A new Rhizopogon species associated with Pinus amamiana in Japan

Abstract Pinus amamiana is an endangered Pinus species found only on Yakushima Island and Tanegashima Island, Japan. We surveyed remaining P. amamiana forests and found some sporocarps of Rhizopogon (Boletales), many species of which exhibit strict host specificity to a narrow range of Pinaceae trees and play critical roles in host establishment. Based on morphological characteristics and molecular phylogeny, here we describe Rhizopogon yakushimensis sp. nov. This new species belongs to a new clade, phylogenetically related to the subgenera Versicolores and Rhizopogon . We also confirmed its ectomycorrhizal association with P . amamiana by comparing rDNA ITS sequences between the sporocarps and ectomycorrhizal root tips.