Background
The usage of chemical fertilizers in modern agriculture has resulted in increasing of food production and supported a population of 7.7 billion people worldwide. On the other hand, the usage of chemical fertilizers causes environmental problems such as soil and river pollution. In addition, since fossil resources are used as raw materials, a new sustainable agricultural system with less environmental impact is demanded.
In recent years, utilization of useful soil microorganisms has been activated in response to this problem, and arbuscular mycorrhizal fungi are expected to be used as microbial fertilizers.
Arbuscular mycorrhizal fungi are classified in the order of the zygomycota glomus, and are fungi that lives symbiotically on the roots of plants. Furthermore, about 80% of terrestrial plants can form mycorrhiza, and mycorrhiza can pass phosphorus and water to the host plant beyond the root zone. This symbiotic relationship not only promotes growth, but also increases resistance of plants against drought and diseases.
However, since Arbuscular mycorrhizal fungi depends on the carbon source supplied from the host plants, pure culture could not be performed.
But recent research has revealed that palmitoleic acid, an unsaturated fatty acid, promotes the growth of Arbuscular mycorrhizal fungi and also induces its sporulation.
cf. アーバスキュラー菌根菌の純粋培養に世界で初めて成功 (Advancing pure culture of arbuscular mycorrhizal fungi)