Meloidogyne incognita). Resistance to the nematode was observed in the Solanaceae collected in Misahuallí (SN5) (Napo Province), which also showed a low total number of galls; whereas the other six showed susceptibility. Regarding compatibility with tree tomato (Solanum betaceum), only Solanaceae SN2 and SO7 collected in the localities of San Carlos (Orellana Province) and Curimuyo (Napo Province), respectively, resulted in less than 90% graft survival. Solanaceae S06 collected in the province of Morona Santiago, resulted in the best affinity (1.14) with the fruit species; however, SN5 also resulted in an acceptable value (1.19). SN5 would be recommended to be utilized as rootstock due to the characteristics previously mentioned. [ABSTRACT FROM AUTHOR]

Harpin Pss , an elicitor from Pseudomonas syringae pv. syringae , induces systemic acquired resistance in non-host plants, providing resistance to phytopathogens. Poor assimilation of harpin Pss is a major constraint in foliar application as biopesticide. We, therefore, prepared harpin Pss -loaded chitosan nanoparticles (H-CSNPs) to improve permeability and bio-availability of harpin Pss in tomato. H-CSNPs showed high encapsulation efficiency (90%), improved stability (p < 0.01) and bioavailability of harpin Pss (p < 0.01). Treatment with H-CSNPs resulted in sustained induction of peroxidase, phenylalanine ammonia lyase and decreased Rhizoctonia solani infection (p < 0.05). Transcripts of several genes involved in defense response were differentially expressed in harpin Pss , CSNPs and H-CSNPs treatments. While, genes involved in jasmonic acid (JA) metabolism were up-regulated during harpin Pss and H-CSNP spray treatments, indicating the role of JA pathway in triggering harpin-mediated defense responses. Furthermore, the entry of CSNPs into the cell and localization of harpin Pss into chloroplast was tracked using rhodamine-labelled CSNPs encapsulated with GFP tagged harpin Pss . The results of this study indicate use of H-CSNPs is effective for sustained-release of harpin Pss and provides resistance for prolonged duration. [ABSTRACT FROM AUTHOR]

Reductions in growth and quality due to powdery mildew (PM) disease cause significant economic losses in tomato production. Oidium neolycopersici was identified as the fungal species responsible for tomato PM disease in South Korea in the present study, based on morphological and internal transcribed spacer DNA sequence analyses of PM samples collected from two remote regions (Muju and Miryang). The genes involved in resistance to this pathogen in the tomato accession 'KNU-12' (Solanum lycopersicum var. cerasiforme) were evaluated, and the inheritance of PM resistance in 'KNU-12' was found to be conferred via simple Mendelian inheritance of a mutant allele of the PM susceptibility locus Ol-2 (SlMlo1). Full-length cDNA analysis of this newly identified mutant allele (Slmlo1.1) showed that a 1-bp deletion in its coding region led to a frameshift mutation possibly resulting in SlMlo1 loss-of-function. An alternatively spliced transcript of Slmlo1.1 was observed in the cDNA sequences of 'KNU-12', but its direct influence on PM resistance is unclear. A derived cleaved amplified polymorphic sequence (dCAPS) and a high-resolution melting (HRM) marker were developed based on the 1-bp deletion in Slmlo1.1, and could be used for efficient marker-assisted selection (MAS) using 'KNU-12' as the source for durable and broad-spectrum resistance to PM. [ABSTRACT FROM AUTHOR]

Abstract During biotic stress, plants use several mechanisms to protect themselves that include the production of reactive oxygen species (ROS), induction of pathogenesis-related proteins and cell death. Some plant growth promoting rhizobacteria (PGPR) are known to act as bio-control agents that protect crops against pathogens. The biocontrol activity of PGPR Paenibacillus lentimorbus (B-30488) against Sclerotium rolfsii showed previously where several defense-related genes were upregulated with ROS induction in tomato. We further evaluate the other possibility, i.e. role of autophagy in enhancing defense in tomato using PGPR. Confocal microscopy revealed the presence of an acidotropic dye Mono Dansyl Cadaverine (MDC) stained autophagosomes in B-30488 treated healthy and infected plants. These autophagosomes almost disappeared in plants treated with an autophagy inhibitor chloroquine. The results were also confirmed by ultrastructural analysis of leaf tissues using transmission electron microscopy. Enhanced expression of autophagy-related genes was also monitored in B-30488 primed fungal infected tissues as compared to control by qRT-PCR. Results of ROS accumulation, fluorescence, confocal and transmission electron microscopy and gene expression analysis revealed induction of autophagy using B-30488 as a biocontrol agent suggesting a role in enhancing disease resistance in tomato. Overall, the present study indicated a role of B-30488 as a biocontrol in enhancing disease resistance in tomato and also assists a better understanding of fungal pathogenesis that is expected to be useful in developing new strategies for disease control. [ABSTRACT FROM AUTHOR]

Summary: RNA sequencing (RNAseq) reads from cape gooseberry plants (Physalis peruviana) infected with Fusarium oxysporumf. sp. physali (Foph) were mapped against the lineage‐specific transcriptome of Fusarium oxysporumf. sp. lycopersici (Fol) to look for putative effector genes. Homologues of Fol SIX1(designated SIX1a and SIX1b), SIX7, SIX10, SIX12, SIX15 and Ave1were identified. The near identity of the Foph and Fol SIX7, SIX10 and SIX12genes and their intergenic regions suggest that this gene cluster may have undergone recent lateral transfer. Foph SIX1a and SIX1bwere tested for their ability to complement a SIX1 knockout mutant of Fol. This mutant shows reduced pathogenicity on susceptible tomato plants, but is able to infect otherwise resistant tomato plants carrying the I‐3 gene for Fusarium wilt resistance (SIX1 corresponds to Avr3). Neither SIX1a nor SIX1b could restore full pathogenicity on susceptible tomato plants, suggesting that any role they may play in pathogenicity is likely to be specific to cape gooseberry. SIX1b, but not SIX1a, was able to restore avirulence on tomato plants carrying I‐3.These findings separate the recognition of SIX1 from its role as an effector and suggest direct recognition by I‐3. A hypervariable region of SIX1undergoing diversifying selection within the F. oxysporum species complex is likely to play an important role in SIX1 recognition. These findings also indicate that I‐3could potentially be deployed as a transgene in cape gooseberry to protect this emerging crop from Foph.Alternatively, cape gooseberry germplasm could be explored for I‐3homologues capable of providing resistance to Foph. [ABSTRACT FROM AUTHOR]

Ralstonia spp., the causal agents of bacterial wilt, cause severe yield losses of Solanaceous crops, including tomato. The disease is difficult to control due to the pathogen's ability to survive in soil and to cause latent infections. Therefore, characterizing Ralstonia strains is important in developing effective strategies for diagnoses, quarantine and selection of biocontrol agents. In this study, 50 Ralstonia strains previously isolated from wilted tomato plants in different locations in South Africa were obtained from the culture collection of the Agricultural Research Council, Pretoria, and private seed companies. A phylogenetic analysis of the endoglucanase gene sequences revealed that 49 strains were R. pseudosolanacearum and only one was R. solanacearum. R. pseudosolanacearum strains grouped into two sequevars, 18 and 31, while the single R. solanacearum strain grouped into the cold-adapted sequevar 1, also known as race 3 biovar 2. The pathogenicity results revealed that the selected strains were pathogenic on tomato seedlings. This study thus revealed that bacterial wilt of tomato is caused primarily by R. pseudosolanacearum, but R. solanacearum IIB-1 is also present in South Africa. This information is relevant in terms of the implementation of quarantine measures, notably to put into place measures that will prevent the introduction of strain IIB-1 into other provinces of South Africa. [ABSTRACT FROM AUTHOR]

In addition to the well-known Fusarium oxysporum f.sp. lycopersici, several other Fusarium species are known to cause extensive worldwide crop losses in tomatoes. Prevalence and identities of Fusarium species infecting tomatoes in Northwest Pakistan is currently not known. In this study, we surveyed and characterized Fusarium species associated with symptomatic tomatoes in Northwest Pakistan using morphological and molecular analyses. Pathogenicity tests revealed varying degrees of virulence with some Fusarium sp. causing severe disease symptoms whereas others displaying mild symptoms. Molecular identification based on Internal Transcribed Spacer (ITS) region and TEF-1α gene sequencing classified all isolates into four major species with a majority (68.9%) belonging to Fusarium incarnatum-equiseti species complex (FIESC), followed by F. graminearum (20.7%), F. acuminatum (6.8%), and F. solani (6.8%). ISSR analyses revealed substantial genetic variability among all the Fusarium population infecting tomatoes. Genetic distance between populations from the central region and the type strain F.o. f.sp. lycopersici from Florida was the highest (0.3662), whereas between the south and central region was the lowest (0.0298), which showed that genetic exchange is negatively effected by distance. High genetic variability suggests that these Fusarium species have the potential to become a major production constraint for tomato growers. Findings in this report would greatly facilitate identification of Fusarium species in developing countries and would provide groundwork for devising and implementing disease management measures for minimizing losses caused by Fusarium species in tomatoes. [ABSTRACT FROM AUTHOR]

In a previous study, when resistant tomato plants (cv. Motelle) carrying the Sm gene were challenged with S. lycopersici , the SLNLC1 gene was significantly upregulated. In this study, to verify the function of the SLNLC1 gene response to disease resistance against S. lycopersici , virus-induced gene silencing (VIGS) was used to downregulate the expression level of the SLNLC1 gene in resistant tomato plants inoculated with S. lycopersici . After inoculation with S. lycopersici , a susceptible phenotype was observed in the silenced SLNLC1 -resistant plants. Through microscopy, impaired hypersensitive response (HR) and decreased ROS accumulation were also observed in the silenced SLNLC1 plants. In addition, the production of lignin and callose were decreased in the silenced SLNLC1 plants. Taken together, these results indicated that silencing the SLNLC1 gene attenuated the resistance of tomato plants resistant to S. lycopersici. [ABSTRACT FROM AUTHOR]

Tomato bacterial canker disease, caused by Clavibacter michiganensis subsp. michiganensis (Cmm) is a destructive disease and has been a serious concern for tomato industries worldwide. Previously, a rhizosphere isolated strain of Pseudomonas sp. 23S showed antagonistic activity toward Cmm in vitro. This Pseudomonas sp. 23S was characterized to explore the potential of this bacterium for its use in agriculture. Pseudomonas sp. 23S possesses ability to solubilize inorganic phosphorus, and to produce siderophores, indole acetic acid, and hydrogen cyanide. The strain also showed antagonistic activity against Pseudomonas syringae pv. tomato DC 3000. A plant assay indicated that Pseudomonas sp. 23S could promote growth of tomato seedlings. The potential of treating tomato plants with Pseudomonas sp. 23S to reduce the severity of tomato bacterial canker by inducing systemic resistance (ISR) was investigated using well characterized marker genes such as PR1a [salicylic acid (SA)], PI2 [jasmonic acid (JA)], and ACO [ethylene (ET)]. Two-week-old tomato plants were treated with Pseudomonas sp. 23S by soil drench, and Cmm was inoculated into the stem by needle injection on 3, 5, or 7 days post drench. The results indicated that plants treated with Pseudomonas sp. 23S, 5 days prior to Cmm inoculation significantly delayed the progression of the disease. These plants, after 3 weeks from the date of Cmm inoculation, had significantly higher dry shoot and root weight, higher levels of carbon, nitrogen, phosphorus, and potassium in the leaf tissue, and the number of Cmm population in the stem was significantly lower for the plants treated with Pseudomonas sp. 23S. From the real-time quantitative PCR (qRT-PCR) analysis, the treatment with Pseudomonas sp. 23S alone was found to trigger a significant increase in the level of PR1a transcripts in tomato plants. When the plants were treated with Pseudomonas sp. 23S and inoculated with Cmm , the level of PR1a and ACO transcripts were increased, and this response was faster and greater as compared to plants inoculated with Cmm but not treated with Pseudomonas sp. 23S. Overall, the results suggested the involvement of SA signaling pathways for ISR induced by Pseudomonas sp. 23S. [ABSTRACT FROM AUTHOR]

Biotic factors (including insect pests) constrain field-grown tomato production in Senegal. However, little information is available on the identity and life system of key pests. The objectives of this study were to: (i) update key pest records of field-grown tomato in the central vegetable-producing area along the northern coast of Senegal, known as the Niayes area; (ii) map their spatial and temporal incidence and (iii) understand insecticide use by growers to control the pests. A total of 98 tomato fields distributed in three zones along a north–south transect in the Niayes area were monitored over four crop cycles from 2012 to 2014. As expected, the tomato fruitworm Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) was the most destructive pest with an occurrence of 92% in sampled fields (90/98) and up to 38% damaged fruits in one field at the time of sampling. The proportion of damaged fruits did not differ among zones, but was significantly higher in the early dry season compared to the late dry season. The invasive tomato leafminer Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) was detected in 53% of sampled fields (52/98), mainly in the south of the Niayes area in the late dry season. Because of their ability to adapt to unstable environment and insecticides, this insect pest assemblage is a new challenge that farmers have to deal with while decreasing their use of broad-spectrum insecticides. [ABSTRACT FROM AUTHOR]

Abstract: An understanding of biocontrol activities is important when developing microorganism‐based alternatives to conventional fungicides. From our bacterial collection, we selected two strains (BBC023 and BBC047) for their outstanding antagonistic capacity against fungal phytopathogens and growth‐promoting abilities towards Arabidopsis thaliana. According to physiological and molecular characterizations, both strains were classified as Bacillus amyloliquefaciens and were tested against Botrytis cinerea in vitro and in a tomato. Both strains secrete lipopeptide‐like compounds that contribute to their in vitro antagonism. SEM‐images showed altered B. cinerea mycelial structures that were consistent with previous reports of the direct action of lipopeptides against fungal hyphae. The strains were applied to the roots (R), leaves (foliar ‐ F) or root/leaves (R/F) on tomato plants. All treatments significantly reduced the severity of B. cinerea infection (measured as a control index). However, only root applications (R and R/F) led to growth promotion in the tomato plants. We detected the production of indole acetic acid (IAA) and 2,3‐butanediol as growth promotion traits in the two strains. For both strains, the R/F treatment showed the highest control index, suggesting a synergic effect of direct antagonism against B. cinerea and resistance induction in the plant. In addition, in vitro antagonism of BBC023 and BBC047 against B. cinerea was similar; whereas in the F application, strain BBC047 significantly improved plant resistance and maintained a higher population density over time on tomato leaves, compared to BBC023. BBC047 was also able to produce a complex and robust biofilm in Msgg medium compared with that of BBC023. We linked the reduced biocontrol of BBC023 on leaves with its limited ability to generate robust biofilms and colonize the phylloplane. At last, we highlight the potential of the native Bacillus strains as promising alternatives for the development of bioproducts for sustainable agriculture. [ABSTRACT FROM AUTHOR]

We investigated the mechanisms of action of selenium nanoparticles obtained by laser ablation for their use as an abiogenic elicitor of tomato resistance to parasitic nematodes. Selenium nanoparticles induced systemic resistance of tomatoes to the root-knot nematode, stimulated plant growth and development, was involved in the PR-6 gene expression in the roots and leaves of plants subjected to invasion, and increased the activity of proteinase inhibitors (markers of systemic resistance of plants to infection). Exogenous treatment of plants with solutions of selenium nanoparticles reduced the invasion of plants by affecting the morphological and physiological parameters of the parasites in the roots. [ABSTRACT FROM AUTHOR]

Excessive use of pesticides can adversely affect the growth of non-target host plants in different ways. Pesticide-induced stress can affect non-target plants through elevated levels of reactive oxygen species (ROS) responsible for detrimental effects on cell metabolism, biochemical and other physiological activities. In response to oxidative stress, plant activates antioxidant defense system consisting of both enzymatic and non-enzymatic components. In the present investigation, three commonly used pesticides, emamectin benzoate, alpha-cypermethrin and imidacloprid, were assessed for causing oxidative stress in tomato. The oxidative damage induced by these pesticides at five different concentrations i.e. 1/4X, 1/2X, recommended application dose (X), 2X and 4X in the root and shoot tissues of tomato plant/seedlings were evaluated. Following pesticide exposure for 35 days, cell viability, cell injury, total soluble sugar (TSS) and total soluble proteins (TSP) were measured. Antioxidant activities were estimated by measuring activity levels of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) peroxidase (POD), ascorbate peroxidase (APX) and proline. Hydrogen peroxide (H2O2) levels were analysed as ROS, lipid peroxidation was measured in term of thiobarbituric acid reactive substances (TBARS) as membrane damage caused by ROS was also assessed. Analysis of the data revealed that pesticides application at higher concentrations significantly elevated ROS levels and caused membrane damage by the formation of TBARS, increased cell injury and reduced cell viability both in root and shoot tissues compared with non-treated plants. Moreover, a gradual decrease in the levels of TSS and TSP was observed in plants subjected to increasing doses of pesticides. To cope with pesticide-induced oxidative stress, a significant increase in levels of antioxidants was observed in the plants exposed to higher doses of pesticides. Shoot tissues responded more drastically by producing higher levels of antioxidants as compared to root tissues indicating the direct exposure of shoots to foliar application of pesticides. Taken together, these results strongly suggested that the application of pesticides above the recommended dose can provoke the state of oxidative stress and can cause oxidative damages in non-target host plants. [ABSTRACT FROM AUTHOR]

Early blight caused by Alternaria solani is a major production constraint in the cultivation of tomato. Success through conventional breeding has been elusive for the development of resistant varieties from wild sources due to transfer of several unacceptable quality and yield attributes from them. Therefore, transformation of tomato with gene encoding pathogen cell wall degrading enzyme chitinase isolated from Trichoderma harzianum was carried out and transgenic plants were generated. Two homozygous lines N3-5 and N8-4 with 2.5× and 4.0× higher chitinase expression, respectively, were shortlisted and were assessed at fully grown (mature) stage in net house bioassays with Alternaria solani through in vitro detached leaf as well as challenging with fungal inoculum and were compared with disease reaction at the seedling stage. Screening at the seedling stage in T2 generation in the earlier study revealed that one of the transgenic lines N3-5 exhibited moderately resistant reaction with significant reduction in lesion size as compared to the untransformed control under in vitro detached leaf bioassay and challenge inoculation assays. Screening at fully grown stage through challenge inoculation in T3 and T4 generation recorded an intermediate disease reaction (between susceptible and resistant) with significantly lower disease incidence of early blight as compared to susceptible reaction of control plants. In the in vitro detached leaf assay, these lines exhibited significantly reduced lesion size compared to control at 65 days but this difference was eliminated at 74 and 85 days signifying thereby the role of plant age. [ABSTRACT FROM AUTHOR]

Plants can produce numerous natural products, many of which have been shown to confer protection against microbial attack. In this way, we identified 1-methyltryptophan (1-MT), a natural compound produced by tomato plants in response to Pseudomonas syringae attack, whose application by soil drench provided protection against this pathogen. In the present work, we have studied the mechanisms underlying this protection. The results demonstrated that 1-MT can be considered a new activator of plant defense responses that acts by inhibiting the stomatal opening produced by coronatine (COR) and could thereby, prevent bacteria entering the mesophyll. Besides, 1-MT acts by blocking the jasmonic acid (JA) pathway that, could avoid manipulation of the salicylic acid (SA) pathway by the bacterium, and thus hinder its growth. Although the concentration of 1-MT reached in the plant did not show antimicrobial effects, we cannot rule out a role for 1-MT acting alone because it affects the expression of the fliC gene that is involved in synthesis of the flagellum. These changes would result in reduced bacterium motility and, therefore, infective capacity. The results highlight the effect of a tryptophan derivative on induced resistance in plants. [ABSTRACT FROM AUTHOR]

The objective of this study was to prove and explain the disease resistance-inducing ability of Cryptococcus laurentii on cherry tomato, as well as assay its effect on fruit quality. Apart from disease incidence, activities of defense-related enzymes and expression of critical genes were studied. With pre-treatment of C. laurentii , disease incidences of Botrytis cinerea and Alternaria alternate infected fruits were both significantly reduced. Corresponding mechanism could be explained as C. laurentii can induce resistance in cherry tomato by activating the expression of important defense-related genes, such as genes involved in salicylic acid (SA) and jasmonic acid (JA) signaling pathways and genes encoding pathogenesis related proteins, thus activating comprehensive defense reaction against pathogen invasion. Coupled with the results that fruit color was improved and other physicochemical parameters remained uninfluenced, our study suggests that pre-treatment with C. laurentii can be a promising method to preserve cherry tomato fruits. [ABSTRACT FROM AUTHOR]

Pathogenesis-related protein 5 (PR5) is encoded by the host and is related to host resistance to biological and abiotic factors. In the present study, we constructed interference expression vector pBIA-LePR5-RNAi and analyzed the resistance of transgenic tomatoes to Alternaria alternata (A. alternata). To understand the regulatory mechanism of LePR5 gene, green fluorescent protein fluorescence cellular localization and promoter functional elements were investigated. Results showed that the expression of resistance gene declined, and the morbidity of transgenic tomatoes was significantly higher than the untransformed plants. Fluorescence observation of onion epidermal cell indicated that LePR5 protein was mainly distributed in the cell membrane, apoplast, and nucleus. Furthermore, sequence analysis indicated the presence of several eukaryotic transcription factor-binding motifs, which contained TATA-box and CAAT-box; plant hormone response element, such as ABRE, TCA-element, and TGA-element; Box-W1, WUN-motif inducible transcribed by fungal elicitor and wound; and so on. [ABSTRACT FROM AUTHOR]

Certain beneficial microorganisms isolated from rhizosphere soil promote plant growth and induce resistance to a wide variety of plant pathogens. We obtained 49 fungal isolates from the rhizosphere soil of paprika plants, and selected 18 of these isolates that did not inhibit tomato seed germination for further investigation. Based on a seed germination assay, we selected four isolates for further plant tests. Treatment of seeds with isolate JF27 promoted plant growth in pot tests, and suppressed bacterial speck disease caused by Pseudomonas syringae pathovar (pv.) tomato DC3000. Furthermore, expression of the pathogenesis-related 1 (PR1) gene was higher in the leaves of tomato plants grown from seeds treated with JF27; expression remained at a consistently higher level than in the control plants for 12 h after pathogen infection. The phylogenetic analysis of a partial internal transcribed spacer sequence and the (3-tubulin gene identified isolate JF27 as Aspergillus terreus. Taken together, these results suggest that A. terreus JF27 has potential as a growth promoter and could be used to control bacterial speck disease by inducing resistance in tomato plants. [ABSTRACT FROM AUTHOR]

To investigate the responses to Botrytis cinerea (B. cinerea) infection and the effects of exogenous Ca2+ on calmodulin (CaM), phenylalanine ammonialyase (PAL), and salicylic acid (SA) biosynthesis and concentrations, we investigated the role of exogenous calcium in defense and resistance to the necrotrophic fungus B. cinerea in tomato (Lycopersicon esculentum Mill.). Specifically, 7.5 mM Ca2+ was the best treatment for plant resistance, resulting in stable and permanent resistance to the pathogen. This treatment improved plant resistance and the results also confirmed that the concentrations of CaM and SA are negatively correlated with the resistance response. [ABSTRACT FROM AUTHOR]

Programmed cell death (PCD) plays a positive role in the systemic response of plants to pathogen resistance. It has been confirmed that local tobacco mosaic virus (TMV) infecting tomato leaves can induce systemic PCD process in root-tip tissues. But up to now the underlying physiological mechanisms are poorly understood. This study focused on the detailed investigation of the physiological responses of root-tip cells during the initiation of systemic PCD. Physiological, biochemical examination and cytological observation showed that 1 day post-inoculation (dpi) of TMV inoculation there was an increase in calcium fluorescence intensity in root tip tissue cells. Then at 2 dpi, 4 dpi, 8 dpi and 15 dpi, the fluorescence intensity of calcium ion continued to increase. However, at 5 dpi, the reactive oxygen species (ROS) began to accumulate in the root-tip cells. And finally at 20 dpi, the obvious PCD reaction was detected. In addition, the experimental results also showed that the above process involved the elevation of two types of intracellular Ca 2+ , including cytoplasmic calcium ([Ca 2+ ] cyt ) and nuclear calcium ([Ca 2+ ] nuc ). The [Ca 2+ ] cyt , as a pilot signal could lead to the subsequent elevation of intracellular ROS concentration. Then, the high levels of ROS stimulated an increase of [Ca 2+ ] nuc and eventually caused PCD reactions in the root-tip tissues. In particular, the high level of nuclear calcium is an essential mediator in systemic PCD of plants. [ABSTRACT FROM AUTHOR]

The TOM1/TOM3 genes from Arabidopsis are involved in the replication of tobamoviruses. Tomato homologs of these genes, LeTH1, LeTH2 and LeTH3, are known. In this study, we examined transgenic tomato lines where inverted repeats of either LeTH1, LeTH2 or LeTH3 were introduced by Agrobacterium. Endogenous mRNA expression for each gene was detected in non-transgenic control plants, whereas a very low level of each of the three genes was found in the corresponding line. Small interfering RNA was detected in the transgenic lines. Each silenced line showed similar levels of tobamovirus resistance, indicating that each gene is similarly involved in virus replication. [ABSTRACT FROM AUTHOR]

Prevention of microbial cross-contamination during postharvest handling is an important step to minimize microbial food safety hazards of produce. Dump tanks and flume systems are widely used in many states (e.g., Florida) to transfer/wash tomatoes, and are one of the most critical points where cross-contamination may occur. This study presents data gathered over three years (2013, 2014, and 2015) on tomatoes collected from five growing regions in Florida to evaluate the risk associated with postharvest processing of tomatoes in commercial packinghouses. A total of 840 and 839 composite samples, from pre- and post-processed tomatoes, respectively, were analyzed for aerobic plate count (APC), and total coliforms (TC) and generic E. coli (EC). The least square mean (LSM) value of APC for all samples (both pre- and post-processed) was 6.0 log CFU/tomato (n = 840), whereas the LSM for TC counts was 4.1 log CFU/tomato (n = 839). Ninety-one (10.8%) and 820 (97.7%) out of 839 samples of post-processed samples had TC and generic EC counts below the detection limit of 1.3 log CFU/tomato, respectively. APC and TC counts in post-processed samples were significantly lower (p < 0.0001) than those in the pre-processed samples. There was no significant difference (p = 0.1011) in the occurrence of generic EC pre- and post-process. APC and TC were significantly higher (p < 0.0001) on samples collected in 2014 than 2013 and 2015, while the generic EC levels were not significantly different between 2013 and 2014. All samples collected in 2015 were negative for generic EC. TC counts varied significantly (p < 0.0001) by season, with highest counts in summer and lowest in the winter, over the three-year period. APC were significantly (p < 0.0001) higher in summer and fall seasons as compare to winter and spring. Microbial loads were significantly higher in the northern sites compared to the southern sites. Tomatoes from site 5 (southernmost) had significantly lower APC and TC (p < 0.0001) than recorded from other four sites. Data from this research demonstrated that the postharvest wash treatments used at the packinghouse surveyed in this study effectively reduced the overall microbial load and prevented cross-contamination. [ABSTRACT FROM AUTHOR]

Summary: In the present study, we investigated the role of Trichoderma virens (TriV_JSB100) spores or cell‐free culture filtrate in the regulation of growth and activation of the defence responses of tomato (Solanum lycopersicum) plants against Fusarium oxysporum f. sp. lycopersici by the development of a biocontrol–plant–pathogen interaction system. Two‐week‐old tomato seedlings primed with TriV_JSB100 spores cultured on barley grains (BGS) or with cell‐free culture filtrate (CF) were inoculated with Fusarium pathogen under glasshouse conditions; this resulted in significantly lower disease incidence in tomato Oogata‐Fukuju plants treated with BGS than in those treated with CF. To dissect the pathways associated with this response, jasmonic acid (JA) and salicylic acid (SA) signalling in BGS‐ and CF‐induced resistance was evaluated using JA‐ and SA‐impaired tomato lines. We observed that JA‐deficient mutant def1 plants were susceptible to Fusarium pathogen when they were treated with BGS. However, wild‐type (WT) BGS‐treated tomato plants showed a higher JA level and significantly lower disease incidence. SA‐deficient mutant NahG plants treated with CF were also found to be susceptible to Fusarium pathogen and displayed low SA levels, whereas WT CF‐treated tomato plants exhibited moderately lower disease levels and substantially higher SA levels. Expression of the JA‐responsive defensin gene PDF1 was induced in WT tomato plants treated with BGS, whereas the SA‐inducible pathogenesis‐related protein 1 acidic (PR1a) gene was up‐regulated in WT tomato plants treated with CF. These results suggest that TriV_JSB100 BGS and CF differentially induce JA and SA signalling cascades for the elicitation of Fusarium oxysporum resistance in tomato. [ABSTRACT FROM AUTHOR]

Mechanisms underlying plant non-host resistance to Xanthomonas oryzae pv. oryzicola (Xoc), the pathogen causing rice leaf streak disease, are largely unknown. Cyclic nucleotide-gated ion channels (CNGCs) are calcium-permeable channels that are involved in various biological processes including plant resistance. In this study, functions of two tomato CNGC genes SlCNGC1 and SlCNGC14 in non-host resistance to Xoc were analyzed. Silencing of SlCNGC1 and SlCNGC14 in tomato significantly enhanced Xoc-induced hypersensitive response (HR) and non-host resistance, demonstrating that both SlCNGC1 and SlCNGC14 negatively regulate non-host resistance related HR and non-host resistance to Xoc in tomato. Silencing of SlCNGC1 and SlCNGC14 strikingly increased Xoc-induced callose deposition and strongly promoted both Xoc-induced and flg22-elicited H2O2, indicating that these two SlCNGCs repress callose deposition and ROS accumulation to attenuate non-host resistance and PAMP-triggered immunity (PTI). Importantly, silencing of SlCNGC1 and SlCNGC14 apparently compromised cytosolic Ca2+ accumulation, implying that SlCNGC1 and SlCNGC14 function as Ca2+ channels and negatively regulate non-host resistance and PTI-related responses through modulating cytosolic Ca2+ accumulation. SlCNGC14 seemed to play a stronger regulatory role in the non-host resistance and PTI compared to SlCNGC1. Our results reveal the contribution of CNGCs and probably also Ca2+ signaling pathway to non-host resistance and PTI. [ABSTRACT FROM AUTHOR]

Abiotic stresses such as drought, heat or salinity are major causes of yield loss worldwide. Recent studies have revealed that the acclimation of plants to a combination of different environmental stresses is unique and therefore cannot be directly deduced from studying the response of plants to each of the different stresses applied individually. The efficient detoxification of reactive oxygen species (ROS) is thought to play a key role in enhancing the tolerance of plants to abiotic stresses. Here, we report on the role of melatonin in the protection of the photosynthetic apparatus through the increase in ROS detoxification in tomato plants grown under the combination of salinity and heat, two of the most common abiotic stresses known to act jointly. Plants treated with exogenous melatonin showed a different modulation in the expression on some antioxidant-related genes and their related enzymes. More specifically, ascorbate peroxidase, glutathione reductase, glutathione peroxidase and phospholipid hydroperoxide glutathione peroxidase (APX, GR, GPX and Ph-GPX, resepctively) showed an antagonistic regulation as compared to plants that did not receive melatonin. This translated into a better antioxidant capacity and to a lesser ROS accumulation under stress combination. The performance of the photosynthesis parameters and the photosystems was also increased in plants treated with exogenous melatonin under the combination of salinity and heat. In accordance with these findings, tomato plants treated with melatonin were found to grow better under stress combination that the non-treated ones. Our study highlights the important role that exogenous melatonin plays in the acclimation of plants to a combination of two different abiotic stresses, and how this compound can specifically regulate oxidative stress-related genes and enzymes to increase plant tolerance. [ABSTRACT FROM AUTHOR]

The article discusses the history of the greenhouse tomato industry in Ohio from 1937 to 1982. Topics discussed include the spread of the fungal disease Fusarium wilt and the Tomato and Tobacco Mosaic Viruses across the U.S., which threatened the livelihood of tomato growers; the breeding of tomatoes resistant to both diseases by Leonard Jay Alexander in 1939 and 1942, respectively; and Alexander's election to the Ohio Academy of Science and the American Phytopathological Society.

Summary: Verticillium wilts caused by soilborne fungal species of the Verticillium genus are economically important plant diseases that affect a wide range of host plants and are notoriously difficult to combat. Perception of pathogen(‐induced) ligands by plant immune receptors is a key component of plant innate immunity. In tomato, race‐specific resistance to Verticillium wilt is governed by the cell surface‐localized immune receptor Ve1 through recognition of the effector protein Ave1 that is secreted by race 1 strains of Verticillium spp. It was previously demonstrated that transgenic expression of tomato Ve1 in the model plant Arabidopsis thaliana leads to Verticillium wilt resistance. Here, we investigated whether tomato Ve1 can confer Verticillium resistance when expressed in the crop species tobacco (Nicotiana tabcum) and cotton (Gossypium hirsutum). We show that transgenic tobacco and cotton plants constitutively expressing tomato Ve1 exhibit enhanced resistance against Verticillium wilt in an Ave1‐dependent manner. Thus, we demonstrate that the functionality of tomato Ve1 in Verticillium wilt resistance through recognition of the Verticillium effector Ave1 is retained after transfer to tobacco and cotton, implying that the Ve1‐mediated immune signalling pathway is evolutionary conserved across these plant species. Moreover, our results suggest that transfer of tomato Ve1 across sexually incompatible plant species can be exploited in breeding programmes to engineer Verticillium wilt resistance. [ABSTRACT FROM AUTHOR]

With the rapid development of molecular biology technique in recent years, significant progress also has been made in genetic engineering of tomato. We reviewed the research progress in disease resistance, insect resistance, stress, quality improvement and genetic resources' utilization, respectively. The enormous application of transgenic tomato was also summarized in increasing resistance and improving quality. It was expected to provide references for the research and improvement of transgenic tomato. [ABSTRACT FROM AUTHOR]

TYLCV-IS76 is an unusual recombinant between the highly recombinogenic tomato yellow leaf curl virus (TYLCV) and tomato yellow leaf curl Sardinia virus (TYLCSV), two Mediterranean begomoviruses ( Geminiviridae ). In contrast with the previously reported TYLCV/TYLCSV recombinants, it has a TYLCSV derived fragment of only 76 nucleotides, and has replaced its parental viruses in natural conditions (Morocco, Souss region). The viral population shift coincided with the deployment of the popular Ty-1 resistant tomato cultivars, and according to experimental studies, has been driven by a strong positive selection in such resistant plants. However, although Ty-1 cultivars were extensively used in Mediterranean countries, TYLCV-IS76 was not reported outside Morocco. This, in combination with its unusual recombination pattern suggests that it was generated through a rare and possibly multistep process. The potential generation of a recombination breakpoint (RB) at locus 76 (RB76) was investigated over time in 10 Ty-1 resistant and 10 nearly isogenic susceptible tomato plants co-inoculated with TYLCV and TYLCSV clones. RB76 could not be detected in the recombinant progeny using the standard PCR/sequencing approach that was previously designed to monitor the emergence of TYLCV-IS76 in Morocco. Using a more sensitive PCR test, RB76 was detected in one resistant and five susceptible plants. The results are consistent with a very low intra-plant frequency of RB76 bearing recombinants throughout the test and support the hypothesis of a rare emergence of TYLCV-IS76. More generally, RBs were more scattered in resistant than in susceptible plants and an unusual RB at position 141 (RB141) was positively selected in the resistant cultivar; interestingly, RB141 bearing recombinants were detected in resistant tomato plants from the field. Scenarios of TYLCV-IS76 pre-emergence are proposed. [ABSTRACT FROM AUTHOR]

Key message: The negative association between the I - 3 gene and increased sensitivity to bacterial spot is due to linkage drag (not pleiotropy) and may be remedied by reducing the introgression size. Abstract: Fusarium wilt is one of the most serious diseases of tomato ( Solanum lycopersicum L.) throughout the world. There are three races of the pathogen (races 1, 2 and 3), and the deployment of three single, dominant resistance genes corresponding to each of these has been the primary means of controlling the disease. The I- 3 gene was introgressed from S. pennellii and confers resistance to race 3. Although I- 3 provides effective control, it is negatively associated with several horticultural traits, including increased sensitivity to bacterial spot disease ( Xanthomonas spp.). To test the hypothesis that this association is due to linkage with unfavorable alleles rather than to pleiotropy, we used a map-based approach to develop a collection of recombinant inbred lines varying for portions of I- 3 introgression. Progeny of recombinants were evaluated for bacterial spot severity in the field for three seasons, and disease severities were compared between I- 3 introgression haplotypes for each recombinant. Results indicated that increased sensitivity to bacterial spot is not associated with the I- 3 gene, but rather with an upstream region of the introgression. A survey of public and private inbred lines and hybrids indicates that the majority of modern I- 3 germplasm contains a similarly sized introgression for which the negative association with bacterial spot likely persists. In light of this, it is expected that the development and utilization of a reduced I- 3 introgression will significantly improve breeding efforts for resistance to Fusarium wilt race 3. [ABSTRACT FROM AUTHOR]

Whitefly the tiny homopteran is now emerging as the most destructive pest in several crops. In cotton and tomato it is now being identified as the most destructive insect causing heavy loss of yield. Field experiment was set to evaluate some biopesticides against whitefly in cotton and tomato. Among the different biopesticides evaluated Beauveria bassiana (66.11% and 63.24% reduction of population over control in cotton and tomato, respectively) and Verticillium lecanii (64.33% and 61.27% reduction of population over control in cotton and tomato, respectively) was considered as the best against whitefly, while, Metarhizium anisopliae, neemazal and karanja oil were moderately effective against whitefly population. Beauveria bassiana recorded maximum yield both in case of cotton and tomato (334.33 kg/ha and 19.5 t/ha respectively). [ABSTRACT FROM AUTHOR]

Tomato late blight caused by Phytophthora infestans (Mont.) de Bary, also known as the Irish famine pathogen, is one of the most destructive plant diseases. Wild relatives of tomato possess useful resistance genes against this disease, and could therefore be used in breeding to improve cultivated varieties. In the genome of a wild relative of tomato, Solanum habrochaites accession LA1777, we identified a new quantitative trait locus for resistance against blight caused by an aggressive Egyptian isolate of P. infestans. Using double-digest restriction site–associated DNA sequencing (ddRAD-Seq) technology, we determined 6,514 genome-wide SNP genotypes of an F2 population derived from an interspecific cross. Subsequent association analysis of genotypes and phenotypes of the mapping population revealed that a 6.8 Mb genome region on chromosome 6 was a candidate locus for disease resistance. Whole-genome resequencing analysis revealed that 298 genes in this region potentially had functional differences between the parental lines. Among of them, two genes with missense mutations, Solyc06g071810.1 and Solyc06g083640.3, were considered to be potential candidates for disease resistance. SNP and SSR markers linking to this region can be used in marker-assisted selection in future breeding programs for late blight disease, including introgression of new genetic loci from wild species. In addition, the approach developed in this study provides a model for identification of other genes for attractive agronomical traits. [ABSTRACT FROM AUTHOR]

Microbial diversity in rhizosphere soil considered as important factors for agricultural productivity. Proteomic approach in Fusarium wilt infected and healthy rhizosphere soils of tomato provided the role of microbial protein involved for the development of disease as well as resistance. In this study, two different rhizosphere soils of tomato were collected analyzed through metaproteomic approach to determine the microbial protein abundance. The result of 2D-PAGE from both the soils revealed that, totally 11 differentially proteins were expressed and they were identified through MALDI-TOF. The identified proteins were originated from bacteria, fungus and plant. The functions of proteins showed that they were involved in resistance of tomato plant. Quantification of fungal pathogen inoculums from the both soils were formed by qPCR analysis. The result of qPCR analysis in soils revealed that Fusarium wilts infected soil contained more amount of Fungal ITS, Fusarium genus and F. oxysporum inoculums than healthy soils. Hence, our result suggests that due to the activity of beneficial microbial proteins in healthy soil, protected the tomato plants from wilt disease under the field conditons. Likewise, qPCR analysis clearly demonstrated the requirement of pathogen inoculums for the development of Fusarium wilt disease in tomato. Thus, the current study concludes that exploitation of microbial protein functions unravels the role of microbes including unculturable bacteria's for the development of resistance in plants against pathogens. In the other hand, early detection of pathogen by qPCR at minimal population level helps to develop management strategies before infection. [ABSTRACT FROM AUTHOR]

The effects ofFusarium oxysporumf. sp.orthocerasas a mycoherbicide on broomrape, a weedy parasite of tomato crops, were examined during two growing seasons under field conditions. In contrast to emerged broomrapes in treated plots, none of the tomato plants inoculated with fungal pathogen showed Fusarium-wilt symptoms. In 2008, both suspension concentrations, 1 × 106and 1 × 107spore/ml, used via either root-dip or soil-inoculation three weeks after transplanting, and high-concentration-soil-inoculation one week after transplanting, reduced the number of broomrape plant and shoots per plant compared to the control. In 2009, single-point-low-dose and twice-high-dose applications of sulfosulfuron had significantly fewer broomrape plants than high-concentration-soil-inoculation three weeks after transplanting. High-concentration-root-dip inoculation decreased broomrape biomass weight significantly by 58% compared to the control in 2008. In 2009, mean biomass for single-point-application of sulfosulfuron at 50 and 75 g levels was lower than control. The highest yield was detected in high-concentration-soil-inoculation at transplanting in 2008 and in low-dose-twice-application of sulfosulfuron in 2009. Tomato yield was associated with the number of broomrape shoots per plant. There is promise that these field-scale findings will improve attempts to use mycoherbicides for biocontrol of broomrapes in tomato cropping systems. [ABSTRACT FROM AUTHOR]

In tomato, Verticillium resistance is determined by the Ve gene locus encoding two leucine-rich repeat-receptor-like proteins ( Ve1, Ve2 ). The resistance function usually is attributed to Ve1 alone, with two known alleles: Ve1 , encoding a resistance protein, and ve1 , with a premature stop codon encoding a truncated product. We have examined further Ve -gene expression in resistant and susceptible near-isolines of Verticillium -infected Craigella tomatoes, using both quantitative RT-PCR and an alternative RFLP assay. Ve1 is induced differentially in resistant and susceptible plants, while Ve2 is constitutively expressed throughout disease development. Contrary to their putative role in Verticillium resistance, these profiles were observed even with compatible Verticillium interactions, some bacterial pathogens, and transgenic tomato plants expressing the fungal Ave1 effector. This suggests broader roles in disease and/or stress. To determine the contribution of plant hormones, abscisic acid, methyl jasmonate, naphthaleneacetic acid or salicylic acid were infused independently via the tomato root and effects on Ve1 induction were confirmed using biosynthesis mutants. While all the hormones modulated Ve1 -gene induction, abscisic acid and salicylic acid were not required while jasmonic acid appears to play a more direct role. [ABSTRACT FROM AUTHOR]

The metallic complexes μ-chloro-μ-[2,5-bis (2-pyridyl)-1,3,4-thiadiazole] aqua chlorocopper (II) dichlorocopper (II) (abbreviated 2PTH-Cu 2 -Cl 4 ); aquabis [2,5-bis (2-pyridyl)-1,3,4-thiadiazole- κ 2 N 2 , N 3 ] (trifluoromethane-sulfonato- κ O) copper(II) trifluoro metrhanesulfonate (2PTH-Cu-tF) and bis[(2,5-bis(pyridine-2-yl)-1,3,4-thiadiazole-di-azido copper(II)] (2PTH-Cu-Az) were compared for their antimicrobial activities in vitro , and their aptitude to control Verticillium wilt and crown gall diseases development of tomato in the greenhouse. Results showed that the complex 2PTH-Cu-Az inhibited drastically the growth of V. dahliae in vitro. 2PTH-Cu 2 -Cl 4 and 2PTH-Cu-tF did not display any noticeable antimicrobial activity in vitro against all of the pathogens tested. However, in planta evaluation revealed that the three complexes protected tomato against crown gall similarly. They also reduced Verticillium wilt disease severity, although the complex 2PTH-Cu-Az was the most efficient. When compared to other complexes, 2PTH-Cu-Az triggered only a weak oxidative burst as revealed by H 2 O 2 measurement and the activity of ascorbate peroxidase and catalase. These results suggest that the superiority of 2PTH-Cu-Az against V. dahliae rely on its direct antifungal activity and its ability to modulate H 2 O 2 accumulation. [ABSTRACT FROM AUTHOR]

The antifungal properties and the induction of resistance by ε-poly- l -lysine (ε-PL) were examined to reveal its potential in protecting tomato plants against Botrytis cinerea . As presented herein, ε-PL at 1200 mg/L was found to have optimal in vitro antifungal activities, achieving an inhibition rate of 94.96%. In first-year field tests, ε-PL (1200 mg/L) had a control effect of up to 79.07% against tomato grey mould. Similar results were obtained in the second year. In greenhouse experiments, ε-PL was observed to effectively reduce leaf infection, with an observed control rate at 89.22%. To define the molecular-genetic mechanisms, we compared the gene expression under four different conditions: sterile water sprayed plants (Control), Botrytis -infected plants (Inf), ε-PL-treated plants (ε-PL) and ε-PL-treated + infected plants (ε-PL + Inf). Quantitative PCR analysis at 36 h after inoculation revealed that ε-PL + Inf plants exhibited significant expression and priming of several key Botrytis -induced genes in tomato. The results indicate that ε-PL promoted plant capacity of tomato to activate defense mechanisms upon pathogen attack. In total, these findings revealed that ε-PL should be an excellent biocontrol agent candidate that combined direct antifungal activity against B. cinerea and plant resistance capacity. [ABSTRACT FROM AUTHOR]

Tomato ( Solanum lycopersicum L.) ARGINASE2 (ARG2) and THREONINE DEAMINASE2 (TD2) are involved in plant defense. These enzymes act in the midgut of herbivores fed on tomato plants to degrade the essential amino acids Arg and Thr, respectively. Although it has been demonstrated that overexpression of the SlARG2 gene in tomato enhanced its resistance against M. sexta larvae, knock-down the expression of SlTD2 reduced the resistance of tomato to lepidopteran herbivores; it remains unclear whether overexpression of SlTD2 could enhance the resistance of the host plants to herbivores, or whether combined overexpression of SlARG2 and SlTD2 could lead to synergistically enhanced resistance to insects. Here, we generated transgenic Arabidopsis plants overexpressing SlARG2 ( SlARG2 OE) and SlTD2 ( SlTD2 OE) individually as well as in combination ( SlARG2-SlTD2 OE). Overexpression of these genes did not affect Arabidopsis development, seed yield, or Arg and Thr content. Insect-feeding bioassay was performed by feeding diamondback moth ( Plutella xylostella L.) larvae on detached leaves of wild-type, SlARG2 OE, SlTD2 OE, and SlARG2-SlTD2 OE plants. Larvae fed on SlARG2 OE leaves showed approximately 31% to 35% reduction in weight and 6% to 10% reduction in survival rate compared to those fed on wild-type leaves. Although larvae fed on SlTD2 OE leaves showed no reduction in survival rate, they gained less weight. Whereas larvae fed on SlARG2-SlTD2 OE leaves showed neither reduction in weight nor reduction in survival rate. We further investigated the arginase enzymatic activity of the SlARG2 OE and SlARG2-SlTD2 OE transgenic plants. The SlARG2 OE line most resistant to diamondback moth larvae displayed the highest arginase activity. Our data indicate that overexpression of SlARG2 or SlTD2 in Arabidopsis can enhance its resistance against diamondback moth, whereas combined overexpression of SlARG2 and SlTD2 did not generate synergistically increased resistance to diamondback moth. [ABSTRACT FROM AUTHOR]