Abstract:
The global spread of Eucalyptus pathogens is thought to be facilitated by the trade in seed for
the establishment of new plantations and breeding programmes. In this study we used highthroughput
amplicon sequencing to elucidate whether this might be true for the Eucalyptus
stem pathogen Teratosphaeria zuluensis in South Africa. DNA libraries were obtained for
seed-capsules, clean seed, one-month-old seedlings grown in a phytotron, plants grown in
vitro in a tissue culture facility as well as leaves and stems of three-month-old seedlings
exposed to a Eucalyptus plantation environment. The DNA libraries were sequenced using
high-throughput Illumina MiSeq and 454 technologies. Sequencing revealed the presence of several OTUs in the Botryosphaeriaceae, Mycosphaerellaceae and Teratosphaeriaceae in seed
and seed-capsules and amongst these, OTUs that cluster close to T. zuluensis. OTUs from the
Mycosphaerellaceae were also recovered from seedlings grown in a phytotron, in vitro
propagated seedlings and those exposed to the plantation environment. The results support
the view that important Eucalyptus pathogens, including T. zuluensis, can be spread via the
trade in seed.
