A Series of Novel Alleles of <i>Ehd2</i> Modulating Heading and Salt Tolerance in Rice
Rice (<i>Oryza sativa</i> L.) is a staple crop for nearly half of the global population and one of China’s most extensively cultivated cereals. Heading date, a critical agronomic trait, determines the regional and seasonal adaptability of rice varieties. In this study, a series of mutant...
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| Main Authors: | , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Plants |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2223-7747/14/2/297 |
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| Summary: | Rice (<i>Oryza sativa</i> L.) is a staple crop for nearly half of the global population and one of China’s most extensively cultivated cereals. Heading date, a critical agronomic trait, determines the regional and seasonal adaptability of rice varieties. In this study, a series of mutants (<i>elh5</i> to <i>elh12</i>) exhibiting extremely late heading under both long-day (LD) and short-day (SD) conditions were identified from an ethyl methanesulfonate (EMS) mutant library. Using MutMap and map-based cloning, the causative gene was identified as a novel allele of <i>Ehd2</i>/<i>OsID1</i>/<i>RID1</i>/<i>Ghd10</i>. Functional validation through CRISPR/Cas9 knockout and complementation assays confirmed its role in regulating heading. The <i>elh6</i> mutation was found to cause intron retention due to alternative splicing. <i>Ehd2</i> encodes a Cys-2/His-2-type zinc finger transcription factor with an IDD domain and transcriptional activity in yeast. Its expression peaks in developing leaves before heading and spikes during reproductive conversion. In <i>elh6</i> mutants, delayed heading resulted from downregulating the <i>Ehd1</i>-<i>Hd3a</i> pathway genes. Salinity stress significantly hampers rice growth and productivity. Transcriptomic analysis of <i>elh10</i> and ZH8015 seedlings exposed to salt stress for 24 h identified 5150 differentially expressed genes (DEGs) at the seedling stage, predominantly linked to stress response pathways. <i>Ehd2</i> was revealed as a modulator of salt tolerance, likely through the regulation of ion transport, enzyme activity, and antioxidant systems. This study establishes <i>Ehd2</i> as a pivotal factor in promoting heading while negatively regulating salt tolerance in rice. |
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| ISSN: | 2223-7747 |