Biodiversity Science ›› 2016, Vol. 24 ›› Issue (9): 1056-1061.doi: 10.17520/biods.2016143

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Frequency dependent fitness in different evolved Escherichia coli lines

Chuan Ni, Biru Zhu, Dayong Zhang*()   

  1. Key Laboratory for Biodiversity Science and Ecological Engineering of Ministry of Education, Beijing Normal University, Beijing 100875
  • Online:2016-10-09
  • Zhang Dayong

Differences in fitness between two species or genotypes is usually assumed to be constant when competition experiments are used to measure relative fitness in evolutionary experiments. However, interactions between competitors may lead to frequency-dependence in fitness. We measured the relative fitness of two types of evolved lines of Escherichia coli under different initial relative frequencies to analyze the effects of initial relative frequency on relative fitness. Competed with the low nitrogen evolved lines, the high nitrogen evolved lines displayed increased relative fitness with decreased initial relative frequency, which suggests negative frequency dependence. Both types did not grow in the filtrate from high nitrogen evolved lines, but grew in the filtrate from low nitrogen evolved lines. However, the number of cell doublings of the high nitrogen evolved lines was three times higher than that of the low nitrogen evolved lines. One probable explanation for the negative frequency dependent fitness was that the low nitrogen evolved lines had weaker resource competitive ability and could not sufficiently use resources. Another explanation was that the high nitrogen evolved lines could use some metabolites produced by the low nitrogen evolved lines, which suggests the existence of cross-feeding interaction. Different interactions may lead to different relationships between relative fitness and initial relative frequency. Therefore, we need to account for the effects of initial relative frequency on relative fitness to more accurately measure fitness in evolutionary experiments.

Key words: competition experiment, initial relative frequency, cross-feeding interaction, allelopathic interaction

Table 1

The relative fitness of N+ lines with different initial relative frequencies when comparing with N- lines. One sample t-tests were used and the null hypothesis was the relative fitness equaled to one. Tukey HSD test was used to do multiple comparisons for the relative fitness with different initial relative frequencies, and the different letters on the upper right indicate statistically significant difference."

Initial relative frequency of N+
Relative fitness (mean±SE, n = 10)
t 统计量
0.01 1.5176 ± 0.0760a 6.812 9 <0.001
0.1 1.2992 ± 0.0345b 8.681 9 <0.001
0.5 1.0829 ± 0.0188c 4.414 9 0.002
0.9 1.0814 ± 0.0241c 3.384 9 0.008
0.99 1.0750 ± 0.0282c 2.658 9 0.026

Fig. 1

The relationship between relative fitness and initial relative frequency of N+ lines (A), and the number of cell doublings (D) of two types of evolved Escherichia coli lines in two different filtrates (B). (A) The black dots show the mean relative fitness of N+ lines comparing with N- lines, and the error bars show SE (n =10). The curve indicates the regression model, whose equation and statistical significance are showed upper right. (B) Data show mean ± SE (n = 10). N+F and N-F indicate filtrate prepared from 24 h cultures of N+ lines and N- lines, respectively. *** P < 0.001, and NS indicates P > 0.05 (two independent sample t-tests)."

[1] Ayala FJ (1971) Competition between species: frequency dependence. Science, 171, 820-824.
[2] Chao L, Levin BR (1981) Structured habitats and the evolution of anticompetitor toxins in bacteria. Proceedings of the National Academy of Sciences, USA, 78, 6324-6328.
[3] Debenedictis PA (1977) Meaning and measurement of frequency-dependent competition. Ecology, 58, 158-166.
[4] Estrela S, Gudelj I (2010) Evolution of cooperative cross-feeding could be less challenging than originally thought. PLoS ONE, 5, e14121.
[5] Greig D, Travisano M (2008) Density-dependent effects on allelopathic interactions in yeast. Evolution, 62, 521-527.
[6] Harpole WS, Suding KN (2007) Frequency-dependence stabilizes competitive interactions among four annual plants. Ecology Letters, 10, 1164-1169.
[7] Helling RB, Vargas CN, Adams J (1987) Evolution of Escherichia coli during growth in a constant environment. Genetics, 116, 349-358.
[8] Kerswell KJ, Burd M (2012) Frequency-dependent and density-dependent larval competition between life-history strains of a fly, Lucilia cuprina. Ecological Entomology, 37, 109-116.
[9] Lenski RE (1988) Experimental studies of pleiotropy and epistasis in Escherichia coli. I. Variation in competitive fitness among mutants resistant to virus T4. Evolution, 42, 425-432.
[10] Lenski RE, Rose MR, Simpson SC, Tadler SC (1991) Long-term experimental evolution in Escherichia coli 1: adaptation and divergence during 2000 generations. The American Naturalist, 138, 1315-1341.
[11] Molofsky J, Bever JD (2002) A novel theory to explain species diversity in landscapes: positive frequency dependence and habitat suitability. Proceedings of the Royal Society B: Biological Sciences, 269, 2389-2393.
[12] Molofsky J, Bever JD, Antonovics J (2001) Coexistence under positive frequency dependence. Proceedings of the Royal Society B: Biological Sciences, 268, 273-277.
[13] Ni C (2011) The Experimental Evolution of Escherichia coli in Nitrogen Limited Environment. PhD dissertation, Beijing Normal University, Beijing. (in Chinese with English abstract)
[倪川 (2011) 大肠杆菌在缺氮环境下的实验进化. 博士学位论文, 北京师范大学, 北京.]
[14] Pfeiffer T, Bonhoeffer S (2004) Evolution of cross-feeding in microbial populations. The American Naturalist, 163, E126-E135.
[15] R Core Team (2015) R: A Language and Environment for Statistical Computing.
[16] Rendueles O, Amherd M, Velicer GJ (2015) Positively frequency-dependent interference competition maintains diversity and pervades a natural population of cooperative microbes. Current Biology, 25, 1673-1681.
[17] Ribeck N, Lenski RE (2015) Modeling and quantifying frequency-dependent fitness in microbial populations with cross-feeding interactions. Evolution, 69, 1313-1320.
[18] Rosenzweig RF, Sharp RR, Treves DS, Adams J (1994) Microbial evolution in a simple unstructured environment: genetic differentiation in Escherichia coli. Genetics, 137, 903-917.
[19] Rozen DE, Lenski RE (2000) Long-term experimental evolution in Escherichia coli VIII: dynamics of a balanced polymorphism. The American Naturalist, 155, 24-35.
[20] Tilman D, Wedin D (1991) Plant traits and resource reduction for 5 grasses growing on a nitrogen gradient. Ecology, 72, 685-700.
[21] Treves DS, Manning S, Adams J (1998) Repeated evolution of an acetate-crossfeeding polymorphism in long-term populations of Escherichia coli. Molecular Biology and Evolution, 15, 789-797.
[22] Turner PE, Souza V, Lenski RE (1996) Tests of ecological mechanisms promoting the stable coexistence of two bacterial genotypes. Ecology, 77, 2119-2129.
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[1] Liu Hou-fen and Cai Yao-yuan. Comparative Anatomical Study on Regenerated Roots from Explants Induced by Triacontanol[J]. Chin Bull Bot, 1984, 2(23): 66 -68 .
[2] AO Tao-, LIAO Xiao-Jia-, XU Wei-, LIU Ai-Zhong. Identification and Characterization of GATA Gene Family in Castor Bean (Ricinus communis)[J]. Plant Diversity, 2015, 37(4): 453 -462 .
[3] Zhang Jinquan. Plant Geography Study and Symposium for Chinese Teachers Universities and Colleges Was Held in Guangzhou[J]. Chin J Plan Ecolo, 1983, 7(1): 85 .
[4] Guo Yu-qing, Xie Shu-qi, Li Jiang-song. A New Species of the Genus Amphora (Bacillariophyta)[J]. J Syst Evol, 1997, 35(3): 273 -274 .
[5] XU Yuan-Jie, CHEN Ya-Ning, LI Wei-Hong, FU Ai-Hong, MA Xiao-Dong, GUI Dong-Wei, CHEN Ya-Peng. Distribution pattern and environmental interpretation of plant species diversity in the mountainous region of Ili River Valley, Xinjiang, China[J]. Chin J Plan Ecolo, 2010, 34(10): 1142 -1154 .
[6] WANG Ai-Ying , , JIANG Yan-Juan , , HAO Guang-You , , CAO Kun-Fang.

The Effect of Seasonal Drought to Plant Hydraulics and Photosynthesis of Three Dominant Evergreen Tree Species in Seasonal Tropical Rainforest of
Xishuangbanna Limestone Area

[J]. Plant Diversity, 2008, 30(03): 325 -332 .
[7] Congming Lu. Photosynthesis for Food, Fuel and the Future[J]. J Integr Plant Biol, 2010, 52(8): 694 -697 .
[8] CHENG Ke-Wu, ZANG Run-Guo. Advances in species endangerment assessment[J]. Biodiv Sci, 2004, 12(5): 534 -540 .
[9] . [J]. Chin Bull Bot, 1994, 11(专辑): 44 .
[10] Yuexia Wang,Yi Jin,Chuping Wu,Dongming Wong,Lixing Ye,Deliang Chen,Jianping Yu,Jinliang Liu,Lei Zhong,Mingjian Yu. Taxonomic and phylogenetic α and β diversities of major subtropical forest community types in Zhejiang Province[J]. Biodiv Sci, 2016, 24(8): 863 -874 .