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A linkage map of the 12 tomato chromosomes constructed based on a BC
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Late blight (LB), caused by the oomycete Phytophthora infestans,
and early blight (EB), caused by the fungi Alternaria solani
and A. tomatophila, are two common and destructive foliar diseases
of the cultivated tomato (Solanum lycopersicum) and potato
(Solanum tuberosum) in the United States and elsewhere in the
world. While LB can infect and devas...
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Citations
... Furthermore, beneficial microbes may stimulate chlorophyll synthesis by increasing the production of pyridoxal enzymes, which are essential in the production of α-amino levulinic synthetase, a primary compound in chlorophyll synthesis (Ramadan et al., 2003). Additionally, early blight damages the inner and outer membranes of the infected plants by destroying the structure and operation of mitochondria before chloroplasts (Foolad et al., 2008). Similarly, the reduction in chlorophyll content is mainly due to the intensification of early blight infection and defoliation due to this disease (Zhao et al., 2013). ...
... In Algeria, three major clonal lineages of P. infestans (EU_13_A2, EU_2_A1 and EU_23_A1) have been identified in commercial potato and tomato production regions [5]. However, most methods of controlling this pathogen are based on the application of expensive fungicides, which can be less effective when weather conditions are favorable for pathogen spread [6] or the emergence of new P. infestans genotypes resistant to fongicides. ...
... При высокой степени устойчивости возбудителей фитофтороза к фунгицидам эффективность обработок низка, а передозировка препарата угрожает здоровью потребителей плодов томата. Возможность противостоять фитофторозу заключается в выращивании устойчивых сортов [7,8,21]. ...
... В качестве генетических ресурсов устойчивости растений томата к фитофторозу были определены в основном дикие виды, в частности красноплодный вид S. pimpinellifolium и зеленоплодный S. habrochaites [21,29]. ...
... Ген Рh-3 обеспечивает сопротивление против широкого спектра изолятов фитофторы, является самым эффективным фактором устойчивости к фитофторозу томата [30][31][32]. Во многих странах мира разрабатываются селекционные программы, ориентированные на включение в геном получаемых форм томата гена Ph-3 [21,30,[33][34][35][36]. В связи с тем, что наличие гена Ph-3 позволяет достигнуть высокого уровня сопротивления болезни, он был включен во многие селекционные линии томата [19,21,30], но его долговечность не проверялась [29]. ...
This review presents an analysis of the literature, which indicates the popularity of breeding methods in the fight against oomycete and fungal diseases of tomato: late blight (pathogen − Phytophthora infestans (Mont.) de Bary), fusarium wilt (pathogen − Fusarium oxysporum f. sp. lycopersici (Sacc.) Snyder and Hansen), early blight or alternariosis (pathogens − representatives of the genus Alternaria), cladosporiosis (pathogen−Cladosporium fulvum Cook.). Theoretical and practical achievements, the latest developments in genetics, molecular biology, plant physiology, microbiology are considered. Special attention is paid to modern information about the diversity of tomato pathogens, their morphological, genetic, physiological features, including racial composition; the presence of pathogen resistance genes in the gene pool of the culture under study, their mapping and the possibility of introduction into the genome from other sources; about the developed markers of target genes and loci of quantitative traits; the degree of associations between a molecular marker and a target gene; about the features of inheritance of the studied trait, as well as the possibility of pyramiding R-genes and QTL in one genotype. To accelerate and improve the efficiency of tomato breeding for resistance to pathogens, these issues are of great importance. Their study will strengthen the integration of modern biotechnology with the traditional breeding process, which is carried out by classical methods.
... This, in turn, results in diminished fruit quality and substantial yield loss. Collar rot, on the other hand, is characterized by initial dark and sunken lesions on the stem, which later expand to form lensshaped lesions with concentric rings resembling those found on leaves. In young seedlings, lesions at ground level encircle the stem, damaging the vascular system and creating "collars" [14] . Infections on fruit cause dark, sunken, leathery, and purple lesions at the stem-end. ...
... EB can be managed through various approaches, viz., fungicidal treatments, cultural management, use of resistant plant varieties, etc. Among these, cultural practices and fungicidal treatment are the most commonly employed methods [14] . Cultural practices encompass various strategies, including maintaining a healthy field and crop vigor, implementing good sanitation measures, removing infected plant debris and volunteer weeds from the vicinity of the field, practicing crop rotation, incorporating organic inputs like biochar, and reducing leaf wetness through soil-directed irrigation systems [15] . ...
... Residual synthetic chemicals can also result in the accumulation of heavy metals in the soil, which can be toxic to plants as well as soil microorganisms and fauna [25] . Fungicides can face limitations in high disease pressure, and such treatments may not be economically viable or environmentally sustainable [14] . For instance, a study conducted in North Carolina found that a total of 15 fungicide applications were necessary per growing season to effectively manage diseases of fungal origin [32] . ...
Tomato is one of the major solanaceous vegetables, which has a unique place in the global vegetable market. Instead of being a high-value crop, there is still a need to do improvement in its potential against various biotic and abiotic stressors that adequately demolish its real yield. Alternaria solani (causing early blight disease) is designated as one of the fatal organisms that may reduce tomato crop yield by up to 80%. There were lots of methods, viz., chemical, cultural and biological suggested to overcome it. However, chemical strategies are much in vogue, but they have several negative consequences for human health and the ecosystem. Enlightening this issue, the efficacy of various treatments, viz., chemical fungicides (Amistar Top ® , Nativo ® , and Contaf ®), biochar and fungal bioagent (Trichoderma viride) was assessed under both in vivo and in vitro conditions. Induced resistance is mediated by several regulating pathways, like salicylic acid and jasmonic acid. These mediating pathways manipulate different physiological processes like growth and development, stress tolerance, and defence mechanisms of the plant. The assessment of results revealed that among all treatments biochar at 3.25% by weight consistently displayed remarkable effectiveness against the early blight infection by triggering resistance and improving the overall performance of tomato plants. This result is attributed to improved soil health, fastening mineralization as well as absorption processes, and boosting the plant's immunity with the use of a higher concentration of biochar. Hence, it could be recommended for the overall improvement of tomato crop and its sustainability.
... Alternaria spp. are the causal agents of early blight and brown leaf spot, often cited as the most important foliar pathogens of tomato [3,4]. Consistent with the disproportionately high representation of Alternaria spp. in global soils [5], phytopathogenic Alternaria spp. ...
Resistance mechanisms to early blight disease complex (EBDC) in tomato remain obscure given its polygenic and quantitative nature. We investigated the early defense responses of Heinz 1706 tomato to EBDC using RNA-seq. We observed distinct transcriptional reprofiling upon exposure to two EBDC isolates and the PAMP chitin. Avirulent isolate CS046 (Alternaria alternata) elicited a vigorous defense response in the host, whilst the virulent isolate 1117-1 (Alternaria sect. Porri) showed subdued gene expression, suggesting a suppression of defense responses during compatible pathogenesis. We emphasize the specific roles of ETHYLENE RESPONSE FACTORs (ERFs) in defense against EBDC, with a particular focus on the D clade ERFs. Co-expression network analysis revealed the principal genes in early defense responses to EBDC are secondary metabolite biosynthesis genes, transcription factors, and hormone response genes. We constructed a gene regulatory network and predicted novel hub genes as putative global regulators of the defense response, including the D clade ERFs, WRKY, and NAC transcription factors. Our work highlights the failure of virulent EBDC pathogenesis to elicit hormone responses that suppress cell death. Additionally, we found a selective induction for specific ERFs that strongly influence the topology of the EBDC defense transcriptional network.
... Tomato plants require low to medium rainfall. Tomatoes are the world's second-most consumed vegetable after potatoes (Foolad, 2007). Tomatoes are the richest source of vitamins A and C and are loaded with a substance called lycopene. ...
The current study was conducted at the Alutouriya research station under the Agriculture Research Department in the Ministry of Municipality, Qatar, during the years 2020–2021, and 2021–2022, to test the response of various tomato cultivars against early blight. Early blight is the most devastating fungal disease of tomatoes, caused by Alternaria solani. It is one of the most common foliar diseases in tomatoes. The disease can occur in a wide range of climatic conditions but is most prominent in areas with moderate temperatures and high relative humidity. In this study, ten tomato cultivars were evaluated for highly resistant (HR), resistant (R), moderately resistant (MR), moderately susceptible (MS), and susceptible (S) reactions under natural net greenhouse conditions. Alternaria solani produces oblivious green, gray, and brown-to-black colonies when grown on PDA medium. Assessments on the mean percent disease index and severity grade of symptoms were recorded for each cultivar. Only one cultivar, 71 (banana legs), was recorded as moderately susceptible in both years with a high PDI value and symptom severity grade. The cultivars fruit weight for each cultivar was calculated to determine the productivity of the tomato plant. The maximum and minimum temperatures with relative humidity were recorded every week from November to February for the years 2022-2021 and 2021-2020. This data revealed that most of the cultivars used for this study were resistant to early blight.
... This disease is characterized by irregular lesions near the ground, developing yellow patches that darken into concentric black rings and may have a chlorotic region surrounding the lesion. The whole foliage is destroyed by this disease, which spreads quickly to other plants [9]. Despite the fact that early blight may develop in any kind of weather, it prefers moist environments like persistent rain or even heavy dews. ...
... Typically detected on newly developed leaves in the plant canopy, irregularly formed, water-soaked lesions are the earliest signs of late blight on tomato leaves. As the disease worsens, lesions become larger, and the affected leaves turn brown, shrivel, and die [9]. ...
Early diagnosis and treatment of tomato leaf diseases increase a plant's production volume, efficiency, and quality. Misdiagnosis of disease by farmers can lead to an inadequate treatment strategy that hurts the tomato plants and agroecosystem. Therefore, it is crucial to detect the disease precisely. Finding a rapid, accurate approach to take care of the issue of misdiagnosis and early disease identification will be advantageous to the farmers. This study proposed a lightweight custom convolutional neural network (CNN) model and utilized transfer learning (TL)-based models VGG-16 and VGG-19 to classify tomato leaf diseases. In this study, eleven classes, one of which is healthy, are used to simulate various tomato leaf diseases. In addition, an ablation study has been performed in order to find the optimal parameters for the proposed model. Furthermore, evaluation metrics have been used to analyze and compare the performance of the proposed model with the TL-based model. The proposed model, by applying data augmentation techniques, has achieved the highest accuracy and recall of 95.00% among all the models. Finally, the best-performing model has been utilized in order to construct a Web-based and Android-based end-to-end (E2E) system for tomato cultivators to classify tomato leaf disease.
... However, they have reported seven QTL from the chromosomes 3, 4, 5, 6, 8, 10 and 11 in a population derived from the same parents (NC84173 (S) x PI126445 (R) but a different generation [74]. A summary of these information is reported by [75]. A more recent molecular mapping research is summarized in Table 2. ...
... It is reported that multiple genes are involved in tomatoes conferring resistance to early blight (EB) [75,[83][84][85]. Top emphasis was placed on improving early blight resistance in tomatoes since the beginning of the systematic tomato breeding program. ...
... Unfortunately, crossing between cultivated tomato and wild species is very difficult. When it can be achieved, the resulting SLS resistance in progeny are often linked with traits unfit for commercial production [75]. A study exploring the SLS resistance of various Solanum accessions found that the most susceptible accessions tested were cultivated tomatoes (S. lycopersicum and S. lycopersicum var. ...
Foliar fungal diseases in tomatoes include early blight (Alternaria linariae), Septoria leaf spot (Septoria lycopersici), and late blight (Phytophthora infestans) which is oomycetes. These are one of the significant production constraints in tomatoes. We describe the etiology, host range, distribution, symptoms, and disease cycle to understand the biology followed by management practices emphasizing the resistance breeding approach for these diseases. In crop improvement efforts, we provide an analytical review, including conventional and molecular methods for improving this disease resistance. Modern breeding tools, including genomics, genetic transformation, and genome editing, can be used to improve these traits. There is a good possibility of using these tools in the future to improve these traits.
... Nevertheless, in detached leaf assays only 9 lines were highly resistant. This situation occurs due to low-spread of the pathogen throughout the field, which could be result in disease escape: i.e., a perplexing factor in field screening (Foolad et al. 2008). Therefore, the artificial detached leaf method is the way to ascertain resistant sources against late blight disease. ...
The leaf curl disease (ToLCD), late blight (LB) and root knot nematode (RKN) are the major obstacles for rainy season tomato production all over the world. Several tactics are being considered for the management of these diseases. Reportedly, the most efficient way to manage these multiple diseases is to adopt resistant cultivars. Though, work on development of resistant cultivars against multiple diseases are very confined due to non-availability of the resistant sources. In the present study, BC2F6 population comprising 132 elite tomato lines were evaluated using different screening techniques including marker assisted selection (MAS) during 2019–2020 and 2020–2021. Punjab Chuhhara (check) was used as susceptible for all three diseases, while PVB-4, LBR-10 and NR-14 were the resistant checks for ToLCD, LB and RKN, respectively. The lines which showed resistance and moderately resistance responses under field and artificial conditions were exposed for MAS of major resistant genes (Ty-1, Ty-2, Ty-3, Ph-2, Ph-3 and Mi-1.2). PDRT-104, PDRT-118, PDRT-122, PDRT-124 and PDRT-125 were found to provide multiple disease resistant. There was significant correlation between the phenotypic and genotypic based screening. The resistant lines identified in the present evaluation can be utilized to develop cultivars for potential durable resistance to multiple diseases.
... Te mating types are compatibility types, diferentiated by mating hormones, but are not dimorphic forms. When the mycelia of type A1 and A2 mating types interact, the mating hormones induce gametangial formation in the opposing mating types, initiating sexual propagation by means of oospore formation [29]. Te mycelia undergo meiosis during gametangia formation to form antheridia and oogonia that are haploid. ...
Alternaria solani and Phytophthora infestans cause early and late blight diseases in tomato and potato, respectively. A. solani can survive for more than a decade in the soil, seed, or in plant residues at optimum temperature. The pathogen exhibits high molecular and genetic variation between isolates from potato and tomato plants, in different countries. Morphological studies reveal separate conidia borne singly on simple conidiophores. Spores are elongated, muriform, beaked, septate, and dark coloured. The mycelia are branched and septate. A. solani demonstrated a high genetic variability among isolates originating from the United States, Greece, Cuba, Canada, Russia, Turkey, South Africa, Brazil, and China based on vegetative compatibility groups and molecular markers (random amplified polymorphic DNA markers, random amplified microsatellite markers, and amplified fragment length polymorphisms). Different morphological and molecular variations indicate the presence of variability among the isolates. On the other hand, P. infestans is a diploid, obligate, heterothallic, and biotrophic oomycete, whose asexual lifecycle is characterized by alternating phases of sporangia germination, hyphal growth, and sporulation. The mycelia of P. infestans is coenocytic, multinucleate, and aseptate although the cross walls do not form in old cultures. Sporangia are borne singly on the branch tips of the alternately branched sporangiophore. Sporangium is hyaline and lemon shaped with a papilla at the distal end. Mating types A1 and A2 with different clonal lineages have been discovered in various parts of the world indicating variation in the species.
