Abstract:
Species in the Ceratocystis manginecans complex are important fungal pathogens of plantation
trees globally. The most important hosts include species of Eucalyptus, Acacia, Mangifera, and
Punica. Despite their relevance and widespread occurrence, little is known regarding their population
genetics and how this might relate to their host associations or geographic regions in which they occur.
A global collection of 491 isolates representing the C. manginecans complex, from four different plant
hosts and nine countries, were genotyped using microsatellite markers. Population genetic analyses
using numerous tools were conducted to interrogate how their genetic diversity and structure might
be affected by host or areas of occurrence. Results of genetic diversity studies showed that when
grouping isolates into populations based on their host associations, the population on Eucalyptus
was most diverse, and it also has a broad global distribution. When considering countries of origin
as a basis for defining populations, the gene and genotypic diversity were highest in populations
from China, Indonesia, and Brazil. In contrast, populations from Oman and Pakistan collected
from Mangifera had the lowest genetic diversity and were clonal. Molecular variance, population
differentiation, and network and structure analyses showed that the genetic structure of isolates in
the C. manginecans complex is influenced by both host association as well as geographical isolation.
Furthermore, the results reflected the movement of genotypes between plant hosts and geographic
regions that have implications regarding the broad global distribution of this pathogen.
Description:
SUPPLEMENTARY MATERIAL: Figure S1. Linkage disequilibriumtesting (IA, p-values > 0.01). Table S1. List of Ceratocystis isolates included in the microsatellite study and the alleles scored at each locus using GeneScanTM fragment analyses and the GeneMapperTM software. Table S2. List of Ceratocystis isolates included in the microsatellite study and the alleles scored at each locus based on results obtained by sequencing. Table S3. GenBank numbers of alleles sequenced in this study.