Comparative Analysis of Ca<sup>2</sup><sup>+</sup>/Cation Antiporter Gene Family in <i>Rosa roxburghii</i> and Enhanced Calcium Stress Tolerance via Heterologous Expression of RrCAX1a in Tobacco
<i>Rosa roxburghii</i>, a calciphilic species native to the mountainous regions of Southwest China, is renowned for its high vitamin C and bioactive components, making it valuable for culinary and medicinal uses. This species exhibits remarkable tolerance to the high-calcium conditions t...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Plants |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2223-7747/13/24/3582 |
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| Summary: | <i>Rosa roxburghii</i>, a calciphilic species native to the mountainous regions of Southwest China, is renowned for its high vitamin C and bioactive components, making it valuable for culinary and medicinal uses. This species exhibits remarkable tolerance to the high-calcium conditions typical of karst terrains. However, the underlying mechanisms of this calcium resilience remain unclear. The Ca<sup>2</sup><sup>+</sup>/cation antiporter (CaCA) superfamily plays a vital role in the transport of Ca<sup>2</sup><sup>+</sup> and other cations and is crucial for plant tolerance to metal stress. However, the roles and evolutionary significance of the CaCA superfamily members in <i>R. roxburghii</i> remain poorly understood. This study identified 22 CaCA superfamily genes in <i>R. roxburghii</i>, categorized into four subfamilies. The gene structures of these <i>RrCaCAs</i> show considerable conservation across related species. Selection pressure analysis revealed that all <i>RrCaCAs</i> are subject to purifying selection. The promoter regions of these genes contain numerous hormone-responsive and stress-related elements. qRT-PCR analyses demonstrated that H<sup>+</sup>/cation exchanger (CAX) <i>RrCAX1a</i> and <i>RrCAX3a</i> were highly responsive to Ca<sup>2</sup><sup>+</sup> stress, cation/Ca<sup>2</sup><sup>+</sup> exchanger (CCX) <i>RrCCX4</i> to Mg<sup>2</sup><sup>+</sup> stress, and <i>RrCCX11a</i> to Na<sup>+</sup> stress. Subcellular localization indicated that <i>RrCAX1a</i> is localized to the plant cell membrane, and its stable transformation in tobacco confirmed its ability to confer enhanced resistance to heavy Ca<sup>2</sup><sup>+</sup> stresses, highlighting its crucial role in the high-calcium tolerance mechanisms of <i>R. roxburghii</i>. This research establishes a foundation for further molecular-level functional analyses of the adaptation mechanisms of <i>R. roxburghii</i> to high-calcium environments. |
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| ISSN: | 2223-7747 |