Sugars and organic acids in plum fruit affected by Plum pox virus.

BACKGROUND: Plum pox virus (PPV) causes severe economic losses in stone fruit production, but little is known about its effect on plum fruit composition. In this study, the influence of PPV on sugars and organic acids was evaluated in a susceptible plum (Prunus domestica L.) cultivar. RESULTS: PPV infection significantly affected the content and composition of sugars and organic acids. The composition of necrotic tissue was modified the most. A short-time infected tree yielded fruit with similar sugar composition to fruit from a healthy tree, but the decline of organic acids was faster. Prematurely ripened symptomatic fruit had reduced fruit weight and low sugar content. CONCLUSION: Infected trees of the studied cultivar produce fruit of inferior quality. Fruits are not suitable for processing, especially when most of them exhibit visual symptoms of PPV infection. © 2016 Society of Chemical Industry.

Effect of Plum pox virus on chemical composition and fruit quality of plum.

The quality of fruit from PPV (Plum pox virus)-infected plum (Prunus domestica L.) trees was investigated during the last 3 weeks of ripening using healthy tree (T3), tree with short-term infection (T2), and tree with long-term infection (T1). The pomological variables (presence of necrosis on fruit, color of fruit, color of flesh, firmness, soluble solids content, and fruit weight) and composition of nutritive compounds (sugars and organic acids) and bioactive compounds (phenolics: anthocyanins, flavonols, and hydroxycinnamic acids) were evaluated. The results indicated that the PPV infection modified the ripening process (the most in T1) and the composition of nutritive and bioactive compounds in the healthy-looking part of the fruit. Long-term infected tree (T1) yielded fruit with the poorest pomological traits and with the most modified composition of nutritive and phenolic compounds. The short-term PPV infected tree also produced fruit with significantly altered phytochemicals composition, although the pomological traits had not changed significantly.

Development and inter-laboratory evaluation of real-time PCR assays for the detection of pospiviroids.

Assays based on real-time PCR (TaqMan) that can detect a number of viroids in the genus Pospiviroid have been developed and evaluated. The assays are designed for detecting viroids from tomato leaf material but detection from other solanaceous hosts of these viroids has been confirmed. These methods have been validated by nine laboratories and comprise a reliable set of assays for the detection of CEVd, TASVd, CLVd and a generic assay which will detect the six viroids of concern to European tomato growers: PSTVd, TCDVd, CEVd, CLVd, TASVd and CSVd.