title: Enhanced resistance in Theobroma cacao against oomycete and fungal pathogens by secretion of phosphatidylinositol-3-phosphate-binding proteins.
abstract: The internalization of some oomycete and fungal pathogen effectors into host plant cells has been reported to be blocked by proteins that bind to the effectors' cell entry receptor, phosphatidylinositol-3-phosphate (PI3P). This finding suggested a novel strategy for disease control by engineering plants to secrete PI3P-binding proteins. In this study, we tested this strategy using the chocolate tree Theobroma cacao. Transient expression and secretion of four different PI3P-binding proteins in detached leaves of T. cacao greatly reduced infection by two oomycete pathogens, Phytophthora tropicalis and Phytophthora palmivora, which cause black pod disease. Lesion size and pathogen growth were reduced by up to 85%. Resistance was not conferred by proteins lacking a secretory leader, by proteins with mutations in their PI3P-binding site, or by a secreted PI4P-binding protein. Stably transformed, transgenic T. cacao plants expressing two different PI3P-binding proteins showed substantially enhanced resistance to both P. tropicalis and P. palmivora, as well as to the fungal pathogen Colletotrichum theobromicola. These results demonstrate that secretion of PI3P-binding proteins is an effective way to increase disease resistance in T. cacao, and potentially in other plants, against a broad spectrum of pathogens.
authors.affiliation: Department of Plant Science and Huck Institute of Life Sciences, The Pennsylvania State University, University Park, PA, USA.|Center for Genome Research and Biocomputing, and Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA.
authors.forename: Emily E
authors.initials: EE
authors.lastname: Helliwell
authors.affiliation: Virginia Bioinformatics Institute and Department of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
authors.forename: Julio
authors.initials: J
authors.lastname: Vega-Arreguín
authors.affiliation: Department of Plant Science and Huck Institute of Life Sciences, The Pennsylvania State University, University Park, PA, USA.
authors.forename: Zi
authors.initials: Z
authors.lastname: Shi
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Beltsville, MD, USA.
authors.forename: Bryan
authors.initials: B
authors.lastname: Bailey
authors.affiliation: Institute for Bioscience and Biotechnology Research & Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, USA.
authors.forename: Shunyuan
authors.initials: S
authors.lastname: Xiao
authors.affiliation: Department of Plant Science and Huck Institute of Life Sciences, The Pennsylvania State University, University Park, PA, USA.
authors.forename: Siela N
authors.initials: SN
authors.lastname: Maximova
authors.affiliation: Center for Genome Research and Biocomputing, and Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA.|Virginia Bioinformatics Institute and Department of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
authors.forename: Brett M
authors.initials: BM
authors.lastname: Tyler
authors.affiliation: Department of Plant Science and Huck Institute of Life Sciences, The Pennsylvania State University, University Park, PA, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Guiltinan
mesh_terms: D000595:Amino Acid Sequence; D002099:Cacao / Q000235:genetics / Q000382:microbiology*; D020231:Colletotrichum / Q000502:physiology*; D060467:Disease Resistance; D018506:Gene Expression Regulation, Plant; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D028044:Phosphate-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D010838:Phytophthora / Q000472:pathogenicity / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D030821:Plants, Genetically Modified; D000072417:Protein Domains; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D014170:Transformation, Genetic
chemical_list: D050505:Mutant Proteins; D028044:Phosphate-Binding Proteins; D018129:Phosphatidylinositol Phosphates; D010940:Plant Proteins; D012333:RNA, Messenger; C055525:phosphatidylinositol 3-phosphate
keywords: Theobroma cacao; disease resistance; effectors; fungi; oomycetes; phosphatidylinositol-3-phosphate-binding protein