Lanthanum nitrate regulates the content of vitamin C through its biosynthesis, regeneration and degradation in the fruit of strawberry

Abstract

This study investigated the effects of lanthanum nitrate (La(NO3)3) on the activities and the transcript levels of enzymes in the biosynthesis, regeneration and degradation of vitamin C (Vc) and the content of Vc in the fruit of strawberry at different periods of growth and development, as well as the average weight of fruit at mature period. The results showed that low concentrations of La(NO3)3 significantly increased the content of Vc by increasing the activities and the transcript levels of recycling enzymes glutathione reductase (GR), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR) and biosynthetic enzyme l-galactono-1,4-lactone dehydrogenase (GalLDH), and decreasing the activity and the transcript level of degrading enzyme ascorbate oxidase (AO). However, high concentrations of La(NO3)3 significantly decreased the content of Vc by increasing the activities and the transcript levels of APX and AO, and decreasing the activities and the transcript levels of GR, DHAR, MDHAR and GalLDH. Meanwhile, our results also showed that low concentrations of La(NO3)3 significantly increased the average weight of fruit at mature period, compared with control and high concentrations of La(NO3)3. Our results suggested that low concentrations of La(NO3)3 could improve the content of Vc by regulating the activities and the transcript levels of enzymes in its biosynthesis, regeneration and degradation.