Arambarria the pathogen involved in canker rot of Eucalyptus, native trees wood rots and grapevine diseases in the Southern Hemisphere

Arambarria (Hymenochaetales, Basidiomycota) is a monotypic genus recently described to accommodate specimens from the Patagonian forests of Argentina wrongly assigned in the past to Inocutis jamaicensis. On the basis of a wide sampling of strains and phylogenetic analysis inferred from combined sequences including the nuc rDNA ITS1‐5.8‐ITS2 region, 28S rDNA D1‐D2 domains and partial sequences of translation elongation factor 1‐a (tef1‐α), we demonstrate that this genus is associated with an important canker rot of eucalypt plantations in Uruguay, to wood rots of many native and exotic hosts, and to “hoja de malvón” and chlorotic leafroll of grapevines diseases in Central Chile, Central Argentina and Uruguay, formerly assigned to I. jamaicensis and/or Fomitiporella sp. The combined phylogenetic analysis showed the existence of three closely related clades that corresponded to (1) the Pampas of Uruguay and Argentina (“uruguay” clade), (2) the Monte, Chaco Serrano and Yungas forests of Argentina (“cognata” clade) and (3) the Patagonian Andes forests and Chilean Province (“destruens” clade). Lack of morphological differences between taxa from the three clades, their occurrence in both native and exotic hosts, previous results showing interfertility between isolates from Uruguay and Argentina, and the lack of full support in the concatenated ITS + 28S + tef1‐α analysis, prevents us to distinguish and describe three different taxa; the proper name of the taxon being Arambarria cognata comb. nov. A fourth, distinctly separated clade corresponded to South African strains isolated from vineyards representing an undescribed taxon associated with Esca grapevine disease in that country. Arambarria is shown to be unrelated to Inocutis, with which it was confused in the past and, so far, remains restricted to the Northern Hemisphere in America (Mexico, Jamaica and the USA).