Molecular Cytogenetics of Chromosome 2St as Well as Chromosome 3St Derived from Thinopyrum Intermedium and Thinopyrum Ponticum

Abstract

Owing to the excellent resistance to abiotic and biotic stress, Thionpyrum intermedium (2n = 6x = 42, JJJsJsStSt) and Thinopyrum ponticum (2n = 10x = 70) are both widely utilized in wheat germplasm innovation programs. Disomic substitution lines (DSLs) carrying one pair of alien chromosomes are valuable bridge materials for novel genes transmission. In this study, six wheat-Thinopyrum DSLs were derived from crosses between Abbondanza nullisomic lines (2n = 40) and two octoploid Trititrigia lines (2n = 8x = 56), characterized by a sequential fluorescence in situ hybridization (FISH)-genome in situ hybridization (GISH), a multicolor GISH (mc-GISH), and an analysis of wheat 15K SNP array combined with molecular marker selection. ES-9 and ES-10 were two wheat- Th. ponticum disomic substitution lines, DS2St (2A) and DS3St (3D). While ES-23, ES-24, ES-25, and ES-26 were four wheat- Th. intermedium disomic substitution lines, DS2St (2A), DS3St (3D), DS2St (2B), DS2St (2D). The FISH karyotypes of Th. ponticum 2St/3St chromosomes were well coincident with the ones of Th. intermedium. The chromosome configurations of F1 hybrids derived from crosses between ES-23 and ES-9, as well as ES-24 and ES-10 were mostly formed 21Ⅱ. Four St-chromosome-specific markers were developed by specific-locus amplified fragment sequencing (SLAF-seq). Additionally, the substitution lines containing chromosome 2St conferred higher thousand-kernel weight and stripe rust resistance at adult stages, while the substitution lines containing chromosome 3St were highly resistant to stripe rust at all stages. Therefore, these six substitution lines could serve as useful bridging parents for wheat genetic improvement.

Identification and DNA Marker Development for a Wheat-Leymus mollis 2Ns (2D) Disomic Chromosome Substitution

“…It also provides a strategy for developing markers to detect and track alien chromosomes or genes from wheat wild relatives in the wheat background. Based on the SLAF-seq technology, 507 STS markers of Thinoprum ponticum 1Js chromosomes, 89 specific markers of Thinopyrum elongatum 7E chromosomes, two 2St-chromosome-specific markers, and two 3St-chromosome-specific markers were developed respectively [ 11 , 12 , 13 ]. Therefore, SLAF-seq is a feasible method to develop sufficient markers for accurate detection of alien chromatin, which could promote the further exploitation of beneficial genes for wheat genetic improvement.…”