宁夏贺兰山青海云杉根系共生真菌的分离与鉴定

Isolation and identification of symbiotic fungi in roots of Picea crassifolia on Helan Mountain in Ningxia, China

摘要:

【背景】青海云杉(Picea crassifolia)是中国特有植物，具有极高的生态价值，是西北地区重要的森林更新树种和荒山造林树种，其生长发育及其抗逆性与根系共生真菌多样性密切相关。【目的】从青海云杉根系分离并鉴定定殖的可培养共生真菌，阐明青海云杉根系可培养共生真菌的种类组成，为共生真菌在青海云杉育苗、造林及生态恢复的应用研究提供依据。【方法】采用根段直接分离培养法，对青海云杉根系共生真菌进行分离培养，描述菌落形态特征。结合rDNA ITS序列分析的方法，对分离的真菌进行鉴定。【结果】从青海云杉根系中分离获得65株真菌，隶属 1门4纲8目13科16属18种，均属于子囊菌门(Ascomycota)；属水平上，以瓶头霉属(Phialocephala)分离频率最高，占分离菌株总数的31%；种水平上，以Phialocephala lagerbergi分离频率最高(22%)，Cadophora interclivum、Pleotrichocladium opacum、福廷瓶头霉(Phialocephala fortinii)和Alfoldi sp.次之，分别为18%、17%、9%和9%。从不同发育阶段的青海云杉根系分离得到的共生真菌的种类和数量不同，其中幼树阶段分离频率最高(52%)，幼苗阶段次之(28%)，成树阶段最低(20%)。【结论】宁夏贺兰山青海云杉根系可培养的共生真菌种类丰富，其种类和数量在植株不同发育阶段差异较大。本实验分离的真菌种类均为青海云杉中首次获得。本研究结果是以往相关研究的重要补充，为进一步挖掘青海云杉根系共生真菌资源、探索青海云杉适应本地高寒与干旱逆境的共生微生物组作用机制奠定了基础。

Abstract:

[Background] Picea crassifolia, an endemic plant with great ecological value in China, is an important tree species for forest regeneration and afforestation in desert mountain areas in Northwest China. The diverse symbiotic fungi in the roots of P. crassifolia contribute to its growth, development, and stress resistance. [Objective] The culturable symbiotic fungi were isolated from the roots of P. crassifolia on Helan Mountain and identified to reveal the fungal community composition. The results provide basic data for seedling breeding, afforestation, and ecosystem restoration of P. crassifolia. [Methods] The culturable symbiotic fungi in the roots of P. crassifolia were isolated directly from root tips and identified based on the morphological characteristics of colony and the rDNA ITS sequence. [Results] A total of 65 fungal strains were isolated from the roots of P. crassifolia, belonging to 18 species, 16 genera, 13 families, 8 orders, 4 classes of 1 phylum (Ascomycota). Phialocephala was the genus with the highest isolation frequency, with the isolates accounting for 31% of the total isolates. Phialocephala lagerbergi was the species with the highest isolation frequency (22%), followed by Cadophora interclivum (18%), Pleotrichocladium opacum (17%), Phialocephala fortinii (9%) and Alfoldi sp. (9%). The species and number of the symbiotic fungi varied at different development stages of P. crassifolia. The fungal isolation frequency in the roots of saplings, seedlings, and adult trees was 52%, 28%, and 20%, respectively. [Conclusion] The symbiotic fungi in the roots of P. crassifolia on Helan Mountain in Ningxia were diverse, the species and number of which varied at different development stages of the tree. All the isolated fungi in this study were obtained from P. crassifolia for the first time. The results are an important supplement to previous related studies, laying a foundation for further investigating the resources of culturable symbiotic fungi in the roots of P. crassifolia and exploring the role of symbiotic fungi in the process of P. crassifolia adapting to the alpine and arid environment.