Evolution of filamentous plant pathogens: gene exchange across eukaryotic kingdoms.
Filamentous fungi and oomycetes are eukaryotic microorganisms that grow by producing networks of thread-like hyphae, which secrete enzymes to break down complex nutrients, such as wood and plant material, and recover the resulting simple sugars and amino acids by osmotrophy. These organisms are extremely similar in both appearance and lifestyle and include some of the most economically important plant pathogens . However, the morphological similarity of fungi and oomycetes is misleading because they represent some of the most distantly related eukaryote evolutionary groupings, and their shared osmotrophic growth habit is interpreted as being the result of convergent evolution . The fungi branch with the animals, whereas the oomycetes branch with photosynthetic algae as part of the Chromalveolata . In this report, we provide strong phylogenetic evidence that multiple horizontal gene transfers (HGT) have occurred from filamentous ascomycete fungi to the distantly related oomycetes. We also present evidence that a subset of the associated gene families was initially the product of prokaryote-to-fungi HGT. The predicted functions of the gene products associated with fungi-to-oomycete HGT suggest that this process has played a significant role in the evolution of the osmotrophic, filamentous lifestyle on two separate branches of the eukaryote tree.
Richards
Thomas A
TA
School of Biosciences, University of Exeter, Geoffrey Pope Building, Exeter EX4 4QD, United Kingdom.
Dacks
Joel B
JB
Jenkinson
Joanna M
JM
Thornton
Christopher R
CR
Talbot
Nicholas J
NJ
D020418:Algal Proteins / Q000145:classification / Q000235:genetics; D002352:Carrier Proteins / Q000145:classification / Q000235:genetics; D005057:Eukaryotic Cells / Q000145:classification; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000145:classification / Q000235:genetics; D005658:Fungi / Q000145:classification / Q000166:cytology / Q000235:genetics*; D022761:Gene Transfer, Horizontal; D005810:Multigene Family; D009868:Oomycetes / Q000145:classification / Q000166:cytology / Q000235:genetics*; D010802:Phylogeny; D010944:Plants / Q000382:microbiology / Q000469:parasitology
D020418:Algal Proteins; D002352:Carrier Proteins; D005656:Fungal Proteins