Dynamic root microbiome sustains soybean productivity under unbalanced fertilization

Area of Science:

• Microbiology
• Plant Science
• Agricultural Science

Background:

• Root-associated microbiomes are crucial for plant health and growth.
• Fertilizer application significantly impacts soil microbial communities and plant development.
• Quantitative changes in root-associated bacteria under specific fertilizer regimes remain poorly understood.

Purpose of the Study:

• To investigate the temporal dynamics of soybean root-associated bacteria under unbalanced fertilization.
• To assess the impact of long-term N, P, or K deficiency on microbial assembly and plant growth.
• To identify microbial communities with potential for sustainable agriculture.

Main Methods:

• Quantitative microbiome profiling (QMP) was employed to analyze root-associated bacteria in soybean.
• Temporal sampling was conducted throughout plant development under different fertilizer treatments (N, P, K deficient).
• Bacterial community composition, load, and succession patterns were examined.

Main Results:

• Root-associated bacterial communities showed significant succession during soybean development, with increased loads at later stages, especially Bacteroidetes.
• Unbalanced fertilization markedly affected bacterial assembly; N deficiency caused community divergence, while P deficiency reduced bacterial load and turnover.
• A synthetic community (SynCom) derived from low-N enriched clusters promoted plant growth and stabilized soybean productivity.

Conclusions:

• Long-term unbalanced fertilization profoundly alters the soybean root microbiome's quantitative dynamics.
• Nitrogen deficiency has a unique impact on rhizosphere bacterial assembly, distinct from P or K deficiency.
• Specific microbial clusters, particularly those thriving in low-N conditions, hold promise for developing sustainable agricultural strategies to enhance crop productivity.