Dynamic Characteristics of Rhizosphere Bacteria Communities During Different Growth Stages of Strawberry

Abstract

The rhizosphere, directly influenced by root systems of plant, plays a significant role in plant-microbe interactions, which in turn directly affect the plants. In this work, the dynamic characteristics of rhizosphere bacterial communities during the growth period of cultivated strawberry (Fragaria×ananassa ‘Hongyan’) were investigated, and the dominant bacterial species in different growth stages were identified. High-throughput sequencing (HTS) was employed to obtain operational taxonomic unit (OTU) abundance, bacterial community diversity, and abundance of rhizosphere bacteria at five growth stages of strawberry: growth period (A1.1), budding period (A2.2), flowering period (AB3.2), fruiting period (AB4.1) and mature fruit period (AB5.2). The composition and abundance of bacterial communities structure were analyzed using the unweighted pair group method with arithmetic means (UPGMA) cluster analysis. The result indicated that, in the flowering stage the bacterial community exhibited the highest diversity and richness, while the bud stage had the least. The flowering stage showed a greater specific bacteria species in the strawberry rhizosphere, followed by growth, mature and harvest stages, and the lowest in the bud stage. The main dominant phyla were Actinobacteria, Proteobacteria and Acidobacteria, accounting for over 70% of the total bacterial abundance. The main dominant genera were Alcanivorax, Kaistobacter, Marinobacter and Candidatus Nitrososphaera. The bacterial abundance similarity was relatively high in the growth and harvest stages, as well as in flowering and mature stages, while it differed greatly from that of the bud stage. In conclusion, the difference in bacterial diversity between bud stage and flowering stage was the greatest, with the Chao1 index and Shannon index increased by 79.35 and 6.74%, respectively. The rhizosphere bacterial community richness and diversity were highest at the flowering stage (AB3.2), with 198 specific OTUs accounting for 7.48% of the total OTUs. At the phylum level, the bacterial abundance of Proteobacteria, Acidobacteria and Actinobacteria were greatly affected by the developmental stage. These findings suggest that the bacterial diversity of strawberry rhizosphere will change with the growth stage.