Molecular Cytogenetic and Morphological Identification of a Wheat–L. mollis 1Ns(1D) Substitution Line, DM45

Abstract

Leymus mollis (Trin.) Pilger (NsNsXmXm, 2n = 28), a wild relative of common wheat, possesses many potentially valuable traits for wheat breeding, i.e., strong and short stems, long spikes with numerous spikelets, tolerance to drought and cold, and resistance to many fungal and bacterial diseases. In this study, we hybridized a wheat-L. mollis triple substitution line 05DM6 × Triticum aestivum L. cv. 7182 to obtain DM45, a single chromosome substitution line. Cytological studies demonstrated that DM45 had a chromosome karyotype of 2n = 42 = 21II. Genomic in situ hybridization analysis indicated that DM45 had a pair of Ns chromosomes from L. mollis. Analysis with DNA markers, i.e., two simple sequence repeats (Xgdm111 and Xgdm126) and two expressed sequence tag-sequence tagged sites (CD453004 and BE443796), showed that the wheat 1Ds chromosome were substituted with a pair of 1Ns chromosomes from L. mollis in DM45. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis suggested that DM45 possessed Ns genomespecific bands in the low and high molecular weight glutenin subunit regions, whereas it lacked one glutenin subunit translated from genes on chromosome 1D, thereby confirming that DM45 was a wheat-L. mollis 1Ns#1 (1D) disomic substitution line. Agronomic trait evaluations showed that DM45 was much improved in terms of the 1000-grain weight and the protein and glutenin contents of its seeds, as well as having more florets and spikelets compared with its relative, common wheat variety 7182. The substitution line DM45 could be used as a novel germplasm in wheat genetic and breeding programs.

Cytogenetic and Molecular Marker Analyses of a Novel Wheat–Psathyrostachys huashanica 7Ns Disomic Addition Line with Powdery Mildew Resistance

“…shares the same Ns genome from Psathyrostachys Nevski [ 44 , 45 , 46 ]. Some wheat– Leymus mollis derived lines encompassing alien Ns chromosomes have also been produced, such as two 3Ns (3D) disomic substitution lines with resistance to either leaf rust or powdery mildew [ 26 , 47 ], a 1Ns (1D) disomic substitution line with improved protein and glutenin contents [ 48 ], a 2Ns, 3Ns (2D, 3D) double substitution line with resistance to yellow rust and Fusarium head blight [ 49 ], and two 2Ns (2D) and 7Ns (7D) disomic substitution lines resistant to stripe rust [ 50 , 51 ]. Nonetheless, no relevant reports describing the transfer of powdery mildew resistance genes from chromosome 7Ns of Leymus or Psathyrostachys to common wheat have appeared.…”

DEFECTIVE ENDOSPERM-D1 (Dee-D1) is crucial for endosperm development in hexaploid wheat

“…Substitution of 1Ns chromosome in Leymus mollis Trin. (a wild relative of common wheat) by chromosome 1D (1Ns(1D)) improve wheat yield by increasing florets and spikelets number, grain weight, spike length and thousand-grain weight 26 . EARLY FLOWERING 3 (ELF3 ), a candidate for the earliness per se locus Eps-Am 1 in wheat 27 , 28 , plays a crucial role in flowering time, which in turn influences development and grain yield.…”

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

“…Octoploid Tritileymus (2 n = 8x = 56, AABBDDNsNs or AABBDDXmXm) displayed excellent agronomic characteristics, such as large grain and panicle, many flowers, and resistance to various fungal diseases ( Wang et al., 2000 ; Wang et al., 2012 ). A series of addition, substitution, and translocation lines were obtained by crossing durum wheat or common wheat with octoploid Tritileymus (2 n = 56, AABBDDNsNs) ( Bao et al., 2012 ; Zhao et al., 2013 ; Pang et al., 2014a ; Pang et al., 2014b ; Zhao et al., 2016 ; Zhao et al., 2019 ). Several wheat- L. mollis addition lines and substitution lines with resistance to stripe rust and powdery mildew using a cross between common wheat 7182 and partial amphiploid M47 (2 n = 8x = 56, AABBDDNsNs) were created previously ( Yang et al., 2014a ; Yang et al., 2015 ; Yang et al., 2017 ; Zhang et al., 2017a ; Yang et al., 2020 ).…”