The Expansin Gene CsLIEXP1 Is a Direct Target of CsLOB1 in Citrus

Autor(es)

de Souza-Neto, Reinaldo Rodrigues ; da Costa Vasconcelos, Fernanda Nogales ; Teper, Doron ; Barbosa Carvalho, Isis Gabriela ; Takita, Marco Aurelio ; Benedetti, Celso Eduardo ; Wang, Nian ; de Souza, Alessandra Alves

• Tipo de documento: Artigo Científico
• Fonte: PHYTOPATHOLOGY; v. 113, n. 7, p. 12-pg., 2023-07-01.

Resumo

Transcription activator-like effectors are key virulence factors of Xanthomonas. They are secreted into host plant cells and mimic transcription factors inducing the expression of host susceptibility (S) genes. In citrus, CsLOB1 is a direct target of PthA4, the primary effector associated with citrus canker symptoms. CsLOB1 is a transcription factor, and its expression is required for canker symptoms induced by Xanthomonas citri subsp. citri. Several genes are up-regulated by PthA4; however, only CsLOB1 was described as an S gene induced by PthA4. Here, we investigated whether other up-regulated genes could be direct targets of PthA4 or CsLOB1. Seven up-regulated genes by PthA4 were investigated; however, an expansin-coding gene was more induced than CsLOB1. In Nicotiana benthamiana transient expression experiments, we demonstrate that the expansin-coding gene, referred here to as CsLOB1-INDUCED EXPANSIN 1 (CsLIEXP1), is not a direct target of PthA4, but CsLOB1. Interestingly, CsLIEXP1 was induced by CsLOB1 even without the predicted CsLOB1 binding site, which suggested that CsLOB1 has other unknown binding sites. We also investigated the minimum promoter regulated by CsLOB1, and this region and LOB1 domain were conserved among citrus species and relatives, which suggests that the interaction PthA4-CsLOB1-CsLIEXP1 is conserved in citrus species and relatives. This is the first study that experimentally demonstrated a CsLOB1 downstream target and lays the foundation to identify other new targets. In addition, we demonstrated that the CsLIEXP1 is a putative S gene indirectly induced by PthA4, which may serve as the target for genome editing to generate citrus canker-resistant varieties. (AU)

• Processo FAPESP: 17/13885-1 - Uso de CRISPR/Cas9 na edição de genes de suscetibilidade de Citrus sinensis a Xanthomonas citri subsp. Citri
• Beneficiário: Reinaldo Rodrigues de Souza Neto
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 18/21990-2 - Uso de CRISPR/Cas9 na edição de genes de suscetibilidade de Citrus sinensis a Xanthomonas citri subsp. citri
• Beneficiário: Reinaldo Rodrigues de Souza Neto
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 20/04795-1 - Transformação de variedades de laranja doce para estudo funcional e/ou edição de genes visando resistência a doenças bacterianas de citros
• Beneficiário: Isis Gabriela Barbosa Carvalho
• Modalidade de apoio: Bolsas no Brasil - Programa Capacitação - Treinamento Técnico
• Processo FAPESP: 13/10957-0 - Interação Xylella fastidiosa-inseto vetor-planta hospedeira e abordagens para o controle da clorose variegada dos citros e cancro cítrico
• Beneficiário: Alessandra Alves de Souza
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 14/50880-0 - INCT 2014: de genômica comparativa e funcional e melhoramento assistido de citros
• Beneficiário: Marcos Antonio Machado
• Modalidade de apoio: Auxílio à Pesquisa - Temático