Wednesday, 4 January 2012

Mutant killer fungus

Our latest review is of a study that reveals something close to science fiction in the interactions between a bark beetle, a fungus and the host plant.  It is a very good paper that presents a well executed study, that includes multiple methods to consider the question:
Do novel genotypes drive the success of an invasive bark beetle-fungus complex?  Implications for potential reinvasion.

Lu M, Wingfield MJ, Gillette N and Sun JH, Ecology. 2011 92(11):2013-9

Our Review: Parry H, Lonsdale M: 2011. 

This fascinating paper explores the emergence of a mutant, killer fungus as a result of an unholy alliance between the fungus, its beetle vector, and its host plant. It is important for invasion ecologists because it emphasises the role of novel genotypes in invasion success and it does so in the context of a three-way interspecific interaction.

The paper describes a feedback loop whereby introduced bark beetles are attracted to a chemical given off by fungus-infected pines, spreading a novel fungal genotype that suppresses the growth of competing fungi and increases the release of the attractant, so attracting yet more beetles to increase the dispersal of the novel genotype. The results from the study show that the novel genotype has emerged post-invasion. The paper contains a nice mix of biotechnology, pathology and insect behavioural experiments to tease out the interaction.

The implications of the findings are that a novel genotype that is more pathogenic to pine trees has evolved in the introduced range (China) and now poses a threat to the native range (North America).

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