The Baylor sequencing center has published the genome of two honey bee pathogens. Recently Baylor and collaborators published a slew of honey bee genome papers and it is great that they have also chosen to follow up on the parasites as well.
The group published the genomes of the bacteria pathogen Paenibacillus larvae and fungal pathogen Ascosphaera apis. A. apis is in the Onygenales clade which also includes the fungal human pathogens Coccidioides, Histoplasma, and Blastomyces.
Currently the genome annotation is limited to the bacterial genome where many ab initio gene prediction programs exist and no annotation is provided for A. api. We should be able to apply gene prediction parameters trained from other Onygenales fungi to get a resonable annotation. Study of this pathogenic genome may also provide insight into the evolution of this clade of fungi which contains most of the primary fungal pathogens of humans.
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. There are more layers to the relationship as a fungal parasite (Escovopsis) attacks the cultivated fungi, and a bacteria. Several researchers have studied the coevolution of these studies including Ulrich Mueller and Cameron Currie. Currie and Mueller have published several great studies describing the patterns of coevolution and the nature of the cooperation.
Continue reading Tripartate symbioses with fungi
The FGI and the Broad Institute have released the 7X genome assembly of Puccinia graminis f. sp tritici in roughly 4500 contigs. This represents the first rust fungus to be sequenced and the second Urediniomycete that has been sequenced, Sporobolomyces roseus being the first. This rust fungus is “the causal agent of stem rust, has caused serious disease of small cereal grains (wheat, barley, oat, and rye) worldwide.”
Sally Otto and colleagues have identified that populations of laboratory yeast strains convereged on diploidy in this study. This is nicely consistent with the observation that most wild strains isolated from the environment are diploid.
For example Robert Mortimer describes some properties of wild wine strains and most are found to be diploid.
A recent paper identifies “Twenty-five repetitive elements … in the genomes of the arbuscular mycorrhizal (AM) fungi Gigaspora margarita, Gig. rosea and Glomus mosseae“.
I think it will be interesting to see which of these are unique to Glomeromycota. Their findings include three gypsy-like LTR elements which are similar to those found in other organisms.
The JGI has released the Phycomyces blakesleeanus genome. This represents the second Zygomycete genome sequence that has been released in addition to Rhizopus oryzae that was released by the Broad Institute last year. We are now getting a better look at the basal fungal genomes including the Chytrids and Zygomycetes. Much more on specifics of Phycomyces biology and history are on this site run by the group organizing the genome analysis.
I find one of the most interesting things about P. blakesleeanus is its phototropism. We know light sensing is controlled, in part, by the gene white-collar 1. A homolog of this gene in Neurospora crassa is involved as an oscillator circadian rhythm. Of course many more genes are involve in pathways for light sensing including some really old proteins like phytochromes.
There will be a lot of cool analyses to do with this genome beyond phototropism. I am looking forward to seeing what gene families are unique and expanded in this species relative to the other zygomycete. It also looks like it is quite intron rich much like the Basidiomycetes, further supporting the idea that fungi had intron rich ancestors.