SlNAC1 mediates MeSA application-promoted cold resistance by improving transcription of SlNRX2 in tomato fruit

Abstract

Refrigeration process is often regarded as a traditional practice utilized to conserve nutritive value in postharvest horticultural products. As a result of susceptibility to low temperature environment, tomato fruit exhibit the development of chilling injury (CI) during refrigerated preservation, ultimately constraining marketability. Methyl salicylate (MeSA) application attenuated the CI in tomatoes. The MeSA-dipped fruit possessed the compromised reactive oxygen species (ROS) generation. MeSA application was conducive to improve the transcription level of SlNAC1. The SlNAC1-OE fruit displayed the increase in cold resistance, accompanied by the diminished amount of ROS. In contrast, the lower cold resistance and larger amount of ROS were observed in the SlNAC1-silenced fruit. MeSA application conferred the boosted transcription level of nucleoredoxin 2 (SlNRX2). Moreover, the transcription abundances of SlNRX2 increased by overexpression of SlNAC1, but decreased by RNAi of SlNAC1. It was substantiated that SlNAC1 transcriptionally promoted the SlNRX2 expression by targeting the NAC binding motif in its promoter region afterwards. Collectively, SlNAC1 was involved in the MeSA application-weakened sensitivity to low temperature stress by transactivating SlNRX2 in tomato fruit.