Selection of Arbuscular Mycorrhizal Fungal Isolates for Sustainable Floriculture

Symbiotic associations between arbuscular mycorrhizal fungi (AMF) and plant roots are widespread in natural environments and provide a range of benefits to the host plant, above all improving nutrition. The aim of our study was to verify if, in controlled environments such as greenhouses, the use of inocula based on these beneficial soil fungi could improve the growth of economically important plants. With particular regard to the Piedmont district (Northern Italy), Camellia japonica L. stimulates a remarkable interest in floriculture, it being one of the showpieces of the Lake Maggiore production. On this basis we decided to experiment with the application of an inoculum consisting of a specific isolate and an inoculum composed of a consortium of different fungi and bacteria as alternatives to fertilization in pot cultivated C. japonica. We undertook, in parallel, a molecular characterization of the applied AMF consortium inoculum by means of PCR-RFLP and sequencing of a region of the 18S rDNA. Mycorrhization levels in roots were also evaluated. Preliminary results on plant growth rates showed little response to mycorrhization, which was low. On the basis of these results, in order to select more camellia-specific AMF, we considered five areas in public, private, and abandoned gardens hosting 19th century camellia specimens, for an AMF community composition analysis. This ongoing study may lead to the discovery of specific AMF isolates, useful for the formulation of natural inocula capable of acting as biofertilizers that protect and stimulate the growth of camellias, with a view to environmentally friendly and sustainable floriculture.