A comprehensive insight on the main physiological biochemical and related genes expression changes during the development of superficial scald in “Yali” pear

Author:Jingang He , Yunxiao Feng , Yudou Cheng , Meng Wang and Junfeng Guan

Superficial scald is a serious physiological disorder in “Yali” pear (Pyrus
      bretschneideri Rehd. cv. Yali) after long-term cold storage. Changes in
      superficial scald, ethylene production, α-farnesene and phenylpropane
      metabolism with associated gene expression in “Yali” pear treated with
      and without (control) 1-methylcyclopropene (1-MCP) were investigated.
      Compared with the control group (without 1-MCP), 1-MCP (1.0 µl L−1
      significantly lowered the superficial scald index after 180 days of cold storage.
      During cold storage and shelf life, the contents of α-farnesene, conjugated
      trienols, chlorogenic acid, and epicatechin in the peel were reduced, while
      quercetin was enhanced in 1-MCP-treated fruit, and the expression of genes
      associated with ethylene synthesis (ACS1, ACO1), receptors (ETR2, ERS1) and
      signal transduction (ERF1), α-farnesene metabolism (AFS1, HMGR2, GST7),
      phenolic biosynthesis (PAL1, C4H1, C4H2, HCT3, 4CL2, C3H), and oxidases
      (PPO1, PPO5, and LAC7) were significantly downregulated by 1-MCP. These
      results suggested that the onset and development of superficial scald was
      closely related to the ethylene receptor, conjugated trienols, chlorogenic acid
      and epicatechin and related genes expression in “Yali” pear.

Key words:pear, superficial scald, phenolics, α-farnesene, ethylene