Continuous Cropping and Natural Fallow Practices Affect Tobacco Fitness
and Soil Microbiomes
Abstract
Natural fallow practice has been identified as an effective way to
overcome obstacles of continuous cropping. However, how the resulting
soil microbial changes impact plant fitness, and how the
context-specific differences diverge from those caused by continuous
cropping remain largely unknown. This study used the third-year
continuous tobacco cropping soil (CCS) and natural fallow soil (FS) to
cultivate Nicotiana tabacum. The influences of soil microorganisms on
the fitness of N. tabacum were assessed by reassembling soil microbial
communities. Then, the bacterial and fungal community assembly of the
bulk soil and the rhizosphere were characterized using amplicon
sequencing and statistical analysis. The results indicated that soil
microorganisms play more important roles for plant fitness for N.
tabacum grown in FS compared with CCS. Moreover, the abiotic context of
FS exerts stronger effects compared with those of CCS for the reassembly
of soil microbiomes. Comparative analysis identified the
context-specific microbial clades and the differential strength of
rhizosphere effects. In conclusion, this paper provides context-specific
microbial evidence, which may unravel the potential mechanism underlying
the different response of N. tabacum to changes of soil microbiomes
induced by natural fallow and continuous cropping practices.