Evaluation the effects of fungicide Iprodione-Carbendazim (Rovral TS) on cucumber rhizosphere bacterial structure by Illumina MiSeq sequencing

Studying the effects of fungicides on rhizosphere and soil microbial communities is very important due to the critical role of microorganisms in soil and plant health. In this study, the effects of fungicide Rovral TS on dynamic and structure of cucumber rhizospheric bacteria was investigated by Next-Generation Sequencing based on 16S rRNA gene (V4 region) by means of Illumina MiSeq sequencing in three plant growth periods. Results showed that among 26 identified phyla and 352 identified bacterial genera for 18 samples, Proteobacteria and Pseudomonas were most dominate phylum and genus, respectively. Application of Rovral TS was resulted the changes in bacterial structure and dynamic. Decrease of relative abundance of Pseudomonas in middle stage of flowering in fungicide treatment and in the last stage of control treatment was observed. Moreover, the relative abundance of Sphingopyxis, Sphingobacterium and Chryseobacterim in fungicide-treated plants were more than control plant in all three stages. Analysis of diversity indices revealed that diversity in the rhizospheric soil of control plant was more than fungicide-treated plants (shanon=5.33), while species richness in control soil was greater than fungicide treated (Chao1=2324.17). In addition, the effect of plant developing stages on OUT number, diversity and richness indices (regardless type of treatment) was significant and rhizospheric soil belongs to before flowering stages benefit more diversity and richness.