AUTHOR=Zhang Xiaojun , Li Jianbo , Ge Yudi , Guan Haixia , Li Guangrong , Zhang Shuwei , Wang Xiaolu , Li Xin , Chang Zhijian , Zhang Peng , Jia Juqing , Liu Cheng 

TITLE=Molecular cytogenetic characterization of a new wheat-Thinopyrum intermedium homoeologous group-6 chromosome disomic substitution line with resistance to leaf rust and stripe rust

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1006281

DOI=10.3389/fpls.2022.1006281

ISSN=1664-462X

ABSTRACT=<p><italic>Thinopyrum intermedium</italic> (JJJ<sup>s</sup>J<sup>s</sup>StSt, 2<italic>n</italic> = 6<italic>x</italic> = 42), a member of tertiary gene pool of hexaploid wheat (<italic>Triticum aestivum</italic> L., AABBDD, 2<italic>n</italic> = 6<italic>x</italic> = 42), provides several beneficial genes for wheat improvement. In this study, line CH51 was developed from the BC<sub>1</sub>F<sub>8</sub> progeny of a partial wheat-<italic>Th. intermedium</italic> amphiploid TAI8335 (2<italic>n</italic> = 56) and wheat cultivar (cv.) Jintai 170. Somatic metaphase chromosome counting showed that CH51 had stable 42 chromosomes. Genomic <italic>in situ</italic> hybridization (GISH) analysis showed that CH51 had 40 wheat chromosomes and two <italic>Th. intermedium</italic> chromosomes involving translocation between J<sup>s</sup>- and St-genome chromosomes. Non-denaturing fluorescence <italic>in situ</italic> hybridization (ND-FISH) analysis revealed that CH51 lacked a pair of wheat chromosome 6B. Wheat 55K SNP array analysis verified that chromosome 6B had the highest percentage of missing SNP loci in both CH51 and Chinese Spring (CS) nullisomic 6B-tetrasomic 6D (CS-N6BT6D) and had the highest percentage of polymorphic SNP loci between CH51 and cv. Jintai 170. We identified that CH51 was a wheat-<italic>Th. intermedium</italic> T6StS.6J<sup>s</sup>L (6B) disomic substitution line. Disease resistance assessment showed that CH51 exhibited high levels of resistance to the prevalent Chinese leaf rust and stripe rust races in the field. Therefore, the newly developed line CH51 can be utilized as a potential germplasm in wheat disease resistance breeding.</p>