Cytogenetic identification and molecular marker development of a novel wheat-Leymus mollis 4Ns(4D) alien disomic substitution line with resistance to stripe rust and Fusarium head blight

Abstract

Leymus mollis (Trin.) Pilg. (2n = 4x = 28, NsNsXmXm) potentially harbours useful genes that might contribute to the improvement of wheat. We describe M862 as a novel wheat-L. mollis alien disomic substitution line from a cross between wheat cv. 7182 and octoploid Tritileymus M47. Cytological observations indicate that M862 has a chromosome constitution of 2n = 42 = 21II. Two 4D chromosomes of wheat substituted by two L. mollis Ns chromosomes were observed, using the GISH and ND-FISH analyses. Molecular marker, 55K SNP array and wheat-P. huashanica liquid array (GenoBaits®WheatplusPh) analyses further indicate that the alien chromosomes are L. mollis 4Ns. Therefore, it was deduced that M862 was a wheat-L. mollis 4Ns(4D) alien disomic substitution line. There were also changes in chromosomes 1A, 1D, 2B and 5A detected by ND-FISH analysis. Transcriptome sequencing showed that the structural variation of 1D, 1A and 5A may have smaller impact on gene expression than that for 2B. In addition, a total of 16 markers derived from Lm#4Ns were developed from transcriptome sequences, and these proved to be highly effective for tracking the introduced chromosome. M862 showed reduced height, larger grains (weight and width), and was highly resistance to CYR32 and CYR34 stripe rust races at the seedling stage and mixed stripe rust races (CYR32, CYR33 and CYR34) at the adult stage. It was also resistance to Fusarium head blight (FHB). This alien disomic substitution line M862 may be exploited as an important genetic material in the domestication of stipe rust and FHB resistance wheat varieties.

The addition of Psathyrostachys Huashanica Keng 6Ns large segment chromosomes has positive impact on stripe rust resistance and plant spikelet number of common wheat

“…5c1). The standard FISH idiogram of common wheat was referenced to Tang et al [ 34 ] and Du et al [ 44 ]. The pattern of probes showed that the 6D chromosomes in D88-2a had normal FISH signals as it in the parent 7182, and the additional P. huashanica 6Ns chromosomes had no hybridization signals as it in P. huashanica by using the probe set of pSc119.2 and pTa535-1 (Fig.…”

“…Previously, a wheat SNP array was used to analyse wheat-alien substitution and translocation lines because the lost wheat chromosomes caused a large number of deletions in SNP loci [ 44 ]. This study found that the 15 K SNP array could also accurately identify the homoeologous groups of alien chromosomes in addition lines, which might be because the genotype of SNPs on the target homologous group chromosomes were affected by alien chromosomes.…”

Molecular Cytological Analysis and Specific Marker Development in Wheat-Psathyrostachys huashanica Keng 3Ns Additional Line with Elongated Glume

“…Developing accurate markers using transcriptome sequencing technology is more effective. Compared with traditional methods, modern sequencing technology could provide a precise and rich source for developing specific markers [ 52 ]. For example, specific markers on the Dasypyrum villosum chromosome were designed via genotyping-by-sequencing (GBS) [ 53 ].…”