NaHCO3 accelerates the aging of tobacco leaves; however, the underlying molecular mechanisms have not been elucidated. This study aimed to explore the mechanism of NaHCO3 in the promotion of tobacco leaf maturation using transcriptome analysis. Leaves on plants or detached leaves of the tobacco variety, Honghua Dajinyuan, were sprayed with or without 1% NaHCO3. The leaf yellowing was observed, the pigment content and enzyme activities were determined and RNA sequencing (RNA-seq) was performed. Spraying NaHCO3 onto detached leaves was found to promote leaf yellowing. Pigment content, catalase activity, and superoxide dismutase activity significantly decreased, whereas peroxidase activity and malondialdehyde content significantly increased. RNA-seq demonstrated that spraying with NaHCO3 upregulated genes associated with cysteine and methionine metabolism; alpha-linolenic acid metabolism; and phenylalanine, tyrosine, and tryptophan biosynthesis and downregulated genes related to photosynthesis and carotenoid biosynthesis. Genes correlated with autophagy-other, valine, leucine, and isoleucine degradation, and the MAPK signaling pathway were upregulated while those correlated with DNA replication, phenylalanine, and tyrosine and tryptophan biosynthesis were downregulated in detached leaves sprayed with NaHCO3 compared with the plant leaves sprayed with NaHCO3. Overall, this study is the first to elucidate the molecular and metabolic mechanisms of NaHCO3 in the promotion of tobacco leaf maturation.

中文翻译：

---

转录组分析揭示NaHCO3促进烟叶成熟的机制

碳酸氢钠3加速烟叶的老化；然而，潜在的分子机制尚未阐明。本研究旨在探讨NaHCO的作用机制3利用转录组分析促进烟叶成熟。红花大金元烟草品种的植株叶片或离体叶片喷施或不喷施 1% NaHCO33。观察叶片变黄情况，测定色素含量和酶活性，并进行RNA测序（RNA-seq）。喷洒NaHCO33发现在脱落的叶子上会促进叶子变黄。色素含量、过氧化氢酶活性和超氧化物歧化酶活性显着降低，而过氧化物酶活性和丙二醛含量显着升高。 RNA-seq 证明喷洒 NaHCO3上调与半胱氨酸和蛋氨酸代谢相关的基因； α-亚麻酸代谢；苯丙氨酸、酪氨酸和色氨酸生物合成以及与光合作用和类胡萝卜素生物合成相关的基因下调。在喷洒NaHCO3的离体叶片中，与自噬-其他、缬氨酸、亮氨酸和异亮氨酸降解以及MAPK信号通路相关的基因上调，而与DNA复制、苯丙氨酸、酪氨酸和色氨酸生物合成相关的基因下调3与喷洒NaHCO3的植物叶片相比3。总的来说，这项研究首次阐明了NaHCO3的分子和代谢机制3促进烟叶成熟。