Levantamento e estudo das espécies de badnavirus que infectam bananeiras no Brasil

Abstract

Banana streak virus (BSV) is one of the main virus that affect bananas in Brazil. The symptoms of the disease are variable, presenting from chlorotic streaks on the foliar limb to the abnormal development of banana bunches and death, beginning at the point of growth. Due to the genomic heterogeneity of the BSV isolates and to the fact that it presents the property of incorporating to the banana genome, the use of serologic and molecular techniques for its detection not always presents the desired efficiency, being of great importance to analyze the variability of the isolated of this virus in Brazil in order for prevention and diagnosis measures to be well established for the country. In this context, we aimed at analyzing the genomes of isolates collected in different producing regions of the country, based on its enzyme restriction profile and on the sequence of the RT/RNase H. The viral dsDNA was obtained with the extraction of the total DNA of the plants, from the foliar tissue and amplified using the Illustra TempliPhi 100 Amplification Kit (GE Healthcare, Buckinghamshire, United Kingdom). The conserved region of the Badnavirus used for differentiating species was amplified by the PCR, purified and sent for sequencing. The genomic DNA obtained by the RCA reaction was submitted to cleavage with the following enzymes: EcoRI, KpnI, PstI, SacI, XbaI, XhoI. The analyses of the 540pbs fragments amplified by PCR, of the 13 BSV isolates based on the ICTV variant classification criteria, allowed the identification of 2 BSV variants, with 10 being classified as Banana streak Mysore virus, 1 as Banana OL virus, 2 presented high similarity to Musa acuminata (genotype AA). The analysis of the restriction profile was not consistent with the data found in literature, not being adequate for classifying the species, while the sequence analysis of the RT/RNase H region allowed a safe classification inside the standards already established for the Badnavirus.