studies of Rhizoctonia solani, methyl jasmonate, and salicylic acid were conducted for shikalkin production in A. euchroma callus. For the regeneration of callus, various types of explants (leaf, collar, and root) were inoculated onto LS medium. Maximum shikalkin biosynthesis was stimulated by White medium supplementing with indole-3-acetic acid (IAA) and kinetin. R. solani increased the pigment production by sevenfold higher than control. It is suggested that in polysaccharides of the fungal cells, a cascade of signaling induced the expression of genes those involved in the biosynthesis of shikalkin (Arghavani et al. 2015). Arnebia species in vitro culture research has been widely dedicated to improving shikonin production by application of various strategies, among them changing medium composition, addition of different elicitors, and various in situ extraction methods (Fu and Lu 1999; Ge et al. 2006; Chaudhury and Pal 2010; Kumar et al. 2011; Malik et al. 2011; Shekhawat and Shekhawat 2011).
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