Arachidonic acid metabolism is involved in the detoxification and recognition of Phytophthora sojae to benzoxazinones.

BACKGROUND

Phytophthora sojae (Kaufmann and Gerdemann), a pathogenic oomycete, causes one of the most destructive soybean diseases, Phytophthora root and stem rot (PRR). Previous studies have shown that benzoxazines (BXs) such as 6-methoxy-benzoxazolin-2-one (MBOA) and benzoxazoline-2-one (BOA) in maize root exudates inhibit the chemotaxis of zoospores, as well as the mycelial growth and pathogenicity of P. sojae. However, the molecular mechanism by which BXs regulate the growth, development and pathogenicity of P. sojae is still not well understood at present.

RESULTS

By analyzing the transcriptome data, it was determined that PsPTGES2 (encoding prostaglandin E synthase 2), PsGST1 (encoding glutathione S transferase), and PsEPHX2 (encoding soluble epoxide hydrolase) in the arachidonic acid (AA) pathway were involved in the response of P. sojae to MBOA and BOA. Polyethylene glycol (PEG)-mediated protoplast transformation was performed to construct silenced transformants of PsPTGES2, PsGST1, and PsEPHX2. Our data demonstrated that PsPTGES2, PsGST1, and PsEPHX2 were involved in mycelial growth, oospore formation, zoospore encystment, cyst germination in P. sojae. PsPTGES2 and PsGST1 were involved in the pathogenicity. The silencing transformants PsPTGES2 and PsGST1 reduced the metabolic ability to AA and the resistance to BOA. Moreover, the zoospores of the silencing transformants PsPTGES2, PsGST1, and PsEPHX2 decreased the chemotaxis to genistein and repellency to BOA.

CONCLUSION

AA metabolism is involved in the growth, development and pathogenicity of P. sojae and the detoxification and recognition of P. sojae to BXs. The study results provide a solid theoretical basis for developing effective strategies to control the infection and pathogenicity of P. sojae. © 2024 Society of Chemical Industry.