半夏连作对根际土壤微生物群落的影响研究

Effects of continuous cropping of Pinellia ternata on rhizospheric microbial community

目的探明半夏Pinellia ternate连作对根际土壤微生物群落的影响规律,以指导半夏连续高产栽培。方法采用PacBio Sequel测序手段对正茬(CK)、连作一茬(A)、二茬(B)和三茬(C)半夏不同生长时期根际土壤微生物进行测序,对比分析其微生物群落结构和多样性差异。结果随着连茬次数的增加,潜在致病细菌如果胶杆菌Pectobacterium aroidearum、真菌如子囊菌门Ascomycota菌群、镰刀菌属真菌Fusarium nematophilum和瓜亡革菌Thanatephorus cucumeris等丰度增加,球黑孢霉Nigrospora_zimmermanii随着连茬次数的增加逐渐成为优势菌群,有益真菌如球囊菌门Glomeromycota菌群丰度减少;随着连茬次数增加,半夏根际土壤中细菌和真菌多样性均降低;根际土壤pH值随着半夏生长周期的延长波动变化,可能导致根际细菌和真菌多样性和功能类群变化,从而使一些致病菌在半夏块茎膨大期和成熟期形成优势种群。结论随着半夏连茬次数的增加,根际土壤有益微生物丰度减少、有害微生物丰度增加,根际土壤微生物群落多样性降低,根际土壤pH值波动变化,是半夏连作障碍形成的重要原因。

Objective Response of continuous cropping of Pinellia ternata to rhizospheric microbial community is of great significance for realizing the industrialized cultivation of P.ternata.Methods PacBio Sequel platform was used to conduct sequencing studies on the differences of rhizospheric microbial community and diversity of P.ternata at different growth stages under the different treatments of the first cropping(CK),the first continuous cropping(A),the second continuous cropping(B),and the third continuous cropping(C).Results(1)As the number of continuous cropping of P.ternata increases,the abundance of potential pathogenic bacteria and fungi increased,such as Pectobacterium_aroidearum,Ascomycota,Fusarium_nematophilum and Thanatephorus_cucumeris etc.Nigrospora_zimmermanii gradually became the dominant flora as the number of consecutive stubbles increased the abundance of beneficial fungi such as Glomeromycota decreased.(2)As the number of continuous cropping of P.ternata increases,the diversity of bacteria and fungi in the rhizosphere soil of P.ternata decreased.(3)The different growth periods of P.ternata have obvious effects on the pH of the rhizosphere soil,which leads to changes in the diversity and functional groups of rhizosphere bacteria and fungi.Some pathogenic fungi such as N._zimmermanii became dominant groups during the tuber expansion and maturity stages of P ternata.Conclusion The change in the structure and biodiversity of rhizospheric microbial community caused by the increase in the number of continuous cropping of P.ternata,the decrease of beneficial microbe abundance,the increase of harmful microbe abundance,and the decrease of microbial community biodiversity are important reasons for the continuous cropping obstacles of P.ternata.