Genome of an endosymbiont coupling N2 fixation to cellulolysis within protist cells in termite gut.
Termites harbor diverse symbiotic gut microorganisms, the majority of which are as yet uncultivable and their interrelationships unclear. Here, we present the complete genome sequence of the uncultured Bacteroidales endosymbiont of the cellulolytic protist Pseudotrichonympha grassii, which accounts for 70% of the bacterial cells in the gut of the termite Coptotermes formosanus. Functional annotation of the chromosome (1,114,206 base pairs) unveiled its ability to fix dinitrogen and recycle putative host nitrogen wastes for biosynthesis of diverse amino acids and cofactors, and import glucose and xylose as energy and carbon sources. Thus, nitrogen fixation and cellulolysis are coupled within the protist's cells. This highly evolved symbiotic system probably underlies the ability of the worldwide pest termites Coptotermes to use wood as their sole food.
Hongoh
Yuichi
Y
Ecomolecular Biorecycling Science Research Team, RIKEN Advanced Science Institute, Saitama 351-0198, Japan. yhongo@riken.jp
Sharma
Vineet K
VK
Prakash
Tulika
T
Noda
Satoko
S
Toh
Hidehiro
H
Taylor
Todd D
TD
Kudo
Toshiaki
T
Sakaki
Yoshiyuki
Y
Toyoda
Atsushi
A
Hattori
Masahira
M
Ohkuma
Moriya
M
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D041963:Bacteroidetes / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D002876:Chromosomes, Bacterial / Q000235:genetics; D004064:Digestive System / Q000378:metabolism / Q000382:microbiology / Q000469:parasitology; D056890:Eukaryota / Q000302:isolation & purification / Q000378:metabolism / Q000382:microbiology*; D005285:Fermentation; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D006019:Glycolysis; D020049:Isoptera / Q000378:metabolism / Q000382:microbiology* / Q000469:parasitology; D053858:Metabolic Networks and Pathways; D008969:Molecular Sequence Data; D009005:Monosaccharides / Q000378:metabolism; D009586:Nitrogen Fixation / Q000235:genetics; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D013559:Symbiosis; D014934:Wood / Q000378:metabolism
D000596:Amino Acids; D009005:Monosaccharides; D002482:Cellulose; D010088:Oxidoreductases; C029130:nitrogenase reductase