Phylogeny of Neem and Related Species in the Meliaceae Family

Abstract

Neem belongs to Meleaceae family also called Mahogany family. It includes 50 genera and 1400 species. In India, it is represented by 20 genera and 70 species. However, the chemical composition of these species has high variability. This study was aimed at understanding the genetic distance of neem tree in relation to other family members (Azadirachta indica, Amoora lawii, Dysoxylum malabaricum, Khaaya, Melia Azadirachta, Melia dubia, Swietenia macrophylla, Sweitenia mahogany, Soymida fabrifuga, Toona ciliate, Walsuria trifoliate). Additionally, species were also analysed for Azadirachtin concentration in the leaf with the aim to find clues about the evolution of Azadirachtin pathway and the family members who share it. Neem tree synthesises a large number of unique bioactive compounds. Chemical synthesis of many of these compounds has been tried in the laboratory; complex synthesis process and molecular complexity involved makes the process not a viable option for commercial production (Veitch et al. 2008). However, to increase the natural production or engineering new production methods require a deeper understanding of the synthesis process and also the genes/enzymes involved in their biosynthesis. Sequencing of neem genome is aimed at elucidating all the genes that are present in neem and understanding pathways of synthesis for many of the compounds that are produced by neem tree. Studying neem genome will also be useful in understanding the mechanism of resistance to abiotic stress.