Endophytic fungi and silica content of different bamboo species in giant panda diet

The giant panda (Ailuropoda melanoleuca), one of the most threatened mammalian species in the world, has adapted to herbivorous diet consisting mainly of bamboo (Poaceae: Bambusoidea). The most acute threats to the survival of the giant panda are habitat loss and fragmentation. However, changes in habitat may influence also the quality of giant panda diet through the bamboo species composition as well as their symbiotic leaf endophytes and plant chemical properties. Here we explore species composition and frequency of endophytic fungi and silica content in different bamboo species in the range of giant panda habitat in relation to panda food preference. Silica content of the bamboos varied from 3.7 g/kg to 45.7 g/kg and did not correlate with panda preference and altitudinal gradient. Systemic and vertically in seeds transmitted fungal endophytes or bacterial endophytes were not detected in bamboo leaves. Nearly half of the identified endophytic fungi belonged to genus Arthrinium. Pandas preferred bamboo species naturally occurring in higher altitudes. Furthermore, the total amount of endophytes tended to be lower in samples collected from bamboos in higher altitudes. This draws attention to the importance of more detailed studies on the endophytic fungi-bamboo-panda trophic interactions and the effect of land use and climate change on conservation programs of giant panda.