Small-Scale Bioreactor for Sterile Hydroponics and Hairy Roots: Metabolic Diversity and Salicylic Acid Exudation by Hairy Roots of Hyoscyamus niger

Abstract

The volume and complexity of commercial bioreactors for sterile hydroponics and hairy roots are too large for comparative analysis of many cultures. Here a small-scale bioreactor fabricated from standard glass materials and suitable for both airlift and bubble aeration mode is described. The performance of the bioreactor was tested by growing oilseed rape (Brassica napus L.) and rose plants (Rosa canina L.) in sterile hydroponics and by cultivating hairy roots of henbane (Hyoscyamus niger L.) and sesame (Hyoscyamus niger L.). Plants grown in hydroponics for up to six weeks did not show chloroses or necroses. Hairy roots grew faster or comparably fast in bioreactors as compared to shaking flasks. Root exudates of roses and exudates of hairy roots of henbane were subjected to targeted and nontargeted analysis by HPLC coupled with optical and mass spectrometric detectors. The diversity and concentration of hairy root exudates were higher in bioreactors than in shaking flasks. The composition of hairy root exudates of three accessions of H. niger did not match the genetic relatedness among the accessions. Hairy roots of Hyoscyamus niger exuded salicylic acid in amounts varying among plant accessions and between bioreactors and shaking flask cultures. Writing-original draft, P.K.; Writing-review and editing, P.K.

Lignans of Sesame (Sesamum indicum L.): A Comprehensive Review

“…Comparison of varieties regarding their lignan content in tissues other than seeds has only been reported in a single study. According to Kareem and coworkers [ 223 ], the differences in sesamin content of roots and hairy root among accessions and varieties of Sesamum indicum were larger than the differences among the sesamin content in seeds ( Table 4 ). Lignans other than sesamin were not detected in roots or hairy roots [ 223 ].…”

“…Culturing conditions exert tremendous effect on the metabolic productivity of tissues and cells. For instance, the same hairy root culture of S. indicum accumulated certain metabolites in a bioreactor, while these metabolites were essentially missing when the roots were grown in flasks [ 223 ].…”

“…Hairy roots of L. austriacum accumulated 16.9 mg/g dry weight of justicidin B while cell cultures accumulated just 6.7 mg/g [ 452 ]. Ogasawara and coworkers reported that hairy roots from S. indicum accumulated sesamin and sesamolin [ 226 ], but Kareem found only sesamin in hairy root cultures of 25 accessions of S. indicum [ 223 ].…”

“…The content of lariciresinol in hairy roots of Chinese medical plant Isatis indigoticas increased from 24 mg/g to 96 mg/g by overexpression of a single gene of the lignan pathway (the gene IiC3H encoding P450 hydroxylase; [ 409 ]). Because hairy root cultures of S. indicum can be generated easily (e.g., [ 223 , 456 ]) and many genes of the lignan pathway have been characterized (see Section 4.1 ), genetically modified hairy roots appear to be a feasible approach towards engineering lignan synthesis in sesame.…”

Hairy roots: An untapped potential for production of plant products

“…hairy root tissue culture to transition out of the lab into industrial production of products, one must be able to grow them at larger scales than a shake flask. There are many excellent reviews discussing scale up of hairy roots (Stiles and Liu, 2013;Jeong and Park, 2017;Mehrotra et al, 2018;Kareem et al, 2019;Valdiani et al, 2019). Here we will highlight the various bioreactor design configurations.…”