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Updated: Jun 29, 2025
MALDI-Mass Spectrometric Imaging for the Investigation of Metabolites in Medicago truncatula Root Nodules
Published on: March 5, 2014
Unveiling the regulatory mechanisms of nodules development and quality formation in Panax notoginseng using
Muyao Yu1, Chunxia Ma2, Badalahu Tai3
1State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China; School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 102488, China.
Introduction:
Renowned for its role in traditional Chinese medicine, Panax notoginseng exhibits healing properties including bidirectional regulatory effects on hematological system diseases. However, the presence of nodular structures near the top of the main root, known as nail heads, may impact the quality of the plant's valuable roots.
Objectives:
In this paper, we aim to systematically analyze nail heads to identify their potential correlation with P. notoginseng quality. Additionally, we will investigate the molecular mechanisms behind nail head development.
Methods:
Morphological characteristics and anatomical features were analyzed to determine the biological properties of nail heads. Active component analysis and MALDI mass spectrometry imaging (MALDI-MSI) were performed to determine the correlation between nail heads and P. notoginseng quality. Phytohormone quantitation, MALDI-MSI, RNA-seq, and Arabidopsis transformation were conducted to elucidate the mechanisms of nail head formation. Finally, protein-nucleic acid and protein-protein interactions were investigated to construct a transcriptional regulatory network of nodule development and quality formation.
Results:
Our analyses have revealed that nail heads originate from an undeveloped lateral root. The content of ginsenosides was found to be positively associated with the amount of nail heads. Ginsenoside Rb1 specifically accumulated in the cortex of nail heads, while IAA, tZR and JAs also showed highest accumulation in the nodule. RNA-seq analysis identified PnIAA14 and PnCYP735A1 as inhibitors of lateral root development. PnMYB31 and PnMYB78 were found to form binary complexes with PnbHLH31 to synergistically regulate the expression of PnIAA14, PnCYP735A1, PnSS, and PnFPS.
Conclusion:
Our study details the major biological properties of nodular structures in P. notoginseng and outlines their impact on the quality of the herb. It was also determined that PnMYB31- and PnMYB78-PnbHLH31 regulate phytohormones and ginsenosides accumulation, further affecting plant development and quality. This research provides insights for quality evaluation and clinical applications of P. notoginseng.
