Investigating the role of ParA protein and the SMC system in chromosomal segregation dynamics in Xanthomonas citri subsp. citri

• Grant number: 24/02745-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: March 01, 2025
• End date: February 29, 2028
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Henrique Ferreira
• Grantee: Carolina Crepaldi
• Host Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

Citriculture faces critical challenges related to phytosanitation and production, with greening (HLB) citrus canker diseases being the primary threats today. Citrus canker causes infections that impact the quality and productivity of citrus fruits in general and is caused by the Gram-negative bacterium Xanthomonas citri subsp. citri (X. citri). The disease is currently prevalent in all productive areas of the state of São Paulo, the world's largest producer of sweet oranges. Although measures to contain citrus canker are in place, they are not entirely effective, and the disease persists. In this context, understanding basic molecular processes of the causative bacterium, X. citri, is essential to guide control strategies and identify more effective antimicrobial targets. Moreover, clarifying these mechanisms can provide a foundation for control against other Xanthomonadaceae, which also affect numerous cultivars of agricultural interest, as well as bacteria of clinical relevance. However, knowledge of proliferative processes such as chromosomal segregation remains limited for this group of bacteria. This proposal aims to investigate the chromosomal segregation of X. citri, analyzing the potential segregation roles of the ParA protein (a key component of the conserved ParABS system) and the SMC complex (responsible for chromosome maintenance and organization). It is known that both are involved in chromosomal segregation in model species, but they have not been fully investigated in X. citri. Interactions between ParA and SMC with the ParB protein, another component of ParABS, will also be explored, given ParB's involvement in chromosome segregation in X. citri. The methodological approach will include gene deletion techniques to assess the essentiality of ParA and SMC, and fluorescence co-localization studies to investigate ParA-ParB and SMC-ParB.