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 is 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 regards to Piedmont district (Northern Italy), Camellia japonica L. stimulates a remarkable interest in floriculture, being it one of the showpieces of the Lake Maggiore production. On this basis we saw fit a first experimentation, concerning the application of an inoculum constituted by a specific isolate and an inoculum composed by a consortium of different fungi and bacteria as alternative 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 evaluated too. Preliminary results on plants growth rate showed little response to mycorrhization, which was low. On the basis of these results, in order to select more camellia-specific AM fungi we considered five areas (public, private and abandoned gardens), hosting 19th century camellia specimens, for an AMF community composition analysis. This ongoing study could lead to the uncovering of specific AMF isolates, useful for the formulation of natural inocula capable of acting as biofertilizers, protecting and stimulating the growth of camellias, with a view to environmentally friendly and sustainable floriculture.