Work

Hetero-grafting affects sugar and flavonoid accumulation in ‘Misty’ blueberry (Vaccinium corymbosum)

Year: 2026

Type: article

Abstract: Introduction Grafting can be used in blueberry cultivation to improve soil adaptability and scion fruit quality. However, the underlying molecular mechanisms remain poorly understood. Methods We investigated the effects of rabbiteye blueberry ( Vaccinium virgatum ) ‘Climax’ and ‘Brightwell’ rootstocks on fruit quality, biochemical characteristics, and related gene expression in ‘Misty’ blueberry ( Vaccinium corymbosum ). Results The fruit quality of ‘Climax’-grafted ‘Misty’ (CM) was superior to that of ‘Brightwell’-grafted ‘Misty’ (BM). CM showed greater scion stem diameter and fruit size, as well as the net photosynthetic rate, and chlorophyll contents in leaves. Notably, LC-MS/MS analysis detected significant increases in specific sugars and flavonoids in CM fruit, with glucose and fructose contents 10.2% and 11.4% higher than BM, respectively. Twenty-four out of the 31 quantified flavonoids were more abundant in CM. In contrast, 26 of the 28 detected amino acids accumulated at higher levels in BM, as did most organic acids. A total of 1,411 differentially expressed genes, including 830 upregulated and 581 downregulated genes, were detected between CM and BM fruit, in which the genes associated with sugar ( VcSWEET12 and VcINV1 ) and flavonoids ( VcF3′H and VcUFGT ) were upregulated in CM fruit. An integrated analysis pinpointed nine transcription factors, including VcWRKY75 and VcWRKY24 , as potential modulators of sugar metabolism and flavonoid biosynthesis. Discussion These findings indicate that different rabbiteye blueberry rootstocks are associated with distinct physiological and metabolic responses in southern highbush blueberry. Compared with ‘Brightwell’, the ‘Climax’ rootstock was more conducive to improving the comprehensive quality of ‘Misty’ blueberry fruit. The results provide candidate molecular targets for dissecting the process of fruit quality formation mediated by rootstock–scion interactions, and they form a basis for high-quality blueberry cultivation.

Source: Frontiers in Plant Science

DOI: 10.3389/fpls.2026.1995904