Transcriptomic profiling of wheat (Triticum Aestivum L.) response to infection by the wheat blast fungus Magnaporthe Oryzae Triticum

TL;DR

This study uses transcriptomic analysis to understand how wheat responds to infection by the wheat blast fungus at different stages.

Contribution

The study provides a detailed temporal framework of wheat's transcriptional responses and pathogen effector expression during wheat blast infection.

Findings

Wheat shows stage-specific transcriptional changes, with immune and detoxification pathways activated early in infection.

At 48 hours post-infection, wheat exhibits suppressed photosynthesis and chloroplast functions, linked to metabolic strain and necrosis.

Pathogen effector candidates are temporally induced, aligning with host immune responses and infection progression.

Abstract

The wheat blast fungus Magnaporthe oryzae pathotype Triticum (MoT) poses a severe threat to global wheat (Triticum aestivum L.) production, yet the molecular mechanisms underlying tissue invasion remain poorly understood.

We performed dual RNA-seq analysis of MoT-inoculated wheat leaves at 0, 24, 36, and 48 hpi, mapping reads separately to the wheat and M. oryzae genomes to capture stage-specific host responses and pathogen gene expression across progressive infection stages.

Wheat exhibited pronounced stage-specific transcriptional reprogramming, with peak differential gene expression at 36 hpi and visible symptoms at 48 hpi. The 24 hpi stage was characterized by rapid induction of immune- and defense-related pathways, including innate immunity and detoxification processes, along with downregulation of cell wall and membrane biosynthesis. By 36 hpi, wheat maintained sustained activation of immune and detoxification pathways, while chloroplast- and photosynthesis-associated genes were broadly repressed, consistent with transcriptional features of metabolic constraint. At 48 hpi, coinciding with lesion initiation, transcriptomes showed persistent, metabolically costly immune and defense responses together with extensive suppression of photosynthesis- and chloroplast-associated functions, which were associated with metabolic strain and a transition toward necrosis. Analysis of pathogen-derived reads revealed temporal induction of multiple effector candidates, including known M. oryzae orthologs and additional effector-like proteins, highlighting coordinated temporal patterns between host immune and metabolic response as well as stage-specific pathogen effector expression.

Together, these findings provide a temporal framework for wheat blast susceptibility and highlight key host pathways and effector candidates that define critical windows for functional dissection of MoT virulence and wheat susceptibility.

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