Magnaporthe oryzae Systemic Defense Trigger 1 (MoSDT1)-Mediated Metabolites Regulate Defense Response in Rice

Abstract

Background: Some of the pathogenic effector proteins play an active role in stimulating the plant defense system to strengthen plant resistance. Results: In this study, ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC/Q-TOF-MS) was implemented to identify altered metabolites in transgenic rice containing over-expressed M. oryzae Systemic Defense Trigger 1 (MoSDT1) that was infected at three-time points. The characterized dominating metabolites were organic acids and their derivatives, organic oxygen compounds, lipids, and lipid-like molecules. Among the identified metabolites, shikimate, galactinol, trehalose, D-mannose, linolenic acid, dopamine, tyramine, and L-glutamine are precursors for the synthesis of many secondary defense metabolites Carbohydrate, as well as amino acid metabolic, pathways were revealed to be involved in plant defense responses and resistance strengthening. Conclusion: The increasing salicylic acid (SA) and jasmonic acid (JA) content enhanced interactions between JA synthesis/signaling gene, SA synthesis/receptor gene, raffinose/fructose/sucrose synthase gene, and cell wall-related genes all contribute to defense response in rice. The symptoms of rice after M. oryzae infection were significantly alleviated when treated with six identified metabolites, i.e., galactol, tyramine, L-glutamine, L-tryptophan, α-terpinene, and dopamine for 72 h exogenously. Therefore, these metabolites could be utilized as an optimal metabolic marker for M. oryzae defense.

How do plants defend themselves against pathogens-Biochemical mechanisms and genetic interventions

“…In plants, single metabolic markers have been suggested to assess the stress intensity, e.g., proline, which accumulates drought stress-prone plant species (Hayat et al 2012). Later, metabolic variables were found to be useful markers to detect stress damage or resistance and hence the diagnostic markers have been developed in the form of enzymes (Gibon et al 2004), metabolites (Korn et al 2010;Duan et al 2021), transcripts (Tamaoki et al 2013) and amino acids (Zhao et al 2021).…”

“…Lately, Zhao et al (2021) identified proline and alanine as important metabolic markers for head blight resistance in wheat. In a recent study by Duan et al (2021), metabolites namely shikimate, galactinol, trehalose, D-mannose, linolenic acid, dopamine, tyramine, and L-glutamine were identified as metabolic markers imparting plant defense response against rice blast. The list of different plant metabolic markers identified to provide resistance against the diseases has been given in Table 4.…”

The chromosome‐level genome of a free‐floating aquatic weed Pistia stratiotes provides insights into its rapid invasion

“…Our result showed that the terms “Sphingolipid metabolism”, “Plant‐pathogen interaction” and “Biotin metabolism” were found to be enriched (Figure S6). Both sphingolipids and biotin played a predominant role in plant defence, especially in disease resistance (Duan et al, 2021; Yanagawa et al, 2017).…”