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Article|21 Jul 2023|OPEN
A pear S1-bZIP transcription factor PpbZIP44 modulates carbohydrate metabolism, amino acid, and flavonoid accumulation in fruits 
Hong Wang1,2 , Kexin Xu1,2 , Xiaogang Li2 , Bárbara Blanco-Ulate3 , Qingsong Yang2 , Gaifang Yao4 , Yiduo Wei3 , Jun Wu1 , Baolong Sheng2 and Youhong Chang2 , Cai-Zhong Jiang3,5 , , Jing Lin,1,2 ,
1College of Horticulture, Nanjing Agricultural University, Nanjing 210014, China
2Institute of Pomology, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
3Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
4School of Food and Biological Engineering, Hefei University of Technology, Hefei 230009, China
5Crops Pathology and Genetics Research Unit, United States Department of Agriculture, Agricultural Research Service, Davis, California, 95616, USA
*Corresponding author. E-mail:,

Horticulture Research 10,
Article number: uhad140 (2023)
Views: 250

Received: 26 Mar 2023
Accepted: 08 Jul 2023
Published online: 21 Jul 2023


Fruit quality is defined by attributes that give value to a commodity. Flavor, texture, nutrition, and shelf life are key quality traits that ensure market value and consumer acceptance. In pear fruit, soluble sugars, organic acids, amino acids, and total flavonoids contribute to flavor and overall quality. Transcription factors (TFs) regulate the accumulation of these metabolites during development or in response to the environment. Here, we report a novel TF, PpbZIP44, as a positive regulator of primary and secondary metabolism in pear fruit. Analysis of the transient overexpression or RNAi-transformed pear fruits and stable transgenic tomato fruits under the control of the fruit-specific E8 promoter demonstrated that PpZIP44 substantially affected the contents of soluble sugar, organic acids, amino acids, and flavonoids. In E8::PpbZIP44 tomato fruit, genes involved in carbohydrate metabolism, amino acid, and flavonoids biosynthesis were significantly induced. Furthermore, in PpbZIP44 overexpression or antisense pear fruits, the expression of genes in the related pathways was significantly impacted. PpbZIP44 directly interacted with the promoter of PpSDH9 and PpProDH1 to induce their expression, thereby depleting sorbitol and proline, decreasing citrate and malate, and enhancing fructose contents. PpbZIP44 also directly bound to the PpADT and PpF3H promoters, which led to the carbon flux toward phenylalanine metabolites and enhanced phenylalanine and flavonoid contents. These findings demonstrate that PpbZIP44 mediates multimetabolism reprogramming by regulating the gene expression related to fruit quality compounds.