Nep1-like proteins as a target for plant pathogen control

Abstract

The lack of efficient methods to control the major diseases of crops most important to agriculture leads to huge economic losses and seriously threatens global food security. Many of the most important microbial plant pathogens, including bacteria, fungi, and oomycetes, secrete necrosis- and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs), which critically contribute to the virulence and spread of the disease. NLPs are cytotoxic to eudicot plants, as they disturb the plant plasma membrane by binding to specific plant membrane sphingolipid receptors. Their pivotal role in plant infection and broad taxonomic distribution makes NLPs a promising target for the development of novel phytopharmaceutical compounds. To identify compounds that bind to NLPs from the oomycetes Pythium aphanidermatum and Phytophthora parasitica, a library of 587 small molecules, most of which are commercially unavailable, was screened by surface plasmon resonance. Importantly, compounds that exhibited the highest affinity to NLPs were also found to inhibit NLP-mediated necrosis in tobacco leaves and Phytophthora infestans growth on potato leaves. Saturation transfer difference-nuclear magnetic resonance and molecular modelling of the most promising compound, anthranilic acid derivative, confirmed stable binding to the NLP protein, which resulted in decreased necrotic activity and reduced ion leakage from tobacco leaves. We, therefore, confirmed that NLPs are an appealing target for the development of novel phytopharmaceutical agents and strategies, which aim to directly interfere with the function of these major microbial virulence factors. The compounds identified in this study represent lead structures for further optimization and antimicrobial product development.

SsNEP2 Contributes to the Virulence of Sclerotinia sclerotiorum

“…The virulence of S. sclerotiorum is regulated by multiple factors [39]. A key factor is the secretion of proteins out of cells, and the NLP family makes up most of the secreted protein [40]. The results of our assays show that the virulence of the deletion mutant was significantly reduced.…”

Intraspecific Comparative Analysis Reveals Genomic Variation of Didymella arachidicola and Pathogenicity Factors Potentially Related to Lesion Phenotype

“…NLPs are widespread among microbes such as bacteria, fungi, and oomycetes and act as toxin-like virulence factors that induce tissue necrosis [ 106 , 107 ]. Studies have proved that plant pathogens generally expressed multiple NLPs with necrotrophic or hemibiotrophic lifestyles during infection or in the transition from biotrophic to necrotrophic [ 108 , 109 ]. EVM0015380.1 was functionally annotated as a Kpp6 gene, which has been identified for encoding a mitogen-activated protein (MAP) kinase [ 110 ].…”

An oomycete NLP cytolysin forms transient small pores in lipid membranes

“…The relatively small size of the membrane ruptures indicates that the cytotoxic activity of NLPs may provide pathogens with ions and small molecular weight nutrients derived from damaged plant cells, thus enhancing virulence of necrotrophic pathogens. Insights into the molecular mechanisms underlying NLP-induced pore formation will unlock new avenues for developing specific and targeted strategies to inhibit NLP and thus for combating NLP-producing microbial pathogens ( 34 ).…”