Overexpression of Xanthomonas campestris pv. vesicatoria effector AvrBsT in Arabidopsis triggers plant cell death, disease and defense responses.
Recognition of bacterial effector proteins by plant cells is crucial for plant disease and defense response signaling. The Xanthomonas campestris pv. vesicatoria (Xcv) type III effector protein, AvrBsT, is secreted into plant cells from Xcv strain Bv5-4a. Here, we demonstrate that dexamethasone (DEX): avrBsT overexpression triggers cell death signaling in healthy transgenic Arabidopsis plants. AvrBsT overexpression in Arabidopsis also reduced susceptibility to infection with the obligate biotrophic oomycete Hyaloperonospora arabidopsidis. Overexpression of avrBsT significantly induced some defense-related genes in Arabidopsis leaves. A high-throughput in planta proteomics screen identified TCP-1 chaperonin, SEC7-like guanine nucleotide exchange protein and calmodulin-like protein, which were differentially expressed in DEX:avrBsT-overexpression (OX) Arabidopsis plants during Hp. arabidopsidis infection. Treatment with purified GST-tagged AvrBsT proteins distinctly inhibited the growth and sporulation of Hp. arabidopsidis on Arabdiopsis cotyledons. In contrast, DEX:avrBsT-OX plants exhibited enhanced susceptibility to Pseudomonas syringae pv. tomato (Pst) DC3000 infection. Notably, susceptible cell death and enhanced electrolyte leakage were significantly induced in the Pst-infected leaves of DEX:avrBsT-OX plants. Together, these results suggest that Xcv effector AvrBsT overexpression triggers plant cell death, disease and defense signaling leading to both disease and defense responses to microbial pathogens of different lifestyles.
Laboratory of Molecular Plant Pathology, School of Life Sciences and Biotechnology, Korea University, Anam-dong, Sungbuk-ku, Seoul 136-713, Republic of Korea.
In Sun
IS
Hwang
Nak Hyun
NH
Kim
Du Seok
DS
Choi
Byung Kook
BK
Hwang
D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000302:isolation & purification / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D016923:Cell Death; D018548:Cotyledon / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D003907:Dexamethasone / Q000494:pharmacology; D004198:Disease Susceptibility; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D006861:Hydrogen Peroxide / Q000032:analysis / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D009868:Oomycetes / Q000254:growth & development / Q000472:pathogenicity*; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology / Q000469:parasitology; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D044224:Pseudomonas syringae / Q000472:pathogenicity*; D011994:Recombinant Proteins; D015398:Signal Transduction; D016959:Xanthomonas campestris / Q000235:genetics*
D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D011994:Recombinant Proteins; D003907:Dexamethasone; D006861:Hydrogen Peroxide