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Tripathi JN, Ntui VO, Tripathi L. Precision genetics tools for genetic improvement of banana. THE PLANT GENOME 2023:e20416. [PMID: 38012108 DOI: 10.1002/tpg2.20416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/22/2023] [Accepted: 11/02/2023] [Indexed: 11/29/2023]
Abstract
Banana is an important food security crop for millions of people in the tropics but it faces challenges from diseases and pests. Traditional breeding methods have limitations, prompting the exploration of precision genetic tools like genetic modification and genome editing. Extensive efforts using transgenic approaches have been made to develop improved banana varieties with resistance to banana Xanthomonas wilt, Fusarium wilt, and nematodes. However, these efforts should be extended for other pests, diseases, and abiotic stresses. The commercialization of transgenic crops still faces continuous challenges with regulatory and public acceptance. Genome editing, particularly CRISPR/Cas, offers precise modifications to the banana genome and has been successfully applied in the improvement of banana. Targeting specific genes can contribute to the development of improved banana varieties with enhanced resistance to various biotic and abiotic constraints. This review discusses recent advances in banana improvement achieved through genetic modification and genome editing.
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Affiliation(s)
| | | | - Leena Tripathi
- International Institute of Tropical Agriculture, Nairobi, Kenya
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van Esse HP, Reuber TL, van der Does D. Genetic modification to improve disease resistance in crops. THE NEW PHYTOLOGIST 2020; 225:70-86. [PMID: 31135961 PMCID: PMC6916320 DOI: 10.1111/nph.15967] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/08/2019] [Indexed: 05/19/2023]
Abstract
Plant pathogens are a significant challenge in agriculture despite our best efforts to combat them. One of the most effective and sustainable ways to manage plant pathogens is to use genetic modification (GM) and genome editing, expanding the breeder's toolkit. For use in the field, these solutions must be efficacious, with no negative effect on plant agronomy, and deployed thoughtfully. They must also not introduce a potential allergen or toxin. Expensive regulation of biotech crops is prohibitive for local solutions. With 11-30% average global yield losses and greater local impacts, tackling plant pathogens is an ethical imperative. We need to increase world food production by at least 60% using the same amount of land, by 2050. The time to act is now and we cannot afford to ignore the new solutions that GM provides to manage plant pathogens.
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Affiliation(s)
- H. Peter van Esse
- 2Blades Foundation1630 Chicago AvenueEvanstonIL 60201USA
- The Sainsbury LaboratoryUniversity of East AngliaNorwich Research ParkNR4 7UHUK
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Merga IF, Tripathi L, Hvoslef-Eide AK, Gebre E. Application of Genetic Engineering for Control of Bacterial Wilt Disease of Enset, Ethiopia's Sustainability Crop. FRONTIERS IN PLANT SCIENCE 2019; 10:133. [PMID: 30863414 PMCID: PMC6399475 DOI: 10.3389/fpls.2019.00133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 01/28/2019] [Indexed: 05/05/2023]
Abstract
Enset (Ensete ventricosum (Welw.) Cheesman) is one of the Ethiopia's indigenous sustainability crops supporting the livelihoods of about 20 million people, mainly in the densely populated South and Southwestern parts of the country. Enset serves as a food security crop for humans, animal feed, and source of fiber for the producers. The production of enset has been constrained by plant pests, diseases, and abiotic factors. Among these constraints, bacterial wilt disease has been the most important limiting factor for enset production since its outbreak five decades ago. There is no known bacterial wilt disease resistant genetic material in the enset genetic pool to transfer this trait to susceptible enset varieties through conventional breeding. Moreover, the absence of effective chemicals against the disease has left farmers without means to combat bacterial wilt for decades. Genetic engineering has been the alternative approach to develop disease resistant plant materials in other crops where traditional breeding tools are ineffective. This review discusses enset cultivation and recent developments addressing the control of bacterial wilt disease in enset and related crops like banana to help design effective strategies.
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Affiliation(s)
- Ibsa Fite Merga
- International Institute of Tropical Agriculture, Nairobi, Kenya
- Norwegian University of Life Sciences, Ås, Norway
- Ethiopian Institute of Agricultural Research, Addis Ababa, Ethiopia
| | - Leena Tripathi
- International Institute of Tropical Agriculture, Nairobi, Kenya
| | | | - Endale Gebre
- Ethiopian Institute of Agricultural Research, Addis Ababa, Ethiopia
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Nakato V, Mahuku G, Coutinho T. Xanthomonas campestris pv. musacearum: a major constraint to banana, plantain and enset production in central and east Africa over the past decade. MOLECULAR PLANT PATHOLOGY 2018; 19:525-536. [PMID: 28677256 PMCID: PMC6638165 DOI: 10.1111/mpp.12578] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 06/27/2017] [Accepted: 06/30/2017] [Indexed: 05/10/2023]
Abstract
TAXONOMY Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Order Xanthomonadales; Family Xanthomonadaceae; Genus Xanthomonas; currently classified as X. campestris pv. musacearum (Xcm). However, fatty acid methyl ester analysis and genetic and genomic evidence suggest that this pathogen is X. vasicola and resides in a separate pathovar. ISOLATION AND DETECTION Xcm can be isolated on yeast extract peptone glucose agar (YPGA), cellobiose cephalexin agar and yeast extract tryptone sucrose agar (YTSA) complemented with 5-fluorouracil, cephalexin and cycloheximide to confer semi-selectivity. Xcm can also be identified using direct antigen coating enzyme-linked immunosorbent assay (DAC-ELISA), species-specific polymerase chain reaction (PCR) using GspDm primers and lateral flow devices that detect latent infections. HOST RANGE Causes Xanthomonas wilt on plants belonging to the Musaceae, primarily banana (Musa acuminata), plantain (M. acuminata × balbisiana) and enset (Ensete ventricosum). DIVERSITY There is a high level of genetic homogeneity within Xcm, although genome sequencing has revealed two major sublineages. SYMPTOMS Yellowing and wilting of leaves, premature fruit ripening and dry rot, bacterial exudate from cut stems. DISTRIBUTION Xcm has only been found in African countries, namely Burundi, Ethiopia, Democratic Republic of the Congo, Kenya, Rwanda, Tanzania and Uganda. ECOLOGY AND EPIDEMIOLOGY Xcm is transmitted by insects, bats, birds and farming implements. Long-distance dispersal of the pathogen is by the transportation of latently infected plants into new areas. MANAGEMENT The management of Xcm has relied on cultural practices that keep the pathogen population at tolerable levels. Biotechnology programmes have been successful in producing resistant banana plants. However, the deployment of such genetic material has not as yet been achieved in farmers' fields, and the sustainability of transgenic resistance remains to be addressed.
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Affiliation(s)
- Valentine Nakato
- Plant PathologyInternational Institute of Tropical AgricultureKampala 7878Uganda
- Department of Microbiology and Plant Pathology, Centre for Microbial Ecology and Genomics (CMEG), Forestry and Agricultural Biotechnology Institute (FABI)University of PretoriaPretoria 0002South Africa
| | - George Mahuku
- Plant PathologyInternational Institute of Tropical AgricultureKampala 7878Uganda
| | - Teresa Coutinho
- Department of Microbiology and Plant Pathology, Centre for Microbial Ecology and Genomics (CMEG), Forestry and Agricultural Biotechnology Institute (FABI)University of PretoriaPretoria 0002South Africa
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Jin Y, Goodman RE, Tetteh AO, Lu M, Tripathi L. Bioinformatics analysis to assess potential risks of allergenicity and toxicity of HRAP and PFLP proteins in genetically modified bananas resistant to Xanthomonas wilt disease. Food Chem Toxicol 2017; 109:81-89. [PMID: 28830835 DOI: 10.1016/j.fct.2017.08.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 08/16/2017] [Accepted: 08/19/2017] [Indexed: 11/17/2022]
Abstract
Banana Xanthomonas wilt (BXW) disease threatens banana production and food security throughout East Africa. Natural resistance is lacking among common cultivars. Genetically modified (GM) bananas resistant to BXW disease were developed by inserting the hypersensitive response-assisting protein (Hrap) or/and the plant ferredoxin-like protein (Pflp) gene(s) from sweet pepper (Capsicum annuum). Several of these GM banana events showed 100% resistance to BXW disease under field conditions in Uganda. The current study evaluated the potential allergenicity and toxicity of the expressed proteins HRAP and PFLP based on evaluation of published information on the history of safe use of the natural source of the proteins as well as established bioinformatics sequence comparison methods to known allergens (www.AllergenOnline.org and NCBI Protein) and toxins (NCBI Protein). The results did not identify potential risks of allergy and toxicity to either HRAP or PFLP proteins expressed in the GM bananas that might suggest potential health risks to humans. We recognize that additional tests including stability of these proteins in pepsin assay, nutrient analysis and possibly an acute rodent toxicity assay may be required by national regulatory authorities.
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Affiliation(s)
- Yuan Jin
- University of Nebraska-Lincoln, Food Allergy Research and Resource Program, 1901 North 21st Street, P.O. Box 886207, Lincoln, NE 68588-6207, USA
| | - Richard E Goodman
- University of Nebraska-Lincoln, Food Allergy Research and Resource Program, 1901 North 21st Street, P.O. Box 886207, Lincoln, NE 68588-6207, USA
| | - Afua O Tetteh
- University of Nebraska-Lincoln, Food Allergy Research and Resource Program, 1901 North 21st Street, P.O. Box 886207, Lincoln, NE 68588-6207, USA
| | - Mei Lu
- University of Nebraska-Lincoln, Food Allergy Research and Resource Program, 1901 North 21st Street, P.O. Box 886207, Lincoln, NE 68588-6207, USA
| | - Leena Tripathi
- International Institute of Tropical Agriculture, P.O. Box 30709, Nairobi, Kenya.
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Blomme G, Dita M, Jacobsen KS, Pérez Vicente L, Molina A, Ocimati W, Poussier S, Prior P. Bacterial Diseases of Bananas and Enset: Current State of Knowledge and Integrated Approaches Toward Sustainable Management. FRONTIERS IN PLANT SCIENCE 2017; 8:1290. [PMID: 28785275 PMCID: PMC5517453 DOI: 10.3389/fpls.2017.01290] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 07/07/2017] [Indexed: 05/22/2023]
Abstract
Bacterial diseases of bananas and enset have not received, until recently, an equal amount of attention compared to other major threats to banana production such as the fungal diseases black leaf streak (Mycosphaerella fijiensis) and Fusarium wilt (Fusarium oxysporum f. sp. cubense). However, bacteria cause significant impacts on bananas globally and management practices are not always well known or adopted by farmers. Bacterial diseases in bananas and enset can be divided into three groups: (1) Ralstonia-associated diseases (Moko/Bugtok disease caused by Ralstonia solanacearum and banana blood disease caused by R. syzygii subsp. celebesensis); (2) Xanthomonas wilt of banana and enset, caused by Xanthomonas campestris pv. musacearum and (3) Erwinia-associated diseases (bacterial head rot or tip-over disease Erwinia carotovora ssp. carotovora and E. chrysanthemi), bacterial rhizome and pseudostem wet rot (Dickeya paradisiaca formerly E. chrysanthemi pv. paradisiaca). Other bacterial diseases of less widespread importance include: bacterial wilt of abaca, Javanese vascular wilt and bacterial fingertip rot (probably caused by Ralstonia spp., unconfirmed). This review describes global distribution, symptoms, pathogenic diversity, epidemiology and the state of the art for sustainable disease management of the major bacterial wilts currently affecting banana and enset.
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Affiliation(s)
- Guy Blomme
- Bioversity InternationalAddis Ababa, Ethiopia
| | - Miguel Dita
- Brazilian Agricultural Research Corporation – Embrapa Cassava and FruitsCruz das Almas, Brazil
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Tripathi L, Atkinson H, Roderick H, Kubiriba J, Tripathi JN. Genetically engineered bananas resistant to Xanthomonas wilt disease and nematodes. Food Energy Secur 2017; 6:37-47. [PMID: 28713567 PMCID: PMC5488630 DOI: 10.1002/fes3.101] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 02/12/2017] [Accepted: 02/16/2017] [Indexed: 11/08/2022] Open
Abstract
Banana is an important staple food crop feeding more than 100 million Africans, but is subject to severe productivity constraints due to a range of pests and diseases. Banana Xanthomonas wilt caused by Xanthomonas campestris pv. musacearum is capable of entirely destroying a plantation while nematodes can cause losses up to 50% and increase susceptibility to other pests and diseases. Development of improved varieties of banana is fundamental in order to tackle these challenges. However, the sterile nature of the crop and the lack of resistance in Musa germplasm make improvement by traditional breeding techniques either impossible or extremely slow. Recent developments using genetic engineering have begun to address these problems. Transgenic banana expressing sweet pepper Hrap and Pflp genes have demonstrated complete resistance against X. campestris pv. musacearum in the field. Transgenic plantains expressing a cysteine proteinase inhibitors and/or synthetic peptide showed enhanced resistance to a mixed species population of nematodes in the field. Here, we review the genetic engineering technologies which have potential to improve agriculture and food security in Africa.
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Affiliation(s)
- Leena Tripathi
- International Institute of Tropical AgricultureNairobiKenya
| | | | | | - Jerome Kubiriba
- National Agricultural Research LaboratoriesPO Box 7084KampalaUganda
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Anderson JA, Gipmans M, Hurst S, Layton R, Nehra N, Pickett J, Shah DM, Souza TLPO, Tripathi L. Emerging Agricultural Biotechnologies for Sustainable Agriculture and Food Security. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:383-393. [PMID: 26785813 DOI: 10.1021/acs.jafc.5b04543] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
As global populations continue to increase, agricultural productivity will be challenged to keep pace without overtaxing important environmental resources. A dynamic and integrated approach will be required to solve global food insecurity and position agriculture on a trajectory toward sustainability. Genetically modified (GM) crops enhanced through modern biotechnology represent an important set of tools that can promote sustainable agriculture and improve food security. Several emerging biotechnology approaches were discussed in a recent symposium organized at the 13th IUPAC International Congress of Pesticide Chemistry meeting in San Francisco, CA, USA. This paper summarizes the innovative research and several of the new and emerging technologies within the field of agricultural biotechnology that were presented during the symposium. This discussion highlights how agricultural biotechnology fits within the context of sustainable agriculture and improved food security and can be used in support of further development and adoption of beneficial GM crops.
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Affiliation(s)
| | - Martijn Gipmans
- BASF Bioscience Research, c/o metanomics GmbH, Tegeler Weg 33, 10589 Berlin, Germany
| | - Susan Hurst
- Arcadia Biosciences, Seattle, Washington 98119, United States
| | | | - Narender Nehra
- Institute for International Crop Improvement, Donald Danforth Plant Science Center , St. Louis, Missouri 63132, United States
| | - John Pickett
- Rothamsted Research, Harpenden, Herts AL5 2JQ, United Kingdom
| | - Dilip M Shah
- Donald Danforth Plant Science Center , St. Louis, Missouri 63132, United States
| | - Thiago Lívio P O Souza
- Embrapa Arroz e Feijão, Rod. GO-462, km 12, Santo Antônio de Goiás, GO 75.375-000, Brazil
| | - Leena Tripathi
- International Institute of Tropical Agriculture (IITA), Nairobi, Kenya
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Tripathi L, Mwaka H, Tripathi JN, Tushemereirwe WK. Expression of sweet pepper Hrap gene in banana enhances resistance to Xanthomonas campestris pv. musacearum. MOLECULAR PLANT PATHOLOGY 2010; 11:721-31. [PMID: 21029318 PMCID: PMC6640263 DOI: 10.1111/j.1364-3703.2010.00639.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Banana Xanthomonas wilt (BXW), caused by the bacterium Xanthomonas campestris pv. musacearum, is the most devastating disease of banana in the Great Lakes region of Africa. The pathogen's rapid spread has threatened the livelihood of millions of Africans who rely on banana fruit for food security and income. The disease is very destructive, infecting all banana varieties, including both East African Highland bananas and exotic types of banana. In the absence of natural host plant resistance among banana cultivars, the constitutive expression of the hypersensitivity response-assisting protein (Hrap) gene from sweet pepper (Capsicum annuum) was evaluated for its ability to confer resistance to BXW. Transgenic lines expressing the Hrap gene under the regulation of the constitutive CaMV35S promoter were generated using embryogenic cell suspensions of two banana cultivars: 'Sukali Ndiizi' and 'Mpologoma'. These lines were characterized by molecular analysis, and were challenged with Xanthomonas campestris pv. musacearum to analyse the efficacy of the Hrap gene against BXW. The majority of transgenic lines (six of eight) expressing Hrap did not show any symptoms of infection after artificial inoculation of potted plants in the screenhouse, whereas control nontransgenic plants showed severe symptoms resulting in complete wilting. This study demonstrates that the constitutive expression of the sweet pepper Hrap gene in banana results in enhanced resistance to BXW. We describe the development of transgenic banana varieties resistant to BXW, which will boost the arsenal available to fight this epidemic disease and save livelihoods in the Great Lakes region of East and Central Africa.
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Affiliation(s)
- Leena Tripathi
- International Institute of Tropical Agriculture, PO Box 7878, Kampala, Uganda National Agriculture Research Organisation, PO Box 7065, Kampala, Uganda.
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Tripathi L, Mwangi M, Abele S, Aritua V, Tushemereirwe WK, Bandyopadhyay R. Xanthomonas Wilt: A Threat to Banana Production in East and Central Africa. PLANT DISEASE 2009; 93:440-451. [PMID: 30764143 DOI: 10.1094/pdis-93-5-0440] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Affiliation(s)
- Leena Tripathi
- International Institute of Tropical Agriculture, Kampala, Uganda
| | - Maina Mwangi
- International Institute of Tropical Agriculture, Kampala, Uganda
| | - Steffen Abele
- International Institute of Tropical Agriculture, Dar Es Salaam, Tanzania
| | - Valentine Aritua
- National Agricultural Research Laboratories, Kawanda, Kampala, Uganda
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Pandey AK, Ger MJ, Huang HE, Yip MK, Zeng J, Feng TY. Expression of the hypersensitive response-assisting protein in Arabidopsis results in harpin-dependent hypersensitive cell death in response to Erwinia carotovora. PLANT MOLECULAR BIOLOGY 2005; 59:771-80. [PMID: 16270229 DOI: 10.1007/s11103-005-1002-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2004] [Accepted: 07/15/2005] [Indexed: 05/05/2023]
Abstract
Active defense mechanisms of plants against pathogens often include a rapid plant cell death known as the hypersensitive cell death (HCD). Hypersensitive response-assisting protein (HRAP) isolated from sweet pepper intensifies the harpin(Pss)-mediated HCD. Here we demonstrate that constitutive expression of the hrap gene in Arabidopsis results in an enhanced disease resistance towards soft rot pathogen, E. carotovora subsp. carotovora. This resistance was due to the induction of HCD since different HCD markers viz. Athsr3, Athsr4, ion leakage, H(2)O(2) and protein kinase were induced. One of the elicitor harpin proteins, HrpN, from Erwinia carotovora subsp. carotovora was able to induce a stronger HCD in hrap-Arabidopsis than non-transgenic controls. To elucidate the role of HrpN, we used E. carotovora subsp. carotovora defective in HrpN production. The hrpN(-) mutant did not induce disease resistance or HCD markers in hrap-Arabidopsis. These results imply that the disease resistance of hrap-Arabidopsis against a virulent pathogen is harpin dependent.
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Affiliation(s)
- Ajay-Kumar Pandey
- Institute of Plant and Microbial Biology, Academia Sinica 115, Taipei, Taiwan
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Peng JL, Bao ZL, Ren HY, Wang JS, Dong HS. Expression of harpin(xoo) in transgenic tobacco induces pathogen defense in the absence of hypersensitive cell death. PHYTOPATHOLOGY 2004; 94:1048-55. [PMID: 18943792 DOI: 10.1094/phyto.2004.94.10.1048] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
ABSTRACT Harpin(Xoo), encoded by the hpaG(Xoo) gene of Xanthomonas oryzae pv. oryzae, is a member of the harpin group of proteins that induce pathogen resistance and hypersensitive cell death (HCD) in plants. We elaborated whether both processes are correlated in hpaG(Xoo)-expressing tobacco (HARTOB) plants, which produced harpin(Xoo) intracellularly. Resistance to fungal, bacterial, and viral pathogens increased in HARTOB, in correlation with the expression of hpaG(Xoo), the gene NPR1 that regulates several resistance pathways, and defense genes GST1, Chia5, PR-1a, and PR-1b that are mediated by different signals. However, reactive oxygen intermediate burst, the expression of HCD marker genes hsr203 and hin1, and cell death did not occur spontaneously in HARTOB, though they did in untransformed and HARTOB plants treated exogenously with harpin(Xoo). Thus, the transgenic expression of harpin(Xoo) confers nonspecific pathogen defense in the absence of HCD.
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Abstract
Generation of transgenic plants exhibiting traits of interest requires the marriage of several technologies including gene transfer, selection and plant regeneration. Variety is the driver for these technologies because of the breadth of plant species requiring modification. A new selectable marker gene, pflp, has been applied to the recovery of orchid plants that exhibit resistance to a major bacterial disease that plagues the orchid industry. pflp as a selection system might be adaptable to many crops.
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Affiliation(s)
- Elizabeth E Hood
- ProdiGene, 101 Gateway Blvd. Suite 100, College Station, TX 77845, USA.
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Liau CH, Lu JC, Prasad V, Hsiao HH, You SJ, Lee JT, Yang NS, Huang HE, Feng TY, Chen WH, Chan MT. The sweet pepper ferredoxin-like protein (pflp) conferred resistance against soft rot disease in Oncidium orchid. Transgenic Res 2003; 12:329-36. [PMID: 12779121 DOI: 10.1023/a:1023343620729] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Genetic engineering to date has not been used to introduce disease resistance genes into the orchid gene pool. The ferredoxin-like protein gene originally isolated from sweet pepper is thought to function as a natural defense against infection due to its antimicrobial properties. Hence it was reasoned that introduction of this gene might produce Oncidium plants resistant to Erwinia carotovora, the causal agent for the soft rot disease. An expression vector containing sweet pepper ferredoxin-like protein (pflp) cDNA, hph and gusA coding sequence was successfully transformed into protocorm-like bodies (PLBs) of Oncidium orchid, using Agrobacterium tumefaciens strain EHA105. A total of 17 independent transgenic orchid lines was obtained, out of which six transgenic lines (beta-glucuronidase (GUS) positive) were randomly selected and confirmed by Southern, northern and western blot analyses. A bioassay was conducted on the transgenic lines. Transgenic plants showed enhanced resistance to E. carotovora, even when the entire plant was challenged with the pathogen. Our results suggest that pflp may be an extremely useful gene for genetic engineering strategies in orchids to confer resistance against soft rot disease.
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Affiliation(s)
- Chia-Hui Liau
- Institute of BioAgricultural Sciences, Academia Sinica, Taiwan 11529, Republic of China
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Ger MJ, Chen CH, Hwang SY, Huang HE, Podile AR, Dayakar BV, Feng TY. Constitutive expression of hrap gene in transgenic tobacco plant enhances resistance against virulent bacterial pathogens by induction of a hypersensitive response. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2002; 15:764-73. [PMID: 12182333 DOI: 10.1094/mpmi.2002.15.8.764] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Hypersensitive response-assisting protein (HRAP) has been previously reported as an amphipathic plant protein isolated from sweet pepper that intensifies the harpin(Pss)-mediated hypersensitive response (HR). The hrap gene has no appreciable similarity to any other known sequences, and its activity can be rapidly induced by incompatible pathogen infection. To assess the function of the hrap gene in plant disease resistance, the CaMV 35S promoter was used to express sweet pepper hrap in transgenic tobacco. Compared with wild-type tobacco, transgenic tobacco plants exhibit more sensitivity to harpin(Pss) and show resistance to virulent pathogens (Pseudomonas syringae pv. tabaci and Erwinia carotovora subsp. carotovora). This disease resistance of transgenic tobacco does not originate from a constitutive HR, because endogenous level of salicylic acid and hsr203J mRNA showed similarities in transgenic and wildtype tobacco under noninfected conditions. However, following a virulent pathogen infection in hrap transgenic tobacco, hsr203J was rapidly induced and a micro-HR necrosis was visualized by trypan blue staining in the infiltration area. Consequently, we suggest that the disease resistance of transgenic plants may result from the induction of a HR by a virulent pathogen infection.
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Affiliation(s)
- Mang-jye Ger
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China
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Ahmad M, Majerczak DR, Pike S, Hoyos ME, Novacky A, Coplin DL. Biological activity of harpin produced by Pantoea stewartii subsp. stewartii. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2001; 14:1223-34. [PMID: 11605962 DOI: 10.1094/mpmi.2001.14.10.1223] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Pantoea stewartii subsp. stewartii causes Stewart's wilt of sweet corn. A hypersensitive response and pathogenicity (Hrp) secretion system is needed to produce water-soaking and wilting symptoms in corn and to cause a hypersensitive response (HR) in tobacco. Sequencing of the hrp cluster revealed a putative harpin gene, hrpN. The product of this gene was overexpressed in Escherichia coli and shown to elicit the HR in tobacco and systemic resistance in radishes. The protein was designated HrpN(Pnss). Like other harpins, it was heat stable and protease sensitive, although it was three- to fourfold less active biologically than Erwinia amylovora harpin. We used antibodies to purified HrpN(Pnss) to verify that hrpN mutants could not produce harpin. This protein was secreted into the culture supernatant and was produced by strains of P. stewartii subsp. indologenes. In order to determine the importance of HrpN(Pnss) in pathogenesis on sweet corn, three hrpN::Tn5 mutants were compared with the wild-type strain with 50% effective dose, disease severity, response time, and growth rate in planta as parameters. In all tests, HrpN(Pnss) was not required for infection, growth, or virulence in corn or endophytic growth in related grasses.
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Affiliation(s)
- M Ahmad
- Department of Plant Pathology, The Ohio State University, Columbus 43210-1087, USA
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