Wang Cimei, Yang Yingying, Yu Jieting, Liu Zongli, Wei Wei, Chen Jianye, Zhu Jianhua, Huang Riming
Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China.
Guangdong Provincial Key Laboratory of Utilization and Conservation of Food and Medicinal Resources in Northern Region, School of Food Sciences and Engineering, Shaoguan University, Shaoguan 512005, China.
Foods. 2024 May 22;13(11):1607. doi: 10.3390/foods13111607.
6-BA, a small molecule compound of cytokinins, has been proven to delay leaf senescence in different species, including Chinese flowering cabbage; however, its specific mechanism remains relatively unknown. In this study, the application of external 6-BA delayed leaf senescence in Chinese flowering cabbage, showing that 6-BA effectively prevented the decrease in the maximum quantum yield (Fv/Fm) and overall chlorophyll content and suppressed the expression of the senescence-associated gene over a 7-day period of storage. Moreover, treatment with 6-BA decreased the respiratory rate, NAD(H) content, the activities of hexose phosphate isomerase (PHI), succinate dehydrogenase (SDH), cytochrome c oxidase (CCO), and ascorbic acid oxidase (AAO) using enzyme-linked immunosorbent assay, and the transcriptional abundance of related genes by real-time quantitative polymerase chain reaction. Furthermore, 6-BA also increased the activity and expression levels of glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphate gluconate dehydrogenase (6-PGDH). The group treated with 6-BA retained elevated levels of NADP (H), ATP, total ATPase, and nicotinamide adenine dinucleotide kinase (NADK) activity, as well as the expression of respiratory enzymes. Molecular docking indicated that 6-BA hinders the glycolysis pathway (EMP), tricarboxylic acid cycle (TCA), and cytochrome pathway (CCP), and sustains elevated levels of the pentose phosphate pathway (PPP) through interactions with the PHI, SDH, 6-PGDH, G6PDH, CCO, and AAO proteins, consequently delaying postharvest leaf senescence in Chinese flowering cabbage.
6-苄氨基腺嘌呤（6-BA）是一种细胞分裂素小分子化合物，已被证明能延缓包括菜心在内的不同物种叶片衰老；然而，其具体机制仍相对不明。在本研究中，外源施加6-BA延缓了菜心叶片衰老，表明6-BA有效防止了最大量子产量（Fv/Fm）和总叶绿素含量的下降，并在7天的贮藏期内抑制了衰老相关基因的表达。此外，通过酶联免疫吸附测定，6-BA处理降低了呼吸速率、NAD(H)含量、磷酸己糖异构酶（PHI）、琥珀酸脱氢酶（SDH）、细胞色素c氧化酶（CCO）和抗坏血酸氧化酶（AAO）的活性，通过实时定量聚合酶链反应降低了相关基因的转录丰度。此外，6-BA还提高了葡萄糖-6-磷酸脱氢酶（G6PDH）和6-磷酸葡萄糖酸脱氢酶（6-PGDH）的活性和表达水平。用6-BA处理的组保持了较高水平的NADP(H)、ATP、总ATP酶和烟酰胺腺嘌呤二核苷酸激酶（NADK）活性以及呼吸酶的表达。分子对接表明，6-BA通过与PHI、SDH、6-PGDH、G6PDH、CCO和AAO蛋白相互作用，阻碍糖酵解途径（EMP）、三羧酸循环（TCA）和细胞色素途径（CCP），维持戊糖磷酸途径（PPP）的高水平，从而延缓菜心采后叶片衰老。
