Determination of Predominant Organic Acid Components in <i>Malus</i> Species: Correlation with Apple Domestication

• Main Authors: Baiquan Ma, Yangyang Yuan, Meng Gao, Cuiying Li, Collins Ogutu, Mingjun Li, Fengwang Ma
• Format: Article
• Language: English
• Published: MDPI AG 2018-10-01
• Series: Metabolites
• Subjects: malic acid; citric acid; HPLC; genetic relationship
• Online Access: https://www.mdpi.com/2218-1989/8/4/74

Significant variation in organic acid components was detected in mature fruits of 101 apple accessions using high-performance liquid chromatography. The <i>Malus</i> species predominantly accumulated malic acid and citric acid, whereas wild fruits exhibited significantly higher levels of organic acid content than that in cultivated fruits. Differential accumulation patterns during fruit developmental stages was detected between malic acid and citric acid, thus suggesting a complex genetic regulation mechanism of organic acid metabolism in apple fruit. A highly positive correlation was detected between fruit total organic acid content with malic acid and citric acid content, thus suggesting that malic acid and citric acid are the principal determinants of apple fruit acidity. In contrast to malic acid, citric acid was predominantly detected in partial wild apples, while extremely low to undetectable concentrations of citric acid were observed in cultivated apple fruits; this is likely due to the genetic effects of parental characters. Our results provide vital information that could be useful for future studies on genetic analysis and improvement of organic acid accumulation in apple fruits.