Two evolutionarily conserved fatty acid desaturases control the production of omega-3 fatty acids and bioactive jasmonates in Marchantia polymorpha

ABSTRACT: In the model bryophyte Marchantia polymorpha, omega-3 (n3) polyunsaturated fatty acids (n3-PUFAs) and long-chain n3-PUFAs (n3-LCPUFAs) serve as precursors for bioactive jasmonates. However, how omega-3 fatty acid desaturases (n3-FADs) contribute to the production of n3-PUFAs and jasmonates remain unexplored. Here, we study the n3-FAD-dependent jasmonate signaling in the liverwort M. polymorpha. We found that MpFAD3, localized to the endoplasmic reticulum, prefers omega-6 (n6) arachidonic acid (ARA, 20:4n6) as the substrate thus controlling the biosynthesis of n3-LCPUFA derived jasmonates. Conversely, MpFAD7, found in the chloroplast, takes hexadecadienoic acid (HDA, 16:2n6) and linoleic acid (LA, 18:2n6) as substrates more efficiently and regulates the production of n3-PUFA derived jasmonates. Certain promiscuity was observed for these enzymes as evidenced by increased n6-(LC)PUFA levels in the doble Mpfad3fad7 mutant compared to single mutant lines individually. Mpfad7 and Mpfad3fad7 plants were more resistant to Fusarium oxysporum infection compared to wildtype control, suggesting a prominent role for n3-PUFA derived jasmonates in regulating defenses against necrotrophic pathogens. Remarkably, despite the lack of jasmonate-dependent anti-herbivore defenses in Mpfad3fad7 plants, Spodoptera exigua caterpillars performed equally badly on this double mutant and on wildtype plants, which states the dietary importance of essential n3-(LC)PUFAs for the caterpillar. Our results suggest that two conserved but specialized n3-FADs control n3-(LC)PUFA and jasmonate biosynthesis in Marchantia, and that food quality, namely the type and ratio of n3-(LC)PUFAs, contributes to insect performance in addition to jasmonate-dependent plant defenses.

ORGANISM(S): Marchantia polymorpha

PROVIDER: GSE305196 | GEO | 2026/07/22

REPOSITORIES: GEO