Functional role of geminivirus encoded proteins in the host: Past and present

During plant–pathogen interaction, plant exhibits a strong defense system utilizing

diverse groups of proteins to suppress the infection and subsequent establishment

of the pathogen. However, in response, pathogens trigger an anti-silencing mecha-

nism to overcome the host defense machinery. Among plant viruses, geminiviruses

are the second largest virus family with a worldwide distribution and continue to be

production constraints to food, feed, and fiber crops. These viruses are spread by

a diverse group of insects, predominantly by whiteflies, and are characterized by a

single-stranded DNA (ssDNA) genome coding for four to eight proteins that facili-

tate viral infection. The most effective means to managing these viruses is through an

integrated disease management strategy that includes virus-resistant cultivars, vec-

tor management, and cultural practices. Dynamic changes in this virus family enable

the species to manipulate their genome organization to respond to external changes

in the environment. Therefore, the evolutionary nature of geminiviruses leads to new

and novel approaches for developing virus-resistant cultivars and it is essential to study

molecular ecology and evolution of geminiviruses. This review summarizes the multi-

functionality of each geminivirus-encoded protein. These protein-based interactions

trigger the abrupt changes in the host methyl cycle and signaling pathways that turn

over protein normal production and impair the plant antiviral defense system. Study-

ing these geminivirus interactions localized at cytoplasm-nucleus could reveal a more

clear picture of host–pathogen relation. Data collected from this antagonistic relation-

ship among geminivirus, vector, and its host, will provide extensive knowledge on their

virulence mode and diversity with climate change.