Short‐term hybridisation activates Tnt1 and Tto1 Copia retrotransposons in wild tuber‐bearing Solanum species

Abstract

Interspecific hybridisation in tuber-bearing species of Solanum is a common phenomenon and represents an important source of variability, crucial for adaptation and speciation of potato species. In this regard, the effects of interspecific hybridisation on retrotransposon families present in the genomes, and their consequent effects on generation of genetic variability in wild tuber-bearing Solanum species, are poorly characterised. The aim of this study was to analyse the activity of retrotransposons in inter- and intraspecific hybrids between S. kurtzianum and S. microdontum, obtained by controlled crosses, and the effects on morphological, genetic and epigenetic variability. For genetic and epigenetic analysis, S-SAP (sequence-specific amplification polymorphism) and TMD (transposon methylation display) techniques were used, respectively, with specific primers for Tnt1 and Tto1 retrotransposon families (Order LTR, Superfamily Copia). The results indicate that at morphological level, interspecific hybrid genotypes differ from their parental species, whereas derived intraspecific hybrids do not. In both cases, we observed significant reductions in pollen grain viability, and a negative correlation with Tnt1 mobility. Both retrotransposons, Tto1 and Tnt1, were mobilised in the genotypes analysed, with mobility ranging from 0 to 7.8%. Furthermore, at the epigenetic level, demethylation was detected in the vicinity of Tnt1 and Tto1 in the hybrids compared with the parental genotypes. These patterns were positively correlated with the activity of the retrotransposons. The results suggest a possible mechanism through which hybridisation events generate genetic variability in tuber-bearing species of Solanum through retrotranposon activation.

The landscape of transposable elements and satellite DNAs in the genome of a dioecious plant spinach (Spinacia oleracea L.)

“…For example, five families of LTR-REs represent approximately 80% of the maize RE repertoire [1, 26], and a single Ty3- Gypsy -like RE accounts for approximately 38% of the genome of Vicia pannonica [27]. The mechanisms behind the proliferation of several RE families or lineages are poorly understood, and the most accepted explanation is that these families or lineages lost their silencing cellular mechanisms of the host genome [28, 29].…”

Plant diversity and transcriptional variability assessed by retrotransposon-based molecular markers

“…In comparison to their parental genotype, hybrids were epigenetically changed by demethylation in the vicinity of Tnt1 and Tto1, which correlates with the activity of retrotransposons. Those results indicate that retrotransposon activation can lead to genetic variability in tuberbearing spe cies of Solanum via hybridization (Paz et al, 2015).…”

“…IRAP and REMAP methods have been used in gene map ping in cereals (Manninen et al, 2000;Boyko et al, 2002;Tanhuanpaa et al, 2007), in studies of genome evolution in the Solanaceous crop species (Tek et al, 2005;Tam et al, 2009), in a variety of applications, including measurement of genetic diversity and population structure, chromatin modification and epigenetic reprogramming, similarity and cladistic relation ships, determination of essential derivation, markerassisted selection, detection of somaclonal variation (Ishizaki, Kato, 2005;Lightbourn et al, 2007;Tam et al, 2009;Belyayev et al, 2010;Smykal et al, 2011;Wenke et al, 2011;Hosid et al, 2012;Yin et al, 2013;Moisy et al, 2014;Sharma, Nandineni, 2014;Tang et al, 2014;Paz et al, 2015).…”

Tnt1 retrotransposon as an efficient tool for development of an insertional mutant collection of Lotus japonicus

“…Activity of Tnt1 and Tto1 retrotransposons has been detected in interspecific hybrids of tuber-bearing species of Solanum, and represents a source of genetic variability, important for adaptation of potato species (Paz et al 2015).…”