Pretreatments, conditioned medium and co-culture increase the incidence of somatic embryogenesis of different Cichorium species

Abstract

Somatic embryogenesis (SE) in Cichorium involves dedifferentiation and redifferentiation of single cells and can be induced by specific in vitro culture conditions. We have tested the effect of various treatments on the incidence of SE (ISE) of an interspecific embryogenic hybrid (C. endivia x C. intybus) and of different commercial chicories (C. endivia and C. intybus) that are typically recalcitrant to SE in standard culture conditions. We found that the ISE of the hybrid is significantly increased by pretreatment of tissues by submersion in solutions of glycerol, abscisic acid, spermine, putrescine or of combinations of these compounds. Interestingly, the most efficient of these pretreatments also had an unexpectedly high effect on the ISE of the C. intybus cultivars. The ISE of the hybrid and of the commercial chicories were increased when explants were co-cultured with highly embryogenic chicory explants or when they were cultured in conditioned medium. These observations established that unidentified SE-promoting factors are released in the culture medium. HPLC analyses of secreted Arabino-Galactan Proteins (AGPs), which are known to stimulate SE, did not allow identifying a fraction containing differentially abundant AGP candidates. However, pointing to their role in promoting SE, we found that the hybrid had a drastically higher ISE when amino sugars and L-Proline, the putative precursors of secreted AGPs, were both added to the medium.

Flow cytometry and start codon targeted (SCoT) genetic fidelity assessment of regenerated plantlets in Tylophora indica (Burm.f.) Merrill

“…Several other researchers demonstrated auxins specifically 2,4-D’s efficacy (as most significant and strong PGR) in initiating somatic embryos in different plant species (Zhang et al 2007 ; Gulzar et al 2019 ). Since Daucus carrota, the incidence of somatic embryogenesis has been reported widely and histological and SEM evidence has been presented in many plant species (Couillerot et al 2012 ; Mujib et al 2013 ). The induced somatic embryos of Tylophora were later germinated and produced plants in BAP and GA 3 added medium.…”

The proof is in the bulb: glycerol influences key stages of lily development

“…Glycerol is a polyol that can be produced either through glycolysis or as a product of photosynthetic carbon fixation (Gerber et al ., ). The function(s) of glycerol in plant biology are still not totally clear, but previous studies have suggested roles for it in root development (Hu et al ., ), somatic embryogenesis (Bellettre et al ., ; Wu et al ., ; Couillerot et al ., ), abiotic stress response (Eastmond, ; Chen and Jiang, ) and the plant immune system (Chanda et al ., ; Li et al ., ).…”

The effects of proline on in vitro proliferation and propagation of doubled haploid sugar beet (Beta vulgaris)

“…Proline accumulation diminished reactive oxygen species (ROS) levels in wheat by increasing peroxidase and catalase levels, and thus protected it from salinity stress (Manjili et al, 2012). The addition of amino sugars and proline (17.36 mM) together to in vitro medium increased the incidence of somatic embryogenesis by 4-to 5-fold in Cichorium (Couillerot et al, 2012). In a comparative study on rice, proline supplementation (24.32 mM) to in vitro media increased scutellar callus fresh and dry weights more than any other supplemented amino acids did (Pazuki et al, 2015).…”