Analysis of the Expression Pattern of Endo-β-1,4-Glucanase Gene during Development and Maturation of Chili Pear

Abstract:

The expression patterns of PbEG3 and PbEG4, which encode endo-β-1,4-glucanase (EGase), were analyzed during fruit development, maturation, and senescence of the chili pear (Pyrus bretschneideri Rehd. Cv. Chili). Both PbEG3 and PbEG4 showed the highest expression during the fruit development period. The highest levels of expression of PbEG3 and PbEG4 were found to be 0.31 and 0.14, at 70 d and 110 d after anthesis, respectively. At 130 d after anthesis, the expression levels of PbEG3 and PbEG4 decreased to 0.003 and 0.005, respectively. The expression pattern of PbEG4 was found to be consistent with the enzyme activity of EGase. During storage at 0 ℃, the expression of both PbEG3 and PbEG4 exhibited a decreasing trend, and was the highest on the day of harvest. PbEG3 expression was lowest at 60 d after harvest, and then increased slightly, while PbEG4 expression was consistently low during storage. Postharvest acetylsalicylic acid (ASA) treatment decreased fruit weight loss, inhibited the increase of soluble pectin content, reduced the activity of EGase, and delayed the degradation of cellulose, thereby delaying the processes of fruit ripening and senescence. These results indicated that PbEG3 and PbEG4 might be related to the growth and development of chili pear, but not the senescence process.