Mycorrhizal synthesis of Tuber pseudohimalayense with seven broad-leaved trees and Pinus armandii

Truffle cultivation is successfully applied throughout the world for several truffles of European origin. However, just two Chinese black truffles (Tuber indicum and T. himalayense) have been cultivated with a favorable outcome so far. Tuber pseudohimalayense is a black truffle of significant economic relevance in China, but little is known about its mycorrhizal ecology and it is not cultivated in orchards yet. Here, we selected seven broad-leaved tree species (Quercus fabrei, Q. aliena, Castanea mollissima, Carya illinoinensis, Q. glauca, Castanopsis orthacantha, Betula costata), and one coniferous tree (Pinus armandii), and inoculated them with T. pseudohimalayense spore suspension using axenically germinated seedlings under greenhouse conditions. The obtained mycorrhizae, well-developed, were analyzed from the morpho-anatomical and molecular points of view, and their main characteristics described. Synthesized T. pseudohimalayense mycorrhizae showed similar characters on all tree species, with a typical interlocking pseudoparenchymatous mantle and Hartig net, swollen appearance, yellow-brownish color, and long hyaline emanating hyphae with right-angle ramifications. These features are similar to those reported for mycorrhizae formed by related black truffle species. The successful mycorrhizal synthesis of T. pseudohimalayense on multiple trees species indicates that it has potential for cultivation in China.