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The infection and diversity of Diplodia pinea in asymptomatic Pinus patula trees

Bihon, W., Slippers, B., Burgess, T.ORCID: 0000-0002-7962-219X, Wingfield, M.J. and Wingfield, B.D. (2009) The infection and diversity of Diplodia pinea in asymptomatic Pinus patula trees. In: 2009 APS Annual Meeting, 1 - 5 August, Portland, OR, USA.

Abstract

Diplodia pinea (= Sphaeropsis sapinea) is a common latent pathogen in Pine trees in many parts of the world, including South Africa. The aim of this study was to determine the distribution and frequency of endophytic D. pinea infections in Pinus patula trees, seedlings and seeds. The diversity of the endophytic isolates from trees was then determined using 13 microsatellite markers. Isolations of the fungus were successfully made from the main stem, branches and cones of asymptomatic P. patula trees. The genotypic diversity of these isolates was high, ranging between 43% to 68%. The haplotypes in each tree were not spatially grouped, but randomly distributed throughout the tree, indicating numerous individual infections over time. Seedlings grown in areas where mature pines were absent (either in nurseries or in the open field) contained low levels or no D. pinea infection, while those grown in close proximity to mature trees had a 40% incidence of infection. Furthermore, the fungus could only be isolated from 2–3% of surface disinfected seeds. These data indicate that seeds play a limited role in dissemination of D. pinea, although the large amount of seed moved internationally increases the changes of dispersal. The fungus infects plants repeatedly from a young age from inoculum produced on surrounding trees. Latent infections can then persist in the trees for long periods as local infections throughout the tree, even deep in heart of the main stem.

Item Type: Conference Item
Murdoch Affiliation: School of Biological Sciences and Biotechnology
Publisher: American Phytopathological Society
Conference Website: https://www.apsnet.org/meetings/annual/meetingarch...
URI: http://researchrepository.murdoch.edu.au/id/eprint/52944
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