A maize non- infectious clone from Sugarcane mosaic virus can move in detached tobacco leaves

Background: Infectious clones are copies of a virus genome produced in vitro or inside a vector and can infect inoculated healthy plants or cells. They are important tools to study the molecular biology of viruses. Questions: Is it possible to construct a Sugarcane mosaic virus infectious clone using methods suggested by other authors? Studied species: Sugarcane mosaic virus isolate Veracruz 1, Zea maize line B73, Nicotiana rustica. Methods: The Mexican viral isolate Sugarcane mosaic virus Veracruz 1 was used to construct an infectious clone after segment amplifications of the virus genome, intron insertion, and their further fusion by yeast homologous recombination. The clone was under the regulation of the Cauliflower mosaic virus 35S promoter and was tagged with the green fluorescent protein. Clones were then used to inoculate maize and tobacco plants and detached tobacco leaves. Results: The viral clone obtained did not produce symptoms in inoculated maize plants. However, the viral Coat Protein and Viral Protein genome-linked cistrons, and the green fluorescent protein signal were detected in both inoculated maize and in tobacco plants. Conclusions: We hypothesize that the ability of the clone obtained to infect tobacco is due to the use of the 35S promoter. This is the first monocot-infecting viral clone, that we are aware of, being able to be expressed in a dicot plant species.