Production and Identification of Wheat-Agropyron cristatum 2P Translocation Lines

Abstract

Agropyron cristatum (L.) Gaertn. (2n = 28, PPPP), a wild relative of common wheat, possesses many potentially valuable traits that can be transferred to common wheat through breeding programs. The wheat-A. cristatum disomic addition and translocation lines can be used as bridge materials to introduce alien chromosomal segments to wheat. Wheat-A. cristatum 2P disomic addition line II-9-3 was highly resistant to powdery mildew and leaf rust, which was reported in our previous study. However, some translocation lines induced from II-9-3 have not been reported. In this study, some translocation lines were induced from II-9-3 by 60Co-γ irradiation and gametocidal chromosome 2C and then identified by cytological methods. Forty-nine wheat-A. cristatum translocation lines were obtained and various translcoation types were identified by GISH (genomic in situ hybridization), such as whole-arm, segmental and intercalary translocations. Dual-color FISH (fluorescent in situ hybridization) was applied to identify the wheat chromosomes involved in the translocations, and the results showed that A. cristatum 2P chromosome segments were translocated to the different wheat chromosomes, including 1A, 2A, 3A, 4A, 5A, 6A, 7A, 3B, 5B, 7B, 1D, 4D and 6D. Many different types of wheat-A. cristatum alien translocation lines would be valuable for not only identifying and cloning A. cristatum 2P-related genes and understanding the genetics and breeding effects of the translocation between A. cristatum chromosome 2P and wheat chromosomes, but also providing new germplasm resources for the wheat genetic improvement.

RNA-Seq Analysis Provides the First Insights into the Phylogenetic Relationship and Interspecific Variation between Agropyron cristatum and Wheat

“…This conclusion is also supported by the phylogenetic analysis between P and the wheat A, B, and D genomes (Figure 4 ). These results were the first to reveal the evolutionary relatedness between A. cristatum and the wheat A, B, and D genomes and explained that the wheat A genome and B genome had a higher number of chromosome arrangements with A. cristatum chromosomes than the D genome (Badaeva et al, 2007 ; Li et al, 2016 ). Interestingly, the variant density in the transcriptional regions was relatively lower in the telomeric and centromeric regions than that in the other chromosomal regions (Figure 6G ).…”

“…Although the wheat- A. cristatum derivatives represent an attractive source of value-added traits (Zhang et al, 2015b ; Li et al, 2016 ), the genetic relationship and variants, which represent the fundamental key to breeding success and provide a basis for breeders to select varieties with a constantly improving yield performance (Bedő and Láng, 2015 ), of A. cristatum compared to wheat at the molecular level remain unknown. This study showed that A. cristatum had abundant genetic resources and diversity compared to wheat from the various aspects described below.…”

“…In the early 1990s, the inter-generic hybridization of wheat cv. Fukuhokomugi (Fukuho) and A. cristatum accession Z559 was successfully completed via a wide cross and embryo rescue (Li, 1995 ), and then, many additional lines with excellent characteristics, including disomic substitution lines, translocation lines, and introgression lines, were produced (Zhang et al, 2015b ; Li et al, 2016 ). Several of these lines have been used in wheat-breeding programmes, such as Pubing3504 and Pubing3228, which exhibit an increased number of spikelets and florets (Chen et al, 2012 ).…”

Construction of Agropyron Gaertn. genetic linkage maps using a wheat 660K SNP array reveals a homoeologous relationship with the wheat genome

“…Subsequently, a set of additional wheat– A. cristatum lines and disomic substitution lines were produced and characterized (Han et al ., ; Wu et al ., ), some of which will be valuable for future wheat breeding as novel germplasms (Chen et al ., ; Wu et al ., ). For example, the 6P disomic addition line 4844 shows high yield characteristics for the number of florets and kernels per spike compared with those of its wheat parent (Li et al ., ; Wu et al ., ), and resistance to powdery mildew and leaf rust was transferred from A. cristatum to common wheat (Li et al ., ).…”

A resource of large-scale molecular markers for monitoring Agropyron cristatum chromatin introgression in wheat background based on transcriptome sequences

“…Among these EST-STS markers, 6063 can be used in the identification of wide crosses in the single-receipt Fukuho parent background, and 3070 A. cristatum- specific markers in eight wheat variety backgrounds can be applied to molecular marker-assisted selection of A. cristatum introgressions into commercial varieties. In the present study, these markers have been applied successfully for the physical mapping of 2P, 6P and 7P alien chromatin fragments in A. cristatum –wheat introgression lines 27 , 30 , 34 , 35 .…”