First report of tomato severe rugose virus in eggplant
Begomoviruses are transmitted by the whitefly Bemisia tabaci and cause important diseases in solanaceous crops in Brazil (Inoue-Nagata et al. 2016). During 2014–2017, eggplants (Solanum melongena) exhibiting chlorosis and mild mottle were found in five fields of São Paulo State, Brazil. Total DNA was extracted (Dellaporta et al. 1983) from randomly collected symptomatic and non-symptomatic eggplants, followed by rolling circle amplification (RCA) (TempliPhi DNA Amplification kit, GE Healthcare, USA) and polymerase-chain reaction (PCR) using the degenerate begomovirus DNA-A component primers PAR1c496/PAL1v1978 (Rojas et al. 1993). Forty-one symptomatic plants were positive for begomovirus infection by RCA-PCR, whereas the non-symptomatic plants were negative. Eight randomly chosen amplicons were directly sequenced and the partial sequences (∼1.200 bp) had 95–99% nucleotide sequence identity to the corresponding sequence of the begomovirus tomato severe rugose virus (ToSRV). The complete nucleotide sequence of the DNA-A component of one sample was determined by primer walking with PCR-RCA product as template (2595 bp) (GenBank accession number KY781196). This complete DNA-A had 97% identity with an isolate of ToSRV from pepper (GenBank accession number J824808). A fragment of the DNA-B component from the same eggplant isolate was also amplified by PCR with primer pair PCRc1/PBL1v2040 (Rojas et al. 1993), and the sequence of 550 bp had 95% identity with the DNA-B sequence of ToSRV (GenBank accession number KC7066271). Additionally, virus-free whiteflies were confined in small individual cages containing a ToSRV-infected eggplant, for an acquisition access period of 24 h, then 20 insects per plant were transferred to seedlings of tomato, sweet pepper, Nicotiana benthamiana, and eggplant (cultivars ‘Napoli’, ‘Napolitana’ and ‘Roma’) for an inoculation access period of 48 h. ToSRV infection was confirmed in all tested plants 30 days post-transmission. Following insect transmission, infected eggplants and tomato plants exhibited mild foliar mottling, whereas all other plants were non-symptomatic. To our knowledge, this is the first report of ToSRV infecting eggplant in Brazil.
MFM is a FAPESP post-doctoral fellow. LFMW is a recipient of a CAPES Master fellowship. RKS, MAP, JAMR and AKIN hold CNPq research fellowships. This research was supported by a grant from FAPESP Project 2012/51772-4