Manipulation of hosts and vectors by plant viruses and impact of the environment

The effect of environmental factors on the efficiency of plant virus transmission is extremely difficult to predict, because they obviously impact concomitantly multiple steps of the complex three-way plant-virus-vector interaction. This review summarizes the diversity of the relationship between plants, viruses and insect vectors, and highlights the numerous phases of this process that can be altered by the virus in ways that can potentially enhance its transmission success. Many of the reported cases are often considered to be possible viral manipulations acting through modifications of the physiology of the host plant, indirectly reaching to the insect vector. Plants are extremely responsive to environmental fluctuations and so interferences with these putative viral manipulations are highly expected. The role of environmental factors in plant virus transmission can thus be envisaged solely in the context of this complexity. It is only briefly evoked here because this field of research is in its infancy and currently suffers from an impressive lack of experimental data.