Changing surface wax compositions and related gene expression in three cultivars of Chinese pear fruits during cold storage

Author:Dan Li , Yudou Cheng , Zhonglin Shang and Junfeng Guan

The surface wax of fruit has a significant effect on abiotic stress and fruit quality.
      In this study, the composition of the waxes found on fruit surfaces and the related
      gene expression of three different pear cultivars (Xuehua, Yali, and Yuluxiang) were
      investigated during cold storage. The results showed that 35 wax compositions were
      found on the surfaces of the three pear cultivars, mainly including C29 alkane, three
      fatty acids, two esters, three aldehydes, three fatty alcohols, and three triterpenoids.
      The largest amount of C29 alkane, three fatty acids and two esters were found in
      Yuluxiang (YLX) on day 90, while aldehydes with carbons of C30 and C32 were the
      highest in Yali (YL). Xuehua (XH) showed the largest amount of C22 fatty alcohol on
      day 180 compared to YLX and YL. Larger amounts of triterpenoids were found in
      XH and YL when compared to YLX. The expression levels of fifteen wax related
      genes (LACS1, KCS2, KCS6, FDH, KCS20, GL8, CER10, CER60, LTPG1, LTP4,
      ABCG12, CER1L, CAC3, CAC3L, and DGAT1L) reached their peak at day 45 in YLX,
      compared to XH and YL, their expression levels in YLX were higher to different
      degrees. These results suggest that the different expression patterns of wax-related
      genes may be closely related to the difference in wax compositions of the surface wax
      of three pear cultivars.

Key words:Pear cultivar, Surface wax, Cold storage, Gene expression