Phenotypic, molecular and biochemical evaluation of somatic hybrids between Solanum tuberosum and S. bulbocastanum

Abstract

Somatic hybridization has been frequently used to overcome sexual incompatibility between potato and its secondary germplasm. The primary objective of this study was to produce and evaluate somatic hybrids of Solanum tuberosum (Stub) and S. bulbocastanum (Sblb) for breeding purposes. In 2007, 23 somatic hybrids were produced using an electrofusion of mesophyll protoplasts of diploid (2n = 2x = 24) potato line StubDH165 and S. bulbocastanum PI24351 (Sblb66). Phenotype of somatic hybrids in field conditions were evaluated, together with constitution and stability of 30 nuclear (ncSSR) and 27 cytoplasmic (cpSSR) microsatellite markers and content of main glycoalkaloids. All somatic hybrids had very high field resistance against late blight, but the plants were infertile: the viability of pollen grains insignificantly varied between 0.58 and 8.97%. A significant somaclonal variation was observed in terms of the morphology of plants, the date of emergence, the quantity of harvested tubers, the content of glycoalkaloids in foliage, and nuclear microsatellite markers (ncSSR). The analysis of ncSSR identified five distinct genotypes of hybrids partly associated with phenotype variations. The process of somatic hybridization with regeneration of shoots was identified as the most likely source of somaclonal variation because the ncSSR genotypes of hybrids, which were maintained in vitro, remained stable for more than 10 years. The infertile somatic hybrids have no practical breeding potential, but they are considered very suitable for advanced studies of the differential expression of genes in the pathways linked to dormancy of tubers and synthesis of glycoalkaloids.

Phytochemical Profile and Selective Cytotoxic Activity of a Solanum bulbocastanum Dun. Methanolic Extract on Breast Cancer Cells

“…The methanolic extract of S. bulbocastanum leaves obtained by the UAE technique did not contain any Solanaceae -specific glycoalkaloids, such as α-chaconine and α-solanine, which are known to be part of the phytochemical profile of a wide variety of wild Solanum species. This data is consistent with previous findings, which demonstrated that S. bulbocastanum in particular does not contain such compounds [ 21 ] or that if present in its leaves, these metabolites are found in very low quantities [ 19 , 20 , 36 ]. In any case, the presence of such glycoalkaloids in the final extract also depends on the extraction method and solvent used, and thus these results do not exclude the possibility that these Solanaceae -specific glycoalkaloids are found in the leaves of S. bulbocastanum.…”

“…Furthermore, in terms of its phytochemical profile, S. bulbocastanum was evaluated only for its glycoalkaloid content and the data available in this regard is somewhat contradictory. While some studies report the presence of both α-chaconine and α-solanine in this species at low concentrations [ 19 , 20 ], others were not able to identify these Solanaceae -specific alkaloids in S. bulbocastanum [ 21 ]. Therefore, considering the lack of knowledge regarding this species and its putative antitumor activity based on results obtained with its phylogenetically close relatives, S. bulbocastanum might have an impact in cancer management, at least in the prevention of cancer due to its usage in potato breeding programs.…”

Homoeologous Chromosome Pairing and Alien Introgression in Backcrossing Progenies Derived from Hybrids Solanum tuberosum (+) Mexican 2x (1 EBN) B-Genome Potato Species

“…To increase the efficiency of interspecific hybridization for broadening the genetic diversity of S. tuberosum (tbr), protoplast fusion techniques have been frequently used to overcome the interspecific incompatibility between the common potato and the diploid Bgenome Mexican potato species: S. bulbocastanum (blb) [9][10][11][12][13][14][15][16][17], S. pinnatisectum (pnt) [12,13,[18][19][20][21][22][23][24][25][26][27][28], and S. tarnii (trn) [29]; S. cardiophyllum (cph) [23,30,31] and S. x michoacanum (Bitter.) Rydb.…”

“…In most cases, the interspecific somatic hybrids between the potato and diploid B-genome Mexican species had a low level of fertility or were sterile, were characterized by poor agronomic characters, and the degree of their disease and/or pest resistance was lower than in the parental clones of wild species [12,15,17,25,32,34,35]. These undesirable characteristics could be due to somaclonal variation induced during protoplast isolation and fusion and the regeneration of hybrid plants [17,36,37]. Thus, cytogenetic instability as mitotic and meiotic irregularities, aneuploidy, and mixoploidy, were detected using cytological methods in the somatic hybrids tbr(+)blb [12,38,39] and tbr(+)pnt [23].…”

“…Thus, cytogenetic instability as mitotic and meiotic irregularities, aneuploidy, and mixoploidy, were detected using cytological methods in the somatic hybrids tbr(+)blb [12,38,39] and tbr(+)pnt [23]. The elimination of parental alleles and markers and genome structural variation were demonstrated in tbr(+)blb, tbr(+)pnt, and tbr(+)mch somatic hybrids using species-specific RAPD [38,40], RFLP [40], ISSR [15,27], and SSR [17] markers; DArT analysis [33]; and genome sequence analysis [28].…”