AUTHOR=Luo Zhenyu , Zhang Jieru , Xiang Miaolian , Zeng Jiaoke , Chen Jinyin , Chen Ming 

TITLE=Exogenous melatonin treatment affects ascorbic acid metabolism in postharvest ‘Jinyan’ kiwifruit

JOURNAL=Frontiers in Nutrition

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.1081476

DOI=10.3389/fnut.2022.1081476

ISSN=2296-861X

ABSTRACT=<p>Ascorbic acid (AsA) is an important nutritious substance in fruits, and it also can maintain the biological activity of fruits during storage. This research investigated the effect of exogenous melatonin (MT) on AsA metabolism in postharvest kiwifruit. Our results indicated that exogenous MT delayed the decrease of fruit firmness and titratable acid (TA), inhibited the increase of soluble solids content (SSC), reduced the respiration rate and ethylene production, and maintained a higher AsA content in kiwifruit during storage. The high expression of L-galactose pathway key genes in the early storage and regeneration genes in the later storage maintained the AsA content in postharvest kiwifruit. MT treatment enhanced the expression levels of AsA biosynthesis (<italic>AcGME2</italic>, <italic>AcGalDH</italic>, and <italic>AcGalLDH</italic>) and regeneration (<italic>AcGR</italic>, <italic>AcDHAR</italic>, and <italic>AcMDHAR1</italic>) genes. Meanwhile, the expression of the degradation gene <italic>AcAO</italic> was inhibited in MT-treated kiwifruits.</p>