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Prof. Abdullah Al-Sadi
Sultan Qabbos university

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0 fungal diversity
0 Integrated Disease Management
0 phytoplasma
0 Plant pathology, Fungi
0 Biocontrol against fungal pathogens

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phytoplasma
fungal diversity
Integrated Disease Management

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Journal article
Published: 30 July 2021 in Sustainability
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Sunflower (Helianthus annuus L.), a member of the Asteraceae, is one of the major oilseed crops around the world. Charcoal rot caused by Macrophomina phaseolina (Tassi) Goid is the most damaging disease of sunflowers globally. Fungicides are mostly used to control charcoal rot; however, these cause environmental pollution and pose adverse effects on the ecosystem. Therefore, ecofriendly management options are inevitable for the management of charcoal rot disease. Plant mineral nutrition, the use of plant growth-promoting rhizobacteria and biochar have recently been manipulated for the management of different plant diseases. However, the interactive effects of all these treatments have rarely been tested on charcoal rot suppression in sunflowers. This study assessed the influence of sulfur (0 and 2.25 mg/kg) combined with farmyard manure biochar (2%), NPK (20:20:20 mg/kg) and three different plant growth-promoting rhizobacteria (PGPR) strains on the charcoal rot suppression growth, yield, biochemistry and physiology of sunflower. The PGPR strains included in the study were Bacillus sp. strain MR-1/2 (regarded as PGPR1), Achromobacter sp. strain FB-14 (regarded as PGPR2) and Planomicrobium sp. strain MSSA-10 (regarded as PGPR3). The charcoal rot infestation was induced by inoculating the soil with M. phaseolina, and the impacts of the different treatments were studied on the disease infestation, growth, yield, biochemistry and physiology of sunflowers under 0 and 2.25-mg/kg S application. The results revealed that farmyard manure biochar and Planomicrobium sp. strain MSSA-10 in combination with 2.25-mg/kg S proved effective for the management of charcoal rot disease through regulating the antioxidant enzymes’ activities and strengthening the immune system of sunflower plants. The studied health markers (total chlorophyll content and carotenoids) and stress markers (total protein content, catalase and peroxidase) were significantly altered by the applied treatments under 0 and 2.25-mg/kg S applications. The findings of the experiment indicated that both farmyard manure biochar and Planomicrobium sp. strain MSSA-10, combined with 2.25-mg/kg S, could be used to enhance the crop yield and manage charcoal rot disease in sunflowers. Farmyard manure biochar and Planomicrobium sp. strain MSSA-10 are an easy-to-apply, cost-effective, ecofriendly and sustainable option for the management of charcoal rot disease in sunflowers.

ACS Style

Muhammad Ijaz; Abdul Sattar; Ahmad Sher; Sami Ul-Allah; Muhammad Mansha; Kashif Khan; Muhammad Shahzad; Abdullah Al-Sadi; Muhammad Arif; Bandar Aljuaid; Ahmed El-Shehawi; Shahid Farooq. Sulfur Application Combined with Planomicrobium sp. Strain MSSA-10 and Farmyard Manure Biochar Helps in the Management of Charcoal Rot Disease in Sunflower (Helianthus annuus L.). Sustainability 2021, 13, 8535 .

AMA Style

Muhammad Ijaz, Abdul Sattar, Ahmad Sher, Sami Ul-Allah, Muhammad Mansha, Kashif Khan, Muhammad Shahzad, Abdullah Al-Sadi, Muhammad Arif, Bandar Aljuaid, Ahmed El-Shehawi, Shahid Farooq. Sulfur Application Combined with Planomicrobium sp. Strain MSSA-10 and Farmyard Manure Biochar Helps in the Management of Charcoal Rot Disease in Sunflower (Helianthus annuus L.). Sustainability. 2021; 13 (15):8535.

Chicago/Turabian Style

Muhammad Ijaz; Abdul Sattar; Ahmad Sher; Sami Ul-Allah; Muhammad Mansha; Kashif Khan; Muhammad Shahzad; Abdullah Al-Sadi; Muhammad Arif; Bandar Aljuaid; Ahmed El-Shehawi; Shahid Farooq. 2021. "Sulfur Application Combined with Planomicrobium sp. Strain MSSA-10 and Farmyard Manure Biochar Helps in the Management of Charcoal Rot Disease in Sunflower (Helianthus annuus L.)." Sustainability 13, no. 15: 8535.

Journal article
Published: 10 June 2021 in Journal of Fungi
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The aim of this study was to assess the ability of Bacillus amyloliquefaciens, to augment plant growth and suppress gray mold and leaf spot in pepper plants. Morphological modifications in fungal pathogen hyphae that expanded toward the PGPR colonies were detected via scanning electron microscope. Furthermore, preliminary screening showed that PGPR could produce various hydrolytic enzymes in its media. Treatments with B. amyloliquefaciens suppressed Botrytis gray mold and Alternaria leaf spot diseases on pepper caused by Botrytis pelargonii and Alternaria alternata, respectively. The PGPR strain modulated plant physio-biochemical processes. The inoculation of pepper with PGPR decreased protein, amino acid, antioxidant, hydrogen peroxide, lipid peroxidation, and abscisic acid levels but increased salicylic acid and sugar levels compared to those of uninoculated plants, indicating a mitigation of the adverse effects of biotic stress. Moreover, gene expression studies confirmed physio-biochemical findings. PGPR inoculation led to increased expression of the CaXTH genes and decreased expression of CaAMP1, CaPR1, CaDEF1, CaWRKY2, CaBI-1, CaASRF1, CaSBP11, and CaBiP genes. Considering its beneficial effects, the inoculation of B. amyloliquefaciens can be proposed as an eco-friendly alternative to synthetic chemical fungicides.

ACS Style

Elham Kazerooni; Sajeewa Maharachchikumbura; Abdullah Al-Sadi; Sang-Mo Kang; Byung-Wook Yun; In-Jung Lee. Biocontrol Potential of Bacillus amyloliquefaciens against Botrytis pelargonii and Alternaria alternata on Capsicum annuum. Journal of Fungi 2021, 7, 472 .

AMA Style

Elham Kazerooni, Sajeewa Maharachchikumbura, Abdullah Al-Sadi, Sang-Mo Kang, Byung-Wook Yun, In-Jung Lee. Biocontrol Potential of Bacillus amyloliquefaciens against Botrytis pelargonii and Alternaria alternata on Capsicum annuum. Journal of Fungi. 2021; 7 (6):472.

Chicago/Turabian Style

Elham Kazerooni; Sajeewa Maharachchikumbura; Abdullah Al-Sadi; Sang-Mo Kang; Byung-Wook Yun; In-Jung Lee. 2021. "Biocontrol Potential of Bacillus amyloliquefaciens against Botrytis pelargonii and Alternaria alternata on Capsicum annuum." Journal of Fungi 7, no. 6: 472.

Short communication
Published: 31 May 2021 in Indian Phytopathology
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Citrus aurantifolia (acid lime) trees exhibiting yellowing, stem pitting and decline symptoms in Oman were found to be infected by Citrus tristeza virus (CTV) (genus; Closterovirus, family; Closteroviridae). The sequence of the 3′ approximately 9.8 Kb genome, encompassing the partial RNA dependent RNA polymerase to P23 genes including the 3′ UTR region was determined. Pairwise nucleotide comparisons revealed that the Oman isolate had the highest nucleotide identity with those from Mexico and Egyptian isolates. Phylogenetic analysis showed that the Oman isolate clustered with the Egyptian isolate and was identified as T36 genotype. Recombination analysis showed the presence of three potential recombination events and the findings of this study are discussed. Further, extensive studies on CTV species mainly in Oman and as a whole in the Arabian Peninsula is needed, especially after investigating the recombinant 3′ CTV genome isolate.

ACS Style

Abdullah M. Al-Sadi; M. S. Shahid; Hanu R. Pappu. Molecular characterization of the 3′ end of Citrus tristeza virus genome from Oman. Indian Phytopathology 2021, 1 -4.

AMA Style

Abdullah M. Al-Sadi, M. S. Shahid, Hanu R. Pappu. Molecular characterization of the 3′ end of Citrus tristeza virus genome from Oman. Indian Phytopathology. 2021; ():1-4.

Chicago/Turabian Style

Abdullah M. Al-Sadi; M. S. Shahid; Hanu R. Pappu. 2021. "Molecular characterization of the 3′ end of Citrus tristeza virus genome from Oman." Indian Phytopathology , no. : 1-4.

Review
Published: 15 March 2021 in Biology
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Phytoplasmas that are associated with fruit crops, vegetables, cereal and oilseed crops, trees, ornamental, and weeds are increasing at an alarming rate in the Middle East. Up to now, fourteen 16Sr groups of phytoplasma have been identified in association with more than 164 plant species in this region. Peanut witches’ broom phytoplasma strains (16SrII) are the prevalent group, especially in the south of Iran and Gulf states, and have been found to be associated with 81 host plant species. In addition, phytoplasmas belonging to the 16SrVI, 16SrIX, and 16SrXII groups have been frequently reported from a wide range of crops. On the other hand, phytoplasmas belonging to 16SrIV, 16SrV, 16SrX, 16SrXI, 16SrXIV, and 16SrXXIX groups have limited geographical distribution and host range. Twenty-two insect vectors have been reported as putative phytoplasma vectors in the Middle East, of which Orosius albicinctus can transmit diverse phytoplasma strains. Almond witches’ broom, tomato big bud, lime witches’ broom, and alfalfa witches’ broom are known as the most destructive diseases. The review summarizes phytoplasma diseases in the Middle East, with specific emphasis on the occurrence, host range, and transmission of the most common phytoplasma groups.

ACS Style

Chamran Hemmati; Mehrnoosh Nikooei; Ali Al-Subhi; Abdullah Al-Sadi. History and Current Status of Phytoplasma Diseases in the Middle East. Biology 2021, 10, 226 .

AMA Style

Chamran Hemmati, Mehrnoosh Nikooei, Ali Al-Subhi, Abdullah Al-Sadi. History and Current Status of Phytoplasma Diseases in the Middle East. Biology. 2021; 10 (3):226.

Chicago/Turabian Style

Chamran Hemmati; Mehrnoosh Nikooei; Ali Al-Subhi; Abdullah Al-Sadi. 2021. "History and Current Status of Phytoplasma Diseases in the Middle East." Biology 10, no. 3: 226.

Mini review
Published: 11 March 2021 in Frontiers in Cellular and Infection Microbiology
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Wheat is among the ten top and most widely grown crops in the world. Several diseases cause losses in wheat production in different parts of the world. Bipolaris sorokiniana (teleomorph, Cochliobolus sativus) is one of the wheat pathogens that can attack all wheat parts, including seeds, roots, shoots, and leaves. Black point, root rot, crown rot and spot blotch are the main diseases caused by B. sorokiniana in wheat. Seed infection by B. sorokiniana can result in black point disease, reducing seed quality and seed germination and is considered a main source of inoculum for diseases such as common root rot and spot blotch. Root rot and crown rot diseases, which result from soil-borne or seed-borne inoculum, can result in yield losses in wheat. Spot blotch disease affects wheat in different parts of the world and cause significant losses in grain yield. This review paper summarizes the latest findings on B. sorokiniana, with a specific emphasis on management using genetic, chemical, cultural, and biological control measures.

ACS Style

Abdullah M. Al-Sadi. Bipolaris sorokiniana-Induced Black Point, Common Root Rot, and Spot Blotch Diseases of Wheat: A Review. Frontiers in Cellular and Infection Microbiology 2021, 11, 1 .

AMA Style

Abdullah M. Al-Sadi. Bipolaris sorokiniana-Induced Black Point, Common Root Rot, and Spot Blotch Diseases of Wheat: A Review. Frontiers in Cellular and Infection Microbiology. 2021; 11 ():1.

Chicago/Turabian Style

Abdullah M. Al-Sadi. 2021. "Bipolaris sorokiniana-Induced Black Point, Common Root Rot, and Spot Blotch Diseases of Wheat: A Review." Frontiers in Cellular and Infection Microbiology 11, no. : 1.

Research article
Published: 01 February 2021 in Plant Disease
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Cacti are evergreen perennial succulent plants that are used as ornamental and hedge plants. The fruits and leaves are also used as forage in some areas (Dewir, 2016). Cactus species are susceptible to several pathogens, including phytoplasma. In March 2020, three cactus plants (Opuntia cylindrica) out of ten (30% incidence) exhibited phytoplasma symptoms, including stunted growth, fasciation in stems and cladodes, color changes of the tips of cladodes to purple, and having clusters of highly proliferating cladodes. The plants were located in the Botanic Garden at Sultan Qaboos University, Muscat, Oman (N:23º59'14"; E:58º16'34"). PCR assays were carried out on the DNA samples extracted from young cladodes of three each of symptomatic and asymptomatic plants using phytoplasma-universal 16S rRNA primers, P1/P7 in direct PCR followed by R16F2n/R16R2, P4/P7 in the nested PCR. Distilled water (DW) and Alfalfa witches’ broom phytoplasma (AlfWB) were used as negative and positive controls in each assay, respectively. In addition, amplification of the partial translocase protein A (secA) gene in the symptomatic cactus samples was done using SecA-II-F1/SecA-II-R1 (targeting 2140 bp) followed by SecA-II-F1/SecAR4 (targeting 1510 bp) (Al-Subhi et al., 2018). All the symptomatic plants and the positive control were positive for both genes (16S and secA), but no amplification was observed from the asymptomatic samples and DW. Sequence analysis and similarity searches against BLASTn revealed that the phytoplasma 16S rRNA (MT327813) shared 100% sequence identity with that of ’Candidatus Phytoplasma aurantifolia’ isolate CB04 (MT555412) from India. The secA gene sequence (MT331815) analysis showed 100% identity with Cicer arietinum phyllody (KX358585). The associated phytoplasma was designated as cactus fasciated phytoplasma (CFP). Phylogenetic trees based on CFP 16Sr rRNA,secA genes, and a combined phylogenetic tree showed clustering of the CFP with the 16SrII-D subgroup phytoplasmas. The association of the aster yellows and peanut witches’-broom phytoplasma groups with other cactus species has already been reported from Lebanon, Mexico, China, Italy and Egypt (Dewir, 2016). The 16SrII phytoplasma in association with O. cylindrica showing fasciated stem has been reported from Egypt (Omar et al., 2014). A series of diverse plant species in association with 16SrII-D phytoplasma has been reported from Oman (Al-Subhi et al., 2018). However, this is the first report of a cactus phytoplasma disease in Oman belonging to the 16SrII-D subgroup phytoplasmas. Some fasciated cactus species are attractive and therefore cultivated as new ornamental plants and transported around the world, which may pose a new threat to other economically important crops.

ACS Style

Chamran Hemmati; Ali Masoud Al-Subhi; Mohammed Al-Housni; Abdullah Mohammed Al-Sadi. First Report of a Subgroup 16SrII-D Phytoplasma Associated with Opuntia cylindrica Fasciated Disease in Oman. Plant Disease 2021, 105, 485 .

AMA Style

Chamran Hemmati, Ali Masoud Al-Subhi, Mohammed Al-Housni, Abdullah Mohammed Al-Sadi. First Report of a Subgroup 16SrII-D Phytoplasma Associated with Opuntia cylindrica Fasciated Disease in Oman. Plant Disease. 2021; 105 (2):485.

Chicago/Turabian Style

Chamran Hemmati; Ali Masoud Al-Subhi; Mohammed Al-Housni; Abdullah Mohammed Al-Sadi. 2021. "First Report of a Subgroup 16SrII-D Phytoplasma Associated with Opuntia cylindrica Fasciated Disease in Oman." Plant Disease 105, no. 2: 485.

Article
Published: 23 January 2021 in Fungal Diversity
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Hot desert regions are undoubtedly challenging to fungal survival on the Arabian Peninsula. Fungi are, however, recognized as the most stress-resistant organisms among all eukaryotes, which could be a result of the rapid evolution of distinct species. Our current understanding of these microorganisms is derived from studies examining only a fraction of the overall fungal diversity. Therefore, further studies are needed to understand the diversity of fungi in desert regions. This paper highlights the taxonomy of several unusual fungal genera collected in a range of aquatic and terrestrial environments in Oman. These taxa were identified based on phylogenetic analyses of nuclear ribosomal DNA (rDNA) (LSU, SSU and ITS) and protein-coding genes (TEF, RPB2 and TUB), plus morphological comparisons. Phylogenetic analyses, including the presently recognized genera in Patellariales resulted in splitting the order into four clades in Dothideomycetes. The new family Holmiellaceae and new order Holmiellales are introduced to include Holmiella. Species of Homortomycetaceae form a well-supported and distinct clade and raise it to Homortomycetales ordo novus. Omania (Halojulellaceae), Desertiserpentica (Lophiostomataceae) and Montanitestudina (Testudinaceae) are described as novel genera in Dothideomycetes. A synnematous hyphomycete with basidiomycetous affinity (Corticiales) was also identified and described as Basidiodesertica. Additionally, an asexual morph was observed for Holmiella junipericola; Patellaria quercus is synonymized under P. atrata, and seven new species are described.

ACS Style

Sajeewa S. N. Maharachchikumbura; Dhanushka N. Wanasinghe; Ratchadawan Cheewangkoon; Abdullah M. Al-Sadi. Uncovering the hidden taxonomic diversity of fungi in Oman. Fungal Diversity 2021, 106, 229 -268.

AMA Style

Sajeewa S. N. Maharachchikumbura, Dhanushka N. Wanasinghe, Ratchadawan Cheewangkoon, Abdullah M. Al-Sadi. Uncovering the hidden taxonomic diversity of fungi in Oman. Fungal Diversity. 2021; 106 (1):229-268.

Chicago/Turabian Style

Sajeewa S. N. Maharachchikumbura; Dhanushka N. Wanasinghe; Ratchadawan Cheewangkoon; Abdullah M. Al-Sadi. 2021. "Uncovering the hidden taxonomic diversity of fungi in Oman." Fungal Diversity 106, no. 1: 229-268.

Research article
Published: 01 January 2021 in Plant Disease
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The African marigold (Tagetes erecta L.) is an ornamental, herbaceous plant commonly found in Oman. In 2019, African marigold plants showing phyllody and virescence symptoms, which are typical symptoms of phytoplasmas disease, were found in at Sultan Qaboos University in Oman. Transmission electron microscopy of marigold leaf midrib from phyllody disease plants showed the presence of numerous phytoplasma bodies in the sieve tube of all of the symptomatic samples. DNA was extracted from asymptomatic and symptomatic marigold plant samples, followed by PCR of the 16S ribosomal RNA (rRNA) and imp genes. The PCR assays showed that the symptomatic plants are positive for phytoplasma. The DNA sequence analysis and phylogenetic trees showed that the 16S rDNA and imp gene sequences from all marigold phyllody strains shared 100% sequence identity to 16SrII-D subgroup sequences in the GenBank. This is the first report of a phytoplasma of the 16SrII-D subgroup associated with the African marigold (T. erecta) worldwide.

ACS Style

Ali Masoud Al-Subhi; Rashid A. Al-Yahyai; Abdullah Mohammed Al-Sadi. Association of the 16SrII-D Phytoplasma with African Marigold (Tagetes erecta) Phyllody in Oman. Plant Disease 2021, 105, 27 -30.

AMA Style

Ali Masoud Al-Subhi, Rashid A. Al-Yahyai, Abdullah Mohammed Al-Sadi. Association of the 16SrII-D Phytoplasma with African Marigold (Tagetes erecta) Phyllody in Oman. Plant Disease. 2021; 105 (1):27-30.

Chicago/Turabian Style

Ali Masoud Al-Subhi; Rashid A. Al-Yahyai; Abdullah Mohammed Al-Sadi. 2021. "Association of the 16SrII-D Phytoplasma with African Marigold (Tagetes erecta) Phyllody in Oman." Plant Disease 105, no. 1: 27-30.

Agriculture
Published: 28 December 2020 in All Life
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The biocontrol potential of antagonistic bacteria and yeasts isolated from tomato phyllosphere and fructoplane was evaluated against fruit rot of tomato caused by Alternaria alternata. A total of 48 bacterial and 24 yeast isolates were obtained from field-grown tomato leaves/fruits collected from Barka, Oman. The antagonistic activities of these isolates were evaluated against A. alternata using in vitro dual culture assay. Among the 72 bacterial and yeast isolates tested, one yeast (Meyerozyma guilliermondii) and two bacteria (Enterobacter roggenkampii and Pseudomonas aeruginosa) showed inhibitory activity against A. alternata. Examination of hyphal morphology of A. alternata at the edge of inhibition zone using scanning electron microscopy revealed abnormalities such as twisting, shriveling, distortion and collapsing of hyphae. Postharvest treatment of tomato fruits with E. roggenkampii, P. aeruginosa and M. guilliermondii reduced the fruit rot lesion size by 60%, 57% and 50%, respectively, compared to untreated control. The antifungal metabolites produced by the antagonistic yeast M. guilliermondii were fractionated using thin-layer chromatography. Characterization of the bioactive fractions using gas chromatography-mass spectrometry revealed the presence of different types of alkanes, predominantly tricosane and pentacosane, suggesting that volatile compounds, especially alkanes, produced by M. guilliermondii might also be involved in the suppression of A. alternata.

ACS Style

Samiya Saleh Al-Maawali; Abdullah Mohammed Al-Sadi; Salama Ali Khalifa Alsheriqi; Jamal Nasser Al-Sabahi; Rethinasamy Velazhahan. The potential of antagonistic yeasts and bacteria from tomato phyllosphere and fructoplane in the control of Alternaria fruit rot of tomato. All Life 2020, 14, 34 -48.

AMA Style

Samiya Saleh Al-Maawali, Abdullah Mohammed Al-Sadi, Salama Ali Khalifa Alsheriqi, Jamal Nasser Al-Sabahi, Rethinasamy Velazhahan. The potential of antagonistic yeasts and bacteria from tomato phyllosphere and fructoplane in the control of Alternaria fruit rot of tomato. All Life. 2020; 14 (1):34-48.

Chicago/Turabian Style

Samiya Saleh Al-Maawali; Abdullah Mohammed Al-Sadi; Salama Ali Khalifa Alsheriqi; Jamal Nasser Al-Sabahi; Rethinasamy Velazhahan. 2020. "The potential of antagonistic yeasts and bacteria from tomato phyllosphere and fructoplane in the control of Alternaria fruit rot of tomato." All Life 14, no. 1: 34-48.

Research article
Published: 21 December 2020 in Plant Disease
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An insect-transmitted phytoplasma causing Witches’ Broom Disease of Lime (WBDL) is responsible for the drastic decline in lime production in several countries. However, it is unclear how WBDL phytoplasma (WBDLp) induces witches’ broom symptoms and if these symptoms contribute to the spread of phytoplasma. Here we show that the gene encoding SAP11 of WBDLp (SAP11WBDL) is present in all WBDLp isolates collected from diseased trees. SAP11WBDL interacts with acid lime (Citrus aurantifolia) TCP transcription factors, specifically members of the TB1/CYC class that have a role in suppressing axillary branching in plants. Sampling of WBDLp-infected lime trees revealed that WBDLp titers and SAP11WBDL expression levels were higher in symptomatic leaves compared to asymptomatic sections of the same trees. Moreover, the witches’ brooms were found to attract the vector leafhopper. Defense genes that have a role in plant defense responses to bacteria and insects are more downregulated in witches’ brooms compared to asymptomatic sections of trees. These findings suggest that witches’ broom-affected parts of the trees contribute to WBDL epidemics by supporting higher phytoplasma titers and attracting insect vectors.

ACS Style

Ali Masoud Al-Subhi; Abdullah Mohammed Al-Sadi; Rashid Al-Yahyai; Yazhou Chen; Thomas Mathers; Zigmunds Orlovskis; Gabriele Moro; Sam Mugford; Khalid Al-Hashmi; Saskia Hogenhout. Witches’ broom disease of lime contributes to phytoplasma epidemics and attracts insect vectors. Plant Disease 2020, 1 .

AMA Style

Ali Masoud Al-Subhi, Abdullah Mohammed Al-Sadi, Rashid Al-Yahyai, Yazhou Chen, Thomas Mathers, Zigmunds Orlovskis, Gabriele Moro, Sam Mugford, Khalid Al-Hashmi, Saskia Hogenhout. Witches’ broom disease of lime contributes to phytoplasma epidemics and attracts insect vectors. Plant Disease. 2020; ():1.

Chicago/Turabian Style

Ali Masoud Al-Subhi; Abdullah Mohammed Al-Sadi; Rashid Al-Yahyai; Yazhou Chen; Thomas Mathers; Zigmunds Orlovskis; Gabriele Moro; Sam Mugford; Khalid Al-Hashmi; Saskia Hogenhout. 2020. "Witches’ broom disease of lime contributes to phytoplasma epidemics and attracts insect vectors." Plant Disease , no. : 1.

Research article
Published: 01 December 2020 in Plant Disease
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Cycas revoluta Thunb. (Cycadaceae) is native to southern Japan and used for production of Sago and is planted as an ornamental plant. In Oman, it is mainly used for ornamental purposes. In February 2020, typical symptoms of a phytoplasma disease were observed and symptoms included yellowing, dryness and abnormality of leaves with elongated internodes and malformed leaflets, with numerous, small leaves emerging from the trunks of plants at Sultan Qaboos University (SQU) campus, Muscat, Oman (N: 3º59'14"; E: 58º16'34"). The disease affected 4 (10%) out of approximately 40 trees grown on campus. Four symptomatic and two asymptomatic Cycas leaf samples were collected, and the total genomic DNA was isolated using CTAB method with some modification (Doyle 1991). A nested-PCR assay was used to amplify the 16S rRNA region of the associated phytoplasma using the primer pairs P1/P7 (Gunderson and Lee 1996) and R16F2n/R16R2 (Smart et al. 1996). Sterile distilled water (DW) and Alfalfa witches’ broom phytoplasma were used as negative and positive controls, respectively. All symptomatic plants and positive control produced an expected amplicon size of ≈1800 bp and 1250 bp and no such amplicons were detected in the negative control. The obtained fragments were sequenced bidirectionally, assembled and our four sequences of 1636 bp (accession numbers MT239343, MT239344, MT239345 and MT239346) showed 100% homology with alfalfa phytoplasma isolate from Sudan (KY449416). The presence of phytoplasma was further confirmed by amplifying the tuf gene using TUF-II-F1/TUF-II-R1 followed by semi-nested PCR (Al-Subhi et al., 2018). Two sequences were submitted to GenBank under accession numbers MT254086 and MT254087. The constructed phylogenetic tree of combined sequences of 16S rRNA and tuf genes showed clustering of the phytoplasma from the present study with phytoplasmas in 16SrII-D subgroup. The associated phytoplasma was designated as Cycas yellowing phytoplasma (CYP). Phytoplasma strains of 16SrII-D phytoplasmas are known to be associated with several economic important plants as well as weeds in Oman (Al-Subhi et al. 2018). Associations of phytoplasmas and C. revoluta have been previously reported in India and Egypt (Behiry 2018; Kumar et al. 2012). The present study is the first report of association of a 16SrII-D subgroup phytoplasma with Cycas yellowing in Oman. Given that the symptoms affect the aesthetics of Cycas species in gardens, there is a need to develop management practices to prevent the spread of the pathogen.

ACS Style

Chamran Hemmati; Ali Masoud Al-Subhi; Abdullah Mohammed Al-Sadi. First Report of Association of 16SrII-D Phytoplasma with Cycas revoluta in Oman. Plant Disease 2020, 104, 3249 -3249.

AMA Style

Chamran Hemmati, Ali Masoud Al-Subhi, Abdullah Mohammed Al-Sadi. First Report of Association of 16SrII-D Phytoplasma with Cycas revoluta in Oman. Plant Disease. 2020; 104 (12):3249-3249.

Chicago/Turabian Style

Chamran Hemmati; Ali Masoud Al-Subhi; Abdullah Mohammed Al-Sadi. 2020. "First Report of Association of 16SrII-D Phytoplasma with Cycas revoluta in Oman." Plant Disease 104, no. 12: 3249-3249.

Research article
Published: 21 November 2020 in Biocontrol Science and Technology
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Cladosporium omanense has been recently described as a novel endophytic fungus from Zygophyllum coccineum in the desert habitat of Oman. The ability of this fungus to suppress Pythium aphanidermatum, the cause of cucumber and radish damping-off disease, was investigated. In vitro results showed effective suppression of P. aphanidermatum by C. omanense, producing an inhibition zone of 3.67 mm in dual culture assay. Light microscope and scanning electron microscope examination showed abnormalities in Pythium hyphae at the inhibition zone. The culture filtrate from C. omanense induced cellular leakage from Pythium mycelium and inhibited oospore production. A bioassay test was further conducted to examine the ability of C. omanense in suppressing P. aphanidermatum-induced damping-off disease of cucumber. It showed that C. omanense significantly increased the percent surviving cucumber seedlings up to 58.9%. Similarly, the addition of C. omanense significantly increased the percent surviving radish seedlings up to 80.4%. The in vivo and in vitro suppression effects of C. omanense were mainly due to the production of cellulase, β-1,3-glucanases and siderophores in the culture filtrate of C. omanense. This is the first report describing the biocontrol efficacy of C. omanense, especially in suppressing P. aphanidermatum-induced damping-off of cucumber and radish.

ACS Style

Boshra A. Halo; Rashid A. Al-Yahyai; Abdullah M. Al-Sadi. Biological control of Pythium aphanidermatum-induced cucumber and radish damping-off by an endophytic fungus, Cladosporium omanense isolate 31R. Biocontrol Science and Technology 2020, 31, 235 -251.

AMA Style

Boshra A. Halo, Rashid A. Al-Yahyai, Abdullah M. Al-Sadi. Biological control of Pythium aphanidermatum-induced cucumber and radish damping-off by an endophytic fungus, Cladosporium omanense isolate 31R. Biocontrol Science and Technology. 2020; 31 (3):235-251.

Chicago/Turabian Style

Boshra A. Halo; Rashid A. Al-Yahyai; Abdullah M. Al-Sadi. 2020. "Biological control of Pythium aphanidermatum-induced cucumber and radish damping-off by an endophytic fungus, Cladosporium omanense isolate 31R." Biocontrol Science and Technology 31, no. 3: 235-251.

Review
Published: 18 November 2020 in Sustainability
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Sufficient production, consistent food supply, and environmental protection in urban +settings are major global concerns for future sustainable cities. Currently, sustainable food supply is under intense pressure due to exponential population growth, expanding urban dwellings, climate change, and limited natural resources. The recent novel coronavirus 2019 (COVID-19) pandemic crisis has impacted sustainable fresh food supply, and has disrupted the food supply chain and prices significantly. Under these circumstances, urban horticulture and crop cultivation have emerged as potential ways to expand to new locations through urban green infrastructure. Therefore, the objective of this study is to review the salient features of contemporary urban horticulture, in addition to illustrating traditional and innovative developments occurring in urban environments. Current urban cropping systems, such as home gardening, community gardens, edible landscape, and indoor planting systems, can be enhanced with new techniques, such as vertical gardening, hydroponics, aeroponics, aquaponics, and rooftop gardening. These modern techniques are ecofriendly, energy- saving, and promise food security through steady supplies of fresh fruits and vegetables to urban neighborhoods. There is a need, in this modern era, to integrate information technology tools in urban horticulture, which could help in maintaining consistent food supply during (and after) a pandemic, as well as make agriculture more sustainable.

ACS Style

Muhammad Khan; Muhammad Akram; Rhonda Janke; Rashad Qadri; Abdullah Al-Sadi; Aitazaz Farooque. Urban Horticulture for Food Secure Cities through and beyond COVID-19. Sustainability 2020, 12, 9592 .

AMA Style

Muhammad Khan, Muhammad Akram, Rhonda Janke, Rashad Qadri, Abdullah Al-Sadi, Aitazaz Farooque. Urban Horticulture for Food Secure Cities through and beyond COVID-19. Sustainability. 2020; 12 (22):9592.

Chicago/Turabian Style

Muhammad Khan; Muhammad Akram; Rhonda Janke; Rashad Qadri; Abdullah Al-Sadi; Aitazaz Farooque. 2020. "Urban Horticulture for Food Secure Cities through and beyond COVID-19." Sustainability 12, no. 22: 9592.

Proceedings
Published: 13 November 2020 in Chemistry Proceedings
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The design and synthesis of new, safe and potent molecules to apply against soil-borne pathogens is a critical goal for organic and bio-medicinal chemists. Herein, we designed and synthesized a series of benzimidazole-based carbamate derivatives (7a–f), as soil-borne anti-fungals. The derivatives 7a–f were all synthesized in multi-step reactions with acceptable yields. The structures of 7a–f were all identified and characterized using 1H-NMR, IR, HRMS, and melting point calculations. The final compounds were tested on five soil-borne pathogens. The results of various bio-assays showed that compounds 7a-3, 7a-2, 7b-2, 7a-1 and 7b-1 significantly affected the growth of Pythium aphanidermatum, a serious pathogen affecting vegetable crops worldwide. Compounds 7a-1 and 7b-1 were the most efficacious, which resulted in a 96% growth inhibition in Pythium at 100 mg L−1. In conclusion, we reported the potent carbamate derivatives as soil-borne anti-fungals, and believe that the synthesis of more derivatives related to the current scaffold would be beneficial.

ACS Style

Thuraya Al–Harthy; Abdullah M. Al-Sadi; Wajdi Zoghaib; Ebrahim Moghadam; Raphael Stoll; Raid Abdel-Jalil. Design, Synthesis and Bioactivity of Benzimidazole–2–Carbamates as Soil–Borne Anti–Fungal Agents †,‡. Chemistry Proceedings 2020, 3, 64 .

AMA Style

Thuraya Al–Harthy, Abdullah M. Al-Sadi, Wajdi Zoghaib, Ebrahim Moghadam, Raphael Stoll, Raid Abdel-Jalil. Design, Synthesis and Bioactivity of Benzimidazole–2–Carbamates as Soil–Borne Anti–Fungal Agents †,‡. Chemistry Proceedings. 2020; 3 (1):64.

Chicago/Turabian Style

Thuraya Al–Harthy; Abdullah M. Al-Sadi; Wajdi Zoghaib; Ebrahim Moghadam; Raphael Stoll; Raid Abdel-Jalil. 2020. "Design, Synthesis and Bioactivity of Benzimidazole–2–Carbamates as Soil–Borne Anti–Fungal Agents †,‡." Chemistry Proceedings 3, no. 1: 64.

Journal article
Published: 12 November 2020 in Canadian Journal of Plant Pathology
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Florida or Cuban royal palm (Roystonea regia (Kunth) O.F. Cook) is an important ornamental plant with many uses for humans. Royal palm trees grown in Muscat, Oman, were found exhibiting leaf yellowing, leaf decay starting on the mature leaves, and leaf stunting. Trunk tissue samples were collected and analysed with nested and semi-nested PCR assays for the 16S rRNA, translation elongation factor Tu (tuf), and immunodominant membrane protein (imp) genes, in order to characterize the phytoplasma associated with the affected trees. Sequence and phylogenetic analysis of the 16S rRNA, tuf, and imp genes indicated that the phytoplasma strains detected in the trees were identical and belonged to the 16SrII-D subgroup. This is the first report of an association between ‘Candidatus Phytoplasma asutralasia’-related strain and R. regia.

ACS Style

Chamran Hemmati; Ali Masood Al-Subhi; Abdullah Mohammed Al-Sadi. Multigene characterization of a ‘Candidatus Phytoplasma australasia’ strain associated with Roystonea regia in Oman. Canadian Journal of Plant Pathology 2020, 43, 374 -383.

AMA Style

Chamran Hemmati, Ali Masood Al-Subhi, Abdullah Mohammed Al-Sadi. Multigene characterization of a ‘Candidatus Phytoplasma australasia’ strain associated with Roystonea regia in Oman. Canadian Journal of Plant Pathology. 2020; 43 (3):374-383.

Chicago/Turabian Style

Chamran Hemmati; Ali Masood Al-Subhi; Abdullah Mohammed Al-Sadi. 2020. "Multigene characterization of a ‘Candidatus Phytoplasma australasia’ strain associated with Roystonea regia in Oman." Canadian Journal of Plant Pathology 43, no. 3: 374-383.

Article
Published: 09 September 2020 in Australasian Plant Disease Notes
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Date palm is the most important fruit crop in Oman, covering about 50% of the agricultural area in the country. During a survey in 2018–2020, symptoms resembling phytoplasma diseases were observed in date palms in Muscat, Oman. Date palms showed streak yellows and dryness of young and mature leaflets and leaves. Polymerase chain reaction (PCR) assays were conducted using the universal primer pairs P1/P7 followed by R16F2n/R16r2n. In addition, the phytoplasma genes imp, secA, and tuf were also targeted in semi-nested PCR assays by using specific primers for each gene. Symptomatic trees were positive for phytoplasma presence in nested and semi-direct PCR, however, no amplification was observed from the symptomless and negative control. Sequence analysis of the rRNA, imp, secA, and tuf genes confirmed that the phytoplasma associated with streak yellow date palm (SYDP) is a strain of the 16SrII-D subgroup. This is the first record of association of a phytoplasmas of the 16SrII-D subgroup with date palms in Oman. This finding increased our knowledge about the distribution of phytoplasma diseases in date palms in the world.

ACS Style

Chamran Hemmati; Ali M. Al-Subhi; Mohammed T. Al-Housni; Abdullah M. Al-Sadi. Molecular detection and characterization of a 16SrII-D phytoplasma associated with streak yellows of date palm in Oman. Australasian Plant Disease Notes 2020, 15, 1 -4.

AMA Style

Chamran Hemmati, Ali M. Al-Subhi, Mohammed T. Al-Housni, Abdullah M. Al-Sadi. Molecular detection and characterization of a 16SrII-D phytoplasma associated with streak yellows of date palm in Oman. Australasian Plant Disease Notes. 2020; 15 (1):1-4.

Chicago/Turabian Style

Chamran Hemmati; Ali M. Al-Subhi; Mohammed T. Al-Housni; Abdullah M. Al-Sadi. 2020. "Molecular detection and characterization of a 16SrII-D phytoplasma associated with streak yellows of date palm in Oman." Australasian Plant Disease Notes 15, no. 1: 1-4.

Journal article
Published: 31 July 2020 in Canadian Journal of Plant Pathology
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ACS Style

Ali M. Al-Subhi; Saskia Hogenhout; Rashid Abdullah Al-Yahyai; Aisha Gharib Al-Ghaithi; Abdullah Mohammed Al-Sadi. Evaluating the effect of tuf and secA gene sequence length for discrimination of phytoplasmas. Canadian Journal of Plant Pathology 2020, 43, 209 -215.

AMA Style

Ali M. Al-Subhi, Saskia Hogenhout, Rashid Abdullah Al-Yahyai, Aisha Gharib Al-Ghaithi, Abdullah Mohammed Al-Sadi. Evaluating the effect of tuf and secA gene sequence length for discrimination of phytoplasmas. Canadian Journal of Plant Pathology. 2020; 43 (2):209-215.

Chicago/Turabian Style

Ali M. Al-Subhi; Saskia Hogenhout; Rashid Abdullah Al-Yahyai; Aisha Gharib Al-Ghaithi; Abdullah Mohammed Al-Sadi. 2020. "Evaluating the effect of tuf and secA gene sequence length for discrimination of phytoplasmas." Canadian Journal of Plant Pathology 43, no. 2: 209-215.

Research article
Published: 28 June 2020 in Plant Disease
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Squash leaf curl virus (SLCV) is a New World (NW) bipartite begomovirus (genus Begomovirus, family Geminiviridae), native to Central and southern North America. It was first detected in California in 1970’s and was reported for the first time in Middle East in Israel (Anignus et al., 2003), although the mechanism of introduction in this case remained unclear. In 2016, a survey was conducted to figure out the extent and distribution of begomoviruses spreading in the Sultanate of Oman. Thirty eight leaf samples from different plant species were collected from five geographically diverse regions, including four leaf samples from squash plants that exhibited severe curling, yellowing and stunting, typical of bipartite begomovirus infection, in two distinct and open field farms in the Al-Barka (coordinates 23° 42' 26.69" N 57° 53' 20.78" E) region, Oman. High to medium vector (whitefly: Bemisia tabaci) population followed by disease incidence (35-55%) was observed in the squash fields. By electron microscopy, geminiviruses particles of twinned-icosahedral (18-20 nm) structure were observed in crude sap of infected leaves. Suspecting infection by SLCV, genomic DNA was extracted using CTAB method (Porebski et al. 1997) from infected and healthy leaf samples and used as templates in polymerase chain reaction (PCR) using bipartite begomovirus detection primers (Rojas et al. 1993). All the four symptomatic samples showed positive reaction in PCR and the amplified PCR amplicons for DNA A (1.1 kb) and DNA B (0.5 kb) were cloned in PTZ57R/T (Thermo Scientific, USA) and sequenced commercially (Macrogen, South Korea). The BLAST analysis of both the genomic components revealed that the nucleotide (nt.) sequence identity had more than 99% with squash leaf curl virus isolate from Oman (GenBank HG969277 and HG941652, respectively). In order to obtain full-length viral genome, two representative samples (Sq-16/21) were selected for rolling circle amplification (RCA) method using an Illustra TempliPhi amplification kit (GE Healthcare). RCA products were digested with multiple restriction endonucleases to obtain ~ 2.7 kb linear DNA fragments. Approximately 2.7 kb linear molecules produced by BamHI and Pst1 digestion were cloned into pUC19 plasmid vector linearized by BamHI and PstI, respectively. Multiple clones having the similar restriction fragment length polymorphism (RFLP) pattern were obtained, and a single clone from each amplification (Sq-5A and Sq-9B respectively) was selected and sequenced entirely. Efforts to detect DNA satellites (alphasatellite/betasatellite) either in PCR using specific primers (Bull et al. 2003; Shahid et al. 2017) or in endonuclease restriction of RCA products were unsuccessful. Pairwise multiple sequence alignments analysis by Sequence Demarcation Tool (SDT) (Muhire et al. 2014) revealed that the complete DNA-A of Sq-5A (2,637 nt; GenBank Acc. No. MT032114) exhibited the highest identity (99.6%) with an unpublished DNA-A sequence of SLCV (HG969277) from Oman and the DNA B of Sq-9B (2,608 nt; GenBank Acc. No. MT032114) exhibited the highest identity (99.7%) with a SLCV isolate (HG941652) from squash in Oman. followed by 98% with an SLCV isolate from Israel (IsSq-C2; KT099165 (Rosario et al. 2015). To the best of our knowledge this is the first report of a NW bipartite begomovirus (SLCV) infecting squash in Oman. Many monopartite begomoviruses have been reported to infect different vegetable crops in Oman and the addition of a bipartite begomovirus may pose potentially a serious threat through mixed infections to cucurbits crops in Oman.

ACS Style

Muhammad Shafiq Shahid; Hamed Al-Sulaimani; Abdullah Mohammed Al-Sadi. Squash Leaf Curl Virus: A New World Bipartite Begomovirus Threatening Squash Production in Oman. Plant Disease 2020, 1 -02.

AMA Style

Muhammad Shafiq Shahid, Hamed Al-Sulaimani, Abdullah Mohammed Al-Sadi. Squash Leaf Curl Virus: A New World Bipartite Begomovirus Threatening Squash Production in Oman. Plant Disease. 2020; ():1-02.

Chicago/Turabian Style

Muhammad Shafiq Shahid; Hamed Al-Sulaimani; Abdullah Mohammed Al-Sadi. 2020. "Squash Leaf Curl Virus: A New World Bipartite Begomovirus Threatening Squash Production in Oman." Plant Disease , no. : 1-02.

Journal article
Published: 18 June 2020 in Phytotaxa
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Bimuria is a monotypic genus in Didymosphaeriaceae, typified by B. novae-zelandiae collected in terrestrial habitats from New Zealand soil. In our study, Bimuria omanensis, a novel species was isolated from unidentified decaying leaves in Oman. The phylogenetic placement of B. omanensis is resolved based on maximum likelihood, maximum parsimony and Bayesian analyses of combined LSU, ITS and TEF1-α sequence data of Didymosphaeriaceae. The placement of Bimuria omanensis as a distinct species, is confirmed based on phylogeny. This is the first record of an asexual morph in Bimuria and first record of a Bimuria species from Oman. The relationship of this taxon with other phylogenetically closely related Didymosphaeriaceae species is shown.

ACS Style

Nuwanthika Wijesinghe; Dhanushka N. Wanasinghe; Sajeewa S. N. Maharachchikumbura; Yong Wang; Abdullah M. Al-Sadi; Kevin D. Hyde. Bimuria omanensis sp. nov. (Didymosphaeriaceae, Pleosporales) from Oman. Phytotaxa 2020, 449, 97 -108.

AMA Style

Nuwanthika Wijesinghe, Dhanushka N. Wanasinghe, Sajeewa S. N. Maharachchikumbura, Yong Wang, Abdullah M. Al-Sadi, Kevin D. Hyde. Bimuria omanensis sp. nov. (Didymosphaeriaceae, Pleosporales) from Oman. Phytotaxa. 2020; 449 (2):97-108.

Chicago/Turabian Style

Nuwanthika Wijesinghe; Dhanushka N. Wanasinghe; Sajeewa S. N. Maharachchikumbura; Yong Wang; Abdullah M. Al-Sadi; Kevin D. Hyde. 2020. "Bimuria omanensis sp. nov. (Didymosphaeriaceae, Pleosporales) from Oman." Phytotaxa 449, no. 2: 97-108.

Review articles
Published: 16 June 2020 in Critical Reviews in Biotechnology
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To fight against pathogens, defense systems in plants mainly depend upon preformed as well as induced responses. Pathogen detection activates induced responses and signals are transmitted for coordinated cellular events in order to restrict infection and spread. In spite of significant developments in manipulating genes, transcription factors and proteins for their involvement in immunity, absolute tolerance/resistance to pathogens has not been seen in plants/crops. Defense responses, among diverse plant types, to different pathogens involve modifications at the physio-biochemical and molecular levels. Secreted by oomycetes, elicitins are small, highly conserved and sterol-binding extracellular proteins with PAMP (pathogen associated molecular patterns) functions and are capable of eliciting plant defense reactions. Belonging to multigene families in oomycetes, elicitins are different from other plant proteins and show a different affinity for binding sterols and other lipids. These function for sterols binding to catalyze their inter-membrane and intra- as well as inter-micelle transport. Importantly, elicitins protect plants by inducing HR (hypersensitive response) and systemic acquired resistance. Despite immense metabolic significance and the involvement in defense activities, elicitins have not yet been fully studied and many questions regarding their functional activities remain to be explained. In order to address multiple questions associated with the role of elicitins, we have reviewed the understanding and topical advancements in plant defense mechanisms with a particular interest in elicitin-based defense actions and metabolic activities. This article offers potential attributes of elicitins as the biological control of plant diseases and can be considered as a baseline toward a more profound understanding of elicitins.

ACS Style

Ali Noman; Muhammad Aqeel; Muhammad Kashif Irshad; Sameer H. Qari; Mohamed Hashem; Saad Alamri; Awatif M. Abdulmajeed; Abdullah M. Al-Sadi. Elicitins as molecular weapons against pathogens: consolidated biotechnological strategy for enhancing plant growth. Critical Reviews in Biotechnology 2020, 40, 821 -832.

AMA Style

Ali Noman, Muhammad Aqeel, Muhammad Kashif Irshad, Sameer H. Qari, Mohamed Hashem, Saad Alamri, Awatif M. Abdulmajeed, Abdullah M. Al-Sadi. Elicitins as molecular weapons against pathogens: consolidated biotechnological strategy for enhancing plant growth. Critical Reviews in Biotechnology. 2020; 40 (6):821-832.

Chicago/Turabian Style

Ali Noman; Muhammad Aqeel; Muhammad Kashif Irshad; Sameer H. Qari; Mohamed Hashem; Saad Alamri; Awatif M. Abdulmajeed; Abdullah M. Al-Sadi. 2020. "Elicitins as molecular weapons against pathogens: consolidated biotechnological strategy for enhancing plant growth." Critical Reviews in Biotechnology 40, no. 6: 821-832.