Pu Yuanshu, Naikatini Alivereti, Pérez-Escobar Oscar Alejandro, Silber Martina, Renner Susanne S, Chomicki Guillaume
German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Leipzig Germany.
South Pacific Regional Herbarium Institute of Applied Sciences The University of the South Pacific Suva Fiji.
Ecol Evol. 2021 Oct 26;11(22):15882-15895. doi: 10.1002/ece3.8258. eCollection 2021 Nov.
Farming of fungi by ants, termites, or beetles has led to ecologically successful societies fueled by industrial-scale food production. Another type of obligate insect agriculture in Fiji involves the symbiosis between the ant and epiphytes in the genus (Rubiaceae) that the ants fertilize, defend, harvest, and depend on for nesting. All farmed form tubers (domatia) with preformed entrance holes and complex cavity networks occupied by . . The inner surface of the domatia consists of smooth-surfaced walls where the ants nest and rear their brood, and warty-surfaced walls where they fertilize their crop by defecation. Here, we use RNA sequencing to identify gene expression patterns associated with the smooth versus warty wall types. Since wall differentiation occurred in the most recent common ancestor of all farmed species of , our study also identifies genetic pathways co-opted following the emergence of agriculture. Warty-surfaced walls show many upregulated genes linked to auxin transport, root development, and nitrogen transport consistent with their root-like function; their defense-related genes are also upregulated, probably to protect these permeable areas from pathogen entry. In smooth-surfaced walls, genes functioning in suberin and wax biosynthesis are upregulated, contributing to the formation of an impermeable ant-nesting area in the domatium. This study throws light on a number of functional characteristics of plant farming by ants and illustrates the power of genomic studies of symbiosis.
蚂蚁、白蚁或甲虫对真菌的养殖造就了因工业化规模的食物生产而繁荣的生态社会。斐济另一种专性昆虫农业涉及蚂蚁与茜草科（Rubiaceae）中某些附生植物之间的共生关系，蚂蚁为这些附生植物施肥、提供保护、进行采收，并依赖它们筑巢。所有被养殖的附生植物都会形成带有预先形成的入口孔和由[具体生物]占据的复杂腔室网络的块茎（虫瘿）。虫瘿的内表面由光滑壁和瘤状壁组成，蚂蚁在光滑壁处筑巢和养育幼虫，在瘤状壁处通过排便为其作物施肥。在这里，我们使用RNA测序来鉴定与光滑壁和瘤状壁类型相关的基因表达模式。由于壁的分化发生在所有被养殖的[植物属]物种的最近共同祖先中，我们的研究还确定了农业出现后被采用的遗传途径。瘤状壁显示出许多与生长素运输、根系发育和氮运输相关的上调基因，与其类似根的功能一致；它们与防御相关的基因也上调了，可能是为了保护这些可渗透区域免受病原体侵入。在光滑壁中，参与木栓质和蜡生物合成的基因上调，有助于在虫瘿中形成一个不可渗透的蚂蚁筑巢区域。这项研究揭示了蚂蚁养殖植物的一些功能特征，并说明了共生基因组研究的作用。
