Genetic Bottlenecks for Two Populations of Ceratocystis fimbriata on Sweet Potato and Pomegranate in China

Abstract

Chinese isolates of Ceratocystis fimbriata from sweet potato (Ipomoea batatas) and pomegranate (Punica granatum) were genetically compared with a worldwide collection of isolates from a variety of hosts. Isolates from black-rotted storage roots of sweet potato in China, Japan, Australasia, and the United States had identical internal transcribed spacer (ITS) ribosomal DNA (rDNA) sequences and only minor variation in microsatellite alleles. Sequences of their mating type genes were most similar to those of isolates from various hosts in Ecuador, a center of diversity for sweet potato. Isolates from Colocasia esculenta (taro) and pomegranate from Yunnan and Sichuan had only one ITS rDNA sequence (haplotype ITS5). This haplotype, sequences of mating type genes, and microsatellite alleles linked these isolates to isolates from Eucalyptus stumps in South China and diseased Eucalyptus trees in Brazil, supporting the hypothesis that the pomegranate population originated from Brazil via cuttings of Eucalyptus. Isolates from sweet potato and pomegranate in China were interfertile with tester strains of C. fimbriata, confirming that the causes of the two epidemics in China belong to a single biological species. However, other isolates from Eucalyptus stumps were intersterile with the tester strains and had ITS rDNA sequences typical of the Asian species, C. cercfabiensis.

A host specialized form of Ceratocystis fimbriata causes seed and seedling blight on native Carapa guianensis (andiroba) in Amazonian rainforests

“…Fourteen microsatellite loci developed by Steimel et al (2004) and later mapped onto the C. fimbriata genome (Simpson et al, 2013) were analyzed. These microsatellite markers have been widely used in studies of population structure involving species within the LAC, especially in other Brazilian populations (Engelbrecht et al, , 2007aFerreira et al, 2010Ferreira et al, , 2011Harrington et al, 2015;Li et al, 2016;Ocasio-Morales et al, 2007;Oliveira et al, 2015a;Valdetaro et al, 2015). Each primer pair was specific to the flanking region of a simple sequence repeat, and one of the primers was fluorescently labeled.…”

Populations of Ceratocystis fimbriata on Colocasia esculenta and other hosts in the Mata Atlântica region in Brazil

“…(). These microsatellite markers were mapped onto the C. fimbriata genome (Simpson et al ., ) and used in previous population studies on C. cacaofunesta (Engelbrecht et al ., ), C. platani (Engelbrecht et al ., ; Ocasio‐Morales et al ., ), C. pirilliforms (Nkuekam et al ., ), and C. fimbriata (van Wyk et al ., ; Ferreira et al ., , , ; Harrington et al ., ; Oliveira et al ., ; Li et al ., ). Of the 16 loci used in some of the earlier studies, two (CfCAT3K and CfCAT9X) were not used because their alleles could not be consistently resolved with some isolates.…”

IMA Genome-F 11

“…It shows strong host specificity and does not infect tree hosts, in contrast to many other species in this genus (Baker et al 2003;Fourie et al 2018). The pathogen is known in various parts of the USA as well as in Asian countries including Papua New Guinea, China, Japan, Hawaii and New Zealand (Halsted and Fairchild 1891;Lewthwaite et al 2011;Li et al 2016). Population genetic analyses of isolates collected in these countries have revealed a very low genetic diversity in all the populations and C. fimbriata thus appears to be a near clonal species (Li et al 2016;Scruggs et al 2017).…”