Phenyllactic acid regulated salicylic acid biosynthesis and organic acids metabolism in Zaosu pear fruit during storage

Acidity plays a crucial role in determining the sensory attributes of the majority of fresh fruit and vegetables. This study investigated the variations of organic acids metabolism and salicylic acid biosynthesis in Zaosu pears after postharvest phenyllactic acid dipping. Results elucidated that phenyllactic acid dipping improved the contents of malic, succinic, citric, and salicylic acid in Zaosu pears. Phenyllactic acid also improved the enzymatic activities and gene transcription levels of phosphoenolpyruvate carboxylase, mitochondrial citrate synthase, mitochondrial aconitase, and NADP-isocitrate dehydrogenase, whereas declined NADP-dependent malate (NADP-ME) and cytoplasmic aconitase activities as well as PbNADP-ME transcription level in pears. Moreover, the enzymatic activities and gene transcription levels of phenylalanine ammonia lyase and shikimate dehydrogenase as well as the gene transcription levels of 3-dehydroquinate synthase, d-arabino-heptulosonate-7-phosphate synthase, chorismate synthase, shikimate kinase, isochorismate synthase, 5-enolppyruvylshikimate-3-phosphate synthetase, avrPphB susceptible 3, enhanced pseudomonas susceptibility 1, enhanced disease susceptibility 5, and chorismate mutase in Zaosu pears were promoted by phenyllactic acid treatment. Taken together, phenyllactic acid can regulate the pivotal enzyme activity and gene transcription in organic acids metabolism and salicylic acid biosynthesis to sustain the flavor and freshness of Zaosu pears.