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The genome sequence of the leaf-cutter ant Atta cephalotes reveals insights into its obligate symbiotic lifestyle.

Suen G, Teiling C, Li L, Holt C, Abouheif E, Bornberg-Bauer E, Bouffard P, Caldera EJ, Cash E, Cavanaugh A, Denas O, Elhaik E, Favé MJ, Gadau J, Gibson JD, Graur D, Grubbs KJ, Hagen DE, Harkins TT, Helmkampf M, Hu H, Johnson BR, Kim J, Marsh SE, Moeller JA, Muñoz-Torres MC, Murphy MC, Naughton MC, Nigam S, Overson R, Rajakumar R, Reese JT, Scott JJ, Smith CR, Tao S, Tsutsui ND, Viljakainen L, Wissler L, Yandell MD, Zimmer F, Taylor J, Slater SC, Clifton SW, Warren WC, Elsik CG, Smith CD, Weinstock GM, Gerardo NM, Currie CR - PLoS Genet. (2011)

Bottom Line: Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition.These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus), a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus), and the absence of a hexamerin (which sequesters amino acids during larval development in other insects).Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of host-microbe symbioses.

View Article: PubMed Central - PubMed

Affiliation: Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America. gsuen@wisc.edu

ABSTRACT
Leaf-cutter ants are one of the most important herbivorous insects in the Neotropics, harvesting vast quantities of fresh leaf material. The ants use leaves to cultivate a fungus that serves as the colony's primary food source. This obligate ant-fungus mutualism is one of the few occurrences of farming by non-humans and likely facilitated the formation of their massive colonies. Mature leaf-cutter ant colonies contain millions of workers ranging in size from small garden tenders to large soldiers, resulting in one of the most complex polymorphic caste systems within ants. To begin uncovering the genomic underpinnings of this system, we sequenced the genome of Atta cephalotes using 454 pyrosequencing. One prediction from this ant's lifestyle is that it has undergone genetic modifications that reflect its obligate dependence on the fungus for nutrients. Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition. These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus), a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus), and the absence of a hexamerin (which sequesters amino acids during larval development in other insects). Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of host-microbe symbioses.

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Orthology analysis of the Atta cephalotes predicted peptide sequences (green) against the proteomes of the fly Drosophila melanogaster (blue), the wasp Nasonia vitripennis (red), and the honey bee Apis mellifera (yellow).
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pgen-1002007-g002: Orthology analysis of the Atta cephalotes predicted peptide sequences (green) against the proteomes of the fly Drosophila melanogaster (blue), the wasp Nasonia vitripennis (red), and the honey bee Apis mellifera (yellow).

Mentions: A set of shared orthologs was determined among A. cephalotes, A. mellifera, N. vitripennis, and D. melanogaster (Figure 2). A total of 5,577 orthologs were found conserved across all four insect genomes, with an additional 1,363 orthologs conserved across the three hymenopteran genomes. A further, 599 orthologs were conserved between A. cephalotes and A. mellifera, perhaps indicating genes that are specific to a eusocial lifestyle. We also found 9,361 proteins that are unique to A. cephalotes, representing over half of its predicted proteome. These proteins likely include those specific to ants or to A. cephalotes.


The genome sequence of the leaf-cutter ant Atta cephalotes reveals insights into its obligate symbiotic lifestyle.

Suen G, Teiling C, Li L, Holt C, Abouheif E, Bornberg-Bauer E, Bouffard P, Caldera EJ, Cash E, Cavanaugh A, Denas O, Elhaik E, Favé MJ, Gadau J, Gibson JD, Graur D, Grubbs KJ, Hagen DE, Harkins TT, Helmkampf M, Hu H, Johnson BR, Kim J, Marsh SE, Moeller JA, Muñoz-Torres MC, Murphy MC, Naughton MC, Nigam S, Overson R, Rajakumar R, Reese JT, Scott JJ, Smith CR, Tao S, Tsutsui ND, Viljakainen L, Wissler L, Yandell MD, Zimmer F, Taylor J, Slater SC, Clifton SW, Warren WC, Elsik CG, Smith CD, Weinstock GM, Gerardo NM, Currie CR - PLoS Genet. (2011)

Orthology analysis of the Atta cephalotes predicted peptide sequences (green) against the proteomes of the fly Drosophila melanogaster (blue), the wasp Nasonia vitripennis (red), and the honey bee Apis mellifera (yellow).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3037820&req=5

pgen-1002007-g002: Orthology analysis of the Atta cephalotes predicted peptide sequences (green) against the proteomes of the fly Drosophila melanogaster (blue), the wasp Nasonia vitripennis (red), and the honey bee Apis mellifera (yellow).
Mentions: A set of shared orthologs was determined among A. cephalotes, A. mellifera, N. vitripennis, and D. melanogaster (Figure 2). A total of 5,577 orthologs were found conserved across all four insect genomes, with an additional 1,363 orthologs conserved across the three hymenopteran genomes. A further, 599 orthologs were conserved between A. cephalotes and A. mellifera, perhaps indicating genes that are specific to a eusocial lifestyle. We also found 9,361 proteins that are unique to A. cephalotes, representing over half of its predicted proteome. These proteins likely include those specific to ants or to A. cephalotes.

Bottom Line: Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition.These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus), a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus), and the absence of a hexamerin (which sequesters amino acids during larval development in other insects).Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of host-microbe symbioses.

View Article: PubMed Central - PubMed

Affiliation: Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America. gsuen@wisc.edu

ABSTRACT
Leaf-cutter ants are one of the most important herbivorous insects in the Neotropics, harvesting vast quantities of fresh leaf material. The ants use leaves to cultivate a fungus that serves as the colony's primary food source. This obligate ant-fungus mutualism is one of the few occurrences of farming by non-humans and likely facilitated the formation of their massive colonies. Mature leaf-cutter ant colonies contain millions of workers ranging in size from small garden tenders to large soldiers, resulting in one of the most complex polymorphic caste systems within ants. To begin uncovering the genomic underpinnings of this system, we sequenced the genome of Atta cephalotes using 454 pyrosequencing. One prediction from this ant's lifestyle is that it has undergone genetic modifications that reflect its obligate dependence on the fungus for nutrients. Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition. These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus), a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus), and the absence of a hexamerin (which sequesters amino acids during larval development in other insects). Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of host-microbe symbioses.

Show MeSH
Related in: MedlinePlus