): [EMAIL_ADDRESS] (H.T.) Yunxiu Lin  
1 College of Horticulture, Sichuan Agricultural University, Chengdu 611130, China; [EMAIL_ADDRESS] (D.L. ): [EMAIL_ADDRESS] (Y.L. ): [EMAIL_ADDRESS] (B.Z. ); [EMAIL_ADDRESS] (H.T. ): [EMAIL_ADDRESS] (Y.Z. ): [EMAIL_ADDRESS] (Q.C. ); [EMAIL_ADDRESS] (Y.W. ): [EMAIL_ADDRESS] (M.L. ): [EMAIL_ADDRESS] (W.H. ); [EMAIL_ADDRESS] (Y.L. ): [EMAIL_ADDRESS] (X.W. ): [EMAIL_ADDRESS] (H.T.) Yunxiu Lin  
1 College of Horticulture, Sichuan Agricultural University, Chengdu 611130, China; [EMAIL_ADDRESS] (D.L. ): [EMAIL_ADDRESS] (Y.L. ): [EMAIL_ADDRESS] (B.Z. ); [EMAIL_ADDRESS] (H.T. ): [EMAIL_ADDRESS] (Y.Z. ): [EMAIL_ADDRESS] (Q.C. ); [EMAIL_ADDRESS] (Y.W. ): [EMAIL_ADDRESS] (M.L. ): [EMAIL_ADDRESS] (W.H. ); [EMAIL_ADDRESS] (Y.L. ): [EMAIL_ADDRESS] (X.W. ): [EMAIL_ADDRESS] (H.T.) Yunxiu Lin  
1 College of Horticulture, Sichuan Agricultural University, Chengdu 611130, China; [EMAIL_ADDRESS] (D.L. ): [EMAIL_ADDRESS] (Y.L. ): [EMAIL_ADDRESS] (B.Z. ); [EMAIL_ADDRESS] (H.T. ): [EMAIL_ADDRESS] (Y.Z. ): [EMAIL_ADDRESS] (Q.C. ); [EMAIL_ADDRESS] (Y.W. ): [EMAIL_ADDRESS] (M.L. ): [EMAIL_ADDRESS] (W.H. ); [EMAIL_ADDRESS] (Y.L. ): [EMAIL_ADDRESS] (X.W. ): [EMAIL_ADDRESS] (H.T. ):Ascorbic acid (AsA), also known as vitamin C, is an important antioxidant that has a variety of biological effects, such as photosynthesis, defense mechanisms, and cell division [6]. Although AsA is an indispensable substance for human beings, it is completely derived from dietary supplements [7]. More than 90% AsA is derived from fruits and vegetables; thus, ASA content acts as an important factor to evaluate fruit quality [8]. Therefore, it is particularly important to study the anabolism of AsA in plants. There are four ways proposed for the synthesis of AsA in plants, including the L-galactose pathway, the L-glucose pathway, the D-galacturonate pathway, and the myo-inositol pathway [9]. The L-galactose pathway consists of a series of successive reactions, starting from D-mannose-1-phosphate, GDP-L-galactose and L-galactone-1,4-lactone intermediate to the formation of AsA. In addition, AsA can be oxidized to monodehydroascorbate (MDHA) by ascorbate peroxidase (APX) and ascorbate oxidase (AO), then some MDHA can be further reduced by monodehydroascorbate reductase (MDHAR) to form AsA. On the other hand, MDHA can be disproportionated to dehydroascorbate (DHA) and AsA, and DHA can also be reduced to AsA by dehydroascorbate reductase (DHAR) [10]. At present, although there are in-depth studies on AsA and their regulatory mechanisms in fruit, the AsA biosynthetic pathway among different fruit species, developmental stages, and fruit organs is still unclear. Kiwifruit (_Actinidia_ Lindl.) is the most economically important of fruit trees and is favored by consumers owing to its high vitamin C content [11]. Many studies have shown that biosynthesis is the main cause of AsA accumulation in kiwifruit fruit, and the AsA content in fruit development is regulated by both synthesis and regeneration [12]. Moreover, there was a significant difference in the AsA content among different kiwifruit, and there was wide variation in AsA content in most cultivars of A. argute fruit; the AsA content was much higher than that of _A. deliciousa_ and _A. chinensis_[13]. For understanding the AsA accumulation among different genotypes, two different hardy kiwifruit cultivars were selected to perform changes in the AsA content and to reveal the molecular regulation of AsA accumulation in the fruit by transcriptome analysis. The results would be beneficial for kiwifruit breeding strategies, with the purpose of increasing AsA content.