No abstract

Maruca vitrata is one of the primary biotic constraints for pigeon pea production in India. The present study assessed the genetic variation and population structure of M. vitrata from diverse agro-ecologies in India using the mitochondrial cytochrome c oxidase I gene. A low number of segregating sites (10), haplotypes (13), nucleotide diversity (0.00136), and overall mean genetic distance (0.0013) were observed among the populations. The negative values of the neutrality tests and unimodal mismatch distribution supported its demographic expansion in the country. The analysis of molecular variance (AMOVA) revealed that the variation among populations or groups was only 13.91%, and the geographical distance did not significantly contribute to the genetic differentiation (R2 = 0.0024, p = 0.280). The clustering of haplotypes was also independent of the geographical location. Overall, our results suggest the existence of low genetic variation and high gene flow among populations of M. vitrata in India.

Maruca vitrata (Fabricius) is an invasive insect pest capable of causing enormous economic losses to a broad spectrum of leguminous crops. Microsatellites are valuable molecular markers for population genetic studies; however, an inadequate number of M. vitrata microsatellite loci are available to carry out population association studies. Thus, we utilized this insect’s public domain databases for mining expressed sequence tags (EST)-derived microsatellite markers. In total, 234 microsatellite markers were identified from 10053 unigenes. We discovered that trinucleotide repeats were the most predominant microsatellite motifs (61.53%), followed by dinucleotide repeats (23.50%) and tetranucleotide repeats (14.95%). Based on the analysis, twenty-five markers were selected for validation in M. vitrata populations collected from various regions of India. The number of alleles (Na), observed heterozygosity (Ho), and expected heterozygosity (He) ranged from 2 to 5; 0.00 to 0.80; and 0.10 to 0.69, respectively. The polymorphic loci showed polymorphism information content (PIC), ranging from 0.09 to 0.72. Based on the genetic distance matrix, the unrooted neighbor-joining dendrogram differentiated the selected populations into two discrete groups. The SSR markers developed and validated in this study will be helpful in population-level investigations of M. vitrata to understand the gene flow, demography, dispersal patterns, biotype differentiation, and host dynamics.