Volatile Profile and Biosynthesis of Post-harvest Apples are Affected by the Mechanical Damage

Abstract

Mechanical damage to fruit causes flavor changes during post-harvest supply chains. It is important to identify the main volatiles and explore their biosynthesis mechanism. In this study, the volatile changes in apples caused by mechanical damage were analyzed by gas chromatography-ion mobility spectrometry. Hexanal and ethyl acetate were accumulated and identified as potential volatile biomarkers to detect damaged apples. The study on the lipoxygenase (LOX) pathway and transcription factors (TFs) shows that mechanical damage up-regulated the expression of <i>MdLOX-like</i>, <i>MdLOX3b</i>, <i>MdLOX7b</i>, <i>MdLOX7c</i>, <i>MdLOX2a</i>, and <i>MdAAT</i> in the LOX pathway and that of one MYB TF (<i>MdMYB-like</i>), five ERF TFs (<i>MdERF073</i>, <i>MdERF003</i>, <i>MdERF114</i>, <i>MdERF15</i>, and <i>MdERF2</i>), and five WRKY TFs (<i>MdWRKY23</i>, <i>MdWRKY17</i>, <i>MdWRKY46</i>, <i>MdWRKY48</i>, and <i>MdWRKY71</i>). Notably, <i>MdAAT</i> was significantly correlated to <i>MdMYB-like</i>, <i>MdWRKY23</i>, <i>MdWRKY71</i>, <i>MdERF15</i>, and <i>MdERF2</i>. Thus, TFs may attribute to the accumulation of hexanal and ethyl acetate by regulating the expression of LOX pathway-related genes.