The genetic landscape of Ceratocystis albifundus populations in South Africa reveals a recent fungal introduction event.
Geographical range expansion or host shifts is amongst the various evolutionary forces that underlie numerous emerging diseases caused by fungal pathogens. In this regard, Ceratocystis albifundus, the causal agent of a serious wilt disease of Acacia mearnsii trees in Africa, was recently identified killing cultivated Protea cynaroides in the Western Cape (WC) Province of South Africa. Protea cynaroides is an important native plant in the area and a key component of the Cape Floristic Region. The appearance of this new disease outbreak, together with isolates of C. albifundus from natural ecosystems as well as plantations of nonnative trees, provided an opportunity to consider questions relating to the possible origin and movement of the pathogen in South Africa. Ten microsatellite markers were used to determine the genetic diversity, population structure, and possible gene flow in a collection of 193 C. albifundus isolates. All populations, other than those from the WC, showed high levels of genetic diversity. An intermediate level of gene flow was found amongst populations of the pathogen. The results suggest that a limited number of individuals have recently been introduced into the WC, resulting in a novel disease problem in the area.
Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa.
Dong-Hyeon
DH
Lee
Department of Plant Science, FABI, University of Pretoria, Pretoria, South Africa.
Jolanda
J
Roux
Department of Genetics, FABI, University of Pretoria, Pretoria, South Africa.
Brenda D
BD
Wingfield
Department of Genetics, FABI, University of Pretoria, Pretoria, South Africa.
Irene
I
Barnes
Department of Plant Pathology, Stellenbosch University, South Africa.
Lizel
L
Mostert
Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa. Electronic address: Mike.wingfield@fabi.up.ac.za.
Michael J
MJ
Wingfield
D001203:Ascomycota / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D004271:DNA, Fungal / Q000235:genetics; D051456:Gene Flow; D014644:Genetic Variation; D005828:Genetics, Population; D018895:Microsatellite Repeats; D010935:Plant Diseases / Q000382:microbiology*; D013019:South Africa
D004271:DNA, Fungal
Canker; Emerging disease; Geographical range expansion; Host range expansion; Microascales; Microsatellite analysis