The mechanism and the control of peel pitting of citrus fruits
Z. Li, J. Fan, X. Gao, Y. Yang, W. Deng and L. Yuan
ISHS Acta Horticulturae 837:287-292. 2009.
2009
บทคัดย่อ
Citrus is one of the most important fruit in the world. But the fruit of some varieties is prone to develop peel pitting, which has been described as a severe disorder with characteristics of the extensive collapsed areas of the flavedo and part of the albedo that becomes brown with time. The external quality and consequently the market value of the fruit were decreased by peel pitting. The mechanism of the disorder is still unclear, and there are no effective control techniques. To understand the molecular mechanism of this physiological disorder, ‘Fengyuan 72-1’ navel orange (Citrus sinensis Osbeck) was used to isolate and identify the genes involved in the process of peel pitting. A suppression subtractive hybridization (SSH) library was constructed to identify differentially expressed genes in peel pitting of navel orange fruit. Sequence analysis showed that a lot of genes including the CsCAB, CsCP, CsNAC, etc., were involved in the process. The expression analysis indicated that some of these genes had relationship with the peel pitting. For seeking the control techniques, the navel orange fruits were treated with different concentrations of CaCl2 and/or Ca(NO3)2 in the orchard and/or postharvest. The results showed that the treatment of 1% CaCl2 could effectively decrease the development of peel pitting of fruit either in the field or postharvest. After 110 days storage, the pitting index of navel orange treated with 1% CaCl2 was significantly lower than that of the control. Thus, the preharvest or postharvest calcium treatment could be used as an efficient approach to reduce the development of peel pitting of navel orange fruits.