Li Lujia, Wang Yucheng, Liu Wenhui, Gao Yue, Wang Jiawen, Lu Huifang, Xu Weiman, Wang Qin-Mei
Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, College of Forestry, Shenyang Agricultural University, Shenyang, 110866, China.
BMC Plant Biol. 2025 Jul 2;25(1):825. doi: 10.1186/s12870-025-06835-w.
Lycium ruthenicum is an economically important shrub known for its resistance to drought and saline-alkali conditions. This study identified a particular L. ruthenicum clone whose leaf explants can undergo direct organogenesis on plant growth regulator (PGR)-free media, and both rooting and shooting abilities of the leaf-tip explants were significantly greater than those of the leaf-middle explants. However, the underlying mechanisms remain unclear.
RNA-Seq analysis revealed that the differentially expressed genes (DEGs) associated with rooting and shooting in both leaf-tip and leaf-middle explants were enriched in the Plant hormone signal transduction KEGG pathway. For the first time, we identified 16 and nine differentially accumulated metabolites (DAMs) linked to direct root and shoot organogenesis from leaf explants, respectively. The stronger direct rooting ability observed in leaf-tip explants was associated with (i) up-regulation of sucrose synthase (SUS), scarecrow-like 21 (SCL21), transport inhibitor response 1 (TIR1), and auxin response factor (ARF) genes; (ii) up-regulation of IAA, IAA-Leu-Me, and BAP; (iii) down-regulation of eight DAMs. Moreover, the enhanced direct shooting ability in leaf-tip explants was correlated with (i) 13 DAMs including upregulated JA and JA-ILE, (ii) up-regulated SUS and (iii) down-regulated jasmonate ZIM domain 2 (JAZ2) gene. Notably, JAZ2 and these 13 DAMs represent newly discovered factors associated with the stronger shooting ability of leaf explants. Additionally, this study conducted correlation analyses between DAMs and DEGs related to rooting and shooting in leaf explants, as well as the enhanced rooting and shooting capacities of leaf-tip explants.
This study identifies the key DEGs and DAMs correlated with the direct organogenesis of L. ruthenicum leaf explants. Building upon these findings, a mechanistic model for the stronger direct organogenesis observed in leaf-tip explants was established. These findings offer valuable theoretical guidance for optimizing direct organogenesis systems in plant leaves.
黑果枸杞是一种具有重要经济价值的灌木，以其耐旱和耐盐碱特性而闻名。本研究鉴定出一个特定的黑果枸杞克隆，其叶片外植体能够在无植物生长调节剂（PGR）的培养基上直接进行器官发生，并且叶尖外植体的生根和发芽能力显著高于叶中部分外植体。然而，其潜在机制仍不清楚。
RNA测序分析表明，叶尖和叶中部分外植体中与生根和发芽相关的差异表达基因（DEGs）在植物激素信号转导KEGG途径中富集。我们首次分别鉴定出16种和9种与叶片外植体直接根和芽器官发生相关的差异积累代谢物（DAMs）。在叶尖外植体中观察到的较强直接生根能力与以下因素有关：（i）蔗糖合酶（SUS）、稻草人样21（SCL21）、运输抑制剂响应1（TIR1）和生长素响应因子（ARF）基因的上调；（ii）IAA、IAA-Leu-Me和BAP的上调；（iii）8种DAMs的下调。此外，叶尖外植体中增强的直接发芽能力与以下因素相关：（i）包括上调的茉莉酸（JA）和茉莉酸异亮氨酸（JA-ILE）在内的13种DAMs；（ii）SUS的上调；（iii）茉莉酸ZIM结构域2（JAZ2）基因的下调。值得注意的是，JAZ2和这13种DAMs代表了与叶片外植体更强发芽能力相关的新发现因素。此外，本研究还对叶片外植体中与生根和发芽相关的DAMs和DEGs之间以及叶尖外植体增强的生根和发芽能力进行了相关性分析。
本研究确定了与黑果枸杞叶片外植体直接器官发生相关的关键DEGs和DAMs。基于这些发现，建立了叶尖外植体中观察到的更强直接器官发生的机制模型。这些发现为优化植物叶片直接器官发生系统提供了有价值的理论指导。
