@article{owati_agindotan_burrows_2020, title={Characterization of Fungal Species Associated with Ascochyta Blight of Dry Pea in Montana and North America and Development of a Differential Medium for Their Detection}, volume={21}, ISSN={["1535-1025"]}, url={https://doi.org/10.1094/PHP-05-20-0037-RS}, DOI={10.1094/PHP-05-20-0037-RS}, abstractNote={Montana leads the production of dry pea in the United States. About 530,000 acres were planted to pea in 2019, accounting for 48% of the total national production ( USDA-NASS 2019 ). A predominant foliar disease of dry pea in Montana is Ascochyta blight, which is caused by multiple fungal pathogens including Didymella pisi, Peyronellaea pinodes, and Peyronellaea pinodella. D. pisi is the predominant pathogen causing Ascochyta blight of dry pea in Montana. Recently, an anticipated shift in pathogen composition has been observed in northeastern Montana from D. pisi to P. pinodes. Also, a Phoma sp. was found associated with infected dry pea seeds and included in this study. To characterize these fungi, we evaluated the effects of temperature (15, 20, 25, and 30°C) on mycelial growth rate and sporulation. The optimum temperature for mycelial growth and sporulation was either 20 or 25°C depending on the species. Analysis of variance supported that at all evaluated temperatures, Phoma sp. had the highest growth rate and produced more spores than the other species (P value < 0.001). In pathogenicity assays, P. pinodes caused more severe disease than the other species when inoculated on pea plants (cv. Carousel, P value ≤ 0.001). The Phoma sp. was not pathogenic. Peameal agar (PMA) was developed as a diagnostic tool for these pathogens. On PMA, the fungal species showed different mycelial morphology, which was used to visually discriminate them. Results from this study will be used as a base to understand the adaptability, pathogenicity and aggressiveness, and current status and changes in the population composition of fungal species causing Ascochyta blight of dry pea in Montana and North America.}, number={4}, journal={PLANT HEALTH PROGRESS}, publisher={Scientific Societies}, author={Owati, Ayodeji and Agindotan, Bright and Burrows, Mary}, year={2020}, pages={262–271} }
 @article{owati_agindotan_burrows_2019, title={Development and Application of Real-Time and Conventional SSR-PCR Assays for Rapid and Sensitive Detection of Didymella pisi Associated with Ascochyta Blight of Dry Pea}, volume={103}, url={https://doi.org/10.1094/PDIS-02-19-0381-RE}, DOI={10.1094/PDIS-02-19-0381-RE}, abstractNote={Didymella pisi is the primary causal pathogen of Ascochyta blight (AB) of dry pea in Montana. Diagnosis of AB is challenging because there are six different species that cause AB worldwide and that can co-occur. Additionally, agar plate identification of D. pisi is challenging due to its slow growth rate. Currently, there are no PCR-based assays developed for specific detection of D. pisi or any fungal pathogen in the AB complex of dry pea. In this study, we evaluated simple sequence repeat (SSR) primer pairs for their specificity and sensitivity in real-time and conventional SSR-PCR both in vitro and in planta. The specificity of the assay was determined by testing DNA of 10 dry pea varieties, fungal species in the AB complex, and fungal species associated with dry pea. To avoid false-negative results, plant and fungal DNA markers were included as controls in a conventional multiplex SSR-PCR, to amplify any plant or fungal DNA in the absence of the D. pisi SSR target. SYBR Green SSR-quantitative PCR (qPCR) detection was conducted using the same primer pairs but in a uniplex format. D. pisi was specifically amplified, whereas other fungi and host DNA were not. Also, sensitivity experiments showed that the detection limit was 0.01 ng of DNA of D. pisi for both assays and 100 conidia in SSR-qPCR. These assays are valuable diagnostic tools for the detection of D. pisi.}, number={11}, journal={Plant Disease}, publisher={Scientific Societies}, author={Owati, Ayodeji and Agindotan, Bright and Burrows, Mary}, year={2019}, month={Nov}, pages={2751–2758} }
 @article{owati_agindotan_burrows_2019, title={First microsatellite markers developed and applied for the genetic diversity study and population structure of Didymella pisi associated with ascochyta blight of dry pea in Montana.}, volume={5}, url={http://europepmc.org/abstract/med/31053327}, DOI={10.1016/j.funbio.2019.02.004}, abstractNote={Didymella pisi is the predominant causal pathogen of ascochyta blight of dry pea causing yield losses in Montana, where 415 000 acres were planted to dry pea in 2018. Thirty-three microsatellite markers were developed for dry pea pathogenic fungus, Didymella pisi, these markers were used to analyze genetic diversity and population structure of 205 isolates from four different geographical regions of Montana. These loci produced a total of 216 alleles with an average of 1.63 alleles per microsatellite marker. The polymorphic information content values ranged from 0.020 to 0.990 with an average of 0.323. The average observed heterozygosity across all loci varied from 0.000 to 0.018. The gene diversity among the loci ranged from 0.003 to 0.461. Unweighted Neighbor-joining and population structure analysis grouped these 205 isolates into two major sub-groups. The clusters did not match the geographic origin of the isolates. Analysis of molecular variance showed 85 % of the total variation within populations and only 15 % among populations. There was moderate genetic variation in the total populations (PhiPT = 0.153). Information obtained from this study could be useful as a base to design strategies for improved management such as breeding for resistance to ascochyta blight of dry pea in Montana.}, journal={Fungal biology}, author={Owati, A and Agindotan, B and Burrows, M}, year={2019}, month={Feb} }
 @article{owati_agindotan_pasche_burrows_2017, title={The Detection and Characterization of QoI-Resistant Didymella rabiei Causing Ascochyta Blight of Chickpea in Montana.}, url={http://europepmc.org/abstract/med/28713416}, DOI={10.3389/fpls.2017.01165}, abstractNote={Ascochyta blight (AB) of pulse crops (chickpea, field pea, and lentils) causes yield loss in Montana, where 1.2 million acres was planted to pulses in 2016. Pyraclostrobin and azoxystrobin, quinone outside inhibitor (QoI) fungicides, have been the choice of farmers for the management of AB in pulses. However, a G143A mutation in the cytochrome b gene has been reported to confer resistance to QoI fungicides. A total of 990 isolates of AB-causing fungi were isolated and screened for QoI resistance. Out of these, 10% were isolated from chickpea, 81% were isolated from field peas, and 9% isolated from lentil. These were from a survey of grower’s fields and seed lots (chickpea = 17, field pea = 131, and lentil = 21) from 23 counties in Montana sent to the Regional Pulse Crop Diagnostic Laboratory, Bozeman, MT, United States for testing. Fungicide-resistant Didymella rabiei isolates were found in one chickpea seed lot each sent from Daniels, McCone and Valley Counties, MT, from seed produced in 2015 and 2016. Multiple alignment analysis of amino acid sequences showed a missense mutation that replaced the codon for amino acid 143 from GGT to GCT, introducing an amino acid change from glycine to alanine (G143A), which is reported to be associated with QoI resistance. Under greenhouse conditions, disease severity was significantly higher on pyraclostrobin-treated chickpea plants inoculated with QoI-resistant isolates of D. rabiei than sensitive isolates (p-value = 0.001). This indicates that where resistant isolates are located, fungicide failures may be observed in the field. D. rabiei-specific polymerase chain reaction primer sets and hydrolysis probes were developed to efficiently discriminate QoI- sensitive and - resistant isolates.}, journal={Frontiers in Plant Science}, author={Owati, AS and Agindotan, B and Pasche, JS and Burrows, M}, year={2017}, month={Jun} }
 @article{lukanda_owati_ogunsanya_valimunzigha_katsongo_ndemere_kumar_2014, title={First Report of Maize chlorotic mottle virus Infecting Maize in the Democratic Republic of the Congo.}, volume={10}, url={http://europepmc.org/abstract/med/30703969}, DOI={10.1094/pdis-05-14-0484-pdn}, abstractNote={Maize (Zea mays L.) is a major food and fodder crop cultivated on 1.54 million ha in the Democratic Republic of the Congo (DRC). In December 2013, unusually severe chlorotic mottle symptoms and pale green streaks were observed in local varieties (Mudishi 1 and 2, Bambou, Kasayi, H614, H613, and Mugamba) and exotic varieties (H520, H624, H403, HDK8031, and ZM607) in Beni, Lubero, and Rutshuru territories at 1,015 to 1,748 m elevation in North Kivu Province. Symptoms were prominent on newly emerging leaves that later developed marginal necrosis resembling the symptoms of maize lethal necrosis (MLN), caused by a dual infection of Maize chlorotic mottle virus (MCMV, genus Machlomovirus) and Sugarcane mosaic virus (SCMV, genus Potyvirus). Each of these viruses, but particularly MCMV, is also known to cause severe mosaic and mottling symptoms in maize (4). In January 2014, symptomatic and asymptomatic samples (n = 20) from disease-affected fields in Beni and Lubero provinces were collected for virus testing using Whatman FTA Classic Cards (1) and analyzed for MCMV (2681F: 5'-ATGAGAGCAGTTGGGGAATGCG and 3226R: 5'-CGAATCTACACACACACACTCCAGC) and SCMV (8679F: 5'-GCAATGTCGAAGAAAATGCG and 9595R: 5'-GTCTCTCACCAAGAGACTCGCAGC) by reverse transcription (RT)-PCR (4). Samples were also analyzed for Maize streak virus (MSV, genus Mastrevirus), an endemic virus in DRC, by PCR using MSV specific primers (MSV215-234: CCAAAKDTCAGCTCCTCCG and MSV1770-1792: TTGGVCCGMVGATGTASAG) (3). A DNA product of expected size (~520 bp) resulted only for MCMV in all the symptomatic plant samples. None of the samples tested positive for SCMV or MSV. RT-PCR analyses were performed to ascertain the absence of potyviruses using the degenerate potyvirus primers (CIFor: 5'GGIVVIGTIGGIWSIGGIAARTCIAC and CIRev: 5'ACICCRTTYTCDATDATRTTIGTIGC3') (2) were also negative. Occurrence of MCMV in symptomatic samples was further confirmed by antigen-coated plate (ACP)-ELISA using anti-MCMV rabbit polyclonal antibodies produced at the Virology Unit, IITA, Ibadan, Nigeria. The RT-PCR product of MCMV was purified and sequenced in both directions (GenBank Accession No. KJ699379). Pairwise comparison of 518 bp nucleotide sequence corresponding to p32 and p37 open reading frames of MCMV by BLASTn search revealed 99.8% nucleotide sequence identity with an MCMV isolate from Kenya (JX286709), 98 to 99% identity with the isolates from China (JQ982468 and KF010583), and 96% identity with the isolates from the United States (X14736 and EU358605). MCMV is a newly emerging virus in Africa, first detected during a severe MLND outbreak in 2011 in Kenya (4). This disease has since become a serious threat to maize production in East Africa. MCMV has been reported in maize from Kenya, Rwanda, Tanzania, and Uganda. To our knowledge, this is the first report of MCMV occurrence in DRC. This finding confirms the further geographic expansion of MCMV and illustrates the need for further studies to identify vectors and also create awareness about the disease and to strengthen surveillance to prevent its further spread in the continent. References: (1) O. J. Alabi et al. J. Virol. Met. 154:111, 2008. (2) C. Ha et al. Arch. Virol. 153:25, 2008. (3) K. E. Palmer and E. P. Rybicki. Arch. Virol. 146:1089, 2001. (4) A. Wangai et al. Plant Dis. 96:1582, 2012.}, journal={Plant disease}, author={Lukanda, M and Owati, A and Ogunsanya, P and Valimunzigha, K and Katsongo, K and Ndemere, H and Kumar, PL}, year={2014}, month={Oct} }
 @article{adegbola_ayodeji_awosusi_atiri_kumar_2013, title={First Report of Banana bunchy top virus in Banana and Plantain (Musa spp.) in Nigeria.}, volume={2}, url={http://europepmc.org/abstract/med/30722330}, DOI={10.1094/pdis-08-12-0745-pdn}, abstractNote={Plantain and banana (Musa spp.) are among the most important staple crops for food and income generation for the rural and urban populations in the humid forest agroecological zone of West Africa. Until recently, Cucumber mosaic virus (genus Cucumovirus) and Banana streak virus (genus Badnavirus) were the only viruses reported to occur in Musa spp. in West Africa. In 2011, an outbreak of banana bunchy top disease (BBTD) caused by Banana bunchy top virus (BBTV; genus Babuvirus, family Nanoviridae) was reported in Ouémé Département (6°30'N and 2°36'E) in the Republic of Benin (2). BBTV is one of the most economically important pathogens of Musa spp. It is well established in Central Africa and also in Angola, Malawi, and Zambia in Southern Africa (2). Plants infected at early growth stages are severely dwarfed and do not bear fruit. BBTV is transmitted by the banana aphid Pentalonia nigronervosa, which is widespread in Africa (1). The regions in the Republic of Benin affected by BBTV border Ogun State (7°00'N and 3°35'E) of Nigeria. Epidemiological investigations were conducted during May 2012 at 31 locations in Ogun State to determine the potential risk of BBTV spreading into Nigeria. Plants with typical symptoms of BBTD (stunting, narrow and shortened leaves, chlorotic streaks on petioles and pseudostem) were observed in four locations: Ilashe, Odan-Itoro, Ido-Ologun, and Igbogila. Total DNA was extracted from 90 leaf samples randomly collected from symptomatic and asymptomatic banana and plantain plants in these areas. Samples were tested for BBTV by polymerase chain reaction (PCR) using primer pairs, mREP-F and mREP-R, which amplifies a 241-bp of BBTV DNA-mRep segment (1), and Scp-F and Scp-R specific for approximately 1075-bp BBTV DNA-S that encodes coat protein gene (1). The amplicons of expected size were obtained from 17 of 90 samples analyzed (18.8%). BBTV in the symptomatic plants was further confirmed by nucleic acid spot hybridization (NASH) assay using DIG-labeled 1,075-bp probe corresponding to coat protein gene and chromogenic detection as per the previously described protocol (3). The DIG-probe specifically reacted with nucleic acid from the symptomatic plants, but not with negative controls, providing conclusive evidence for the BBTV. The PCR products of DNA-mRep segment amplified from three banana plants infected with BBTV collected in Ilashe (Ipokia Local Government Area) were purified and sequenced in both directions. The sequences of these isolates were 100% identical with each other (GenBank Accession Nos. JX290301, JX290302, and JX290303). A BLASTn search revealed 100% nucleotide sequence identity with a BBTV isolate from Benin (JQ437548) and 99 to 100% identity with DNA-mRep sequences of several other BBTV isolates from Africa, Australia, India, and the South Pacific. Further analysis of the 241-bp mRep gene sequences with Neighbor-Joining phylogenetic analysis grouped the BBTV isolate with the South Pacific isolates. To our knowledge, this is the first report of BBTV in Nigeria. This underscores need for surveys to assess the extent of BBTV spread in Nigeria and strict implementation of phytosanitary measures, including restrictions on the movement of planting material from disease-affected regions, to prevent further spread of this important disease. References: (1) P. L. Kumar et al. Virus Res. 159:171, 2011. (2) B. Lokossou et al. New Dis. Rep. 25:13, 2012. (3) W. S. Xie and J. S. Hu. Phytopathol. 85:339, 1995.}, journal={Plant disease}, author={Adegbola, RO and Ayodeji, O and Awosusi, OO and Atiri, GI and Kumar, PL}, year={2013}, month={Feb} }