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.

This review provides a critical summary of the biological remediation of heavy metals by leveraging the potential of microbes in soils and water ecosystems, highlighting major research findings and practical obstacles. Heavy metals (HMs) pose a severe threat to environmental health due to their toxicity and persistence, necessitating effective remediation strategies. Biological remediation, especially through microorganisms and enzymatic actions, offers a promising alternative to conventional methods due to its eco-friendly and cost-effective nature. The review discusses various microbes, including bacteria, fungi, and algae known for their metal-binding capacities and transformation abilities. It delves into the mechanisms of bioremediation, such as biosorption, bioaccumulation, and biotransformation, facilitated by microbial enzymes like oxidoreductases and hydrolases that remove or bind the chemical structure of HMs. This paper also explores genetic engineering approaches to enhance microbial efficacy in HMs’ uptake and resistance. Furthermore, the review addresses the significant challenges in scaling bioremediation from a laboratory to the field, such as the complexity of environmental conditions, the presence of mixed contaminants, and the need for system optimization to improve efficiency and sustainability. It also evaluates the current legislative framework governing bioremediation practices, suggesting a need for clearer policies to support the integration of biological methods into mainstream remediation strategies. Conclusively, while microbial and enzymatic remediation presents considerable potential, extensive research is needed to overcome existing hurdles and develop robust, field-applicable systems. This paper calls for a multidisciplinary approach combining microbiology, engineering, and environmental sciences to advance this promising field.

Late blight disease, caused by Phytophthora infestans (Mont.) de Bary, is one of the most challenging diseases threatening tomato production and other Solanaceae crops. Resistance to late blight is found in certain wild species, but the mechanism behind the resistance is not fully understood. The aim of this study was to examine the metabolic profiles in the leaf tissue of late blight-resistant wild tomato and to investigate if leaf extracts from such genotypes could be used to control late blight in tomato production. We included three recognized late blight-resistant wild tomato accessions of Solanum habrochaites (LA1777, LA2855, and LA1352) and two recognized highly susceptible genotypes, S. lycopersicum (‘Super Strain B’) and S. pimpinellifolium (LA0375). The metabolic profiles were obtained in both inoculated and non-inoculated plants by analyzing leaf extracts using high-resolution gas chromatography-mass spectrometry (GC-MS) with three replicate analyses of each genotype. We focused on volatile organic compounds (VOCs) and identified 31 such compounds from the five genotypes with a retention time ranging from 6.6 to 22.8 min. The resistant genotype LA 1777 produced the highest number of VOCs (22 and 21 in the inoculated and control plants, respectively), whereas the susceptible genotype ‘Super Strain B’ produced the lowest number of VOCs (11 and 13 in the respective plants). Among the VOCs, 14 were detected only in the resistant genotypes, while two were detected only in the susceptible ones. In vitro trials, with the use of a detached leaflet assay and whole-plant approach, were conducted. We revealed promising insights regarding late blight management and showed that metabolic profiling may contribute to a better understanding of the mechanisms behind P. infestans resistance in tomato and its wild relatives.

In the current study, evaluation the ability of three isolates of Sclerotium rolfsii isolated from tomato, bean and cabbage to infect their host plants and two non-host plants was carried out. Tomato plants were strongly affected with the three isolates of the pathogen followed by cabbage plants, whereas common bean plants were the least in this respect. Six species of Trichoderma were examined for their bio-control potentials against S. rolfsii the causative of root rot in tomato, common bean and cabbage. In vitro antagonistic test showed that T. koningii exhibited high inhibitory effect as the percentage of inhibition value was higher in case of S. rolfsii (tomato isolate) followed by T. harzianum with S. rolfsii (bean isolate) and S. rolfsii (cabbage isolate). Under greenhouse conditions; T. koningii, T. viride and T. harzianum showed the highest antagonistic effect against the three isolates of S. rolfsii in pots experiment. Microscopic examinations showed that most of Trichoderma spp. grew over mycelia of the tested pathogen with surrounded, coiling, lysis of hyphae and collapse of mycelium. T. koningii and T. viride exhibited the best performance regarding to the defense enzyme secretion; chitinase and β-glucanase followed by T. harzianum. Also, all the tested Trichoderma spp. produced Indole acetic acid (IAA) and Gibberellic acid (GA) as a plant growth promoting substances in variable values.

Cucumber as an important vegetable crop faces a variety of abiotic and biotic stresses, especially the recently appeared fungicide-resistant strains of Pseudoperonospora cubensis, the causal agent of downy mildew disease. Herein, the present study aimed to evaluate the effect of Trichoderma asperellum strain T34 as a biological commercial product and potassium phosphite (KPHI) against P. cubensis and investigate the ability of these compounds to activate the plant defense system to suppress P. cubensis infection. In two separate experiments, the foliar applications with T34 or KPHI significantly reduced the severity of downy mildew disease and the area under the disease progress curve compared to water control. Scanning electron microscopy (SEM) of P. cubensis treated with T34 and KPHI showed shrunken and distorted sporangiophores and sporangia. Moreover, two tested compounds enhanced cucumber plants’ growth and yield parameters under greenhouse conditions. The tested compounds protected the membrane permeability of infected cucumber leaves and significantly reduced electrolyte leakage (EL %) compared to water control. These findings were associated with activating enzymatic antioxidant enzymes (catalase, peroxidase, and polyphenol oxidase). Our findings suggest that T34 and KPHI can be environmentally safe alternatives to chemical fungicides to control downy mildew disease in cucumber and other cucurbit crops.