SC35-mediated bZIP49 splicing regulates K⁺ channel AKT1 for salt stress adaptation in poplar

Abstract Soil salinization threatens plant distribution, crop yields, and ecosystem stability. In response, plants activate potassium (K+) signaling to maintain Na⁺/K⁺ balance, though the mechanisms regulating K⁺ uptake under salt stress remain poorly understood. This study identified two splice var...

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Main Authors: Xiao Liu, Yu Bao, Man-Yu Zhang, Han Zhang, Meng-Xue Niu, Shu-Jing Liu, Mei-Ying Liu, Meng-Bo Huang, Chao Liu, Weilun Yin, Hou-Ling Wang, Xinli Xia
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-62448-9
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author Xiao Liu
Yu Bao
Man-Yu Zhang
Han Zhang
Meng-Xue Niu
Shu-Jing Liu
Mei-Ying Liu
Meng-Bo Huang
Chao Liu
Weilun Yin
Hou-Ling Wang
Xinli Xia
author_facet Xiao Liu
Yu Bao
Man-Yu Zhang
Han Zhang
Meng-Xue Niu
Shu-Jing Liu
Mei-Ying Liu
Meng-Bo Huang
Chao Liu
Weilun Yin
Hou-Ling Wang
Xinli Xia
author_sort Xiao Liu
collection DOAJ
description Abstract Soil salinization threatens plant distribution, crop yields, and ecosystem stability. In response, plants activate potassium (K+) signaling to maintain Na⁺/K⁺ balance, though the mechanisms regulating K⁺ uptake under salt stress remain poorly understood. This study identified two splice variants of the bZIP49 transcription factor in Populus tomentosa: unspliced “bZIP49L” and spliced “bZIP49S”. bZIP49S, the active form under salt stress, reduces salt tolerance when overexpressed, while bzip49cr knockout enhances it. The serine/arginine-rich splicing factor SC35 was identified as a regulator of bZIP49 mRNA splicing through a self-developed experimental method, and its overexpression enhances salt sensitivity. bZIP49S inhibits the K+ transporter AKT1 by binding its promoter, and AKT1 loss in bzip49cr mutant limits K+ influx and reduces salt tolerance. Under salt stress, the E2 ubiquitin-conjugating enzyme UBC32 promotes SC35 degradation via ubiquitination, lowering bZIP49S levels and alleviating the inhibition of AKT1. This facilitates K⁺ uptake, restores Na⁺/K⁺ balance, and improves salt tolerance. Our study highlights the critical role of bZIP49 splicing and the “UBC32-SC35-bZIP49-AKT1” module in modulating Na⁺/K⁺ balance under salt stress in poplar.
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institution Kabale University
issn 2041-1723
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publishDate 2025-08-01
publisher Nature Portfolio
record_format Article
series Nature Communications
spelling doaj-art-12d27f6d84344d91b3e1b3d422d412cf2025-08-20T03:46:23ZengNature PortfolioNature Communications2041-17232025-08-0116111510.1038/s41467-025-62448-9SC35-mediated bZIP49 splicing regulates K⁺ channel AKT1 for salt stress adaptation in poplarXiao Liu0Yu Bao1Man-Yu Zhang2Han Zhang3Meng-Xue Niu4Shu-Jing Liu5Mei-Ying Liu6Meng-Bo Huang7Chao Liu8Weilun Yin9Hou-Ling Wang10Xinli Xia11State Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityState Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityState Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityState Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityState Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityState Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityState Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityState Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityState Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityState Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityState Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityState Key Laboratory of Tree Genetics and Breeding, College of Biological Sciences and Technology, Beijing Forestry UniversityAbstract Soil salinization threatens plant distribution, crop yields, and ecosystem stability. In response, plants activate potassium (K+) signaling to maintain Na⁺/K⁺ balance, though the mechanisms regulating K⁺ uptake under salt stress remain poorly understood. This study identified two splice variants of the bZIP49 transcription factor in Populus tomentosa: unspliced “bZIP49L” and spliced “bZIP49S”. bZIP49S, the active form under salt stress, reduces salt tolerance when overexpressed, while bzip49cr knockout enhances it. The serine/arginine-rich splicing factor SC35 was identified as a regulator of bZIP49 mRNA splicing through a self-developed experimental method, and its overexpression enhances salt sensitivity. bZIP49S inhibits the K+ transporter AKT1 by binding its promoter, and AKT1 loss in bzip49cr mutant limits K+ influx and reduces salt tolerance. Under salt stress, the E2 ubiquitin-conjugating enzyme UBC32 promotes SC35 degradation via ubiquitination, lowering bZIP49S levels and alleviating the inhibition of AKT1. This facilitates K⁺ uptake, restores Na⁺/K⁺ balance, and improves salt tolerance. Our study highlights the critical role of bZIP49 splicing and the “UBC32-SC35-bZIP49-AKT1” module in modulating Na⁺/K⁺ balance under salt stress in poplar.https://doi.org/10.1038/s41467-025-62448-9
spellingShingle Xiao Liu
Yu Bao
Man-Yu Zhang
Han Zhang
Meng-Xue Niu
Shu-Jing Liu
Mei-Ying Liu
Meng-Bo Huang
Chao Liu
Weilun Yin
Hou-Ling Wang
Xinli Xia
SC35-mediated bZIP49 splicing regulates K⁺ channel AKT1 for salt stress adaptation in poplar
Nature Communications
title SC35-mediated bZIP49 splicing regulates K⁺ channel AKT1 for salt stress adaptation in poplar
title_full SC35-mediated bZIP49 splicing regulates K⁺ channel AKT1 for salt stress adaptation in poplar
title_fullStr SC35-mediated bZIP49 splicing regulates K⁺ channel AKT1 for salt stress adaptation in poplar
title_full_unstemmed SC35-mediated bZIP49 splicing regulates K⁺ channel AKT1 for salt stress adaptation in poplar
title_short SC35-mediated bZIP49 splicing regulates K⁺ channel AKT1 for salt stress adaptation in poplar
title_sort sc35 mediated bzip49 splicing regulates k⁺ channel akt1 for salt stress adaptation in poplar
url https://doi.org/10.1038/s41467-025-62448-9
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