Production of alien chromosome additions and their utility in plant genetics

Abstract

Breeding programs aiming at transferring desirable genes from one species to another through interspecific hybridization and backcrossings often produce monosomic and disomic additions as intermediate crossing products. Such aneuploids contain alien chromosomes added to the complements of the recipient parent and can be used for further introgression programs, but lack of homoeologous recombination and inevitable segregation of the alien chromosome at meiosis make them often less ideal for producing stable introgression lines. Monosomic and disomic additions can have specific morphological characteristics, but more often they need additional confirmation of molecular marker analyses and assessment by fluorescence in situ hybridization with genomic and chromosome-specific DNA as probes. Their specific genetic and cytogenetic properties make them powerful tools for fundamental research elucidating regulation of homoeologous recombination, distribution of chromosome-specific markers and repetitive DNA sequences, and regulation of heterologous gene expression. In this overview we present the major characteristics of such interspecific aneuploids highlighting their advantages and drawbacks for breeding and fundamental research.

Molecular and biochemical identification of alien chromosome additions in shallot (Allium cepa L. Aggregatum group) carrying extra chromosome(s) of bunching onion (A. fistulosum L.)

“…These indicate that the enzyme genes which catalyze sucrose biosynthesis are also important for fructan productions. The interpretation of biochemical and morphological phenotypes of alien monosomic addition lines and singlealien deletion lines is challenging since genes on the alien chromosome are expressed in the diploid genetic background of a divergent parent (Chang and de Jong, 2005). Support for the idea that heterozygosity or polyploidy in sucrose metabolism genes such as SPS and sucrose synthase (SuSy) can induce marked changes in sugar metabolism is provided by studies in maize.…”

Wheat–barley hybridization: the last 40 years

“…Alien additions are primarily produced to add specific desirable genes to a crop species (Gale and Miller 1987), but addition lines can be used for many other purposes, such as mapping genes and markers on introgressed alien chromosomes, examining alien gene regulation, understanding meiotic pairing behaviour and chromosome structure, and isolating individual chromosomes and genes of interest (Chang and de Jong 2005;Cho et al 2006). The wheat-barley addition lines produced in various cultivar combinations (CS 9 Betzes, Mv9 kr1 9 Igri, Asakaze 9 Manas) had several morphological traits in common (Molnár-Láng et al 2012).…”

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

“…The production of addition series is also restricted by the different transmission rates of the individual Aegilops chromosomes, as in this study the transferability of the 3M b , 2U b and 6U b chromosomes of Ae. biuncialis chromosomes varied greatly (99, 91 and 0%), which is possibly due to deviations in the centromere structure of the alien chromosomes (Chang et al 2005). The selection of disomic plants from the selfing progenies of monosomic plants is very labourintensive, due to the rapid elimination of single added chromosomes in wheat (Jiang et al 1994b).…”

“…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.…”