Diversity and cold adaptation of endophytic fungi from five dominant plant species collected from the Baima Snow Mountain, Southwest China

摘要

The diversity and cold adaptation of endophytic fungi associated with five dominant plant species collected from the Baima Snow Mountain (altitude 4,000-4,300 m), Southwest China, were investigated. A total of 604 culturable endophytic fungi were isolated from 800 stems and leaf segments. The colonization rate of endophytic fungi in the five plant species ranged from 54% to 91%, and the colonization rate of endophytic fungi in the stems was significantly higher (87%) than that in the leaves (67%) (X～2=45.172, P<0.001, chi-squared test). Based on the morphological characteristics and the ITS sequence analysis, the isolates were identified to 43 taxa, of which Cephalosporium, Sirococcus, Penicillium and Aspergillus were the dominant genera, and their relative frequencies were 14.06%, 12.58%, 9.44% and 7.95%, respectively. The Shannon-Weiner diversity indices and the Sorenson's coefficient similarity indices of the endophytic fungi from the five plant species ranged from 1.25 to 2.70 and 0.53 to 0.67, respectively. Growth temperature tests indicated that 75% of the isolates from the Baima Snow Mountain were psychrotrophs and 14% were the transitional type between psychrotrophs and mesophiles, whereas all of the isolates from the Yuanjiang Dry-hot Valley were mesophiles, which suggested that the endophytes from the Baima Snow Mountain possess a remarkable ability to adapt to cold environments.