Effects of feeding stress of Phthorimaea operculella potato rhizosphere bacteria community structure and diversity

【Objective】To explore the effects of Phthorimaea operculella(Zeller) feeding stress on the community structure and diversity of potato rhizosphere bacteria, and to systematically analyze the interaction effect of “plant-pestrhizosphere microorganisms”, so as to provide a reference for the screening and utilization of potato rhizosphere beneficial microorganisms. 【Method】In the laboratory, the composition and diversity of rhizosphere bacteria in four growth stages, including potato seedling stage, tuber formation stage, starch accumulation stage and maturity stage, were analyzed using potted potato variety Cooperation 88 as experimental materials. At the same time, the 3^rd instar larvae of P. operculella were inoculated at the elongation of the 5^th lateral branch at the potato seedling stage, non-inoculation was as control,and the rhizosphere soil in treatment and control was collected at 12, 24, 36 and 48 h, respectively, and the αdiversity analysis and principal component analysis were carried out by Mothur on the potato rhizosphere bacterial communities at four growth stages, and different feeding stress times and control at seedling stage. Using MEGA 7.0 based on the similarity of bacterial 16S rRNA sequences, the top 20 strains in abundance were compared with each other, and phylogenetic evolutionary trees were constructed,functional prediction of rhizosphere bacteria 16S rRNA was conducted by PICRUSt1. 【Result】The ACE and Chao1 indexes of rhizosphere bacterial species at potato maturity stage were significantly higher(P<0.05, the same below) than those at the other three stages. After the feeding stress of P. operculella, the main dominant bacteria in the potato rhizosphere bacterial community were in the order of Actinomycetes>Proteobacteria>Chloromyticus>Acidobacteria>Firmicutes, the relative abundance of Actinomycetes increased by 7.91%, 26.54%, 21.56% and 2.97% at 12, 24, 36 and 48 h, respectively, and feeding stress increased the relative abundance of Proteobacteria and Bacteroidetes, decreased the relative abundance of Acidobacter. At the genus level, the relative abundance of Arthrobacter spp. increased by 137.39%, 113.58%, 93.12% and 61.87% compared with CK at 12, 24, 36 and 48 h after feeding stress, respectively, feeding stress increased the relative abundance of Sphingomonas spp., and decreased the relative abundance of norank_ f_ norank_ 0_ Vicinamibacterales and norank_ f_ Vicinamibacteraceae. The results of principal component analysis showed that potato rhizosphere bacteria of the control group and the treatment group were greatly separated. The phylogenetic tree results showed that the top 20 strains in relative abundance belonged to Actinomycetes, Crucidomycetes, Firmicutes, Acidobacteria and Blastomonas. There were 24 functional categories of COG annotation, among which amino acid transport and metabolism were the most enriched. 【Conclusions】The community structure and relative abundance of potato rhizosphere bacteria change due to feeding stress of P. operculella, among which the relative abundance of Arthrobacter spp. of Actinomycetes changes the most significantly.