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Article|30 Dec 2022|OPEN
RcbHLH59-RcPRs module enhances salinity stress tolerance by balancing Na+/K+ through callose deposition in rose (Rosa chinensis)
Lin Su1 , Yichang Zhang1 , Shuang Yu1 , Lifang Geng1 , Shang Lin1 , Lin Ouyang2 , and Xinqiang Jiang,1 ,
1College of Landscape Architecture and Forestry, Qingdao Agricultural University, Qingdao, 266000, China
2Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, 610000, China
*Corresponding author. E-mail: ouyanglin@caas.cn,jiangxinqiang8@163.com

Horticulture Research 10,
Article number: uhac291 (2023)
doi: https://doi.org/10.1093/hr/uhac291
Views: 257

Received: 30 Aug 2022
Accepted: 22 Dec 2022
Published online: 30 Dec 2022

Abstract

Basic helix–loop–helix (bHLH) proteins play pivotal roles in plant growth, development, and stress responses. However, the molecular and functional properties of bHLHs have not been fully characterized. In this study, a novel XI subgroup of the bHLH protein gene RcbHLH59 was isolated and identified in rose (Rosa sp.). This gene was induced by salinity stress in both rose leaves and roots, and functioned as a transactivator. Accordingly, silencing RcbHLH59 affected the antioxidant system, Na +/K + balance, and photosynthetic system, thereby reducing salt tolerance, while the transient overexpression of RcbHLH59 improved salinity stress tolerance. Additionally, RcbLHLH59 was found to regulate the expression of sets of pathogenesis-related (PR) genes in RcbHLH59-silenced (TRV-RcbHLH59) and RcbHLH59-overexpressing (RcbHLH59-OE) rose plants. The RcPR4/1 and RcPR5/1 transcript levels showed opposite changes in the TRV-RcbHLH59 and RcbHLH59-OE lines, suggesting that these two genes are regulated by RcbHLH59. Further analysis revealed that RcbHLH59 binds to the promoters of RcPR4/1 and RcPR5/1, and that the silencing of RcPR4/1 or RcPR5/1 led to decreased tolerance to salinity stress. Moreover, callose degradation- and deposition-related genes were impaired in RcPR4/1- or RcPR5/1-silenced plants, which displayed a salt tolerance phenotype by balancing the Na+/K+ ratio through callose deposition. Collectively, our data highlight a new RcbLHLH59-RcPRs module that positively regulates salinity stress tolerance by balancing Na+/K+ and through callose deposition in rose plants.