(This is a summry. The full text including references is available on request.)
There are various studies on the influence of chitosan on mycorrhiza. Generally positive effects on the growth of mycorrhizal fungi and roots of the associated plants could be observed, followed by better plant development and harvest. The enzymes (chitinase and chitasanase) produced by plants to resist infections are specifically effective against the cell walls of phytopathogenic fungi but are inoperative against the cell walls of mycorrhiza. No harmful increase, for mycorrhiza, in chitinases and chitosanases production by soil inhabiting bacteria after treatment with chitosan was observed. The increased lignification of plant cell walls after treatment with chitosan is also not a problem for mycorrhiza fungi of arbuscular or ectotrophic because both engage the roots of plants near the root cap where the rhizodermis is still intact and forms root hairs. At this part of the root the exodermis is yet not lignified so the mycorrhiza can engage their linkage with the plants root cortex unobstructed. This is not altered due to treatment with ChitoPlant.
“[...] this biopolymer (chitosan) is composed of polysaccharides that stimulate the activity of beneficial microorganisms in the soil such as [...], mycorrhiza and rhizobacteria. This alters the microbial equilibrium in the rhizosphere disadvantaging plant pathogens.”
“While infection of the root pathogen [...] was inhibited, formation of arbuscular mycorrhiza [...] was not affected at all [...]. This indicates that the structure of the cell wall of mycorrhizal fungi is resistant to the attack of defense-related chitinases.”
“The distinction between chitinases and chitosanases is that chitinase specifically cleaves the N-acetyl-D-glucosaminidic bonds while chitosanase cleaves the β-D-glucosaminidic bonds. Chitosanases are able to hydrolyze all kinds of linkages in chitosan except the GlcNAc-GlcNAc bond.”
“At harvest, yields for the [conventional fungicide]-NOCC, NOCC and AMF-NOCC treatments were significantly higher than the un-sprayed, non-mycorrhizal control and were not significantly different to the [conventional fungicide]-sprayed control. The results are discussed in relation to the production of seed potatoes for organic (ecological) growers.”