Beneficial rhizobacterium Bacillus velezensis SQR9 regulates plant nitrogen uptake via endogenous signaling pathway

Yu Chen; Yucong Li; Yansong Fu; Letian Jia; Lun Li; Zhihui Xu; Nan Zhang; Yunpeng Liu; Xiaorong Fan; Wei Xuan; Guohua Xu; Ruifu Zhang

doi:10.1093/jxb/erae125

Beneficial rhizobacterium Bacillus velezensis SQR9 regulates plant nitrogen uptake via endogenous signaling pathway

J Exp Bot. 2024 Mar 18:erae125. doi: 10.1093/jxb/erae125. Online ahead of print.

Authors

Yu Chen¹, Yucong Li¹, Yansong Fu¹, Letian Jia², Lun Li², Zhihui Xu¹, Nan Zhang¹, Yunpeng Liu³, Xiaorong Fan², Wei Xuan², Guohua Xu², Ruifu Zhang¹

Affiliations

¹ Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing 210095, China.
² State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing 210095, China.
³ State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.

PMID: 38497798
DOI: 10.1093/jxb/erae125

Abstract

Nitrogen fertilizer is widely used in agriculture to boost crop yields, plant growth-promoting rhizobacteria (PGPRs) can increase plant nitrogen use efficiency through nitrogen fixation and organic nitrogen mineralization. However, it is not known if they can activate the plant uptake of nitrogen. In this study, we investigated the effects of a PGPR strain Bacillus velezensis SQR9-emitted volatile compounds (VCs) on plant nitrogen uptake. Strain SQR9 VCs promoted nitrogen accumulation in both rice and Arabidopsis. In addition, isotope labeling experiments showed that strain SQR9 VCs promoted the absorption of nitrate and ammonium. Several key nitrogen uptake genes were up-regulated by strain SQR9 VCs, such as AtNRT2.1 in Arabidopsis and OsNAR2.1, OsNRT2.3a and OsAMT1 family members in rice, and the deletion of these genes compromised the promoting effect of SQR9 VCs on plant nitrogen absorption. Furthermore, the calcium (Ca2+) and transcription factor NIN-LIKE PROTEIN 7 play an important role in strain SQR9 VCs-promoted nitrate uptake. Taken together, our results suggest that PGPRs can promote nitrogen uptake through regulating the plant's endogenous signaling and nitrogen transport pathways.

Keywords: AtNRT2.1; Bacillus velezensis; nitrate uptake; nitrogen transport pathway; plant growth-promoting rhizobacteria; volatile compounds.