FOOD SCIENCE ›› 2021, Vol. 42 ›› Issue (3): 211-218.doi: 10.7506/spkx1002-6630-20200130-287

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Effects of Penicillium expansum Infection on Membrane Phospholipid Metabolism of Apple Fruit

PENG Hui, GONG Di, WEI Yanan, YANG Qian, ZONG Yuanyuan, Dov PRUSKY, Edward SIONOV, BI Yang   

  1. (1. College of Food Science and Engineering, Gansu Agricultural University, Lanzhou 730070, China; 2. Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, Rishon Lezion 7505101, Israel)
  • Published:2021-02-25

Abstract: Objective: To explore the effect of Penicillium expansum infection on the membrane permeability and membrane phospholipid metabolism of apple fruits. Methods: ‘Red Delicious’ apple fruits were used in this study. Changes in cell membrane permeability, key enzyme activities involved in membrane phospholipid metabolism, and substrate and product contents were measured in the junction between diseased and healthy parts of apples inoculated with P. expansum. Results: There was no obvious change in the lesion diameter of fruit in the early stage of infection by P. expansum (before 2 days), and the lesion diameter and cell membrane permeability of fruit increased significantly in the late stage of infection (after 2 days). The activity of phospholipase A2 (PLA2), phospholipase C (PLC) and phospholipase D (PLD), and the content of phosphatidic acid (PA) in infected fruits increased continuously, while the contents of phosphatidylcholine (PC) and phosphatidylinositol (PI) significantly decreased. Significant variation in the contents of PC, PI and PA occurred between the infected and control groups at the late stage of infection. In addition, the content of unsaturated fatty acid increased rapidly at the early stage of infection, and on the second day of infection, the contents of oleic acid, linoleic acid and linolenic acid were 31.58%, 55.57% and 43.67% higher than those in the control group, respectively. The content of saturated fatty acid increased significantly at the late stage of infection, and on the sixth day, the contents of palmitic acid and stearic acid were 49.46% and 43.39% higher than those in the control group, respectively. The unsaturation degree of fatty acids in the infected group was higher than that in the control group at the early stage but lower at the late stage of infection. The correlation analysis indicated that there was a very significantly positive correlation between cell membrane permeability and the activity of PLA2, PLC and PLD, as well as palmitic acid, stearic acid and PA contents. A highly significantly negative correlation was found between cell membrane permeability and PC and PI contents. Conclusion: P. expansum infection can activate phospholipase, promote the degradation of phospholipid and the release of fatty acids, and destroy the integrity of the cell membrane in apple fruit. The rapid release of unsaturated fatty acids at the early stage of infection may be related to disease resistance.

Key words: apple; Penicillium expansum; cell membrane integrity; phospholipid metabolism

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