Exogenous 24-Epibrassinolide Improves Resistance to Leaf Spot Disease Through Antioxidant Regulation and Phenylpropanoid Metabolism in Oats

Leaf spot disease has become a significant limitation in oat production. 24-epibrassinolide (EBR), a highly active brassinosteroid, plays a significant role in enhancing plant immunity against various diseases by modulating physiological and molecular responses. However, the exact mechanisms by whic...

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Main Authors: Zheng Wang, Kuiju Niu, Guiqin Zhao, Yuehua Zhang, Jikuan Chai, Zeliang Ju
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Agronomy
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Online Access:https://www.mdpi.com/2073-4395/14/12/3035
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author Zheng Wang
Kuiju Niu
Guiqin Zhao
Yuehua Zhang
Jikuan Chai
Zeliang Ju
author_facet Zheng Wang
Kuiju Niu
Guiqin Zhao
Yuehua Zhang
Jikuan Chai
Zeliang Ju
author_sort Zheng Wang
collection DOAJ
description Leaf spot disease has become a significant limitation in oat production. 24-epibrassinolide (EBR), a highly active brassinosteroid, plays a significant role in enhancing plant immunity against various diseases by modulating physiological and molecular responses. However, the exact mechanisms by which exogenous EBR regulates plant defense to leaf spot disease are still largely unknown. In this study, we applied various concentrations of EBR (0, 0.01, 0.1, 1, and 10 mg·L<sup>−1</sup>) to the leaves of oat plants that were inoculated with the <i>Drechslera avenae</i> pathogen. The application of 1 mg·L<sup>−1</sup> EBR significantly decreased disease index and increased chlorophyll content under pathogen inoculation while also enhancing antioxidant enzyme (SOD, CAT, and APX) activity and reducing pathogen-induced O<sub>2</sub><sup>•−</sup> production rate and MDA content. Moreover, the enzymes associated with phenylpropanoid metabolism, such as PAL, C4H, and 4CL, were significantly activated by exogenous EBR. Our transcriptomic analyses further revealed that the combination of exogenous EBR and pathogen inoculation upregulated genes involved in signal transduction (BR, ABA, and MAPK), antioxidant enzyme defense systems, and phenylpropanoid and lignin-specific pathways, such as <i>BAS1</i>, <i>APX</i>, <i>GPX</i>, <i>PAL</i>, <i>C4H</i>, <i>4CL</i>, <i>CCR1</i>, and <i>CAD</i>. Together, these findings reveal that exogenous BR application can improve resistance to <i>Drechslera avenae</i>-induced leaf spot disease in oats by regulating antioxidant defense systems and phenylpropanoid metabolism, which may have the potential to control leaf spot disease in oat production.
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spelling doaj-art-439823aa2db84745b2c27f24c2d355ad2025-08-20T02:01:01ZengMDPI AGAgronomy2073-43952024-12-011412303510.3390/agronomy14123035Exogenous 24-Epibrassinolide Improves Resistance to Leaf Spot Disease Through Antioxidant Regulation and Phenylpropanoid Metabolism in OatsZheng Wang0Kuiju Niu1Guiqin Zhao2Yuehua Zhang3Jikuan Chai4Zeliang Ju5College of Pratacultural Science, Gansu Agricultural University, Lanzhou 730070, ChinaCollege of Pratacultural Science, Gansu Agricultural University, Lanzhou 730070, ChinaCollege of Pratacultural Science, Gansu Agricultural University, Lanzhou 730070, ChinaNational Center of Pratacultural Technology Innovation (Under Preparation), Hohhot 010050, ChinaCollege of Pratacultural Science, Gansu Agricultural University, Lanzhou 730070, ChinaKey Laboratory of Superior Forage Germplasm in the Qinghai-Tibetan Plateau, Academy of Animal Husbandry and Veterinary Sciences, Qinghai University, Xining 810016, ChinaLeaf spot disease has become a significant limitation in oat production. 24-epibrassinolide (EBR), a highly active brassinosteroid, plays a significant role in enhancing plant immunity against various diseases by modulating physiological and molecular responses. However, the exact mechanisms by which exogenous EBR regulates plant defense to leaf spot disease are still largely unknown. In this study, we applied various concentrations of EBR (0, 0.01, 0.1, 1, and 10 mg·L<sup>−1</sup>) to the leaves of oat plants that were inoculated with the <i>Drechslera avenae</i> pathogen. The application of 1 mg·L<sup>−1</sup> EBR significantly decreased disease index and increased chlorophyll content under pathogen inoculation while also enhancing antioxidant enzyme (SOD, CAT, and APX) activity and reducing pathogen-induced O<sub>2</sub><sup>•−</sup> production rate and MDA content. Moreover, the enzymes associated with phenylpropanoid metabolism, such as PAL, C4H, and 4CL, were significantly activated by exogenous EBR. Our transcriptomic analyses further revealed that the combination of exogenous EBR and pathogen inoculation upregulated genes involved in signal transduction (BR, ABA, and MAPK), antioxidant enzyme defense systems, and phenylpropanoid and lignin-specific pathways, such as <i>BAS1</i>, <i>APX</i>, <i>GPX</i>, <i>PAL</i>, <i>C4H</i>, <i>4CL</i>, <i>CCR1</i>, and <i>CAD</i>. Together, these findings reveal that exogenous BR application can improve resistance to <i>Drechslera avenae</i>-induced leaf spot disease in oats by regulating antioxidant defense systems and phenylpropanoid metabolism, which may have the potential to control leaf spot disease in oat production.https://www.mdpi.com/2073-4395/14/12/3035oatleaf spot24-epibrassinolideantioxidant systemphenylpropanoid metabolism
spellingShingle Zheng Wang
Kuiju Niu
Guiqin Zhao
Yuehua Zhang
Jikuan Chai
Zeliang Ju
Exogenous 24-Epibrassinolide Improves Resistance to Leaf Spot Disease Through Antioxidant Regulation and Phenylpropanoid Metabolism in Oats
Agronomy
oat
leaf spot
24-epibrassinolide
antioxidant system
phenylpropanoid metabolism
title Exogenous 24-Epibrassinolide Improves Resistance to Leaf Spot Disease Through Antioxidant Regulation and Phenylpropanoid Metabolism in Oats
title_full Exogenous 24-Epibrassinolide Improves Resistance to Leaf Spot Disease Through Antioxidant Regulation and Phenylpropanoid Metabolism in Oats
title_fullStr Exogenous 24-Epibrassinolide Improves Resistance to Leaf Spot Disease Through Antioxidant Regulation and Phenylpropanoid Metabolism in Oats
title_full_unstemmed Exogenous 24-Epibrassinolide Improves Resistance to Leaf Spot Disease Through Antioxidant Regulation and Phenylpropanoid Metabolism in Oats
title_short Exogenous 24-Epibrassinolide Improves Resistance to Leaf Spot Disease Through Antioxidant Regulation and Phenylpropanoid Metabolism in Oats
title_sort exogenous 24 epibrassinolide improves resistance to leaf spot disease through antioxidant regulation and phenylpropanoid metabolism in oats
topic oat
leaf spot
24-epibrassinolide
antioxidant system
phenylpropanoid metabolism
url https://www.mdpi.com/2073-4395/14/12/3035
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