Auto- and mutual-regulation between two CitERFs contribute to ethylene-induced citrus fruit degreening

• Published in: Food chemistry Vol. 299; p. 125163
• Main Authors: Li, Shao-jia, Xie, Xiu-lan, Liu, Sheng-chao, Chen, Kun-song, Yin, Xue-ren
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 30.11.2019
• Subjects: Auto- and mutual-regulation; Chlorophyll - genetics; Chlorophyll - metabolism; Chlorophyll degradation; Citrus - physiology; Citrus fruit; Degreening; Ethylene; Ethylene response factor; Ethylenes - metabolism; Food Storage; Fruit - physiology; Gene Expression Regulation, Plant; Nicotiana - genetics; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified; Promoter Regions, Genetic; Auto- and mutual-regulation; Ethylene response factor; Degreening; Chlorophyll degradation; Citrus fruit; Ethylene
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2019.125163

•CitERF6 was identified as a novel positive regulator on chlorophyll degradation.•Auto- and mutual-regulation was found between CitERF6 and CitERF13.•Auto- and mutual-regulation facilitate the effect of ethylene, leading to fruit degreening. Citrus fruit postharvest degreening is a critical stage in marketing, carried out by exposure to ethylene or ethephon. Genome-wide screening of the AP2/ERF superfamily indicated that a novel ERF-II (CitERF6) was shown to trans-activate the CitPPH promoter. Expression of CitERF6 is associated with both developmental and postharvest degreening in citrus fruit. Transient and stable over-expression of CitERF6 in Nicotiana tabacum leaves and ‘Ponkan’ fruit also results in rapid chlorophyll degradation. Auto- and mutual-regulation was also found between CitERF6 and the previously characterized CitERF13 using the dual-luciferase and yeast one-hybrid assays. Moreover, substitution of the 35S promoter for endogenous promoters showed that both pCitERF6::CitERF6 and pCitERF13::CitERF13 were effective in trans-activating their promoters or triggering chlorophyll degradation. It is proposed that ethylene is one of the triggers activating promoters of CitERF6 and CitERF13, and subsequent auto- and mutual-regulation between CitERF6 and CitERF13 might facilitate the effect of ethylene, leading to fruit degreening.