Enhancement of Shikalkin Production in Arnebia euchroma Callus by a Fungal Elicitor, Rhizoctonia solani

Abstract

Background: There is a growing demand for mass production of shikalkin (a natural pigment consisted of shikonin and alkannin) due to its increasing applications in cosmetics, pharmaceutical and nutrition industries. The root of Iranian Arnebia euchroma produces shikalkin. The promising capability of this plant for shikalkin production has already been demonstrated in cell culture studies. Objectives: Elicitation effect of Rhizoctonia solani (R. solani) in comparison with the effects of Cu 2+ , methyl jasmonate (MJ), and salicylic acid (SA) on the shikalkin production was investigated in A. euchroma callus. Materials and Methods:The calli from different origins (leaf, collar and root) were proliferated on a modified LinsmaierSkoog (mLS) medium and were subsequently transferred onto the pigment production medium containing various amounts of the desirable elicitor. Observations were quantified and the pigment production was precisely measured spectrophotometrically. Results: Pigment biosynthesis was induced on White medium containing IAA (1 μM) and kinetin (10 μM) in dark at 25°C. Use of R. solani increased the pigment production by 7 fold greater than normal White medium. Cu 2+ only doubled the shikalkin production. MJ and SA showed enhancing effects comparable to that of Cu 2+ . Discussions: It is assumed that upon binding of the polysaccharides of the fungal cells to the plant cell surface, a cascade of signaling is initiated that led to expression of genes involving in the biosynthesis of shikalkin.

Metabolite Production in Alkanna tinctoria Links Plant Development with the Recruitment of Individual Members of Microbiome Thriving at the Root-Soil Interface

“…Similarly, Paraburkholderia phytofirmans strain PsJN is a well-known plant colonizer that shows hormone and ACC deaminase production and is known to elicit plant responses ( 38 , 39 ). Fungal elicitors, which enhance A/S production, have been previously described for the Boraginaceae species Arnebia euchroma ( 40 , 41 ). In our study we found a moderate positive correlation between the root fungal rASV41 ( Penicillium jensenii ) and higher A/S levels (HPLC, Fig.…”

Ammonium/Nitrate Ratio Affects the Growth and Shikonin Accumulation in <em>Arnebia euchroma</em>

“…Previous studies demonstrated that different exogenous hormones have various effects on shikonin accumulation. For instance, GA [29] and ABA have significantly negative impacts on shikonin biosynthesis, while MeJA and SA [12,16,30,31]can effectively promote it. In our study, the content of endogenous GA4 in AEHR under 30% NH4 + treatment did not change significantly within 48h, suggesting that GA may not be involved in the regulation process of NH4 + toxicity in AEHR.…”

“…They found the addition of exogenous SA caused a decreased activity of PHB geranyltransferase, one of the key regulatory enzymes in shikonin biosynthesis [30]. In another study, Arghavani et al reported higher enhancing effects of SA compared to JA [12]. There is no report on the relationship between the endogenous content of SA and shikonin production.…”

“…MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions, or products referred to in the content. medium compositions, abiotic/biotic elicitors, and signal transduction molecules on shikonin synthesis of callus, suspension cells, and hairy root cultures have been widely studied [9,[11][12][13][14][15][16]. However, the effects of nitrogen on the shikonin synthesis remains elusive.…”

The Ammonium/Nitrate Ratio Affects the Growth and Shikonin Accumulation in Arnebia euchroma

“…After that, a medium without NH 4 + was widely used for shikonin production in vitro using cell, tissue, and organ cultures of L. erythrorhizon, A. euchroma, and Onosma paniculatum. To optimize the culture conditions, the effects of various medium compositions, abiotic/biotic elicitors, and signal transduction molecules on shikonin synthesis in callus, cell suspension, and hairy root cultures have been widely studied [9,[11][12][13][14][15][16]. However, the effects of nitrogen on shikonin synthesis remain elusive.…”