Effects of Vacuum Packaging on Enzymatic Browning and Ethylene Response Factor (ERF) Gene Expression of Fresh-cut Lotus Root

Abstract

Ethylene response factor (ERF) genes have been involved in responses to biotic and abiotic stress, including hypoxia and anaerobic stress. Vacuum packaging (a typical anaerobic stress) is an effective storage method used to delay browning of fresh-cut lotus root (Nelumbo nucifera). In model plants, ERF genes have been identified as responsive to hypoxia. Whether ERF is associated with browning of vacuum-packaged lotus root has not been studied. The effects of vacuum packaging on browning, phenolic content, the enzyme activity of phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD), and PPO, PAL, POD, and ERF genes expression in fresh-cut lotus root were studied. Downregulation of NnPAL1, NnPPOA, and NnPOD2/3 attributable to vacuum packaging coincided with increased related enzyme activities and the degree of browning of fresh-cut lotus root. The expression patterns of NnERF4/5 were consistent with the changes in NnPAL1, NnPPOA, and NnPOD2/3 gene expression. It has been proposed that NnERF4/5 could have be important regulators of fresh-cut lotus root browning, and that the relationships of NnERF4/5 and NnPAL1, NnPPOA, and NnPOD2/3 should to be studied further.

Effects of Vacuum Packaging on NAC Gene Expression in Fresh-cut Lotus Root

“…By determining the BD in storage after using two different packaging methods, it was clear that the BD of the samples subjected to VP (anaerobic stress) was significantly less than that of the control group. These results confirmed and extended our previous finding (Min et al, 2019).…”

“…Changes in PAL, PPO, and POD enzymatic activity in storage under two different packaging methods were analyzed. These results showed that PAL, PPO, and POD activity were inhibited during VP, which occurred in parallel with less significant browning during storage, which was consistent with previous reports (Min et al, 2019), NNPAL, NNPPO, AND NNPOD GENE EXPRESSION. There was an obvious differential response to different packaging methods for the two PAL, two PPO, and seven POD genes.…”

“…In addition, changes in the expressions of NnPAL1, NnPPOA, and NnPOD2/3 were consistent with PAL, PPO, and POD enzyme activity changes. Previous studies and the current results further prove that NnPAL1, NnPPOA, and NnPOD2/3 may be important candidates for genes to target to control fresh-cut lotus root browning (Min et al, 2017(Min et al, , 2018(Min et al, , 2019.…”

“…Artificial treatments have been developed successfully to delay the browning of fresh-cut lotus roots, including modifiedatmosphere packaging (MAP) (Cheng et al, 2015), VP in lowtemperature storage (Min et al, 2017(Min et al, , 2019Xie et al, 2018), heat treatment (Tsouvaltzis et al, 2011), and so on. Among the various treatments, VP in low-temperature storage has been most successful in maintaining quality and prolonging the shelf life of fresh-cut lotus root (Aquino-Bolanos et al, 2000;Sharma and Rao, 2017;Toivonen and Brummell, 2008).…”

“…Total phenolic content, oxygen, PPO, and POD are known to be the main factors that cause browning (Du et al, 2009;Walker and Ferrar, 1998). Our previous research reported that NnPAL1, NnPPOA, and NnPOD2/3 are the most promising candidates for genes to target to control fresh-cut lotus root browning with MAP and VP in low-temperature storage (Min et al, 2017(Min et al, , 2018(Min et al, , 2019.…”