Editing Citrus sinensis genes to attenuate the accumulation of callose associated with HLB Huanglongbing (HLB) symptoms

• Grant number: 21/03466-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: November 01, 2021
• End date: June 30, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Alessandra Alves de Souza
• Grantee: Dhiôvanna Corrêia Rocha
• Host Institution: Instituto Agronômico (IAC). Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil
• Associated research grant: 20/07045-3 - Biotechnological and genomic strategies for quality, productivity and sustainable management of citrus, coffee and sugar cane in the State of São Paulo, AP.NPOP
• Associated scholarship(s): 23/09068-9 - New technologies for transfection of RNP complex and obtention of commercial varieties of Citrus sinensis with DNA-free genetic editing, BE.EP.DR

Abstract

Sweet orange is one of the Citrus species most affected by Huanglongbing (HLB), a disease caused by the bacterium Candidatus Liberibacter spp. (CLas) which is considered a threat to Citriculture worldwide. As all commercial Citrus species are susceptible to HLB, the development of tolerant varieties has become the biggest challenge for Citriculture. Site-specific gene editing performed using the CRISPR/Cas technique, via plasmid or ribonucleoprotein (RNP), is an innovative approach that can be used to change the responses of plants infected with CLas. Previous work has shown that the expression of genes related to callose deposition (CscalS7 and CscalS12) in phloem are associated with HLB symptoms in more susceptible genotypes. Thus, in this project the genes CscalS7 and CscalS12 will be targets for editing through the CRISPR/Cas techniques by plasmid and RNP, with the objective of developing HLB-tolerant orange trees. The application of these technologies to the study of the citrus-HLB pathosystem will expand the knowledge of the mechanisms involved in the response to HLB and may also contribute to new strategies for seeking tolerance or resistance to be used in susceptible genotypes, in addition to allowing the development of varieties of non-transgenic citrus. (AU)