Solanum Pennellii La716 as a Source of Genes Improving in Vitro Organogenesis in Cultivated Tomato

The Quest for a Key Gene Controlling Acquisition of Cell Competence During In Vitro Organogenesis in Tomato

“…Solanum pennellii cv. LA716 is another desert dwelling wild species of tomato from Peru that was documented to show high in vitro regeneration capacity (Arikita et al, 2012). A study using 46 introgression lines (ILs) of S. pennellii into S. lycopersicum cv.…”

“…Indeed, tomato natural wild species in general display higher organogenic capacity in comparison to their domesticated counterparts (Peres et al, 2001). This trait is considered as an adaptation to harsh ecological niches occupied by the wild species in order to fend off and recover from various biotic and abiotic stresses (Arikita et al, 2012). Associated ex vitro phenotypes, such as prolific branching, and extensive investment of resources in above-and below-ground biomass used for foraging resources are associated with highly organogenic wild species and are often absent in domesticated species (Pino et al, 2010;Lombardi-Crestana et al, 2012) All these ex vitro phenotypes rely heavily on the availability and the activity of a meristematic tissue competent for organogenic induction.…”

“…On the other hand, in tomato, direct incubation on either RIM or SIM without an intervening CIM incubation stage produces sufficient shoot or root organogenesis in regenerant genotypes (de Siqueira Pinto et al, 2017). However, not all explant types and genotypes are easily amenable to these established regeneration protocols (Arikita et al, 2012;Pino et al, 2010). We know that certain plant genotypes show reduced or complete recalcitrance to organogenesis.…”

“…We were able to confine the original Rg1 locus discovered over two decades ago (Koornneef et al, 1993), containing 293 putative candidates down to 29 candidate genes in two separate sub loci. We capitalized on the preserved genomic synteny across tomato species such as S. pennellii, S. peruvianum and S. lycopersicum within the putative Rg1 genomic region to compare across experiments (Arikita et al, 2012;Chitwood et al, 2013;Siqueira Pinto et al, 2017). Here, moving one step further, by using gene expression characterization and DNA sequence analysis of their coding regions, we were able to eliminate 7 more genes from the 28 candidates: Solyc03g007960, Solyc03g007970, Solyc03g007980, Solyc03g025170, Solyc03g025220, Solyc03g025290…”

“…peruvianum (Koornneef et al, 1993), S. pennellii (Arikita et al, 2012), S. pimpinellifolium (De Faria et al, 2002) and S. chilense (Satoh et al, 2000) are also highly regenerant, while most cultivated varieties of S. lycopersicum are largely recalcitrant. This suggests that high regeneration and associated traits are shared by tomato wild genotypes although they may display allelic variation in the same locus.…”