Transcriptomics of Specialized Ant-Plant Domatia

Samples of three S. imberbis individuals were collected on Vanua Levu island in Fiji, along the Cross Island road before the bifurcation to Nabouwalu and Labasa in July 2018. Samples were immediately placed in RNAlater (Sigma‐Aldrich) until their extraction <72 h later. Plants were identified by the senior author (G.C.), following the taxonomy of Chomicki and Renner (2016b (link)) and documented by the herbarium voucher G. Chomicki, J. Aroles, A. Naikatini 50 (M). Three tissue samples per plant were collected: (1) the warty surface of the basal wall of the domatium (1 mm thickness); (2) the smooth surface in the apex cavities of the domatium (1 mm thickness); and (3) the tuber tissue under the wall surface. Tuber tissue (i.e., domatium tissue without any differentiation, shown in gray in Figure 1b) was used as a control. All individuals sampled were healthy, mature plants of a similar size (domatium diameter c. 15 cm), each inhabited by P. nagasau ants (coming from distinct ant colonies). RNA extraction was performed using a NucleoSpin RNA Plant Mini Kit (Macherey‐Nagel, Düren, Germany) following the manufacturer's protocol.