Sun Yingjie,Zhang Xinyue,Jiang Yaping,Wang Jihan,Li Bingru,Zhang Xinhua,Li Xiaoan,Li Fujun
Ethylene response factors 2 (ERF2) belongs to the AP2/ERF transcription factor family and plays key roles in ethylene signal transduction . The roles of MdERF2 in apple ( Malus × domestica ) cuticular wax synthesis regulated by ethylene were studied in this work. Result shows that MdERF2 overexpression (ERF2-OE) up-regulated the expression levels of wax-related synthetic genes long-chain acyl-CoA synthetase 2 ( MdLACS2), Wax synthase1 ( MdWSD1), Eceriferum 4 ( MdCER4) and Eceriferum 6 ( MdCER6) , while has no effect on the transcription of Eceriferum 1 ( MdCER1) , and shows different regulation effects on the expression levels of mid-chain alkane hydroxylase 1 ( MdMAH1) between calli and fruit. Furthermore, different MdERF2 expression levels changed the apparent structure of the apple cuticular wax and positively regulated the total wax accumulation. ERF2-OE also increased alkane and alcohol production but decreased acid and ester contents. Thus, ethylene regulated the synthesis of apple cuticular wax at the transcriptional level through MdERF2, thereby altering the wax structure and composition.
Hua Huang,Xuemei He,Qingming Sun,Guoming Liu,Yayuan Tang,Jian Sun
Pitaya ( Hylocereus undatus ) fruit is susceptible to pathogens that induce fruit decay after harvest. Cuticular waxes covering the outermost plant surfaces are the first site of plant-environment interactions; however, their changes in response to fruit decay are under-researched. Herein, the surface microstructures and chemical composition of wax on pitayas, as well as their changes in response to fruit decay, were comparatively studied. The varieties ‘Baishuijing’ (BSJ) and ‘Hongshuijing’ (HSJ) were examined after harvest. The fruit appearance, morphology, and wax composition differed between cultivars. The surface of both pitaya cultivars was smooth, although traces of granules and a thicker lipid layer were observed using histochemical staining in HSJ than in BSJ, as well as a higher cuticular wax content. Fruit decay rate increased rapidly in both cultivars under room storage conditions, and greater sensitivity to pathogens was found in BSJ than HSJ. As well as the occurrence of fruit decay, the total wax coverage, very-long-chain primary alcohols, aldehydes, fatty acids, and triterpenoids decreased in BSJ, while remaining relatively stable in HSJ. Correspondingly, the relative gene expression levels of HuKCS11 (−1, 2, and 3) , HuKCS17 , and HuKCS19 (for the elongation of very-long-chain fatty acids), HuCER1 (for aldehydes or n -alkanes), HuFAR (−1 and 2) (for primary alcohols), HuBAS1 (−1, 3, and 4) (for β-amyrin), and HuLUS1 (for lupeol) were considerably modified following fruit senescence during storage. The difference in surface topography and wax accumulation between cultivars might have affected pathogen susceptibility after harvest. These results may help when choosing varieties of pitaya based on surface characteristics and cuticular chemicals. They may also help to optimize strategies for postharvest preservation and storage.
危险品化学品经营许可证（带存储）