Genetic Diversity of African Mistletoe (<i>Loranthus micranthus</i> Linn.) Accessions from Selected Plant Hosts Using Internal Transcribed Spacer (<i>ITS</i>) Gene

Abstract

African mistletoe ( Loranthus micranthus  Linn.) is a parasitic plant which has shown to contain biologically active agents that have disease curing effects on humans. The present study aimed at evaluating the genetic diversity of  L. micranthus  accessions established on selected plant host based on  ITS  gene. 9 samples were selected for PCR amplification and sequencing of the  its 1 and  its 4 regions. The results revealed 104 and 89 polymorphic sites for  its1  and  its4  respectively. Haplotype diversity of 0.971+0.064 and nucleotide diversity 0.174+0.071 were recorded in  its1  while haplotype diversity of 0.917+0.092 and nucleotide diversity of 0.231+0.027 were recorded in  its4 . Phylogenetic analysis grouped the samples into 2 clusters based on the  its  regions. A high genetic distance (0.597) for  its1  was obtained between samples from Pepper fruit and samples obtained from other host trees (African apple, Avocado and Monkey kola) while a low genetic distance (0.000) was obtained between  C. apiculatum  (LMV9) and African apple host (LMV4). The highest genetic distance (0.827) for  its4  was obtained between  C. apiculatum  (LMV9) and African apple host (LMV4) while the lowest genetic distance (0.000) was obtained between Rubber hosts (LMV1, LMV2) and Pepper fruit host (LMV8). The results revealed some genetic diversity amongst the mistletoe grown on different hosts suggesting that host trees and geographical location might contribute to genetic diversity. It also showed that  its1  and  4  regions differ in their variation discernment pattern in mistletoe and similar studies can be conducted in larger populations to accurately link genetic similarity/variation to host specificity and geographical origins.