Silencing of Sly-miR160a enhanced postharvest chilling tolerance of tomato fruit

Abstract

Tomato fruit is usually stored at low temperature to maintain quality and extend shelf life, but it is sensitive to cold conditions and prone to chilling injury (CI) symptoms. In this study, the effect of Sly-miR160a on the postharvest cold tolerance of tomato fruit was investigated. The results showed that silencing of miR160a by a short tandem target mimic (miR160a-STTM) resulted in a decrease in fruit CI index and weight loss and an increase in fruit firmness compared with wild-type (WT) and tomato fruit overexpressing Sly-miR160a (miR160a-OE). Additionally, the levels of hydrogen peroxide (H₂O₂), superoxide anion (O₂^•−), malondialdehyde (MDA), and electrolyte leakage (EL) in the fruit of miR160a-STTM decreased, while the content of total phenol increased. At low temperature, silencing of miR160a increased the expression of WRKY33 by up-regulating the target gene ARF17 in response to chilling injury stress. Meanwhile, miR160a-STTM fruit had higher ABA content and higher expression of cold-responsive genes such as ICE1a, CBF1, and COR. These findings suggest that the silencing of Sly-miR160a enhanced the postharvest cold tolerance of tomato fruit by reducing reactive oxygen species (ROS) accumulation, enhancing antioxidant capacity, ABA signaling pathway, and ICE1-CBF1-COR cold signaling pathway.