The Use of PTI-Marker Genes to Identify Novel Compounds that Establish Induced Resistance in Rice

Abstract

Compounds that establish induced resistance (IR) in plants are promising alternatives for the pesticides that are progressively being banned worldwide. Screening platforms to identify IR-establishing compounds have been developed, but none were specifically designed for monocot plants. Here, we propose the use of an RT-qPCR screening platform, based on conserved immunity marker genes of rice as proxy for IR induction. Central regulators of biotic stress responses of rice were identified with a weighted gene co-expression network analysis (WGCNA), using more than 350 microarray datasets of rice under various sorts of biotic stress. Candidate genes were narrowed down to six immunity marker genes, based on consistent association with pattern-triggered immunity (PTI), both in rice plants as in rice cell suspension cultures (RCSCs). By monitoring the expression of these genes in RCSCs upon treatment with candidate IR-inducing compounds, we showed that our marker genes can predict IR induction in rice. Diproline, a novel IR-establishing compound for monocots that was detected with these marker genes, was shown to induce rice resistance against root-knot nematodes, without fitness costs. Gene expression profiling of the here-described PTI-marker genes can be executed on fully-grown plants or in RCSCs, providing a novel and versatile tool to predict IR induction.

The phenylpropanoid pathway inhibitor piperonylic acid induces broad-spectrum pest and disease resistance in plants

“…For RT-qPCR, RNA was extracted from ±100 mg ground tissue (RNEasy Plant kit, Qiagen,), DNAse-treated (DNAse I, Thermo Fisher Scientific) and converted to cDNA (Tetro cDNA synthesis kit, Bioline). RT-qPCR conditions were as in De Kesel et al (2020). Primer sequences are listed in Supplementary Table S1 .…”

Cucurbitaceae COld Peeling Extracts (CCOPEs) Protect Plants From Root-Knot Nematode Infections Through Induced Resistance and Nematicidal Effects

“…Rice cell suspension cultures (RCSCs) were treated with candidate solutions to evaluate the induction of a validated pattern-triggered immunity (PTI)-marker gene set. This in vitro transcriptional stimulation has been shown to be a useful proxy to unveil an IR-inducing capacity of assayed products (De Kesel et al, 2020). Extracts derived from pumpkin (Cucurbita moschata cv.…”

“…cantalupensis; mCOPE) peelings were all found to be promising IR stimuli. Indeed, convening with the threshold set by De Kesel et al (2020), at least four of the six screening genes were significantly upregulated in the RCSCs upon treatment with the evaluated CCOPEs (Figure 1).…”

Altering the Sex Pheromone Cyclo(l-Pro-l-Pro) of the Diatom Seminavis robusta towards a Chemical Probe

“…The diketopiperazine was reported to be a constituent of pheromonal secretions in two other species, namely in the femoral gland of the Sceloporus virgatus lizard [ 28 ] and the mating plug of the Bombus terrestris bumblebee [ 29 ], and was also identified in the Aspergillus fumigatus fungus, the Lucilia sericata blowfly and the Antarctic Pseudoalteromonas haloplanktis bacterium [ 28 ]. Recently, 1 was also shown to be an effective induced resistance stimulus for rice plants [ 30 ], triggering a systemically enhanced defense against the root-knot nematode Meloidogyne graminicola .…”