海南岛不同林龄短枝木麻黄凋落物内外真菌多样性分析

Abstract

以海南海口桂林洋滨海立地上幼龄林、中龄林和成熟林短枝木麻黄为研究对象，采集凋落物和林地土壤样品，利用IlluminaMiseq PE300测序平台对凋落物内外真菌ITS rDNA进行高通量测序，分析了凋落物内外真菌群落多样性及其与凋落物和林地土壤理化性质的关系。结果表明：（1）所有样品获得669476条有效序列，隶属6门23纲59目119科212属314种。3林龄木麻黄凋落物外生真菌多样性和丰富度高于内生真菌。（2）内外真菌群落结构有较大共性，子囊菌门和担子菌门为优势门，煤炱目、炭角菌目和木耳目为内外真菌共同优势目。Coniochaetales、Magnaporthales等4个目仅在凋落物内部分布，而蛙粪霉目、丝孢酵母目为外生真菌特有菌群。（3）木麻黄凋落物pH值和有机碳显著影响着凋落物内生真菌群落结构，而土壤容重和铵态氮显著影响着外生真菌群落结构。研究结果为探讨微生物在木麻黄凋落物降解过程中作用的研究奠定基础。;Casuarina equisetifolia forests are widely spread in tropical to subtropical coast, serving as windbreak forests. However, C. equisetifolia forests have poor natural regeneration rate, which were considered involving the allelopathy of the litter. The aim of the study was to investigate the characteristics of endophytic and epiphytic fungal communities of the litter in C. equisetifolia forests (young-aged forest, middle-aged forest and mature-aged forest) at Guilinyang coast of Haikou, Hainan province, China. The ITS rDNA was sequenced by Illumina high-throughput sequencing technology, which was used to analyze the diversity of the microbial communities of the litter from different aged forests. The litter and soil physicochemical properties were measured to determine the correlations between them. A total of 669,476 valid sequences were obtained for all samples and contained 6 phyla, 23 classes, 59 orders, 119 families, 212 genus, and 314 species. The diversity and abundance of the epiphytic fungal communities of the C. equisetifolia litter was higher than those of the endophytic fungi. There were greater similarity among the endophytic and epiphytic fungal community compositions. It was found that Ascomycota and Basidiomycota were the main fungi of the litter. There were three dominant orders exist in both endophytic and epiphytic fungal communities, including Capnodiales, Xylariales and Auriculariales. Coniochaetales, Magnaporthales and another two orders were specially distributed in the litter, while Basidiobolales and Trichosporonales were endemic to epiphytic fungi. The pH and organic carbon of the litter were significantly correlated to endophytic fungal community structure, while the bulk density and ammonium nitrogen of the soil were significantly correlated to epiphytic fungal community structure. This work provided an important theoretical basis for studying the role of microorganisms in the decomposition of C. equisetifolia litter.