Distribution and molecular variability of begomoviruses affecting economically important crops in Cuba: epiphytiological element

Introduction The results presented here describe studies on the distribution, molecular variability and epiphytiology of begomoviruses in Cuba, mainly focused on those affecting tomato. The work presents prospection results that have allowed the examination of the distribution of these viruses among the main areas of tomato culture in the country, identifying those with the highest affectation and examining the main epidemiological factors infl uencing on the large rates of incidence and the high severity of the infestations, as well as monitoring and demonstrating the adaptability of TYLCV-IL(CU) to the agricultural ecosystems of Cuban tomato. Further knowledge on the molecular evolution of begomoviruses has been provided, evidencing their potential colonization of other ecological habitats such as pepper, bean and pumpkin cultures, which may function as natural, active reservoirs for TYLCV-IL(CU). Importantly, two new species of bipartite begomoviruses infecting tomato, pepper and tobacco crops are described, under the proposed names of Tobacco Yellow Crinkle Virus (TbYCV, infecting tobacco and pepper) and Tomato Yellow Leave Distortion Virus (ToYLDV, infecting tomato crops). The use of total DNA sequencing in symptomatically infected tobacco plants also detected the presence in this crop of another begomovirus which, although representing a variant of the previously known Euphorbia mosaic virus instead of a new species of the genus, is however detected in Cuba for the fi rst time. The identifi cation and partial sequencing of regions of taxonomic relevance demonstrated the presence and diversity of begomoviral populations in weeds, a very important topic given the potential interaction of these populations with economically important crops and their possible contribution to genetic diversity through recombination events that may give rise to new, more aggressive or better adapted viral species. The results obtained here arise from an integral approach to the study of the alterations to agricultural systems that includes both, biological and molecular changes shaping the emergence of a viral disease and its evolution towards increased severity in the interface between natural ecosystems and productive ecosystems, which are completely managed by man.