Geminiviruses: Molecular biodiversity and global distribution in Jatropha

Jatropha is one of the most important crops for biodiesel production. Its yield has been severely hampered due to mosaic disease caused by geminiviruses. The Jatropha infecting geminiviruses reported from all over the world have significant genetic diversity. Begomoviruses infecting Jatropha are reported from the United States of America, Asia and Africa. There exist 85 complete nucleotide sequences of Jatropha geminiviruses, including 72 DNA-A segments, 11 DNA-B segments and 2 DNA-beta sequences. Majority of submitted sequences are from Kenya and India. The different geminiviruses identify Jatropha either as their primary host or as an alternate host, for a successful infection. The geminiviruses require a specific host for causing the disease; however, reports suggest that the geminiviruses evolve to change their host plant specificity to infect a new host. Jatropha also became an alternate host to geminiviruses from other crops. In this review, we discuss the geminivirus infection process, the global spread of geminiviruses leading to change in host preferences, the array of histological, metabolic and molecular changes reported in Jatropha following geminivirus infection. Also, the importance of RNA interference (RNAi) strategy, as the forefront of research towards sustained control of geminiviral diseases, is emphasized.