FABI Articles : Antifungal actinomycetes associated with the pine bark beetle, Orthotomicus erosus, in South Africa
previous pageAntifungal actinomycetes associated with the pine bark beetle, Orthotomicus erosus, in South Africa
Authors: Zander R. Human (contact author) Bernard SlippersZ. Wilhelm de Beer MichaelJ. Wingfield Stephanus N. VenterAbstract:
Actinomycete bacteria are often associated with insects that have a
mutualistic association with fungi. These bacteria are believed to be
important to this insect-fungus association as they produce antibiotics
that exclude other saprophytic fungi from the immediate environment. The
aim of this study was to investigate the presence of potentially
protective actinomycetes associated with Orthotomicus erosus, an alien invasive pine bark beetle, in South Africa. This
bark beetle and its relatives have an association with Ophiostomatales
species which are often the only fungi found in the bark beetle
galleries. We hypothesised that antibiotic-producing actinomycetes could
be responsible for the paucity of other fungi in the galleries by
producing compounds to which the Ophiostoma spp. are tolerant. Several actinomycetes in the genus Streptomyces and one Gordonia sp.
were isolated from the beetle. Interestingly, most isolates were from
the same species as actinomycetes associated with other pine-infesting
insects from other parts of the world, including bark beetles and the
woodwasp Sirex noctilio. Most actinomycetes isolated had strong antifungal properties against the selected test fungi, including Ophiostoma ips, which is the most common fungal symbiont of Orthotomicus erosus. Although the actinomycetes did not benefit Ophiostoma ips and the hypothesis was not supported, their sporadic association with Orthotomicus erosus suggests
that they could have some impact on the composition of the fungal
communities present in the bark beetle galleries, which is at present
poorly understood.
Read full paper HERE
Source: FABI