Estudio de la variabilidad de la región its2 en poblaciones de Tetranychus urticae Koch en el cultivo de taxo ( Passiflora tripartita)

Abstract

Tetranychus urticae, also known as the two-spotted mite, is distributed worldwide, being found in different host plant species, including strawberry, blackberry, white carrot. In this study, the genetic variability of the ITS2 region was determined in populations of T. urticae in the culture of Passiflora tripartita (banana passionfruit) in different localities of the province of Tungurahua. Samples of T. urticae individuals were taken from infested banana passionfruit leaves in three localities: Ambato (AM), Cevallos (CE) and Tisaleo (TI). Subsequently, leaf samples were taken to the Molecular Biology laboratory of the Faculty of Agricultural Sciences of the Technical University of Ambato in order to amplify the ITS2 fragment using PCR techniques. After sequencing, 545 base pairs (bp) it was obtained for T (Thymine) with 34.50% (AM), 35.05% (CE) and 34.13% (TI), for A (Adenine) with 29, 54% (AM), 29.72% (CE) and 28.99% (TI). Similarly, the percentage indices for C (Cytosine) with 17.25%, (AM), 16.88% (CE), 17.43% (TI) and for G (Guanine) with 18.17% (AM), 18.17% (CE) and 17.61% (TI). In the sequencing, 13 substitutions were presented in the nitrogenous bases for the three localities, since the TI-CE relationship showed 8 substitutions with 98.17% similarity and with a divergence of 1.83%, while TI-AM showed 13 substitutions. with a similarity of 99.45% and finally CE-AM presented 5 substitutions with a percentage of similarity of 99.82%. The similarity values between the populations of T. urticae studied showed that there is little differentiation from the molecular point of view, which suggests that little variability has occurred between populations.