Full text
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| Author(s): |
Lucas Nascimento dos Santos
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2025-03-27 |
| Examining board members: |
Alessandra Alves de Souza;
Maxuel de Oliveira Andrade;
Anete Pereira de Souza
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| Advisor: | Alessandra Alves de Souza |
| Abstract | |
The citrus industry, like other sectors of national agriculture, has significant economic and social relevance. However, orange production has been severely threatened by Huanglongbing (HLB), a disease caused by the bacterium Candidatus Liberibacter asiaticus (CLas). Previous studies on citrus-CLas interactions have identified genes associated with HLB susceptibility, including those belonging to the Sieve Element Occlusion (SEO) gene family. These genes encode subunits of P- proteins, which are directly involved in the obstruction of phloem sieve elements, compromising the physiology of photoassimilate translocation. In this context, SEO genes represent promising targets for genomic studies aimed at their characterization within the Rutaceae family. Understanding their functionality allows the elucidation of their physiological roles under different environmental conditions. To enable such functional studies, it is also essential to establish and continuously optimize plant tissue culture protocols, especially in perennial species, due to their long development and evaluation period. This study aimed to characterize the SEO gene family in citrus species with available genome data and establish correlations between the genomic characteristics of HLB-tolerant and susceptible species. Additionally, we proposed optimizations in embryogenic callus genetic transformation protocols, considering their previously reported high efficiency. Structural analysis of SEO genes and their regulatory elements revealed a higher occurrence of these genes in HLB-susceptible species. Furthermore, the identification of cis- elements in their promoters suggests a potential role in the differential regulation of SEO genes in response to CLas infection. Protein interaction network analysis using the AtSEOa and AtSEOb homologous in Arabidopsis indicated strong interactions with proteins previously associated with immune responses, beyond the high co-occurrence of their coding genes in Citrus spp. Optimizations in embryogenic callus genetic transformation protocols enabled the generation of hundreds of transgenic embryos undergoing regeneration, which will be used for functional studies after acclimatization. Additionally, we achieved genome editing induced by the MAD7 nuclease (Cas12a/Cpf1), representing the first report of its activity in citrus (AU) | |
| FAPESP's process: | 22/12483-5 - CRISPR/Cas9 system in Sieve Element Occlusion c (SEOc) gene editing, aiming at obtaining citrus plants tolerant to Huanglongbing (HLB) |
| Grantee: | Lucas Nascimento dos Santos |
| Support Opportunities: | Scholarships in Brazil - Master |