scholarly journals Distribution and identification of luteovirids affecting chickpea in Sudan

2021 ◽  
Vol 60 (2) ◽  
pp. 199-214
Author(s):  
Abdulrahman MOUKAHEL ◽  
Safaa G. KUMARI ◽  
Abdelmagid Adlan HAMED ◽  
Murray SHARMAN ◽  
Seid AHMED

In Sudan yellowing viruses are key production constraints in pulse crops. Field surveys were carried out to identify luteovirids affecting chickpea crops in the major production regions (Gezira Scheme and River Nile State). A total of 415 chickpea plant samples with yellowing and stunting symptoms were collected during the 2013, 2015 and 2018 growing seasons. Serological results (Tissue-blot immunoassays) showed that Luteoviridae and Chickpea chlorotic dwarf virus (CpCDV, genus Mastrevirus, family Geminiviridae) were the most common viruses, with rare infections with Faba bean necrotic yellows virus (FBNYV, genus Nanovirus, family Nanoviridae). Some samples reacted only with a broad-spectrum luteovirid monoclonal antibody (5G4-MAb), and others showed cross reactions between the specific monoclonal antibodies, suggesting the occurrence of new luteovirid variants. Serological results were confirmed by amplification with reverse transcription-polymerase chain reaction (RT-PCR) and sequencing of the partial coat protein gene. Molecular analyses provided a basic, sufficient and reliable characterization for four viruses affecting chickpea that belong to Polerovirus (family Luteoviridae). These were Cucurbit aphid-borne yellows virus (CABYV), Pepper vein yellows virus (PeVYV), Pepo aphid-borne yellows virus (PABYV) and Cotton leafroll dwarf virus (CLRDV), that shared high similarity with the type sequences. Phylogenetic analyses also revealed high similarity to luteovirid species. This study has established reliable, rapid and sensitive molecular tools for the detection of luteovirid species.

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1149
Author(s):  
Dina M. Metwally ◽  
Isra M. Al-Turaiki ◽  
Najwa Altwaijry ◽  
Samia Q. Alghamdi ◽  
Abdullah D. Alanazi

We analyzed the blood from 400 one-humped camels, Camelus dromedarius (C. dromedarius), in Riyadh and Al-Qassim, Saudi Arabia to determine if they were infected with the parasite Trypanosoma spp. Polymerase chain reaction (PCR) targeting the internal transcribed spacer 1 (ITS1) gene was used to detect the prevalence of Trypanosoma spp. in the camels. Trypanosoma evansi (T. evansi) was detected in 79 of 200 camels in Riyadh, an infection rate of 39.5%, and in 92 of 200 camels in Al-Qassim, an infection rate of 46%. Sequence and phylogenetic analyses revealed that the isolated T. evansi was closely related to the T. evansi that was detected in C. dromedarius in Egypt and the T. evansi strain B15.1 18S ribosomal RNA gene identified from buffalo in Thailand. A BLAST search revealed that the sequences are also similar to those of T. evansi from beef cattle in Thailand and to T. brucei B8/18 18S ribosomal RNA from pigs in Nigeria.


2021 ◽  
pp. 1-28
Author(s):  
Yoshimasa Kumekawa ◽  
Haruka Fujimoto ◽  
Osamu Miura ◽  
Ryo Arakawa ◽  
Jun Yokoyama ◽  
...  

Abstract Harvestmen (Arachnida: Opiliones) are soil animals with extremely low dispersal abilities that experienced allopatric differentiation. To clarify the morphological and phylogenetic differentiation of the endemic harvestman Zepedanulus ishikawai (Suzuki, 1971) (Laniatores: Epedanidae) in the southern part of the Ryukyu Archipelago, we conducted molecular phylogenetic analyses and divergence time estimates based on CO1 and 16S rRNA sequences of mtDNA, the 28S rRNA sequence of nrDNA, and the external morphology. A phylogenetic tree based on mtDNA sequences indicated that individuals of Z. ishikawai were monophyletic and were divided into clade I and clade II. This was supported by the nrDNA phylogenetic tree. Although clades I and II were distributed sympatrically on all three islands examined (Ishigaki, Iriomote, and Yonaguni), heterogeneity could not be detected by polymerase chain reaction–restriction fragment length polymorphism of nrDNA, indicating that clades I and II do not have a history of hybridisation. Also, several morphological characters differed significantly between individuals of clade I and clade II. The longstanding isolation of the southern Ryukyus from the surrounding islands enabled estimation of the original morphological characters of both clades of Z. ishikawai.


Plant Disease ◽  
2020 ◽  
Vol 104 (10) ◽  
pp. 2742
Author(s):  
Travis R. Faske ◽  
Daisy Stainton ◽  
Nina Aboughanem-Sabanadzovic ◽  
Tom W. Allen

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Sonjoy Kumar Borthakur ◽  
Dilip Kumar Deka ◽  
Saidul Islam ◽  
Dilip Kumar Sarma ◽  
Prabhat Chandra Sarmah

The aim of the present study was to determine the prevalence ofDirofilaria immitisin stray, pet, and working dogs (n=413, 266, and 103, resp.) from Guwahati (Assam) and Aizawl (Mizoram), areas located in two Northeastern States of India. Diagnostic methods applied were microscopy (wet film and Knott’s concentration technique), immunological test (Ag ELISA by SNAP 4Dx ELISA kit), and molecular tools (polymerase chain reaction and sequencing), which evidenced 11.38, 18.03, and 13.93% of positive animals, respectively. No significant differences were observed by area (18.23% versus 17.68%) nor by sex (18.1% versus 17.9%), whereas stray dogs proved more infected than other groups (P<0.05). ELISA test evidenced an overall 22.69% of occult infections, mainly in working dogs (60%), and molecular techniques detectedDirofilaria (Nochtiella) repensin 4 stray dogs from Guwahati. Characterization ofD. immitisisolates for ITS-2 region showed close identity with South Asian isolates.


2020 ◽  
Vol 21 (2) ◽  
pp. 142-143 ◽  
Author(s):  
Trey Price ◽  
Rodrigo Valverde ◽  
Raghuwinder Singh ◽  
Jeff Davis ◽  
Sebe Brown ◽  
...  

Cotton leafroll dwarf virus (CLRDV) has recently been discovered in the southern United States. The virus is transmitted by the cotton aphid and causes numerous symptoms including foliar chlorosis, distortion, leaf cupping, and reddened leaf veins. These symptoms were observed in a field in northeast Louisiana during the summer of 2019 approximately 2 weeks after cotton aphid infestation. Grafting infected cotton plants with healthy ones resulted in similar symptom development, and molecular diagnosis initially indicated and then confirmed the presence of CLRDV in sampled and grafted specimens, respectively. This the first report of CLRDV in Louisiana.


2019 ◽  
Vol 94 ◽  
Author(s):  
A. Santacruz ◽  
C.P. Ornelas-García ◽  
G. Pérez-Ponce de León

AbstractAmong fish parasitic nematodesRhabdochonais one of the most speciose genera, withc.100 species. Twelve congeneric species occur in Mexican freshwater fishes, in a region located between the Nearctic and Neotropical biogeographical regions. Host association and biogeographical history have determined the high species richness ofRhabdochonain Mexico. One of these species,Rhabdochona mexicana, is highly specific to the characid genusAstyanax.Characids are a group of freshwater fish with Neotropical affinity. In this paper, we explore the genetic diversity ofR. mexicanathrough samples obtained from populations ofAstyanaxspp. across river basins of Mexico and Guatemala. Sequences of one mitochondrial and two ribosomal genes were obtained from 38 individuals and analysed using Maximum Likelihood and Bayesian Inference analysis. Phylogenetic analyses usingcox1, and a concatenated alignment of 18S + 28S +cox1 recovered two genetic lineages. One of them corresponded withR. mexicana sensu stricto; this lineage included three reciprocally monophyletic subgroups; the other lineage was highly divergent and represented a putative candidate species. A detailed morphological study was conducted to corroborate the molecular findings. We describe a new species herein and discuss the implications of using molecular tools to increase our knowledge about the diversity of a speciose genus such asRhabdochona.


2011 ◽  
Vol 52 (No. 9) ◽  
pp. 392-401 ◽  
Author(s):  
N. Bukvayová ◽  
M. Henselová ◽  
V. Vajcíková ◽  
T. Kormanová

The aim of the study was to monitor the incidence and to detect the presence of viruses of yellow dwarfness in barley (BYDV-PAV, BYDV-RMV), of yellow dwarfness in cereals (CYDV-RPV) and dwarfness in wheat (WDV) in stands of winter wheat and winter barley in Slovakia. During the period 2001&ndash;2004 a total of 292 samples coming from 150 localities were analyzed. This involved 190 samples of winter wheat (39 varieties and 13 breeding lines) and 102 samples of winter barley (17 varieties and 7 breeding lines). The detection of viruses was carried out with the aid of the method DAS and TAS ELISA. During the years surveyed, the occurrence of the various viruses differed. In 2001, the most represented virus proved to be the WDV (68%); in 2002, it was the strain PAV of the virus BYDV (93%); in 2003, the most numerous were the virus WDV (71%) and the strain PAV of virus BYDV (67%). Similarly, in 2004, two viruses were represented about evenly, WDV and BYDV-PAV (75%). The more frequent of the two species was the virus BYDV, with the strain BYDV-PAV predominating. The intensity of viral infection of stand cereals differed during the experimental years, being highest in 2002 when the blight occurred both locally and also on a large-scale. The highest frequency of the disease was in Western and Eastern Slovakia.


Plant Disease ◽  
2016 ◽  
Vol 100 (2) ◽  
pp. 276-286 ◽  
Author(s):  
M. Crespo ◽  
F. M. Cazorla ◽  
A. de Vicente ◽  
E. Arrebola ◽  
J. A. Torés ◽  
...  

Mango malformation disease (MMD) has become an important global disease affecting this crop. The aim of this study was to identify the main causal agents of MMD in the Axarquía region of southern Spain and determine their genetic diversity. Fusarium mangiferae was previously described in the Axarquía region but it represented only one-third of the fusaria recovered from malformed trees. In the present work, fusaria associated with MMD were analyzed by arbitrary primed polymerase chain reaction (ap-PCR), random amplified polymorphic DNA (RAPD), vegetative compatibility grouping (VCG), a PCR screen for mating type idiomorph, and phylogenetic analyses of multilocus DNA sequence data to identify and characterize the genetic diversity of the MMD pathogens. These analyses confirmed that 92 of the isolates were F. tupiense, which was previously only known from Brazil and Senegal. In addition, two isolates of a putatively novel MMD pathogen were discovered, nested within the African clade of the Fusarium fujikuroi species complex. The F. tupiense isolates all belonged to VCG I, which was first described in Brazil, and the 11 isolates tested showed pathogenicity on mango seedlings. Including the prior discovery of F. mangiferae, three exotic MMD pathogenic species have been found in southern Spain, which suggests multiple independent introductions of MMD pathogens in the Axarquía region.


2003 ◽  
Vol 93 (11) ◽  
pp. 1386-1392 ◽  
Author(s):  
Boovaraghan Balaji ◽  
Dennis B. Bucholtz ◽  
Joseph M. Anderson

Reliable detection and quantification of barley and cereal yellow dwarf viruses (YDVs) is a critical component in managing yellow dwarf diseases in small grain cereal crops. The method currently used is enzyme-linked immunosorbent assay (ELISA), using antisera against the coat proteins that are specific for each of the various YDVs. Recently, quantitative real-time reverse-transcription polymerase chain reaction (Q-RT-PCR) has been used to detect bacterial and viral pathogens and to study gene expression. We applied this technique to detect and quantify YDVs using primers specific for Barley yellow dwarf virus-PAV (BYDV-PAV) and Cereal yellow dwarf virus-RPV (CYDV-RPV) coat protein genes because of the higher sensitivity of RT-PCR and the advantage of using a real-time PCR instrument. This Q-RT-PCR was used to detect BYDV and CYDV, and to examine disease development in a resistant wheatgrass, a resistant wheat line, a susceptible wheat line, and a susceptible oat line. BYDV-PAV and CYDV-RPV were detected as early as 2 and 6 h, respectively, in susceptible oat compared with detection by ELISA at 4 and 10 days postinoculation. BYDV-PAV RNA accumulated more rapidly and to a higher level than CYDV-RPV RNA in both oat and wheat, which may account for PAV being more prevalent and causing more severe viral disease than CYDV. Q-RT-PCR is reproducible, sensitive, and has the potential to be used for examining yellow dwarf disease and as a rapid diagnostic tool for YDVs.


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