title: An engineered innate immune defense protects grapevines from Pierce disease.
abstract: We postulated that a synergistic combination of two innate immune functions, pathogen surface recognition and lysis, in a protein chimera would lead to a robust class of engineered antimicrobial therapeutics for protection against pathogens. In support of our hypothesis, we have engineered such a chimera to protect against the gram-negative Xylella fastidiosa (Xf), which causes diseases in multiple plants of economic importance. Here we report the design and delivery of this chimera to target the Xf subspecies fastidiosa (Xff), which causes Pierce disease in grapevines and poses a great threat to the wine-growing regions of California. One domain of this chimera is an elastase that recognizes and cleaves MopB, a conserved outer membrane protein of Xff. The second domain is a lytic peptide, cecropin B, which targets conserved lipid moieties and creates pores in the Xff outer membrane. A flexible linker joins the recognition and lysis domains, thereby ensuring correct folding of the individual domains and synergistic combination of their functions. The chimera transgene is fused with an amino-terminal signal sequence to facilitate delivery of the chimera to the plant xylem, the site of Xff colonization. We demonstrate that the protein chimera expressed in the xylem is able to directly target Xff, suppress its growth, and significantly decrease the leaf scorching and xylem clogging commonly associated with Pierce disease in grapevines. We believe that similar strategies involving protein chimeras can be developed to protect against many diseases caused by human and plant pathogens.
authors.affiliation: Plant Sciences Department, University of California, Davis, CA 95616, USA.
authors.forename: Abhaya M
authors.initials: AM
authors.lastname: Dandekar
authors.forename: Hossein
authors.initials: H
authors.lastname: Gouran
authors.forename: Ana María
authors.initials: AM
authors.lastname: Ibáñez
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Uratsu
authors.forename: Cecilia B
authors.initials: CB
authors.lastname: Agüero
authors.forename: Sarah
authors.initials: S
authors.lastname: McFarland
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Borhani
authors.forename: Paul A
authors.initials: PA
authors.lastname: Feldstein
authors.forename: George
authors.initials: G
authors.lastname: Bruening
authors.forename: Rafael
authors.initials: R
authors.lastname: Nascimento
authors.forename: Luiz R
authors.initials: LR
authors.lastname: Goulart
authors.forename: Paige E
authors.initials: PE
authors.lastname: Pardington
authors.forename: Anu
authors.initials: A
authors.lastname: Chaudhary
authors.forename: Meghan
authors.initials: M
authors.lastname: Norvell
authors.forename: Edwin
authors.initials: E
authors.lastname: Civerolo
authors.forename: Goutam
authors.initials: G
authors.lastname: Gupta
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000502:physiology; D002140:California; D017343:Genes, Plant; D005818:Genetic Engineering / Q000379:methods; D007113:Immunity, Innate; D019476:Insect Proteins / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D010935:Plant Diseases / Q000276:immunology* / Q000517:prevention & control; D018515:Plant Leaves / Q000378:metabolism; D018521:Plant Physiological Phenomena / Q000276:immunology; D018547:Plant Stems / Q000378:metabolism; D021382:Protein Sorting Signals; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D019076:Transgenes; D027843:Vitis / Q000276:immunology* / Q000382:microbiology*; D044167:Xylella / Q000235:genetics
chemical_list: D001425:Bacterial Outer Membrane Proteins; D019476:Insect Proteins; C417085:MopB protein, Methylococcus; D010455:Peptides; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; C031162:cecropin B protein, Insecta