Exogenous arginine enhances the chilling tolerance in postharvest papaya fruit by regulating arginine and proline metabolism

摘要

Papaya fruit is easily affected by low temperature, causing chilling injury (CI). In thisstudy, the exogenous arginine was applied in the storage of postharvest papayafruit and it was found that 0.8 mM arginine treatment significantly alleviated CI ofpapaya fruit. Arginine treatment promoted the accumulation of polyamines (PAs),which might be ascribed to the increased activities of arginase, arginine decarboxylase(ADC), ornithine decarboxylase (ODC), and S-adenosylmethioninedecarboxylase(SAMDC). A higher accumulation of proline was found in arginine-treatedpapayafruit, which may be due to increased activity of ornithine-δ-aminotransferase(OAT)and Δ~1-pyrroline-5-carboxylateacid synthase (P5CS) and inhibited activity of prolinedehydrogenase (PDH). In addition, arginine treatment increased higher nitric oxidesynthase (NOS) activity and promoted the generation of nitric oxide (NO). The resultsof this study indicate that exogenous arginine may improve the chilling tolerance ofpostharvest papaya fruit by regulating arginine and proline metabolism.