Two novel Phytophthora species from the southern tip of Africa

Abstract

The microbial diversity associated with natural vegetation in the Greater Cape Floristic Region of South Africa is largely unexplored. As part of the Cape Citizen Science programme and independent research, surveys were conducted between 2015 and 2019 to catalogue the diversity of Phytophthora species associated with many plant species endemic to this region. Using soil and water baiting techniques, six isolates of the provisionally described Phytophthora taxon emzansi were recovered, together with three isolates of an undescribed Phytophthora species. In this study, we used both molecular and morphological data to describe these Phytophthora species. Isolates of P. emzansi sp. nov. and P. afrocarpa sp. nov. formed monophyletic lineages within Phytophthora Clades 2 and 10, respectively. Phytophthora emzansi sp. nov. and P. capensis are sister species residing in the P. citricola species complex, and both are homothallic. Phytophthora afrocarpa sp. nov. is a sister species to P. gallica, and both these taxa are sexually sterile. The present study augments our knowledge of the unique Phytophthora species associated with the native vegetation of southern Africa.