Variation in the mulberry rhizosphere microenvironment and leaf quality with habitat and variety

Abstract

The rhizosphere is a hotspot for plant-soil microorganism interactions. There are limited reports describing the differences in bacterial communities of the mulberry rhizosphere soil among different regions. The present study conducted high-throughput sequencing on the bacterial diversity of the mulberry rhizosphere soil based on 16S rRNA amplicon sequencing via the Illumina MiSeq PE300 platform, aiming to explore the relationship between bacteria, rhizosphere microenvironment, and leaf quality. We examined two mulberry varieties, ‘Husang 32’ (H32) and ‘Xuan 792’ (X792), sampled from five locations in Shandong, China. Significant differences were found in rhizosphere bacteria, soil chemical properties, and leaf nutrients among regions as well as between varieties. The effect of variety on bacterial richness and diversity was region-dependent. In Jvxian, both richness and diversity were significantly higher in X792 than in H32, whereas the opposite pattern was observed in Taian, where Actinobacteriota and Proteobacteria were the dominant phyla of both X792 and H32. Soil chemical properties showed the strongest explanatory power for the differences in mulberry rhizosphere bacteria (26.60%), followed by leaf nutrients (19.61%) and climate (3.02%). Na, Ca, and electrical conductivity (EC), along with foliar Ca, lignin, and cellulose, exhibited the largest correlation coefficients with rhizosphere bacterial communities. Our findings confirmed that the interaction between region and variety had a greater impact on bacterial communities, soil chemical properties, and leaf quality than either region or mulberry variety alone, and that region had a greater effect than variety. Furthermore, beneficial genera Bacillus , Nitrospira, and Rubrobacter are vital for optimizing the mulberry rhizosphere microenvironment and improving leaf quality. This study offers theoretical evidence to elevate mulberry leaf quality by manipulating microbial biofertilizers