Abstract:

Objective: This paper aims to study the diversity of the fungus community structure in heartwood and sapwood of Dalbergia odorifera, and their relationship with the internal environmental factors, in order to provide a basis for the evaluation of endophytic fungi and resource utilization in the trunk of D. odorifera, and further to provide a theoretical basis for artificially promoting the formation of heartwood of D. odorifera. Method: High-throughput sequencing technology was used to study the community structure and diversity of endophytic fungi in the heartwood and sapwood, and the relationship with the physical and chemical properties of heartwood and sapwood was analyzed by means of variance analysis and redundancy analysis. Result: A total of 2 193 336 sequences were obtained with high-throughput sequencing. The total number of bases was 761 438 850 bp, and the effective sequence had an average length of 385 bp. There were 3 621 OTUs, belonging to 26 classes, 67 orders, 116 families, 167 genera and 186 species. At the class level, the dominant flora of endophytic fungi of heartwood was:Agaricomycetes, Sordariomycetes and Eurotiomycetes; the dominant flora of endophytic fungi of sapwood was:Sordariomycetes, Dothideomycetes, Agaricomycetes, Geoglossomycetes and Tremellomycetes. At the genus level, the dominant fungi of endophytic fungi in heartwood were:Phaeoacremonium, Fusarium, Sporothrix, Cladophialophora and Gongronella; the dominant endophytic fungi insapwood were:Fusarium, Lasiodiplodia, Cladosporium, Candida, Debaryomyces and Trichoderma. At the species level, the dominant flora of endophytic fungi of heartwood was:Sporothrix lignivora, Gongronella butleri and Fusarium oxysporum; the dominant flora of endophytic fungi of sapwood was:Lasiodiplodia theobromae, yeast Debaryomyces udenii and Fusarium pseudensiforme. The results of redundancy analysis showed that pH, ash and potassium were negatively correlated with the community structure of endophytic fungi, and hot water extract, magnesium and calcium were positively correlated with most fungal communities, and negatively correlated with a small number of fungal communities. Water content, hot water extract, mineral element calcium and magnesium were positively correlated with the diversity index, such as chaol, shannon and simpson, while pH, ash and potassium were negatively correlated with them. Conclusion: Endophytic fungal population is rich in heartwood and sapwood of D. odorifera.The richness and diversity of endophytic fungi community in the heartwood arelarger than that in the sapwood. The structural differences in endophytic fungal populations in heartwood and sapwood are mainly affected by wood environmental factors, such as pH, ash and mineral element potassium. The diversity of endophytic fungi populations in heartwood and sapwood is mainly affected by environmental factors in wood, such as pH, water content, mineral elements calcium and potassium.

Key words: Dalbergia odorifera, heartwood, sapwood, high-throughput technology, endophytic fungi, community structure, diversity