State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Engineering Research Center of Southern Horticultural Products Preservation, Ministry of Education, College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
Department of Food Science, Shenyang Agricultural University, Shenyang 110866, China.
Food Res Int. 2022 Jul;157:111455. doi: 10.1016/j.foodres.2022.111455. Epub 2022 Jun 6.
The regulatory role of cytokinins (CTKs) in leaf senescence has been documented in different species, including Chinese flowering cabbage. However, its physiological and molecular basis relatively remains unknown. In this study, exogenous application of a CTK analogue 6-benzylaminopurine (6-BA) significantly retarded leaf senescence of Chinese flowering cabbage, with less chlorophyll degradation and lower accumulation of reactive oxygen species (ROS) and malondialdehyde compared with the control group. Meanwhile, higher levels of soluble sugars and proteins, flavonoids, cellulose, amino acids, total phenols, procanthocyanins, and vitamin C were retained in 6-BA-treated leaves. 6-BA treatment also prevented the decline in endogenous CTK content and the increase in ethylene, abscisic acid, and jasmonic acid contents. Moreover, the comparative transcriptome analysis revealed that a total of 21,895 differently expressed genes (DEGs) were identified from four comparisons of 6-BA treatment versus the control during senescence. Further analysis showed that most of the identified DEGs were enriched in ROS, respiratory metabolism, and phytohormone pathways, and a total of 50 classes of transcription factors that were possibly involved in modulating these DEGs were obtained. The transcriptional levels of 18 DEGs were verified by Quantitative real-time PCR (qRT-PCR), which confirmed the accuracy of the transcriptomic data. Overall, these findings and data provide a comprehensive view of physiological and molecular events concerning with the CTK-mediated leaf senescence and -maintained quality in economical leafy vegetables.
细胞分裂素（CTKs）在不同物种的叶片衰老中发挥着调控作用，包括白菜花。然而，其生理和分子基础相对来说仍不清楚。在本研究中，外源施用细胞分裂素类似物 6-苄基氨基嘌呤（6-BA）可显著延缓白菜花的叶片衰老，与对照组相比，叶绿素降解较少，活性氧（ROS）和丙二醛积累较低。同时，6-BA 处理叶片中保持了较高水平的可溶性糖和蛋白质、类黄酮、纤维素、氨基酸、总酚、原花青素和维生素 C。6-BA 处理还防止了内源 CTK 含量的下降以及乙烯、脱落酸和茉莉酸含量的增加。此外，比较转录组分析显示，在衰老过程中，6-BA 处理与对照相比的四个比较中共鉴定出 21895 个差异表达基因（DEGs）。进一步分析表明，大多数鉴定出的 DEGs 富集在 ROS、呼吸代谢和植物激素途径中，获得了可能参与调节这些 DEGs 的总共 50 类转录因子。通过定量实时 PCR（qRT-PCR）验证了 18 个 DEGs 的转录水平，这证实了转录组数据的准确性。总的来说，这些发现和数据提供了关于 CTK 介导的叶片衰老和经济叶菜类蔬菜质量保持的生理和分子事件的全面视图。
