FOOD SCIENCE ›› 2021, Vol. 42 ›› Issue (17): 54-62.doi: 10.7506/spkx1002-6630-20210324-301

• Basic Research • Previous Articles     Next Articles

Changes in Abscisic Acid Accumulation and Gene Expression Involved in Abscisic Acid Metabolism in Mandarins (Citrus reticulata Blanco) after Peel Puffing

HE Mingyang, HONG Min, WANG Rikui, YU Zuixin, ZHU Li, ZHOU Lian, DENG Tujing   

  1. (1. Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, Chongqing 400712, China; 2. Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; 3. National Agro-Tech Extension Service Center, Beijing 100125, China)
  • Published:2021-09-29

Abstract: Abscisic acid (ABA) accumulates in citrus peel in quite high amounts after harvest. ABA biosynthesis is through the carotenoid metabolic pathway. In order to study the changes in ABA content and the expression levels of the genes involved in ABA metabolism in mandarins after peel puffing, puffed ‘Clementine’ and ‘ponkan’ fruits stored at 18–20 ℃ for 30 days and normal ones as a control group were used as research subjects in this study. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and quantitative real-time polymerase chain reaction (qPCR) were used to analyze ABA contents, carotenoid composition and gene expression levels involved in ABA metabolism in the peel. The results showed that after storage, peel puffing indexes in ‘Clementine’ and ‘Ponkan’ were increased by 177% and 186% respectively, and peel water contents were increased by 5.9% and 14.4%, respectively. ABA contents in the puffed peel of ‘Clementine’ and ‘Ponkan’ were 795.1 and 230.5 ng/g, respectively, significantly lower than those (1 659.2 and 464.6 ng/g) in the normal peel (P < 0.05). Pearson’s correlation analysis showed that ABA contents in the peel of puffed ‘Clementine’ and ‘Ponkan’ were significantly correlated with the content of β-carotene and the expression levels of LCYB1, LCYE and AB1 (P < 0.05). After peel puffing, the expression levels of LCYB1 and LCYE, both involved in ABA synthesis, were decreased and increased, respectively, inhibiting the synthesis of β-carotene and consequently ABA; AB1 expression level, involved in ABA decomposition, was significantly increased (P < 0.05), inhibiting ABA accumulation. Taken together, the decrease in ABA content after peel puffing is related to the down-regulation of β-carotene synthesis and the acceleration of ABA decomposition, co-regulated by LCYB1, LCYE and AB1. In addition, the occurrence of peel puffing in mandarins may result from relatively delayed senescence of the peel.

Key words: mandarins; peel puffing; abscisic acid; carotenoid; gene expression analysis

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