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Article|01 Aug 2020|OPEN
Overexpression of phosphatidylserine synthase IbPSS1 affords cellular Na+ homeostasis and salt tolerance by activating plasma membrane Na+/H+ antiport activity in sweet potato roots
Yicheng Yu1, Ying Xuan1, Xiaofeng Bian2, Lei Zhang1, Zhiyuan Pan1, Meng Kou1,3, Qinghe Cao3, Zhonghou Tang3, Qiang Li3, Daifu Ma3, Zongyun Li1, & Jian Sun1,
1Jiangsu Key Laboratory of Phylogenomics and Comparative Genomics, School of Life Sciences, Jiangsu Normal University, 221116 Xuzhou, Jiangsu, China
2Institute of Food Crops, Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, 210014 Nanjing, China
3Xuzhou Institute of Agricultural Sciences in Jiangsu Xuhuai District, 221131 Xuzhou, Jiangsu Province, China

Horticulture Research 7,
Article number: 20131 (2020)
doi: 10.1038/hortres.2020.131
Views: 117

Received: 06 Apr 2020
Revised: 28 May 2020
Accepted: 03 Jun 2020
Published online: 01 Aug 2020

Abstract

Phosphatidylserine synthase (PSS)-mediated phosphatidylserine (PS) synthesis is crucial for plant development. However, little is known about the contribution of PSS to Na+ homeostasis regulation and salt tolerance in plants. Here, we cloned the IbPSS1 gene, which encodes an ortholog of Arabidopsis AtPSS1, from sweet potato (Ipomoea batatas (L.) Lam.). The transient expression of IbPSS1 in Nicotiana benthamiana leaves increased PS abundance. We then established an efficient Agrobacterium rhizogenes-mediated in vivo root transgenic system for sweet potato. Overexpression of IbPSS1 through this system markedly decreased cellular Na+ accumulation in salinized transgenic roots (TRs) compared with adventitious roots. The overexpression of IbPSS1 enhanced salt-induced Na+/H+ antiport activity and increased plasma membrane (PM) Ca2+-permeable channel sensitivity to NaCl and H2O2 in the TRs. We confirmed the important role of IbPSS1 in improving salt tolerance in transgenic sweet potato lines obtained from an Agrobacterium tumefaciens-mediated transformation system. Similarly, compared with the wild-type (WT) plants, the transgenic lines presented decreased Na+ accumulation, enhanced Na+ exclusion, and increased PM Ca2+-permeable channel sensitivity to NaCl and H2O2 in the roots. Exogenous application of lysophosphatidylserine triggered similar shifts in Na+ accumulation and Na+ and Ca2+ fluxes in the salinized roots of WT. Overall, this study provides an efficient and reliable transgenic method for functional genomic studies of sweet potato. Our results revealed that IbPSS1 contributes to the salt tolerance of sweet potato by enabling Na+ homeostasis and Na+ exclusion in the roots, and the latter process is possibly controlled by PS reinforcing Ca2+ signaling in the roots.