Electrofusion of protoplasts from Solanum tuberosum, S. nigrum and S. bulbocastanum

Abstract

Leaf protoplasts of two wild species, Solanum nigrum var. gigantea (S. ngr gig) and S. bulbocastanum Dun. (S. blb), were electrofused with leaf protoplasts of two diploid potato clones, H-8105 and ZEL-1136, respectively, in order to confer the late blight-resistance from the wild species to the cultivated potato. The S. ngr gig mesophyll (+) H-8105 mesophyll combination resulted in regenerants of mostly normal ngr phenotype. Two regenerants from this combination were proved to be true hybrids by RAPD analysis but they rooted poorely in vitro and did not survive the transfer to soil. The S. ngrgig (+) H-8105 fusion combination was also performed with H-8105 cell suspension derived protoplasts enabling an easy identification of interspecific fusants on basis of their intermediate morphology. From the S. ngrgig mesophyll (+) H-8105 cultured cell combination, many abnormal shoots were regenerated. The two lines which survived had normal ngr phenotype but the presence of tube rosum (tbr) genome in those regenerants was not confirmed by RAPD analysis. No plants with tbr phenotype were obtained from both of S. ngr gig (+) H-8105 combinations. On the contrary, when S. bib mesophyll protoplasts were electrofused with ZEL-1136 mesophyll protoplasts, all regenerated plants had tbr phenotype, indicating much lower morphogenetic potential of S. bulbocastanum in comparison with that of S. nigrum vat. gigantea. However, the hybridity of those regenerants has not been confirmed by RAPD analysis with two different primers. The efficiency of the applied fusion procedure and analysis of the regenerants is discussed.

Tetraploid somatic hybrids of potato (Solanum tuberosum L.) obtained from diploid breeding lines

“…The regeneration efficiency of heterokaryon-derived calli ranged from 6 to 100%. Similar results were obtained by Szczerbakowa et al [29], Rokka et al [30] and Helgeson et al [31]. Putative hybrids were verified with two PCR-based systems using RAPD and semi-random primers.…”

Early characterization of somatic hybrids from symmetric protoplast electrofusion of Solanum pinnatisectum Dun. and Solanum tuberosum L.

“…Borgato et al (2007) found only tetraploids in S. marginatum (2n = 2x = 24). However, wide variability in ploidy level and the morphology of somatic hybrids from any given fusion combination proved more common (Shi et al 2006;Szczerbakowa et al 2003b;Horsman et al 2001;Szczerbakowa et al 2001). The tetraploids produced in this study probably arose from the asymmetric fusion pnt 8166 ?…”

Interspecific somatic hybrids Solanum bulbocastanum (+) S. tuberosum H-8105

“…According to Austin et al (1993), regeneration from protoplasts of the different accession of S. bulbocastanum, PI 275187, was difficult and only three calli out of several thousand tested produced shoots. The regeneration of the S. bulbocastanum (+) H-8105 somatic hybrids, although slow and stunted, was possible presumably due to an input of S. tuberosum genome from the H-8105 parent that was capable of regenerating from the protoplasts as tetraploid (Szczerbakowa et al 2001 ).…”