Effects of Grapevine Leafroll associated virus 3 (GLRaV-3) on plant carbon balance in Vitis vinifera L. cv. Giró Ros

Abstract

[eng] Phloem systemic viruses like Grapevine leafroll associated virus-3 (GLRaV-3) cause significant economic losses in many vineyards around the world. Previous studies have shown that this virus could limit carbon assimilation, without affecting aerial plant growth. However, most of the studies were focused only in the effects of the virus on photosynthesis, i.e. a reduction in the availability of fixed carbon, neglecting the importance carbon losses by respiration, not only in leaves, but in all plant tissues. In this study, we analysed the effects of GLRaV-3 on the plant carbon balance (PCB). The results showed an absence of virus effects on the total biomass increment despite the fact that there was a reduction in carbon assimilation. The discrepancy was found due to an adjustment of carbon losses by respiration caused by the presence of the virus, which compensated the lower carbon assimilation with the result that the total PCB was unaffected. The carbon balance estimated by measuring photosynthesis and respiration in different plant organs matched well with that measured as total biomass increments. In addition, upper leaves and roots were identified as the most sensitive parts of the plant to GLRaV-3 infection.