Development and validation of recombinant proteins for defence mechanism induction against papaya dieback disease caused by Erwinia mallotivora
Erwinia mallotivora (EM) is a Gram-negative bacterium causing dieback disease of papaya. This disease affects the whole part of the plant, initially changing the colour of the leaves and subsequently leading to wilting and death of the infected plants. Synthetic pesticides and cultural practices...
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| Format: | Thesis |
| Language: | English |
| Published: |
2022
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| Online Access: | http://psasir.upm.edu.my/id/eprint/119408/ http://psasir.upm.edu.my/id/eprint/119408/1/119408.pdf |
| _version_ | 1848867956970225664 |
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| author | Bakar, Ros Azrinawati Hana |
| author_facet | Bakar, Ros Azrinawati Hana |
| author_sort | Bakar, Ros Azrinawati Hana |
| building | UPM Institutional Repository |
| collection | Online Access |
| description | Erwinia mallotivora (EM) is a Gram-negative bacterium causing dieback disease of
papaya. This disease affects the whole part of the plant, initially changing the colour of
the leaves and subsequently leading to wilting and death of the infected plants. Synthetic
pesticides and cultural practices are among the strategies utilised to control the disease
in the field. The adoption of effector proteins in promoting plant defence mechanisms
by inducing specific defence mechanisms responses has been reported to be a promising
control method. This study used harpin protein as the main ingredient in developing the
bio-bactericide. Previous studies showed that harpin proteins could induce systemic
acquired resistance (SAR) in plants and eventually increase the host resistance against
bacterial infections. The plasmid DNA extraction was conducted using the GeneJET
Plasmid Miniprep Kit (Thermo Scientific, USA), according to the manufacturer’s
recommendations. Two selected harpin proteins i.e. Hrp I and Hrp II, were used in this
study to control the disease in glasshouse and field trials. The first objective was to
transform, express, and purify Hrp I and II as SAR inducers in a bacterial system,
Escherichia coli. The results showed that Hrp I and II were successfully transformed,
expressed, and purified, with an estimated proteins size of ~30 and ~ 45 kDa. The second
objective was to assess the effectiveness of Hrp I and II as the SAR inducers at the
glasshouse trial. The results of the foliar application revealed the protection index were
70.8% and 35.7% of Hrp I and Hrp II, respectively. The third objective was to assess the
potential and effectiveness of Hrp I as a SAR inducer in the field trial. The field trial
results demonstrated that a promising protection index of 72.3%. Furthermore, the plant
growth promotion attributes were also observed in the treated plants. Finally, the fourth
objective was to validate the selected defence-related genes by gene expression on the
treated and untreated plants via RT-qPCR analysis. The results indicated that the papaya
plants treated with Hrp I possess the highest expression of gene-related defence like
PRX, OSM, and PR-ID both in the glasshouse and field trials. In conclusion, the adoption
of the Hrp I is a promissing disease control approach in managing papaya dieback disease
under both glasshouse and field conditions |
| first_indexed | 2025-11-15T14:44:44Z |
| format | Thesis |
| id | upm-119408 |
| institution | Universiti Putra Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-15T14:44:44Z |
| publishDate | 2022 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | upm-1194082025-09-02T07:43:30Z http://psasir.upm.edu.my/id/eprint/119408/ Development and validation of recombinant proteins for defence mechanism induction against papaya dieback disease caused by Erwinia mallotivora Bakar, Ros Azrinawati Hana Erwinia mallotivora (EM) is a Gram-negative bacterium causing dieback disease of papaya. This disease affects the whole part of the plant, initially changing the colour of the leaves and subsequently leading to wilting and death of the infected plants. Synthetic pesticides and cultural practices are among the strategies utilised to control the disease in the field. The adoption of effector proteins in promoting plant defence mechanisms by inducing specific defence mechanisms responses has been reported to be a promising control method. This study used harpin protein as the main ingredient in developing the bio-bactericide. Previous studies showed that harpin proteins could induce systemic acquired resistance (SAR) in plants and eventually increase the host resistance against bacterial infections. The plasmid DNA extraction was conducted using the GeneJET Plasmid Miniprep Kit (Thermo Scientific, USA), according to the manufacturer’s recommendations. Two selected harpin proteins i.e. Hrp I and Hrp II, were used in this study to control the disease in glasshouse and field trials. The first objective was to transform, express, and purify Hrp I and II as SAR inducers in a bacterial system, Escherichia coli. The results showed that Hrp I and II were successfully transformed, expressed, and purified, with an estimated proteins size of ~30 and ~ 45 kDa. The second objective was to assess the effectiveness of Hrp I and II as the SAR inducers at the glasshouse trial. The results of the foliar application revealed the protection index were 70.8% and 35.7% of Hrp I and Hrp II, respectively. The third objective was to assess the potential and effectiveness of Hrp I as a SAR inducer in the field trial. The field trial results demonstrated that a promising protection index of 72.3%. Furthermore, the plant growth promotion attributes were also observed in the treated plants. Finally, the fourth objective was to validate the selected defence-related genes by gene expression on the treated and untreated plants via RT-qPCR analysis. The results indicated that the papaya plants treated with Hrp I possess the highest expression of gene-related defence like PRX, OSM, and PR-ID both in the glasshouse and field trials. In conclusion, the adoption of the Hrp I is a promissing disease control approach in managing papaya dieback disease under both glasshouse and field conditions 2022-07 Thesis NonPeerReviewed text en http://psasir.upm.edu.my/id/eprint/119408/1/119408.pdf Bakar, Ros Azrinawati Hana (2022) Development and validation of recombinant proteins for defence mechanism induction against papaya dieback disease caused by Erwinia mallotivora. Doctoral thesis, Universiti Putra Malaysia. http://ethesis.upm.edu.my/id/eprint/18452 Papaya - Diseases Plant diseases - Biological control Erwinia (Bacteria) |
| spellingShingle | Papaya - Diseases Plant diseases - Biological control Erwinia (Bacteria) Bakar, Ros Azrinawati Hana Development and validation of recombinant proteins for defence mechanism induction against papaya dieback disease caused by Erwinia mallotivora |
| title | Development and validation of recombinant proteins for defence mechanism induction against papaya dieback disease caused by Erwinia mallotivora |
| title_full | Development and validation of recombinant proteins for defence mechanism induction against papaya dieback disease caused by Erwinia mallotivora |
| title_fullStr | Development and validation of recombinant proteins for defence mechanism induction against papaya dieback disease caused by Erwinia mallotivora |
| title_full_unstemmed | Development and validation of recombinant proteins for defence mechanism induction against papaya dieback disease caused by Erwinia mallotivora |
| title_short | Development and validation of recombinant proteins for defence mechanism induction against papaya dieback disease caused by Erwinia mallotivora |
| title_sort | development and validation of recombinant proteins for defence mechanism induction against papaya dieback disease caused by erwinia mallotivora |
| topic | Papaya - Diseases Plant diseases - Biological control Erwinia (Bacteria) |
| url | http://psasir.upm.edu.my/id/eprint/119408/ http://psasir.upm.edu.my/id/eprint/119408/ http://psasir.upm.edu.my/id/eprint/119408/1/119408.pdf |