Abstract:
The fungal pathogen, Ceratocystis manginecans, has caused serious canker and wilt
disease on Mangifera indica (mango), on legume tree species in Oman and Pakistan and on
Acacia spp. in Indonesia. A Ceratocystis species, with similar morphology to C.
manginecans, has recently been reported in Vietnam, causing severe disease of Acacia
trees. Previous population genetic studies on isolates from M. indica in Oman and Pakistan
have shown that the pathogen represents a single clonal haplotype, indicative of an
introduced pathogen. The aim of this study was to investigate the genetic diversity and population structure of 160 C. manginecans isolates, from four host-associated populations
from Oman, Pakistan, Indonesia and Vietnam. This was done by applying a combination of
14 previously developed microsatellite markers and a new set, designed in this study from
two different C. manginecans genomes. Sequence data confirmed that the isolates in
Vietnam are the same species as those in Indonesia and were thus identified as C.
manginecans. Unlike the populations in Oman and Pakistan, relatively high levels of genetic
variation were found for the isolates from Indonesia and Vietnam. The Vietnam population
was significantly differentiated from the other populations and isolates from this area had the
highest level of genetic diversity thus far encountered for the pathogen.
