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Citrus Research and Education Center

Citrus Research and Education Center

Publications - Dr. Ahmad Omar


Publications

Peer-reviewed Research

Oraby HF, Elnaggar NZ, Omar AA, Mohamed AH (2025) Role of Serotonin in Cadmium Mitigation in Plants. Plants 14 (12). https://doi.org/10.3390/plants14121738

Jia H, Omar AA, Xu J, Dalmendray J, Wang Y, Feng Y, Wang W, Hu Z, Grosser JW, Wang N (2024) Generation of transgene-free canker-resistant Citrus sinensis cv. Hamlin in the T0 generation through Cas12a/CBE co-editing. Front Plant Sci 15:1385768. https://doi.org/10.3389/fpls.2024.1385768

Su H, Wang Y, Xu J, Omar AA, Grosser JW, Wang N (2024) Cas12a RNP-mediated co-transformation enables transgene-free multiplex genome editing, long deletions, and inversions in citrus chromosome. Front Plant Sci 15:1448807. https://doi.org/10.3389/fpls.2024.1448807

Grosser, J.W., F.G. Gmitter, \, J. Chater, M. Dutt, A. Omar, and L.M. Cano. 2024. Citrus rootstock breeding in an HLB-endemic environment with an industry in crisis. Italus Hortus 31:73-78. https://doi.org/10.26353/j.itahort/2024.1.7378.

Ikram, M., N.I. Raja, A.H. Mohamed, Z.-U.-R. Mashwani, A.A. Omar, H. Gharibi, and R.A. Zubarev. 2024. Differential impact of plant-based selenium nanoparticles on physio-biochemical properties, antioxidant defense system and protein regulation in fruits of huanglongbing-infected ‘Kinnow’ mandarin plants. Frontiers in Plant Science 15.  https://doi.org/10.3389/fpls.2024.1476497

Rizk, R., E. Zayed, A. Amin, A. Omar, and H. Oraby. 2024. Effectiveness of DNA barcoding, SCOT markers and phytochemical characterization in biodiversity assessment of some Zea mays hybrids. SOUTH AFRICAN JOURNAL OF BOTANY 165:59-69. https://doi.org/10.1016/j.sajb.2023.12.020.

Jabeen S, Qureshi R, Ikram M, Omar AA, Hussain M, Elnaggar N, Oraby HF (2023) Phyto-fabrication and characterization of silver nanoparticles using Withania somnifera: Investigating antioxidant potential. Green Process Synth 12 (1). https://doi.org/10.1515/gps-2023-0167

Omar AA, Heikal YM, Zayed EM, Shamseldin SAM, Salama YE, Amer KE, Basuoni MM, Abd Ellatif S, Mohamed AH (2023) Conferring of Drought and Heat Stress Tolerance in Wheat (Triticum aestivum L.) Genotypes and Their Response to Selenium Nanoparticles Application. Nanomaterials 13 (6). https://doi.org/10.3390/nano13060998

Omar AA, Zayed EM, Oraby HF, Elnaggar NZ, Elashtokhy MM, Basuoni MM, Osman A, Shamseldin SA, Attia KA, Mohamed AH (2023) Description of phenotypic, grain quality, molecular fingerprinting, and biodiversity using DNA barcoding of some elite rice genotypes. S Afr J Bot 154:289–299. https://doi.org/10.1016/j.sajb.2023.01.045

Su H, Wang Y, Xu J, Omar AA, Grosser JW, Calovic M, Zhang L, Feng Y, Vakulskas CA, Wang N (2023) Generation of the transgene-free canker-resistant Citrus sinensis using Cas12a/crRNA ribonucleoprotein in the T0 generation. Nature Communications 14 (1):3957. https://doi.org/10.1038/s41467-023-39714-9

Gaikwad PN, Sharma V, Singh J, Sidhu GS, Singh H, Omar AA (2023) Biotechnological advancements in Phytophthora disease diagnosis, interaction and management in citrus. Scientia Horticulturae 310:111739. https://doi.org/10.1016/j.scienta.2022.111739

Ennab HA, Mohamed AH, El-Hoseiny HM, Omar AA, Hassan IF, Gaballah MS, Khalil SE, Mira AM, Abd El-Khalek AF, Alam-Eldein SM (2023) Humic Acid Improves the Resilience to Salinity Stress of Drip-Irrigated Mexican Lime Trees in Saline Clay Soils. Agronomy 13 (7):1680. https://doi.org/10.3390/agronomy13071680

Awad-Allah MMA, Attia KA, Omar AA, Dessoky ES, Alzuaibr FM, Alshehri MA, Abdein MA, Mohamed AH (2022) Development of New Iso-Cytoplasmic Rice-Restorer Lines and New Rice Hybrids with Superior Grain Yield and Grain Quality Characteristics by Utilizing Restorers' Fertility Genes. Genes (Basel) 13 (5):808. https://doi.org/10.3390/genes13050808

Awad-Allah MMA, Attia KA, Omar AA, Mohamed AH, Habiba RM, Alzuaibr FM, Alshehri MA, Alqurashi M, Aloufi S, Dessoky ES, Abdein MA (2022) Combining Ability and Gene Action Controlling Agronomic Traits for Cytoplasmic Male Sterile Line, Restorer Lines, and New Hybrids for Developing of New Drought-Tolerant Rice Hybrids. Genes (Basel) 13 (5):906. https://doi.org/10.3390/genes13050906

Fikry AM, Radhi KS, Abourehab MAS, Abou Sayed-Ahmed TAM, Ibrahim MM, Mohsen FS, Abdou NA, Omar AA, Elesawi IE, El-Saadony MT (2022) Effect of Inorganic and Organic Nitrogen Sources and Biofertilizer on Murcott Mandarin Fruit Quality. Life 12 (12):2120. https://doi.org/10.3390/life12122120

Ikram M, Raja NI, Mashwani Z-U-R, Omar AA, Mohamed AH, Satti SH, Zohra E (2022) Phytogenic Selenium Nanoparticles Elicited the Physiological, Biochemical, and Antioxidant Defense System Amelioration of Huanglongbing-Infected 'Kinnow' Mandarin Plants. Nanomaterials 12 (3):356. https://doi.org/10.3390/nano12030356

Khan M, Mashwani Z-u-R, Ikram M, Raja NI, Mohamed AH, Ren G, Omar AA (2022) Efficacy of Green Cerium Oxide Nanoparticles for Potential Therapeutic Applications: Circumstantial Insight on Mechanistic Aspects. Nanomaterials 12 (12):2117. https://doi.org/10.3390/nano12122117

Satti SH, Raja NI, Ikram M, Oraby HF, Mashwani ZU, Mohamed AH, Singh A, Omar AA (2022) Plant-Based Titanium Dioxide Nanoparticles Trigger Biochemical and Proteome Modifications in Triticum aestivum L. under Biotic Stress of Puccinia striiformis. Molecules 27 (13):4274. http://doi.org/10.3390/molecules27134274

ElSayed AI, Mohamed AH, Rafudeen MS, Omar AA, Awad MF, Mansour E (2022) Polyamines mitigate the destructive impacts of salinity stress by enhancing photosynthetic capacity, antioxidant defense system and upregulation of calvin cycle-related genes in rapeseed (Brassica napus). Saudi J Biol Sci 29 (5):3675–3686. https://doi.org/10.1016/j.sjbs.2022.02.053

Jia H, Omar AA, Orbovic V, Wang N (2021) Generating biallelic canker-resistant ‘Duncan’ grapefruit plant via CRISPR-Cas9. Phytopathology. https://doi.org/10.1094/PHYTO-04-21-0144-R

Mohamed AH, Omar AA, Attya AM, Elashtokhy MMA, Zayed EM, Rizk RM (2021) Morphological and Molecular Characterization of Some Egyptian Six-Rowed Barley (Hordeum vulgare L.). Plants 10 (11):2527. https://doi.org/10.3390/plants10112527

Omar AA, Mahgoub S, Salama A, Likotrafiti E, Rhoades J, Christakis C, Samaras P (2021) Evaluation of Lactobacillus kefiri and manganese peroxidase‐producing bacteria for decolorization of melanoidins and reduction of chemical oxygen demand. Water Environ J 35 (2):704–714. https://doi.org/10.1111/wej.12663

Zohra E, Ikram M, Omar AA, Hussain M, Satti SH, Raja NI, Mashwani Z-U-R, Ehsan M (2021) Potential applications of biogenic selenium nanoparticles in alleviating biotic and abiotic stresses in plants: A comprehensive insight on the mechanistic approach and future perspectives. Green Process Synth 10:456–475. https://doi.org/10.1515/gps-2021-0047

ElSayed AI, Boulila M, Rafudeen MS, Mohamed AH, Sengupta S, Rady M, Omar AA (2020) Melatonin regulatory mechanisms and phylogenetic analyses of melatonin biosynthesis related genes extracted from peanut under salinity stress. Plants 9 (7):854. https://doi.org/10.3390/plants9070854

Killiny N, Jones SE, Hijaz F, Kishk A, Santos-Ortega Y, Nehela Y, Omar AA, Yu Q, Gmitter FG, Grosser JW, Dutt M (2020) Metabolic Profiling of Hybrids Generated from Pummelo and Citrus latipes in Relation to Their Attraction to Diaphorina citri, the Vector of Huanglongbing. Metabolites 10 (12). https://doi.org/10.3390/metabo10120477

Boulila M, ElSayed AI, Rafudeen MS, Omar AA (2020) Investigating molecular evolutionary forces and phylogenetic relationships among melatonin precursor-encoding genes of different plant species. Mol Biol Rep 47 (3):1625–1636. https://doi.org/10.1007/s11033-020-05249-1

Murata, M.M., Omar, A.A., Mou, Z., Chase, C.D., Grosser, J.W., Graham, J.H., 2018. Novel plastid-nuclear genome combinations enhance resistance to citrus canker in cybrid grapefruit. Frontiers in Plant Science, 9:1858. https://dx.doi.org/10.3389%2Ffpls.2018.01858

Omar, A.A., Mohamed, A.H., Nasr, M.I., El-Halafawy, K.A., Alabsawy, E.A., Hamdi, A.I., Zayed, E.M., 2018. Molecular characterization of Soybean (Glycine max L. Merr) genotypes tolerant and susceptible to cotton leaf worm (Spodoptera littoralis). American Journal of Biochemistry and Molecular Biology 8, 34-47. https://doi.org/10.3923/ajbmb.2018.34.47

Omar, A.A., Murata, M.M., El-Shamy, H.A., Graham, J.H., and Grosser, J.W. 2018. Enhanced resistance to citrus canker in transgenic mandarin expressing Xa21 from rice. Transgenic Research. 27:179-191. http://dx.doi.org/10.3923/ajbmb.2018.34.47

Killiny, N., M.F. Valim, S.E. Jones, A.A. Omar, F. Hijaz, F.G. Gmitter Jr, and J.W. Grosser. 2017. Metabolically speaking: Possible reasons behind the tolerance of ‘Sugar Belle’ mandarin hybrid to huanglongbing. Plant Physiol. Biochem. 116:36-47. https://doi.org/10.1016/j.plaphy.2017.05.001

Omar, A.A., M.M. Murata, Q. Yu, F.G. Gmitter, Jr., C.D. Chase, J.H. Graham, and J.W. Grosser. 2017. Production of three new grapefruit cybrids with potential for improved citrus canker resistance. In Vitro Cell. Dev. Biol. Plant. 53:256-269. https://doi.org/10.1007/s11627-017-9816-7

Khalifa, S.A., A.A. Omar, and A.H. Mohamed. 2017. The effect of substituting milk fat by peanut oil on the quality of white soft cheese. International Journal of Dairy Science. 12:28-40. http://doi.org/10.3923/ijds.2017.28.40

ElSayed, A.I., M. Boulila, D.C. Odero, A.A. Omar, A.M. Gomaa, and R. Viswanathan. 2017. Characterization of ORF0 and ORF1 and their Roles in Recombination and Replication of Sugarcane yellow leaf virus. American Journal of Biochemistry and Molecular Biology. 7:41-52. http://dx.doi.org/10.3923/ajbmb.2017.41.52

Ibrahim, M.M., A.O. Mohamed, A.H. Mohamed, and A.A. Omar. 2016. Effect of some girdling treatments on fruiting behavior and physio-chemical properties of Washington navel orange trees. Journal of Agriculture and Veterinary Science. 9:58-65.  https://doi.org/10.9790/2380-0906015865

Zayed, E., M. Sayed, and A.A. Omar. 2015. Genetic variations between two ecotypes of Egyptian clover by inter-simple sequence repeat (ISSR) techniques. African Journal of Biotechnology. 14:1947-1953.  https://doi.org/10.5897/AJB2015.14609

Grosser, J.W., A.A. Omar, J.A. Gmitter, and J.P. Syvertsen. 2012. Salinity Tolerance of ‘Valencia’ Orange Trees on Allotetraploid Rootstocks. Proc. Fla. State Hort. Soc. 125:50-55.

Grosser, J.W., M. Dutt, A.A. Omar, V. Orbovic, and G. Barthe. 2011. Progress towards the development of transgenic disease resistance in citrus. Acta Hort. (ISHS). 892:101-107. https://doi.org/10.17660/ActaHortic.2011.892.12

Dutt, M., A.A. Omar, V. Orbovic, G. Barthe, and J.W. Grosser. 2010. Progress towards incorporation of antimicrobial peptides for disease resistance in citrus. ICC:258-264.

Omar, A.A., A.H. Mohamed, and J.W. Grosser. 2009. Study of transgene expression by phloem-specific promoter in transgenic citrus plant. Journal of Biological Chemistry and Environmental Sciences. 4: 647-661.

Abouziena, H.F., A.A. Omar, S.D. Sharma, and M. Singh. 2009. Efficacy comparison of some new natural product herbicides for weed control at two growth stages. Weed Technol. 23:431-437. https://doi.org/10.1614/WT-08-185.1

Abouziena, H.F., R.A. Elmergawi, S. Sharma, A.A. Omar, and M. Singh. 2009. Zinc antagonizes glyphosate efficacy on yellow nutsedge (Cyperus esculentus). Weed Sci. 57:16-20. https://doi.org/10.1614/WS-08-084.1

Omar, A.A., and J.W. Grosser. 2008. Comparison of endoplasmic reticulum targeted and non-targeted cytoplasmic GFP as a selectable marker in citrus protoplast transformation. Plant Sci. 174:131-139. https://doi.org/10.1016/j.plantsci.2007.10.003

Omar, A.A., M.G.H. Dekkers, J.H. Graham, and J.W. Grosser. 2008. Estimation of Transgene Copy Number in Transformed Citrus Plants by Quantitative Multiplex Real-Time PCR. Biotechnol. Prog. 24:1241-1248. https://doi.org/10.1002/btpr.62

Omar, A.A., W.Y. Song, and J.W. Grosser. 2007. Introduction of Xa21, a Xanthomonas-resistance gene from rice, into 'Hamlin' sweet orange [Citrus sinensis (L.) Osbeck] using protoplast-GFP co-transformation or single plasmid transformation. J. Horticult. Sci. Biotechnol. 82:914-923. https://doi.org/10.1080/14620316.2007.11512326

Omar, A.A., and J.W. Grosser. 2007. Protoplast co-transformation and regeneration of transgenic `Hamlin` sweet orange plants containing a cDNA Xa21 Xanthomonas resistance gene and GFP. Acta Horticulture. 738:235-244. https://doi.org/10.17660/ActaHortic.2007.738.23

Abouziena, H.F., E.R. El-Desoki, S. Sharma, A.A. Omar, and M. Singh. 2007. Evaluation of sowing in hills on ridges as a new technique for enhancement of Wheat (Triticum aestivum, L) Productivity. Egyptian Journal of Agronomy. 29:85-100.

Past Positions

  • Professor (Sabbatical), 2021 – Present, Biochemistry Department, College of Agriculture, Zagazig University, Egypt
  • Associate Professor (Sabbatical), 2016 – 2021, Biochemistry Department, College of Agriculture, Zagazig University, Egypt
  • Postdoctoral Associate, 2011 – 2018, CREC, University of Florida, Lake Alfred FL
  • Assistant Professor, 2009 – 2016, Biochemistry Department, College of Agriculture, Zagazig University, Egypt
  • Postdoctoral Associate, 2006 – 2009, CREC, University of Florida, Lake Alfred FL
  • Research Assistant, 2000 – 2006, CREC, University of Florida, Lake Alfred FL
  • Research Assistant, 1994 – 1999, Biochemistry Department, College of Agriculture, Zagazig University, Egypt
  • Chemist and Researcher, 1993 – 1994, Micro-Analysis Unit, Center Lab, College of Agriculture, Zagazig University, Egypt

Book Chapters

Siddiqa A, Ikram M, Zohra E, Iqbal Raja N, Mashwani Z-U-R, Mohamed AH, Zahedi SM, Abbas A, Omar AA (2023) Overview of Nanomaterials and their Synthesis. In: Mishra KK, Kumar S (eds) Biotic Stress Management of Crop Plants using Nanomaterials. pp 1–19. https://doi.org/10.1201/9781003322122-1

Zohra E, Ikram M, Iqbal Raja N, Mashwani Z-U-R, Omar AA, Mohamed AH, Morteza Zahedi S, Abbas A (2023) Nanomaterials as Nano-Fertilizers. In: Mishra KK, Kumar S (eds) Biotic Stress Management of Crop Plants using Nanomaterials. pp 35–51. https://doi.org/10.1201/9781003322122-3

ElSayed AI, Omar AA (2022) Physiological and Molecular Stress Responses in Sugarcane. In: Gaur RK (ed) Omics Approaches for Sugarcane Crop Improvement. CRC Press, Boca Raton, FL, USA, pp 181–190. https://doi.org/10.1201/9781003292425-10

Soriano L, Omar A.A., Martinelli AP (2022) Citrus Protoplast Isolation and Plant Regeneration Through Somatic Embryogenesis. In: Ramírez-Mosqueda MA (ed) Somatic Embryogenesis: Methods and Protocols. Springer US, New York, NY, pp 111-126. https://doi.org/10.1007/978-1-0716-2485-2_9

Omar A.A., ElSayed AI, Mohamed AH (2022) Tangerine (Citrus reticulata) Wastes: Chemistry, Properties and Applications. In: Ramadan MF, Farag MA (eds) Mediterranean Fruits Bio-wastes. Springer Nature, Switzerland. https://doi.org/10.1007/978-3-030-84436-3_11

Omar AA, ElSayed AI, Mohamed AH (2021) Genetic diversity and ecotypes of Opuntia Spp. In: Ramadan MF, Ayoub TEM, Rohn S (eds) Opuntia spp.: Chemistry, Bioactivity and Industrial Applications. Springer Nature, Switzerland AG. https://doi.org/10.1007/978-3-030-78444-7_8

Omar, A.A., M. Dutt, F.G. Gmitter, Jr., and J.W. Grosser. 2016. Somatic Embryogenesis: Still a Relevant Technique in Citrus Improvement. In In Vitro Embryogenesis in Higher Plants. Vol. 1359. M.A. Germanà and M. Lambardi, editors. Springer, New York. 289-327.

Grosser, J.W., and A.A. Omar. 2011. Protoplasts – an increasingly valuable tool in plant research. In Plant Cell Culture, Development and Biotechnology. R.N. Trigiano and D.J. Gray, editors. Taylor and Francis (CRC Press, LLC), Boca Raton, Florida.

Edited Books

Abdel Latef AA, Zayed EM, Omar AA (eds) (2025) Bioremediation and Nanotechnology for Climate Change Mitigation. Springer Nature, Cham, Switzerland. https://doi.org/10.1007/978-981-96-3069-1

Abdel Latef AA, Zayed EM, Omar AA (eds) (2025) Sustainable Remediation for Pollution and Climate Resilience. Springer Nature, Cham, Switzerland. https://doi.org/10.1007/978-981-96-5674-5

 

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