The use of cytogenetic tools for studies in the crop-to-wild gene transfer scenario

Abstract

Interspecific hybridization in plants is an important evolutionary phenomenon involved in the dynamics of speciation that receives increasing interest in the context of possible gene escapes from transgenic crop varieties. Crops are able to cross-pollinate with a number of wild related species and exchange chromosome segments through homoeologous recombination. In this paper, we review a set of cytogenetic techniques that are appropriate to document the different steps required for the stable introgression of a chromosome segment from a donor species (i.e., the crop) into a recipient species (i.e., the wild). Several examples in hybrids and derivatives are given to illustrate how these approaches may be used to evaluate the potential for gene transfer between crops and wild relatives. Different techniques, from classical chromosome staining methods to recent developments in molecular cytogenetics, can be used to differentiate genomes and identify the chromosome regions eventually involved in genetic exchanges. Some clues are also given for the study of fertility restoration in the interspecific hybrid forms.

Diverse chromosome complements in the functional gametes of interspecific hybrids of MT- and A-karyotype Lycoris spp.

“…Green signals indicate the positions of 45S rDNA loci on 3 T-type and one A-type chromosomes. Bar 10 lm pattern of homoeologous recombination and the amount of introgression have been studied in diverse groups of plants (for review see Benavente et al 2008). Among those achievements, the production of Festuloliums (Festuca 9 Lolium hybrids) are the most well-known and successful (Kopecky et al 2008).…”

“…With well-developed genomic in situ hybridization (GISH) technique, one can cytologically discriminate closely related genomes and precisely dissect the chromosome pairing behaviors at meiosis of interspecific hybrids (Benavente et al 2008). For better discrimination, the totalgenome DNA of another closely related species without labeling is usually used as competitor (blocking agent) to probe DNA in GISH (Anamthawat-Jonsson et al 1990).…”

FISH Karyotype Analysis of Four Wild Cucurbitaceae Species Using 5S and 45S rDNA Probes and the Emergence of New Polyploids in Trichosanthes kirilowii Maxim.

“…Efficient breeding programs that produce crops with established desirable traits will maximize the exploitation of these agriculturally and economically significant traits. Cytogenetic information plays an important role in breeding programs for some of the world's most important crops, such as wheat, maize (Albert et al, 2010;Benavente et al, 2008;Icso et al, 2014) and watermelon (Sain et al, 2002). Considering the potential of the four wild cucurbits (i.e., Citrullus lanatus (Thunb.)…”

Detection of various U and M chromosomes in wheat-Aegilops biuncialis hybrids and derivatives using fluorescence in situ hybridisation and molecular markers

“…Pre-breeding is a promising alternative for the inclusion of Aegilops genetic resources in wheat breeding programmes. Alien chromosome additions are useful tools in plant genetics research and breeding, as they serve as a bridge for the transfer of agronomically useful traits from wild species into cultivated wheat (Jiang et al 1994b;Chang & De Jong 2005;Benavente et al 2008). The 2U b wheat-Ae.…”