Comprehensive Transcriptomics, Hormone Metabolomics, and Physiological Analysis Reveal the Mechanism of Exogenous GA<sub>4+7</sub> Breaking the Seed Dormancy in <i>Polygonatum cyrtonema</i> Hua

<i>Polygonatum cyrtonema</i> Hua <i>(P. cyrtonema)</i> is a medicinal plant with high pharmaceutical value. Due to morphological and physiological dormancy mechanisms in <i>P. cyrtonema</i> seeds, natural germination rates remain exceptionally low. This biological...

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Main Authors: Mi Qiu, Jionglan Wan, Chunxiang Hao, Zixin Zeng, Yalong Hu, Guoqun Yang, Hua Yang, Xiaoyun Zhou
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Horticulturae
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Online Access:https://www.mdpi.com/2311-7524/11/6/627
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Summary:<i>Polygonatum cyrtonema</i> Hua <i>(P. cyrtonema)</i> is a medicinal plant with high pharmaceutical value. Due to morphological and physiological dormancy mechanisms in <i>P. cyrtonema</i> seeds, natural germination rates remain exceptionally low. This biological constraint necessitates the development of protocols to shorten germination timelines and improve germination efficiency, which are critical requirements for advancing <i>P. cyrtonema</i> breeding programs. In this study, exogenous gibberellin A4 + A7 (GA<sub>4+7</sub>) was applied to break dormancy in <i>P. cyrtonema</i> seeds. Transcriptomic, hormone metabolomic, and physiological analyses were then employed to investigate the underlying mechanisms. Germination tests revealed that 50 mg·L<sup>−1</sup> GA<sub>4+7</sub> was the optimal concentration to break dormancy in <i>P. cyrtonema</i> seeds. Transcriptome analysis indicated that exogenous GA<sub>4+7</sub> induced the expression of genes involved in GA and ABA biosynthesis and signaling. A total of 19 differential hormone metabolites were identified through hormone metabolomics, with significantly increased levels of active GA<sub>1</sub> and GA<sub>4</sub>, but decreased levels of ABA content. These findings were consistent with the up-regulation of transcript levels of GA biosynthesis-related genes and the down-regulation of ABA biosynthesis-related genes, which resulted in an increase in active GA/ABA ratio. At the same time, it was found that exogenous GA<sub>4+7</sub> treatment induced sucrose and starch metabolism and pectin catabolic pathways. We measured the relevant physiological indicators and found that the content of soluble sugar and α-amylase activity increased, but the pectin content decreased. These findings establish a theoretical foundation for applying GA<sub>4+7</sub> in the standardized production of <i>P. cyrtonema</i>, particularly for accelerating breeding cycles in medicinal germplasm development.
ISSN:2311-7524