Genetic structure and diversity of the common pistachio psylla, Agonoscena pistaciae Burckhardt & Lauterer, (Hemiptera: Aphalaridae) in Iran

Agonoscena pistaciae Burckhardt & Lauterer is a serious global economic pest of pistachio. Despite its economic importance, little is understood of its genetic diversity and population relatedness. We used two mitochondria' genes (COI and Cyt-b) and one nuclear sequence (ITS2) to investigate the genetic structure and diversity of 5 populations spanning the distribution of this pest in Iran. High levels of genetic diversity was found for all three genes due to the existence of two genetically divergent lineages. Haplotype network and phylogenetic analyses separated populations into two major clades, the central - southeastern and the northeastern dades. Because these lineages are genetically highly different with the genetic divergence of 4.57% - 4.99% and 3.61%-4.58% based on cytochrome c oxidase I and Cyt-b and 2.88% - 4.91% for nuclear 5.8S/ ITS2 sequences suggesting the possibility of existence of cryptic A. pistaciae species in Iran. Genetic structure analysis revealed that geographic adjacent populations share haplotypes, while distant populations exhibit distinct haplotypes, indicating geographic isolation and limited gene flow among populations. This finding is consistent with population pairwise F-ST analysis which found that most populations were genetically distinct. The high level of population genetic structuring is most probably related to dispersal capacity, life history variation and the geographic isolation among the populations.