The black truffle (Tuber melanosporum) is one of the agroforestry products with greatest potential in our country. Truffle cultivation is a relatively recent activity, thus it keeps a lot of unknows, mainly related to the factors that trigger the fruiting of the fungus. The influence of certain microorganisms on the formation of mycorrhizae of Tuber genus is demonstrated, but there is little published literature. We also think that they could have a key role in the fruiting of the fungus. The main objective that this research team aims to solve with this funding proposal, is to check which microbial groups or microbial species play an essential role in the formation of mycorrhizae and fruiting bodies of T. melanosporum. Therefore there will be taken, on the one hand, soil samples, rhizosphere and ectomycorrhizae both planting and nursery, and on the other hand, truffle samples at different maturity stages. On these samples, cultivable microbiota will be analyzed, and species appearing in a differential mode on mycorrhizae producing trees and fruiting bodies will be identified. The species of greatest interest will be properly genotyped and preserved. This will be complemented with the analysis of the total microbiota present in ectomycorrhizae and fruiting bodies of T. melanosporum using a metagenomic approach and a microbial ecology study. Thereby, there will be obtained information about uncultivable microorganisms present in the samples. It is expected to detect and characterize a microbial group with clear influence on vegetative growth and fruiting, which effect can be tested in later works by applying them in different combinations and concentrations in both, substrates nurseries and established plantations.
As a preliminary step of microbiological analysis of carpophores, standardizing maturity criteria will be tuned up. The ranges of maturity will be established with data obtained from a study of colorimetry of peridium and glebe, the concentration of melanin in the glebe, the percentage of asci with mature ascospores, the instrumental aromatic profile and organoleptic characterization from an expert tasting panel. Furthermore, this methodology will allow us to classify carpophores easily, and could be used in fresh truffle markets to assess the value of a more reliable and standardized manner.
The components of the research team belong to four research groups: Truffle culture from CITA (Agrifood Research and Tecnology Centre of Aragón), Foods of Plant Origin from the University of Zaragoza, Analysis and Assessment of Food Safety from the University of Zaragoza and Department of Environmental Biology from the University of Navarra. The proposal has the support of companies from devoted to mycorrhized seedling production, truffle producers and truffle growers associations.
Pedro Marco Montori, Sergi García Barreda (CITA); Ana Mª de Miguel (Univ. Navarra); Domingo Blanco Parmo, Pilar Conchello Moreno (Univ. Zaragoza)