Novel EIicitin from Pythium oligandrum Confers Disease Resistance against Phytophthora capsici in Solanaceae Plants

The mycoparasite Pythium oligandrum is a nonpathogenic oomycete that can boost plant immune responses.
Elicitins are microbe-associated molecular patterns (MAMPs) specifically
produced by oomycetes that activate plant defense. Here, we identified
a novel elicitin, PoEli8, from P. oligandrum that exhibits immunity-inducing activity in plants. In vitro-purified
PoEli8 induced strong innate immune responses and enhanced resistance
to the oomycete pathogen Phytophthora capsici in Solanaceae plants, including Nicotiana benthamiana, tomato, and pepper. Cell death and reactive oxygen species (ROS)
accumulation triggered by the PoEli8 protein were dependent on the
plant coreceptors receptor-like kinases (RLKs) BAK1 and SOBIR1. Furthermore,
REli from N. benthamiana, a cell surface
receptor-like protein (RLP) was implicated in the perception of PoEli8
in N. benthamiana. These results indicate
the potential value of PoEli8 as a bioactive formula to protect Solanaceae
plants against Phytophthora.