Effects of Exogenous 24-Epibrassinolide Leaves Spraying Application on Chlorophyll Accumulation and Gene Expression Profiles of Chlorophyll Metabolism in Celery
Chen Chen,
Li-Xiang Wang,
Meng-Yao Li,
Guo-Fei Tan,
Er-Jin Zhang,
Pei-Zhuo Liu,
Hui Liu,
Jian-Ping Tao,
Sheng Shu,
Jian-Hua Zhou,
Ai-Sheng Xiong
Affiliations
Chen Chen
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Ministry of Agriculture and Rural Affairs Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
Li-Xiang Wang
Suqian Facility Horticulture Research Institute of Nanjing Agricultural University, Suqian 223800, China
Meng-Yao Li
College of Horticulture, Sichuan Agricultural University, Chengdu 611130, China
Guo-Fei Tan
Institute of Horticulture, Guizhou Academy of Agricultural Sciences, Guiyang 550006, China
Er-Jin Zhang
College of Biology and Biotechnology, Yangzhou University, Yangzhou 225009, China
Pei-Zhuo Liu
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Ministry of Agriculture and Rural Affairs Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
Hui Liu
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Ministry of Agriculture and Rural Affairs Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
Jian-Ping Tao
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Ministry of Agriculture and Rural Affairs Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
Sheng Shu
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Ministry of Agriculture and Rural Affairs Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
Jian-Hua Zhou
Zhengzhou Vegetable Institute, Zhengzhou 450015, China
Ai-Sheng Xiong
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Ministry of Agriculture and Rural Affairs Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
Celery is an important leaf vegetable crop in Apiaceae, of which the petiole and leaf blade are the main edible parts. The content and proportion of photosynthetic pigments, mainly chlorophyll, have an important effect on the growth and quality of celery. As a brassinosteroid (BR) plant hormone with high physiological activity, 24-epibrassinolide (24-EBL) has the physiological functions of promoting chlorophyll accumulation and delaying leaf senescence. To investigate the effects of 24-EBL treatment on chlorophyll accumulation at different growth stages of celery, celery plants (variety Ningqin NO. 1) were treated from 45~59 days after sowing (DAS), at intervals of 7 days, with two different concentrations of 24-EBL: 1.04 × 10−6 mol·L−1 and 1.67 × 10−6 mol·L−1. The content of chlorophyll and the expression levels of genes related to its metabolism were determined in celery leaf blades and petioles at three different stages (52, 59, 66 DAS). In the first stage (52 DAS), 1.04 × 10−6 mol·L−1 treatment of 24-EBL increased the expression levels of genes related to chlorophyll biosynthesis (AgHEML, AgCHLG, and AgCAO) to promote the accumulation of chlorophyll in leaf blades. During the second and third stages (59 and 66 DAS, respectively), 1.67 × 10−6 mol·L−1 24-EBL treatment induced the expression levels of genes related to chlorophyll cyclic regeneration (AgCLH) and inhibited the up-regulation of genes related to chlorophyll degradation (AgNYC, AgHCAR, and AgPPH) to promote chlorophyll (especially chlorophyll b) accumulation. These treatments regulated the ratio of chlorophyll a content to chlorophyll b content and changed the leaf color of the celery. The results show that leaf spraying with an appropriate concentration of 24-EBL can facilitate chlorophyll synthesis by promoting chlorophyll synthesis and cycling-related gene expression levels and increase chlorophyll content in the leaves of celery. This study provides a reference for exploring the specific function of 24-EBL in regulating chlorophyll content during the growth and development of celery.
