Genetic Rearrangements of Six Wheat–Agropyron cristatum 6P Addition Lines Revealed by Molecular Markers

Abstract

Agropyron cristatum (L.) Gaertn. (2n = 4x = 28, PPPP) not only is cultivated as pasture fodder but also could provide many desirable genes for wheat improvement. It is critical to obtain common wheat–A. cristatum alien disomic addition lines to locate the desired genes on the P genome chromosomes. Comparative analysis of the homoeologous relationships between the P genome chromosome and wheat genome chromosomes is a key step in transferring different desirable genes into common wheat and producing the desired alien translocation line while compensating for the loss of wheat chromatin. In this study, six common wheat–A. cristatum disomic addition lines were produced and analyzed by phenotypic examination, genomic in situ hybridization (GISH), SSR markers from the ABD genomes and STS markers from the P genome. Comparative maps, six in total, were generated and demonstrated that all six addition lines belonged to homoeologous group 6. However, chromosome 6P had undergone obvious rearrangements in different addition lines compared with the wheat chromosome, indicating that to obtain a genetic compensating alien translocation line, one should recombine alien chromosomal regions with homoeologous wheat chromosomes. Indeed, these addition lines were classified into four types based on the comparative mapping: 6PI, 6PII, 6PIII, and 6PIV. The different types of chromosome 6P possessed different desirable genes. For example, the 6PI type, containing three addition lines, carried genes conferring high numbers of kernels per spike and resistance to powdery mildew, important traits for wheat improvement. These results may prove valuable for promoting the development of conventional chromosome engineering techniques toward molecular chromosome engineering.

Chromosomal Localization of Genes Conferring Desirable Agronomic Traits from Wheat-Agropyron cristatum Disomic Addition Line 5113

“…All the seven SLAF-tags from 4844–12 were located on the linkage group (LG) 6 of Agropyron Gaertn., indicating that 4844–12 was a 6P disomic addition line. The result was consistent with before [31]. 15 out of 20 SLAF-tags (accounting for 75%) from 5113 were localized on LG6, and others were localized on other different LGs (Fig 2A), such as one tag on LG1, one tag on LG2, two tags on LG3, and one tag on LG7.…”

“…cristatum accession Z559 and Fukuho, followed by self-pollination for six generations [31]. F 1 , BC 1 F 1 and BC 1 F 2 populations were then constructed from the crosses between 5113 and Fukuho, using Fukuho as the recurrent parent.…”

“…Fukuhokomugi (Fukuho, 2n = 6x = 42; AABBDD) and A . cristatum [29,30], including addition, translocation and introgression lines [31–35]. 5113 was one of the wheat- A .…”

New molecular markers and cytogenetic probes enable chromosome identification of wheat-Thinopyrum intermedium introgression lines for improving protein and gluten contents

“…Compared with previous single-end RAD sequencing, pair-end reads obtained by SLAF-seq can somewhat increase marker specificity and accuracy, which has been used for mapping the Th. elongatum 7E chromosome (Chen et al 2013) and Agropyron cristatum (P genome) chromosomes (Han et al 2014). In this study, we were able to develop 37 Th.…”

A high-density genetic map for P genome of Agropyron Gaertn. based on specific-locus amplified fragment sequencing (SLAF-seq)

“…The detection of alien chromosome/fragment/gene in the wheat background can provide a guide to utilize the wheat-A. cristatum derivative lines with high efficiency, and a great deal of efforts have been made using genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH), molecular markers from A. cristatum Wu et al 2010;Song et al 2013;Han et al 2014). These work provide valuable clues for the application of wheat-A.…”