Showing papers on "Heterodera avenae published in 2015"
TL;DR: A lack of expertise and recognition of CCNs as a factor limiting wheat production potential, combined with inappropriate breeding strategies and slow screening processes limit genetic gains for resistance to CCNs.
Abstract: Cereal cyst nematodes (CCNs) can cause significant economic yield losses alone or in combination with other biotic and abiotic factors. The damage caused by these nematodes can be enormous when they occur in a disease complex, particularly in areas subject to water stress. Of the 12 valid CCN species, Heterodera avenae, H. filipjevi, and H. latipons are considered the most economically important in different parts of the world. This paper reviews current approaches to managing CCNs via genetic resistance, biological agents, cultural practices, and chemical strategies. Recent research within the soil borne pathogen program of the International Maize and Wheat Improvement Center has focused on germplasm screening, the potential of this germplasm as sources of resistance, and how to incorporate new sources of resistance into breeding programs. Breeding for resistance is particularly complicated and difficult when different species and pathotypes coexist in nature. A lack of expertise and recognition of CCNs as a factor limiting wheat production potential, combined with inappropriate breeding strategies and slow screening processes limit genetic gains for resistance to CCNs.
70 citations
TL;DR: Ha-annexin transcripts were expressed within the subventral gland cells of the pre-parasitic second-stage juveniles by in situ hybridization and Ha-ANNEXIN targeted a point in the mitogen-activated protein kinase (MAPK) signaling pathway downstream of two kinases MKK1 and NPK1 in N. benthamiana.
Abstract: Parasitism genes encoding secreted effector proteins of plant-parasitic nematodes play important roles in facilitating parasitism. An annexin-like gene was isolated from the cereal cyst nematode Heterodera avenae (termed Ha-annexin) and had high similarity to annexin 2, which encodes a secreted protein of Globodera pallida. Ha-annexin encodes a predicted 326 amino acid protein containing four conserved annexin domains. Southern blotting revealed that there are at least two homologies in the H. avenae genome. Ha-annexin transcripts were expressed within the subventral gland cells of the pre-parasitic second-stage juveniles by in situ hybridization. Additionally, expression of these transcripts were relatively higher in the parasitic second-stage juveniles by quantitative real-time RT-PCR analysis, coinciding with the time when feeding cell formation is initiated. Knockdown of Ha-annexin by method of barley stripe mosaic virus-based host-induced gene silencing (BSMV-HIGS) caused impaired nematode infections at 7 dpi and reduced females at 40 dpi, indicating important roles of the gene in parasitism at least in early stage in vivo. Transiently expression of Ha-ANNEXIN in onion epidermal cells and Nicotiana benthamiana leaf cells showed the whole cell-localization. Using transient expression assays in N. benthamiana, we found that Ha-ANNEXIN could suppress programmed cell death triggered by the pro-apoptotic mouse protein BAX and the induction of marker genes of PAMP-triggered immunity (PTI) in N. benthamiana. In addition, Ha-ANNEXIN targeted a point in the mitogen-activated protein kinase (MAPK) signaling pathway downstream of two kinases MKK1 and NPK1 in N. benthamiana.
54 citations
TL;DR: Dynamic transcriptional changes in uncharacterized HvCslF genes, possibly involved in (1,3;1,4)-β-glucan synthesis, suggest a role for these genes in the CCN infection process.
Abstract: Free to read at publisher Summary - Heterodera avenae (cereal cyst nematode, CCN) infects the roots of barley (Hordeum vulgare) forming syncytial feeding sites. In resistant host plants, relatively few females develop to maturity. Little is known about the physiological and biochemical changes induced during CCN infection. - Responses to CCN infection were investigated in resistant (Rha2) and susceptible barley cultivars through histological, compositional and transcriptional analysis. - Two phases were identified that influence CCN viability, including feeding site establishment and subsequent cyst maturation. Syncytial development progressed faster in the resistant cultivar Chebec than in the susceptible cultivar Skiff, and was accompanied by changes in cell wall polysaccharide abundance, particularly (1,3;1,4)-β-glucan. Transcriptional profiling identified several glycosyl transferase genes, including CELLULOSE SYNTHASE-LIKE F10 (HvCslF10), which may contribute to differences in polysaccharide abundance between resistant and susceptible cultivars. - In barley, Rha2-mediated CCN resistance drives rapid deterioration of CCN feeding sites, specific changes in cell wall-related transcript abundance and changes in cell wall composition. During H. avenae infection, (1,3;1,4)-β-glucan may influence CCN feeding site development by limiting solute flow, similar to (1,3)-β-glucan during dicot cyst nematode infections. Dynamic transcriptional changes in uncharacterized HvCslF genes, possibly involved in (1,3;1,4)-β-glucan synthesis, suggest a role for these genes in the CCN infection process.
38 citations
TL;DR: Large-scale identification of wheat resistance genes were processed by comparative transcriptomic analysis and revealed that phospholipases associated with ROS production played vital roles in early defense responses to H. avenae via involvement in diverse defense-related pathways as a hub switch.
Abstract: Cereal cyst nematode Heterodera avenae, an important soil-borne pathogen in wheat, causes numerous annual yield losses worldwide, and use of resistant cultivars is the best strategy for control. However, target genes are not readily available for breeding resistant cultivars. Therefore, comparative transcriptomic analyses were performed to identify more applicable resistance genes for cultivar breeding. The developing nematodes within roots were stained with acid fuchsin solution. Transcriptome assemblies and redundancy filteration were obtained by Trinity, TGI Clustering Tool and BLASTN, respectively. Gene Ontology annotation was yielded by Blast2GO program, and metabolic pathways of transcripts were analyzed by Path_finder. The ROS levels were determined by luminol-chemiluminescence assay. The transcriptional gene expression profiles were obtained by quantitative RT-PCR. The RNA-sequencing was performed using an incompatible wheat cultivar VP1620 and a compatible control cultivar WEN19 infected with H. avenae at 24 h, 3 d and 8 d. Infection assays showed that VP1620 failed to block penetration of H. avenae but disturbed the transition of developmental stages, leading to a significant reduction in cyst formation. Two types of expression profiles were established to predict candidate resistance genes after developing a novel strategy to generate clean RNA-seq data by removing the transcripts of H. avenae within the raw data before assembly. Using the uncoordinated expression profiles with transcript abundance as a standard, 424 candidate resistance genes were identified, including 302 overlapping genes and 122 VP1620-specific genes. Genes with similar expression patterns were further classified according to the scales of changed transcript abundances, and 182 genes were rescued as supplementary candidate resistance genes. Functional characterizations revealed that diverse defense-related pathways were responsible for wheat resistance against H. avenae. Moreover, phospholipase was involved in many defense-related pathways and localized in the connection position. Furthermore, strong bursts of reactive oxygen species (ROS) within VP1620 roots infected with H. avenae were induced at 24 h and 3 d, and eight ROS-producing genes were significantly upregulated, including three class III peroxidase and five lipoxygenase genes. Large-scale identification of wheat resistance genes were processed by comparative transcriptomic analysis. Functional characterization showed that phospholipases associated with ROS production played vital roles in early defense responses to H. avenae via involvement in diverse defense-related pathways as a hub switch. This study is the first to investigate the early defense responses of wheat against H. avenae, not only provides applicable candidate resistance genes for breeding novel wheat cultivars, but also enables a better understanding of the defense mechanisms of wheat against H. avenae.
37 citations
TL;DR: The morphological and molecular characteristics of 41 populations of cereal cyst nematodes (Heterodera avenae group) collected in Adana, Osmaniye, Kahramanmaras, Hatay, Gaziantep, and Kilis provinces in the eastern Mediterranean region of Turkey were studied and showed the presence of 3 HeterodERA species.
Abstract: The morphological and molecular characteristics of 41 populations of cereal cyst nematodes (Heterodera avenae group) collected in Adana, Osmaniye, Kahramanmaras, Hatay, Gaziantep, and Kilis provinces in the eastern Mediterranean region of Turkey were studied. The morphological characters and morphometric features of second-stage juveniles and cysts showed the presence of 3 Heterodera species: H. avenae, H. filipjevi, and H. latipons. All morphological values of these distinct populations were very similar to those previously described for these species. Genetic variation was observed among the identified cyst nematode species H. avenae, H. filipjevi, and H. latipons. Intraspecific polymorphism was observed within H. avenae and H. latipons but not in H. filipjevi populations. Molecular analysis using ITS regions of rDNA confirmed the identities of the 3 Heterodera species. According to our results, 75% of isolates were identified as H. avenae, 15% as H. latipons, and 10% as H. filipjevi.
20 citations
TL;DR: Better insights are provided into the incompatible interaction between H. avenae and the host plant Ae.
Abstract: One of the reasons for the progressive yield decline observed in cereals production is the rapid build-up of populations of the cereal cyst nematode (CCN, Heterodera avenae). These nematodes secrete so-call effectors into their host plant to suppress the plant defense responses, alter plant signaling pathways and then induce the formation of syncytium after infection. However, little is known about its molecular mechanism and parasitism during incompatible infection. To gain insight into its repertoire of parasitism genes, we investigated the transcriptome of the early parasitic second-stage (30 hours, 3 days and 9 days post infection) juveniles of the CCN as well as the CCN infected tissue of the host Aegilops variabilis by Illumina sequencing. Among all assembled unigenes, 681 putative genes of parasitic nematode were found, in which 56 putative effectors were identified, including novel pioneer genes and genes corresponding to previously reported effectors. All the 681 CCN unigenes were mapped to 229 GO terms and 200 KEGG pathways, including growth, development and several stimulus-related signaling pathways. Sixteen clusters were involved in the CCN unigene expression atlas at the early stages during infection process, and three of which were significantly gene-enriched. Besides, the protein-protein interaction network analysis revealed 35 node unigenes which may play an important role in the plant-CCN interaction. Moreover, in a comparison of differentially expressed genes between the pre-parasitic juveniles and the early parasitic juveniles, we found that hydrolase activity was up-regulated in pre J2s whereas binding activity was upregulated in infective J2s. RT-qPCR analysis on some selected genes showed detectable expression, indicating possible secretion of the proteins and putative role in infection. This study provided better insights into the incompatible interaction between H. avenae and the host plant Ae. varabilis. Moreover, RNAi targets with potential lethality were screened out and primarily validated, which provide candidates for engineering-based control of cereal cyst nematode in crops breeding.
20 citations
Journal Article•
TL;DR: The sequence and phylogenetic analysis of the coxI mtDNA gene sequences and the PCR-coxI-RFLP separate H. sturhani sp.
Abstract: Heterodera sturhani sp. n. is described as a new species from the Heterodera avenae complex. The new species is morphologically similar to H. pratensis and H. riparia in many characteristics of cysts and second-stage juveniles. It can be differentiated from H. pratensis by smaller cyst sizes and from H. riparia by longer body and tail lengths of the second-stage juveniles. The sequence and phylogenetic analysis of the coxI mtDNA gene sequences and the PCR-coxI-RFLP separate H. sturhani sp. n. from all other species of the H. avenae complex. Phylogenetic analysis of the coxI gene sequences enables discrimination between A (France) and B (Syria) types of H. avenae. The independent species status of H. australis is confirmed. The multiple species concept of the cereal cyst nematodes is proposed and discussed.
19 citations
TL;DR: The addition of over 600 markers to improve an existing linkage map for the Trident/Molineux wheat population is reported, and Cre8 was mapped as a large-effect quantitative trait locus (QTL) near the distal end of 6BL.
Abstract: The cereal cyst nematode (CCN, Heterodera avenae Woll.) resistance locus Cre8 on the long arm of chromosome 6B (6BL) of wheat (Triticum aestivum L.) is effective in lowering the nematode population in soil. Identification of reliable and high-throughput molecular markers linked to the Cre8 locus is important for the successful deployment of Cre8-derived resistance in wheat breeding programs. Here, we report the addition of over 600 markers to improve an existing linkage map for the Trident/Molineux wheat population. With the improved map, Cre8 was mapped as a large-effect quantitative trait locus (QTL) near the distal end of 6BL. This QTL explained up to 35 % of the phenotypic variation in CCN resistance. New marker assays were developed for DNA polymorphisms in the Cre8 region. Seven molecular markers closely linked with Cre8 (at 0.9, 2.2 or 5.9 cM from the estimated QTL position) were found to be diagnostic across a panel of wheat cultivars and are recommended for use in marker-assisted selection of the Cre8 resistance locus in wheat breeding. Prospects for the isolation of the causal gene are discussed.
16 citations
TL;DR: The discovery of H. filipjevi-infested fields in eastern Washington is reported, thereby extending the known distribution of the cereal cyst nematode Heterodera avenae in the United States.
Abstract: The cereal cyst nematode Heterodera avenae suppresses wheat production in the western United States. A second species of cereal cyst nematode, H. filipjevi, was identified in eastern Oregon during 2008. This paper reports the discovery of H. filipjevi–infested fields in eastern Washington, thereby extending the known distribution of H. filipjevi in the United States. The identity of H. filipjevi was determined and confirmed by species-specific polymerase chain reaction (PCR), PCR-restriction fragment length polymorphism (RFLP), sequencing, and cyst morphology. Soils that were collected from naturally infested fields in Washington were used to compare the virulence of H. avenae and H. filipjevi on six spring wheat cultivars under controlled-environment conditions. Noninfested soils from nearby fields were used as controls. Cultivars Ouyen and WB Rockland were resistant to H. avenae and susceptible to H. filipjevi. Cultivars Sonmez and SY Steelhead were resistant to H. filipjevi and susceptible to ...
15 citations
TL;DR: Because the pathotypes of the two tested CCN populations in Beijing and Qinghai were not identical to any of the 13 pathotypes previously characterized by the test assortment, Daxing and Huangyuan populations were classified as the new pathotypes, named Ha91.
14 citations
TL;DR: Morphological and molecular diversity among populations of cereal cyst nematodes from wheat production areas in Ismailia province, Egypt, was investigated using light microscopy, ITS-RFLP and sequencing of the rDNA-ITS.
Abstract: Morphological and molecular diversity among populations of cereal cyst nematodes (CCN) from wheat production areas in Ismailia province, Egypt, was investigated using light microscopy, ITS-RFLP and sequencing of the rDNA-ITS. CCN were found in five out of seven regions in Ismailia, the highest incidence being found in El Shark (West Sinai). The Egyptian populations were identified as H. avenae according to morphometrics of cyst vulval cone and second-stage juveniles. No differences in ITS-RFLP patterns generated by 17 restriction enzymes were detected among the Egyptian populations although the Egyptian populations could be distinguished from German populations of H. avenae and H. filipjevi. The analyses of ITS region sequences confirmed the species identification of the Egyptian populations as they clustered with H. avenae populations from Iran, Saudi Arabia, India, Israel and China.
01 Jan 2015
TL;DR: Nematodes belonging to the phylum Nematoda or Nemata are the most abundant multicellular animal that inhabit in almost all the environments and are beneficial to maintain soil health, and a few of them are also useful for insect–pest management.
Abstract: Nematodes belonging to the phylum Nematoda or Nemata are the most abundant multicellular animal that inhabit in almost all the environments. Nematodes can parasitize plants, animals, insects, etc. Some plant parasitic nematodes (PPNs) are capable of causing disease on many economically important crops grown in India and attained the status of pests for substantial reduction of crop yield. Many free-living nematodes are beneficial to maintain soil health, and a few of them (entomopathogenic) are also useful for insect–pest management. Nematodes are introduced giving their general characteristics, morphological differentiation of PPN orders (Tylenchida, Aphelenchida, Dorylaimida and Triplonchida), a simple outline classification of PPNs, types of nematode parasitism, nature of nematode problems, field diagnosis based on disease symptoms, plant–nematode interaction and nematode interactions with other pathogens. Economically important phytonematodes such as root-knot (Meloidogyne spp.), potato cyst (Globodera rostochiensis and G. pallida), wheat seed gall (Anguina tritici), cereal cyst (Heterodera avenae), pigeon pea cyst (Heterodera cajani), reniform (Rotylenchulus reniformis), foliar (Aphelenchoides besseyi in tuberose, A. ritzemabosi in chrysanthemum), rice stem (Ditylenchus angustus), white tip (A. besseyi), rice root-knot (M. graminicola), rice root (Hirschmanniella spp.), rice cyst (Heterodera oryzicola), burrowing (Radopholus similis), citrus (Tylenchulus semipenetrans) and root lesion (Pratylenchus spp.) nematodes are illustrated along with their distribution, characteristic symptoms, biology and up-to-date management options available in India.
TL;DR: The use of the mitochondrial cytochrome oxidase subunit 1 (COI) gene is reported on to develop qPCR assays that could be used for the identification and quantification of H. avenae and H. latipons, providing a sensitive and valid tool for rapid detection and quantifying of the two species whether they occur alone or in mixtures with other species.
Abstract: Twelve Heterodera species are considered of major economic significance in cereals, of which Heterodera avenae, H. latipons and H. filipjevi are the most important. Precise identification and quantification of these nematodes are necessary to develop effective integrated pest control. This study reports on the use of the mitochondrial cytochrome oxidase subunit 1 (COI) gene to develop qPCR assays that could be used for the identification and quantification of H. avenae and H. latipons. Two qPCR primer sets, each comprising two primers and a probe, were designed for each of both species. After optimization, the qPCR assays using a single second-stage juvenile (J2) were able to identify and quantify H. avenae and H. latipons. Their specificity was confirmed by the lack of amplification of J2 of 14 other Heterodera species. A qPCR using DNA extracted from 120 J2 + eggs of H. avenae and H. latipons resulted in steady Ct-values (Ct = 22.33 ± 0.1 and Ct = 21.83 ± 0.12, respectively). Dilution series of DNA extracted from 120 J2 + eggs of the two species were made. The assays for both species resulted in a standard curve showing a highly significant linearity between the Ct-values and the dilution rates (R2 = 0.99; slope = −3.03 and R2 = 0.99; slope = −3.28 for H. avenae and H. latipons, respectively). The two qPCR assays provide a sensitive and valid tool for rapid detection and quantification of the two species whether they occur alone or in mixtures with other species.
TL;DR: A survey was conducted in north-eastern Syria to assess the distribution of CCN in the main wheat and barley growing areas, and revealed that 62% of the fields were infested with the three Heterodera species: H. avenae, H. filipjevi and H. latipons.
Abstract: Cereal cyst nematodes (CCN) are important plant-parasitic nematodes of wheat and barley, and exist in most of the cereal growing regions of the world. As there is limited information on the nature and distribution of CCN species in Syria, a survey was conducted in north-eastern Syria to assess the distribution of CCN in the main wheat and barley growing areas. In the summer of 2009, a total of 167 composite soil samples were collected from 167 wheat and barley fields. Cysts were extracted from soil using the Fenwick can technique, then quantified and identified up to the species level by using both morphological and molecular methods. The study revealed that 62% of the fields were infested with the three Heterodera species: H. avenae, H. filipjevi and H. latipons. However, the most prevalent species was H. latipons, which was present in 76% of the infested samples, while it occurred alone in 67% of those samples. Heterodera avenae was detected singly in 20% of the samples, while 11% consisted of mixed populations with other species. Heterodera filipjevi was never detected alone; it was found mixed with H. avenae and/or H. latipons in 9% of the samples. The high number of extracted cysts (up to 116 cysts × 200 g−1 of soil) is most likely related to the monoculture practiced in that region and the fact that growers are unaware of the existence of resistant varieties.
TL;DR: The study indicates that the essential oil of V. amurensis roots and its two major constituents, isovaleric acid and 3-methylvaleric acid, have a potential to be developed to natural nematicides for the control of cereal cyst nematodes.
Abstract: Purpose : To investigate the chemical composition and nematicidal activity of the essential oil of Valeriana amurensis roots against cereal cyst nematodes ( Heterodera avenae) . Methods : The essential oil of V. amurensis roots was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromaotography-mass spectrometry (GC-MS). The nematicidal activity of the essential oil and its major constituents was determined against second stage juveniles of H. avenae. Results : A total of 33 components of the essential oil were identified. The major constituents were bornyl acetate (12.5 %), patchoulol (11.6 %), caryophyllene (8.2 %), 3-methylvaleric acid (7.3 %) and isovaleric acid (6.5 %). The essential oil exhibited nematicidal activity against H. avenae with a medium lethal concentration (LC 50 ) value of 311.6 μg/mL. The major constituents, isovaleric acid and 3- methylvaleric acid, exhibited nematicidal activity against H. avenae with LC 50 of 218.2 and 683.8 μg/mL, respectively. Conclusion : The study indicates that the essential oil of V. amurensis roots and its two major constituents, isovaleric acid and 3-methylvaleric acid, have a potential to be developed to natural nematicides for the control of cereal cyst nematodes. Keywords : Valeriana amurensis, Heterodera avenae , Nematicidal activity, Isovaleric acid, 3- Methylvaleric acid, Essential oil, Cereal cyst nematodes
Journal Article•
TL;DR: Results show that the tested wheat genotypes were significantly different in field performance and resistance to CCN, and Cre3, Cre1 and other Cre resistance genes are now used in marker-assisted selection (MAS) programs to identify CCN-resistant wheat genotype.
Abstract: The cereal cyst nematode (CCN), Heterodera avenae Woll., is a devastating root nematode parasite of wheat (Triticum aestivum L.). This study aimed to screen wheat germplasm for resistance to CCN. The performance of 17 genetically diverse wheat genotypes (local and international material) were evaluated for two years (2009 and 2010) in a H. avenae-naturally-infested field at the Hial region, north Saudi Arabia. Results show that the tested wheat genotypes were significantly different in field performance and resistance to CCN. The grain yield ranged from 4.58 tons/ha for cv. Yecora Rojo (the susceptible) to 8.2 tons/ha for the genotype 15SAWYT-31. Ten local genotypes were designated as resistant. The local cv. KSU 119 was the most resistant genotype (no. cysts/plant = 0.7) among all the genotypes tested. In addition, microsatellite markers linked to Cre1 and Cre3 genes were used. The dendogram generated using SSR data divided wheat genotypes into two main clusters. Ten out of 17 wheat genotypes (LNM-72, LNM-99, LNM-126, LNM-136, KSU118, L11-8, L11-17, L11-21, KSU 119, and AUS-30851) had both Cre genes and were found in the same sub-cluster. All these genotypes, except AUS-30851, LNM-72 and L11-17, were found to be the resistant to CCN. Therefore, Cre3, Cre1 and other Cre resistance genes are now used in our marker-assisted selection (MAS) programs to identify CCN-resistant wheat genotypes.
Journal Article•
TL;DR: This paper presents a meta-analysis of 148 cases of Crimean Tournaisian whipworm infestation over a 25-year period from 1991 to 2002, which shows clear patterns of decline in the number of cases diagnosed and the severity of the infections.
Abstract: Mikhail V. Pridannikov , Tatiana P. Suprunova, Daria V. Shumilina, Lyudmila A. Limantseva, Andrea M. Skantar, Zafar A. Handoo and David J. Chitwood 1Russian Research Institute of Phytopathology, Institute Street 5, 143050, Bolshie Vyazyomy, Moscow Region, Russia 2Centre of Parasitology, A.N. Severtsov Institute Ecology and Evolution, Russian Academy of Sciences, Leninskii Prospect 33, 119071, Moscow, Russia 3Laboratory of Biotechnology, Russian Research Institute of Vegetable Breeding and Seed Production, Selektsionnaya Street 14, 127434, VNIISSOK, Moscow Region, Russia 4Nematology Laboratory, USDA, ARS, Beltsville Agricultural Research Center, 20705, Beltsville, MD, USA e-mail: Mikhail.Pridannikov@yahoo.com
Journal Article•
TL;DR: Three populations of H eterodera avenae collected from Wheat – Maize, Wheat – Cotton and Wheat – Rice rotation fields were characterized and it was concluded that all the three populations belonged to same pathotype i.e., Ha 41 pathotype of Ha1 group.
Abstract: Three populations of H eterodera avenae collected from Wheat – Maize, Wheat – Cotton and Wheat – Rice rotation fields were characterized using two sets of Host differentials i.e., CCNHD 1982 and CCNHD Modified recieved from CIMMYT, Maxico. Reaction of all the host differentials was mostly the same to all three populations. Host differentials Ansi, Ortalan, Morocco and Bajo Aragon (CCNHD 1982) and VP1620 (CCNHD Modified) were resistant. The cultivars; Capa, Zita, Silva KVL 191, Siri, 1.376; CC4658, Iskamish K-2-Light, Martin 403-2, MK H. 72-646, Psathias and AUS 10894 from CCNHD 1982, while Raj 1, Croc_1/Ae.Squarrosa(224)// Opata//020615 and F372 from CCNHD Modified were moderately resistant to all three populations. Rest of the host differentials were categorized into moderately resistant to highly susceptible to one or other population. On the basis of the results obtained and compared with results of Andersen and Andersen (1982), Rivoal and Cook (1993) and Subbotin et al (2010), it was concluded that all the three populations belonged to same pathotype i.e., Ha 41 pathotype of Ha1 group.