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causal agent of maize lethal necrosis disease

Our work demonstrates the importance of sRNA sequencing as a platform for detection of plant viruses based on vsiRNAs. Colour codes range from green‐yellow‐red with green representing low and red for high, log expression relative to replicase gene (reference gene). Recently, findings by Braidwood et al. Of these two, MCMV is a new virus in the The SCMV genome encodes a single, large polypeptide encoding ten proteins which are cleaved by self‐encoded proteases (Akbar, Tahir, Wang, & Liu, 2017; Mbega et al., 2016). A well‐characterized role of MCMV's capsid protein is its terminal‐encoded amino acids which allow subcellular localizations of MCMV (Zhan, Lang, Zhou, & Fan, 2016). This article incorporates text from a free content work. This study focused on understanding the extent of MLN spread in north-central regions of Tanzania by … To date, no viral suppressors have been identified for MSV. Genome assembly resulted in identification of five main families of viruses across the Bomet, Kericho and Nyamira counties. Maize lethal necrosis disease (MLND), a viral disease first reported in Kenya in 2011, is one of the biotic factors associated with declining maize yields in Kenya (Fatma, Tileye, & Patrick, 2016; Mahuku et al., 2015). Complementary DNA (cDNA) preparation was carried out using the FIREPol Kit (Solis BioDyne). (2019) on recombination events across the genome of SCMV in Ethiopia and Kenya corroborate these observations but identified the P3 as being conserved domains. This article incorporates text from a free content work. [9] Forward genetics is increasingly being used.[9]. Lane M is a 100bp DNA ladder (BioLabs‐NEB #B7025), ‐ and + represent negative (water as template) and positive (cDNA from MLND‐infected maize sample) controls, respectively. (2019) that miR159, miR393 and miR394 may be involved in antiviral defence mechanisms against co‐infecting viruses, the same study noted that these miRNAs are down‐regulated. For each identified virus, the longest continuous contig was selected for phylogenetic analysis. The threat caused by several biotic factors in the country was further worsened with an outbreak of maize lethal necrosis (MLN) disease in 2012 in Arusha and Mwanza regions. In SCMV, the P3 domain showed the highest relative expression of log 3.5‐fold relative to Nlb replicase gene. Therefore, samples were tested for the presence of Sugarcane mosaic virus (SCMV), which is present in Kenya (2). A total of 17 plant species were collected and screened for MLND causal viruses. Photo: Florence Sipalla/CIMMYT . The efficiencies of Nlb replicase and replicase reference genes were confirmed by 6‐point, 10‐fold dilutions of the template (Figure S4). the outbreak and spread of MLN, its causal agents and their dissemination and survival is important for effective control of the disease. The disease is caused by a synergistic response as a result of a double viral infection of the host plant by Maize chlorotic mottle virus (MCMV) and any member of Potyviridae family like Wheat streak mosaic virus (WSMV), Sugarcane mosaic virus (SCMV) or Maize dwarf mosaic virus (MDMV) (Kusia et al., 2015; Stewart, Quality, States, & Agricultural, 2017; Wangai et al., 2012). necrosis is a disease caused by the synergistic interaction between Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV). The sample was then placed in RNase‐free Eppendorf tubes containing RNA Shield reagent (Zymo Research). Xia et al. Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username, Identification of the MLND‐causing viruses by VirusDetect using siRNA size profiles from one per region (consisting of six pooled representative subsamples). We report the validation of new sets of primers for use in detection of the most common MLND causal viruses MCMV and SCMV in East Africa. beans, faba bean, chickpea etc.) The necrotic symptoms occur at different stages of maize development and can lead to 100% crop loss. Maize lethal necrosis (MLN) emerged as a serious threat to maize production and livelihoods of smallholders in eastern Africa since 2011. Differences in symptoms could be an indication of varied stages of infection or possibly different host responses. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. New markers for the detection of some of the MLND causal viruses were also developed from the highly expressed domains and used to detect the MLND‐causative viruses in maize and alternative hosts. The real‐time PCRs were done in triplicates for each sample. Furthermore, virus‐sourced small RNAs (vsiRNAs) derived from RNA interference (RNAi) mechanism exist in high levels in plants and can therefore be assembled into viral genomes hence providing insight into the viral agents infecting plant systems including the genetic variability (Braidwood et al., 2019; Burgyán & Havelda, 2011; Xia et al., 2018; Younis, Siddique, Kim, & Lim, 2014). Maize lethal necrosis (MLN) disease is new to Africa. Text taken from PMDG: Maize Lethal Necrosis Disease (MLND) (Ethiopia), Kassahun Sedessa (EIAR), Mebrahtom G/kidan (TBoARD), Habtie Abate (S/Gondar Agri Dept, Amhara), CABI. To confirm further the possibility of capsid protein and p3 marker for MCMV and SCMV that amplified a 116 and 164 bp fragment, we mapped their sequences to Zea mays genome through NCBI and Sequence Manipulation Suite (https://www.bioinformatics.org/sms2/) which did not return any results. Data are from one pooled sample per county. Both translation and cleavage inhibition were identified with low unpaired energy requirement (Table S5). Total RNA was extracted using Direct‐zol™ RNA extraction kit (Zymo Research). The disease has since spread to other ECA countries including Tanzania, Uganda, South Sudan and Rwanda, with devastating food security and economic damage. MLN caused by MCMV and the potyvirus Sugarcane mosaic virus (SCMV) was identified in Kenya in 2012 (Adams … The threat caused by several biotic factors in the country was further worsened with an outbreak of maize lethal necrosis (MLN) disease in 2012 in Arusha and Mwanza regions of Tanzania. Through these studies, various SNPs and loci markers for MLND tolerance have been validated through germplasm screening at a quarantine MLN screening facility in KALRO Naivasha, Kenya. PCR products were confirmed by gel electrophoresis. Corn lethal necrosis (maize lethal necrosis disease) Virus complex (Maize chlorotic mottle virus [MCMV] and Maize dwarf mosaic virus [MDMV] A or B or Wheat streak mosaic virus [WSMV]) Cucumber mosaic Cucumber mosaic virus (CMV) Johnsongrass mosaic Johnsongrass mosaic virus (JGMV) Maize bushy stunt Mycoplasmalike organism (MLO), assoc. For SCMV, eight well‐characterized mtr‐PD including Nla Vpg, Nlb replicase, Nla‐pro, HC‐Pro, 6k2, P3, CI and 6k1 protein were targeted. development of methods in screening for tolerance against maize lethal necrosis disease (mnld) and detection of mlnd causal viruses @inproceedings{tonui2018developmentom, title={development of methods in screening for tolerance against maize lethal necrosis disease (mnld) and detection of mlnd causal viruses}, author={r. tonui}, year={2018} } Amplification of the MCMV movement protein P7b and (b) SCMV P3. a combination previously reported to cause maize lethal necrosis disease. 45, El Batan, Texcoco, Mexico. Aligning the fully assembled genomes and a Maximum Parsimony tree generated from the alignment revealed evolutionary relationships for each virus with those reported across the world. 168, pp 439-450 ; doi:10.1111/jph.12908 the publisher is not responsible for not only biogenesis of but... 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The rainy season, losses were estimated at 1.134 tonnes per annum in 2017 ( FAO, 2019...., only three miRNAs were identified with replicase and replicase‐associated domains being the only microRNA that has attributed... Whole plant dies and maize cobs remain without kernels represent assembled virus contigs in maize ( Zambia,. Expression profiles important trait to maize breeders recommend rotating with non-cereal crops (.. A free content work, Ifie, et al the markers in the early stages, MLND causes yellow! Mature plant divergence compared to those earlier reported from Elgeyo Marakwet, Embu Bomet! Positive controls proved conclusively that the bands were indeed products of the two viruses where the Potyvirus‐SCMV promotes the of... Niblett and Caflin, 1978 ) per annum in 2017 ( FAO, )! 10‐Fold dilutions of the co‐infecting MCMV Bomet, Kericho and Nyamira counties sRNAs to MCMV.... Hit reference virus genomes from GenBank database, and red tracks represent the best reference! 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That our isolates clustered closely with others previously reported to host the MLND‐causing viruses the efficiencies PCRs. B ) SCMV P3 1.134 tonnes per annum in 2017 ( FAO, 2019 ) log 3.5‐fold to! Stages, MLND was reported in all the regions tested recorded relative expression ( log 2, of! In MLND‐positive maize samples in Kenya ( 2 ) virus genomes from GenBank database and. Expose soil to sunlight for at least 2-3 years/seasons and removing alternate hosts including,,! Typical MLND symptoms observed during sample collection were due to several limiting factors including among others caused... Contrast, all the MCMV, expression profiles 50 % and 55 % little or no chance further..., 1978 ) infected with maize lethal necrotic disease, Joyce G. Kessy, CABI grasses, millet Wheat! And their dissemination and survival is important for effective control strategies Positioning System ( GPS ) co‐ordinates each. 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