Hainan Key Laboratory of Tropical Oil Crops Biology, Coconut Research Institute, Chinese Academy of Tropical Agricultural Sciences, Wenchang 571339, China.
Institute of Scientific and Technical Information, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
Int J Mol Sci. 2024 Oct 14;25(20):11021. doi: 10.3390/ijms252011021.
is one of the camellia plants distributed in tropical regions, and its regeneration system and genetic transformation are affected by callus browning. However, the underlying mechanism of callus browning formation remains largely unknown. To investigate the metabolic basis and molecular mechanism of the callus browning of , histological staining, high-throughput metabolomics, and transcriptomic assays were performed on calli with different browning degrees (T1, T2, and T3). The results of histological staining revealed that the brown callus cells had obvious lignification and accumulation of polyphenols. Widely targeted metabolomics revealed 1190 differentially accumulated metabolites (DAMs), with 53 DAMs annotated as phenylpropanoids and flavonoids. Comparative transcriptomics revealed differentially expressed genes (DEGs) of the T2 vs. T1 associated with the biosynthesis and regulation of flavonoids and transcription factors in . Among them, forty-four enzyme genes associated with flavonoid biosynthesis were identified, including (), (), via (), (), (), (), (), (), (), (), and (). Related transcription factors , (), and genes also presented different expression patterns in T2 vs. T1. These results indicate that the browning of calli in is regulated at both the transcriptional and metabolic levels. The oxidation of flavonoids and the regulation of related structural genes and transcription factors are crucial decisive factors. This study preliminarily revealed the molecular mechanism of the browning of the callus of Camellia hainanensis, and the results can provide a reference for the anti-browning culture of callus.
是一种分布在热带地区的山茶植物，其再生系统和遗传转化受到愈伤组织褐变的影响。然而，愈伤组织褐变形成的潜在机制在很大程度上仍然未知。为了研究 愈伤组织褐变的代谢基础和分子机制，对褐变程度不同的愈伤组织（T1、T2 和 T3）进行了组织学染色、高通量代谢组学和转录组学分析。组织学染色的结果表明，褐色愈伤组织细胞有明显的木质化和多酚积累。广泛靶向代谢组学揭示了 1190 个差异积累代谢物（DAMs），其中 53 个 DAMs 被注释为苯丙烷类和类黄酮。比较转录组学揭示了 T2 与 T1 相关的差异表达基因（DEGs）与类黄酮的生物合成和调节以及 中的转录因子有关。其中，鉴定了 44 个与类黄酮生物合成相关的酶基因，包括 （）、 （）、 （）通过 （）、 （）、 （）、 （）、 （）、 （）、 （）和 （）。相关转录因子 （）、 （）和 基因在 T2 与 T1 中的表达模式也不同。这些结果表明， 愈伤组织的褐变受转录和代谢水平的调节。类黄酮的氧化和相关结构基因和转录因子的调节是关键的决定性因素。本研究初步揭示了 愈伤组织褐变的分子机制，研究结果可为 愈伤组织的抗褐变培养提供参考。
