XopN-T3SS effector of Xanthomonas axonopodis pv. punicae localizes to the plasma membrane and modulates ROS accumulation events during blight pathogenesis in pomegranate.
Bacterial blight caused by Xanthomonas axonopodis pv. punicae (Xap) is a major disease of pomegranate. Xap secretes effector proteins via type III secretion system (T3SS) to suppress pathogen-associated molecular pattern (PAMP)-triggered plant immunity (PTI). Previously we reported that XopN, a conserved effector of Xap, modulate in planta bacterial growth, and blight disease. In continuation to that here we report the deletion of XopN from Xap caused higher accumulation of reactive oxygen species (ROS) including H2O2and O2-. We quantitatively assessed the higher accumulation of H2O2in pomegranate leaves infiltrated with Xap ΔxopN compared to Xap wild-type. We analysed that 1.5 to 3.3 fold increase in transcript expression of ROS and flg22-inducible genes, namely FRK1, GST1, WRKY29, PR1, PR2 and PR5 in Arabidopsis when challenged with Xap ΔxopN; contrary, the up-regulation of all the genes were compromised when challenged with either Xap wild-type or Xap ΔxopN+xopN. Further, we demonstrated the plasma-membrane based localization of XopN protein both in its natural and experimental hosts. All together, the present study suggested that XopN-T3SS effector of Xap gets localized in the plasma membrane and suppresses ROS-mediated early defense responses during blight pathogenesis in pomegranate.
Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, Pusa Campus, New Delhi, India.
Rishikesh
R
Kumar
Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, Pusa Campus, New Delhi, India.
Madhvi
M
Soni
Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, Pusa Campus, New Delhi, India. Electronic address: mondal_kk@rediffmail.com.
Kalyan K
KK
Mondal
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics; D002462:Cell Membrane / Q000737:chemistry*; D017353:Gene Deletion; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D029561:Lythraceae / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D000069296:Type III Secretion Systems / Q000378:metabolism; D037521:Virulence Factors / Q000032:analysis* / Q000235:genetics; D053532:Xanthomonas axonopodis / Q000378:metabolism*
D001426:Bacterial Proteins; D017382:Reactive Oxygen Species; D000069296:Type III Secretion Systems; D037521:Virulence Factors
Bacterial blight; Effectors; Pomegranate; T3SS; Xanthomonas; XopN