Modulation of host plant immunity by Tobamovirus proteins

CONTI, G.; RODRIGUEZ, M. C.; VENTURUZZI, A. L.; ASURMENDI, S.

ANNALS OF BOTANY

OXFORD UNIV PRESS

Año: 2016

0305-7364

Background To establish successful infection, plant viruses produce profound alterations of host physiology, disturbingunrelated endogenous processes and contributing to the development of disease. In tobamoviruses, emergingevidence suggests that viral-encoded proteins display a great variety of functions beyond the canonical rolesrequired for virus structure and replication. Among these, their modulation of host immunity appears to be relevantin infection progression. Scope In this review, some recently described effects on host plant physiology of Tobacco mosaic virus (TMV)-encoded proteins, namely replicase, movement protein (MP) and coat protein (CP), are summarized. The discussionis focused on the effects of each viral component on the modulation of host defense responses, through mechanismsinvolving hormonal imbalance, innate immunity modulation and antiviral RNA silencing. These effects aredescribed taking into consideration the differential spatial distribution and temporality of viral proteins during thedynamic process of replication and spread of the virus. Conclusion In discussion of these mechanisms, it is shown that both individual and combined effects of viralencodedproteins contribute to the development of the pathogenesis process, with the host plant?s ability to controlinfection to some extent potentially advantageous to the invading virus.Key words: Tobacco mosaic virus, replicase, coat protein, movement protein, immune response, salicylic acid, reactiveoxygen species, DELLA proteins, RNA silencing.