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postgraduate thesis: Overexpression of rice gene acyl-CoA-binding protein 5 leads to enhanced broad-spectrum pathogen defence in rice and arabidopsis

TitleOverexpression of rice gene acyl-CoA-binding protein 5 leads to enhanced broad-spectrum pathogen defence in rice and arabidopsis
Authors
Advisors
Advisor(s):Chye, MLLo, CSC
Issue Date2018
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
Citation
Panthapulakkal Narayanan, S.. (2018). Overexpression of rice gene acyl-CoA-binding protein 5 leads to enhanced broad-spectrum pathogen defence in rice and arabidopsis. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR.
AbstractPlants are continuously infected by various pathogens throughout their lifespan. Phytopathogens are broadly classified into biotrophs, hemibiotrophs and necrotrophs, among which necrotrophs render a more damaging effect on host plants. Early investigations showed that the expression of Class III acyl-CoA binding proteins (ACBPs), AtACBP3 and OsACBP5, were induced by pathogen infection. Although transgenic Arabidopsis AtACBP3-overexpressors (AtACBP3-OEs) displayed enhanced protection against the bacterial biotroph, Pseudomonas syringae, they were ineffective in defending the fungal necrotroph Botrytis cinerea. This study aims to address the efficiency of an ACBP from monocot, OsACBP5, in conferring resistance to monocots and dicots against all three classes of phytopathogens (biotrophs, hemibiotrophs and necrotrophs). Electrophoretic mobility shift assays identified two pathogen-responsive W-boxes in the OsACBP5 5'-flanking region which binds pathogen-infected rice nuclear proteins, providing a molecular basis for pathogen-inducible regulation of OsACBP5 expression, indicating its potential role in plant defence. To determine the role of OsACBP5 in plant defence, experiments were initially conducted on the model plant Arabidopsis thaliana. When pathogen assays were performed in wild-type (WT), vector-transformed control (VC) and Arabidopsis OsACBP5-OEs using fungal necrotrophs (Rhizoctonia solani, B. cinerea, Alternaria brassicicola), hemibiotrophic fungus (Colletotrichum siamense) and bacterial biotroph (P. syringae), OsACBP5-OEs conferred better resistance against all tested pathogens than the controls. Proteomic analysis on R. solani-infected OsACBP5-OEs revealed an upregulation of cell wall-related proteins, proteins associated with glucosinolate (GSL) degradation and a protein involved in jasmonate (JA) biosynthesis. GSL degradation products facilitated reactive oxygen species production resulting in salicylic acid (SA)-mediated defence responses. These results suggested that the defence mechanism of Arabidopsis OsACBP5-OEs may involve both SA- and JA-mediated signalling pathways. To study the role of OsACBP5 in monocots, experiments were conducted by generating transgenic rice OsACBP5-OEs. When pathogen assays were performed on WT, VC and rice OsACBP5-OEs using fungal necrotrophs (R. solani, Cercospora oryzae), hemibiotrophs (Magnaporthe grisea, Fusarium graminearum) and bacterial biotroph (Xanthamonas oryzae pv. oryzae (Xoo)), OsACBP5-OEs conferred better resistance against all tested pathogens than the controls. GC-MS analysis indicated higher SA and JA contents in OsACBP5-OEs than the controls. Transcriptomic analysis on R. solani-infected OsACBP5-OEs showed an upregulation of genes associated with pattern- and effector-triggered immunity, as well as genes related to SA- and JA-mediated signalling pathways. Transgenic rice OsACBP5-OE9osnpr1 and OsACBP5-OE9oscoi1 were generated by crossing OsACBP5-OE9 with an SA signalling-deficient mutant (osnpr1) and a JA signalling-deficient mutant (oscoi1), respectively, and subsequently infected with R. solani, M. grisea and Xoo. Results from these pathogen assays showed that OsACBP5-OE9osnpr1 was more susceptible to M. grisea and Xoo, whereas, OsACBP5-OE9oscoi1 was more susceptible to R. solani. Hence, enhanced resistance of rice OsACBP5-OEs against necrotrophs appeared to be JA-dependent and (hemi)biotrophs SA-dependent. To explore the application of OsACBP5 in fungal protection could be extended to dicot crops, experiments were conducted by generating transgenic Brassica OsACBP5-OEs. When WT, VC and Brassica OsACBP5-OEs were infected with the necrotroph A. brassicae, OsACBP5-OEs were conferred better protection than the controls. Taken together, the results suggest that OsACBP5 can be used for overexpression in monocots as well as dicots to protect against phytopathogens via SA-and JA-signalling pathways.
DegreeDoctor of Philosophy
SubjectGenetics - Rice
Arabidopsis - Genetics
Dept/ProgramBiological Sciences
Persistent Identifierhttp://hdl.handle.net/10722/269862

 

DC FieldValueLanguage
dc.contributor.advisorChye, ML-
dc.contributor.advisorLo, CSC-
dc.contributor.authorPanthapulakkal Narayanan, Saritha-
dc.date.accessioned2019-05-07T01:50:55Z-
dc.date.available2019-05-07T01:50:55Z-
dc.date.issued2018-
dc.identifier.citationPanthapulakkal Narayanan, S.. (2018). Overexpression of rice gene acyl-CoA-binding protein 5 leads to enhanced broad-spectrum pathogen defence in rice and arabidopsis. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR.-
dc.identifier.urihttp://hdl.handle.net/10722/269862-
dc.description.abstractPlants are continuously infected by various pathogens throughout their lifespan. Phytopathogens are broadly classified into biotrophs, hemibiotrophs and necrotrophs, among which necrotrophs render a more damaging effect on host plants. Early investigations showed that the expression of Class III acyl-CoA binding proteins (ACBPs), AtACBP3 and OsACBP5, were induced by pathogen infection. Although transgenic Arabidopsis AtACBP3-overexpressors (AtACBP3-OEs) displayed enhanced protection against the bacterial biotroph, Pseudomonas syringae, they were ineffective in defending the fungal necrotroph Botrytis cinerea. This study aims to address the efficiency of an ACBP from monocot, OsACBP5, in conferring resistance to monocots and dicots against all three classes of phytopathogens (biotrophs, hemibiotrophs and necrotrophs). Electrophoretic mobility shift assays identified two pathogen-responsive W-boxes in the OsACBP5 5'-flanking region which binds pathogen-infected rice nuclear proteins, providing a molecular basis for pathogen-inducible regulation of OsACBP5 expression, indicating its potential role in plant defence. To determine the role of OsACBP5 in plant defence, experiments were initially conducted on the model plant Arabidopsis thaliana. When pathogen assays were performed in wild-type (WT), vector-transformed control (VC) and Arabidopsis OsACBP5-OEs using fungal necrotrophs (Rhizoctonia solani, B. cinerea, Alternaria brassicicola), hemibiotrophic fungus (Colletotrichum siamense) and bacterial biotroph (P. syringae), OsACBP5-OEs conferred better resistance against all tested pathogens than the controls. Proteomic analysis on R. solani-infected OsACBP5-OEs revealed an upregulation of cell wall-related proteins, proteins associated with glucosinolate (GSL) degradation and a protein involved in jasmonate (JA) biosynthesis. GSL degradation products facilitated reactive oxygen species production resulting in salicylic acid (SA)-mediated defence responses. These results suggested that the defence mechanism of Arabidopsis OsACBP5-OEs may involve both SA- and JA-mediated signalling pathways. To study the role of OsACBP5 in monocots, experiments were conducted by generating transgenic rice OsACBP5-OEs. When pathogen assays were performed on WT, VC and rice OsACBP5-OEs using fungal necrotrophs (R. solani, Cercospora oryzae), hemibiotrophs (Magnaporthe grisea, Fusarium graminearum) and bacterial biotroph (Xanthamonas oryzae pv. oryzae (Xoo)), OsACBP5-OEs conferred better resistance against all tested pathogens than the controls. GC-MS analysis indicated higher SA and JA contents in OsACBP5-OEs than the controls. Transcriptomic analysis on R. solani-infected OsACBP5-OEs showed an upregulation of genes associated with pattern- and effector-triggered immunity, as well as genes related to SA- and JA-mediated signalling pathways. Transgenic rice OsACBP5-OE9osnpr1 and OsACBP5-OE9oscoi1 were generated by crossing OsACBP5-OE9 with an SA signalling-deficient mutant (osnpr1) and a JA signalling-deficient mutant (oscoi1), respectively, and subsequently infected with R. solani, M. grisea and Xoo. Results from these pathogen assays showed that OsACBP5-OE9osnpr1 was more susceptible to M. grisea and Xoo, whereas, OsACBP5-OE9oscoi1 was more susceptible to R. solani. Hence, enhanced resistance of rice OsACBP5-OEs against necrotrophs appeared to be JA-dependent and (hemi)biotrophs SA-dependent. To explore the application of OsACBP5 in fungal protection could be extended to dicot crops, experiments were conducted by generating transgenic Brassica OsACBP5-OEs. When WT, VC and Brassica OsACBP5-OEs were infected with the necrotroph A. brassicae, OsACBP5-OEs were conferred better protection than the controls. Taken together, the results suggest that OsACBP5 can be used for overexpression in monocots as well as dicots to protect against phytopathogens via SA-and JA-signalling pathways.-
dc.languageeng-
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)-
dc.relation.ispartofHKU Theses Online (HKUTO)-
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.-
dc.rightsThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.-
dc.subject.lcshGenetics - Rice-
dc.subject.lcshArabidopsis - Genetics-
dc.titleOverexpression of rice gene acyl-CoA-binding protein 5 leads to enhanced broad-spectrum pathogen defence in rice and arabidopsis-
dc.typePG_Thesis-
dc.description.thesisnameDoctor of Philosophy-
dc.description.thesislevelDoctoral-
dc.description.thesisdisciplineBiological Sciences-
dc.description.naturepublished_or_final_version-
dc.date.hkucongregation2019-
dc.identifier.mmsid991044081524603414-

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