Phytoplasmas are obligate cell-wall-less plant pathogenic bacteria that infect many economically important crops, causing considerable yield losses worldwide. Very little information is known about phytoplasma–host plant interaction mechanisms and their influence on sesame yield and oil quality. Therefore, our aim was to explore the ultrastructural and agro-physio-biochemical responses of sesame plants and their effects on sesame productivity and oil quality in response to phytoplasma infection. Sesame leaf samples exhibiting phyllody symptoms were collected from three experimental fields during the 2021 growing season. Phytoplasma was successfully detected by nested- polymerase chain reaction (PCR) assays using the universal primer pairs P1/P7 and R16F2n/R16R2, and the product of approximately 1200 bp was amplified. The amplified product of 16S rRNA was sequenced and compared with other available phytoplasma’s 16S rRNA in the GenBank database. Phylogenetic analysis revealed that our Egyptian isolate under accession number MW945416 is closely related to the 16SrII group and showed close (99.7%) identity with MH011394 and L33765.1, which were isolated from Egypt and the USA, respectively. The microscopic examination of phytoplasma-infected plants revealed an observable deterioration in tissue and cell ultrastructure. The primary and secondary metabolites considerably increased in infected plants compared with healthy ones. Moreover, phytoplasma-infected plants showed drastically reduced water content, chlorophyll content, growth, and yield components, resulting in 37.9% and 42.5% reductions in seed and oil yield, respectively. The peroxide value of the infected plant’s oil was 43.2% higher than that of healthy ones, suggesting a short shelf-life. Our findings will provide a better understanding of the phyllody disease pathosystem, helping us to develop effective strategies for overcoming such diseases.

Phytoplasmas are economically important plant pathogenic bacterial diseases, causing severe yield losses worldwide. In this study, we tested nanoformulations such as glycyrrhizic acid ammonium salt (GAS), salicylic acid (SA), and boric acid (BA) as novel antimicrobial agents inducing the resistance against the phytoplasma disease in faba bean. The nanoparticles (NP) were foliar-applied to naturally phytoplasma-infected faba bean with three concentrations from each of SA, GAS, and BA, under field conditions. Nested PCR (using universal primer pairs P1/P7 and R16F2n/R16R2) were reacted positively with all symptomatic samples and gave a product size of approximately 1200 bp, while the healthy plant gave no results. Transmission electron microscopy examinations of phytoplasma-infected faba bean plants treated with different nanoparticles revealed that severe damage occurred in phytoplasma particle’s structure, degradation, malformation, lysis in the cell membrane, and the cytoplasmic leakage followed by complete lysis of phytoplasma cells. Exogenous application of GAS-NP (1.68 µM), SA-NP (0.28 µM), and BA-NP (0.124 µM) suppressed the infection percentage of phytoplasma by 75%, 50%, and 20%, and the disease severity by 84%, 64%, and 54%, respectively. Foliar application of nanoparticles improved Fv/Fm (maximum quantum efficiency of PSII Photochemistry), PI (the performance index), SPAD chlorophyll (the relative chlorophyll content), shoots height, and leaves number, thus inducing recovery of the plant biomass and green pods yield. The most effective treatment was GAS-NP at 1.68 µM that mediated substantial increases in the shoots’ fresh weight, shoots’ dry weight, number of pods per plant, and green pods yield by 230%, 244%, 202% and 178%, respectively, compared to those of infected plants not sprayed with nanoparticles. This study demonstrated the utility of using nanoparticles, particularly GAS-NP at 1.68 µM to suppress the phytoplasma infection.

The second sugar crop of sugar production after sugar cane worldwide is sugar beet (Beta vulgaris L.). This plant is subjected to the infestation of several insect pests that cause considerable damage, especially leafhoppers, that can transmit phytopathogens (e.g., phytoplasma). In this work, we identified and described the leafhopper, Hebata (Alboneurasca) decipiens, in addition to detection and molecular identification of Candidatus Phytoplasma that was transmitted by this leafhopper on sugar beet plants from naturally infected sugar beet plants to an uninfected one. The 16S rDNA gene from phytoplasma was amplified by a nested polymerase chain reaction (PCR) assay and directly sequenced using specific primer pairs DNA fragments. The resulting sequences were analyzed and compared with another phytoplasma sequence available at GenBank sequences performing BLAST using DNAMAN.

In September 2023, yellow blotches, slight leaf malformation, stunting, flower color alteration and thickened bark above the phloem interruption point symptoms, as a virus or phytoplasma-like infection, were observed on Jasminum sambac L. plants in Ismailia and Giza governorates, Egypt. Collected samples were tested by direct ELISA, using the available antisera specific for AMV, PVY, ToRSV, PVX, PLRV, TMV, CMV, ToMV, and TYLCV; however, all tests were fruitless (negative). To diagnose these symptoms as phytoplasma-associated, Dienes' stain was used, followed by examination under incident light microscopy of the Jasminum sambac L. plants. Blue-stained areas were clearly obcerved in the infected phloem tissues, indicating the presence of phytoplasma while we did not notice those blue areas in the healthy phloem (control). Furthermore polymerase chain reaction (PCR) was used successfully with positive results. The amplified products of nested PCR were purified and then sequenced. Sequencing and phylogenetic analysis were performed to identify the detected phytoplasmas. The partial sequence was conducted by the NCBI GenBank database with accession number PP970365, and its definition was 'Jasminum sambac L.' phytoplasma clone PVIDL 16S ribosomal RNA gene, partial sequence with Taxonomy ID: 2030933. Phylogenetic analysis showed a high similarity (97%) with Candidatus Phytoplasma sp.16Sr-IID isolates. Phytoplasma affects plants through different mechanisms, and so, the extent of the effect of phytoplasma on individual Jasminum sambac L., plants was studied in terms of anatomical and biochemical studies to demonstration the relationship between plant defense and effect of phytoplasma on histological and cytological changes, and subsequently, biochemical changes. This study aims to provide the first documentation of the morphological symptoms of phytoplasma infection of Arabian jasmine (Jasminum sambac L.) by the plesiidae insect. This plant is cultivated in Egypt for ornamental, aromatic, and medicinal purposes. The study also aims to achieve molecular confirmation of phytoplasma infection using polymerase chain reaction (PCR), deposit the extracted sequence in GenBank, and characterize the phytoplasma strain and its evolutionary relationships. Furthermore, it seeks to determine the plant's defense mechanisms and resistance, the effects of the disease on the plant, and its pathological indicators, thus contributing to the integrated management of this disease in ornamental plants in general and jasmine in particular.

Bean yellow mosaic virus (BYMV) is one of the most destructive viral diseases affecting leguminous crops, causing severe yield losses. This study aimed to evaluate the potential activity of Clitoria ternatea flower extracts both alcohol and aqueous at different concentrations as a novel method to manage BYMV infection in faba bean plants. The incidence of BYMV was recorded in four governorates (Fayoum, Beheira, Giza, and Bani Suef) during the 2022 growing season to determine the epidemiology of the virus, with infection rates ranging from14.4 to 46.4%. BYMV was isolated and identified based on the symptoms, host range and molecular techniques. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect BYMV, 54 out of 95 samples gave positive results, amplicons were approximately 907bp using specific BYMV primer and 335bp with degenerate primer. Sequence analysis of the Egyptian isolate (Accession No. PP481923) showed identity ranging from 90.8% to 98.3% compared with ten BYMV sequences in GenBank. Various treatments with C. ternatea flower extracts were applied. Results demonstrate that the application of C. ternatea extracts, particularly the alcohol extract in protective treatment at a concentration of 3% effectively eliminated virus-induced symptoms, improved growth parameters, and enhanced photosynthetic pigments in infected faba bean plants compared to the untreated infected control. These results were confirmed by real-time RT-PCR. The flower extracts haven’t been previously used to manage plant viruses, while they have been used to resist human viruses i.e. Coronaviruses. Using C. ternatea flower extracts is a promising eco-friendly and alternative control method against BYMV.