The Hyphal Tip: Fungal Genomes and Comparative Genomics

Today, I would like to share the news about the publication of the Laccaria bicolor genome. This is the first mycorrhizal symbiotic genome published in the Nature journal. The title is "The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis". The team consisteing of more than 60 researchers from 16 institutions have revealed the interaction between plant and fungi. For complete publication and additional

I read this blurb in the New Scientist about a PNAS paper (subscription required for next 6 months) on how hive beetles (Aethina tumida) are able to infest bee hives by throwing off the bees because they are producing isopentyl acetate which is thought to be produced and used by bees to signal an alarm.

A paper in Nature this week describes how a few mutations can alter the interactions between species in a biofilm from competitive to cooperative system. This is a great study that goes from start to finish on studying community interactions, looking at an evolved phenotype, and understanding the genetic and physiological basis for the adaptation. Acinetobacter sp. and Pseudomonas putida were raised in a carbon-limited environment with only benzyl alcohol as the carbon source. Acinetobacter can processes the benzyl alcohol, while P. putida is unable to. Acinetobacter takes up the bezyl alcohol and secretes benzoate that P. putida can then use as a carbon source. The research group propagated these in chemostats and looked at different starting concentrations of the organisms. They found that evolved P. putida had a different morphology and did several experiments to determine the relative fitness of the derived and ancestral genotype. They went on to also map the mutations in P. putida and found two independent mutations in wapH (I think this is the right gene)—a gene involved in lipopolysaccharide (LPS) biosynthesis. They then engineered the ancestral strain to have a mutation in P. putida and found the rough colony phenotype morphology indistinguishable from the strain derived from experimental evolution. There are various evolutionary and niche adaptation implications arising from this study. One application to mycology is to how lichens evolved in that an algael cell and a fungal cell must communicate and cooperate.

Ants, fungi, and bacteria I have to admit that I am fascinated by co-evolution of symbiotic and mutalistic systems. A review by Richard Robinson gives an overview. A great example is the mutalism between ants and fungi where the ants cultivate the fungi for food.