Effect of High Energy Electron Beam Irradiation on Cell Wall Degradation Related Enzyme Activities and Gene Expressions of Kiwifruit

Abstract

‘Hayward’ kiwifruits were used as the test materials to be irradiated with high energy electron beams at doses of 0 (control), 300, 400 and 500 Gy. The fruits were stored at 0~1 ℃, RH 90%~95% for 90 d. The effects of electron beam irradiation on fruit firmness, cell wall components, softening-related enzyme activities and gene expressions were analyzed. The results showed that the high energy electron beam irradiation kept the firmness, effectively inhibited the degradation of cell wall skeletal material (protopectin and cellulose) and delayed the postharvest ripening and softening of kiwifruits. In further, high energy electron beam irradiation significantly inhibited the activities of polygalacturonase (PG), pectin methylesterase (PME), β-D-galaetosidase (β-Gal) and cellulase (Cx), and reduced the expressions of genes encoding PG, PME, β-Gal and Cx. Among the three treatments, 400 Gy high-energy electron beam irradiation showed the best effect on inhibiting cell wall degrading enzyme activity and gene expression, retaining the integrity of cell structure, and maintaining fruit firmness during storage. The study provided a theoretical basis for the use of high-energy electron beams in postharvest kiwifruit preservation.

Keywords

• high energy electron beam irradiation
• kiwifruit
• softening
• cell wall metabolism
• gene expression