Enzyme‐driven metabolomic screening: a proof‐of‐principle method for discovery of plant defence compounds targeted by pathogens

Abstract

Plants produce a variety of secondary metabolites to defend themselves from pathogen attack, while pathogens have evolved to overcome plant defences by producing enzymes that degrade or modify these defence compounds. However, many compounds targeted by pathogen enzymes currently remain enigmatic. Identifying host compounds targeted by pathogen enzymes would enable us to understand the potential importance of such compounds in plant defence and modify them to make them insensitive to pathogen enzymes. Here, a proof of concept metabolomics-based method was developed to discover plant defence compounds modified by pathogens using two pathogen enzymes with known targets in wheat and tomato. Plant extracts treated with purified pathogen enzymes were subjected to LC-MS, and the relative abundance of metabolites before and after treatment were comparatively analysed. Using two enzymes from different pathogens the in planta targets could be found by combining relatively simple enzymology with the power of untargeted metabolomics. Key to the method is dataset simplification based on natural isotope occurrence and statistical filtering, which can be scripted. The method presented here will aid in our understanding of plant-pathogen interactions and may lead to the development of new plant protection strategies.

Metabolomics of Solanum lycopersicum Infected with Phytophthora infestans Leads to Early Detection of Late Blight in Asymptomatic Plants

“…Using the MS and MS/MS spectra obtained from the LC-MS analysis, the following compounds were successfully annotated: steroidal glycoalkaloids α-tomatine (M1079T12; m / z 1078.5436), dehydrotomatine (M1077T12; m / z 1076.527), hydroxytomatine isomer I (M1095T10; m / z 1094.5382), the unknown glycoalkaloids UGA 11 (M1109T12; m / z 1108.5541) and UGA 28 (M1121T12; m / z 1120.5120) and the aglycon tomatidine (M414T20; m / z 414.3385) (Table 1), which occur naturally in tomatoes [49,50,51]. However, some studies of glycoalkaloids have shown that these molecules have antibiotic properties against a variety of fungi [52,53], suggesting that tomatine (α-tomatine and dehydrotomatine) may play a major role in disease resistance in the tomato plants [49,51,54]. Tomatidine is an important biomarker of infection, because bacterial and fungal pathogens secrete various types of tomatinase enzymes that can detoxify α-tomatine by removing one or more sugar residue [55,56].…”

Root infection by the nematode Meloidogyne incognita modulates leaf antiherbivore defenses and plant resistance to Spodoptera exigua

“…Steroidal glycoalkaloids in Solanum species function as first-line defense metabolites against pathogens and herbivores ( Güntner et al , 1997 ; Friedman, 2002 ; Ökmen et al , 2013 ; Chowański et al , 2016 ; Carere et al , 2016 ; Dahlin et al , 2017 ; Garcia et al , 2018 ). Despite the observed increase in steroidal glycoalkaloid concentration in the co-infected plants, we did not detect negative effects on the performance of S. exigua .…”

Applications of Biotechnology for Characterization of Plants and Pests as the Key Components of Plant Protection and Production Strategies: A Review

“…Evolution of modern insects (Yila et al, 2018), resistant to insecticides (Zhou et al, 2018), mechanism of cotton resistance to white fly Genes in Parasitic plants (Ichihashi et al, 2015), Ranjan et al, 2014;Yang et al, 2014); genes involved in the herbicide resistance (Zhou et al, 2017) Proteomics Characterize stress response (Komatsu et al, 2013;Aslam et al, 2017;Mosa et al, 2017) Plant-pathogen interactions (Kav et al, 2007;Mehta et al, 2008) insect pest defense mechanism (Kumar et al, 2016b), Aphids effectors sets (Thorpe et al, 2016) Partheniumhysterophorus (Pablos et al, 2017); Herbicide resistance (Tetard-Jone et al, 2018 Metabolomics Characterize massive metabolites responsible for various traits (Balmer et al, 2013;Tian et al, 2016a;Hong et al, 2016;Kumar et al, 2017b;Mosa et al, 2017;Tugizimana et al, 2018) plant defence compounds targeted by pathogens (Carere et al, 2016) resistant markers against Aphids (Undas et al, 2018) Allelochemicals (Beck et al, 2014;Scognamiglio et al, 2015) Metagenomics Interactions of plants and multiple microbes (Lara-Victoriano et al, 2011;Bashir et al, 2014;Melcher et al, 2014, Nazir 2016; functions of Soil rhizosphere (Ofalm et al, 2017;Soni et al, 2017;Jansson and Hofmockel, 2018) Aphids endosymbionts (De Clerck et al, 2015) Bioherbcides for weed management…”