FIRST REPORT OF POTATO LEAF ROLL VIRUS IN TREE TOMATO IN ECUADOR

Tree tomato (Solanum betaceum), family Solanaceae, is an economically important fruit crop in Ecuador, where it is grown on 5,964 ha with a yearly production of 14,695 tonnes (General System Coordination of National Information, MAGAP, 2012). In September 2015, different commercial tree tomato fields in the Pichincha province showed mosaic and curling of the leaves, as well as stunted growth. Based on symptomatology, infection by Potato leaf roll virus (PLRV, genus Polerovirus, family Luteoviridae) was suspected. The presence of this virus was ascertained in five of the eight tree tomato samples screened by DAS-ELISA with a commecial kit (Agdia, USA) and by RT-PCR using PLRV primers (Singh et al., 1995). The resulting (ca. 330 bp) amplicons were purified, custom-sequenced (Marcrogen, South Korea) and the sequences were deposited in GenBank as accession Nos. KU258499-KU258503. Sequence analysis (BioEdit v. 27 7.05) showed a maximum identity of 99.6% and 100% at the nucleotide and amino acid levels, respectively. A phylogenetic tree constructed using MEGA version 4.1 revealed two clades with the Ecuadorian CMV isolates clustered in clade 1 together with isolates from Colombia (JF939832 and HQ396183), Peru (AF453392), Cuba (S77421), India (AF539791), China (KC456052 and KR051194), New Zealand (GU002343) and Australia (D13953), whereas isolates from Argentina (AF220151), Germany (JQ346191), and the USA (KP090166) formed clade 2. Isolates from Iran (EU450876) and Brazil (AF453406) gave rise to clade 3. Based on our findings, the infected crop was eliminated to eradicate the infection. To the best of our knowledge, this is the first report of PLRV on tree tomato in Ecuador.