Relationship between concentration of plum pox virus and content of pigments in virus-infected symptomatic apricot leaves.

Besides other factors, occurrence of plum pox virus (PPV)-caused spots and mosaic symptoms on leaves of stone fruits are known to influence important physiological functions including production of assimilates. Apricot (Prunus armeniaca L.) seedlings were used as a test material for typical manifestation of symptoms of the disease on the foliage. The relations of the abovementioned visual symptoms to the virus and pigments concentrations in leaves have so far not been known sufficiently. We detected PPV only in symptomatic leaf tissue of the infected apricot. In the green tissue of the same leaves, the double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) of the virus was negative. The content of pigments was changed by PPV infection. In the symptomatic leaf tissues, the content of chlorophylls "a" and "b" was lower, and the content of carotenoids was higher in comparison to the respective controls. We conclude that the PPV infection could cause the change in the content of particular leaf pigments leading to the decreased yield of photosynthesis which in turn could influence the sugar metabolism in the infected trees.