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Lv S, Wang L, Zhang X, Li X, Fan L, Xu Y, Zhao Y, Xie H, Sawchuk MG, Scarpella E, Qiu QS. Arabidopsis NHX5 and NHX6 regulate PIN6-mediated auxin homeostasis and growth. J Plant Physiol 2020; 255:153305. [PMID: 33129075 DOI: 10.1016/j.jplph.2020.153305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/06/2020] [Accepted: 10/06/2020] [Indexed: 06/11/2023]
Abstract
NHX5 and NHX6, endosomal Na+,K+/H+ antiporters in Arabidopsis thaliana, play a vital role in growth and development. Our previous study has shown that NHX5 and NHX6 function as H+ leak to regulate auxin-mediated growth in Arabidopsis. In this report, we investigated the function of NHX5 and NHX6 in controlling PIN6-mediated auxin homeostasis and growth in Arabidopsis. Phenotypic analyses found that NHX5 and NHX6 were critical for the function of PIN6, an auxin transporter. We further showed that PIN6 depended on NHX5 and NHX6 in regulating auxin homeostasis. NHX5 and NHX6 were colocalized with PIN6, but they did not interact physically. The conserved acidic residues that are vital for the activity of NHX5 and NHX6 were critical for PIN6 function. Together, NHX5 and NHX6 may regulate PIN6 function by their transport activity.
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Affiliation(s)
- Shasha Lv
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China
| | - Lu Wang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China
| | - Xiao Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China
| | - Xiaojiao Li
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China
| | - Ligang Fan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China
| | - Yanli Xu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China
| | - Yingjia Zhao
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China
| | - Huichun Xie
- Qinghai Provincial Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Tibet Plateau, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810008, China
| | - Megan G Sawchuk
- Department of Biological Sciences, University of Alberta, CW-405 Biological Sciences Building, Edmonton AB T6G 2E9, Canada
| | - Enrico Scarpella
- Department of Biological Sciences, University of Alberta, CW-405 Biological Sciences Building, Edmonton AB T6G 2E9, Canada
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 73000, China.
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Zhang X, Li Z, Li X, Xu Y, Xie H, Qiu QS. CBL3 and CIPK18 are required for the function of NHX5 and NHX6 in mediating Li + homeostasis in Arabidopsis. J Plant Physiol 2020; 255:153295. [PMID: 33129077 DOI: 10.1016/j.jplph.2020.153295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/01/2020] [Accepted: 10/01/2020] [Indexed: 06/11/2023]
Abstract
Arabidopsis NHX5 and NHX6 are endosomal Na+,K+/H+ antiporters that function in mediating Na+, K+ and pH homeostasis. Here, we report that NHX5 and NHX6 mediate Li+ homeostasis in Arabidopsis. We found that the nhx5 nhx6 double mutant was defective in growth and had a high pale rate under Li+ stress; complementation with either NHX5 or NHX6 restored the growth of the double mutant under LiCl treatments. We further found that CBL3 and CIPK18 collaborate with NHX5 and NHX6 in controlling seedling growth. CBL3 and CIPK18 are involved in the NHX5- and NHX6-mediated response to Li+ stress but not to salt or low K+ stress. In addition, NHX5 and NHX6 coordinate NHX8, a plasma membrane antiporter, in mediating Li+ homeostasis. NHX8 may function differently from NHX5 and NHX6 in mediating Li+ homeostasis. NHX8 was not controlled by CBL3 and CIPK18. Overall, CBL3 and CIPK18 are required for the function of NHX5 and NHX6 in mediating Li+ homeostasis in Arabidopsis.
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Affiliation(s)
- Xiao Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Zhanchao Li
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Xiaojiao Li
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yanli Xu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Huichun Xie
- Qinghai Provincial Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Tibet Plateau, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810008, China
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
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Krishnamurthy P, Vishal B, Khoo K, Rajappa S, Loh CS, Kumar PP. Expression of AoNHX1 increases salt tolerance of rice and Arabidopsis, and bHLH transcription factors regulate AtNHX1 and At NHX6 in Arabidopsis. Plant Cell Rep 2019; 38:1299-1315. [PMID: 31350571 DOI: 10.1007/s00299-019-02450-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 07/22/2019] [Indexed: 05/17/2023]
Abstract
Expression of AoNHX1 from the mangrove Avicennia increases salt tolerance of rice and Arabidopsis, and specific bHLH transcription factors regulate AtNHX1 and AtNHX6 in Arabidopsis to mediate the salinity response. Improving crop plants to better tolerate soil salinity is a challenging task. Mangrove trees such as Avicennia officinalis have special adaptations to thrive in high salt conditions, which include subcellular compartmentalization of ions facilitated by specialized ion transporters. We identified and characterized two genes encoding Na+/H+ exchangers AoNHX1 and AoNHX6 from Avicennia. AoNHX1 was present in the tonoplast, while, AoNHX6 was localized to the ER and Golgi. Both NHXs were induced by NaCl treatment, with AoNHX1 showing high expression levels in the leaves and AoNHX6 in the seedling roots. Yeast deletion mutants (ena1-5Δ nha1Δ nhx1Δ and ena1-5Δ nha1Δ vnx1Δ) complemented with AoNHX1 and AoNHX6 showed increased tolerance to both NaCl and KCl. Expression of AoNHX1 and AoNHX6 in the corresponding Arabidopsis mutants conferred enhanced NaCl tolerance. The underlying molecular regulatory mechanism was investigated using AtNHX1 and AtNHX6 in Arabidopsis. We identified two basic helix-loop-helix (bHLH) transcription factors AtMYC2 and AtbHLH122 as the ABA-mediated upstream regulators of AtNHX1 and AtNHX6 by chromatin immunoprecipitation. Furthermore, expression of AtNHX1 and AtNHX6 transcripts was reduced in the atmyc2 and atbhlh122 mutants. Lastly, transgenic rice seedlings harboring pUBI::AoNHX1 showed enhanced salt tolerance, suggesting that this gene can be exploited for developing salt-tolerant crops.
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Affiliation(s)
- Pannaga Krishnamurthy
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
- NUS Environmental Research Institute (NERI), National University of Singapore, #02-01, T-Lab Building, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Bhushan Vishal
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
| | - Kaijie Khoo
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
| | - Sivamathini Rajappa
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
| | - Chiang-Shiong Loh
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
- NUS Environmental Research Institute (NERI), National University of Singapore, #02-01, T-Lab Building, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Prakash P Kumar
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore.
- NUS Environmental Research Institute (NERI), National University of Singapore, #02-01, T-Lab Building, 5A Engineering Drive 1, Singapore, 117411, Singapore.
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