Publicação
Potential effect of retrotransposons as determinant factors in the genetic variability and virulence of Hemileia vastatrix
| Resumo: | Coffee leaf rust is a devastating disease caused by Hemileia vastatrix Berkeley & Broome, leading to huge losses in coffee production. Hemileia vastatrix is an obligate biotrophic pathogen from the Pucciniales family, with the urediniosporic life cycle as the only one known in field. Coffee plant breeding strategies have increasingly become a viable alternative for mitigating coffee rust, although the adaptative capacity of the fungus have been overcoming the duration of the coffee restistant genotipes. There are over 55 races/pathotypes of Hemileia vastatrix, therefore it is of great importance to comprehend how genetic variation is promoted, as well as the regulator mechanisms of the differentiated pathogen virulence profiles. Retrotransposons are associated with genome structural variations and gene expression regulation in plant pathogens. These features may be associated to their capacity to rapidly evolve virulence. In this work, the genome size estimation and the genetic variability, concerning nucleotide sequence and copy number, of three selected retrotransposons (R190, R1057 and R2407), as well as the relative expression profiles along the course of the infection process, were investigated among Hemileia vastatrix contrasting pathotypes to assess their putative association with virulence profiles. The measured genome size (789 Mbp) and its intraspecific variation (166 Mbp) suggests a strong genomic dynamic of expansion/contraction episodes. Moreover, the analysis of the retrotransposons DNA sequences and the construction of median-joining haplotype networks revealed a high level of polymorphism and divergence, both between isolates and within the same isolate. The apparent remarkable activity and mutational rate of the retrotransposons studied may represent a determining mechanism for the generation of genetic diversity in a supposedly asexual pathogen such as H. vastatrix. Moreover, the qPCR analysis of two compatible interactions (Hv1427; race II [v5] and Hv70; race XXIV [v2,4,5]), throughout the infection process (compatible interaction with Coffea arabica var. Caturra 19/1 [SH5] and H152/3 [SH2,4,5], respectively). |
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| Autores principais: | Laureano, Alexandre Miguel Ribeiro |
| Assunto: | coffee plant orange rust genetic variability transposable elements expression profiles cafeeiro ferrugem alaranjada variabilidade genética elementos transponíveis perfis de expressão |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Coffee leaf rust is a devastating disease caused by Hemileia vastatrix Berkeley & Broome, leading to huge losses in coffee production. Hemileia vastatrix is an obligate biotrophic pathogen from the Pucciniales family, with the urediniosporic life cycle as the only one known in field. Coffee plant breeding strategies have increasingly become a viable alternative for mitigating coffee rust, although the adaptative capacity of the fungus have been overcoming the duration of the coffee restistant genotipes. There are over 55 races/pathotypes of Hemileia vastatrix, therefore it is of great importance to comprehend how genetic variation is promoted, as well as the regulator mechanisms of the differentiated pathogen virulence profiles. Retrotransposons are associated with genome structural variations and gene expression regulation in plant pathogens. These features may be associated to their capacity to rapidly evolve virulence. In this work, the genome size estimation and the genetic variability, concerning nucleotide sequence and copy number, of three selected retrotransposons (R190, R1057 and R2407), as well as the relative expression profiles along the course of the infection process, were investigated among Hemileia vastatrix contrasting pathotypes to assess their putative association with virulence profiles. The measured genome size (789 Mbp) and its intraspecific variation (166 Mbp) suggests a strong genomic dynamic of expansion/contraction episodes. Moreover, the analysis of the retrotransposons DNA sequences and the construction of median-joining haplotype networks revealed a high level of polymorphism and divergence, both between isolates and within the same isolate. The apparent remarkable activity and mutational rate of the retrotransposons studied may represent a determining mechanism for the generation of genetic diversity in a supposedly asexual pathogen such as H. vastatrix. Moreover, the qPCR analysis of two compatible interactions (Hv1427; race II [v5] and Hv70; race XXIV [v2,4,5]), throughout the infection process (compatible interaction with Coffea arabica var. Caturra 19/1 [SH5] and H152/3 [SH2,4,5], respectively). |
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