Shandong Science

   

Effects of B418 on the yield of continuously cropped Rape (Brassica chinensis L.) and on the nitrogen-cycling and carbon-fixation gene cbbL in rhizosphere soils

WANG Yilian1, HU Jindong1, HUANG Dingli2, XU Weisheng3, YANG Hetong1, LI Jishun1*, HE Chunyu4   

  1. 1. The Collaborative Innovation Center of Yellow River Basin for Low-carbon Disposal and Resource Utilization of Organic Pollutants in Light Industry, Ecology Institute of Shandong Academy of Sciences, Qilu University of Technology (Shandong Academy of Sciences),Jinan,250103; 2. Weihai Yifeng Agricultural Science and Technology Co. , Ltd. Weihai, 264200;3. Forestry station of Zhuge Town, Yishui County, Shandong Province, Linyi 276422;4. Pharmacy College of Gansu University of Chinese Medicine, Lanzhou 730000
  • Received:2025-07-21 Accepted:2025-11-03 Online:2025-12-23
  • Contact: LI Jishun E-mail:sdyewu2@163.com

Abstract: To clarify how B418 alleviates the limitations imposed by continuous-cropping obstacle soils on rape production, a plot experiment was conducted to investigate the effects of exogenously applied B418 on the emergence, survival, and yield of rape, as well as on nitrogen transformation-related genes and carbon-fixation genes in the rhizosphere soil of continuously cropped rape (Brassica napus L.). Correlations between functional gene abundance and yield were also analyzed to provide a scientific basis for increasing the yield of continuously cropped vegetables. The results showed that in mildly secondary salinized obstacle soil I (pH 4.3, EC 1361 μs·cm?1) and severely secondary salinized obstacle soil II (pH 4.6, EC 2200 μs·cm?1), B418 significantly increased the emergence rate, survival rate, and yield of rape and increased the absolute abundance of the carbon-fixation gene cbbL in rhizosphere soil. In soil I, B418 treatment increased the abundance of the nitrogenase gene nifH and the ammonia monooxygenase gene amoA, but decreased the abundance of the nitrous oxide reductase gene nosZ. In soil II, B418 treatment increased the abundance of nifH while decreasing the abundance of amoA, the nitrite reductase genes nirK and nirS, and nosZ, with significant differences between treatments. These results indicate that exogenously added B418 can suppress rhizosphere nitrification and denitrification in continuously cropped rape. Correlation analysis showed that yield was positively correlated with the abundance of cbbL and nifH, negatively correlated with nirK, and significantly negatively correlated with the abundance of amoA, nirS, and nosZ. The abundance of amoA was extremely significantly positively correlated with that of nosZ, indicating that yield improvement in continuously cropped rape is closely related to rhizosphere microbial carbon-fixation and nitrogen-cycling capacities, as well as to the suppression of nitrification and denitrification.

Key words: Burkholderia vietnamiensisB418, continuous cropping obstacles, Brassica chinensisL, nitrogen-cycling genes, carbon-fixation gene abundance

CLC Number: 

  • S636.9

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