title: The Pseudomonas syringae type III effector HopD1 suppresses effector-triggered immunity, localizes to the endoplasmic reticulum, and targets the Arabidopsis transcription factor NTL9.
abstract: • Pseudomonas syringae type III effectors are known to suppress plant immunity to promote bacterial virulence. However, the activities and targets of these effectors are not well understood. • We used genetic, molecular, and cell biology methods to characterize the activities, localization, and target of the HopD1 type III effector in Arabidopsis. • HopD1 contributes to P. syringae virulence in Arabidopsis and reduces effector-triggered immunity (ETI) responses but not pathogen-associated molecular pattern-triggered immunity (PTI) responses. Plants expressing HopD1 supported increased growth of ETI-inducing P. syringae strains compared with wild-type Arabidopsis. We show that HopD1 interacts with the membrane-tethered Arabidopsis transcription factor NTL9 and demonstrate that this interaction occurs at the endoplasmic reticulum (ER). A P. syringae hopD1 mutant and ETI-inducing P. syringae strains exhibited enhanced growth on Arabidopsis ntl9 mutant plants. Conversely, growth of P. syringae strains was reduced in plants expressing a constitutively active NTL9 derivative, indicating that NTL9 is a positive regulator of plant immunity. Furthermore, HopD1 inhibited the induction of NTL9-regulated genes during ETI but not PTI. • HopD1 contributes to P. syringae virulence in part by targeting NTL9, resulting in the suppression of ETI responses but not PTI responses and the promotion of plant pathogenicity.
authors: Center for Plant Science Innovation, University of Nebraska, Lincoln, NE, 68588-0660, USA.|Department of Plant Pathology, University of Nebraska, Lincoln, NE, 68588-0722, USA.
authors: Anna
authors: A
authors: Block
authors: Center for Plant Science Innovation, University of Nebraska, Lincoln, NE, 68588-0660, USA.|Department of Plant Pathology, University of Nebraska, Lincoln, NE, 68588-0722, USA.
authors: Tania Y
authors: TY
authors: Toruño
authors: Center for Biotechnology, University of Nebraska, Lincoln, NE, 68588-0665, USA.
authors: Christian G
authors: CG
authors: Elowsky
authors: Center for Plant Science Innovation, University of Nebraska, Lincoln, NE, 68588-0660, USA.|School of Biological Sciences, University of Nebraska, Lincoln, NE, 68588-0118, USA.
authors: Chi
authors: C
authors: Zhang
authors: School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
authors: Jens
authors: J
authors: Steinbrenner
authors: School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
authors: Jim
authors: J
authors: Beynon
authors: Center for Plant Science Innovation, University of Nebraska, Lincoln, NE, 68588-0660, USA.|Department of Plant Pathology, University of Nebraska, Lincoln, NE, 68588-0722, USA.
authors: James R
authors: JR
authors: Alfano
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D058947:Bacterial Secretion Systems; D002462:Cell Membrane / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005936:Glucans / Q000378:metabolism; D007113:Immunity, Innate; D057865:Plant Immunity; D011485:Protein Binding; D021381:Protein Transport; D044224:Pseudomonas syringae / Q000254:growth & development / Q000472:pathogenicity*; D051192:Receptors, Pattern Recognition / Q000378:metabolism; D016897:Respiratory Burst; D014157:Transcription Factors / Q000378:metabolism*; D014774:Virulence
chemical_list: D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D005936:Glucans; C531121:NTL9 protein, Arabidopsis; D051192:Receptors, Pattern Recognition; D014157:Transcription Factors; C048306:callose
keywords: bacterial pathogens; plant defense; plant disease; plant immunity; type III effector