杉木人工林土壤真菌遗传多样性

为探明杉木人工林土壤真菌遗传多样性及其与环境因子的关系,采用454测序技术对土壤真菌的遗传多样性进行了分析,测定了黄丰桥林场杉木人工林土壤真菌的遗传多样性与环境因子的相关性。试验结果表明:①不同代数、林龄的杉木人工林土壤理化性质及林下植被多样性均有显著差异。第1代杉木幼林林土壤肥力较高,有机质、全N、速效K的均值分别为88.02g/kg、2.56 g/kg、84.96 mg/kg均高于第2代和第3代杉木幼林林,速效N和含水量的均值分别为22.86 mg/kg和26.28%低于其他样地。杉木幼林林下植被多样性最为丰富。②通过454测序技术分析发现第1代杉木幼林真菌Ace丰富度指数、Chao丰富度指数及群落遗传多样性指数均大于第2代杉木幼林和第3代杉木幼林。杉木人工林土壤中粪壳菌纲(Sordariomycetes)真菌为优势种群。不同栽培代数杉木人工林的真菌群落存在差异,其中块菌科(Tuberaceae)为第2代和第3代杉木林特有真菌,而不同发育阶段的杉木人工林的真菌群落差异不明显。③经RDA分析,杉木人工林土壤主要真菌群落受含水量、有机质、速效P、速效K影响较大。土壤真菌群落遗传多样性Shannon-Wiener多样性指数与林下植被多样性、土壤全N显著正相关,土壤真菌Chao指数与土壤真菌Shannon-Wiener多样性指数、土壤全N含量显著正相关。本研究表明不同栽培代数杉木人工林的真菌群落存在差异,土壤真菌群落与环境因子之间具有相关性。

Fungal diversity in Cunninghamia lanceolata plantation soil

Cunninghamia lanceolata(Lamb.)Hook. (Chinese fir) is one of the most important industrial timber species in China, the area of Chinese fir plantation accounts for 21.35% of the total plantation area in China. At present, the Chinese fir plantation has some problems such as continuous planting, single tree species, mismatch tree species with site and so on, this contributed to productivity decline and soil degradation. Remarkable changes caused by soil degradation, for instance, soil microorganism, soil physic-chemistry characteristics, soil enzyme activity and undergrowth vegetation, etc.Soils represent a huge reservoir of biodiversity with several billion prokaryotic and eukaryotic microorganisms, corresponding to numerous different taxa, inhabiting a single gram of soil. Fungi are the dominant eukaryotic lineage in terms of biomass in soil, where they play key roles as decomposers, pathogens, and mycorrhizal mutualists. Due to their large number of species, specialization, and important ecological functions, fungi are also excellent bioindicators. Investigating the fungal diversity becomes crucial for the ecological characterization of any given site.Traditionally, diversity was assessed using selective plating and direct viable counts. Limitations include uncultivable microorganisms not detected, bias towards fast growing individuals, and bias towards fungal species that produce large quantities of spores. High-throughput tag-encoded FLX amplicon pyrosequencing has been used to study fungal diversity and allows identification of fungal as well as the prediction of phylogenetic relationships. This method avoided the limitations of plate count.This study aims to provide an overview of soil fungal diversity in soils of Chinese fir plantations and examine the relationship between soil fungal diversity and environmental factors. To achieve the objectives, we employed high-throughput tag-encoded FLX amplicon pyrosequencing to analyze fifteen soil samples from the Chinese fir plantation forests at the Huangfengqiao farm. Our analyses showed that there were significant differences in soil physical-chemical characteristics and undergrowth vegetation among the sites that differed in forest age. Specifically, the soil from the first generation Chinese fir plantation had higher organic matter, total N, and available K than those from the second generation and the third generation Chinese fir soils. Similarly, the 454 pyrosequencing results showed that the fungal Ace index, Chao index and fungal genetic diversity of the first generation young Chinese fir soil were all higher than those in the soils from the second generation and the third generation Chinese fir plantations. The dominant phylogentic group was Sordariomycetes. Interestingly, fungi in family Tuberaceae were found only in soils of the second and third generation Chinese fir plantations. The RDA analyses identified that moisture content, organic matter, available P, and available K in the Chinese fir plantation forest all contributed to differences in the distributions of dominant soil fungi. The diversity of soil fungi was positively correlated with undergrowth vegetation diversity and total N. Similarly, the Chao index was correlated with Shannon-Weaver index and total N. In conclusion, our analysis of fungal 18S rRNA-based datasets revealed differences in soil fungal community structure among the different plantations of the Chinese fir and that the differences were correlated with the soil physical-chemical characteristics as well as undergrowth vegetations. Further research is needed to understand the detailed mechanisms responsible for the observed differences.