Nitric oxide delays the postharvest nutritional quality decline of “Golden Hook” beans

Abstract

Abstract“Golden Hook” beans turn purple to different degrees due to the different compositions and contents of flavonoids during storage. At the same time, quality losses due to softening or pathogen invasion, and the deteriorations of flavor associated with carbohydrate metabolism occur. To reveal the effect of nitric oxide (NO) generated from sodium nitroprusside (SNP) on the postharvest quality of “Golden Hook” beans, we used metabolome, transcriptome, and assay for transposase‐accessible chromatin with high‐throughput sequencing approaches to compare beans at the time of treatment with untreated and SNP‐treated beans stored at 8°C for 12 days. The results showed that NO induced the expression of CERK1, FLS2, JAZ, and MYC2, stimulated the expression of polyphenol oxidase, CAT, and l‐ascorbate oxidase, the accumulation of flavonoids, and the synthesis of lignin in the antioxidant system, improving the ability of beans to resist stress while maintaining the balance of reactive oxygen species. High expressions of F3′H, FLS, INV, SUS, BCAT, and the accumulation of 6‐C‐methylquercetin‐3‐O‐rutinoside were associated with the maintenance of the fresh purplish red appearance of the beans in the SNP‐12d group, without loss of flavor. SNP treatment downregulated the transcription factors blimp‐1, OBP1, COG1, and AT1G6957 associated with bean senescence. These results provide insight into the postharvest quality control of “Golden Hook” beans.