A Non-Destructive Method for Detecting Magnaporthe grisea Infection in Rice Plants at an Early Presymptomatic Stage...

Area of Science:

• Plant pathology
• Biochemistry
• Analytical chemistry

Background:

• Rice blast disease, caused by Magnaporthe grisea (MGR), significantly reduces crop yields.
• Plant-pathogen interactions involve phytohormone signaling and altered volatile organic compound (VOC) production.
• VOCs can serve as unique biomarkers for specific plant diseases.

Purpose of the Study:

• To develop a non-invasive method for early detection of MGR infection in rice using signature volatile organic compounds (S-VOCs).
• To identify specific S-VOCs associated with the presymptomatic stage of MGR infection in rice.

Main Methods:

• Artificial inoculation of rice leaves with MGR.
• Monitoring volatile profiles using headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS).
• Analysis of VOCs at healthy, asymptomatic MGR-challenged, and symptomatic MGR-challenged stages.

Main Results:

• Two compounds, octadecanal and 1-nonanol, were exclusively detected in asymptomatic MGR-infected rice leaves.
• MGR-infected plants showed increased production of methyl-salicylate (MeSA) and reactive oxygen species (ROS).
• Octadecanal and 1-nonanol effectively differentiated between healthy and MGR-infected plant headspaces at early infection stages.

Conclusions:

• Octadecanal and 1-nonanol are potential S-VOCs for the early, non-invasive detection of rice blast disease.
• MeSA and ROS play roles in plant signaling during MGR infection.
• VOC analysis offers a promising approach for high-throughput, early-stage plant disease diagnostics.