Abstract:

This study revealed the changes of bacterial community structure and diversity in facility cucumber rhizosphere soil affected by different reactors,aiming at providing theoretical basis and practical basis for cucumber rhizosphere soil improvement and sustainable utilization of protected soil.This experiment was based on the V3-V4 region of the 16S rRNA gene,seven treatments namely,original greenhouse soil(CK),untreated cucumber rhizosphere soil for 100 days(CK1) and 200 days(CK2),corn straw bioreactor-treated cucumber rhizosphere soil for 100 days(S1)and 200 days (S2),and sheep manure bioreactor-treated cucumber rhizosphere soil for 100 days(M1)and 200 days(M2).High-throughput sequencing technology using Illumina Miseq was used to analyze the diversity,structure,and physical and chemical properties of the bacterial communities in the rhizosphere soils of different bioreactor treatments on facility cucumber.The results showed that 6 344 OTUs were obtained from soil samples after sequencing,which mainly belonged to 39 phyla,315 orders and 980 genera.M2 treatment could improve the bacterial richness in cucumber rhizosphere soil and significantly increase the diversity of bacterial community.At the phylum level,the dominant population structure of bacterial phylum in soil treated by corn straw bioreactor and sheep manure bioreactor was similar,among which Actinobacteriota and Proteobacteria were the dominant phylum.At the genus level,norank_f_JG30-KF-CM,Arthrobacter,norank_f_norank_o_Gaiellales,norank_f_67-14,Blastococcus,Gaiella and Marmoricola were significantly different among different treatments.According to the composition of bacterial community abundance,M2 and S2 treatments increased the relative abundance of some beneficial bacterial groups in cucumber rhizosphere to some extent.RDA analysis showed that the soil bacterial community was significantly affected by soil environmental factors,and the contents of ammonium nitrogen(P=0.015),total potassium(P=0.002)and available potassium(P=0.005)had significant effects on the bacterial community.Therefore,M2 treatment can improve the bacterial richness in facility cucumber rhizosphere soil,increase the diversity of bacterial community and change the bacterial community structure,which is beneficial to the improvement of facility cucumber rhizosphere soil.

Key words: Facility cucumber, Rhizosphere soil, Bioreactor, Bacterial community, High-throughput sequencing