Brassinosteroid Enhances Cucumber Stress Tolerance to NaHCO<sub>3</sub> by Modulating Nitrogen Metabolism, Ionic Balance and Phytohormonal Response
Under NaHCO<sub>3</sub> stress, exogenous 24-epibrassinolide (EBR) markedly alleviated Na<sup>+</sup> accumulation in cucumber plants, thereby decreasing the Na<sup>+</sup>/K<sup>+</sup>, Na<sup>+</sup>/Mg<sup>2+</sup>, and Na&l...
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2024-12-01
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| author | Wenjing Nie Biao Gong Dan Wen Peng Qiao Hongen Guo Qinghua Shi |
| author_facet | Wenjing Nie Biao Gong Dan Wen Peng Qiao Hongen Guo Qinghua Shi |
| author_sort | Wenjing Nie |
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| description | Under NaHCO<sub>3</sub> stress, exogenous 24-epibrassinolide (EBR) markedly alleviated Na<sup>+</sup> accumulation in cucumber plants, thereby decreasing the Na<sup>+</sup>/K<sup>+</sup>, Na<sup>+</sup>/Mg<sup>2+</sup>, and Na<sup>+</sup>/Ca<sup>2+</sup> ratios. This mitigation was accompanied by elevated concentrations of K<sup>+</sup>, Ca<sup>2+</sup>, and Mg<sup>2+</sup>, as well as enhanced expression of the <i>NHX</i> and <i>SOS1</i> genes. In addition, the activities of plasma membrane H<sup>+</sup>-ATPase, vesicular membrane H<sup>+</sup>-ATPase, and vesicular membrane H<sup>+</sup>-PPase were significantly increased, contributing to the maintenance of ionic balance in cucumber plants. NaHCO<sub>3</sub> stress disrupted nitrogen metabolism, as evidenced by reductions in the activities of NR, GS, GOGAT, GOT, and GPT, along with altered GDH activity. These disruptions led to an accumulation of NH<sub>4</sub><sup>+</sup> and substantial decreases in NO<sub>3</sub><sup>−</sup>-N and total nitrogen content. Exogenous EBR alleviated these effects by enhancing the activities of NR, GS, GOGAT, GOT, and GPT, countering the prolonged suppression of GDH activity, and restoring NO<sub>3</sub><sup>−</sup>-N and total nitrogen levels. Consequently, EBR application reduced NH<sub>4</sub><sup>+</sup> toxicity induced by alkali stress. Additionally, NaHCO<sub>3</sub> stress increased ABA accumulation while decreasing IAA and GA<sub>3</sub> content in cucumber seedlings. In contrast, exogenous EBR application elevated IAA and GA<sub>3</sub> levels and increased the IAA/ABA and GA<sub>3</sub>/ABA ratios, thus maintaining hormonal equilibrium under alkali stress. Collectively, these findings highlight that exogenous EBR enhances the alkaline tolerance of cucumber plants by regulating nitrogen metabolism, ion homeostasis, and phytohormonal responses. |
| format | Article |
| id | doaj-art-225318e21dd64cc0bf8f08ced23df3f6 |
| institution | Kabale University |
| issn | 2223-7747 |
| language | English |
| publishDate | 2024-12-01 |
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| series | Plants |
| spelling | doaj-art-225318e21dd64cc0bf8f08ced23df3f62025-01-10T13:19:41ZengMDPI AGPlants2223-77472024-12-011418010.3390/plants14010080Brassinosteroid Enhances Cucumber Stress Tolerance to NaHCO<sub>3</sub> by Modulating Nitrogen Metabolism, Ionic Balance and Phytohormonal ResponseWenjing Nie0Biao Gong1Dan Wen2Peng Qiao3Hongen Guo4Qinghua Shi5Yantai Key Laboratory of Evaluation and Utilization of Silkworm Functional Substances, Yantai Engineering Research Center of Plant Stem Cell Targeted Breeding, Shandong Engineering Research Center of Functional Crop Germplasm Innovation and Cultivation Utilization, Shandong Institute of Sericulture, Yantai 264001, ChinaStage Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271018, ChinaYantai Key Laboratory of Evaluation and Utilization of Silkworm Functional Substances, Yantai Engineering Research Center of Plant Stem Cell Targeted Breeding, Shandong Engineering Research Center of Functional Crop Germplasm Innovation and Cultivation Utilization, Shandong Institute of Sericulture, Yantai 264001, ChinaYantai Key Laboratory of Evaluation and Utilization of Silkworm Functional Substances, Yantai Engineering Research Center of Plant Stem Cell Targeted Breeding, Shandong Engineering Research Center of Functional Crop Germplasm Innovation and Cultivation Utilization, Shandong Institute of Sericulture, Yantai 264001, ChinaYantai Key Laboratory of Evaluation and Utilization of Silkworm Functional Substances, Yantai Engineering Research Center of Plant Stem Cell Targeted Breeding, Shandong Engineering Research Center of Functional Crop Germplasm Innovation and Cultivation Utilization, Shandong Institute of Sericulture, Yantai 264001, ChinaStage Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271018, ChinaUnder NaHCO<sub>3</sub> stress, exogenous 24-epibrassinolide (EBR) markedly alleviated Na<sup>+</sup> accumulation in cucumber plants, thereby decreasing the Na<sup>+</sup>/K<sup>+</sup>, Na<sup>+</sup>/Mg<sup>2+</sup>, and Na<sup>+</sup>/Ca<sup>2+</sup> ratios. This mitigation was accompanied by elevated concentrations of K<sup>+</sup>, Ca<sup>2+</sup>, and Mg<sup>2+</sup>, as well as enhanced expression of the <i>NHX</i> and <i>SOS1</i> genes. In addition, the activities of plasma membrane H<sup>+</sup>-ATPase, vesicular membrane H<sup>+</sup>-ATPase, and vesicular membrane H<sup>+</sup>-PPase were significantly increased, contributing to the maintenance of ionic balance in cucumber plants. NaHCO<sub>3</sub> stress disrupted nitrogen metabolism, as evidenced by reductions in the activities of NR, GS, GOGAT, GOT, and GPT, along with altered GDH activity. These disruptions led to an accumulation of NH<sub>4</sub><sup>+</sup> and substantial decreases in NO<sub>3</sub><sup>−</sup>-N and total nitrogen content. Exogenous EBR alleviated these effects by enhancing the activities of NR, GS, GOGAT, GOT, and GPT, countering the prolonged suppression of GDH activity, and restoring NO<sub>3</sub><sup>−</sup>-N and total nitrogen levels. Consequently, EBR application reduced NH<sub>4</sub><sup>+</sup> toxicity induced by alkali stress. Additionally, NaHCO<sub>3</sub> stress increased ABA accumulation while decreasing IAA and GA<sub>3</sub> content in cucumber seedlings. In contrast, exogenous EBR application elevated IAA and GA<sub>3</sub> levels and increased the IAA/ABA and GA<sub>3</sub>/ABA ratios, thus maintaining hormonal equilibrium under alkali stress. Collectively, these findings highlight that exogenous EBR enhances the alkaline tolerance of cucumber plants by regulating nitrogen metabolism, ion homeostasis, and phytohormonal responses.https://www.mdpi.com/2223-7747/14/1/80cucumberalkaline stressbrassinolideionic balancenitrogen metabolismphytohormonal balance |
| spellingShingle | Wenjing Nie Biao Gong Dan Wen Peng Qiao Hongen Guo Qinghua Shi Brassinosteroid Enhances Cucumber Stress Tolerance to NaHCO<sub>3</sub> by Modulating Nitrogen Metabolism, Ionic Balance and Phytohormonal Response Plants cucumber alkaline stress brassinolide ionic balance nitrogen metabolism phytohormonal balance |
| title | Brassinosteroid Enhances Cucumber Stress Tolerance to NaHCO<sub>3</sub> by Modulating Nitrogen Metabolism, Ionic Balance and Phytohormonal Response |
| title_full | Brassinosteroid Enhances Cucumber Stress Tolerance to NaHCO<sub>3</sub> by Modulating Nitrogen Metabolism, Ionic Balance and Phytohormonal Response |
| title_fullStr | Brassinosteroid Enhances Cucumber Stress Tolerance to NaHCO<sub>3</sub> by Modulating Nitrogen Metabolism, Ionic Balance and Phytohormonal Response |
| title_full_unstemmed | Brassinosteroid Enhances Cucumber Stress Tolerance to NaHCO<sub>3</sub> by Modulating Nitrogen Metabolism, Ionic Balance and Phytohormonal Response |
| title_short | Brassinosteroid Enhances Cucumber Stress Tolerance to NaHCO<sub>3</sub> by Modulating Nitrogen Metabolism, Ionic Balance and Phytohormonal Response |
| title_sort | brassinosteroid enhances cucumber stress tolerance to nahco sub 3 sub by modulating nitrogen metabolism ionic balance and phytohormonal response |
| topic | cucumber alkaline stress brassinolide ionic balance nitrogen metabolism phytohormonal balance |
| url | https://www.mdpi.com/2223-7747/14/1/80 |
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