ANÁLISE COMPUTACIONAL: DIVERSIDADE GENÉTICA DE TOMATO CHLOROSIS VIRUS INFECTANDO TOMATEIRO

Abstract

Tomato chlorosis virus (ToCV) (genus Crinivirius, family Closteroviridae) infects tomato (Solanum lycopersicum) crops in Brazil and in other countries, reducing productivity. Visible symptoms are chlorotic spots and leaf necrosis. Transmission occurs by Bemisia tabaci, B. argentifolii, Trialeurodes vaporariorum and T. abutilonea flies, in a semipersistent way ToCV has bipartite genome, RNA1 (4 ORF) (open reading frames) and RNA2 (9 ORF). The aim of this study was to adapt the use of bioinformatics tools using genetic sequences from the RdRp, P22 and Hsp70h ORFs of ToCV isolates to determine genetic variability and obtain phylogenetic trees. Sequences were obtained from 16 isolates from tomato leaf samples collected in Brazil, in Brasília (Federal District, n = 7) and Goianápolis (Goiás, n = 9), with sequences from 43 isolates obtained from the GenBank database. Four populations (Brazil n = 17, China n = 16, South Korea n = 9 and Spain n = 15) were analyzed using methods (Muscle, ModelTest, Bayesian Inference and SLAC) and bioinformatics tools (Mega, Paup, Figtree, DNAsp and DataMonkey) to obtain descriptors of genetic variability and phylogenetic trees. The results indicate that among the genomic regions of the analyzed isolates, RdRp presents higher genetic differentiation and P22 shows higher nucleotide diversity and selection pressure, compared to the other ORFs analyzed. The analyzed Brazilian isolates showed lower nucleotide diversity and higher genetic neutrality when compared to the other analyzed populations. The analyzed Brazilian isolates present a possible evolutionary proximity with some South Korean isolates.