A new social gene in Dictyostelium discoideum, chtB

BMC Evolutionary Biology

Joan E Strassmann²  David C Queller²  Gad Shaulsky⁴  Adam Kuspa³  Lorenzo A Santorelli¹ 

[1] Present address: Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK;Biology Department, Washington University in St. Louis, St. Louis, MO, 63130, USA;Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA;Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA

关键词: chtB;    Pre-spore marker;    D. discoideum;    Social evolution;    Cheating behavior;   

Others  :  1130393
DOI  :  10.1186/1471-2148-13-4

 received in 2012-06-07, accepted in 2012-11-29,  发布年份 2013

【 摘 要 】

Background

Competitive social interactions are ubiquitous in nature, but their genetic basis is difficult to determine. Much can be learned from single gene knockouts in a eukaryote microbe. The mutants can be competed with the parent to discern the social impact of that specific gene. Dictyostelium discoideum is a social amoeba that exhibits cooperative behavior in the construction of a multicellular fruiting body. It is a good model organism to study the genetic basis of cooperation since it has a sequenced genome and it is amenable to genetic manipulation. When two strains of D. discoideum are mixed, a cheater strain can exploit its social partner by differentiating more spore than its fair share relative to stalk cells. Cheater strains can be generated in the lab or found in the wild and genetic analyses have shown that cheating behavior can be achieved through many pathways.

Results

We have characterized the knockout mutant chtB, which was isolated from a screen for cheater mutants that were also able to form normal fruiting bodies on their own. When mixed in equal proportions with parental strain cells, chtB mutants contributed almost 60% of the total number of spores. To do so, chtB cells inhibit wild type cells from becoming spores, as indicated by counts and by the wild type cells’ reduced expression of the prespore gene, cotB. We found no obvious fitness costs (morphology, doubling time in liquid medium, spore production, and germination efficiency) associated with the cheating ability of the chtB knockout.

Conclusions

In this study we describe a new gene in D. discoideum, chtB, which when knocked out inhibits the parental strain from producing spores. Moreover, under lab conditions, we did not detect any fitness costs associated with this behavior.

【 授权许可】

   
2013 Santorelli et al.; licensee BioMed Central Ltd.

【 图 表 】

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