Cultivation of chicory plants for various applications, such as utilisation of the root biomass for preparation of a coffee adjuvant, utilisation as a vegetable and, recently, utility of the plants for important phytochemicals, has received global attention. Chicory is widely grown in countries of different geographical locations owing to the economic importance of this crop. This review addresses cultivation, utility, phytochemical studies and pharmacological aspects, with an emphasis on biotechnological developments in recent years and safety evaluation of genetically modified chicory crops. These aspects are dealt with in detail to bring out the current status and future prospects of cultivation and utility of this economically important crop.

Cichorium intybus L – cultivation, processing, utility, value addition and biotechnology, with an emphasis on current status and future prospects

Related or distant species of cultivated cs are a large pool of many desirable genes. Gene transfer from these species through conventional breeding is difficult owing to post- and pre-zygotic sexual incompatibilities. Somatic hybridization via protoplast fusion is a possible alternative for gene transfer from these species to cultivated crops. Since the early days of somatic hybridization many intergeneric somatic hybrids have been developed through symmetric fusion, asymmetric fusion and microfusion. Somatic hybrids are mainly selected by using markers such as specific media or fusion parents with special features, biochemical mutants, antibiotic resistance and complementation strategy. The hybridity of the regenerants is determined based on morphological, cytological and molecular analysis. The inheritance patterns of nuclear and cytoplasmic genomes in the somatic hybrids are diverse. Nuclear DNA from both fusion parents co-exists congruously in some hybrids with translocation and rearrangement of chromosomes, but spontaneous elimination of chromosomes from either or both fusion parents has been observed very often. In asymmetric fusion, chromosome elimination is an important issue that is a complicated process influenced by many factors, such as irradiation dose, phylogenetic relatedness, ploidy level of fusion parent and regenerants. As for chloroplast genome, uniparental segregation is mainly detected, though co-existence is also reported in some cases. The mitochondrial genome, in contrast to chloroplast, undergoes recombination and very frequent rearrangements. Somatic cell fusion has potential applications for crop genetic improvement by overcoming sexual incompatibility or reproductive barriers, and by realizing novel combinations of nuclear and/or cytoplasmic genomes.

Intergeneric somatic hybridization and its application to crop genetic improvement

The seed is the primary organ for the perpetuation of germplasm and propagation in all flowering plants. It contains the embryo which develops from the zygote following the fertilization of the egg cell by one of the male gametes. Gene recombination during the formation, as well as the fusion, of the gametes plays a critical role in the evolution of the angiosperms. During its development the embryo is nourished by the endosperm, which itself is formed as a result of the fusion of the second male gamete with two nuclei (in most of the angiosperms) of the central cell of the embryo sac. During the course of evolution many species have developed special means of propagation to overcome physical, environmental and genetic factors that prevent flowering and seed formation. These include the formation of perennial structures such as tubers, rhizomes, bulbs, stolons, etc (see Sharma and Thorpe, this volume). An advanced form of perennation is found in many apomictic species which produce embryos from unfertilized gametic or somatic cells. Like the zygotic embryos, the apomictic embryos develop within the seed and are protected and dispersed like natural seed. Apomictic embryos of all genotypes — irrespective of heterozygosity — developing from unreduced and unfertilized somatic or gametic cells (agamospermy, adventive embryony, apospory, diplospory) breed true and give rise to clonal populations. Apomixis is known to be under genetic control, but environmental conditions such as temperature and photoperiod may also promote a switch from sexual to apomictic development [1,2].

https://link.springer.com/content/pdf/10.1007/978-94-011-0485-2_10

Somatic Embryogenesis in Herbaceous Dicots

A consensus genetic map for chicory (2n = 2x = 18) was obtained after the integration of molecular marker data of two industrial chicory progenies (K28K59, Rubis118) and one witloof chicory progeny (BR). As a limited number of co-dominant markers was available at the beginning of this work, three different microsatellite-enriched libraries were produced from genomic DNA, resulting in 420, 719 and 1,251 sequences, respectively. The level of informative Simple Sequence Repeat (SSR) sequences from the three libraries ranged from 28 to 40%, thus defining a set of 730 SSR markers available for polymorphism screening. A subset of 81 Sequence-Tagged Sites (STS) developed from EST, cDNA, genes, and non-coding sequences was screened through Single Strand Conformational Polymorphism (SSCP) analysis, leading to 46 polymorphic loci integrated in the genetic maps. Markers were grouped and ordered on 9 homologous Linkage Groups (LG) for each of the three maps: 274 markers in K28K59, 282 markers in Rubis118, 178 markers in BR. Co-linear regions between maps were identified through 193 ‘bridge’ markers that allowed the integration of the 9 homologous LG in a consensus map containing 472 markers and covering 878 cM. Comparison across maps revealed the presence of 4 conserved regions with significant distorted markers, also defined as Segregation Distortion Regions (SDR), affected by gametic or zygotic selection factors. Marker distribution was not always uniform; 6 LG possessed homologous clustered regions in all maps. The consensus map could be the starting point for the identification and the cloning of major genes and QTL in fundamental and applied genetic areas in chicory.

Development of SSR markers and construction of a consensus genetic map for chicory (Cichorium intybus L.)

Chicory and Endive

Male-sterile chicory plants were obtained by fusion of chicory mesophyll protoplasts and hypocotyl protoplasts derived from male-sterile sunflower plants. The protoplasts of both species were fused by the PEG method and the products were selected manually and cultivated at very low density in a liquid medium. Three to twenty percent of the heterokaryocytes divided and evolved into microcalli, then into calli where budding could be induced. The mitochondrial genome of ten male-sterile or totally sterile plants was studied. Restriction endonuclease profiles of mitochondrial DNA and molecular hybridization with specific genes of the mitochondrial genome used as probes indicated that mitochondrial DNA rearrangement had occurred between sunflower and chicory and the intensity of the rearrangements correlated with the degree of sterility of the different plants.

Male-sterile chicory cybrids obtained by intergeneric protoplast fusion.

Fusions of chicory leaf protoplasts were realized in order to obtain a higher number of tetraploid plants compared to the traditional doubling techniques with colchicine. Thanks to the fusion technique, using a mixture of PEG, DMSO and a solution of CaCl2 (pH 10.5), 25% tetraploid (2n=36) plants were obtained. Among the 167 regenerated plants, only one aneuploid of a near tetraploid level (2n=33) was identified.

The induction of tetraploidy in chicory (Cichorium intybus L. var. Magdebourg) by protoplast fusion

Somatic embryos and adult plants were regenerated from mesophyll protoplasts of a clone of chicory ‘474’ (Cichorium intybus L. x Cichorium endivia L.). Embryos were obtained in three different ways:


- plating of 7-day-old protoplast cultures on PM-3 solid induction medium with 2.5 μM 2-isopentenyladenine (2-iP) and 0.5 μM naphthaleneacetic acid (NAA);


- transfer of 1–2 mm microcolonies into liquid M-17 induction medium with 2.5 μM (2-iP) and 0.1 μM (NAA);


- transfer of well-established protoplast-derived calluses onto M-17.

https://link.springer.com/content/pdf/10.1007/BF00033612.pdf

Somatic embryogenesis and plant regeneration from protoplasts of Cichorium intybus L. x Cichorium endivia L.

Conditions have been established for efficient plant regeneration from protoplasts of the cultivar Pevele of Cichorium intybus L var Magdeburg. In order to increase the yield of protoplasts which are able to undergo cell divisions during the first week of culture, protoplasts of Magdeburg chicory were cultured in a Murashige and Skoog (1962) modified medium containing 2 mg/l ANA, 1 mg/l BA, 10 g/l sucrose, a mixture of glutamine-KNO 3 as nitrogen source and were placed at a temperature of 30°C (...)

/pdf/some-factors-related-to-protoplast-culture-and-plant-17ivuqw5bf.pdf

Some factors related to protoplast culture and plant regeneration from leaf mesophyll protoplasts of Magdeburg chicory (Cichorium intybus L var Magdeburg)

J. Dubois

Papers

Male-sterile chicory cybrids obtained by intergeneric protoplast fusion.

The induction of tetraploidy in chicory (Cichorium intybus L. var. Magdebourg) by protoplast fusion

Somatic embryogenesis and plant regeneration from protoplasts of Cichorium intybus L. x Cichorium endivia L.

Some factors related to protoplast culture and plant regeneration from leaf mesophyll protoplasts of Magdeburg chicory (Cichorium intybus L var Magdeburg)