<i>IPA1</i> Negatively Regulates Early Rice Seedling Development by Interfering with Starch Metabolism via the GA and <i>WRKY</i> Pathways

<i>IPA1</i> Negatively Regulates Early Rice Seedling Development by Interfering with Starch Metabolism via the GA and <i>WRKY</i> Pathways

<i>Ideal Plant Architecture 1 (IPA1)</i> encodes SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 14 (SPL14) with a pleiotropic effect on regulating rice development and biotic stress responses. To investigate the role of <i>IPA1</i> in early seedling development, we developed a pair o...

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Bibliographic Details
Main Authors: Yonggang He, Menghao Zhu, Zhihui Li, Shan Jiang, Zijun He, Shuang Xu, Xiangsong Chen, Zhongli Hu, Zhihong Zhang
Format: Article
Language:English
Published: MDPI AG 2021-06-01
Series:International Journal of Molecular Sciences
Subjects:
rice (<i>Oryza sativa</i> L.)
seed germination
<i>IPA1</i>/<i>OsSPL14</i>
gibberellin (GA)
<i>WRKY</i>
Online Access:https://www.mdpi.com/1422-0067/22/12/6605
Description
Summary:<i>Ideal Plant Architecture 1 (IPA1)</i> encodes SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 14 (SPL14) with a pleiotropic effect on regulating rice development and biotic stress responses. To investigate the role of <i>IPA1</i> in early seedling development, we developed a pair of <i>IPA1</i>/<i>ipal</i>-NILs and found that seed germination and early seedling growth were retarded in the <i>ipa1</i>-NIL. Analysis of the soluble sugar content, activity of amylase, and expression of the <i>α</i>-amylase genes revealed that the starch metabolism was weakened in the <i>ipa1</i>-NIL germinating seeds. Additionally, the content of bioactive gibberellin (GA) was significantly lower than that in the <i>IPA1</i>-NIL seeds at 48 h of imbibition. Meanwhile, the expression of GA synthesis-related gene <i>OsGA20ox1</i> was downregulated, whereas the expression of GA inactivation-related genes was upregulated in <i>ipa1</i>-NIL seeds. In addition, the expression of <i>OsWRKY51</i> and <i>OsWRKY71</i> was significantly upregulated in <i>ipa1</i>-NIL seeds. Using transient dual-luciferase and yeast one-hybrid assays, IPA1 was found to directly activate the expression of <i>OsWRKY51</i> and <i>OsWRKY71</i>, which would interfere with the binding affinity of GA-induced transcription factor OsGAMYB to inhibit the expression of <i>α</i>-amylase genes. In summary, our results suggest that <i>IPA1</i> negatively regulates seed germination and early seedling growth by interfering with starch metabolism via the GA and <i>WRKY</i> pathways.
ISSN:1661-6596
1422-0067

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