The host range of Albugo candida extends from Brassicaceae through Cleomaceae to Capparaceae

Abstract

Capers (Capparis spinosa) are affected by white blister rust attributed to Albugo capparidis or, applying a broad species concept, to Albugo candida. Within the past 3 years, a great diversity within Albugo parasitic to the Brassicaceae has been observed. This has led to the description of two new specialized species within the parasites to Brassicaceae and the confirmation that Albugo lepidii is distinct from Albugo candida. In addition, it has been realized that Albugo candida has a broad host spectrum within the Brassicaceae, extending to the closely related Cleomaceae. Through molecular phylogenetic analysis of cox2 sequences and morphological comparison, it is demonstrated that the host range of A. candida extends to the Capparaceae. These findings are both relevant for practical plant pathology and raise questions regarding the mechanisms involved in the exceptional broad host range of Albugo candida, compared to other Albugo species.