@article{14479,
  abstract     = {In animals, parasitic infections impose significant fitness costs.1,2,3,4,5,6 Infected animals can alter their feeding behavior to resist infection,7,8,9,10,11,12 but parasites can manipulate animal foraging behavior to their own benefits.13,14,15,16 How nutrition influences host-parasite interactions is not well understood, as studies have mainly focused on the host and less on the parasite.9,12,17,18,19,20,21,22,23 We used the nutritional geometry framework24 to investigate the role of amino acids (AA) and carbohydrates (C) in a host-parasite system: the Argentine ant, Linepithema humile, and the entomopathogenic fungus, Metarhizium brunneum. First, using 18 diets varying in AA:C composition, we established that the fungus performed best on the high-amino-acid diet 1:4. Second, we found that the fungus reached this optimal diet when given various diet pairings, revealing its ability to cope with nutritional challenges. Third, we showed that the optimal fungal diet reduced the lifespan of healthy ants when compared with a high-carbohydrate diet but had no effect on infected ants. Fourth, we revealed that infected ant colonies, given a choice between the optimal fungal diet and a high-carbohydrate diet, chose the optimal fungal diet, whereas healthy colonies avoided it. Lastly, by disentangling fungal infection from host immune response, we demonstrated that infected ants foraged on the optimal fungal diet in response to immune activation and not as a result of parasite manipulation. Therefore, we revealed that infected ant colonies chose a diet that is costly for survival in the long term but beneficial in the short term—a form of collective self-medication.},
  author       = {Csata, Eniko and Perez-Escudero, Alfonso and Laury, Emmanuel and Leitner, Hanna and Latil, Gerard and Heinze, Juerge and Simpson, Stephen and Cremer, Sylvia and Dussutour, Audrey},
  issn         = {1879-0445},
  journal      = {Current Biology},
  number       = {4},
  pages        = {902--909.e6},
  publisher    = {Elsevier},
  title        = {{Fungal infection alters collective nutritional intake of ant colonies}},
  doi          = {10.1016/j.cub.2024.01.017},
  volume       = {34},
  year         = {2024},
}

@unpublished{14478,
  abstract     = {Entire chromosomes are typically only transmitted vertically from one generation to the next. The horizontal transfer of such chromosomes has long been considered improbable, yet gained recent support in several pathogenic fungi where it may affect the fitness or host specificity. To date, it is unknown how these transfers occur, how common they are and whether they can occur between different species. In this study, we show multiple independent instances of horizontal transfers of the same accessory chromosome between two distinct strains of the asexual entomopathogenic fungus<jats:italic>Metarhizium robertsii</jats:italic>during experimental co-infection of its insect host, the Argentine ant. Notably, only the one chromosome – but no other – was transferred from the donor to the recipient strain. The recipient strain, now harboring the accessory chromosome, exhibited a competitive advantage under certain host conditions. By phylogenetic analysis we further demonstrate that the same accessory chromosome was horizontally transferred in a natural environment between<jats:italic>M. robertsii</jats:italic>and another congeneric insect pathogen,<jats:italic>M. guizhouense</jats:italic>. Hence horizontal chromosome transfer is not limited to the observed frequent events within species during experimental infections but also occurs naturally across species. The transferred accessory chromosome contains genes that might be involved in its preferential horizontal transfer, encoding putative histones and histone-modifying enzymes, but also putative virulence factors that may support its establishment. Our study reveals that both intra- and interspecies horizontal transfer of entire chromosomes is more frequent than previously assumed, likely representing a not uncommon mechanism for gene exchange.</jats:p><jats:sec><jats:title>Significance Statement</jats:title><jats:p>The enormous success of bacterial pathogens has been attributed to their ability to exchange genetic material between one another. Similarly, in eukaryotes, horizontal transfer of genetic material allowed the spread of virulence factors across species. The horizontal transfer of whole chromosomes could be an important pathway for such exchange of genetic material, but little is known about the origin of transferable chromosomes and how frequently they are exchanged. Here, we show that the transfer of accessory chromosomes - chromosomes that are non-essential but may provide fitness benefits - is common during fungal co-infections and is even possible between distant pathogenic species, highlighting the importance of horizontal gene transfer via chromosome transfer also for the evolution and function of eukaryotic pathogens.},
  author       = {Habig, Michael and Grasse, Anna V and Müller, Judith and Stukenbrock, Eva H. and Leitner, Hanna and Cremer, Sylvia},
  booktitle    = {bioRxiv},
  title        = {{Frequent horizontal chromosome transfer between asexual fungal insect pathogens}},
  doi          = {10.1101/2023.09.18.558174},
  year         = {2023},
}

@article{1852,
  abstract     = {To control morphogenesis, molecular regulatory networks have to interfere with the mechanical properties of the individual cells of developing organs and tissues, but how this is achieved is not well known. We study this issue here in the shoot meristem of higher plants, a group of undifferentiated cells where complex changes in growth rates and directions lead to the continuous formation of new organs [1, 2]. Here, we show that the plant hormone auxin plays an important role in this process via a dual, local effect on the extracellular matrix, the cell wall, which determines cell shape. Our study reveals that auxin not only causes a limited reduction in wall stiffness but also directly interferes with wall anisotropy via the regulation of cortical microtubule dynamics. We further show that to induce growth isotropy and organ outgrowth, auxin somehow interferes with the cortical microtubule-ordering activity of a network of proteins, including AUXIN BINDING PROTEIN 1 and KATANIN 1. Numerical simulations further indicate that the induced isotropy is sufficient to amplify the effects of the relatively minor changes in wall stiffness to promote organogenesis and the establishment of new growth axes in a robust manner.},
  author       = {Sassi, Massimiliano and Ali, Olivier and Boudon, Frédéric and Cloarec, Gladys and Abad, Ursula and Cellier, Coralie and Chen, Xu and Gilles, Benjamin and Milani, Pascale and Friml, Jirí and Vernoux, Teva and Godin, Christophe and Hamant, Olivier and Traas, Jan},
  journal      = {Current Biology},
  number       = {19},
  pages        = {2335 -- 2342},
  publisher    = {Cell Press},
  title        = {{An auxin-mediated shift toward growth isotropy promotes organ formation at the shoot meristem in Arabidopsis}},
  doi          = {10.1016/j.cub.2014.08.036},
  volume       = {24},
  year         = {2014},
}