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Mutiga SK, Orwa P, Nganga EM, Kyallo MM, Rotich F, Gichuhi E, Kimani JM, Mwongera DT, Were VM, Yanoria MJ, Murori R, Mgonja E, Ziyomo C, Wasilwa L, Bachabi F, Ndjiondjop MN, Ouedraogo I, Correll JC, Talbot NJ. Characterization of Blast Resistance in a Diverse Rice Panel from Sub-Saharan Africa. Phytopathology 2023; 113:1278-1288. [PMID: 36802875 DOI: 10.1094/phyto-10-22-0379-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
There is a recent unparalleled increase in demand for rice in sub-Saharan Africa, yet its production is affected by blast disease. Characterization of blast resistance in adapted African rice cultivars can provide important information to guide growers and rice breeders. We used molecular markers for known blast resistance genes (Pi genes; n = 21) to group African rice genotypes (n = 240) into similarity clusters. We then used greenhouse-based assays to challenge representative rice genotypes (n = 56) with African isolates (n = 8) of Magnaporthe oryzae which varied in virulence and genetic lineage. The markers grouped rice cultivars into five blast resistance clusters (BRC) which differed in foliar disease severity. Using stepwise regression, we found that the Pi genes associated with reduced blast severity were Pi50 and Pi65, whereas Pik-p, Piz-t, and Pik were associated with increased susceptibility. All rice genotypes in the most resistant cluster, BRC 4, possessed Pi50 and Pi65, the only genes that were significantly associated with reduced foliar blast severity. Cultivar IRAT109, which contains Piz-t, was resistant against seven African M. oryzae isolates, whereas ARICA 17 was susceptible to eight isolates. The popular Basmati 217 and Basmati 370 were among the most susceptible genotypes. These findings indicate that most tested genes were not effective against African blast pathogen collections. Pyramiding genes in the Pi2/9 multifamily blast resistance cluster on chromosome 6 and Pi65 on chromosome 11 could confer broad-spectrum resistance capabilities. To gain further insights into genomic regions associated with blast resistance, gene mapping could be conducted with resident blast pathogen collections. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Samuel K Mutiga
- Biosciences for Eastern and Central Africa-International Livestock Research Institute, Nairobi, Kenya
- The University of Arkansas System-Division of Agriculture, Fayetteville, AR, U.S.A
| | | | | | - Martina M Kyallo
- Biosciences for Eastern and Central Africa-International Livestock Research Institute, Nairobi, Kenya
| | | | - Emily Gichuhi
- Kenya Agricultural and Livestock Research Organization, Nairobi, Kenya
| | - John M Kimani
- Kenya Agricultural and Livestock Research Organization, Nairobi, Kenya
| | - David T Mwongera
- Kenya Agricultural and Livestock Research Organization, Nairobi, Kenya
| | | | - Mary Jeanie Yanoria
- International Rice Research Institute (IRRI), Los Baños, Laguna, Philippines
| | | | | | - Cathrine Ziyomo
- Biosciences for Eastern and Central Africa-International Livestock Research Institute, Nairobi, Kenya
| | - Lusike Wasilwa
- Kenya Agricultural and Livestock Research Organization, Nairobi, Kenya
| | - Famata Bachabi
- Africa Rice Center (AfricaRice), Station de M'bé, Bouaké, Côte d'Ivoire
| | | | - Ibrahima Ouedraogo
- Institute of Environment and Agricultural Research, Ouagadougou, Burkina Faso
| | - James C Correll
- The University of Arkansas System-Division of Agriculture, Fayetteville, AR, U.S.A
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Nganga EM, Kyallo M, Orwa P, Rotich F, Gichuhi E, Kimani JM, Mwongera D, Waweru B, Sikuku P, Musyimi DM, Mutiga SK, Ziyomo C, Murori R, Wasilwa L, Correll JC, Talbot NJ. Foliar Diseases and the Associated Fungi in Rice Cultivated in Kenya. Plants 2022; 11:plants11091264. [PMID: 35567265 PMCID: PMC9105481 DOI: 10.3390/plants11091264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 11/16/2022]
Abstract
We conducted a survey to assess the occurrence and severity of rice blast and brown spot diseases on popular cultivars grown in the Busia, Kirinyaga, and Kisumu counties of Kenya in 2019. Working with agricultural extension workers within rice production areas, we interviewed farmers (n = 89) regarding their preferred cultivars and their awareness of blast disease, as this was the major focus of our research. We scored the symptoms of blast and brown spot and assessed the lodging, plant height, and maturity of the crops (days after planting). Furthermore, we collected leaf and neck tissues for the assessment of the prevailing fungal populations. We used specific DNA primers to screen for the prevalence of the causal pathogens of blast, Magnaporthe oryzae, and brown spot, Cochliobolus miyabeanus, on asymptomatic and symptomatic leaf samples. We also conducted fungal isolations and PCR-sequencing to identify the fungal species in these tissues. Busia and Kisumu had a higher diversity of cultivars compared to Kirinyaga. The aromatic Pishori (NIBAM 11) was preferred and widely grown for commercial purposes in Kirinyaga, where 86% of Kenyan rice is produced. NIBAM108 (IR2793-80-1) and BW196 (NIBAM 109) were moderately resistant to blast, while NIBAM110 (ITA310) and Vietnam were susceptible. All the cultivars were susceptible to brown spot except for KEH10005 (Arize Tej Gold), a commercial hybrid cultivar. We also identified diverse pathogenic and non-pathogenic fungi, with a high incidence of Nigrospora oryzae, in the rice fields of Kirinyaga. There was a marginal correlation between disease severity/incidence and the occurrence of causal pathogens. This study provides evidence of the need to strengthen pathogen surveillance through retraining agricultural extension agents and to breed for blast and brown spot resistance in popular rice cultivars in Kenya.
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Affiliation(s)
- Everlyne M. Nganga
- Department of Botany, School of Physical and Biological Sciences, Maseno University, Kisumu P.O. Box 3275-40100, Kenya; (E.M.N.); (P.S.); (D.M.M.)
| | - Martina Kyallo
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, ILRI Complex, Old Naivasha Road, Nairobi P.O. Box 30709-00100, Kenya; (M.K.); (B.W.); (C.Z.)
| | - Philemon Orwa
- Department of Water and Agricultural Resource Management, School of Agriculture, University of Embu, Embu P.O. Box 6-60100, Kenya; (P.O.); (F.R.)
| | - Felix Rotich
- Department of Water and Agricultural Resource Management, School of Agriculture, University of Embu, Embu P.O. Box 6-60100, Kenya; (P.O.); (F.R.)
| | - Emily Gichuhi
- Kenya Agricultural and Livestock Research Organization, Kaptagat Road, Loresho, Nairobi P.O. Box 57811-00200, Kenya; (E.G.); (J.M.K.); (D.M.); (L.W.)
| | - John M. Kimani
- Kenya Agricultural and Livestock Research Organization, Kaptagat Road, Loresho, Nairobi P.O. Box 57811-00200, Kenya; (E.G.); (J.M.K.); (D.M.); (L.W.)
| | - David Mwongera
- Kenya Agricultural and Livestock Research Organization, Kaptagat Road, Loresho, Nairobi P.O. Box 57811-00200, Kenya; (E.G.); (J.M.K.); (D.M.); (L.W.)
| | - Bernice Waweru
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, ILRI Complex, Old Naivasha Road, Nairobi P.O. Box 30709-00100, Kenya; (M.K.); (B.W.); (C.Z.)
| | - Phoebe Sikuku
- Department of Botany, School of Physical and Biological Sciences, Maseno University, Kisumu P.O. Box 3275-40100, Kenya; (E.M.N.); (P.S.); (D.M.M.)
| | - David M. Musyimi
- Department of Botany, School of Physical and Biological Sciences, Maseno University, Kisumu P.O. Box 3275-40100, Kenya; (E.M.N.); (P.S.); (D.M.M.)
| | - Samuel K. Mutiga
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, ILRI Complex, Old Naivasha Road, Nairobi P.O. Box 30709-00100, Kenya; (M.K.); (B.W.); (C.Z.)
- Eastern and Southern Region Office, International Rice Research Institute, ILRI Complex, Old Naivasha Road, Nairobi P.O. Box 30709-00100, Kenya;
- Correspondence:
| | - Cathrine Ziyomo
- Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub, ILRI Complex, Old Naivasha Road, Nairobi P.O. Box 30709-00100, Kenya; (M.K.); (B.W.); (C.Z.)
| | - Rosemary Murori
- Department of Entomology and Plant Pathology, Division of Agriculture, The University of Arkansas System, Fayetteville, AR 72701, USA;
| | - Lusike Wasilwa
- Kenya Agricultural and Livestock Research Organization, Kaptagat Road, Loresho, Nairobi P.O. Box 57811-00200, Kenya; (E.G.); (J.M.K.); (D.M.); (L.W.)
| | - James C. Correll
- Eastern and Southern Region Office, International Rice Research Institute, ILRI Complex, Old Naivasha Road, Nairobi P.O. Box 30709-00100, Kenya;
| | - Nicholas J. Talbot
- The Sainsbury Laboratory, Norwich Research Park, University of East Anglia, Norwich NR4 7UH, UK;
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Mutiga SK, Rotich F, Were VM, Kimani JM, Mwongera DT, Mgonja E, Onaga G, Konaté K, Razanaboahirana C, Bigirimana J, Ndayiragije A, Gichuhi E, Yanoria MJ, Otipa M, Wasilwa L, Ouedraogo I, Mitchell T, Wang GL, Correll JC, Talbot NJ. Integrated Strategies for Durable Rice Blast Resistance in Sub-Saharan Africa. Plant Dis 2021; 105:2749-2770. [PMID: 34253045 DOI: 10.1094/pdis-03-21-0593-fe] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Rice is a key food security crop in Africa. The importance of rice has led to increasing country-specific, regional, and multinational efforts to develop germplasm and policy initiatives to boost production for a more food-secure continent. Currently, this critically important cereal crop is predominantly cultivated by small-scale farmers under suboptimal conditions in most parts of sub-Saharan Africa (SSA). Rice blast disease, caused by the fungus Magnaporthe oryzae, represents one of the major biotic constraints to rice production under small-scale farming systems of Africa, and developing durable disease resistance is therefore of critical importance. In this review, we provide an overview of the major advances by a multinational collaborative research effort to enhance sustainable rice production across SSA and how it is affected by advances in regional policy. As part of the multinational effort, we highlight the importance of joint international partnerships in tackling multiple crop production constraints through integrated research and outreach programs. More specifically, we highlight recent progress in establishing international networks for rice blast disease surveillance, farmer engagement, monitoring pathogen virulence spectra, and the establishment of regionally based blast resistance breeding programs. To develop blast-resistant, high yielding rice varieties for Africa, we have established a breeding pipeline that utilizes real-time data of pathogen diversity and virulence spectra, to identify major and minor blast resistance genes for introgression into locally adapted rice cultivars. In addition, the project has developed a package to support sustainable rice production through regular stakeholder engagement, training of agricultural extension officers, and establishment of plant clinics.
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Affiliation(s)
- Samuel K Mutiga
- Biosciences eastern and central Africa - International Livestock Research Institute (BecA-ILRI), Nairobi, Kenya
- Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, AR 72701, U.S.A
| | - Felix Rotich
- Department of Agricultural Resource Management, University of Embu, Embu, Kenya
| | - Vincent M Were
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, U.K
| | - John M Kimani
- Kenya Agricultural and Livestock Research Organization (KALRO), Nairobi, Kenya
| | - David T Mwongera
- Kenya Agricultural and Livestock Research Organization (KALRO), Nairobi, Kenya
| | | | - Geoffrey Onaga
- National Agricultural Research Organization, Kampala, Uganda
| | - Kadougoudiou Konaté
- Institute of Environment and Agricultural Research, Bobo-Dioulasso, Burkina Faso
| | | | | | | | - Emily Gichuhi
- Kenya Agricultural and Livestock Research Organization (KALRO), Nairobi, Kenya
| | | | - Miriam Otipa
- Kenya Agricultural and Livestock Research Organization (KALRO), Nairobi, Kenya
| | - Lusike Wasilwa
- Kenya Agricultural and Livestock Research Organization (KALRO), Nairobi, Kenya
| | - Ibrahima Ouedraogo
- Institute of Environment and Agricultural Research, Bobo-Dioulasso, Burkina Faso
| | - Thomas Mitchell
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
| | - Guo-Liang Wang
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, U.S.A
| | - James C Correll
- Department of Entomology and Plant Pathology, University of Arkansas, Fayetteville, AR 72701, U.S.A
| | - Nicholas J Talbot
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, U.K
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Gawriluk TR, Simkin J, Hacker CK, Kimani JM, Kiama SG, Ezenwa VO, Seifert AW. Complex Tissue Regeneration in Mammals Is Associated With Reduced Inflammatory Cytokines and an Influx of T Cells. Front Immunol 2020; 11:1695. [PMID: 32849592 PMCID: PMC7427103 DOI: 10.3389/fimmu.2020.01695] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/25/2020] [Indexed: 12/12/2022] Open
Abstract
While mammals tend to repair injuries, other adult vertebrates like salamanders and fish regenerate damaged tissue. One prominent hypothesis offered to explain an inability to regenerate complex tissue in mammals is a bias during healing toward strong adaptive immunity and inflammatory responses. Here we directly test this hypothesis by characterizing part of the immune response during regeneration in spiny mice (Acomys cahirinus and Acomys percivali) vs. fibrotic repair in Mus musculus. By directly quantifying cytokines during tissue healing, we found that fibrotic repair was associated with a greater release of pro-inflammatory cytokines (i.e., IL-6, CCL2, and CXCL1) during acute inflammation in the wound microenvironment. However, reducing inflammation via COX-2 inhibition was not sufficient to reduce fibrosis or induce a regenerative response, suggesting that inflammatory strength does not control how an injury heals. Although regeneration was associated with lower concentrations of many inflammatory markers, we measured a comparatively larger influx of T cells into regenerating ear tissue and detected a local increase in the T cell associated cytokines IL-12 and IL-17 during the proliferative phase of regeneration. Taken together, our data demonstrate that a strong adaptive immune response is not antagonistic to regeneration and that other mechanisms likely explain the distribution of regenerative ability in vertebrates.
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Affiliation(s)
- Thomas R. Gawriluk
- Department of Biology, University of Kentucky, Lexington, KY, United States
| | - Jennifer Simkin
- Department of Biology, University of Kentucky, Lexington, KY, United States
| | - Corin K. Hacker
- Department of Biology, University of Kentucky, Lexington, KY, United States
| | - John M. Kimani
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya
| | - Stephen G. Kiama
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya
| | - Vanessa O. Ezenwa
- Odum School of Ecology, University of Georgia, Athens, GA, United States
- Department of Infectious Disease, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Ashley W. Seifert
- Department of Biology, University of Kentucky, Lexington, KY, United States
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya
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Cyr JL, Gawriluk TR, Kimani JM, Rada B, Watford WT, Kiama SG, Seifert AW, Ezenwa VO. Regeneration-Competent and -Incompetent Murids Differ in Neutrophil Quantity and Function. Integr Comp Biol 2020; 59:1138-1149. [PMID: 30989211 DOI: 10.1093/icb/icz023] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Regeneration is rare in mammals, but spiny mice (Acomys spp.) naturally regenerate skin and ear holes. Inflammation is thought to inhibit regeneration during wound healing, but aspects of inflammation contribute to both regeneration and pathogen defense. We compared neutrophil traits among uninjured, regeneration-competent (Acomys: A. cahirinus, A. kempi, A. percivali) and -incompetent (Mus musculus: Swiss Webster, wild-caught strains) murids to test for constitutive differences in neutrophil quantity and function between these groups. Neutrophil quantity differed significantly among species. In blood, Acomys had lower percentages of circulating neutrophils than Mus; and in bone marrow, Acomys had higher percentages of band neutrophils and lower percentages of segmented neutrophils. Functionally, Acomys and Mus neutrophils did not differ in their ability to migrate or produce reactive oxygen species, but Acomys neutrophils phagocytosed more fungal zymosan. Despite this enhanced phagocytosis activity, Acomys neutrophils were not more effective than Mus neutrophils at killing Escherichia coli. Interestingly, whole blood bacteria killing was dominated by serum in Acomys versus neutrophils only or neutrophils and serum in Mus, suggesting that Acomys primarily rely on serum to kill bacteria whereas Mus do not. These subtle differences in neutrophil traits may allow regeneration-competent species to offset damaging effects of inflammation without compromising pathogen defense.
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Affiliation(s)
- Jennifer L Cyr
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Thomas R Gawriluk
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA
| | - John M Kimani
- Department of Veterinary Anatomy and Physiology, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Balázs Rada
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Wendy T Watford
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Stephen G Kiama
- Department of Veterinary Anatomy and Physiology, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Ashley W Seifert
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA.,Department of Veterinary Anatomy and Physiology, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
| | - Vanessa O Ezenwa
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.,Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
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Gawriluk TR, Simkin J, Hacker CK, Kimani JM, Kiama SG, Ezenwa VO, Seifert AW. Complex Tissue Regeneration in Mammals Is Associated With Reduced Inflammatory Cytokines and an Influx of T Cells. Front Immunol 2020. [PMID: 32849592 DOI: 10.3389/fimmu.2020.01695/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2023] Open
Abstract
While mammals tend to repair injuries, other adult vertebrates like salamanders and fish regenerate damaged tissue. One prominent hypothesis offered to explain an inability to regenerate complex tissue in mammals is a bias during healing toward strong adaptive immunity and inflammatory responses. Here we directly test this hypothesis by characterizing part of the immune response during regeneration in spiny mice (Acomys cahirinus and Acomys percivali) vs. fibrotic repair in Mus musculus. By directly quantifying cytokines during tissue healing, we found that fibrotic repair was associated with a greater release of pro-inflammatory cytokines (i.e., IL-6, CCL2, and CXCL1) during acute inflammation in the wound microenvironment. However, reducing inflammation via COX-2 inhibition was not sufficient to reduce fibrosis or induce a regenerative response, suggesting that inflammatory strength does not control how an injury heals. Although regeneration was associated with lower concentrations of many inflammatory markers, we measured a comparatively larger influx of T cells into regenerating ear tissue and detected a local increase in the T cell associated cytokines IL-12 and IL-17 during the proliferative phase of regeneration. Taken together, our data demonstrate that a strong adaptive immune response is not antagonistic to regeneration and that other mechanisms likely explain the distribution of regenerative ability in vertebrates.
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Affiliation(s)
- Thomas R Gawriluk
- Department of Biology, University of Kentucky, Lexington, KY, United States
| | - Jennifer Simkin
- Department of Biology, University of Kentucky, Lexington, KY, United States
| | - Corin K Hacker
- Department of Biology, University of Kentucky, Lexington, KY, United States
| | - John M Kimani
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya
| | - Stephen G Kiama
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya
| | - Vanessa O Ezenwa
- Odum School of Ecology, University of Georgia, Athens, GA, United States.,Department of Infectious Disease, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Ashley W Seifert
- Department of Biology, University of Kentucky, Lexington, KY, United States.,Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya
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