Downy mildew caused by oomycete pathogen
Plasmopara viticola is a devastating disease of grapevine.
P. viticola secretes an array of RXLR effectors to enhance virulence. One of these effectors, PvRXLR131, has been reported to interact with grape (
Vitis vinifera) BRI1 kinase
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Downy mildew caused by oomycete pathogen
Plasmopara viticola is a devastating disease of grapevine.
P. viticola secretes an array of RXLR effectors to enhance virulence. One of these effectors, PvRXLR131, has been reported to interact with grape (
Vitis vinifera) BRI1 kinase inhibitor (VvBKI1). BKI1 is conserved in
Nicotiana benthamiana and
Arabidopsis thaliana. However, the role of VvBKI1 in plant immunity is unknown. Here, we found transient expression of
VvBKI1 in grapevine and
N. benthamiana increased its resistance to
P. viticola and
Phytophthora capsici, respectively. Furthermore, ectopic expression of VvBKI1 in Arabidopsis can increase its resistance to downy mildew caused by
Hyaloperonospora arabidopsidis. Further experiments revealed that VvBKI1 interacts with a cytoplasmic ascorbate peroxidase, VvAPX1, an ROS-scavenging protein. Transient expression of
VvAPX1 in grape and
N. benthamiana promoted its resistance against
P. viticola, and
P. capsici. Moreover,
VvAPX1 transgenic Arabidopsis is more resistant to
H. arabidopsidis. Furthermore, both VvBKI1 and VvAPX1 transgenic Arabidopsis showed an elevated ascorbate peroxidase activity and enhanced disease resistance. In summary, our findings suggest a positive correlation between APX activity and resistance to oomycetes and that this regulatory network is conserved in
V. vinifera,
N. benthamiana, and
A. thaliana.
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