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Balance between nitrogen use efficiency and cadmium tolerance in Brassica napus and Arabidopsis thaliana
Journal article   Peer reviewed

Balance between nitrogen use efficiency and cadmium tolerance in Brassica napus and Arabidopsis thaliana

Qiong Liao, Shao-Fen Jian, Hai-Xing Song, Chun-Yun Guan, Joe Eugene Lepo, Abdelbagi M. Ismail and Zhen-Hua Zhang
Plant science (Limerick), Vol.284, pp.57-66
07/2019
DOI: https://doi.org/10.1016/j.plantsci.2019.04.003
PMID: 31084879
Web of Science ID: WOS:000470042100008

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23 Times Cited - Web of Science

Abstract

•Reduced V-ATPase and V-PPase activity improved nitrogen use efficiency. •Reduced V-ATPase and V-PPase activity decreased Cd2+ tolerance.•Decreased NO3− vacuolar sequestration capacity (VSC) enhanced Atclca-2 Cd2+ VSC. •Enhanced Cd2+ VSC decreased NO3− VSC in AtCAX4-OE.•Regulating Cd2+ and NO3− vacuolar accumulation enhances NUE and Cd2+ tolerance. The transmembrane transport of NO3− and Cd2+ into plant cell vacuoles relies on the energy from their tonoplast proton pumps, V-ATPase and V-PPase. If the activity of these pumps is reduced, it results in less NO3− and Cd2+ being transported into the vacuoles, which contributes to better nitrogen use efficiency (NUE) and lower Cd2+ tolerance in plants. The physiological mechanisms that regulate the balance between NUE and Cd2+ tolerance remain unknown. In our study, two Brassica napus genotypes with differential NUEs, xiangyou 15 and 814, and Atclca-2 mutant and AtCAX4 over-expression line (AtCAX4-OE) of Arabidopsis thaliana, were used to investigate Cd2+ stress responses. We found that the Brassica napus genotype, with higher NUE, was more sensitive to Cd2+ stress. The AtCAX4-OE mutant, with higher Cd2+ vacuolar sequestration capacity (VSC), limited NO3− sequestration into root vacuoles and promoted NUE. Atclca-2 mutants, with decreased NO3− VSC, enhanced Cd2+ sequestration into root vacuoles and conferred greater Cd2+ tolerance than the WT. This may be due to the competition between Cd2+ andNO3− in the vacuoles for the energy provided by V-ATPase and V-PPase. Regulating the balance between Cd2+ and NO3− vacuolar accumulation by inhibiting the activity of CLCa transporter and increasing the activity of CAX4 transporter will simultaneously enhance both the NUE and Cd2+ tolerance of Brassica napus, essential for improving its Cd2+ phytoremediation potential.

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