Hexanoic acid, an alternative to copper to protect citrus plants against Xanthomonas citri

• Grant number: 18/23297-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2019
• End date: January 31, 2020
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Henrique Ferreira
• Grantee: Mario Nicolas Caccalano
• Host Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil
• Associated research grant: 15/50162-2 - Protecting plants with antimicrobial peptides and gallates - Pro-Planta, AP.TEM

Abstract

Brazil is the world leader in sweet orange production. Most of this production is destined to the orange juice market, which represents 80% of the juice that is exported in the world. Despite the great success, Brazilian citriculture faces constant threats, especially concerning diseases such as Asiatic Citrus Canker (ACC). ACC is caused by the Gram-negative bacterium Xanthomonas citri subsp. citri (X. citri), which affects all the commercially important citrus varieties and cannot be cured. The incidence of ACC in the state of São Paulo, the biggest Brazilian producer of oranges, has reached 63.14% in some areas. According to the new legislation for the control of ACC, São Paulo is an area of risk mitigation system (SMR); therefore, control of ACC is exerted by the plantation of less susceptible cultivars of citrus, the installation of windbreaks, considering that X. citri is transmitted from plant-to-plant by the combined action of rain and wind, and regular sprays of copper formulations. Copper can be bio-cumulative and it is a toxic metal. Moreover, resistance to copper was already documented in isolates of X. citri. In order to minimize this problem, we intend to evaluate hexanoic acid as an alternative to copper in citrus plant protection. Hexanoic acid has been tested and it is apparently effective against X. citri, however, there is no report about possible mechanisms of action. Using well-established assays, developed by our group, we intend to verify if Hexanoic acid can perturb cellular processes such as cell division, chromosome organization, and disruption of membrane dynamics/permeabilization of X. citri.