Diversity of endophytic fungi from six dominant plant species in a Pb-Zn mine wasteland in China
云南会泽铅锌矿废弃矿渣堆常见植物内生真菌多样性

The fungi which cause asymptomatic infections in living plant tissues are called endophytic fungi. They comprise diverse groups of fungi and may protect their host plants against the insect pests and phytopathogens, as well as increase hosts fitness in extreme environments. In order to document the ecological relationship between endophytic fungi and their host plants which grown in heavy metal contaminanted soils, the endophytic fungal diversity, the dominant fungi and their host specificity of six dominant plant species (Arabis hirsuta, Acacia decurrens, Symplocos paniculata, Rabbosia eriocalyx, Arenaria serpyllifolia and Rosa longicuspis) collected from the Huize Pb-Zn mine wasteland of Yunnan Province, southwest China, were investigated. A total of 495 culturable endophytic fungi were isolated from 690 stems and leaf segments of the six plant species. The isolation rate of the endophytic fungi in the six plant species ranged from 0.42 to 0.93, and the mean isolation rate was 0.72. The highest isolation rate appeared in R. eriocalyx, and the lowest isolation rate appeared in Ro. longicuspis. It was found that the isolation rate of the endophytic fungi in the stems was significantly higher than that in the leaves (P<0.05, t test) in the six plant species. Based on their morphological characteristics, the way of spore production and spore characteristics, the sporulating isolates were identified to genus level. Non-sporulating isolates were identified as mycelia sterile and sorted into different groups based on the colony surface texture, hyphal pigmentation and growth rates after two months sporulation. The fungi were identified to 20 taxa, of which Phoma and Peyronellaea were the dominant endophytic fungi. The endophytic fungal richness of the six plant species was different. The highest endophytic fungal richness appeared in Ara. hirsuta, R. eriocalyx and Ro. longicuspis, from which 13 endophytic fungal taxa were obtained. While, the lowest richness appeared in Aca. decurrens and only nine taxa were found in it. Each plant species harboured one to two dominant fungi. The dominant fungi of Ara. hirsuta, Aca. decurrens and R. eriocalyx were Phoma and Peyronellaea, the relative frequency of them were 47.22% and 27.78%, 73.33% and 16%, 48.21% and 27.68%, respectively. Alternaria was the dominant fungi of S. paniculata, the relative frequency was 46.67%. The dominant fungi of Are. serpyllifolia were Alternaria and Peyronellaea, the relative frequency was 26.74% and 25.58%, respectively. The dominant fungi of Ro. longicuspis were Phoma and Alternaria, the relative frequency was 33.34% and 15.56%, respectively. The diversity index of endophytic fungi in the six plant species ranged from 1.05 to 2.29, which was similar to the diversity index of other non-polluted environments, suggesting that there are various heavy metal-resistant endophytic fungi in heavy metal contaminated areas. Besides, the diversity index of endophytic fungi from stems was 0.98