Genetic diversity in populations of Nezara viridula (Hemiptera: Pentatomidae) based on mitochondrial DNA sequences

BEATRIZ A. GARCIA; ALICIA R. PÉREZ DE ROSAS

Buenos Aires

Jornada; XX Jornadas Anuales de la Sociedad Argentina de Biología, XVII Jornadas de la Sociedad Uruguaya de Biociencias, Segundas Jornadas Rioplatenses de Biología; 2018

Sociedad Argentina de Biología y Sociedad Uruguaya de Biociencias

Nezara viridula is a cosmopolitan species that produce important economic damages on different crops. The analysis of genetic variability can provide bases for understanding the dynamic and evolution of natural populations of this insect pest. Previous analyses based on cytochrome oxidase I (COI) gene sequences of N. viridula from different localities of Argentina, revealed limited levels of variability. In order to identify potentially useful fragments for the study of the genetic variability in populations of N. viridula, mitochondrial sequences corresponding to the subunit 5 of NADH dehydrogenase (ND5) gene and the control region were analyzed in specimens from different Argentinian populations. The comparative analysis of a fragment of 884 bp of the ND5 gene from 23 specimens belonging to three localities, revealed 6 haplotypes determined by 6 variable sites. The total nucleotide diversity was 0.00108 and 0.00184 according to the estimators π and θw, respectively. The mean value of haplotypic diversity (Hd) was 0.680. The moderate levels of genetic differentiation observed among populations and the presence of exclusive haplotypes suggest that gene exchange among populations would not be enough to disperse these haplotypes. On the other hand, a fragment of 1785 bp of the control region of 69 individuals from seven localities was analyzed. The DNA sequence comparison revealed 60 haplotypes determined by 108 variable sites. The total nucleotide diversity was 0.00426 and 0.0126 for π and θw, respectively, and the mean value of Hd was 0.990. Neutrality tests suggested that the majority of the populations would have experienced expansion events. No significant association was detected between geographic distance and genetic differentiation among the sites sampled (Mantel r = -0.139, P = 0.742). This pattern suggests restricted gene flow among sampling sites, where haplotypes frequencies could drift independently without relation to the geographic distances separating them. It is probable that during the population reductions caused by the insecticides used to control this agricultural pest, the genetic drift would have play a rol in the differentiation and structuring of the populations independent of geographical distance. The results obtained indicated that ND5 and control region sequences would be useful to analyze the dynamic and evolution of N. viridula populations.