The response of sugar beet rhizosphere micro-ecological environment to continuous cropping

Abstract

Continuous cropping can lead to increased soil-borne diseases of sugar beet (Beta vulgaris L.), resulting in a reduction in its yield quality. However, our understanding of the influence of continuous cropping on sugar beet-associated microbial community is limited and their interactions remain unclear. Here, we described and analyzed microbial diversity (N = 30) from three sugar beet belowground compartments (bulk soil, rhizosphere soil, and beetroot) using 16S rRNA and ITS sequencing. The continuous cropping showed lower bacterial alpha diversity in three belowground compartments and higher fungal alpha diversity in roots compared to the non-continuous cropping. There were significant differences in fungal community composition between the two groups. Compared with non-continuous cropping, continuous cropping increased the relative abundance of potentially pathogenic fungi such as Tausonia, Gilbellulopsis, and Fusarium, but decreased the relative abundance of Olpidium. The fungal flora in the three compartments displayed different keystone taxa. Fungi were more closely related to environmental factors than bacteria. Overall, changes in microbial diversity and composition under continuous cropping were more pronounced in the fungal communities, and the results of the study could guide development strategies to mitigate continuous crop adversity.

The succession of rhizosphere microbial community in the continuous cropping soil of tobacco

“…As reported, Mortierella could dissolve mineral phosphorus in soil by synthesizing and secreting oxalic acid (Spaepen et al, 2007), and it can also grow rapidly in iron-rich soil and use its mycelium to facilitate the growth of beneficial bacteria such as Bacillus (Jeewani et al, 2021). Olpidiomycota has also been reported to be significantly enriched in non-continuous cropping sugar beets (Cui et al, 2022). However, an opposite result was shown, where the abundance of Chytridiomycota increased significantly in the continuous cropping of sweet potato (Gao et al, 2019).…”

Understanding the sugar beet holobiont for sustainable agriculture

“…Protists play a pivotal role in shaping sugar beet rhizosphere microbiomes (Bazany et al, 2022), but are rarely investigated on metagenomic levels. Interestingly, sugar beet rhizospheres were repeatedly reported to display a comparable (Mendes et al, 2011), or even higher bacterial alpha diversity than surrounding bulk soil in the early seedling stages (Zachow et al, 2014;Wolfgang et al, 2020), but also in the rhizosphere of preharvest taproots (Cardinale et al, 2020), while also significant lower rhizosphere alpha diversity compared to bulk soil was reported (Cui et al, 2022). Rhizosphere communities in vascular plants are usually less diverse than soil communities (Berendsen et al, 2012).…”

“…. composition (Huang et al, 2020;Pervaiz et al, 2020;Cui et al, 2022). Effects in sugar beet include potassium depletion in soil (Samadi, 2012), rapid crop yield loss mainly due to plant disease intensification (Stevanato et al, 2019), and accumulation of potentially autotoxic root exudates (Huang et al, 2021).…”

“…As the physical, chemical, and biological activity of a plant itself shapes its surroundings even past its lifespan, continuous cropping of sugar beet severely affects soil traits. Continuous cropping usually leads to detrimental effects on yield and soil properties due to an imbalance in soil nutrients, autotoxicity of root exudates, and shifts in microbial community composition (Huang et al, 2020 ; Pervaiz et al, 2020 ; Cui et al, 2022 ). Effects in sugar beet include potassium depletion in soil (Samadi, 2012 ), rapid crop yield loss mainly due to plant disease intensification (Stevanato et al, 2019 ), and accumulation of potentially autotoxic root exudates (Huang et al, 2021 ).…”

“…The genera Sphingomonas, Haliangium, Gaiella , and Lysobacter were positively correlated, while Lysinibacillus and Sphingobacterium negatively correlated with sugar beet cropping time (Huang et al, 2020 ; Du et al, 2022a , b ). It appears that long-time rotation with other crops does not fully restore the negative effects on sugar beet biomass, health parameters, and yield as well as on the community shift in bacterial (Cui et al, 2022 ; Du et al, 2022a ) and fungal (Cui et al, 2022 ; Du et al, 2022b ) rhizosphere microbiome compared to sugar beets grown in virgin soil. Strategies to re-establish the microbiome-related beneficial effects on plant growth found in virgin soil, while increasing the sustainability of the crop is a challenge of future sugar beet research.…”