Functional characterization of effector proteins from cacao pathogens and search for their cognate immune receptors

• Grant number: 18/24432-0
• Support type: Research Grants - Young Investigators Grants
• Duration: November 01, 2019 - October 31, 2024
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal researcher: Paulo José Pereira Lima Teixeira
• Grantee: Paulo José Pereira Lima Teixeira
• Home Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Assoc. researchers: Antonio Vargas de Oliveira Figueira ; Gonçalo Amarante Guimarães Pereira ; Jeffery Dangl ; Joseph Ecker ; Lázaro Eustaquio Pereira Peres ; Piotr Andrzej Mieczkowski
• Associated grant(s): 19/27253-2 - Multi-User Equipment approved in grant 2018/24432-0: plant growth chamber, AP.EMU; 19/27255-5 - Multi-User Equipment approved in grant 2018/24432-0: Tecan infinite 200 pro multimode plate reader, AP.EMU
• Associated scholarship(s): 19/27045-0 - Evaluation of the efficiency of virus-induced gene silencing in different Solanaceae species, BP.IC

Abstract

Agriculture is one of the main bases of Brazil's economy, and the country has unique genetic resources that confer an enormous scientific potential that still needs to be explored. Plant diseases caused by microorganisms are among the major problems in agriculture. Like animals, plants have an innate immune system that recognizes and responds to molecules typical of microbes in order to limit the development of potential invaders. However, adapted pathogens modulate plant immunity and metabolism using virulence effector proteins that can physically interact with host proteins. The present project proposes the study of effectors from pathogens that cause two of the most devastating diseases of cacao: witches' broom disease (Moniliophthora perniciosa) and black pod rot (Phytophthora spp.). Witches' broom disease has been studied for decades and a large collection of genome-sequence isolates of the fungus M. perniciosa is available. On the other hand, little is known about the Phytophthora species that infect cacao, especially in Brazil. Thus, this project will study these pathogens in two main fronts: (I) Definition of the effectors complement of Phytophthora spp. that infect cacao in Brazil. For this, a collection of isolates from Brazilian producing regions will be assembled and characterized for their virulence in cacao. Representative isolates will then have their genomes and transcriptomes sequenced to allow the identification and prioritization of effectors that will be targets of future studies. (II) Functional characterization of putative effectors of the fungus M. perniciosa. For this, a set of 78 candidate effectors selected based on genome and transcriptome analyses will be functionally characterized with the goal of dissecting the molecular mechanisms employed by this pathogen to manipulate the immune system of the cacao tree. Plant proteins that are potentially targeted by these effectors will be identified through the construction of a protein-protein interaction network using CrY2H-seq, a new method for the large-scale construction of interactomes. In addition, this project will employ different plant species to search for receptors that can recognize M. perniciosa effectors and, thus, activate a strong defense response that leads to resistance. Since this fungus is also able to infect plants of the Solanaceae family, a collection of wild Solanaceae will be exposed to this pathogen and to its effectors in a screening for resistant varieties. The identification of potential immune receptors that recognize M. perniciosa will support the future development of cacao varieties that are resistant to this important pathogen. Importantly, the strategies developed in this work can be easily applied for the study of other plant-pathogen interactions that are relevant to the Brazilian agriculture. (AU)