Genetic and Epigenetic Variations Induced by Wheat-Rye 2R and 5R Monosomic Addition Lines

Abstract

BackgroundMonosomic alien addition lines (MAALs) can easily induce structural variation of chromosomes and have been used in crop breeding; however, it is unclear whether MAALs will induce drastic genetic and epigenetic alterations.Methodology/Principal FindingsIn the present study, wheat-rye 2R and 5R MAALs together with their selfed progeny and parental common wheat were investigated through amplified fragment length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP) analyses. The MAALs in different generations displayed different genetic variations. Some progeny that only contained 42 wheat chromosomes showed great genetic/epigenetic alterations. Cryptic rye chromatin has introgressed into the wheat genome. However, one of the progeny that contained cryptic rye chromatin did not display outstanding genetic/epigenetic variation. 78 and 49 sequences were cloned from changed AFLP and MSAP bands, respectively. Blastn search indicated that almost half of them showed no significant similarity to known sequences. Retrotransposons were mainly involved in genetic and epigenetic variations. Genetic variations basically affected Gypsy-like retrotransposons, whereas epigenetic alterations affected Copia-like and Gypsy-like retrotransposons equally. Genetic and epigenetic variations seldom affected low-copy coding DNA sequences.Conclusions/SignificanceThe results in the present study provided direct evidence to illustrate that monosomic wheat-rye addition lines could induce different and drastic genetic/epigenetic variations and these variations might not be caused by introgression of rye chromatins into wheat. Therefore, MAALs may be directly used as an effective means to broaden the genetic diversity of common wheat.

Harnessing Genetic Diversity of Wild Gene Pools to Enhance Wheat Crop Production and Sustainability: Challenges and Opportunities

“…In fact, since Barbara McClintock's intuition that "species crosses are another potent source of genome modification that could yield TE activation" [72], a large body of evidence has demonstrated that the merging of parental species in hybrids and allopolyploids can lead to a "genomic shock", which triggers the dysregulation of normal cell functions and various forms of pertubations, almost invariably resulting in activation of previously silent transposable elements (TEs) [73][74][75]. Besides that in complete interspecific hybrids, epigenetic changes, particularly the alteration of DNA methylation patterns, have been observed in introgression lines of rice [76,77] and wheat [78,79] involving even sub-chromosomal amounts of alien chromatin. In some such contexts, sequences that were corresponding to TEs were shown to be the main target of altered DNA methylation [79].…”

“…Besides that in complete interspecific hybrids, epigenetic changes, particularly the alteration of DNA methylation patterns, have been observed in introgression lines of rice [76,77] and wheat [78,79] involving even sub-chromosomal amounts of alien chromatin. In some such contexts, sequences that were corresponding to TEs were shown to be the main target of altered DNA methylation [79].…”

Genetic and epigenetic alterations induced by different levels of rye genome integration in wheat recipient

“…Another study investigated the genetic stability of wheat-rye ("Chinese Spring" x "Imperial") disomic addition lines, by using the Feulgen method and fluorescent in situ hybridization (Szakács and Molnár-Láng, 2010). Subsequent research on wheat-rye 2R and 5R indicated that wheat-rye monosomic addition lines could induce different and drastic genetic/epigenetic variations, and these variations might not be caused by introgression of rye chromatins into wheat (Fu et al, 2013).…”

“…Chromosome instability and genome rearrangements in wheat-rye addition lines have also been observed (Bento et al, 2010;Szakács and Molnár-Láng, 2010). Drastic genetic and epigenetic variations were induced by wheat-rye 2R and 5R monosomic addition lines (Fu et al, 2013).…”

Efficient Induction of Wheat-Agropyron cristatum 6P Translocation Lines and GISH Detection

“…In recent years, modern cultivation systems have given rise to the sharp loses of wheat genetic diversity. Genetic erosion makes wheat increasingly vulnerable to biotic and abiotic stresses [2–5]. On the other hand, the increase of world population and the decrease in acreage of farmland require a much higher wheat yield to meet the need of humankind.…”