Enrichment of phytopathogen dominated by Volutella in the rhizosphere
may be an important cause of continuous cropping obstacles in
sweetpotato
Abstract
Obstacles related to the continuous cropping of sweetpotato (
Ipomoea batatas (L.) Lam.) restrict its intensive production.
However, the effects of continuous cropping on soil properties and/or
the rhizosphere microbial community are largely unclear. In this study,
we analysed changes in rhizosphere soil chemical properties and
microbial communities of sweetpotato across different cultivation years.
We observed that the microbial diversity and complexity of the fungal
ecological network in rhizosphere soils of sweetpotato were decreased
after 5 years of continuous cropping, with significant enrichment in
Sphingobium, Gemmatimonas, Volutella, and
Neoidriella. Tuber yield, soil pH, and available potassium (AK)
content were significantly reduced after continuous cropping, with the
soil microbial community having the highest correlation with pH, AK, and
ammonium nitrogen (NH 4 +-N).
Specifically, soil pH and AK were positively correlated with
Bacillus and Gaiella, and negatively correlated with some
plant-pathogenic fungi ( Volutella and Neoidriella), while
NH 4 +-N showed the opposite trend. In
addition, soil pH, AK, and the relative abundance of Bacillus
were positively correlated with tuber yield, while Volutella
showed the opposite trend. In summary, the continuous cropping of
sweetpotato negatively affects rhizosphere soil health, resulting in
imbalanced soil fertility and increased abundance of pathogens. These
results improve our understanding of factors driving obstacles faced
with the continuous cropping of sweetpotato, enabling future studies and
the development of technologies to overcome these obstacles.