Grapevine Leaf Roll Disease and Grapevine Leaf Roll Associated Virus-3: A Review
Grapevine leaf roll disease has vast impact on productivity, growth and vigor of grapevine plant. This disease has alone caused more economic losses globally than any other known diseases of grapevines. It is responsible for damaging wine, grape juice, and table grape cultivars, as well as rootstocks. GLD is a complex disease, eleven viruses are associated with GLD (each named Grapevine leaf roll-associated virus followed by a number) which belongs to family Closteroviridae. Out of eleven GLD associated viruses Grapevine leaf roll-associated virus 3 (GLRaV-3) has major role in spreading GLD disease in grapevines. It belongs to genus Ampelovirus of Closteroviridae family. It is transmitted by grafting, vegetative propagation and insects like Mealybugs (Pseudococcidae) and soft scales (Coccidae). It is difficult to identify disease related viruses since most affected plants have mixed infection. It becomes further challenging when dissimilar viruses can cause similar symptoms. Low virus titer, uneven virus distribution in vineyards and symptomless rootstocks and white cultivars are common issues in mixed infections. This review summarizes origin, distribution, genomics and overall impact of (GLRaV-3) on grape plants and its importance related to GLD.