内蒙古中部地区马铃薯根际和根系丛枝菌根真菌类群的多样性

Arbuscular mycorrhizal fungi population diversity of rhizosphere soil and root system in potato field in central Inner Mongolia

摘要:

【背景】丛枝菌根真菌(arbuscular mycorrhizal fungus，AMF)是菌根真菌中分布最广泛的一类真菌，能够与90%以上的植物形成菌根共生体，并通过调节宿主体内的代谢活动增强植物的抗逆性。【目的】揭示内蒙古马铃薯主产区土壤中AMF的结构与组成，解析马铃薯不同发育阶段以及连作对AMF类群的影响。【方法】以内蒙古中部地区大井村、徐麻夭村和红格尔图村采集的马铃薯根系及根际土为材料，通过PCR扩增建立18s rRNA基因文库，研究不同地点、不同马铃薯生育阶段以及连作对马铃薯根系内和根际土中的AMF类群组成和多样性的影响。【结果】大井村和红格尔图村马铃薯根际土中的AMF的类群多样性优于徐麻夭村，其中Glomus为大井村和红格尔图村马铃薯根际土样本中AMF的优势菌群，而徐麻夭村样本根际土中的优势类群为Diversispora。马铃薯根系中的AMF多样性的研究结果表明，3个供试地点根系内AMF类群的类型没有显著差异，但是AMF类群的比例却不同。大井村根系样本中AMF的优势菌为Diversispora，而Rhizophagus是红格尔图村和徐麻夭村根系样本中的优势AMF类群。同一供试地点马铃薯苗期和块茎膨大期根际土中的AMF类群的类型多于块茎形成期，其中Glomus是马铃薯不同发育阶段根际土中的优势类群；而Rhizophagus是3个不同发育阶段根系内的优势类群。2015和2016年马铃薯连作地块中根际土和根系内AMF类群的类型完全相同，但是不同的AMF类群的相对丰度随着马铃薯的连作呈现出显著的变化。其中，根际土样本中Glomus和Archaeospora类群的相对丰度随着连作有所上升，相应的Entrophospora和Diversispora相对丰度有所下降；根系样本中AMF的优势类群随着连作从Glomus转变为Rhizophagus。AMF多样性测定结果表明，连作对马铃薯根际土中AMF多样性的影响显著高于对根系内类群的影响。【结论】AMF类群的多样性会因土壤组成成分、马铃薯生育期和连作效应而呈现不同变化。

Abstract:

[Background] Arbuscular mycorrhizal fungus (AMF) is the most widely distributed fungi in mycorrhizal fungi. They can form mycorrhizal symbiosis with more than 90% of the plants, and enhance the resistance of plants by regulating metabolic activities in the host. [Objective] To reveal the structure and composition of AMF in soil of main potato producing areas in Inner Mongolia, and analyze the effects of different development stages of potato and continuous cropping on AMF groups. [Methods] Using root and rhizosphere soils of potato collected from Dajing, Xumayao and Honggeertu villages in central of Inner Mongolia as material, though PCR amplification and establishing 18S rRNA gene library, try to study the effect on AMF composition and diversity in potato rhizosphere soils and root at different locations, different growth stage and continuous croping plot. [Results] AMF diversity of rhizosphere soil in Dajing village and Honggeertu village was more than that in Xumayao village, the dominant strain was Glomus in both Dajing village and Honggeertu village, while Diversispora was the dominant strain in Xumakuo village. In roots, the results of AMF diversity showed that there was no significant difference among three areas, but the proportion of AMF population was different. Diversispora was the dominant strain in Dajing village, Rhizophagus was the dominant strain in Honggeertu village and Xumayao village. The AMF diversity of potato rhizosphere soil in seedling stage and tuber swelling stage were more than that in tuber formation stage at the same area, Glomus was the dominant strain in the three stages, while in root the Rhizophagus was the dominant strain in the three stages. After 2015 and 2016 continuous cropping potato in Dajing village, the types of AMF populations in rhizosphere soil and root were identical, but the relative abundance of different AMF populations changed significantly. Among the rhizosphere soil samples, the relative abundance of Glomus and Archaeospora population increased with continuous cropping, and the relative abundance of Entrophospora and Diversispora decreased. But the dominant population of AMF in root samples changed from Glomus to Rhizophagus with continuous cropping. This result indicated that the effect of continuous cropping on AMF diversity in rhizosphere soil was significantly higher than that in root. [Conclusion] The diversity of AMF population varies with soil composition, potato growth period and cropping effect.