School of Horticulture and Plant Protection, Yangzhou University, Yangzhou, Jiangsu, P. R. China.
Key Laboratory of Plant Stress Biology, School of Life Sciences, Henan University, Kaifeng, 475004, China.
BMC Genomics. 2020 Oct 12;21(1):707. doi: 10.1186/s12864-020-07098-5.
Lotus is an aquatic horticultural crop that is widely cultivated in most regions of China and is used as an important off-season vegetable. The principal root of lotus is degenerated, and adventitious roots (ARs) are irreplaceable for plant growth. We found that no ARs formed under darkness and that exposure to high-intensity light significantly promoted the development of root primordia. Four differential expression libraries based on three light intensities were constructed to monitor metabolic changes, especially in indole-3-acetic acid (IAA) and sugar metabolism.
AR formation was significantly affected by light, and high light intensity accelerated AR development. Metabolic changes during AR formation under different light intensities were evaluated using gene expression profiling by high-throughput tag-sequencing. More than 2.2 × 10 genes were obtained in each library; the expression level of most genes was between 0.01 and 100 (FPKF value). Libraries constructed from plants grown under darkness (D/CK), under 5000 lx (E/CK), and under 20,000 lx (F/CK) contained 1739, 1683, and 1462 upregulated genes and 1533, 995, and 834 downregulated genes, respectively, when compared to those in the initial state (CK). Additionally, we found that 1454 and 478 genes had altered expression in a comparison of libraries D/CK and F/CK. Gene transcription between libraries D/F ranged from a 5-fold decrease to a 5-fold increase. Twenty differentially expressed genes (DEGs) were involved in the signal transduction pathway, 28 DEGs were related to the IAA response, and 35 DEGs were involved in sugar metabolism. We observed that the IAA content was enhanced after seed germination, even in darkness; this was responsible for AR formation. We also observed that sucrose could eliminate the negative effect of 150 μMol IAA during AR development.
AR formation was regulated by IAA, even in the dark, where induction and developmental processes could also be completed. In addition, 36 genes displayed altered expression in carbohydrate metabolism and ucrose metabolism was involved in AR development (expressed stage) according to gene expression and content change characteristics.
荷花是一种水生园艺作物，在中国大部分地区广泛种植，是淡季蔬菜的重要来源。荷花的主根退化，不定根（ARs）是植物生长不可或缺的。我们发现，在黑暗中不会形成不定根，而高强度光照会显著促进根原基的发育。基于三种光强度构建了四个差异表达文库，以监测代谢变化，特别是吲哚-3-乙酸（IAA）和糖代谢。
光照显著影响不定根的形成，高强度光照加速了不定根的发育。通过高通量标签测序的基因表达谱评估不同光照强度下不定根形成过程中的代谢变化。每个文库获得超过 2.2×10个基因；大多数基因的表达水平在 0.01 到 100 之间（FPKF 值）。在黑暗（D/CK）、5000 lx（E/CK）和 20000 lx（F/CK）下生长的植物构建的文库与初始状态（CK）相比，分别包含 1739、1683 和 1462 个上调基因和 1533、995 和 834 个下调基因。此外，我们发现 D/CK 和 F/CK 之间的文库比较中有 1454 和 478 个基因表达发生改变。文库 D/F 之间的基因转录从 5 倍下降到 5 倍增加。20 个差异表达基因（DEGs）参与信号转导途径，28 个 DEGs 与 IAA 反应有关，35 个 DEGs 参与糖代谢。我们观察到，即使在黑暗中，种子发芽后 IAA 含量也会增加，这是不定根形成的原因。我们还观察到，蔗糖可以消除 150μMol IAA 在不定根发育过程中的负面影响。
即使在黑暗中，IAA 也能调节不定根的形成，诱导和发育过程也能完成。此外，根据基因表达和含量变化特征，有 36 个基因在碳水化合物代谢中表达发生改变，蔗糖参与不定根发育（表达阶段）。
