The Phytophthora sojae RXLR effector Avh238 destabilizes soybean Type2 GmACSs to suppress ethylene biosynthesis and promote infection

Abstract

Phytophthora pathogens secrete many effector proteins to manipulate host innate immunity. PsAvh238 is a Phytophthora sojae N-terminal Arg-X-Leu-Arg (RXLR) effector, which evolved to escape host recognition by mutating one nucleotide while retaining plant immunity-suppressing activity to enhance infection. However, the molecular basis of the PsAvh238 virulence function remains largely enigmatic.By using coimmunoprecipitation and liquid chromatography-tandem mass spectrometry analysis, we identified the 1-aminocyclopropane-1-carboxylate synthase (ACS) isoforms, the key enzymes in ethylene (ET) biosynthesis, as a host target of PsAvh238.We show that PsAvh238 interacts with soybean ACSs (GmACSs) in vivo and in vitro. By destabilizing Type2 GmACSs, PsAvh238 suppresses Type2 ACS-catalyzed ET biosynthesis and facilitates Phytophthora infection. Silencing of Type2 GmACSs, and inhibition of ET biosynthesis or signaling, increase soybean susceptibility to P. sojae infection, supporting a role for Type2 GmACSs and ET in plant immunity against P. sojae. Moreover, wild-type P. sojae but not the PsAvh238-disrupted mutants, inhibits ET induction and promotes P. sojae infection in soybean.Our results highlight the ET biosynthesis pathway as an essential part in plant immunity against P. sojae and a direct effector target.

Insight Into Function and Subcellular Localization of Plasmopara viticola Putative RxLR Effectors

“…Although effectors may often have redundant function, several individual effectors are keys to the full virulence of pathogen. For example, AVH241 and AVH238 could induce cell death and promote infection of P. sojae in N. benthamiana (Yu et al, 2012;Yang et al, 2017Yang et al, , 2019. Therefore, we hypothesized that 26 effectors might regulate the plant defense responses to contribute to virulence of P. viticola.…”

Corrigendum

“…Since its publication, the authors of Yang et al . () have brought to our attention an error in their article. In Fig.…”

The WY domain in the Phytophthora effector PSR1 is required for infection and RNA silencing suppression activity

“…For example, some effectors have been shown to both directly hijack plant resistance pathways (King et al ., ; Du et al ., ) and exploit plant susceptibility factors (Yang et al ., ; He et al ., ). Other effectors were reported to suppress plant immunity by interfering with general host cellular processes, including endoplasmic reticulum (ER) stress (Jing et al ., ), autophagosome formation (Dagdas et al ., ), epigenetic regulation (Qiao et al ., ; Kong et al ., ; Hou et al ., )), pre‐mRNA splicing machinery (Huang et al ., ) and phytohormone signaling pathways (Boevink et al ., ; Yang et al ., ). These studies revealed that oomycete effectors evolved to target a variety of host regulatory proteins and thereby interfere with the host defense network and potentially other processes to facilitate infection.…”