Cassorrhizal Colonization: A Hostless Framework for Mycorrhizal Symbiotic Induction

This preprint documents an original experimental framework for inducing mycorrhizal symbiotic behavior in ectomycorrhizal fungi under entirely hostless laboratory conditions. The work introduces the novel term Cassorrhizal — defined as a state of false colonization where fungal mycelium is chemically or physically lured into a symbiotic response by a non-living, deceptive, or non-existent root structure — and describes the J160 media series developed to replicate the chemical, mechanical, and osmotic environment of a living root without one being present.

The framework covers the multi-role chemistry of a purpose-formulated low acyl gellan gum matrix as a root tissue analog, a pH-buffered TCA cycle entry point carbon system, hemicellulose signaling compounds, osmotic turgor management, and flavonoid-mediated pre-symbiotic effector induction via rutin hydrothermal conversion. The experimental isolate is a suspected Lactarius rubidus, though the framework is designed to apply broadly to ectomycorrhizal species. The target phenotype is Hartig net formation or attempted formation in the absence of a living host.