A sheathing mycorrhiza between the tropical bolete Phlebopus spongiosus and Citrus maxima

作者：Nguyen Duc Hoang Pham^*; Yamada Akiyoshi; Shimizu Kiminori; Noda Katsuji; Le Anh Tuan Dang; Suzuki Akira

来源：Mycoscience, 2012, 53(5): 347-353.

DOI：10.1007/s10267-011-0177-5

• Black bolete
• Ectomycorrhiza
• Pomelo
• Thick mantle

Phlebopus (Ph.) spongiosus was recently described from several pomelo orchards (Citrus maxima) in southern Vietnam. This fungus was suspected to associate with pomelo plants as an ectomycorrhiza, although members of the genus Phlebopus have previously been presumed saprotrophic. To clarify this association, pomelo roots collected from the orchard (in situ roots), and those cultured with Ph. spongiosus (in vitro roots) in test tubes for 12 wk, were examined for ectomycorrhizal colonization. Both in vitro and in situ roots were analyzed for colonization using fungal LSU nuclear ribosomal DNA sequencing. The in situ roots exhibited the anatomical features of ectomycorrhizae: a thick fungal mantle, Hartig net, and extramatrical hyphae. The Hartig net, however, was very rare and showed discontinuous development. The in vitro association between Ph. spongiosus and C. maxima showed ectomycorrhiza-like structures, i.e., mantles and rhizomorphs in the plant roots, but no Hartig net development in the roots. Continuous hyphal penetration was restricted to the exodermis in both in situ and in vitro roots. Although the association between Ph. spongiosus and C. maxima could be considered ectomycorrhizal, its anatomy matches the unique feature known as sheathing mycorrhiza.

• 出版日期2012-9