College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
Int J Mol Sci. 2023 Feb 2;24(3):2933. doi: 10.3390/ijms24032933.
Flowering Chinese cabbage is prone to withering, yellowing and deterioration after harvest. Melatonin plays a remarkable role in delaying leaf senescence and increasing flavonoid biosynthesis. However, the underlying molecular mechanisms of melatonin procrastinating postharvest senescence by regulating flavonoid biosynthesis remain largely unknown. In this study, melatonin could promote flavonoid accumulation and delay the postharvest senescence of flowering Chinese cabbage. Surprisingly, we observed that and were core contributors in flavonoid biosynthesis, and BrERF2 and BrERF109 were crucial ethylene response factors (ERFs) through the virus-induced gene silencing (VIGS) technique, which is involved in regulating the postharvest senescence under melatonin treatment. Furthermore, yeast one-hybrid (Y1H), dual luciferase (LUC), and β-glucuronidase (GUS) tissue staining experiments demonstrated that BrERF2/BrERF109 negatively regulated the transcripts of and by directly binding to their promoters, respectively. Silencing significantly upregulated the transcripts of and , promoting flavonoid accumulation, and postponing the leaf senescence. Our results provided a new insight into the molecular regulatory network of melatonin delaying leaf senescence and initially ascertained that melatonin promoted flavonoid accumulation by suppressing the inhibition of BrERF2/BrERF109 on the transcripts of and , which led to delaying the leaf senescence of postharvest flowering Chinese cabbage.
菜花在收获后容易枯萎、发黄和变质。褪黑素在延缓叶片衰老和增加类黄酮生物合成方面起着显著的作用。然而，褪黑素通过调节类黄酮生物合成来延缓采后衰老的潜在分子机制在很大程度上仍然未知。在本研究中，褪黑素可以促进类黄酮的积累并延缓菜花的采后衰老。令人惊讶的是，我们观察到和是类黄酮生物合成的核心贡献者，通过病毒诱导的基因沉默（VIGS）技术，BrERF2 和 BrERF109 是关键的乙烯响应因子（ERFs），它们参与了褪黑素处理下的采后衰老调控。此外，酵母单杂交（Y1H）、双荧光素酶（LUC）和β-葡萄糖醛酸酶（GUS）组织染色实验表明，BrERF2/BrERF109 通过直接结合它们的启动子，分别负调控和的转录本。沉默显著地上调了和的转录本，促进了类黄酮的积累，并推迟了叶片衰老。我们的结果为褪黑素延缓叶片衰老的分子调控网络提供了新的见解，并初步确定褪黑素通过抑制 BrERF2/BrERF109 对和的转录本的抑制作用来促进类黄酮的积累，从而延缓了采后菜花的叶片衰老。
