AUTHOR=Li Jiachuang , Li Jiaojiao , Cheng Xueni , Zhao Li , Yang Zujun , Wu Jun , Yang Qunhui , Chen Xinhong , Zhao Jixin 

TITLE=Molecular Cytogenetic and Agronomic Characterization of the Similarities and Differences Between Wheat–Leymus mollis Trin. and Wheat–Psathyrostachys huashanica Keng 3Ns (3D) Substitution Lines

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.644896

DOI=10.3389/fpls.2021.644896

ISSN=1664-462X

ABSTRACT=<p><italic>Psathyrostachys huashanica</italic> Keng (2<italic>n</italic> = 2<italic>x</italic> = 14, NsNs) and <italic>Leymus mollis</italic> Trin. (2<italic>n</italic> = 4<italic>x</italic> = 28, NsNsXmXm) are valuable resources for wheat breeding improvement as they share the Ns genome, which contains diverse resistance genes. To explore the behaviors and traits of Ns chromosomes from the two species in wheat background, a series of wheat–<italic>P. huashanica</italic> and wheat–<italic>L. mollis</italic> substitution lines were developed. In the present study, line DH109 (F<sub>7</sub> progeny of wheat–<italic>P. huashanica</italic> heptaploid line H8911 × durum wheat Trs-372) and line DM131 (F<sub>8</sub> progeny of wheat–<italic>L. mollis</italic> octoploid line M842 × durum wheat Trs-372) were selected. Cytological observation combined with genomic <italic>in situ</italic> hybridization experiments showed that DH109 and DM131 each had 20 pairs of wheat chromosomes plus a pair of alien chromosomes (Ns chromosome), and the pair of alien chromosomes showed stable inheritance. Multiple molecular markers and wheat 55K SNP array demonstrated that a pair of wheat 3D chromosome in DH109 and in DM131 was substituted by a pair of <italic>P. huashanica</italic> 3Ns chromosome and a pair of <italic>L. mollis</italic> 3Ns chromosome, respectively. Fluorescence <italic>in situ</italic> hybridization (FISH) analysis confirmed that wheat 3D chromosomes were absent from DH109 and DM131, and chromosomal FISH karyotypes of wheat 3D, <italic>P. huashanica</italic> 3Ns, and <italic>L. mollis</italic> 3Ns were different. Moreover, the two lines had many differences in agronomic traits. Comparing with their wheat parents, DH109 expressed superior resistance to powdery mildew and fusarium head blight, whereas DM131 had powdery mildew resistance, longer spike, and more tiller number. Therefore, Ns genome from <italic>P. huashanica</italic> and <italic>L. mollis</italic> might have some different effects. The two novel wheat–alien substitution lines provide new ideas and resources for disease resistance and high-yield breeding on further utilization of 3Ns chromosomes of <italic>P. huashanica</italic> or <italic>L. mollis</italic>.</p>