Department of Applied Biology, University of Perugia, Borgo XX Giugno 74, Perugia, 06121, Italy.
Mycorrhiza. 2012 Jul;22(5):383-92. doi: 10.1007/s00572-011-0413-z. Epub 2011 Oct 11.
Pecan (Carya illinoinensis) is an economically important nut tree native to the Mississippi basin and cultivated worldwide. In North America, species of truffles are regularly found fruiting in productive pecan orchards and the truffle genus Tuber appears to be abundant in pecan ectomycorrhizal (EM) communities. As an initial step to determine the feasibility of co-cropping European truffle species with pecan, we evaluated whether mycorrhizae of highly esteemed European truffle species (Tuber aestivum Vittad. T. borchii and T. macrosporum) could be formed on pecan seedlings. Seedlings were inoculated with truffle spores and were grown in a greenhouse for 10 months. Levels of EM colonization were estimated visually and quantified by counting EM tips. Ectomycorrhizae were identified both morphologically and molecularly with species-specific amplification and by sequencing of the ITS region of the nuclear ribosomal DNA (nrDNA). Both T. borchii and T. aestivum spores produced well-formed ectomycorrhizae on pecan seedlings with average root colonization levels of about 62% and 42%, respectively, whereas no ectomycorrhizae of T. macrosporum were formed. The anatomy and morphology of these truffle ectomycorrhizae on pecan was characterized. The co-cropping of T. aestivum and T. borchii may hold promise as an additional stream of revenue to pecan growers, although, further studies are needed to assess whether this symbiosis is maintained after planting in the field and whether truffle production can be supported by this host species.
美洲山核桃（Carya illinoinensis）是原产于密西西比河流域的一种经济价值很高的坚果树，现已在世界各地广泛种植。在北美洲，经常可以在生产力高的美洲山核桃果园中发现块菌属（Tuber）的真菌果实，而栓菌属（Tuber）似乎在美洲山核桃外生菌根（EM）群落中很丰富。作为确定欧洲块菌物种与美洲山核桃共生的可行性的初步步骤，我们评估了高度受推崇的欧洲块菌物种（Tuber aestivum Vittad.、T. borchii 和 T. macrosporum）的菌根是否可以在美洲山核桃幼苗上形成。幼苗用块菌孢子接种，并在温室中生长了 10 个月。通过目测和计数 EM 尖端来估计 EM 定植水平。通过物种特异性扩增和核核糖体 DNA（nrDNA）ITS 区的测序，对形态学和分子学上的外生菌根进行了鉴定。T. borchii 和 T. aestivum 孢子都在美洲山核桃幼苗上形成了形态良好的外生菌根，平均根定植水平分别约为 62%和 42%，而 T. macrosporum 则没有形成外生菌根。对这些在美洲山核桃上的块菌外生菌根的解剖结构和形态进行了描述。T. aestivum 和 T. borchii 的共生种植可能为美洲山核桃种植者带来额外的收入来源，尽管还需要进一步研究来评估这种共生关系在田间种植后是否得到维持，以及这种宿主物种是否能够支持块菌的生产。
