Plant responses to geminivirus infection: guardians of the plant immunity

Abstract

Background Geminiviruses are circular, single-stranded viruses responsible for enormous crop loss worldwide. Rapid expansion of geminivirus diversity outweighs the continuous effort to control its spread. Geminiviruses channelize the host cell machinery in their favour by manipulating the gene expression, cell signalling, protein turnover, and metabolic reprogramming of plants. As a response to viral infection, plants have evolved to deploy various strategies to subvert the virus invasion and reinstate cellular homeostasis. Main body Numerous reports exploring various aspects of plant-geminivirus interaction portray the subtlety and flexibility of the host–pathogen dynamics. To leverage this pool of knowledge towards raising antiviral resistance in host plants, a comprehensive account of plant’s defence response against geminiviruses is required. This review discusses the current knowledge of plant’s antiviral responses exerted to geminivirus in the light of resistance mechanisms and the innate genetic factors contributing to the defence. We have revisited the defence pathways involving transcriptional and post-transcriptional gene silencing, ubiquitin-proteasomal degradation pathway, protein kinase signalling cascades, autophagy, and hypersensitive responses. In addition, geminivirus-induced phytohormonal fluctuations, the subsequent alterations in primary and secondary metabolites, and their impact on pathogenesis along with the recent advancements of CRISPR-Cas9 technique in generating the geminivirus resistance in plants have been discussed. Conclusions Considering the rapid development in the field of plant-virus interaction, this review provides a timely and comprehensive account of molecular nuances that define the course of geminivirus infection and can be exploited in generating virus-resistant plants to control global agricultural damage.

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“…The role of insect vectors, which is the key factor in the spread of begomoviruses, also contributes to their evolution ( Seal et al, 2006 ; Materatski et al, 2021 ). The adaptive response of co-evolution among viruses and insects is supported by the continual and circulative dispersal of the virus in the insect vector and the direct connection between begomoviruses and insects ( Nawaz-ul-Rehman and Fauquet, 2009 ; Gupta et al, 2021 ).…”

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“…Therefore, selecting targets within the viral genome is a crucial factor in conquering durable resistance. In this perspective, non-coding targets are more efficient over coding regions as they embed the key elements for virus replication and pathogenicity maintenance [77]. Furthermore, detecting the potential host factors involved in the resistance during plant-geminivirus interaction, multiplexed genetic engineering tools directing multiple targets, and targeted deletion in viral genomes can assist in developing disease-free plants and counteracting the emergence of CRISPR-resistant BGVs.…”

P25 and P37 proteins encoded by firespike leafroll-associated virus are viral suppressors of RNA silencing

“…Over the past two decades, it has been well demonstrated that host RNA-directed DNA methylation (RdDM)-mediated TGS is one of the most effective defense responses against geminiviruses due to their DNA replication in the host nucleus ( Raja et al, 2008 ; Zhong et al, 2017b ; Zarreen and Chakraborty, 2020 ; Gupta et al, 2021 ). In turn, geminiviruses evolve various VSRs to interfere with the host RdDM-mediated TGS ( Hanley-Bowdoin et al, 2013 ; Wang et al, 2019 ; Jin et al, 2021 ; Zhou, 2021 ).…”