A 1Ns Disomic Addition from Psathyrostachys Huashanica Keng Confers Resistance to Powdery Mildew in Wheat

Abstract

Powdery mildew is a fungal disease that threatens wheat production throughout the world. Breeding resistant cultivars is an effective way to reduce harm caused by powdery mildew. In this study, 35 wheat-Psathyrostachys huashanica-derived lines were developed by crossing common wheat and P. huashanica Keng (2n = 2x = 14, NsNs) using embryo culture. Resistance to powdery mildew in the derived lines was identified at the seedling and adult stages. Line H5-5-4-2 was selected with immunity to powdery mildew at both growth stages. The chromosome structure of this line was characterized by cytology, genomic in situ hybridization (GISH), and expressed sequence tag-sequence-tagged site (EST-STS) analysis. The chromosome configuration was 2n = 44 = 22II. Two P. huashanica chromosomes with strong hybridization signals were detected by GISH analysis. Among 83 EST-STS markers that covered all seven homologous groups in wheat, three pairs of STS markers, BE497584, BF202643, and BG262410, located in wheat homologous group 1 amplified clear specific bands related to P. huashanica. The results indicated that resistant line H5-5-4-2 was a wheat-P. huashanica 1Ns disomic addition line.

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

“…The most common way to utilize the genome of relative species of wheat is to create wheat-alien–derived lines, including addition lines, substitution lines, translocation lines, and introgression lines, and then cross plus multiple backcross with wheat varieties to obtain new wheat germplasms containing objective traits of alien species ( Li et al, 2008 ). The Ns genome consists of seven homoeologous groups (1–7Ns) that all have been testified useful for wheat breeding improvement because of many beneficial genes: leaf rust resistance genes located in 1Ns, 3Ns, and 7Ns ( Du et al, 2012 , 2014c ; Pang et al, 2014 ); stripe rust resistance genes located in 2Ns, 3Ns, 4Ns, 5Ns, and 7Ns ( Du et al, 2012 , 2014a , 2014b , 2014c ; Li J. C. et al, 2019 ; Li et al, 2020a ); powdery mildew resistance genes located in 1Ns and 5Ns ( Han et al, 2020 ; Li et al, 2020b ); spike characters–related genes located in 4Ns and 6Ns ( Du et al, 2013 , 2014a ); and gluten synthesis–related genes located in 1Ns, 5Ns, and 6Ns ( Zhao et al, 2010 ; Du et al, 2013 ; Li J. C. et al, 2019 ). Years of research and numerous evidences, i.e., chromosomal pairing in meiotic stage, molecular markers studies, southern hybridization, and GISH analysis, all show that Leymus share the same Ns genome from Psathyrostachys , whereas Ns genome in Leymus ought to be a mutational version ( Wang et al, 2006 ; Yen et al, 2009 ).…”

Development and Molecular Cytogenetic Identification of a New Wheat–Psathyrostachys huashanica Keng Translocation Line Resistant to Powdery Mildew

“…The mitotic chromosomes of root tip cells (RTCs) of wheat– P. huashanica translocation line E24-3-1-6-2-1 were prepared and observed as previously described ( Han et al, 2020 ). In brief, seeds of E24-3-1-6-2-1 were germinated in dishes.…”

“…Genomic in situ hybridization was performed to detect P. huashanica chromosomes in E24-3-1-6-2-1 according to a published method ( Walling et al, 2005 ), with minor modifications ( Han et al, 2020 ). The total genomic DNA was extracted from fresh leaves of P. huashanica and Chinese Spring according to the improved cetyl-trimethylammonium bromide (CTAB) method ( Cota-Sánchez et al, 2006 ).…”

“…Afterward, the DNA was labeled with Dig-Nick-Translation Mix/digoxigenin (digoxigenin-11-dUTP, DIG; Roche, Germany) using the nick translation method and then as hybridization probes for GISH. Chromosomes were counterstained with propidium iodide (PI), after which detection and visualization of the P. huashanica chromosomes were conducted according to Han et al (2020) .…”

“…Psathyrostachys huashanica Keng (2 n = 2x = 14, NsNs), a wild relative of common wheat, is a Chinese endemic species that is found only in the Huashan Mountains of China ( Kang et al, 2016 ). It has attracted substantial amounts of attention from wheat breeders due to its desirable traits, such as early maturity, increased numbers of kernels per spike, high tolerance to biotic stress, i.e., cold and drought, and high resistance to multiple diseases ( Chen et al, 1991 ; Kang et al, 2008 , 2016 ; Du et al, 2010 , 2013a , b , c , 2014 ; Han et al, 2015 , 2020 ; Li et al, 2019 , 2020 ). To utilize the desirable traits of P. huashanica , distant crosses have been performed between P. huashanica and wheat since the 1980s ( Chen et al, 1991 ).…”