Blaxter, Mark et al. (2015) International Worm Meeting "The Caenorhabditis Genomes Project."

Stevens, Lewis, Chandrasekar, Sinduja, Koutsovoulos, Georgios, Blaxter, Mark

[International Worm Meeting, 2015]

The sequencing of the genome of Caenorhabditis elegans remains one of the milestones of modern biology, and this genome sequence is the essential backdrop to a vast body of work on this key model organism. "Nothing in biology makes sense except in the light of evolution" (Dobzhansky) and thus it is clear that complete understanding of C. elegans will only be achieved when it is placed in an evolutionary context. While several additional Caenorhabditis genomes have been published or made available, a recent surge in the number of available species in culture makes the determination of the genomes of all the species in the genus a timely and rewarding project.We have initiated the Caenorhabditis Genomes Project. From material supplied by collaborators we have so far generated raw Illumina short-insert data for sixteen species. Where possible we have also generated mixed stage stranded RNASeq data for annotation. The data are being made publicly available as early as possible (warts-and-all) through a dedicated genome website at htttp://caenorhabditis.bio.ed.ac.uk, and completed genomes and annotations will be deposited in WormBase as mature assemblies emerge. We welcome additional collaborators to the CGP, whether to assemble new genomes or to delve into the evolutionary history of favourite gene sets and systems.Species sequenced thus far in Edinburgh: Caenorhabditis afra, Caenorhabditis castelli, Caenorhabditis doughertyi, Caenorhabditis guadeloupensis, Caenorhabditis macrosperma, Caenorhabditis nouraguensis, Caenorhabditis plicata, Caenorhabditis virilis, Caenorhabditis wallacei, Caenorhabditis sp. 1, Caenorhabditis sp. 5, Caenorhabditis sp. 21, Caenorhabditis sp. 26, Caenorhabditis sp. 31, Caenorhabditis sp. 32, Caenorhabditis sp. 38, Caenorhabditis sp. 39, Caenorhabditis sp. 40, Caenorhabditis sp. 43.[Samples have been supplied by Aurelien Richaud, Marie-Anne Felix, Christian Braendle, Michael Alion, Piero Lamelza].

Burns, Andrew et al. (2021) International Worm Meeting "Selective Control of Parasitic Nematodes with Bioactivated Nematicides"

Ross, Rachel, Hu, Chun, Castelli, Jack, Snider, Jamie, Palmeira, Bruna, Vaidya, Aditya, Lautens, Mark, Volpatti, Jonathan, Zasada, Inga, Stagljar, Igor, Kitner, Megan, Redman, Elizabeth, Dowling, James, MacParland, Sonya, Cowen, Leah, Xiao, Qi, Finney, Constance, Cutler, Sean, Marwah, Sagar, Burns, Andrew, Tiefenbach, Jens, Puumala, Emily, Krause, Henry, Meyer, Susan, MacDonald, Margaret, Chung, Sai, Roy, Peter, Gilleard, John

[International Worm Meeting, 2021]

Global food security is threatened as the world amasses 10 billion people amid limited arable land. While nematode pests are a major barrier to agricultural intensification, most traditional nematicides are now banned because of poor nematode-selectivity, leaving farmers with inadequate controls. Here, we describe a screen carried out in the model nematode Caenorhabditis elegans that enriches for selective nematicides by identifying molecules that are bioactivated by cytochrome P450s, which are phylogenetically diverse. We identify a family of structures, called nemactivins, that are robustly bioactivated to a toxic metabolite selectively in nematodes. At low parts-per-million concentrations, nemactivins perform comparably well with commercial nematicides at controlling infection by the world's most destructive plant-parasitic nematode Meloidogyne incognita. Hence, nemactivins are first-in-class bioactivated nematicides that provide much needed nematode-selectivity.

Anaid Diaz et al. (2010) Evolutionary Biology of Caenorhabditis and Other Nematodes "DOES THE COST OF PHENOTYPIC PLASTICITY KEEP THE JACK OF ALL TRADES FROM BEING A MASTER OF ANY? AN EXPERIMENT ON Caenorhabditis remanei"

Anaid Diaz, Jan Lindstrom, Daniel T. Haydon

[Evolutionary Biology of Caenorhabditis and Other Nematodes, 2010]

Virtually all organisms live in a heterogeneous environment. It is commonly assumed that phenotypic plasticity is associated with environments variable in space and/or time, and that such a 'Jack of all trades' genotype would do better than a fixed genotype. On the other hand, a genotype with phenotypic plasticity is expected do worse in a constant environment than a fixed would. The cost of maintaining phenotypic plasticity is commonly associated with the maintenance and production of genetic and cellular machinery to detect and produce the best phenotype for the environment. Although the idea of the cost of maintaining phenotypic responses in a constant environment is widely recognised, it has not been demonstrated experimentally. We addressed this question by using long-term selection experiments on a gonochoristic nematode species (Caenorhabditis remanei). Initially, replicates of worms were maintained for 50 generations under two temperature regimes: constant temperature (mean 15C) and fluctuating environment with the same mean but temperature fluctuating between 5 and 25C every 12 hours. The objective of this experiment was to select for individuals with different levels of plasticity. Plasticity levels were measured by comparing the ability of a line to maintain high fitness across a temperature gradient. After 50 generations in each environment, populations were transposed between these environments. The objective was to compare differences in fitness of individuals from the two regimes before and after the selection experiment. Comparisons of fitness across the environments will enable to determine if selection for plasticity is costly in a constant environment, and if specialisation to a constant environment carries a cost when transferred to a fluctuating environment. The results of the first experiment showed changes in fitness across temperatures; worms from a fluctuating environment showed wider thermal breath compared to worms selected for a constant environment. This suggests that phenotypic plasticity was favoured in a fluctuating environment and it had some genetic basis. Comparisons of fitness before and after the selection experiment showed that increased phenotypic plasticity potentially incurred a fitness cost. Worms cultured in a fluctuating environment for 50 generations showed reduced fitness when cultured in a constant environment compared to worms in a constant environment at the beginning of the experiment. However, worms cultured in the constant regime and moved to the fluctuating environment showed no differences with worms in a fluctuating environment at the beginning of the experiment. These results suggest that, for this system, there is a potential cost of adapting via phenotypic plasticity but there is not a cost for becoming a fixed genotype.