Development and evaluation of Swingle rootstocks transformed with the rpfF gene of Xylella fastidiosa

• Grant number: 18/18551-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2018
• End date: December 31, 2019
• Field of knowledge: Biological Sciences - Genetics - Plant Genetics
• Principal Investigator: Alessandra Alves de Souza
• Grantee: Isabella Valderano Santos
• 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: 13/10957-0 - Xylella fastidiosa-vector-host plant interaction and approaches for citrus variegated chlorosis and citrus canker control, AP.TEM

Abstract

The citrus's production is an important crop for Brazilian agribusiness since it is responsible for the majority of the orange juice produced in the world. Although it is a highly competitive market, it is severely affected by diseases that significantly increase the cost of production. Among them, Citrus Variegated Chlorosis (CVC), caused by the bacterium Xylella fastidiosa, is notable for affecting all varieties of sweet orange causing a reduction in fruit size. Citrus canker, caused by the bacterium Xanthomonas citri subsp citri, is another disease that affects plants of this genus, also diminishing the productivity of the orchards, bringing damages to the citrus grower. These phytopathogens present a cluster of genes called rpf (regulator of pathogenicity factors), which is involved in the regulation of pathogenicity factors through a mechanism of intercellular communication, the Quorum Sensing (QS). Using an interference approach in pathogen confusion, plants overexpressing rpfF, responsible for the synthesis of DSF (molecule responsible for the QS of X. fastidiosa and X. citri) were obtained through genetic transformation. The virulence of both bacteria was significantly reduced in transgenic plants. This approach has been showing promising results in varieties of transformed sweet oranges; however the acceptance of transgenic products by the public is still a challenge. In this way, the obtaining of rootstock producing DSF would be interesting so that the molecule could be translocated to non-transgenic scion, increasing its resistance against X. fastidiosa and X. citri.