Fluroxypyr—a potential surrogate of 2,4-dichlorophenoxyacetic acid for retarding calyx senescence in postharvest citrus fruit

• 27 analogues of 2,4-d were selected from chemical databases by virtual screening.
• Fruits treated with fluroxypyr showed lower rates of calyx senescence and fruit decay.
• Fluroxypyr has no effect on fruit internal quality, firmness and color values.
• Fluroxypyr might be safer than the 2,4-d as a postharvest preservative of citrus fruit quality.

Searching for an effective and safer alternative to the citrus fruit preservative 2,4-dichlorophenoxyacetic acid (2,4-d) is an issue of common concern in citrus-producing countries. In this study, 27 structural and functional analogues of 2,4-d were preliminarily selected from ZINC database by computer virtual screening. Four varieties of fresh citrus fruits harvested from three consecutive mature seasons were applied in experimental tests, aiming to precisely evaluate the preservation effects of the selected analogues by a comprehensive comparison with the corresponding indices of 2,4-d. The results indicated that fluroxypyr, which has lower toxicity than 2,4-d, significantly reduced calyx senescence and fruit decay without affecting the internal quality of the fruit. Therefore, it can be speculated that fluroxypyr can be an effective and safer alternative to 2,4-d for the preservation of citrus fruits in storage.