Vleeshouwers, V. | bioRxiv Science

bioRxiv2020

RLP/K enrichment sequencing; a novel method to identify receptor-like protein (RLP) and receptor-like kinase (RLK) genes

O_LIThe identification of immune receptors in crop plants is time-consuming but important for disease control. Previously, resistance gene enrichment sequencing (RenSeq) was developed to accelerate mapping of nucleotide-binding domain and leucine-rich repeat containing (NLR) genes. However, resistances mediated by pattern recognition receptors (PRRs) remain less utilised. C_LIO_LIHere, our pipeline shows accelerated mapping of PRRs. Effectoromics leads to precise identification of plants with target PRRs, and subsequent RLP/K enrichment sequencing (RLP/KSeq) leads to detection of informative SNPs that are linked to the trait. C_LIO_LIUsing Phytophthora infestans as a model, we identified Solanum microdontum plants that recognize the apoplastic effectors INF1 or SCR74. RLP/KSeq in a segregating Solanum population confirmed the localization of the INF1 receptor on chromosome 12, and lead to the rapid mapping of the response to SCR74 to chromosome 9. By using markers obtained from RLP/KSeq in conjunction with additional markers, we fine-mapped the SCR74 receptor to a 43-kbp G-LecRK locus. C_LIO_LIOur findings show that RLP/KSeq enables rapid mapping of PRRs and is especially beneficial for crop plants with large and complex genomes. This work will enable the elucidation and characterisation of the non-NLR plant immune receptors and ultimately facilitate informed resistance breeding. C_LI

plant biology↗

bioRxiv2019

Cleavage of a pathogen apoplastic protein by plant subtilases activates immunity

The plant apoplast is a harsh environment in which hydrolytic enzymes, especially proteases, accumulate during pathogen infection. However, the defense functions of most apoplastic proteases remains largely elusive. Here, we show that a newly identified small cysteine-rich secreted protein PC2 from the potato late blight pathogen Phytophthora infestans induces immunity in Solanum plant species only after cleavage by plant apoplastic subtilisin-like proteases, such as tomato P69B. A minimal 61-amino-acid core peptide carrying two key cysteines and widely conserved among most oomycete species is sufficient for PC2 activity. Kazal-like protease inhibitors, such as EPI1 produced by P. infestans can prevent PC2 cleavage and dampen PC2 elicited host immunity. This study reveals that cleavage of pathogen proteins to release immunogenic peptides is an important function of apoplastic proteases but that pathogens interfere with these functions using protease inhibitor effectors.

plant biology↗