Dual and Single-species Nematode Infections Distinctly Modulate Defense Metabolism in Brassica nigra Roots

Area of Science:

• Plant pathology
• Plant metabolomics
• Nematode-plant interactions

Background:

• Plant roots interact with diverse soil organisms, including plant-parasitic nematodes (PPNs) like Meloidogyne spp. and Pratylenchus spp., which cause significant crop damage.
• Black mustard (Brassica nigra) can be simultaneously infected by Meloidogyne incognita and Pratylenchus penetrans, posing complex challenges to plant defense.

Purpose of the Study:

• To investigate how dual infections by M. incognita and P. penetrans affect the root metabolome of B. nigra.
• To correlate changes in root metabolome with the early infection success of each nematode species.

Main Methods:

• Utilized untargeted and targeted metabolomics to analyze root samples from single and dual nematode infections.
• Quantified early infection success by measuring nematode penetration at three days post-inoculation.

Main Results:

• Dual infections enhanced M. incognita penetration but did not affect P. penetrans success.
• Distinct metabolic changes were observed in dual infections, including reduced indole glucosinolates (GSL), lignans, and phenylpropanoids.
• Specific GSL classes were differentially affected: allyl GSL (sinigrin) increased with P. penetrans, while gluconasturtiin increased with M. incognita.

Conclusions:

• Dual nematode infections induce unique plant defense responses in B. nigra roots compared to single infections.
• These altered metabolic profiles have significant consequences for the early infection dynamics of co-infecting nematode species.