Neem Tissue Culture

Abstract

The neem tree is a well-known source of metabolites used in the production of bio-pesticides and medicines. To understand the nature and composition of these metabolites in various tissues, in vitro calli were established. Calli from leaves, petals, cambium, and endosperm of the neem tree were successfully induced. The callusing response from petal and endosperm explants were fast demonstrating callus growth in three days and seven days, respectively. Cambium explant showed slow response taking about thirty days for callus formation. Regenerated plantlets were developed from endosperm explant, a triploid tissue, which contained the highest metabolites among selected explants. The concentration of important metabolites including Azadirachtin, Nimbin, Salanin, Azadiradione, and Epoxy/Hydroxy-azadiradione in the different explants, respective calli and regenerated plants were estimated using Ultrahigh Performance Liquid Chromatography-Mass Spectrometry (UHPLC-MS) method. Interestingly, the leaves of regenerated plant derived from endosperm callus showed over hundred-fold higher Azadirachtin content as compared to leaves of the mature tree. Triploidy of the endosperm derived regenerated plant was confirmed using flow cytometry. Using leaves from these tissue culture-derived triploid plants could be a non-destructive source for commercial extraction of metabolites and producing bio-pesticides.