Abstract:

Aim: Phyllosphere micro-organisms are crucial to plant growth and development, but little is known about the diversity and community structure of phylloshphere fungi in Helianthemum songaricum.

Methods: In this study, Illumina high-throughput sequencing techniques were used to detect the diversity of phyllosphere epiphytic and endophytic fungi in H. songaricum collected from Qipanjing, Lasengmiao, and Qianlishan in the West Ordos Nature Reserve. In addition, we investigated the characteristics of their network structure and the mechanisms of their community assembly.

Results: For H. songaricum sampled from Qipanjing, the phyllosphere epiphytic fungal richness index (156.38 ± 8.42) was significantly higher than that of endophytic fungi (111.13 ± 5.57). Besides, the phyllosphere epiphytic fungal richness index of H. songaricum sampled from Qipanjing was significantly higher than that of those sampled from Lasengmiao (125.57 ± 7.20) and Qianlishan (114.75 ± 10.35). On the contrary, the endophytic fungal richness index of H. songaricum sampled from Lasengmiao (155.71 ± 15.40) was significantly higher than those sampled from Qipanjing. Phyllosphere fungi were dominated by Ascomycota, Mucormycota, and Basidiomycota, with significant indicator taxa for phyllosphere epiphytic and endophytic fungi at the three sampling locations, suggesting that the leaf position (leaf surface and leaf interior) and sampling site significantly influenced the community composition of phyllosphere fungi. Co-occurrence network analysis showed that the phyllosphere epiphytic and endophytic fungi were mainly synergistic, with limited antagonistic effects. In addition, the assembly of phyllosphere epiphytic and endophytic fungal communities in H. songaricum was mainly driven by stochastic processes.

Conclusion: The diversity and community composition of phyllosphere epiphytic and endophytic fungi of H. songaricum are significantly influenced by leaf position (leaf surface and leaf interior) and sampling site, with stochastic processes dominating the community assembly of phyllosphere epiphytic and endophytic fungi. This research provides valuable scientific insight and practical guidance for the conservation and rational utilization of H. songaricum.

Key words: Helianthemum songaricum, phyllosphere fungi, ecological process mechanisms, co-network