Comparative Study of Volatile Compounds and Expression of Related Genes in Fruit from Two Apple Cultivars during Different Developmental Stages

• Main Authors: Shuaishuai Feng, Chengtai Yan, Tianhao Zhang, Miaomiao Ji, Ru Tao, Hua Gao
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Molecules
• Subjects: apple cultivars; fruit development; fruit maturation; volatile compounds; esters; gene expression
• Online Access: https://www.mdpi.com/1420-3049/26/6/1553

Aromatic volatile compounds are important contributors to fruit quality that vary among different cultivars. Herein, headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was used to determine changes in volatile compounds and related gene expression patterns in “Ruixue” and “Fuji” apples (<i>Malus domestica</i> Borkh.) during fruit development and maturation. Volatile compounds detected in the fruit of both cultivars exhibited similar trends across different developmental stages. In the early stages of “Ruixue” fruit development (60 days after full bloom), there were fewer volatile compounds, mainly aldehydes (87.0%). During fruit maturation (180 days after full bloom), the types and amounts of volatile compounds increased, mainly including esters (37.6%), and alkenes (23.2%). The total volatile concentration, the types of major volatile compounds, and their relative content in both cultivars varied across different stages. Gene expression analysis indicated that the upregulation of <i>MdLOX</i>, <i>MdAAT2</i>, and <i>MdADH3</i> was associated with increased aroma compound content, especially esters, during fruit development in both cultivars. Changes in the expression of <i>MdArAT</i>, <i>MdACPD</i>, <i>MdADH3</i>, <i>MdAAT2</i>, and <i>MdLOX</i> may lead to differences in volatile compounds between apple cultivars.