Publications by authors named "Abdelfattah A Dababat"

21 Publications

  • Page 1 of 1

First Report of Crown Rot Caused by Fusarium redolens on Wheat in Kazakhstan.

Plant Dis 2021 Mar 29. Epub 2021 Mar 29.

CIMMYT Turkey, CIMMYT Uluslararası Buğday ve Mısır Geliştirme Merkezi, Şehit Cem Ersever Caddesi No : 9/11, Tarla Bitkileri Araştırma Enstitüsü Kampüsü içi, Ankara, Ankara, Turkey, 06170;

Fusarium crown rot, caused by several species within the genus, is a major constraint that results in significant losses in wheat production worldwide. In June 2019, diseased wheat plants with typical symptoms of crown rot, including discoloration on the first two or three internodes of the stem just above the soil line and stunted, dry rotted, and discolored roots were collected in several bread wheat fields during the maturity stage in Almaty, East Kazakhstan, and Karaganda Regions of Kazakhstan. For each field, approximately twenty tillers were randomly sampled. Symptomatic tissues were surface sterilized in 1% NaClO for 2 min, rinsed with sterile distilled water three times, air-dried in a laminar flow hood, and then transferred to Petri dishes containing one-fifth strength potato dextrose agar (PDA). After incubating in the dark at 23°C for 5 days, 79 single-spore isolates showing cultural and microscopic characteristics of Fusarium were obtained on PDA and Spezieller-Nährstoffarmer agar (SNA). Colonies were initially white but later produced a beige to pink diffusible pigment in PDA. Microconidia that formed on aerial monophialides were hyaline, 0 to 1 septum, oval- to kidney-shaped, and measured 4.3 to 10.3 × 1.9 to 3.4 µm (average 7.8 × 2.6 µm), whilst macroconidia were straight to slightly curved, 3 to 5 septate, and measured 18.7 to 38.8 × 2.9 to 6.6 µm (average 29.9 × 4.7 µm), with foot-shaped basal cells on SNA. Chlamydospores were present on PDA. Sequence analysis based on portions of translation elongation factor 1α (TEF1) and the nuclear ribosomal internal transcribed spacer region (ITS rDNA) loci with primers EF1/EF2 (O'Donnell et al. 1998) and ITS1/ITS4 (White et al. 1990) identified 29 of the 79 isolates as Fusarium redolens Wollenw. The sequences of the five representative isolates with 99.85% of similarity to those of F. redolens strains available in GenBank e.g., ITS (MT435063) and TEF1 (GU250584). The TEF1 (accession nos. MW403914-MW403918) and ITS rDNA (accession nos. MW397138-MW397142) sequences of the isolates were deposited in GenBank. The morphological features are consistent with the described features of F. redolens (Leslie and Summerell 2006). To confirm pathogenicity of the five isolates, five pre-germinated seeds of wheat cultivar Seri 82 were placed in a 9-cm-diameter pot filled with a sterile potting mix containing equal volumes of peat, vermiculite, and soil. An approximately 1-cm-diameter 7-day-old mycelial plug of each isolate was individually placed in contact with the seeds. Seeds were covered with the same potting mix, and then the pots were maintained for four weeks in a growth chamber at 23°C with a 12-h photoperiod. The experiment was conducted twice with three replicate 15-cm pots with 5 plants per pot. Controls were inoculated with sterile agar plugs using the same procedure. After four weeks, all the inoculated plants showed stunted growth with brown discoloration in most parts of the crown and roots, whereas no symptoms were observed in the control plants. The mean severity of the disease for each isolate was between 2.1 and 2.7 according to the scale of 1 to 5 described by Gebremariam et al. (2015). The pathogen was reisolated from crowns of diseased plants, but not from asymptomatic control tissues, and identified morphologically based on the methods described above, fulfilling Koch's postulates. Although several morphological features are shared by F. oxysporum and F. redolens, Baayen et al. (2001) showed that these species could be easily distinguished using molecular data. The pathogen was previously reported as F. redolens associated with crown rot of wheat in Turkey (Gebremariam et al. 2015) and Saskatchewan, Canada (Taheri et al. 2011). The presence of F. redolens causing crown rot is confirmed in the six wheat fields surveyed in Kazakhstan, for the first time. This pathogen may pose a risk for wheat production, and further studies needed to determine the impact on the crop in Kazakhstan.
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http://dx.doi.org/10.1094/PDIS-01-21-0015-PDNDOI Listing
March 2021

Plant-parasitic nematode associated with wheat in central, eastern, and south-eastern Kazakhstan.

Plant Dis 2021 Mar 23. Epub 2021 Mar 23.

CIMMYT Turkey, CIMMYT Uluslararası Buğday ve Mısır Geliştirme Merkezi, Şehit Cem Ersever Caddesi No : 9/11, Tarla Bitkileri Araştırma Enstitüsü Kampüsü içi, Ankara, Ankara, Turkey, 06170;

Kazakhstan is one of the biggest wheat producers, however, its wheat production is far below the average international wheat production standard due to biotic and abiotic stressors. Plant-parasitic nematodes are devastating for cereal production systems worldwide. A comprehensive survey was conducted in 2019 to identify plant-parasitic nematodes associated with wheat in different locations of central, eastern, and south-eastern Kazakhstan. The results revealed 33 root-lesion and 27 cyst nematode populations from the 77 localities sampled. These two genera occurred in separate or in mixed populations. The root-lesion populations were identified as Pratylenchus neglectus and P. thornei while all cyst nematodes were identified as Heterodera filipjevi. The identification of nematodes was firstly performed based on morphological and morphometric features and confirmed by BLAST and phylogenetic analyses based on the internal transcribed spacer and the D2-D3 expansion located in the 28S gene of ribosomal DNA for CCN and RLN populations, respectively. Pratylenchus neglectus and P. thornei populations from Kazakhstan showed a high similarity with the American, European, and Asian populations. Heterodera filipjevi populations formed a well-supported cluster with the corresponding populations from different countries and showed a slightly intraspecific polymorphism. Kazakhstan populations of H. filipjevi may have multiple introductions in Kazakhstan due to the divergence among them. The results of this study are of great importance for breeding programs and will enable awareness to extension advisors to develop measures to control these nematodes in cereal cropping areas in Kazakhstan.
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http://dx.doi.org/10.1094/PDIS-11-20-2424-SRDOI Listing
March 2021

First Report of Fusarium culmorum and Microdochium bolleyi Causing Root Rot on Triticale in Kazakhstan.

Plant Dis 2021 Mar 3. Epub 2021 Mar 3.

CIMMYT Turkey, CIMMYT Uluslararası Buğday ve Mısır Geliştirme Merkezi, Şehit Cem Ersever Caddesi No : 9/11, Tarla Bitkileri Araştırma Enstitüsü Kampüsü içi, Ankara, Ankara, Turkey, 06170;

Triticale (×Triticosecale Wittmack) is obtained from wheat × rye crossing. It is positioned between wheat and rye in terms of resistance to soilborne pathogens including Gaeumannomyces graminis var. tritici, Fusarium culmorum, F. avenaceum, and Bipolaris sorokiniana (Arseniuk and Góral 2015). In 2019, seven triticale fields were surveyed in Almaty Province, Kazakhstan to examine soil-borne fungal pathogens. A total of 28 symptomatic plants with stunting, rot or discolored root were collected to identify causal agents. The overall disease incidence was approximately 8 to 10% in the fields. Fungi were isolated from 3-5 mm pieces excised from symptomatic tissues. The pieces were exposed to surface disinfection in 1% sodium hypochlorite solution for 2 min, rinsed three times with sterile distilled water, blotted dry, and plated on 1/5 strength potato dextrose agar (PDA) amended with 0.01% streptomycin. Plates were left in the dark at 23°C for 7 days. A total of 34 fungal colonies were isolated of which nineteen isolates, originally from six fields showed the cultural characteristics of B. sorokiniana. This species was previously reported to cause common root rot on triticale in Kazakhstan (Özer et al. 2020). Ten isolates from four fields produced pale orange and cottony mycelium with red pigmentation on the agar, which is typical of Fusarium-like growth. The remaining isolates (n=5) from two fields produced salmon-colored and scarce aerial mycelium with no soluble pigmentation, similar to Microdochium spp. Fusarium isolates produced thick-walled and curved macroconidia with 3-4 septa (n=50, 25.7 to 37.6 × 4.1 to 7.3 μm in size) and notched basal cell on PDA, but microconidia were absent, which matches the description of F. culmorum (Wm.G. Sm.) Sacc. (Leslie and Summerell 2006). Microdochium isolates produced swollen, brown, and thick-walled chlamydospores and hyaline, one-celled, and thin-walled conidia (n=50, 5.4 to 9.3 × 1.5 to 3.0 μm in size) formed on ampullate and cylindrical conidiogenous cells on oatmeal agar (OA). These morphological features are consistent with previous observations for Microdochium bolleyi (R. Sprague) de Hoog & Herm.-Nijh. (Hong et al. 2008). To confirm morphological preliminary identifications, the portion of the translation elongation factor 1-alpha (EF1-α) gene was amplified with EF1/EF2 primers (O'Donnell et al. 1998) for representative Fusarium isolates (n=4) for each field. Additionally, the internal transcribed spacer (ITS) of ribosomal DNA was amplified with ITS1/ITS4 primers (White et al. 1990) for representative Microdochium isolates (n=2) for each field. BLASTn queries against NCBI GenBank revealed that the EF1-α sequences of Fusarium isolates (MW311081-MW311084) shared 100% identity with F. culmorum strain CBS 110262 (KT008433). The ITS sequences of M. bolleyi isolates (MW301448-MW301449) matched that of M. bolleyi strain CBS 137.64 (AM502264) with 100% sequence similarity. Pathogenicity test was conducted on pregerminated seeds of triticale cv. Balausa. A plastic pot (17 cm height, 9 cm in diam) was filled with a sterile mixture of vermiculite, peat, and soil (1:1:1, v/v/v). Mycelial plugs (1 cm in diam) were cut from the margin of a growing culture of representative isolates (Kaz_Fus123 and Kaz_Mb01) and placed onto the mixture in the pot. A sterile agar plug was employed as a control treatment. One pregerminated seed was put on the plug and covered with the mixture. The pots were transferred to a growth chamber set at 23 ± 2°C and a photoperiod of 14 hours. The experiment was performed twice using 5 replication pots per isolate. Four weeks after inoculation, discoloration of the crown was observed on all the inoculated roots, whereas no symptoms were observed on the control plants. Koch's postulates were fulfilled by reisolating and identifying the pathogen based on the morphology described above. This is the first report of M. bolleyi and F. culmorum causing root rot on triticale in Kazakhstan. Although B. sorokiniana is the most primary pathogen that may limit yield in the production of triticale in Kazakhstan, F. culmorum and M. bolleyi have been found to be less frequent and less aggressive pathogens, respectively. Further studies are needed to better understand the potential distribution and impact of these pathogens on triticale.
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http://dx.doi.org/10.1094/PDIS-12-20-2659-PDNDOI Listing
March 2021

Potential of Moroccan entomopathogenic nematodes for the control of the Mediterranean fruit fly Ceratitis capitata Wiedemann (Diptera: Tephritidae).

Sci Rep 2020 11 5;10(1):19204. Epub 2020 Nov 5.

International Maize and Wheat Improvement Center (CIMMYT), P.K. 39, Emek, Ankara, 06511, Turkey.

The Mediterranean fruit fly, Ceratitis capitata Wiedemann, is a deleterious pest worldwide affecting fruit production. The entomopathogenic nematodes (EPNs) are a potential biocontrol agent that could be effectively used to control this Mediterranean fruit fly. In this study, five EPN strains reported from different fields in Morocco were evaluated for their efficacy against C. capitata. In laboratory assays, Steinernema feltiae-SF-MOR9, S. feltiae-SF-MOR10 and Heterorhabditis bacteriophora-HB-MOR7 strains showed significantly higher infectivity and penetration rates when compared to the other strains. S. feltiae-SF-MOR9 caused the highest larval mortality rate (80%) at 50 infective juveniles (IJs) cm. However, additional results showed that both S. feltiae strains were significantly effective in controlling C. capitata larvae in apricot (Prunus armeniaca) fruits on soil surface with high mortality rate at 50 and 100 IJs cm. Different soil textures and moisture levels resulted in a significant variation in EPN strain virulence against C. capitata. Sandy clay loam soil in combination with 50 IJs cm of S. feltiae (SF-MOR9 or SF-MOR10) caused a higher mortality rate of C. capitata larvae. Furthermore, applying these EPN strains at 50-100 IJs cm in combination with 10-15% moisture level showed optimal results against C. capitata larvae. Therefore, those two Moroccan EPN strains could be used as promising eco-friendly biological agents against C. capitata.
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http://dx.doi.org/10.1038/s41598-020-76170-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7645415PMC
November 2020

Reactive oxygen species metabolism and photosynthetic performance in leaves of Hordeum vulgare plants co-infested with Heterodera filipjevi and Aceria tosichella.

Plant Cell Rep 2020 Dec 21;39(12):1719-1741. Epub 2020 Sep 21.

Department of Plant Protection, Section of Applied Entomology, Institute of Horticultural Sciences, Warsaw University of Life Sciences-SGGW, Warsaw, Poland.

Key Message: Defence responses of cyst nematode and/or wheat curl mite infested barley engage the altered reactive oxygen species production, antioxidant machinery, carbon dioxide assimilation and photosynthesis efficiency. The primary aim of this study was to determine how barley responds to two pests infesting separately or at once; thus barley was inoculated with Heterodera filipjevi (Madzhidov) Stelter (cereal cyst nematode; CCN) and Aceria tosichella Keifer (wheat curl mite; WCM). To verify hypothesis about the involvement of redox metabolism and photosynthesis in barley defence responses, biochemical, photosynthesis efficiency and chlorophyll a fluorescence measurements as well as transmission electron microscopy were implemented. Inoculation with WCM (apart from or with CCN) brought about a significant suppression in the efficiency of electron transport outside photosystem II reaction centres. This limitation was an effect of diminished pool of rapidly reducing plastoquinone and decreased total electron carriers. Infestation with WCM (apart from or with CCN) also significantly restricted the electron transport on the photosystem I acceptor side, therefore produced reactive oxygen species oxidized lipids in cells of WCM and double infested plants and proteins in cells of WCM-infested plants. The level of hydrogen peroxide was significantly decreased in double infested plants because of glutathione-ascorbate cycle involvement. The inhibition of nitrosoglutathione reductase promoted the accumulation of S-nitrosoglutathione increasing antioxidant capacity in cells of double infested plants. Moreover, enhanced arginase activity in WCM-infested plants could stimulate synthesis of polyamines participating in plant antioxidant response. Infestation with WCM (apart from or with CCN) significantly reduced the efficiency of carbon dioxide assimilation by barley leaves, whereas infection only with CCN expanded photosynthesis efficiency. These were accompanied with the ultrastructural changes in chloroplasts during CCN and WCM infestation.
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http://dx.doi.org/10.1007/s00299-020-02600-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7502656PMC
December 2020

Efficient antioxidant defence systems of spring barley in response to stress induced jointly by the cyst nematode parasitism and cadmium exposure.

Plant Soil 2020 Sep 14:1-18. Epub 2020 Sep 14.

International Maize and Wheat Improvement Center (CIMMYT), Soil Borne Pathogens Program, Ankara, Turkey.

Aims: This research aimed to establish how responds to abiotic and biotic stress affecting in tandem.

Methods: Plants were inoculated with and treated with cadmium (Cd) concentration (5 μM) that can occur in the cultivated soil. To verify the hypothesis about participation of increased antioxidative defence in under stress, biochemical and microscopic methods were implemented.

Results: The amount of superoxide anions and hydrogen peroxide was diminished in plants that were both nematode-inoculated and cadmium-treated. Superoxide anions were rendered harmless by increased activity of superoxide dismutase, and HO was scavenged via Foyer-Halliwell-Asada pathway. The unique enhanced antioxidant capacity of double stressed plants was also linked with the accumulation of -nitrosoglutathione as nitrosoglutathione reductase activity was inhibited. Furthermore, stimulated activity of arginase in these plants could promote polyamine synthesis and indirectly enhance non-enzymatic antioxidant mechanism. Results indicate that different antioxidants operating together significantly restricted oxidation of lipids and proteins, thus the integrity of cell membranes and protein functions were maintained.

Conclusions: The ROS deactivation machinery in barley leaves showed an unusual response during stress induced by . infection and cadmium treatment. Plants could induce a multi-component model of stress response, to detoxify Cd ions and efficiently repair stress damage.
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http://dx.doi.org/10.1007/s11104-020-04713-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7487286PMC
September 2020

Identity and Pathogenicity of Fungi Associated with Crown and Root Rot of Dryland Winter Wheat in Azerbaijan.

Plant Dis 2020 Aug 26;104(8):2149-2157. Epub 2020 May 26.

International Maize and Wheat Improvement Centre (CIMMYT) P.O. Box. 39 Emek, Ankara, Turkey.

A comprehensive survey was performed to assess fungal populations associated with crown and root rot of wheat throughout the main wheat-growing areas of Azerbaijan. Samples were taken from 76 fields; 630 fungal strains were isolated, identified, and evaluated for pathogenicity. The identification was conducted with morphological and molecular tools such as species-specific PCR and DNA sequencing of the internal transcribed spacer (ITS) and -α (-α) loci. The fungus found in the greatest number of fields (44) was with 192 isolates, followed by . Other spp. isolates were identified: , , , , , , , and . , , , , and spp. isolates were also identified, associated with underground parts of wheat. Phylogenetic analyses based on ITS and -α sequences of the isolates showed that the isolates belonging to the same species were clearly separated in the dendrogram. Pathogenicity assays revealed that , , and were most aggressive; , , , , , and isolates were moderately aggressive; , , and were weakly aggressive; and others were nonpathogenic. The result of this study exhibited the existence of a wide range of species associated with crown and root rot of wheat in Azerbaijan. Additionally, this is the first report of , , , , and as pathogens on wheat in Azerbaijan. Azerbaijan is the second country after Algeria in which was detected.
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http://dx.doi.org/10.1094/PDIS-08-19-1799-REDOI Listing
August 2020

Dissecting the Genetic Complexity of Fusarium Crown Rot Resistance in Wheat.

Sci Rep 2020 02 21;10(1):3200. Epub 2020 Feb 21.

Institute of Crop Science and Resource Conservation (INRES), Molecular Phytomedicine, Karlrobert- Kreiten Strasse 13, D-53115, Bonn, Germany.

Fusarium crown rot (FCR) is one of the most important diseases of wheat (Triticum aestivum L.). FCR is mainly caused by the fungal pathogens Fusarium culmorum and F. pseudograminearum. In order to identify new sources of resistance to FCR and to dissect the complexity of FCR resistance, a panel of 161 wheat accessions was phenotyped under growth room (GR) and greenhouse conditions (GH). Analysis of variance showed significant differences in crown rot development among wheat accessions and high heritability of genotype-environment interactions for GR (0.96) and GH (0.91). Mixed linear model analysis revealed seven novel quantitative trait loci (QTLs) linked to F. culmorum on chromosomes 2AL, 3AS, 4BS, 5BS, 5DS, 5DL and 6DS for GR and eight QTLs on chromosomes on 3AS, 3BS, 3DL, 4BS (2), 5BS, 6BS and 6BL for GH. Total phenotypic variances (R²) explained by the QTLs linked to GR and GH were 48% and 59%, respectively. In addition, five favorable epistasis interactions among the QTLs were detected for both GR and GH with and without main effects. Epistatic interaction contributed additional variation up to 21% under GR and 7% under GH indicating strong effects of environment on the expression of QTLs. Our results revealed FCR resistance responses in wheat to be complex and controlled by multiple QTLs.
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http://dx.doi.org/10.1038/s41598-020-60190-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7035263PMC
February 2020

Activity profiling of barley vacuolar processing enzymes provides new insights into the plant and cyst nematode interaction.

Mol Plant Pathol 2020 01 12;21(1):38-52. Epub 2019 Oct 12.

Department of Botany, Institute of Biology, Warsaw University of Life Sciences-SGGW, Warsaw, Poland.

Vacuolar processing enzymes (VPEs) play an important role during regular growth and development and defence responses. Despite substantial attempts to understand the molecular basis of plant-cyst nematode interaction, the mechanism of VPEs functioning during this interaction remains unknown. The second-stage Heterodera filipjevi juvenile penetrates host roots and induces the formation of a permanent feeding site called a syncytium. To investigate whether infection with H. filipjevi alters plant host VPEs, the studies were performed in Hordeum vulgare roots and leaves on the day of inoculation and at 7, 14 and 21 days post-inoculation (dpi). Implementing molecular, biochemical and microscopic methods we identified reasons for modulation of barley VPE activity during interaction with H. filipjevi. Heterodera filipjevi parasitism caused a general decrease of VPE activity in infected roots, but live imaging of VPEs showed that their activity is up-regulated in syncytia at 7 and 14 dpi and down-regulated at 21 dpi. These findings were accompanied by tissue-specific VPE gene expression patterns. Expression of the barley cystatin HvCPI-4 gene was stimulated in leaves but diminished in roots upon infestation. External application of cyclotides that can be produced naturally by VPEs elicits in pre-parasitic juveniles vesiculation of their body, enhanced formation of granules, induction of exploratory behaviour (stylet thrusts and head movements), production of reactive oxygen species (ROS) and final death by methuosis. Taken together, down-regulation of VPE activity through nematode effectors promotes the nematode invasion rates and leads to avoidance of the induction of the plant proteolytic response and death of the invading juveniles.
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http://dx.doi.org/10.1111/mpp.12878DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6913211PMC
January 2020

Genome-Wide Association Study for Multiple Biotic Stress Resistance in Synthetic Hexaploid Wheat.

Int J Mol Sci 2019 Jul 26;20(15). Epub 2019 Jul 26.

Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68583, USA.

Genetic resistance against biotic stress is a major goal in many wheat breeding programs. However, modern wheat cultivars have a limited genetic variation for disease and pest resistance and there is always a possibility of the evolution of new diseases and pests to overcome previously identified resistance genes. A total of 125 synthetic hexaploid wheats (SHWs; 2 = 6 = 42, AABBDD, L.) were characterized for resistance to fungal pathogens that cause wheat rusts (leaf; , stem; . f.sp. , and stripe; . f.sp. ) and crown rot (Fusarium spp.); cereal cyst nematode ( spp.); and Hessian fly (). A wide range of genetic variation was observed among SHWs for multiple (two to five) biotic stresses and 17 SHWs that were resistant to more than two stresses. The genomic regions and potential candidate genes conferring resistance to these biotic stresses were identified from a genome-wide association study (GWAS). This GWAS study identified 124 significant marker-trait associations (MTAs) for multiple biotic stresses and 33 of these were found within genes. Furthermore, 16 of the 33 MTAs present within genes had annotations suggesting their potential role in disease resistance. These results will be valuable for pyramiding novel genes/genomic regions conferring resistance to multiple biotic stresses from SHWs into elite bread wheat cultivars and providing further insights on a wide range of stress resistance in wheat.
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http://dx.doi.org/10.3390/ijms20153667DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6696463PMC
July 2019

Resistance and tolerance reactions of winter wheat lines to in Turkey.

J Nematol 2019 ;51:1-12

International Maize and Wheat Improvement Center (CIMMYT) , P.K. 39 Emek, 06511, Ankara , Turkey.

Nematodes attack cereal crops resulting in significant yield losses, estimated at 10%. The plant parasitic nematodes of the genus attack cereals, particularly wheat, causing costly financial losses due to impact on yield. The soil borne pathogens program at the International Maize and Wheat Improvement Center (CIMMYT) in Turkey has focused on screening wheat germplasm to identify sources of resistant varieties for almost 20 years. The aim of this current study was to validate the finding that resistant lines demonstrate resistant reactions under controlled conditions and to test whether they present tolerant reactions when challenged with cyst nematodes under two different locations in field conditions. The results of this study, including the check lines, indicated that 27 and 28 lines maintained their reactions to in Eskisehir and Yozgat field, respectively, and 23 lines were the same in both locations. In terms of tolerance, 3 and 13 lines proven to be tolerant and moderately tolerant to in Yozgat field. In Eskisehir field, 13 and 14 lines were tolerant and moderately tolerant. In both locations, L7 showed tolerance reaction, although it was susceptible. The majority of the resistant germplasm (60%, 14 lines) of screened lines from the Turkey CIMMYT-ICARDA (TCI) nursery were found to be resistant to both populations including L1, L3, L6, L15, L21, L26, and L34, whereas 17% (four lines) from the USA had the same reaction. L32 showed a high level of resistance and tolerance in both locations and could prove to be promising lines in the breeding programs. The International Winter Wheat Improvement Program (IWWIP) formerly used these resistant lines in the crossing block and subsequently distributed them to more than 150 international collaborators. Regression analysis revealed a negative correlation between yield and RF of in both nematode populations, which describes the negative impact of this pest on winter wheat. The results of this study are very important for breeding programs especially for the IWWIP, a joint program between the Turkish Ministry of Agriculture and Forestry, CIMMYT, and the International Centre for Agricultural Research in the Dry Areas (ICARDA).

Nematodes attack cereal crops resulting in significant yield losses, estimated at 10%. The plant parasitic nematodes of the genus attack cereals, particularly wheat, causing costly financial losses due to impact on yield. The soil borne pathogens program at the International Maize and Wheat Improvement Center (CIMMYT) in Turkey has focused on screening wheat germplasm to identify sources of resistant varieties for almost 20 years. The aim of this current study was to validate the finding that resistant lines demonstrate resistant reactions under controlled conditions and to test whether they present tolerant reactions when challenged with cyst nematodes under two different locations in field conditions. The results of this study, including the check lines, indicated that 27 and 28 lines maintained their reactions to in Eskisehir and Yozgat field, respectively, and 23 lines were the same in both locations. In terms of tolerance, 3 and 13 lines proven to be tolerant and moderately tolerant to in Yozgat field. In Eskisehir field, 13 and 14 lines were tolerant and moderately tolerant. In both locations, L7 showed tolerance reaction, although it was susceptible. The majority of the resistant germplasm (60%, 14 lines) of screened lines from the Turkey CIMMYT–ICARDA (TCI) nursery were found to be resistant to both populations including L1, L3, L6, L15, L21, L26, and L34, whereas 17% (four lines) from the USA had the same reaction. L32 showed a high level of resistance and tolerance in both locations and could prove to be promising lines in the breeding programs. The International Winter Wheat Improvement Program (IWWIP) formerly used these resistant lines in the crossing block and subsequently distributed them to more than 150 international collaborators. Regression analysis revealed a negative correlation between yield and RF of in both nematode populations, which describes the negative impact of this pest on winter wheat. The results of this study are very important for breeding programs especially for the IWWIP, a joint program between the Turkish Ministry of Agriculture and Forestry, CIMMYT, and the International Centre for Agricultural Research in the Dry Areas (ICARDA).
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http://dx.doi.org/10.21307/jofnem-2019-031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6929655PMC
January 2019

Resistance to Cereal Cyst Nematodes in Wheat and Barley: An Emphasis on Classical and Modern Approaches.

Int J Mol Sci 2019 Jan 19;20(2). Epub 2019 Jan 19.

National Engineering Laboratory for Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.

Cereal cyst nematodes (CCNs) are among the most important nematode pests that limit production of small grain cereals like wheat and barley. These nematodes alone are estimated to reduce production of crops by 10% globally. This necessitates a huge enhancement of nematode resistance in cereal crops against CCNs. Nematode resistance in wheat and barley in combination with higher grain yields has been a preferential research area for cereal nematologists. This usually involved the targeted genetic exploitations through natural means of classical selection breeding of resistant genotypes and finding quantitative trait luci (QTLs) associated with resistance genes. These improvements were based on available genetic diversity among the crop plants. Recently, genome-wide association studies have widely been exploited to associate nematode resistance or susceptibility with particular regions of the genome. Use of biotechnological tools through the application of various transgenic strategies for enhancement of nematode resistance in various crop plants including wheat and barley had also been an important area of research. These modern approaches primarily include the use of gene silencing, exploitation of nematode effector genes, proteinase inhibitors, chemodisruptive peptides and a combination of one or more of these approaches. Furthermore, the perspective genome editing technologies including CRISPR-Cas9 could also be helpful for improving CCN resistance in wheat and barley. The information provided in this review will be helpful to enhance resistance against CCNs and will attract the attention of the scientific community towards this neglected area.
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http://dx.doi.org/10.3390/ijms20020432DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6359373PMC
January 2019

Nematicidal Cyclic Lipodepsipeptides and a Xanthocillin Derivative from a Phaeosphariaceous Fungus Parasitizing Eggs of the Plant Parasitic Nematode Heterodera filipjevi.

J Nat Prod 2018 10 20;81(10):2228-2234. Epub 2018 Sep 20.

Department of Microbial Drugs , Helmholtz Centre for Infection Research , Inhoffenstrasse 7 , 38124 Braunschweig , Germany.

The new cyclic lipodepsipeptide ophiotine (1), two new arthrichitin derivatives named arthrichitins B (4) and C (5), a new xanthocillin-like alkaloid, xanthomide Z (2), and the previously described arthrichitin (3) were isolated from the liquid culture broth of a nematode-associated fungus with affinities to the genus Ophiosphaerella. The structural elucidation and determination of the absolute configuration of the new molecules were accomplished using a combination of spectroscopic and chemical techniques, including 1D and 2D NMR, HRMS, and Marfey's analysis. Opiotine (1) displayed moderate nematicidal activity against the host nematode ( Heterodera filipjevi), while xanthomide Z (2) exhibited very weak activity. Arthrichitin C (5) showed very weak cytotoxic effects on several cancer cell lines, with IC values in the range of 24-33 μM. Xanthomide Z is among few xanthocillin derivatives that comprise formamide functions instead of the cyano functions that are usually observed in this class of fungal alkaloids.
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http://dx.doi.org/10.1021/acs.jnatprod.8b00486DOI Listing
October 2018

Identification of Novel Quantitative Trait Loci Linked to Crown Rot Resistance in Spring Wheat.

Int J Mol Sci 2018 Sep 8;19(9). Epub 2018 Sep 8.

Global Wheat Program, International Maize and Wheat Improvement Center (CIMMYT), Ankara 06511, Turkey.

Crown rot (CR), caused by various species, is a major disease in many cereal-growing regions worldwide. is one of the most important species, which can cause significant yield losses in wheat. A set of 126 advanced International Maize and Wheat Improvement Center (CIMMYT) spring bread wheat lines were phenotyped against CR for field crown, greenhouse crown and stem, and growth room crown resistance scores. Of these, 107 lines were genotyped using Diversity Array Technology (DArT) markers to identify quantitative trait loci linked to CR resistance by genome-wide association study. Results of the population structure analysis grouped the accessions into three sub-groups. Genome wide linkage disequilibrium was large and declined on average within 20 cM (centi-Morgan) in the panel. General linear model (GLM), mixed linear model (MLM), and naïve models were tested for each CR score and the best model was selected based on quarantine-quarantine plots. Three marker-trait associations (MTAs) were identified linked to CR resistance; two of these on chromosome 3B were associated with field crown scores, each explaining 11.4% of the phenotypic variation and the third MTA on chromosome 2D was associated with greenhouse stem score and explained 11.6% of the phenotypic variation. Together, these newly identified loci provide opportunity for wheat breeders to exploit in enhancing CR resistance via marker-assisted selection or deployment in genomic selection in wheat breeding programs.
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http://dx.doi.org/10.3390/ijms19092666DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6165080PMC
September 2018

Occurrence of the Root-Knot Nematode species in Vegetable Crops in Souss Region of Morocco.

Plant Pathol J 2018 Aug 1;34(4):308-315. Epub 2018 Aug 1.

National Institute of Agronomic Research, UR- Integrated Crop Protection, Nematology Laboratory, National Institute of Agricultural Research (INRA), Agadir, Morocco.

Root-knot nematodes ' spp' are the most destructive group of plant parasitic nematodes causeing serious losses in vegetables crops and this damages worsened when crops grown under greenhouses conditions. In this sutdy, the distribution and characterization of root-knot nematode species collected from the Souss region of Morocco where vegetables crops intensively cultivated were determined by using both morphological and molecular tools. Out of the 110 samples collected from different greenhouses 91 (81.7%) were found to be infested with root-knot nematodes. Thirty-seven populations of root-knot nematodes were morphologically identified based on perineal patterns as well as molecularlly using species-specific primers. The obtained results indicated that and were identified in 86.4% and 13.5% of the total populations, respectively. The lowest incidence of root-knot nematodes (64%) was found in Toussous, whereas the highest frequencies of 100% and 90% were detected in Taddart and Biogra, respectively. As the majority of the samples have been infested with species; this indicates that there is an urgent need to provide farmers with a proper control strategy.
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http://dx.doi.org/10.5423/PPJ.OA.02.2018.0017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6097824PMC
August 2018

Inhabiting plant roots, nematodes, and truffles-Polyphilus, a new helotialean genus with two globally distributed species.

Mycologia 2018 Mar-Apr;110(2):286-299. Epub 2018 May 17.

c Department of Plant Anatomy , Institute of Biology, Eötvös Loránd University , Pázmány Péter sétány 1/C, H-1117 Budapest , Hungary.

Fungal root endophytes, including the common group of dark septate endophytes (DSEs), represent different taxonomic groups and potentially diverse life strategies. In this study, we investigated two unidentified helotialean lineages found previously in a study of DSE fungi of semiarid grasslands, from several other sites, and collected recently from a pezizalean truffle ascoma and eggs of the cereal cyst nematode Heterodera filipjevi. The taxonomic positions and phylogenetic relationships of 21 isolates with different hosts and geographic origins were studied in detail. Four loci, namely, nuc rDNA ITS1-5.8S-ITS2 (internal transcribed spacer [ITS]), partial 28S nuc rDNA (28S), partial 18S nuc rDNA (18S), and partial RNA polymerase II second-largest subunit (RPB2), were amplified and sequenced for molecular phylogenetic analyses. Analyses of similar ITS sequences from public databases revealed two globally distributed lineages detected in several biomes from different geographic regions. The host interaction of isolates from nematodes was examined using in vitro bioassays, which revealed that the fungi could penetrate nematode cysts and colonize eggs of H. filipjevi, confirming observations from field-collected samples. This is the first report of a DSE, and we are not aware of other helotialean fungal species colonizing the eggs of a plant-parasitic nematode. Neither conidiomata and conidia nor ascomata formation was detected in any of the isolates. Based on molecular phylogenetic analyses, these isolates represent a distinct lineage within the Helotiales in the Hyaloscyphaceae. For this lineage, we propose here the new genus Polyphilus represented by two new species, P. sieberi and P. frankenii.
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http://dx.doi.org/10.1080/00275514.2018.1448167DOI Listing
January 2019

Cereal Cyst Nematodes: A Complex and Destructive Group of Heterodera Species.

Plant Dis 2017 Oct 15;101(10):1692-1720. Epub 2017 Aug 15.

Crop Protection Research Area, Plant Sciences Unit, Research Institute for Agriculture, Fisheries and Food (ILVO), Merelbeke, Belgium.

Small grain cereals have served as the basis for staple foods, beverages, and animal feed for thousands of years. Wheat, barley, oats, rye, triticale, rice, and others are rich in calories, proteins, carbohydrates, vitamins, and minerals. These cereals supply 20% of the calories consumed by people worldwide and are therefore a primary source of energy for humans and play a vital role in global food and nutrition security. Global production of small grains increased linearly from 1960 to 2005, and then began to decline. Further decline in production is projected to continue through 2050 while global demand for these grains is projected to increase by 1% per annum. Currently, wheat, barley, and oat production exceeds consumption in developed countries, while in developing countries the consumption rate is higher than production. An increasing demand for meat and livestock products is likely to compound the demand for cereals in developing countries. Current production levels and trends will not be sufficient to fulfill the projected global demand generated by increased populations. For wheat, global production will need to be increased by 60% to fulfill the estimated demand in 2050. Until recently, global wheat production increased mostly in response to development of improved cultivars and farming practices and technologies. Production is now limited by biotic and abiotic constraints, including diseases, nematodes, insect pests, weeds, and climate. Among these constraints, plant-parasitic nematodes alone are estimated to reduce production of all world crops by 10%. Cereal cyst nematodes (CCNs) are among the most important nematode pests that limit production of small grain cereals. Heavily invaded young plants are stunted and their lower leaves are often chlorotic, forming pale green patches in the field. Mature plants are also stunted, have a reduced number of tillers, and the roots are shallow and have a "bushy-knotted" appearance. CCNs comprise a number of closely-related species and are found in most regions where cereals are produced.
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http://dx.doi.org/10.1094/PDIS-03-17-0355-FEDOI Listing
October 2017

Ijuhya vitellina sp. nov., a novel source for chaetoglobosin A, is a destructive parasite of the cereal cyst nematode Heterodera filipjevi.

PLoS One 2017 12;12(7):e0180032. Epub 2017 Jul 12.

Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut (JKI)-Federal Research Centre for Cultivated Plants, Braunschweig, Germany.

Cyst nematodes are globally important pathogens in agriculture. Their sedentary lifestyle and long-term association with the roots of host plants render cyst nematodes especially good targets for attack by parasitic fungi. In this context fungi were specifically isolated from nematode eggs of the cereal cyst nematode Heterodera filipjevi. Here, Ijuhya vitellina (Ascomycota, Hypocreales, Bionectriaceae), encountered in wheat fields in Turkey, is newly described on the basis of phylogenetic analyses, morphological characters and life-style related inferences. The species destructively parasitises eggs inside cysts of H. filipjevi. The parasitism was reproduced in in vitro studies. Infected eggs were found to harbour microsclerotia produced by I. vitellina that resemble long-term survival structures also known from other ascomycetes. Microsclerotia were also formed by this species in pure cultures obtained from both, solitarily isolated infected eggs obtained from fields and artificially infected eggs. Hyphae penetrating the eggshell colonised the interior of eggs and became transformed into multicellular, chlamydospore-like structures that developed into microsclerotia. When isolated on artificial media, microsclerotia germinated to produce multiple emerging hyphae. The specific nature of morphological structures produced by I. vitellina inside nematode eggs is interpreted as a unique mode of interaction allowing long-term survival of the fungus inside nematode cysts that are known to survive periods of drought or other harsh environmental conditions. Generic classification of the new species is based on molecular phylogenetic inferences using five different gene regions. I. vitellina is the only species of the genus known to parasitise nematodes and produce microsclerotia. Metabolomic analyses revealed that within the Ijuhya species studied here, only I. vitellina produces chaetoglobosin A and its derivate 19-O-acetylchaetoglobosin A. Nematicidal and nematode-inhibiting activities of these compounds have been demonstrated suggesting that the production of these compounds may represent an adaptation to nematode parasitism.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0180032PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5507501PMC
September 2017

Transgenic Strategies for Enhancement of Nematode Resistance in Plants.

Front Plant Sci 2017 9;8:750. Epub 2017 May 9.

International Maize and Wheat Improvement CenterAnkara, Turkey.

Plant parasitic nematodes (PPNs) are obligate biotrophic parasites causing serious damage and reduction in crop yields. Several economically important genera parasitize various crop plants. The root-knot, root lesion, and cyst nematodes are the three most economically damaging genera of PPNs on crops within the family Heteroderidae. It is very important to devise various management strategies against PPNs in economically important crop plants. Genetic engineering has proven a promising tool for the development of biotic and abiotic stress tolerance in crop plants. Additionally, the genetic engineering leading to transgenic plants harboring nematode resistance genes has demonstrated its significance in the field of plant nematology. Here, we have discussed the use of genetic engineering for the development of nematode resistance in plants. This review article also provides a detailed account of transgenic strategies for the resistance against PPNs. The strategies include natural resistance genes, cloning of proteinase inhibitor coding genes, anti-nematodal proteins and use of RNA interference to suppress nematode effectors. Furthermore, the manipulation of expression levels of genes induced and suppressed by nematodes has also been suggested as an innovative approach for inducing nematode resistance in plants. The information in this article will provide an array of possibilities to engineer resistance against PPNs in different crop plants.
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http://dx.doi.org/10.3389/fpls.2017.00750DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5422515PMC
May 2017

Association analysis of resistance to cereal cyst nematodes () and root lesion nematodes ( and ) in CIMMYT advanced spring wheat lines for semi-arid conditions.

Breed Sci 2016 Dec 25;66(5):692-702. Epub 2016 Oct 25.

Grains Research & Development Corporation (GRDC) , 4/4 National Circuit Barton 2600 ACT , Australia.

To identify loci linked to nematode resistance genes, a total of 126 of CIMMYT advanced spring wheat lines adapted to semi-arid conditions were screened for resistance to , , and , of which 107 lines were genotyped with 1,310 DArT. Association of DArT markers with nematode response was analyzed using the general linear model. Results showed that 11 markers were associated with resistance to (pathotype Ha21), 25 markers with resistance to , and 9 significant markers were identified to be linked with resistance to . In this work we confirmed that chromosome 4A (~90-105 cM) can be a source of resistance to as has been recently reported. Other significant markers were also identified on chromosomal regions where no resistant genes have been reported for both nematodes species. These novel QTL were mapped to chromosomes 5A, 6A, and 7A for ; on chromosomes 1A, 1B, 3A, 3B, 6B, 7AS, and 7D for ; and on chromosomes 1D, 2A, and 5B for and represent potentially new loci linked to resistance that may be useful for selecting parents and deploying resistance into elite germplasm adapted to regions where nematodes are causing problem.
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http://dx.doi.org/10.1270/jsbbs.15158DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5282747PMC
December 2016

Genome-Wide Association Study in Wheat Identifies Resistance to the Cereal Cyst Nematode Heterodera filipjevi.

Phytopathology 2016 10 23;106(10):1128-1138. Epub 2016 Aug 23.

First, fifth, sixth, and ninth authors: Institute of Crop Science and Resource Conservation (INRES), Molecular Phytomedicine, Karlrobert-Kreiten Strasse 13, D-53115 Bonn, Germany; second, fourth, and seventh authors: International Maize and Wheat Improvement Centre (CIMMYT), P.K. 39 06511, Emek, Ankara, Turkey; third and eighth authors: Institute of Crop Science and Resource Conservation (INRES), Plant Breeding, Katzenburgweg; and fifth author: Agricultural Research Center (ARC), Agricultural genetic Engineering Research Institute (AGERI), 9 Gama Street, Giza 12619, Egypt.

The cyst nematode Heterodera filipjevi is a plant parasite causing substantial yield loss in wheat. Resistant cultivars are the preferred method of controlling cyst nematodes. Association mapping is a powerful approach to detect associations between phenotypic variation and genetic polymorphisms; in this way favorable traits such as resistance to pathogens can be located. Therefore, a genome-wide association study of 161 winter wheat accessions was performed with a 90K iSelect single nucleotide polymorphism (SNP) chip. Population structure analysis grouped into two major subgroups and first principal component accounted 6.16% for phenotypic diversity. The genome-wide linkage disequilibrium across wheat was 3 cM. Eleven quantitative trait loci (QTLs) on chromosomes 1AL, 2AS, 2BL, 3AL, 3BL, 4AS, 4AL, 5BL, and 7BL were identified using a mixed linear model false discovery rate of P < 0.01 that explained 43% of total genetic variation. This is the first report of QTLs conferring resistance to H. filipjevi in wheat. Eight QTLs on chromosomes 1AL, 2AS, 2BL, 3AL, 4AL, and 5BL were linked to putative genes known to be involved in plant-pathogen interactions. Two other QTLs on 3BL and one QTL on 7BL linked to putative genes known to be involved in abiotic stress.
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http://dx.doi.org/10.1094/PHYTO-02-16-0054-FIDOI Listing
October 2016