A survey in Poland and China found that strawberries had the highest frequency of multiple pesticide residues. In the current study, insecticides were highly prevalent in vegetables and fruits . Some insecticides appeared one time and others were detected several times. Chlorantraniliprole is one of the insecticides detected one time only in apple. This insecticide is one of the diamide insecticides that are widely used against a variety of insect pests due to their selectivity and low mammalian toxicity. Tian et al. determined diamide insecticides in mushrooms and found that these insecticides can be effectively analyzed using HPLC-MS/MS with LOD and LOQ of 0.05 and 5 ug kg−1 , respectively, and recovery rates ranging from 73.5–110.2%. On the other hand, chlorpyrifos is an insecticide that was detected several times in the tested vegetable and fruit samples. Although this insecticide is recommended in Egypt against almond worms in cotton and termites in buildings according to the approved recommendations for agricultural pest control , it was detected in vegetables and fruits collected from farmers’ markets . This insecticide is no longer approved by European Commission due to harmful effects on different organs. In spite of that, it is still detected in a high percentage in many samples of fruits and vegetables, which is consistent with the results obtained in this study. Fungicides were detected in fruits in a higher percentage than in vegetables . The fungicide pyraclostrobin was detected in grapes only . The dissipation rate of this fungicide was studied in strawberry in Egypt when treated with the recommended field rate. It was found that 82% of this fungicide degraded within 14 days of treatment with a half-life of 5 days. In contrast, container growing raspberries the fungicide thiophanate-methyl was detected in four vegetable samples and in six fruit samples as recorded in Tables 1 and 2.

As this fungicide is widely used in the control of a variety of pathogens pre- and post-harvest, it was detected in many vegetable and fruit samples, herbal medicine, raisins, salmon, beebread, and also in cow and human milk. Samples of cucumber and apples were found to have ≥15 pesticide residues . Chlorpyrifos and lamda-cyhalothrin were detected in more than 15 samples with some values higher than MRLs. In our study, pesticide residues exceeding MRLs in vegetables and fruits were 41 and 39%, respectively. Other studies showed the same results, i.e., in Mwanja et al., pesticide residues were detected in 63.3% of the tested vegetable and fruit samples with residue levels exceeding MRLs of the codex Alimentarius in cabbage, tomato, and orange samples. Further, in the study of Hamed et al., residues of pesticides in apples and grapes from Egypt were determined and they reported that 12.7 and 16.4% of pesticide residues exceeded the MRLs, which was slightly lower than what we found in the current study . Consistent with our findings, a study conducted by Parveen et al. in Pakistan reported that pesticide residues in apple and grape samples exceeded MRLs with 28 and 20%, respectively. Estimation of pesticide residues in imported food is necessary to know about food safety. A study in the United Kingdom for monitoring levels of pesticide residues in imported foods from different countries showed that 51.3% of Egypt samples, compared to 77% , 68.3% , 55.1% , 46.1% , and 45.7% contained detectable pesticide residues. They recorded that India, Kenya, Brazil, Egypt, Chile, and the United States were countries with residue levels exceeding MRLs in 18.1%, 11.4%, 7.8%, 5.1%, 3.2%, and 2%, respectively. In the same context, Osaili et al. determined pesticide residues in samples of imported vegetables to the United Arab Emirates.

They found that 30.5% pesticide residues higher than MRLs in total imported samples and found 14% of the Egyptian samples compared to 47%, 33%, 13%, and 43% from India, United Kingdom, China, and Sri Lanka, respectively, contained residues higher than MRLs. The results of monitoring pesticide residues in fruits and vegetables showed that some samples had residues that exceed the MRL standard, which may lead to risks when consuming food contaminated with these pesticides. In addition, some pesticides do not have corresponding residual limits, which make it difficult for farmers to safely use these pesticides and for the government to monitor their use. Therefore, identification of acute and chronic dietary risks is necessary to assess the risks associated with consuming vegetables or fruits that contain pesticide residues above the MRLs. In this regard, Chu et al. evaluated the risks of food exposure to 26 insecticides on strawberries and found that despite the presence of high detection rates for these residues, they showed risks of acute and chronic exposure at a level of less than 100%. In our results of risk assessment, residues of lambda-cyhalothrin, fipronil, dimothoate, and omethoate were found to have acute or chronic risks in consumers in the case of consuming 100 or 200 gm day−1 of spinach, zucchini, kaki, and strawberry, respectively . In line with our findings, the results of Tao et al., 2021 showed that the fungicide carbendazim had a risk quotient value of 2.9 in wheat flour samples, indicating an unacceptable dietary risk. Furthermore, Tankiewicz and Berg showed that pesticides of lambda-cyhalothrin in courgettes, captan in apples and cucumbers, dimethoate in cour-gettes, and linuron in carrots exceeded the MRLs and pose a health risk. In an Indian study conducted by Sinha et al., they stated that excessive application of pesticides on grapes cause adverse health effects in developing countries as grapes and apples are contaminated with different classes of pesticides including organophosphate, which cause high health risks for consumers.

In this context, Javeres et al. showed that the prolonged exposure to insecticides could lead to physiological disorders including high blood pressure, hyperglycemia, overweight or dyslipidemia, which may cause metabolic syndrome and other chronic diseases. For these adverse effects, it is important in each country to monitor pesticide residues in food for food safety and human health.Tomato is the world’s second largest vegetable crop rich in nutrients. Tomato fruit development includes three stages. The first stage is characterized by an increase in cell number and starch accumulation, followed by cell enlargement with starch degradation and soluble sugar accumulation in the second stage. Fruit ripening is the last stage, associated with the accumulation of soluble sugars, carotenoids, organic acids, and volatile organic compounds in fruits. The chlorophyll accumulation and photosynthetic activity of green fruits influence the nutritional components and flavor of ripening tomato fruits. Some genes have been reported to affect chlorophyll accumulation, chloroplast development and fruit quality. As negative regulators, DE-ETIOLATED 1/high pigment 2 and UV-DAMAGED DNA-BINDING PROTEIN 1/ high pigment 1 are involved in chloroplast formation and chlorophyll accumulation in tomato fruits. The tomato GOLDEN2-LIKE transcription factors SlGLK1 and SlGLK2 play an important role in chloroplast formation and chlorophyll accumulation.Evidence suggests that the SlGLK2 gene is predominantly expressed in fruits and that the latitudinal gradient of SlGLK2 expression influences the production of unevenly colored tomato fruits. Over expression of the APRR2- LIKE gene, the closest homolog of SlGLK2, increased the size and number of chloroplasts and enhanced chlorophyll accumulation in green tomato fruits. TKN2 and TKN4, two Class I KNOTTED1-LIKE HOMEOBOX proteins, act as transcriptional activators of SlGLK2 and APRR2-LIKE genes to promote chloroplast development in tomato fruits. BEL1-LIKE HOMEODOMAIN11 also plays an important role in chlorophyll synthesis and chloroplast development in tomato fruits. The ripening of tomato is mainly regulated by the ethylene pathway and many transcription factors. In the ethylene bio-synthetic pathway, S-adenosylmethionine synthetase catalyzes the reaction of ATP and methionine to form S-adenosyl-L-methionine. 1-Aminocyclopropane-1-carboxylic acid synthase and ACC oxidase catalyze the conversion of SAM to ACC and of ACC to ethylene, respectively. The MADS box gene RIPENING INHIBITOR controls the early phase of ripening and ethylene production via transcriptional regulation of ACSs and ACOs. The other ripening regulators affecting ethylene production also include the NAC transcription factor NOR, the SQUAMOSA PROMOTER BINDING protein CNR, blueberries in pots the ethylene response factor ERF B3, the AP2/ERF member AP2a, and several MADS box proteins, such as TDR4/SlFUL1, SlFUL2, SlMADS1, TAGL1, and TAG1.

Auxin is an important phytohormone involved in flower fertilization, fruit setting, fruit initiation and development. Auxin is also essential in the regulation of cell division and expansion, controlling final fruit size. Auxin modulates plant development through transcriptional regulation of auxin-responsive genes, which is primarily mediated by two gene families: the short-lived nuclear protein Aux/IAA family and auxin response factors. Most ARFs have an N-terminal DNAbinding domain required for transcriptional regulation of auxin response genes, a middle region functioning as a repression domain or activation domain , and a C-terminal dimerization domain involved in the formation of homodimers or heterodimers. ARFs can act as either an activator or a repressor of the transcription of auxin-responsive genes. Numerous studies have indicated that ARFs are involved in many tomato developmental processes. SlARF4 negatively regulates chlorophyll accumulation and starch biosynthesis in tomato fruit. Our previous study showed that SlARF10 positively regulated chlorophyll accumulation via direct activation of the expression of SlGLK1. Downregulation of ARF6 and ARF8 by over expression of Arabidopsis microRNA167 results in the failure of pollen germination on the stigma surface and/or growth through the style in tomato. However, the function of SlARF6 in the regulation of fruit development is still not well understood. In this study, SlARF6A was found to be involved in photosynthesis, sugar accumulation and fruit development in tomato. Our data demonstrate that SlARF6A plays an important role in the regulation of fruit quality and development.The SlARF6A gene has an open reading frame of 2608 bp encoding a putative protein of 869 amino acids. Amino acid sequence analysis revealed that, like SlARF7 and SlARF8, which have typical conserved ARF domains, SlARF6A protein also contained B3-DNA, ARF, and AUX/IAA binding domains . A phylogenetic tree was constructed to gain insight into the phylogenetic relationship among ARF proteins in Arabidopsis and tomato. ARFs were divided into four major classes: I, II, III, and VI. SlARF6A along with SlARF6B and AtARF6 were grouped into subclass IIa and are closely related to AtARF8 and SlARF8 , indicating possible functional similarity among them. To determine the expression pattern of SlARF6A in planta, a transcriptional fusion was constructed between the SlARF6A promoter and the GUS reporter gene. GUS staining in the transgenic tomato plants was detected in leaves, stems, buds, flowers, and fruits at different developmental stages, an indication of the ubiquitous expression of SlARF6A in all tissues tested. The GUS staining was weak in the early fruits at 2 and 4 days post anthesis but became strong at 8, 30 and 45 DPA , suggesting possible roles of SlARF6A in the development of tomato fruits. To examine its subcellular localization in plants, SlARF6A was fused to GFP and transferred into tobacco protoplasts. Fluorescence microscopy analysis revealed that SlARF6A was specifically localized in the nuclei . A GAL4-responsive reporter system in yeast was employed to reveal the transcriptional activity of SlARF6A. SlARF6A was fused to GAL4-BD to form a pGBKT7-SlARF6A fusion plasmid and subsequently transformed into yeast. Yeast transformants harboring the pGBKT7-SlARF6A construct grew well in the medium lacking Trp, His, and Ade , while the yeasts transformed with pGBKT7 vector alone could not . Assessing transcriptional activity revealed that SlARF6A is a transcriptional activator.To elucidate the physiological significance of the SlARF6A gene in fruit development, upregulated and downregulated transgenic lines corresponding to independent transformation events were generated in tomato plants. qRT-PCR was used to evaluate the expression level of SlARF6A in all transgenic lines. Compared with thelevel in the wild type , the expression level of SlARF6A was decreased in RNAi 2 and 6 plants but increased in OE-4 and 6 plants . It is noteworthy that altered SlARF6A expression led to a dramatic change in chlorophyll accumulation in transgenic lines. Compared with WT plants, the OE-SlARF6A plants had dark-green fruits at the green fruit stage, whereas the RNAi-SlARF6A plants had light-green fruits . The impact of altered SlARF6A expression on chlorophyll accumulation was analyzed by measuring the chlorophyll content in fruits and leaves. The SlARF6A overexpression lines possessed greater accumulation of chlorophyll in the fruits at immature green, mature green, breaker, and orange stages, whereas the RNAi lines had lower chlorophyll accumulation in the fruits at immature green and mature green stages than the WT plants .