Khalid Naveed, Muhammad R. Shafiq, Ahmed Raza



Citrus tristeza virus (CTV) produces the most damaging disease of citrus worldwide and is a continuous threat to the citrus industry. It is primarily spread through infected root-stock and brown citrus aphid in a semi-persistent manner. Infected trees produce small sized and poor quality fruit, and in severe cases tree dies. Sour orange rootstock is highly susceptible to CTV. Several mild and severe strains have been identified which produce from invisible- to- visible symptoms in diseased plants. Existence of multiple CTV strains in nature is a challenge for CTV management. Symptomless infection in certain citrus species results in the inoculum build up and further spread of the disease. Breeding for CTV resistance genes is a long and time-consuming process that takes 8-10 years before a CTV resistant variety is developed. Genomic manipulation of CTV genome is challenging due to its larger genome size. Modern biotechnological tools can be used to control this disease and to prevent its spread in the future. However, CTV offers a valuable research tool for its role as a stable marker in genetic transformation of plants. This review highlights the challenges in developing resistant citrus cultivars against CTV and future prospects of CTV and is an update to the research status of CTV.


Citrus tristeza virus; resistance breeding; disease management; genetic transformation.

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