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Published on: March 10, 2020
Root exudate of pmi tomato mutant M161 reduces AM fungal proliferation in vitro
Vijay Gadkar1, Rakefet David-Schwartz, Gerald Nagahashi
1Department of Agronomy and Natural Resources, ARO, the Volcani Center, PO Box 6, Bet Dagan 50 250, Israel.
Abstract:
Soluble factors released from roots of the pre-mycorrhizal infection (pmi) myc(-) tomato mutant M161 were analyzed and compared with normal wild-type released factors. Aseptic whole exudates from the M161 mutant retarded the proliferation of Glomus intraradices in vitro. When the whole exudate was further fractionated on a C18 SEPAK cartridge, the 50/70% methanol fraction showed an activity against hyphal tip growth of Gigaspora gigantea and Gl. intraradices. Preliminary characterization of the exudate suggests that the inhibitory moieties are heat labile, bind to PVPP (polyvinyl polypyrrolidone), and are not volatile. This is the first reported instance of the inhibition by a myc(-) plant being ascribed to inhibitory component(s) released in root exudate.
Insights
Root exudates from a mutant tomato (myc(-)) inhibit beneficial mycorrhizal fungi. This study identifies specific inhibitory compounds in the root exudate, offering insights into plant-fungal interactions.
Area of Science:
- Plant-microbe interactions
- Mycology
- Plant physiology
Background:
- Mycorrhizal fungi are crucial for plant nutrient uptake.
- The tomato mutant M161 (myc(-)) affects pre-mycorrhizal infection (pmi) stages.
- Root exudates play a role in mediating plant-microbe communication.
Purpose of the Study:
- To analyze and compare soluble factors from myc(-) tomato mutant M161 root exudates with wild-type.
- To identify components in root exudates that inhibit mycorrhizal fungi.
- To investigate the characteristics of these inhibitory factors.
Main Methods:
- Aseptic culture of tomato mutant M161 and wild-type.
- Collection and fractionation of root exudates using C18 SEPAK cartridge.
- In vitro assays to assess inhibition of Glomus intraradices and Gigaspora gigantea hyphal growth.
- Preliminary characterization of inhibitory moieties (heat lability, PVPP binding, volatility).
Main Results:
- Whole root exudates from M161 mutant significantly retarded Glomus intraradices proliferation in vitro.
- A specific fraction (50/70% methanol) of the M161 exudate demonstrated inhibitory activity against hyphal tip growth of both Gigaspora gigantea and Gl. intraradices.
- The inhibitory compounds are heat labile, bind to polyvinyl polypyrrolidone (PVPP), and are not volatile.
Conclusions:
- This is the first report of inhibitory components in root exudates from a myc(-) plant.
- The identified soluble factors from the M161 mutant actively inhibit the growth of key arbuscular mycorrhizal fungi.
- These findings provide novel insights into the molecular mechanisms underlying plant-mycorrhizal interactions and potential strategies for modulating them.
