biologia plantarum

Biologia plantarum 48:419-423, 2004 | DOI: 10.1023/B:BIOP.0000041096.21583.61

TMV-RNA Biosynthesis in the Light-Green and Dark-Green Regions of Tobacco Leaves

M. Šindelářová¹, L. Šindelář¹

¹ Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague 6, Czech Republic, e-mail: s

Changes in the proteins, chlorophyll, virus content and activity of key enzymes of viral RNA biosynthesis were investigated in the light- and dark-green regions of tobacco leaves systemically infected with tobacco mosaic virus. The protein content was increased to 118 % in the dark-green islands in contrast to 60 % in the light-green regions when compared with the control healthy leaves. The comparative analysis of soluble proteins from healthy and light- or dark-green regions of leaves by means of SDS-PAGE revealed that the main soluble proteins are equal in pattern but differ in quantity. The contents of chlorophylls did not differ from healthy tissues in the dark-green islands but were considerably lower in the light-green regions. The content of virus in light-green tissues was about 10 times higher than in the dark-green islands. The activities of key enzymes of oxidative pentosephosphate cycle -- glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase -- did not differ from healthy tissues in the dark-green islands but were considerably higher in the light-green tissues when compared with healthy control. Similar relationships were observed for ribonuclease, phosphomonoesterase and phosphodiesterase activities. The biosynthesis of viral RNA in the dark-green islands is probably restricted by the steady (or reduced) activities of key enzymes of these metabolic pathways.

Keywords: chlorophyll; glucose-6-phosphate dehydrogenase; Nicotiana tabacum L.; phosphodiesterase; 6-phosphogluconate dehydrogenase; phosphomonoesterase; proteins; ribonuclease; tobacco mosaic virus

Subjects: chlorophyll, light- and dark-green regions of leaf; glucose-6-phosphate dehydrogenase; leaf, light- and dark-green regions; Nicotiana tabacum; 6-phosphogluconate dehydrogenase; phosphodiesterase; phosphomonoesterase; protein, viral RNA biosynthes; ribonuclease; RNA biosynthesis, virus; tobacco mosaic virus; tobacco, light- and dark-green regions of leaf

Published: September 1, 2004  Show citation