BSMV infection inhibits chlorophyll biosynthesis in barley plants

Protochlorophyllide forms: their phototransformation in the greening process and the ultrastructure of the etioplasts were studied in BSMV-infected barley plants. The aim of this work was to determine whether the chlorotic symptoms caused hy the infection of this virus result from inhibition of chlorophyll biosynthesis. 77 K fluorescence emission spectra of dark-grown, flash-illuminated and re-darkened leaves and transmission electron micrographs suggested that the BSMV infection did not cause specific changes in chlorophyll biosynthesis or in chloroplast development. However, infection accelerated senescence and inhibited or delayed chlorophyll biosynthesis similar to general stress effects. (C) 2000 Academic Press.