Soybean nodulation shapes the rhizosphere microbiome to increase rapeseed yield

Area of Science:

• Agricultural Science
• Soil Microbiology
• Plant Biology

Background:

• Crop rotation is vital for soil health and productivity.
• Soybeans are key in crop rotation due to nitrogen fixation via root symbiosis.
• Soybean-rapeseed rotation is effective in China's Yangtze River Basin, but mechanisms are unclear.

Purpose of the Study:

• To elucidate the mechanisms by which prior soybean cultivation improves subsequent rapeseed growth.
• To understand the role of soybean nodulation genotypes in root exudation and rhizosphere microbiome.

Main Methods:

• Conducted soybean-rapeseed rotation trials using soybeans with varying nodulation genotypes.
• Analyzed soybean root secretome and soil rhizosphere microbiome composition.
• Evaluated the impact of soybean cultivation on rapeseed growth and yield.

Main Results:

• Soybean-rapeseed rotation significantly increased rapeseed growth and yield, particularly with supernodulating soybeans.
• Soybean nodulation influenced root exudates, altering rhizosphere bacterial communities.
• Supernodulating soybeans promoted Sphingomonadaceae growth via oleic acid and cis-4-hydroxy-D-proline secretion, attracting these bacteria.
• Exogenous application of Sphingomonadaceae and/or rhizobia enhanced rapeseed growth.

Conclusions:

• Previous soybean cultivation is critical for enhancing rapeseed yield, mediated by Sphingomonadaceae bacteria and rhizobia.
• Soybean nodulation impacts rhizosphere bacterial dynamics, underscoring its significance in sustainable agriculture.
• This study reveals key microbial mechanisms driving the success of soybean-rapeseed crop rotation systems.