Seasonal Variations in the Diversity of Endophytic and Epiphytic Fungal Communities in Pteroceltis tatarinowii

Purpose To investigate the community structure and seasonal characteristics of endophytic and epiphytic fungi in Pteroceltis tatarinowii, exploring the relationships between communities and the potential reasons for the observed diversity.

Methods Healthy twigs of wild P. tatarinowii were collected in different seasons. Endophytic and epiphytic fungi were isolated using tissue separation and oscillation washing plate methods. The culture, identification and community diversity analysis of fungi were carried out.

Results The fungal communities of P. tatarinowii were predominantly composed of Ascomycota, accounting for 94.78% and 87.62% of endophytic and epiphytic fungi, respectively. Endophytic fungi were primarily comprised of Phomopsis, Alternaria, and Aspergillus, representing 76.10% of the total. Phomopsis and Colletotrichum appeared in each season, with Phomopsis as the dominant genus, accounting for 89.65%, 43.51%, 35.51%, and 75.35%, respectively in spring, summer, autumn and winter. Epiphytic fungi were mainly composed of Penicillium, Phoma, and Phomopsis, comprising 55.05% of the total, with Alternaria, Phomopsis, and Colletotrichum appearing each season. In spring, the diversity, richness, and evenness of endophytic fungi were lower than those of epiphytic fungi, whereas in summer and autumn, the opposite was true; in winter, endophytic fungi had lower diversity and evenness but higher richness. The similarityindex between the two communities was high (C_s=0.76), with no significant difference (P>0.05).

Conclusion The endophytic and epiphytic fungal communities in P. tatarinowii are diverse and highly similar, exhibiting seasonal differences. Seasonal changes cause shifts in the internal and external ecological factors of P. tatarinowii, driving corresponding changes in community diversity.