The Magnaporthe oryzae avirulence gene AvrPiz-t encodes a predicted secreted protein that triggers the immunity in rice mediated by the blast resistance gene Piz-t.
The Magnaporthe oryzae avirulence gene AvrPiz-t activates immunity in a gene-for-gene fashion to rice mediated by the blast resistance gene Piz-t. To dissect the molecular mechanism underlying their recognition, we initiated the cloning of AvrPiz-t using a map-based cloning strategy. The AvrPiz-t gene was delimited to an approximately 21-kb genomic fragment, in which six genes were predicted. Complementation tests of each of these six candidate genes led to the final identification of AvrPiz-t, which encodes a 108-amino-acid predicted secreted protein with unknown function and no homologues in M. oryzae or in other sequenced fungi. We found that AvrPiz-t is present in the virulent isolate GUY11 but contains a Pot3 insertion at a position 462 bp upstream from the start codon. Complementation tests of AvrPiz-t genes driven by promoters of varying length revealed that a promoter larger than 462 bp is essential to maintain the AvrPiz-t function. These results suggest that a Pot3 insertion in GUY11 might interfere with the proper function of AvrPiz-t. Additionally, we found that AvrPiz-t can suppress the programmed cell death triggered by mouse BAX protein in Nicotiana benthamiana, identifying a mechanism by which AvrPiz-t may contribute virulence of M. oryzae.
Li
Wei
W
National Center for Gene Research & Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China.
Wang
Baohua
B
Wu
Jun
J
Lu
Guodong
G
Hu
Yajun
Y
Zhang
Xing
X
Zhang
Zhengguang
Z
Zhao
Qiang
Q
Feng
Qi
Q
Zhang
Hongyan
H
Wang
Zhengyi
Z
Wang
Guoliang
G
Han
Bin
B
Wang
Zonghua
Z
Zhou
Bo
B
D022202:Chromosomes, Artificial, Bacterial; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D020082:Magnaporthe / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D012275:Oryza / Q000276:immunology* / Q000382:microbiology; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000276:immunology; D017422:Sequence Analysis, DNA
D004271:DNA, Fungal; D005656:Fungal Proteins; D010940:Plant Proteins