Artículos de revistas
Histopathology of black spot symptoms in sweet oranges
Fecha
2012Registro en:
EUROPEAN JOURNAL OF PLANT PATHOLOGY, DORDRECHT, v. 133, n. 2, supl. 1, Part 6, pp. 439-448, JUN, 2012
0929-1873
10.1007/s10658-011-9917-9
Autor
Marques, João Paulo Rodrigues
Sposito, Marcel Bellato
Mello, Alexandre Furtado Silveira
Amorim, Lilian
Mondin, Matheus
Gloria, Beatriz Appezzato da
Institución
Resumen
In Brazil, citrus black spot (CBS) caused by Guignardia citricarpa is a major disease that has different symptoms on fruit. In this study, fruit of Citrus sinensis infected by G. citricarpa and showing the symptoms false melanosis, freckle spot and hard spot were cross-sectioned and analysed anatomically and histochemically by light microscopy. Immuno-histological assays were performed. All symptoms were accompanied by a thickening of the cuticle. False melanosis lesions did not contain pycnidia and remained restricted to the epicarp or to the first layers of the mesocarp. The stomata in this type of lesion showed phenolic compounds in the guard cells and in the sub-stomatal chamber. In some samples, the guard cells and their surrounding cells lysed, and a wound meristem began to form underneath them. Freckle spot and hard spot lesions had very similar histological alterations to the epicarp and mesocarp, but in our samples only hard spot lesions contained pycnidia. Both of these symptoms were accompanied by protein inclusions. Epidermal and sub-epidermal cells located in the oil-gland region were obliterated, causing alterations in these structures. All symptoms had regions that stained strongly for lipids and phenols.