title: Revealing the inventory of type III effectors in Pantoea agglomerans gall-forming pathovars using draft genome sequences and a machine-learning approach.
abstract: Pantoea agglomerans, a widespread epiphytic bacterium, has evolved into a hypersensitive response and pathogenicity (hrp)-dependent and host-specific gall-forming pathogen by the acquisition of a pathogenicity plasmid containing a type III secretion system (T3SS) and its effectors (T3Es). Pantoea agglomerans pv. betae (Pab) elicits galls on beet (Beta vulgaris) and gypsophila (Gypsophila paniculata), whereas P. agglomerans pv. gypsophilae (Pag) incites galls on gypsophila and a hypersensitive response (HR) on beet. Draft genome sequences were generated and employed in combination with a machine-learning approach and a translocation assay into beet roots to identify the pools of T3Es in the two pathovars. The genomes of the sequenced Pab4188 and Pag824-1 strains have a similar size (∼5 MB) and GC content (∼55%). Mutational analysis revealed that, in Pab4188, eight T3Es (HsvB, HsvG, PseB, DspA/E, HopAY1, HopX2, HopAF1 and HrpK) contribute to pathogenicity on beet and gypsophila. In Pag824-1, nine T3Es (HsvG, HsvB, PthG, DspA/E, HopAY1, HopD1, HopX2, HopAF1 and HrpK) contribute to pathogenicity on gypsophila, whereas the PthG effector triggers HR on beet. HsvB, HsvG, PthG and PseB appear to endow pathovar specificities to Pab and Pag, and no homologous T3Es were identified for these proteins in other phytopathogenic bacteria. Conversely, the remaining T3Es contribute to the virulence of both pathovars, and homologous T3Es were found in other phytopathogenic bacteria. Remarkably, HsvG and HsvB, which act as host-specific transcription factors, displayed the largest contribution to disease development.
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel.|Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, Rishon, LeZion, 7528809, Israel.
authors.forename: Gal
authors.initials: G
authors.lastname: Nissan
authors.affiliation: Department of Cell Research and Immunology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Gershovits
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel.|Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, Rishon, LeZion, 7528809, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Morozov
authors.affiliation: Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, Rishon, LeZion, 7528809, Israel.
authors.forename: Laura
authors.initials: L
authors.lastname: Chalupowicz
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel.
authors.forename: Guido
authors.initials: G
authors.lastname: Sessa
authors.affiliation: Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, Rishon, LeZion, 7528809, Israel.
authors.forename: Shulamit
authors.initials: S
authors.lastname: Manulis-Sasson
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel.
authors.forename: Isaac
authors.initials: I
authors.lastname: Barash
authors.affiliation: Department of Cell Research and Immunology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978, Israel.
authors.forename: Tal
authors.initials: T
authors.lastname: Pupko
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D004252:DNA Mutational Analysis; D000069550:Machine Learning; D020636:Pantoea / Q000472:pathogenicity*; D010941:Plant Tumors / Q000382:microbiology*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins
keywords: Pantoea agglomerans pv. betae; Pantoea agglomerans pv. gypsophilae; galls; gypsophila; pathoadaptive; pseB; table beet