Water salinity is one of the major abiotic stresses, and the use of saline water for the agricultural sector will incur greater demand in the coming decades. Recently, nanoparticles (NPs) have been used for developing numerous plant fertilizers as a smart and powerful form of material with dual action that can alleviate the adverse effects of salinity and provide the plant with more efficient nutrient forms. This study evaluated the influence of calcium phosphate NPs (CaP-NPs) as a soil fertilizer application on the production and bioactive compounds of broad bean plants under salinity stress. Results showed that salinity had deleterious effects on plant yield with 55.9% reduction compared to control. On the other hand, CaP-NPs dramatically improved plant yield by 30% compared to conventional fertilizer under salinity stress. This improvement could be attributed to significantly higher enhancement in total soluble sugars, antioxidant enzymes, proline content, and total phenolics recorded use of nano-fertilizer compared to conventional use under salt stress. Additionally, nano-fertilizer reflected better mitigatory effects on plant growth parameters, photosynthetic pigments, and oxidative stress indicators (MDA and H2O2). Therefore, our results support the replacement of traditional fertilizers comprising Ca2+ or P with CaP-nano-fertilizers for higher plant productivity and sustainability under salt stress.

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.

During the 2017-2018 growing season, an unusual disease was observed in tomatoes grown in different locations in Fayoum, Giza, and Nobaria in Egypt. A total of 36 naturally infected tomato plants consists of twenty asymptomatic and sixteen symptomatic tomato leaf samples showing interveinal yellowing, reddish-bronze necrosis, downward rolling and bronzing symptoms, early senescence, leaf brittleness, interveinal were collected. All samples were tested with DAS-ELISA using polyclonal and/or monoclonal antisera against several important tomato viruses. The obtained results revealed that, 5 out of 36 samples, were singly infected with tomato chlorosis virus (ToCV) and one sample was singly positive for begomovirus. Potato virus Y (PVY), cucumber mosaic virus (CMV), tobacco mosaic virus (TMV), and pepino mosaic virus (PeMV) were singly detected in 4, 3, 4 and one out of 36 samples, respectively. Two samples had mixed infection of PVY with CMV and TMV with PVY. Reverse-transcriptase polymerase chain reaction results revealed that ToCV was detected in 5 ELISA positive samples, giving a 463 bp ToCV-specific DNA fragment while only one sample was amplified (587 bp) with begomoviruses primers. Sequence analyses of 27 ToCV isolates obtained from GenBank and compared with the five isolates found in this study. All the Egyptian isolates shared high nucleotide identity among themselves (96.8-100%), while their identity matched 93.4-100% with those published in NCBI-GenBank. There was low genetic diversity between all ToCV isolates examined. To our knowledge, this is the first analytical study regarding the presence of ToCV in tomato crops in Egypt.

Phytoplasma-related symptoms such as big bud, witches' broom, phyllody, virescence, flower proliferation, little leaves, yellowing, and stem fasciation were observed in 9 plant species during a field survey in Fayoum Governorate, Egypt, in 2021 and 2022. Disease incidence on various crops ranged from 1 to 21.3% in 2021, with the percentage rising in 2022. In 2022, the highest incidence percentage (23 %( was recorded on sesame while on cowpea the lowest percentage of incidence was recorded being (1.2%). A nested PCR assay employing the universal primer pair P1/P7 followed by R16F2n/R16R2 was used to detect the presence of phytoplasmas by amplifying a segment of the phytoplasma 16S rRNA gene. The resulting amplicons were purified and sequenced. The sequences were deposited in GenBank. Sequence comparison, phylogenetic study, and virtual RFLP analysis of 16S rRNA indicated the presence of diverse phytoplasma ribosomal groups and subgroups infecting different crops (16SrVI-A, 16SrIII-A, 16SrII-D, 16SrII-A, 16SrI-A, and 16SrI-B). The 16SrVI-A phytoplasmas were detected in symptomatic tomato plants, the 16SrII-D phytoplasmas subgroup was identified in sesame, faba bean, and cowpea exhibiting phyllody symptoms, the 16SrII-A subgroup was detected in cauliflower. The 16SrIII-A and 16SrI-A phytoplasmas subgroups were identified in alfalfa witches' broom and chamomile, respectively for the first time in Egypt. Moreover, subgroup 16SrI-B was detected for the first time in Egypt in chrysanthemum and cabbage. This study showed the genetic diversity of phytoplasma strains infecting a variety of crops in Fayoum Governorate.