Evolutionary analysis and role of invertase inhibitors in regulating
sucrose metabolism in peach fruit under chilling stress
Sucrose metabolism, particularly the decomposition of sucrose by
invertase, plays a central role in plants’ response to cold stress.
Invertases inhibitors (INHs) evolved with higher plants as essential
regulators of sucrose metabolism. By limiting invertase activity, INHs
keep cellular sugar levels elevated, which provides enhanced protection
for plants under stress. As the only vacuolar invertase (VIN) gene in
peaches sensitive to chilling temperatures, our results showed that
PpVIN2 expression increases significantly during cold storage, while VIN
activity increases more modestly. We also found that peaches transiently
overexpressing PpINH1 had decreased VIN activity. The interaction of
PpINH1 and PpVIN2 was shown by yeast two-hybrid, bimolecular
fluorescence complementation, and in vitro, with recombinant proteins.
During cold storage, trehalose treated peaches had significantly
increased PpINH1 expression, decreased VIN activity, and significantly
higher sucrose content than untreated fruit. As a result, treated fruit
had enhanced resistance to chilling injury. Collectively, our data show
that the post-translational repression of VIN activity by PpINH1 helps
maintain sucrose levels in peaches during cold storage, thereby
improving resistance to chilling injury.