Reaction of sugarcane genotypes to strains of the sugarcane mosaic virus

Sugarcane crops are cultivated in nearly all tropical and sub-tropical regions worldwide andhave a prominent position in the agricultural scenario in Brazil. However, viral diseases can threaten the production of this important commodity leading to large production losses. In the present study, we evaluatedthe reaction of 20 sugarcane genotypes independently inoculated with two different strains of Sugarcane mosaic virus (SCMV) isolated from naturally infected sugarcane (SCMV-SGC) and maize (SCMV-MZ). The maize inbred line L19 was used as a control of susceptibility to the SCMV-MZ strain. Symptoms intensity was evaluated through a visual scale with three levels of severity: weak, intermediate, and intense. The viral infection was confirmed by PCR and DNA sequencing. We observed that, although both strains were able to infect sugarcane genotypes and the maize inbred line, SCMV-SGC was more aggressive, resulting in only four resistant genotypes: IN84-58 (S. spontaneum), RB855536, RB 928064, and SP71-6163. Thirteen genotypes were resistant to SCMV-MZ: IN84-58 (S.spontaneum), NA56-79, CB47-355,CB49-260, RB72454, RB855113, RB855536, RB867515, RB928064, SP70-1143, SP71-1406, SP71-6163, and SP81-3250. This is the first report showingSCMV strains capable of cross-infectingand causing mosaic in sugarcane and maize. Our data emphasize the importance of continuous monitoring and screening for virus resistantgenotypes to be used in breeding programs for the development of new resistant cultivars.