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Dr. Guillaume Chomicki

Contact

Email:guillaume.chomicki@gmail.com
Internet:guillaumechomicki.wordpress.com

Education

Bsc Plant Sciences, University of Manchester, First Class

Awards

2014Research Award, Society of Systematic Biologists
2014Graduate Student Research Grants, The American Society of Plant Taxonomy
2013Elected Fellow of the Linnean Society of London
2012D.H. Valentine Plant Science Programme Prize, (top plant science student), awarded by the Faculty of Life Sciences, University of Manchester
2012Conference Travel Award, awarded by the American Society of Plant Biology
2011Young Botanist Award, awarded by the Botanical Society of America
2010-2012Sainsbury Undergraduate Studentship, awarded by the Gatsby charitable Foundation for plant science (UK)
2009NTBG scholarchip for the Harvard summer course BIOS-111 (US) and travel grant

Ph.D. research

My PhD research is focusing on the evolution of ant-plant mutualisms. I integrate phylogenetics, biogeography and a range of morphological analyses to decipher the spatio-temporal build-up of these mutualisms and how morphology evolved in concert to constrain or relax the topology of ant-plant networks.


Tococa guianensis a Neotropical ant-plant which offer shelter to ants in leaf pouches

Past and continuing research

Microtubule research

Previous research has focused on the regulation of the microtubule cytoskeleton for making different cell types (Wightman‡, Chomicki‡ et al., 2013, Curr Biol). An enzyme called katanin is responsible for cutting microtubules at sites where they cross one another. The geometry of these cortical microtubules is essential for cell shape as they direct cellulose synthase which controls directional cell expansion. In Arabidopsis cotyledon, pavement cells exhibit net-like arrays while petiole cells have well-aligned arrays. The geometry of these arrays is essentially controlled by the microtubule-severing enzyme katanin. In pavement cells, severing rates are very low while they are high in petiole cells. We found that a protein called SPIRAL2 (SPR2) is responsible for regulating the activity of katanin in the different cell types. In pavement cells, SPR2 agglomerates at crossover sites which are then inaccessible to katanin. In contrast, in petiole cells, SPR2 particles constantly move along microtubules, exposing crossovers which become substrates for katanin. Thus, a one-parameter system that consists of the dynamicity of the protein SPR2 controls the formation of different microtubule arrays and thus, of distinct cell shapes.

A unique morphological adaptation in the mangrove palm (Nypa fruticans)

Mangrove plants are characterised by blatant adaptations to their habitat: aerial roots or pneumatophores which enable them to supply their root system with oxygen. No such obvious adaptation is present in Nypa fruticans, the only mangrove palm species, which is an essential element of South-East Asian mangal ecosystems. We have shown (Chomicki et al., in press, Bot J Linn Soc) that the ‘snorkel’ role is played by leaf bases in Nypa. Lenticels develop on the leaf base as the leaf ages. An unusual abscission mechanism shed the rachis and a complex aerenchyma network connects the lenticels to the roots. Moreover, age estimations suggest a long lifespan for these leaf bases which can thus supply oxygen for the roots in the long term. Since tannins accumulate as the leaf base ages, it is hypothesised that these compounds play a role in the long lifespan of these original aerating structures.

Convergent evolution in Zingiberales rhizomes

Fieldwork in Ecuador has been an opportunity to study in details the rhizome morphology of 17 Zingiberales species in 6/8 of the families of the order. A matrix of 17 characters reveals two rhizome groups that differ mainly based on two developmental parameters: branching timing and localisation. Localised, immediate branching at certain internodes results in a highly predictable geometry with a clear growth pattern while non-localised, delayed branching results in poorly predictable, non-geometric rhizome architectures. The correlated evolution of these two characters resulted in multiple switches of rhizome morphologies in the evolution of the order and thus, a high level of convergence. For more details see Chomicki (2013, Acta Botanica Gallica)

Publications

Chomicki G., Staedler Y., Schönenberger J., Renner S.S.: Partner choice through concealed floral sugar rewards evolved with the specialization of ant/plant mutualisms. New Phytologist (Accepted with minor revision 16 March 2016).

Chomicki G., Renner S.S.: Evolutionary relationships and history of the ant-epiphytic genus Squamalleria (Rubiaceae: Psychotrieae) and their taxonomic implications. PLoS ONE (in press, doi: 10.1371/journal.pone.0151317).

Chomicki G., Ward P.S., Renner S.S. (2015): Macroevolutionary assembly of ant/plant symbioses: Pseudomyrmex ants and their ant-housing plants in the Neotropics. Proceedings of the Royal Society of London B: Biological Sciences 282: 20152200.

Chomicki G., Bidel L.P.R., Ming F., Coiro M., Zhang X., Wang Y., Baissac Y., Jay-Allemand C., and S.S. Renner (2015): The velamen protects photosynthetic orchid roots against UV-B damage, and a large dated phylogeny implies multiple gains and losses of this function during the Cenozoic. New Phytologist 205(3): 1330 – 1341.

Chomicki G., and S.S. Renner (2015): Watermelon origin solved with molecular phylogenetics including Linnaean material: Another example of museomics. New Phytologist 205(2): 526 – 532.

Chomicki G., and S.S. Renner (2015): Phylogenetics and molecular-clock dating reveal the repeated evolution of ant-plants after the late Miocene in Africa and the early Miocene in Australasia and the Neotropics. New Phytologist 207: 411–424.

Bidel L.P., Chomicki G., Bonini F., Mondolot L., Soulé J., Coumans M., La Fisca P., Baissac Y., Petit V., Loiseau A. and Cerovic Z.G. (2015): Dynamics of flavonol accumulation in leaf tissues under different UV-B regimes in Centella asiatica (Apiaceae). Planta 242: 545 – 559.

Renner S.S., Chomicki G., Greuter W. (2014): Proposal to conserve the name Momordica lanata (Citrullus lanatus) (watermelon, Cucurbitaceae), with a conserved type, against Citrullus battich. Taxon 63(4): 941 – 942.

Chomicki G., Bidel L.P., Baker W.J. & Jay-Allemand C. (2014): Palm snorkelling: leaf bases as aeration structures in the mangrove palm (Nypa fruticans). Botanical Journal of the Linnean Society 174(2): 257 – 270.

Chomicki G., Bidel L.P. & Jay-Allemand C. (2014): Exodermis structure controls fungal invasion in the leafless epiphytic orchid Dendrophylax lindenii (Lindl.) Benth. ex Rolfe. Flora-Morphology, Distribution, Functional Ecology of Plants 209(2): 88 – 94.

Wightman R.*, Chomicki G.*, Kumar M., Carr P. & Turner S.R. (2013): SPIRAL2 determines plant microtubule organization by modulating microtubule severing. Current Biology 23(19): 1902 – 1907. [*Equal participation]

Chomicki, G. (2013): Analysis of rhizome morphology of the Zingiberales in Payamino (Ecuador) reveals convergent evolution of two distinct architectural strategies. Acta Botanica Gallica 160(3 – 4): 239 – 254.

Chomicki, G. (2010): Aspects de la biologie de Myrmecodia beccarii Hook f. Terra Seca 5(1): 20 – 29.

Chomicki, G. (2007): Escapade botanique dans les jardins lisboètes. Partie 2. Le Palmier 51(2).

Chomicki, G. (2007): Escapade botanique dans les jardins lisboètes. Partie 1. Le Palmier 50(1).

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Last update: 2016-04-23