Abstract:

Objective: The diversity and community structure of endophytic fungi in the needles of Pinus densiflora with different incidences of Sphaeropsis sapinea were studied, and the differences of endophytic fungal diversity and community structure was analyzed, so as to provide basis for the management of pure forests of P. densiflora. Method: High-throughput sequencing technology was used to sequence the ITS1 region of the fungal rRNA gene, and further the diversity and community structure of endophytic fungi in different level of disease of P. densiflora were analyzed by using bioinformatics technology. Result: In the pure pine stands, the diversity of endophytic fungi in the asymptomatic needles of P. densiflora was higher than that of infected needles. The dominant fungi in the asymptomatic needles were Trichomerium and Phaeococomyces. The community structure changed after the infection of the pathogens. The principal coordinate analysis showed that the clustering distance within the asymptomatic endophytic fungi or the infected endophytic fungi was closer than that between the asymptomatic and the infected endophytic fungi. Compared with the asymptomatic needles, the proportion of symbiotroph fungi decreased, and the proportion of pathotrophic fungi was increased, and the proportion of saprotroph fungi accounted for a higher proportion (37.15% -65.87%) in all needles. Conclusion: In pure pine forest, the diversity and community structure of the endophytic fungi of P. densiflora are affected by S. sapinea, and the difference in the structure of endemic fungi between symptomatic needles and asymptomatic needles is significant. Fungal trophic classification confirms that saprotroph fungi and symbiotroph fungi are the main fungi in asymptomatic conifers, while pathotroph fungi are the dominant in lighter infected needles.

Key words: Pinus densiflora, Sphaeropsis sapinea, endophytic fungi, community structure