The evolutionary adaptation of wood-decay macrofungi to host gymnosperms differs from that to host angiosperms.

Abstract

Wood-decay macrofungi play a vital role in forest ecosystems by promoting nutrient cycling and soil structure, and their evolution is closely related to their host plants. This study investigates the potential evolutionary adaptation of wood-decay macrofungi to their host plants, focusing on whether these relationships differ between gymnosperms and angiosperms. While previous research has suggested non-random associations between specific fungi and plant deadwood, direct evidence of evolutionary adaptation has been lacking. Our study, conducted in a subtropical region, utilized metabarcoding techniques to identify deadwood species and associated fungi. We found significant evidence of evolutionary adaptation when considering all sampled species collectively. However, distinct patterns emerged when comparing angiosperms and gymnosperms: a significant evolutionary adaptation was observed of wood-decay macrofungi to angiosperms, but not to gymnosperms. This variation may be due to the longer evolutionary history and more stable species interactions of gymnosperms, as indicated by a higher modularity coefficient (r = .452), suggesting greater specialization. In contrast, angiosperms, being evolutionarily younger, displayed less stable and more coevolving interactions with fungi, reflected in a lower modularity coefficient (r = .387). Our findings provide the first direct evidence of differential evolutionary adaptation dynamics of these fungi to angiosperms versus gymnosperms, enhancing our understanding of forest ecosystem carbon cycling and resource management.